Patent Publication Number: US-2021175780-A1

Title: Rotating electric machine and vehicle wheel using rotating electric machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of International Application No. PCT/JP2019/028952, filed Jul. 24, 2019, which claims priority to Japanese Patent Application No. 2018-139846, filed Jul. 25, 2018, and Japanese Patent Application No. 2019-131489, filed Jul. 16, 2019. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a rotating electric machine and a vehicle wheel using the rotating electric machine. 
     Background Art 
     An in-wheel motor using an outer-rotor-type rotating electric machine including a stator and a rotor is known. In the in-wheel motor, the outer-rotor-type motor is housed inside a wheel. The stator is fixed to an inner frame on an inner side thereof, and the rotor is supported so as to be capable of rotating integrally with the wheel. The inner frame is provided in an annular shape so as to surround a shaft and is configured such that a bearing is interposed between the inner frame and the shaft. 
     SUMMARY 
     One aspect of the present disclosure provides a rotating electric machine that includes: a field element that includes a magnet portion that includes a plurality of magnetic poles of which polarities alternate in a circumferential direction; an armature that includes an armature winding of multiple phases; a power converter that is electrically connected to the armature winding: a plurality of electrical components that configure the power converter; and a housing member that includes a cylindrical portion that is provided on a radially inner side of a magnetic circuit portion that includes the magnet portion and the armature winding, and to which the plurality of electrical components are disposed. The cylindrical portion is provided with a coolant passage through which a coolant flows. The plurality of electrical components are arranged in the housing member on a radially inner side of the cylindrical portion, in a circumferential direction along the cylindrical portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a longitudinal cross-sectional perspective view of a rotating electric machine; 
         FIG. 2  is a longitudinal cross-sectional view of the rotating electric machine; 
         FIG. 3  is a cross-sectional view taken along line in  FIG. 2 ; 
         FIG. 4  is a cross-sectional view showing a portion of  FIG. 3  in an enlarged manner; 
         FIG. 5  is an exploded view of the rotating electric machine; 
         FIG. 6  is an exploded view of an inverter unit; 
         FIG. 7  is a torque diagram of a relationship between ampere-turns of a stator winding and torque density; 
         FIG. 8  is a lateral cross-sectional view of a rotor and a stator; 
         FIG. 9  is a diagram showing a portion of  FIG. 8  in an enlarged manner; 
         FIG. 10  is a lateral cross-sectional view of the stator; 
         FIG. 11  is a longitudinal cross-sectional view of the stator; 
         FIG. 12  is a perspective view of the stator winding; 
         FIG. 13  is a perspective view of a configuration of a conductor; 
         FIG. 14  is a schematic diagram of a configuration of a wire; 
         FIG. 15  is a diagram of an aspect of the conductors in an nth layer; 
         FIG. 16  is a side view of the conductors in the nth layer and an n+1th layer; 
         FIG. 17  is a diagram of a relationship between electrical angle and magnetic flux density in a magnet according to an embodiment; 
         FIG. 18  is a diagram of the relationship between electrical angle and magnetic flux density in a magnet of a comparative example; 
         FIG. 19  is an electric circuit diagram of a control system of the rotating electric machine; 
         FIG. 20  is a functional block diagram of a current feedback control process performed by a control apparatus; 
         FIG. 21  is a functional block diagram of a torque feedback control process performed by the control apparatus; 
         FIG. 22  is a lateral cross-sectional view of a rotor and a stator according to a second embodiment; 
         FIG. 23  is a diagram showing a portion of  FIG. 22  in an enlarged manner; 
         FIG. 24  is a detailed diagram of a flow of magnetic flux in a magnet unit; 
         FIG. 25  is a cross-sectional view of the stator in a modification 1; 
         FIG. 26  is a cross-sectional view of the stator in the modification 1; 
         FIG. 27  is a cross-sectional view of the stator in a modification 2; 
         FIG. 28  is a cross-sectional view of the stator in a modification 3; 
         FIG. 29  is a cross-sectional view of the stator in a modification 4; 
         FIG. 30  is a lateral cross-sectional view of the rotor and the stator in a modification 7; 
         FIG. 31  is a functional block diagram of a part of a process performed by an operating signal generating unit in a modification 8; 
         FIG. 32  is a flowchart of the steps in a carrier frequency changing process; 
         FIG. 33  is a diagram of aspects of connection of conductors configuring a conductor group in a modification 9; 
         FIG. 34  is a diagram of a configuration in which four pairs of conductors are arranged in a laminated manner in the modification 9; 
         FIG. 35  is a lateral cross-sectional view of an inner-rotor-type rotor and stator in a modification 10; 
         FIG. 36  is a diagram showing a portion of  FIG. 35  in an enlarged manner; 
         FIG. 37  is a longitudinal cross-sectional view of an inner-rotor-type rotating electric machine; 
         FIG. 38  is a longitudinal cross-sectional view of an overall configuration of the inner-rotor-type rotating electric machine; 
         FIG. 39  is a diagram of a configuration of a rotating electric machine having an inner-rotor structure in a modification 11; 
         FIG. 40  is a diagram of the configuration of the rotating electric machine having an inner-rotor structure in the modification 11; 
         FIG. 41  is a diagram of a configuration of a revolving-armature-type rotating electric machine in a modification 12; 
         FIG. 42  is a cross-sectional view of a configuration of a conductor in a modification 14; 
         FIG. 43  is a diagram of a relationship among reluctance torque, magnet torque, and DM; 
         FIG. 44  is a diagram of teeth; 
         FIG. 45  is a perspective view of a vehicle wheel having an in-wheel-motor structure and a surrounding structure thereof; 
         FIG. 46  is a longitudinal cross-sectional view of the vehicle wheel and the surrounding structure thereof; 
         FIG. 47  is an exploded perspective view of the vehicle wheel; 
         FIG. 48  is a side view of a rotating electric machine viewed from a protruding side of a rotation shaft; 
         FIG. 49  is a cross-sectional view taken along line  49 - 49  in  FIG. 48 ; 
         FIG. 50  is a cross-sectional view taken along line  50 - 50  in  FIG. 49 ; 
         FIG. 51  is an exploded cross-sectional view of the rotating electric machine; 
         FIG. 52  is a partial cross-sectional view of a rotor; 
         FIG. 53  is a perspective view of a stator winding and a stator core; 
         FIG. 54  is a front view of the stator winding in a planarly expanded state; 
         FIG. 55  is a diagram of skewing of a conductor; 
         FIG. 56  is an exploded cross-sectional view of an inverter unit; 
         FIG. 57  is an exploded cross-sectional view of the inverter unit; 
         FIG. 58  is a diagram of a state of arrangement of electrical modules in an inverter housing; 
         FIG. 59  is a circuit diagram of an electrical configuration of a power converter; 
         FIG. 60  is a diagram of an example of a cooling structure of a switch module; 
         FIG. 61  is a diagram of an example of the cooling structure of the switch module; 
         FIG. 62  is a diagram of an example of the cooling structure of the switch module; 
         FIG. 63  is a diagram of an example of the cooling structure of the switch module; 
         FIG. 64  is a diagram of an example of the cooling structure of the switch module; 
         FIG. 65  is a diagram of an order of array of the electrical modules in relation to a cooling water passage; 
         FIG. 66  is a cross-sectional view taken along line  66 - 66  in  FIG. 49 ; 
         FIG. 67  is a cross-sectional view taken along line  67 - 67  in  FIG. 49 ; 
         FIG. 68  is a perspective view of a bus bar module alone; 
         FIG. 69  is a diagram of a state of electrical connection between the electrical modules and the bus bar module; 
         FIG. 70  is a diagram of a state of electrical connection between the electrical modules and the bus bar module; 
         FIG. 71  is a diagram of a state of electrical connection between the electrical modules and the bus bar module; 
         FIG. 72  is a configuration diagram for explaining a modification 1 of an in-wheel motor; 
         FIG. 73  is a configuration diagram for explaining a modification 2 of the in-wheel motor; 
         FIG. 74  is a configuration diagram for explaining a modification 3 of the in-wheel motor; 
         FIG. 75  is a configuration diagram for explaining a modification 4 of the in-wheel motor; 
         FIG. 76  is a configuration diagram of a state of arrangement of the electrical modules in a modification 5 of the in-wheel motor; 
         FIG. 77  is a diagram of a configuration of a comparative example; 
         FIG. 78  is a diagram of a relationship between current and amount of heat generation in a capacitor; 
         FIG. 79  is a diagram of frequency characteristics of a current amplification factor of a capacitor module; 
         FIG. 80  is a diagram of a configuration of a modification 1 related to the arrangement of the electrical modules; 
         FIG. 81  is a diagram of a configuration of a modification 2 related to the arrangement of the electrical modules; 
         FIG. 82  is a diagram of a configuration of a modification 3 related to the arrangement of the electrical modules; and 
         FIG. 83  is a diagram of a circuit configuration of another switch module. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     For example, JP-A-2013-176202 describes an in-wheel motor in which an outer-rotor-type rotating electric machine is used. In the in-wheel motor, an outer-rotor-type motor that includes a stator and a rotor is housed inside a wheel. The stator is fixed to an inner frame on an inner side thereof, and the rotor is supported so as to be capable of rotating integrally with the wheel. In addition, the inner frame is provided in an annular shape so as to surround a shaft and is configured such that a bearing is interposed between the inner frame and the shaft. 
     For example, in an electric vehicle that uses a rotating electric machine as a power source, a rotating electric machine that achieves high efficiency and enables size reduction is needed. There is still room for technical improvement regarding this need. 
     It is thus desired to provide a rotating electric machine that enables high efficiency and size reduction, and a vehicle wheel in which the rotating electric machine is used. 
     A plurality of embodiments disclosed in this specification employ technical measures that differ from one another to achieve respective objects. Objects, features, and effects disclosed in this specification will be further clarified with reference to detailed descriptions that follow and accompanying drawings. 
     A first exemplary embodiment provides a rotating electric machine that includes: a field element that includes a magnet portion that includes a plurality of magnetic poles of which polarities alternate in a circumferential direction; an armature that includes an armature winding of multiple phases; and a power converter that is electrically connected to the armature winding. Either of the field element and the armature rotating together with a rotation shaft. 
     The rotating electric machine includes: a plurality of electrical components that configure the power converter; and a housing member that includes a cylindrical portion that is provided on a radially inner side of a magnetic circuit portion that includes the magnet portion and the armature winding, and to which the plurality of electrical components are disposed. The cylindrical portion is provided with a coolant passage through which a coolant flows. The plurality of electrical components are arranged in the housing member on a radially inner side of the cylindrical portion, in a circumferential direction along the cylindrical portion. 
     In the above-described configuration, the cylindrical portion of the housing member is arranged on the radially inner side of the magnetic circuit portion that includes the magnet portion and the armature winding. The coolant passage through which a coolant flows is formed in the cylindrical portion. 
     In addition, a plurality of electrical components are arranged on the radially inner side of the cylindrical portion in the circumferential direction along the cylindrical portion. As a result, the magnetic circuit portion, a cooling portion, and the power converter can be arranged so as to be laminated in the radial direction of the rotating electric machine. An efficient component arrangement can be achieved while reduction of dimension in the axial direction is achieved. Consequently, high efficiency and size reduction can be implemented in the rotating electric machine. 
     According to a second exemplary embodiment, in the first exemplary embodiment, the plurality of electrical components are a plurality of electrical modules that includes a heat generating component that generates heat as a result of energization being housed in a housing case. The electrical module is provided so as to be in contact with an inner circumferential surface of the cylindrical portion. 
     In the above-described configuration, the plurality of electrical components are configured as electrical modules that include heat generating components. In addition, as a result of the electrical modules being provided so as to be in contact with the inner circumferential surface of the cylindrical portion, heat from the electrical modules is transmitted to the cylindrical portion. The electrical modules are suitably cooled as a result of heat exchange in the cylindrical portion. 
     According to a third exemplary embodiment, in the first exemplary embodiment, the plurality of electrical components are a plurality of electrical modules that includes a heat generating component that generate heat as a result of energization being housed in a housing case. The plurality of electrical modules include a switch module that includes a semiconductor switching element as the heat generating component. The switch module is provided so as to be in contact with an inner circumferential surface of the cylindrical portion. 
     In the above-described configuration, the plurality of electrical components are configured to include the switch module that includes the semiconductor switching element that is the heat generating component. In addition, as a result of the switch module being provided so as to be in contact with the inner circumferential surface of the cylindrical portion, heat from the switch module is transmitted to the cylindrical portion. The switch module is suitably cooled as a result of heat exchange in the cylindrical portion. 
     According to a fourth exemplary embodiment, in the third exemplary embodiment, the power converter includes a serial-connection body of an upper arm switch and a lower arm switch that is provided for each phase of the armature winding, and a capacitor that is connected in parallel to each serial-connection body for each phase. The switch module includes the switching elements that configure the upper arm switch and the lower arm switch, and the capacitor as the heat generating components. 
     In addition, the switch module includes a cooling apparatus that cools the semiconductor switching elements and the capacitor by supplying the coolant from the coolant passage into a module interior. In the switch module, coolers that configure the cooling apparatus are arranged on both sides sandwiching the semiconductor switching element, and the capacitor is arranged on a side opposite the semiconductor switching element of at least either of the coolers on both sides of the semiconductor switching element. 
     As a result of the above-described configuration, in the switch module, because the coolers are arranged on both sides of the semiconductor switching element, cooling performance regarding the semiconductor switching element can be improved. In addition, because not only the semiconductor switching element but also the capacitor is provided near the cooler, cooling performance regarding the capacitor can also be improved. 
     According to a fifth exemplary embodiment, in the third exemplary embodiment, the power converter includes: a serial-connection body of an upper arm switch and a lower arm switch that is provided for each phase of the armature winding; a drive circuit that drives the upper arm switch and the lower arm switch; and a capacitor that is connected in parallel to each serial-connection body for each phase. The switch module includes the switching elements that configure the upper arm switch and the lower arm switch, the drive circuit, and the capacitor as the heat generating components. 
     In addition, the switch module includes a cooling apparatus that cools the semiconductor switching elements and the capacitor by supplying the coolant from the coolant passage into a module interior. In the switch module, coolers that configure the cooling apparatus is arranged on both sides sandwiching the semiconductor switching element. In addition, the drive circuit is arranged on a side opposite the semiconductor switching element of one of the coolers on both sides of the switching element, and the capacitor is arranged on a side opposite the semiconductor switching element of the other cooler. 
     As a result of the above-described configuration, in the switch module, because the coolers are arranged on both sides of the semiconductor switching element, cooling performance regarding the semiconductor switching element can be improved. In addition, because not only the semiconductor switching element but also the driver and the capacitor are provided near the cooler, cooling performance regarding the driver and the capacitor can also be improved. 
     According to a sixth exemplary embodiment, in the second exemplary embodiment or the third exemplary embodiment, the electrical module includes a cooling apparatus that cools the heat generating component by supplying the coolant from the coolant passage into a module interior. 
     As a result of the above-described configuration, the coolant is supplied from the coolant passage into the electrical module and the heat generating component is cooled by the cooling apparatus. In this case, the electrical module is cooled by heat exchange in the cooling apparatus, in addition to heat exchange in the cylindrical portion. Consequently, cooling effect of the electrical module can be improved. 
     According to a seventh exemplary embodiment, in any one of the second to sixth exemplary embodiments, the plurality of electrical modules includes a switch module that includes a semiconductor switching element that is the heat generating component and a capacitor module that includes a smoothing capacitor ( 606 ) that is the heat generating component. The switch module and the capacitor module are provided so as to be in contact with the inner circumferential surface of the cylindrical portion. 
     In the above-described configuration, the plurality of electrical modules are configured to include the switch module that includes the semiconductor switching element and the capacitor module that includes the smoothing capacitor. In addition, because the switch module and the capacitor module are provided so as to be in contact with the inner circumferential surface of the cylindrical portion, heat from the switch module and the capacitor module are transmitted to the cylindrical portion. The switch module and the capacitor module are suitably cooled by heat exchange in the cylindrical portion. 
     Here, the switch module and the capacitor module are provided as the plurality of electrical modules. In this configuration, a cooling apparatus may be provided in at least the switch module, of the switch module and the capacitor module. The cooling apparatus cools the heat generating component by supplying the coolant from the coolant passage into a module interior 
     According to an eighth exemplary embodiment, in the seventh exemplary embodiment, the rotating electric machine is such that the coolant flows into the coolant passage from a coolant recirculation system that includes a coolant recirculation path that recirculates the coolant and a heat releasing apparatus that is provided on the coolant recirculation path. 
     The coolant passage has an inlet portion into which the coolant flows from the coolant recirculation path and an outlet portion from which the coolant flows into the coolant recirculation path. The coolant passage is provided in an annular shape along the cylindrical portion so as to connect the inlet portion and the outlet portion in the circumferential direction. The switch module is arranged on an upstream side close to the inlet portion on the coolant passage and the capacitor module is arranged further towards a downstream side than the switch module is. 
     As a result of the above-described configuration, the coolant flows from the coolant recirculation path into a coolant passage that is provided in the cylindrical portion of the housing member, through the inlet portion. In addition, the coolant flows into the coolant recirculation path through the outlet portion. At this time, cooling of the switch module and the capacitor module by the coolant is performed during a period in which the coolant reaches the outlet portion from the inlet portion. 
     In this case, under an assumption that the switch module is arranged on the upstream side of the coolant passage, the capacitor module is arranged on the downstream side of the coolant passage, and the coolant that flows through the coolant passage is lower in temperature towards the upstream side, a configuration in which the switch module is preferentially cooled can be implemented. 
     According to a ninth exemplary embodiment, in the seventh exemplary embodiment, the rotating electric machine is such that the coolant flows into the coolant passage from a coolant recirculation system that includes a coolant recirculation path that recirculates the coolant and a heat releasing apparatus that is provided on the coolant recirculation path. 
     The coolant passage has an inlet portion into which the coolant flows from the coolant recirculation path and an outlet portion from which the coolant flows into the coolant recirculation path. The coolant passage is provided in an annular shape along the cylindrical portion so as to connect the inlet portion and the outlet portion in the circumferential direction. The cylindrical portion is provided with a protruding portion that protrudes on a radially inner side. The inlet portion and the outlet portion are provided in the protruding portion. 
     As intervals between the electrical modules that are adjacent to each other in the circumferential direction, a first interval (INTI) and a second interval (INT 2 ) that is wider than the first interval are provided. The protruding portion is provided in a portion in which the interval between the electrical modules that are adjacent to each other in the circumferential direction is the second interval. 
     As a result of the above-described configuration, the coolant flows from the coolant recirculation path into a coolant passage that is provided in the cylindrical portion of the housing member, through the inlet portion. In addition, the coolant flows into the coolant recirculation path through the outlet portion. At this time, cooling of the switch module and the capacitor module by the coolant is performed during a period in which the coolant reaches the outlet portion from the inlet portion. 
     In addition, in the above-described configuration, a portion of the intervals between the electrical modules that are adjacent to each other in the circumferential direction is widened. The protruding portion is provided in the portion that is the widened interval (second interval). Therefore, the inlet portion and the outlet portion of a coolant passage can be suitably formed in a portion that is on the radially inner side of the cylindrical portion. 
     That is, an amount of circulation of the coolant is required to be ensured to improve cooling performance. Therefore, increasing opening areas of the inlet portion and the outlet portion can be considered. In this regard, as a result of a portion of the intervals between the electrical modules being widened as described above, the inlet portion and the outlet portion of a desired size can be suitably formed. 
     According to a tenth exemplary embodiment, in the ninth exemplary embodiment, a terminal module that is connected to an electrical input/output terminal that is provided for each electrical module is provided. The terminal module has an external connection terminal that enables electrical connection with an external apparatus outside the rotating electric machine. The external connection terminal is arranged in a position that is arrayed with the protruding portion in the radial direction on the radially inner side of the cylindrical portion. 
     As a result of the above-described configuration, the terminal module is connected to each of the plurality of electrical modules. Electrical connection between each electrical module and an external apparatus outside the rotating electric machine can be achieved through the external connection terminal of the terminal module. In addition, the external connection terminal is arranged in apposition that is arrayed with the protruding portion in the radial direction on the radially inner side of the cylindrical portion. 
     That is, the external connection terminal is arranged together with the protruding portion in the portion in which the interval between the electrical modules that are adjacent to each other in the circumferential direction is widened (the portion corresponding to the second interval). Consequently, the external connection terminal can be suitably arranged while interference with the electrical modules is prevented. 
     According to an eleventh exemplary embodiment, in the ninth exemplary embodiment or the tenth exemplary embodiment, the switch module is arranged on an upstream side close to the inlet portion on the coolant passage and the capacitor module is arranged further towards a downstream side than the switch module is. 
     As a result of the above-described configuration, the switch module is arranged on the upstream side of the coolant passage and the capacitor module is arranged on the downstream side of the coolant passage. In this case, because the coolant that flows through the coolant passage is lower in temperature towards the upstream side, a configuration in which the switch module is preferentially cooled can be implemented. 
     According to a twelfth exemplary embodiment, in any one of the second to sixth exemplary embodiments, the power converter converts electric power between a direct-current power supply and a phase winding of each phase of the armature winding. As the plurality of electrical modules, a plurality of switch modules that include a switching element that controls an energization direction of a current that flows to the phase winding of each phase from the direct-current power supply by a switching operation, and a plurality of capacitor modules that include a smoothing capacitor that suppresses high-frequency vibrations that are generated in the current as a result of the switching operation are provided. 
     A positive-electrode-side conductor that is connected to a positive-electrode side of the direct-current power supply and a negative-electrode-side conductor that is connected to a negative-electrode side of the direct-current power supply are provided. The switching element and the smoothing capacitor are connected in parallel between the positive-electrode-side conductor and the negative-electrode-side conductor. The plurality of switch modules and the plurality of capacitor modules are arranged in an annular shape. 
     The positive-electrode-side conductor and the negative-electrode-side conductor form an annular shape and are connected to a terminal of each module in an order of array of the switch modules and the capacitor modules in the circumferential direction. The capacitor modules are arranged on both sides of the switch module, and capacitances of the smoothing capacitors included in the capacitor modules arranged on both sides thereof are equal to each other. 
     In the power converter that is provided integrally with the rotating electric machine, when the plurality of switch modules and the plurality of capacitor modules are arranged in an annular shape, and the positive-electrode-side terminal and the negative-electrode-side terminal are formed in an annular shape in correspondence thereto, amounts of heat generation in the capacitor modules may become imbalanced based on the order of array of the modules in the circumferential direction. 
     In this regard, in the above-described configuration, the capacitor modules are arranged on both sides of each switch module. In addition, the capacitances of the capacitors included in the capacitor modules that are arranged on both sides are equal to each other. As a result of this configuration, approximately equal currents flow from each switch module to the smoothing capacitors on both sides of which the capacitances are equal. Therefore, the amounts of heat generation in the capacitor modules can be equalized. The imbalance in the amounts of heat generation in the capacitor modules can be suppressed. 
     As a result of the imbalance in the amounts of heat generation in the capacitor modules being suppressed, cooling capabilities imparted to the rotating electric machine can be reduced, and actualization of size reduction that accompanies the reduction in cooling capabilities can be expected. Here, the switching element and the smoothing capacitor correspond to heat generating components. 
     According to a thirteenth exemplary embodiment, in the twelfth exemplary embodiment, the plurality of switch modules and the plurality of capacitor modules are arranged such that the switch module and the capacitor module are alternately arrayed in the circumferential direction. 
     As a result of the above-described configuration, the number of capacitor modules required in the power converter can be reduced while the currents that flow to the capacitors that is included in the capacitor modules are equalized. Configuration of the power converter can be simplified. 
     According to a fourteenth exemplary embodiment, as in the twelfth exemplary embodiment, in the plurality of switch modules and the plurality of capacitor modules that are arrayed in the circumferential direction, two capacitor modules each are arranged between the switch modules that are distributively arranged in the circumferential direction. The two capacitor modules are connected to the positive-electrode-side conductor and the negative-electrode-side conductor in differing connection positions. 
     As a result of the above-described configurations, the switch modules are not arranged on both sides of each capacitor module. Therefore, currents flowing to the capacitor that is included in the capacitor module from the switch modules on both sides and excessive current flowing to the capacitor can be suppressed. 
     According to a fifteenth exemplary embodiment, in the twelfth exemplary embodiment, in the plurality of switch modules and the plurality of capacitor modules that are arrayed in the circumferential direction , two or more capacitor modules each are arranged between the switch modules that are distributively arranged in the circumferential direction, and the two or more capacitor modules are connected to the positive-electrode-side conductor and the negative-electrode-side conductor in a same connection position. 
     As a result of the above-described configuration, as a result of the connection positions being the same, even if two or more capacitor modules are arranged between the switching modules that area adjacent to each other in the circumferential direction, the currents can be equally supplied to the capacitor modules. Imbalance in the amount of heat generation in the capacitor modules can be suppressed. 
     According to a sixteenth exemplary embodiment, in any of the twelfth to fifteenth exemplary embodiments, in the positive-electrode-side conductor and the negative-electrode-side conductor, connection positions with the terminals of the switch module and the capacitor module are arranged at equal intervals in the circumferential direction. 
     As a result of the above-described configuration, when viewed from each switch module, impedances of the capacitors that are included in the capacitor modules on both side can be made equal. As a result, the currents that flow to the capacitors can be made equal. Imbalance in the amount of heat generation in the capacitor modules can be suppressed. 
     According to a seventeenth exemplary embodiment, in the twelfth exemplary embodiment, on a virtual circle on which the plurality of switch modules and the plurality of capacitor modules are arrayed, an expanded portion (EX) in which an interval between adjacent modules is more expanded than others is provided. The capacitor modules are arranged on both sides sandwiching the expanded portion. 
     In the rotating electric machine, for example, a portion of the coolant passage being provided on the inner circumferential side of the cylindrical portion (that is, on the virtual circle on which the modules are arrayed) can be considered. In this case, the expanded portion in which the interval between the modules that are adjacent to each other is more expanded than others may be provided. 
     In this case, when the switch module is arranged on one side of the expanded portion in the circumferential direction, and either of the capacitor modules that are arranged on both sides of the switch module is arranged on the other side of the expanded portion in the circumferential direction, the current flows from the switch module so as to be concentrated in the other capacitor module, that is the capacitor module that is arranged on the side opposite the expanded portion, and an imbalance occurs in the amounts of heat generation in the capacitor modules. 
     In this regard, in the above-described configuration, the capacitor modules are arranged on both sides sandwiching the expanded portion. Therefore, even when the expanded portion is provided, imbalance occurring in the amounts of heat generation in the capacitor modules can be suppressed. 
     According to an eighteenth exemplary embodiment, in any one of the first to seventeenth exemplary embodiment, the rotating electric machine is an outer-rotor-type rotating electric machine in which a rotor that serves as the field element is provided on a radially outer side of a stator that serves as the armature. The stator is fixed on a radially outer side of the cylindrical portion. 
     In the outer-rotor-type rotating electric machine, the stator is fixed on the radially outer side of the cylindrical portion, and a plurality of electrical components (electrical modules) are arranged on the radially inner side. As a result, heat from the stator is transmitted to the cylindrical portion from the radially outer side. 
     In addition, heat from the electrical components is transmitted to the cylindrical portion from the radially inner side. In this case, the stator and the electrical components can be simultaneously cooled by the coolant that flows through the coolant passage. The heat from the heat generating components in the rotating electric machine can be effectively released. 
     According to a nineteenth exemplary embodiment, in the eighteenth exemplary embodiment, the electrical components on the radially inner side and the armature winding on the radially outer side with the cylindrical portion therebetween are electrically connected by a connection line. The connection line is provided in a position that is away from the coolant passage, to one side or another side in the axial direction. 
     In the above-described configuration, in the rotating electric machine, the electrical components and the armature winding are respectively provided in an area on the radially inner side and an area on the radially outer side with the cylindrical portion therebetween. However, the electrical components and the armature winding are electrically connected by the connection line. 
     In this case, the connection line is provided in a position that is away from the coolant passage, to one side or the other side in the axial direction. Even when the coolant passage is formed in an annular shape in the cylindrical portion, that is, the inner side and the outer side of the cylindrical portion is divided by the coolant passage, the electrical components and the armature winding can be suitably connected. 
     According to a twentieth exemplary embodiment, in any one of the first to nineteenth exemplary embodiments, the armature winding includes conductor portions that are arranged at predetermined intervals in the circumferential direction in a position opposing the magnet portion. 
     In the armature, a configuration is such that a conductor-to-conductor member is provided between the conductor portions in the circumferential direction, and when a width dimension in the circumferential direction of the conductor-to-conductor member in a single magnetic pole is Wt, a saturation magnetic density of the conductor-to-conductor member is Bs, a width dimension in the circumferential direction of the magnet portion in a single magnetic pole is Wm, and a residual magnetic flux density of the magnet portion is Br, a magnetic material in which a relationship expressed by Wt x Bs &lt;Wm x Br is satisfied, or a non-magnetic material is used as the conductor-to-conductor member. 
     Alternatively, the conductor-to-conductor member may not be provided between the conductor portions in the circumferential direction. A thickness dimension of the conductor portion in the radial direction thereof is less than a width dimension in the circumferential direction amounting to a single phase within a single magnetic pole. 
     In the rotating electric machine configured as described above, as a result of the teeth (core) between the conductor portions that are arrayed in the circumferential direction in the armature being made smaller or eliminated, torque restrictions attributed to magnetic saturation that occurs between the conductor portions are suppressed and torque decrease is suppressed by the conductor portion being a thin, flat type. 
     In this case, even if outer diameter dimensions of the rotating electric machine are the same, as a result of the armature being made thinner, an area on the radially inner side of the magnetic circuit portion can be expanded. The cylindrical portion that includes the coolant passage and the plurality of electrical components that are provided on the radially inner side of the cylindrical portion can be suitably arranged using the inner area. 
     According to a twenty-first exemplary embodiment, in the twentieth exemplary embodiment, the magnet portion is configured to be oriented such that, on a side of a d-axis that is a magnetic pole center, an orientation of an easy axis of magnetization is parallel to the d-axis compared to a side of a q-axis that is a magnetic pole boundary. 
     In the rotating electric machine configured as described above, magnet magnetic flux on the d-axis is reinforced by the magnet magnetic flux being concentrated on the d-axis side in the magnet portion. Torque enhancement that accompanies the reinforcement of the magnet magnetic flux can be achieved. 
     In this case, in accompaniment with a thickness dimension in the radial direction of the magnet portion being able to be made smaller (thinner), the area on the radially inner side of the magnetic circuit portion can be expanded. The cylindrical portion that includes the coolant passage and the plurality of electrical components that are provided on the radially inner side of the cylindrical portion can be suitably arranged using the inner area. Here, as a result of increased thinness on the armature side also being achieved, the effect becomes even more prominent. 
     A twenty-second means is a vehicle wheel in which the rotating electric machine according to any one of the first to twenty-first means is used as an in-wheel motor. A base plate is fixed to the housing member of the rotating electric machine. In addition, a mounting mechanism mounts the vehicle wheel to a vehicle body, and is attached to the base plate. 
     The vehicle wheel in which the rotating electric machine configured as described above is used as an in-wheel motor is mounted to the vehicle body by the base plate that is fixed to the housing member and a mounting mechanism, such as a suspension apparatus. Here, because size reduction is implemented in the rotating electric machine, space saving can be achieved even when assembly to a vehicle body is required. Therefore, an advantageous configuration in terms of increasing an installation area of a power supply apparatus, such as a battery, or increasing vehicle cabin space in the vehicle can be implemented. 
     A plurality of embodiments will be described with reference to the drawings. According to the plurality of embodiments, sections that are functionally and/or structurally corresponding and/or related may be given the same reference numbers or reference numbers of which digits in the hundreds place and higher differ. Descriptions according to other embodiments can be referenced regarding the corresponding sections and/or related sections. 
     For example, a rotating electric machine according to a present embodiment is used as a vehicle power source. However, the rotating electric machine can be widely used for industrial use, in vehicles, household appliances, office automation (OA) equipment, and game machines, and the like. Here, sections according to the embodiments below that are identical or equivalent to each other are given the same reference numbers in the drawings. Descriptions of sections that have the same reference numbers are applicable therebetween. 
     First Embodiment 
     A rotating electric machine  10  according to a present embodiment is a synchronous-type multiphase alternating-current motor and has an outer-rotor structure (outer-revolution structure). An overview of the rotating electric machine  10  is shown in  FIG. 1  to  FIG. 5 . 
       FIG. 1  is a longitudinal cross-sectional perspective view of the rotating electric machine  10 .  FIG. 2  is a longitudinal cross-sectional view of the rotating electric machine  10  in a direction along a rotation shaft  11 .  FIG. 3  is a lateral cross-sectional view (cross-sectional view taken along line III-III in  FIG. 2 ) of the rotating electric machine  10  in a direction orthogonal to the rotation shaft  11 .  FIG. 4  is a cross-sectional view showing a portion of  FIG. 3  in an enlarged manner.  FIG. 5  is an exploded view of the rotating electric machine  10 . 
     Here, in  FIG. 3 , for the purpose of illustration, the rotation shaft  11  is omitted and hatching that indicates a cross-sectional plane is omitted. In the description below, a direction in which the rotation shaft  11  extends is an axial direction. A direction that radially extends from a center of the rotation shaft  11  is a radial direction. A direction that circumferentially extends with the rotation shaft  11  as a center is a circumferential direction. 
     The rotating electric machine  10  generally includes a bearing unit  20 , a housing  30 , a rotor  40 , a stator  50 , and an inverter unit  60 . The rotating electric machine  10  is configured by all of these members being arranged coaxially with the rotation shaft  11  and assembled in the axial direction in a predetermined order. The rotating electric machine  10  according to the present embodiment is configured to include the rotor  40  that serves as a “field element” and the stator  50  that serves as an “armature.” The rotating electric machine  10  is implemented as a revolving-field-type rotating electric machine. 
     The bearing unit  20  includes two bearings  21  and  22 , and a holding member  23 . The two bearings  21  and  22  are arranged so as to be separated from each other in the axial direction. The holding member  23  holds the bearings  21  and  22 . For example, the bearings  21  and  22  are radial ball bearings. Each of the bearings  21  and  22  includes an outer ring  25 , an inner ring  26 , and a plurality of balls  27  that are arranged between the outer ring  25  and the inner ring  26 . The holding member  23  has a circular cylindrical shape. The bearings  21  and  22  are assembled on a radially inner side of the holding member  23 . In addition, the rotation shaft  11  and the rotor  40  are supported so as to freely rotate on a radially inner side of the bearings  21  and  22 . The bearings  21  and  22  configure a set of bearings that rotatably support the rotation shaft  11 . 
     In each of the bearings  21  and  22 , the balls  27  are held by a retainer (not shown). In this state, a pitch between the balls is maintained. The bearings  21  and  22  have a sealing member in upper and lower portions in the axial direction of the retainer, and an interior thereof is filled with a non-conductive grease (such as a non-conductive urea-based grease). In addition, a position of the inner ring  26  is mechanically held by a spacer. A constant-pressure preload that projects in an up/down direction from an inner side is applied. 
     The housing  30  includes a peripheral wall  31  that forms a circular cylindrical shape. The peripheral wall  31  has a first end and a second end that are opposing in the axial direction thereof. The peripheral wall  31  has an end surface  32  in the first end and an opening  33  in the second end. The opening  33  is open over the overall second end. A circular hole  34  is formed in a center of the end surface  32 . The bearing unit  20  is fixed by a fixture, such as a screw or a rivet, in a state in which the bearing unit  20  is inserted into the hole  34 . In addition, the rotor  40  that has a hollow circular cylindrical shape and the stator  50  that has a hollow circular cylindrical shape are housed inside the housing  30 , that is, in an interior space that is demarcated by the peripheral wall  31  and the end surface  32 . 
     According to the present embodiment, the rotating electric machine  10  is an outer-rotor type. Inside the housing  30 , the stator  50  is arranged on a radially inner side of the rotor  40  that has the cylindrical shape. The rotor  40  is supported in a cantilevered manner by the rotation shaft  11  on the end surface  32  side in the axial direction. 
     The rotor  40  includes a magnet holder  41  that is formed into a hollow cylindrical shape and an annular magnet unit  42  that is provided on a radially inner side of the magnet holder  41 . The magnet holder  41  has an approximately cup-like shape and functions as a magnet holding member. The magnet holder  41  includes a circular cylindrical portion  43 , a fixing portion (attachment)  44 , and an intermediate portion  45 . The circular cylindrical portion  43  has a circular cylindrical shape. 
     The fixing portion  14  also has a circular cylindrical shape and has a smaller diameter than the circular cylindrical portion  43 . The intermediate portion  45  is a portion that connects the circular cylindrical portion  43  and the fixing portion  44 . The magnet unit  42  is attached to an inner circumferential surface of the circular cylindrical portion  43 . 
     Here, the magnet holder  41  is made of a cold-rolled steel sheet (steel plate cold commercial [SPCC]), a forging steel, a carbon fiber-reinforced plastic (CFRP), or the like that has sufficient mechanical strength. 
     The rotation shaft  11  is inserted into a through hole  44   a  in the fixing portion  44 . The fixing portion  44  is fixed to the rotation shaft  11  that is arranged inside the through hole  44   a . That is, the magnet holder  41  is fixed to the rotation shaft  11  by the fixing portion  44 . Here, the fixing portion  44  may be fixed to the rotation shaft  11  by spline coupling or key coupling that uses recesses and protrusions, welding, crimping, or the like. As a result, the rotor  40  rotates integrally with the rotation shaft  11 . 
     In addition, the bearings  21  and  22  of the bearing unit  20  are assembled on a radially outer side of the fixing portion  44 . As described above, the bearing unit  20  is fixed to the end surface  32  of the housing  30 . Therefore, the rotation shaft  11  and the rotor  40  are rotatably supported by the housing  30 . As a result, the rotor  40  can freely rotate inside the housing  30 . 
     The fixing portion  44  is provided in the rotor  40  in only one of two end portions that are opposing in the axial direction of the rotor  40 . As a result, the rotor  40  is supported by the rotation shaft  11  in a cantilevered manner. Here, the fixing portion  44  of the rotor  40  is rotatably supported at two positions that differ in the axial direction, by the bearings  21  and  22  of the bearing unit  20 . 
     That is, the rotor  40  is rotatably supported by the two bearings  21  and  22  that are separated in the axial direction of the rotor  40 , in one of two end portions of the magnet holder  41  that are opposing in the axial direction of the magnet holder  41 . Therefore, even in a structure in which the rotor  40  is supported by the rotation shaft  11  in a cantilevered manner, stable rotation of the rotor  40  is implemented. In this case, the rotor  40  is supported by the bearings  21  and  22  at positions that are shifted to one side in relation to a center position in the axial direction of the rotor  40 . 
     In addition, a dimension of a gap between the outer ring  25  and the inner ring  26 , and the balls  27  differ between the bearing  22  of the bearing unit  20  that is closer to a center of the rotor  40  (lower side in the drawing) and the bearing  21  on a side opposite thereof (upper side in the drawing). For example, the gap dimension is greater in the bearing  22  that is closer to the center of the rotor  40  than in the bearing  21  on the side opposite thereof. In this case, even when shaking of the rotor  40  or vibrations caused by imbalance attributed to component tolerance act on the bearing unit  20  on the side that is closer to the center of the rotor  40 , effects of the shaking and the vibrations are favorably absorbed. Specifically, a play dimension (gap dimension) is increased by a preload in the bearing  22  that is closer to the center of the rotor  40  (lower side in the drawing). 
     As a result, the vibrations that occur in the cantilevered-support structure are absorbed by the play portion. The preload may be either of a fixed-position preload and a constant-pressure preload. In the case of the fixed-position preload, the outer rings  25  of the bearing  21  and the bearing  22  are both joined to the holding member  23  using a method such as press-fitting or bonding. 
     In addition, the inner rings  26  of the bearing  21  and the bearing  22  are both joined to the rotation shaft  11  using a method such as press-fitting or bonding. Here, the preload can be generated by the outer ring  25  of the bearing  21  being arranged in a position that differs in the axial direction from that of the inner ring  26  of the bearing  21 . The preload can also be generated by the outer ring  25  of the bearing  22  being arranged in a position that differs in the axial direction from that of the inner ring  26  of the bearing  22 . 
     Furthermore, in a case in which the constant-pressure preload is used, a preload spring, such as wave washer  24 , is arranged in an area that is sandwiched between the bearing  22  and the bearing  21  so that the preload is generated in the axial direction from the same area that is sandwiched between the bearing  22  and the bearing  21 , towards the outer ring  25  of the bearing  22 . In this case as well, the inner rings  26  of the bearing  21  and the bearing  22  are both joined to the rotation shaft  11  using a method such as press-fitting or bonding. The outer ring  25  of the bearing  21  or the bearing  22  is arranged with a predetermined clearance between the outer ring  25  and the holding member  23 . 
     As a result of a configuration such as this, a spring force of the preload spring acts on the outer ring  25  of the bearing  22  in a direction away from the bearing  21 . In addition, as a result of this force being transmitted to the rotation shaft  11 , a force that presses the inner ring  26  of the bearing  21  in the direction of the bearing  22  is applied. As a result, in both the bearings  21  and  22 , the positions of the outer ring  25  and the inner ring  26  in the axial direction are shifted. The preload can be applied to the two bearings in a manner similar to the above-described fixed-position preload. 
     Here, when the constant-pressure preload is generated, the spring force is not necessarily required to be applied to the outer ring  25  of the bearing  22  as shown in  FIG. 2 . For example, the spring force may be applied to the outer ring  25  of the bearing  21 . In addition, the inner ring  26  of either of the bearings  21  and  22  may be arranged with a predetermined clearance between the inner ring  26  and the rotation shaft  11 . The outer rings  25  of the bearings  21  and  22  may be joined to the holding member  23  using a method such as press-fitting or bonding, and the preload may thereby be applied to the two bearings. 
     Furthermore, when force is applied such that the inner ring  26  of the bearing  21  separates from the bearing  22 , force is preferably applied such that the inner ring  26  of the bearing  22  separates from the bearing  21  as well. Conversely, when force is applied such that the inner ring  26  of the bearing  21  approaches the bearing  22 , force is preferably applied such that the inner ring  26  of the bearing  22  approaches the bearing  21  as well. 
     Here, when the present rotating electric machine  10  is applied to a vehicle for the purpose of a vehicle power source or the like, vibrations that have components in a direction which the preload is generated may be applied to a mechanism that generates the preload, or a direction of gravitational force that is applied to a target to which the preload is applied may change. Therefore, when the present rotating electric machine  10  is applied to a vehicle, the fixed-position preload is preferably used. 
     In addition, the intermediate portion  45  includes an annular inner shoulder portion  49   a  and an annular outer shoulder portion  49   b . The outer shoulder portion  49   b  is positioned on an outer side of the inner shoulder portion  49   a  in the radial direction of the intermediate portion  45 . The inner shoulder portion  49   a  and the outer shoulder portion  49   b  are separated from each other in the axial direction of the intermediate portion  45 . 
     As a result, the circular cylindrical portion  43  and the fixing portion  44  partially overlap in the radial direction of the intermediate portion  45 . That is, the circular cylindrical portion  43  protrudes further towards the outer side in the axial direction than a base end portion (a rear-side end portion on the lower side of the drawing) of the fixing portion  44 . In the present configuration, the rotor  40  can be supported to the rotation shaft  11  in a position that is closer to the center of gravity of the rotor  40 , compared to a case in which the intermediate portion  45  is provided in a planar shape without a step. Stable operation of the rotor  40  can be implemented. 
     In the above-described configuration of the intermediate portion  45 , a bearing-housing recessing portion  46  that houses a portion of the bearing unit  20  is formed in the rotor  40  in an annular shape, in a position surrounding the fixing portion  44  in the radial direction and towards an inner side of the intermediate portion  45 . In addition, a coil-housing recessing portion  47  that houses a coil end  54  of a stator winding  51  of the stator  50 , described hereafter, is formed in the rotor  40  in a position surrounding the bearing-housing recessing portion  46  in the radial direction and towards an outer side of the intermediate portion  45 . 
     Furthermore, the housing recessing portions  46  and  47  are arranged so as to be adjacent to each other on the inner side and the radially outer side. That is, a portion of the bearing unit  20  and the coil end  54  of the stator winding  51  are arranged so as to overlap on the inner side and the radially outer side. As a result, a length dimension in the axial direction of the rotating electric machine  10  can be shortened. 
     The intermediate portion  45  is provided so as to protrude towards the radially outer side from the rotation shaft  11  side. In addition, a contact preventing portion that extends in the axial direction and prevents contact with the coil end  54  of the stator winding  51  of the stator  50  is provided in the intermediate portion  45 . The intermediate portion  45  corresponds to a protruding portion. 
     An axial-direction dimension of the coil end  54  can be decreased and an axial length of the stator  50  can be shortened by the coil end  54  being bent towards the inner side or the radially outer side. The bending direction of the coil end  54  may be that which takes into consideration assembly with the rotor  40 . 
     When assembly of the stator  50  on the radially inner side of the rotor  40  is assumed, the coil end  54  may be bent towards the radially inner side on an insertion-end side in relation to the rotor  40 . The bending direction of a coil end on a side opposite the coil end  54  may be arbitrary. However, in terms of manufacturing, a shape in which the coil end is bent towards the outer side that has spatial leeway is preferable. 
     In addition, the magnet unit  42  that serves as a magnet portion is configured by a plurality of permanent magnets that are arranged on the radially inner side of the circular cylindrical portion  43  such that polarities alternately change along the circumferential direction. As a result, the magnet unit  42  has a plurality of magnetic poles in the circumferential direction. However, details of the magnet unit  42  will be described hereafter. 
     The stator  50  is provided on the radially inner side of the rotor  40 . The stator  50  includes the stator winding  51  and a stator core  52 . The stator winding  51  is formed so as to be wound into an approximately cylindrical shape (annular shape). The stator core  52  is arranged on the radially inner side of the stator winding  51  and serves as a base member. The stator winding  51  is arranged so as to oppose the circular annular magnet unit  42  with a predetermined airgap therebetween. The stator winding  51  is made of a plurality of phase windings. Each of the phase windings is configured by a plurality of conductors that are arrayed in the circumferential direction being connected to one other at a predetermined pitch. 
     According to the present embodiment, a three-phase winding of a U-phase, a V-phase, and a W-phase and a three-phase winding of an X-phase, a Y-phase, and a Z-phase are used. Through use of two of these three-phase windings, the stator winding  51  is configured as a phase winding of six phases. 
     The stator core  52  has laminated steel sheets in which electromagnetic steel sheets are formed into a laminated circular annular shape. The electromagnetic steel sheet is a soft magnetic material. The stator core  52  is assembled on the radially inner side of the stator winding  51 . For example, the electromagnetic steel sheet is a silicon steel sheet in which about several % (such as 3%) silicon is added to iron. The stator winding  51  corresponds to an armature winding. The stator core  52  corresponds to an armature core. 
     The stator winding  51  includes a coil side portion  53  and coil ends  54  and  55 . The coil side portion  53  is a portion that overlaps the stator core  52  in the radial direction and is on the radially outer side of the stator core  52 . The coil ends  54  and  55  respectively protrude from one end side and another end side of the stator core  52  in the axial direction. 
     The coil side portion  53  opposes each of the stator core  52  and the magnet unit  42  of the rotor  40  in the radial direction. In a state in which the stator  50  is arranged on the inner side of the rotor  40 , of the coil ends  54  and  55  on both sides in the axial direction, the coil end  54  that is on the side of the bearing unit  20  (upper side in the drawing) is housed in the coil-housing recessing portion  47  that is formed by the magnet holder  41  of the rotor  40 . However, details of the stator  50  will be described hereafter. 
     The inverter unit  60  includes a unit base  61  and a plurality of electrical components  62 . The unit base  61  is fixed to the housing  30  by a fastener such as a bolt. The plurality of electrical components  62  are assembled to the unit base  61 . For example, the unit base  61  is made of a CFRP. The unit base  61  includes an end plate  63  and a casing  64 . The end plate  63  is fixed to an edge of the opening  33  of the housing  30 . The casing  64  is provided integrally with the end plate  63  and extends in the axial direction. The end plate  63  has a circular opening  65  in a center portion thereof. The casing  64  is formed so as to stand erect (protrude) from a circumferential edge portion of the opening  65 . 
     The stator  50  is assembled to an outer circumferential surface of the casing  64 . That is, an outer diameter dimension of the casing  64  is a dimension that is same as an inner diameter dimension of the stator core  52  or slightly smaller than the inner diameter dimension of the stator core  52 . As a result of the stator core  52  being assembled on the outer side of the casing  64 , the stator  50  and the unit base  61  are integrated. In addition, because the unit base  61  is fixed to the housing  30 , in the state in which the stator core  52  is assembled to the casing  64 , the stator  50  is in a state of being integrated with the housing  30 . 
     Here, the stator core  52  may be assembled to the unit base  61  by bonding, shrink-fitting, press-fitting, or the like. As a result, positional shifting of the stator core  52  in the circumferential direction or the axial direction in relation to the unit base  61  side is suppressed. 
     In addition, a radially inner side of the casing  64  is a housing space for housing the electrical components  62 . The electrical components  62  are arranged in the housing space so as to surround the rotation shaft  11 . The casing  64  serves a role as a housing-space forming portion. The electrical components  62  are configured to actualize a semiconductor module  66  that configures an inverter circuit, a control board  67 , and a capacitor module  68 . 
     Here, the unit base  61  is provided on the radially inner side of the stator  50  and corresponds to a stator holder (armature holder) that holds the stator  50 . The housing  30  and the unit base  61  configure a motor housing of the rotating electric machine  10 . In the motor housing, the holding member  23  is fixed to the housing  30  on one side in the axial direction with the rotor  40  therebetween, and the housing  30  and the unit base  61  are coupled with each other on the other side. For example, in an electric vehicle that is an electric automobile or the like, the rotating electric machine  10  is mounted in the vehicle or the like by the motor housing being attached on the side of the vehicle or the like. 
     Here, the configuration of the inverter unit  60  will be further described with reference to  FIG. 6 , in addition to above-described  FIG. 1  to  FIG. 5 .  FIG. 6  is an exploded view of the inverter unit  60 . 
     In the unit base  61 , the casing  64  includes a cylindrical portion  71  and an end surface  72  that is provided on one (an end portion on the bearing unit  20  side) of both ends that are opposing in the axial direction of the cylindrical portion  71 . A side opposite the end surface  72  of both end portions in the axial direction of the cylindrical portion  71  is completely open through the opening  65  of the end plate  63 . 
     A circular hole  73  is formed in a center of the end surface  72 . The rotation shaft  11  can be inserted into the hole  73 . A sealing member  171  that seals a gap between the end surface  72  and the outer circumferential surface of the rotation shaft  11  is provided in the hole  73 . For example, the sealing member  171  may be a sliding seal that is made of a resin material. 
     The cylindrical portion  71  of the casing  64  is a partitioning portion that partitions between the rotor  40  and the stator  50  that are arranged on a radially outer side thereof, and the electrical components  62  that are arranged on a radially inner side thereof. The rotor  40  and the stator  50 , and the electrical components  62  are respectively arranged so as to be arrayed on the inner side and the radially outer side with the cylindrical portion  71  therebetween. 
     In addition, the electrical component  62  is an electrical component that configures an inverter circuit. The electrical component  62  provides a power-running function for supplying a current to the phase windings of the stator winding  51  in a predetermined order and rotating the rotor  40 , and a power generation function for receiving input of a three-phase alternating-current current that flows through the stator winding  51  in accompaniment with the rotation of the rotation shaft  11  and outputting the three-phase alternating-current current outside as generated power. 
     Here, the electrical component  62  may only provide either of the power-running function and the power generation function. For example, when the rotating electric machine  10  is used as a vehicle power source, the power generation function is a regeneration function for outputting the three-phase alternating-current current outside as regenerative power. 
     As shown in  FIG. 4 , as a specific configuration of the electrical components  62 , a capacitor module  68  that has a hollow circular cylindrical shape is provided around the rotation shaft  11 , and a plurality of semiconductor modules  66  are arranged in an array in the circumferential direction on an outer circumferential surface of the capacitor module  68 . The capacitor module  68  includes a plurality of smoothing capacitors  68   a  that are connected to one another in parallel. 
     Specifically, the capacitor  68   a  is a laminated-type film capacitor that is made of a plurality of film capacitors being laminated. A lateral cross-section of the capacitor  68   a  has a trapezoidal shape. The capacitor module  68  is configured by twelve capacitors  68   a  being arranged so as to be annularly arrayed. 
     Here, for example, in a manufacturing process for the capacitor  68   a , a capacitor element is fabricated using an elongated film that has a predetermined width and is made of a plurality of films being laminated. The elongated film is cut into isosceles trapezoids such that a film-width direction serves as a trapezoid-height direction, and tops and bottoms of the trapezoids alternate. In addition, the capacitor  68   a  is fabricated by electrodes and the like being attached to the capacitor element. 
     For example, the semiconductor module  66  has a semiconductor switching element, such as a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT), and is formed into an approximately plate-like shape. 
     According to the present embodiment, the rotating electric machine  10  includes two sets of three-phase windings. The inverter circuit is provided for each of the three-phase windings. Therefore, a semiconductor module group  66 A that is formed by a total of twelve semiconductor modules  66  being annularly arrayed is provided in the electrical components  62 . 
     The semiconductor module  66  is arranged so as to be sandwiched between the cylindrical portion  71  of the casing  64  and the capacitor module  68 . An outer circumferential surface of the semiconductor module group  66 A is in contact with an inner circumferential surface of the cylindrical portion  71 . An inner circumferential surface of the semiconductor module group  66 A is in contact with the outer circumferential surface of the capacitor module  68 . In this case, heat that is generated in the semiconductor module  66  is transmitted to the end plate  63  through the casing  64  and released from the end plate  63 . 
     The semiconductor module group  66 A may include a spacer  69  on the outer circumferential surface side, that is, between the semiconductor modules  66  and the cylindrical portion  71  in the radial direction. In this case, in the capacitor module  68 , a cross-sectional shape of a lateral cross-section that is orthogonal to the axial direction is a regular dodecagon. Meanwhile, a lateral cross-sectional shape of the inner circumferential surface of the cylindrical portion  71  is a circular shape. 
     Therefore, in the spacer  69 , an inner circumferential surface is a flat surface and an outer circumferential surface is a curved surface. The spacer  69  may be integrally provided on the radially outer side of the semiconductor module group  66 A so as to be continuous in a circular annular shape. The spacer  69  is a good heat conductor and, for example, may be made of a metal such as aluminum or a heat-radiation gel sheet. Here, the lateral cross-sectional shape of the inner circumferential surface of the cylindrical portion  71  can also be a dodecagon that is identical to the capacitor module  68 . In this case, both the inner circumferential surface and the outer circumferential surface of the spacer  69  may be flat surfaces. 
     In addition, according to the present embodiment, a cooling water passage  74  through which cooling water flows is formed in the cylindrical portion  71  of the casing  64 . Heat that is generated in the semiconductor modules  66  is released to the cooling water that flows through the cooling water passage  74  as well. That is, the casing  64  includes a water-cooled mechanism. 
     As shown in  FIG. 3  and  FIG. 4 , the cooling water passage  74  is formed into an annular shape so as to surround the electrical components  62  (the semiconductor modules  66  and the capacitor module  68 ). The semiconductor modules  66  are arranged along the inner circumferential surface of the cylindrical portion  71 . The cooling water passage  74  is provided in a position that overlaps the semiconductor modules  66  on the inner side and the radially outer side. 
     The stator  50  is arranged on the outer side of the cylindrical portion  71  and the electrical components  62  are arranged on the inner side. Therefore, heat from the stator  50  is transmitted to the cylindrical portion  71  from the outer side thereof, and heat from the electrical components  62  (such as heat from the semiconductor modules  66 ) is transmitted from the inner side. In this case, the stator  50  and the semiconductor modules  66  can be simultaneously cooled. Heat from heat generating components of the rotating electric machine  10  can be efficiently released. 
     Furthermore, at least a portion of the semiconductor modules  66  that configure a portion or an entirety of the inverter circuit that operates the rotating electric machine by performing energization of the stator winding  51  is arranged inside an area that is surrounded by the stator core  52  that is arranged on the radially outer side of the cylindrical portion  71  of the casing  64 . The entirety of a single semiconductor module  66  is preferably arranged inside the area that is surrounded by the stator core  52 . Furthermore, the entirety of all semiconductor modules  66  is preferably arranged inside the area that is surrounded by the stator core  52 . 
     In addition, at least a portion of the semiconductor modules  66  is arranged inside an area that is surrounded by the cooling water passage  74 . The entirety of all of the semiconductor modules  66  is preferably arranged inside an area that is surrounded by a yoke  141 . 
     Moreover, the electrical components  62  include, in the axial direction, an insulating sheet  75  that is provided on one end surface of the capacitor module  68  and a wiring module  76  that is provided on another end surface. In this case, the capacitor module  68  includes two end surfaces that are opposing in the axial direction thereof, that is, a first end surface and a second end surface. The first end surface of the capacitor module  68  that is close to the bearing unit  20  opposes the end surface  72  of the casing  64  and overlaps the end surface  72  with the insulating sheet  75  sandwiched therebetween. In addition, the wiring module  76  is assembled to the second end surface of the capacitor module  68  that is close to the opening  65 . 
     The wiring module  76  includes a main body portion  76   a  and a plurality of bus bars  76   b  and  76   c . The main body portion  76   a  is made of a synthetic resin material and has a circular plate shape. The plurality of bus bars  76   b  and  76   c  are embedded inside the main body portion  76   a . Electrical connection with the semiconductor modules  66  and the capacitor module  68  is achieved by the bus bars  76   b  and  76   c.    
     Specifically, the semiconductor module  66  includes a connection pin  66   a  that extends from an end surface in the axial direction thereof. The connection pin  66   a  is connected to the bus bar  76   b  on a radially outer side of the main body portion  76   a . In addition, the bus bar  76   c  extends towards a side opposite the capacitor module  68  on the radially outer side of the main body portion  76   a . The bus bar  76   c  is connected to a wiring member  79  at a tip end portion thereof (see  FIG. 2 ). 
     As described above, the insulating sheet  75  is provided on the first end surface that is opposing in the axial direction of the capacitor module  68 , and the wiring module  76  is provided on the second surface of the capacitor module  68 . In this configuration, as a heat releasing path of the capacitor module  68 , a path from the first end surface and the second end surface of the capacitor module  68  to the end surface  72  and the cylindrical portion  71  is formed. 
     That is, a path from the first end surface to the end surface  72  and a path from the second end surface to the cylindrical portion  71  are formed. As a result, heat release from the end surface portions of the capacitor module  68  other than the outer circumferential surface on which the semiconductor modules  66  are provided can be performed. That is, heat release can be performed not only in the radial direction but also the axial direction. 
     In addition, the capacitor module  68  has a hollow circular cylindrical shape. The rotation shaft  11  is arranged in an inner circumferential portion thereof with a predetermined gap interposed therebetween. Therefore, heat from the capacitor module  68  can also be released from the hollow portion thereof. In this case, as a result of a flow of air being generated by the rotation of the rotation shaft  11 , the cooling effect thereof can be improved. 
     The circular plate-shaped control board  67  is attached to the wiring module  76 . The control board  67  includes a printed circuit board (PCB) on which a predetermined wiring pattern is formed. A control apparatus  77  that corresponds to a control unit that is made of various types of integrated circuits (IC), microcomputers, and the like is mounted on the board. The control board  67  is fixed to the wiring module  76  by a fixture such as a screw. The control board  67  has an insertion hole  67   a  through which the rotational shaft  11  is inserted in a center portion thereof. 
     Here, the wiring module  76  has a first surface and a second surface that oppose each other in the axial direction, that is, oppose each other in a thickness direction thereof. The first surface faces the capacitor module  68 . The wiring module  76  is provided with the control board  67  on the second surface thereof. The bus bar  76   c  of the wiring module  76  extends from one side to the other side of both surfaces of the control board  67 . In this configuration, the control board  67  may be provided with a notch that prevents interference with the bus bar  76   c . For example, a portion of an outer edge portion of the control board  67  that has the circular shape may be notched. 
     As described above, the electrical components  62  are housed inside the space that is surrounded by the casing  64 , and the housing  30 , the rotor  40 , and the stator  50  are provided in layers on the outer side thereof. In this configuration, shielding from electromagnetic noise that is generated in the inverter circuit is suitably performed. 
     That is, in the inverter circuit, switching control being performed in each of the semiconductor modules  66  using pulse width modulation (PWM) control based on a predetermined carrier frequency and electromagnetic noise being generated as a result of the switching control can be considered. However, shielding from this electromagnetic noise can be suitably performed by the housing  30 , the rotor  40 , the stator  50 , and the like on the outer side of in the radial direction the electrical components  62 . 
     Furthermore, as a result of at least a portion of the semiconductor modules  66  being arranged inside the area that is surrounded by the stator core  52  that is arranged on the radially outer side of the cylindrical portion  71  of the casing  64 , compared to a configuration in which the semiconductor modules  66  and the stator winding  51  are arranged without the stator core  52  therebetween, even if magnetic flux is generated from the semiconductor modules  66 , the stator winding  51  is not easily affected. 
     In addition, even if magnetic flux is generated from the stator winding  51 , the semiconductor modules  66  are not easily affected. Here, it is even more effective to arrange the overall semiconductor modules  66  inside the area that is surrounded by the stator core  52  that is arranged on the radially outer side of the cylindrical portion  71  of the casing  64 . In addition, when at least a portion of the semiconductor modules  66  is surrounded by the cooling water passage  74 , an effect in which heat generated from the stator winding  51  and the magnet unit  42  does not easily reach the semiconductor modules  66  can be achieved. 
     A through hole  78  through which the wiring member  79  (see  FIG. 2 ) is inserted is formed near the end plate  63  in the cylindrical portion  71 . The wiring member  79  electrically connects the stator  50  on the outer side of the cylindrical portion  71  and the electrical components  62  on the inner side thereof. 
     As shown in  FIG. 2 , the wiring member  79  is connected to each of the end portion of the stator winding  51  and the bus bar  76   c  of the wiring module  76  by press-fitting, welding, or the like. For example, the wiring member  79  is a bus bar. A joining surface of the wiring member  79  is preferably crushed to be flat. The through hole  78  may be provided in a single location or a plurality of locations. 
     According to the present embodiment, the through holes  78  are provided in two locations. In this configuration, winding terminals that extend from the two sets of three-phase windings can each easily be connected by the wiring member  79 . This is suitable in terms of performing multi-phase connection. 
     As described above, as shown in  FIG. 4 , inside the housing  30 , the rotor  40  and the stator  50  are provided in order from the radially outer side, and the inverter unit  60  is provided on the radially inner side of the stator  50 . Here, when a radius of the inner circumferential surface of the housing  30  is d, the rotor  40  and the stator  50  are arranged further towards the radially outer side than a distance of d x  0 . 705  from a rotational center of the rotor  40  is. 
     In this case, when an area on the radially inner side from an inner circumferential surface of the stator  50  (that is, an inner circumferential surface of the stator core  52 ) that is on the radially inner side, of the rotor  40  and the stator  50 , is a first area X 1  and an area from the inner circumferential surface of the stator  50  to the housing  30  in the radial direction is a second area X 2 , an area of a lateral cross-section of the first area X 1  is greater than an area of a lateral cross-section of the second area X 2 . 
     In addition, in terms of an area over which which the magnet unit  42  of the rotor  40  and stator winding  51  overlap in the radial direction, a volume of the first area X 1  is greater than a volume of the second area X 2   
     Here, if the rotor  40  and the stator  50  are considered a magnetic circuit component assembly, inside the housing  30 , the first area X 1  that is on the radially inner side from an inner circumferential surface of the magnetic circuit component assembly has a greater volume than the second area X 2  that is from the inner circumferential surface of the magnetic circuit component assembly to the housing  30  in the radial direction. 
     Next, the configurations of the rotor  40  and the stator  50  will be described in further detail. 
     As a configuration of a stator in a rotating electric machine, a configuration in which a plurality of slots are provided in the circumferential direction in a stator core that is made of laminated steel sheets and has a circular annular shape, and a stator winding is wound through the slots is generally known. Specifically, the stator core includes a plurality of teeth that extend in the radial direction from a yoke at predetermined intervals. The slots are formed between the teeth that are adjacent to each other in the circumferential direction. In addition, for example, a plurality of layers of conductors are housed inside the slots in the radial direction, and the stator winding is configured by these conductors. 
     However, in the above-described stator structure, during energization of the stator winding, magnetic saturation occurring in the teeth portion of the stator core in accompaniment with increase in magnetomotive force in the stator winding, and torque density of the rotating electric machine becoming limited as a result thereof can be considered. That is, in the stator core, magnetic saturation occurs as a result of a rotating magnetic flux that is generated by the energization of the stator winding being concentrated at the teeth. 
     In addition, as a configuration of an interior permanent magnet (IPM) rotor of a rotating electric machine, a configuration in which a permanent magnet is arranged on a d-axis and a rotor core is arranged on a q-axis of a d-q coordinate system is generally known. In such cases, as a result of the stator winding near the d-axis being excited, an excitation magnetic flux flows from the stator to the q-axis of the rotor as a result of Fleming&#39;s Rule. In addition, as a result, magnetic saturation over a wide area is thought to occur in a q-axis core portion of the rotor. 
       FIG. 7  is a torque diagram of a relationship between ampere-turns [AT] and torque density [Nm/L]. The ampere-turns indicates magnetomotive force in the stator winding. A broken line indicates characteristics of a typical IPM-rotor-type rotating electric machine. As shown in  FIG. 7 , in the typical rotating electric machine, as a result of the magnetomotive force being increased in the stator, magnetic saturation occurs in two locations that are the teeth portion between the slots and the q-axis core portion, and increase in torque becomes limited as a result. In this manner, in the typical rotating electric machine, an ampere-turns design value is limited by A 1 . 
     Here, according to the present embodiment, to eliminate limitations attributed to magnetic saturation, the rotating electric machine  10  is also provided with a configuration described below. That is, as a first modification, a slot-less structure is used in the stator  50  to eliminate magnetic saturation that occurs in the teeth of the stator core in the stator. In addition, a surface permanent magnet (SPM) rotor is used to eliminate magnetic saturation that occurs in the q-axis core portion of the IPM rotor. 
     As a result of the first modification, the above-described two locations in which magnetic saturation occurs can be eliminated. However, decrease in torque in a low-current region can be considered (refer to a single-dot chain line in  FIG. 7 ). Therefore, as a second modification, a polar anisotropic structure in which a magnet magnetic path is extended and magnetic force is increased in the magnet unit  42  of the rotor  40  is used to recover the decrease in torque through magnetic flux enhancement in the SPM rotor. 
     In addition, as a third modification, recovery of the decrease in torque is achieved through use of a flattened conductor structure in which a thickness of the conductor in the radial direction of the stator  50  is reduced in the coil side portion  53  of the stator winding  51 . Here, larger eddy currents are thought to be generated in the stator winding  51  that opposes the magnet unit  42 , as a result of the above-described polar anisotropic structure in which the magnetic force is increased. 
     However, as a result of the third modification, the generation of eddy currents in the radial direction in the stator winding  51  can be suppressed because of the flattened conductor structure that is thin in the radial direction. In this manner, as a result of these first to third configurations, even while significant improvement in torque characteristics can be expected through use of a magnet that has high magnetic force, as indicated by a solid line in  FIG. 7 , concern regarding the generation of large eddy currents that may occur as a result of the magnet that has high magnetic force can be ameliorated as well. 
     Furthermore, as a fourth modification, a magnet unit that has a magnetic flux density distribution that is close to a sine wave is used through use of the polar anisotropic structure. As a result, a sine-wave matching ratio can be improved by pulse control, described hereafter, or the like and torque enhancement can be achieved. In addition, because changes in magnetic flux are more gradual compared to that of a radial magnet, eddy current loss (copper loss due to eddy currents) can also be further suppressed. 
     The sine-wave matching ratio will be described below. The sine-wave matching ratio can be determined based on a comparison between an actual measured waveform of a surface magnetic flux density distribution that is measured by a surface of a magnet being traced by a magnetic flux probe or the like, and a sine wave that has a same period and a same peak value. In addition, a proportion of an amplitude of a primary waveform that is a fundamental wave of the rotating electric machine in relation to an amplitude of the actual measured waveform, that is, an amplitude obtained by another harmonic component being added to the fundamental wave corresponds to the sine-wave matching ratio. 
     As the sine-wave matching ratio increases, the waveform of the surface magnetic flux density distribution becomes closer to the sine-wave waveform. In addition, when a primary sine-wave current is supplied from an inverter to the rotating electric machine that includes a magnet that has an improved sine-wave matching ratio, because of this and the waveform of the surface magnetic flux density distribution of the magnet being close to the sine waveform as well, a large torque can be generated. Here, the surface magnetic flux density distribution may be estimated by a method other than actual measurement, such as by an electromagnetic field analysis using Maxwell&#39;s equations. 
     In addition, as a fifth modification, the stator winding  51  has a wire conductor body structure in which a plurality of wires are gathered together and bundled. As a result, because the wires are connected in parallel, a large current can be supplied. In addition, the generation of eddy currents that are generated in the conductors that are spread in the circumferential direction of the stator  50  as a result of the flattened conductor structure can be suppressed more effectively than when the conductors are made thinner in the radial direction as a result of the third modification, because a cross-sectional area of each wire is reduced. In addition, as a result of a configuration in which the plurality of wires are twisted together, regarding magnetomotive force from a conductor body, eddy currents from a magnetic flux that is generated based on a right-hand screw rule in a current conduction direction can be cancelled. 
     In this manner, as a result of the fourth modification and the fifth modification being further added, torque enhancement can be achieved while a magnet that has a high magnetic force that is the second modification is used and, further, while the eddy current loss attributed to the high magnetic force is suppressed. 
     Descriptions of the above-described slot-less structure of the stator  50 , flattened conductor structure of the stator winding  51 , and polar anisotropic structure of the magnet unit  42  are separately added below. Here, first, the slot-less structure of the stator  50  and the flattened conductor structure of the stator winding  51  will be described. 
       FIG. 8  is a lateral cross-sectional view of the rotor  40  and the stator  50 .  FIG. 9  is a diagram showing a portion of the rotor  40  and the stator  50  shown in  FIG. 8  in an enlarged manner.  FIG. 10  is a cross-sectional view showing a lateral cross-section of the stator  50  taken along line X-X in  FIG. 11 .  FIG. 11  is a cross-sectional view showing a vertical cross-section of the stator  50 . In addition,  FIG. 12  is a perspective view of the stator winding  51 . Here, in  FIG. 8  and  FIG. 9 , a magnetization direction of the magnets in the magnet unit  42  is indicated by an arrow. 
     As shown in  FIG. 8  to  FIG. 11 , the stator core  52  is that in which a plurality of electromagnetic steel sheets are laminated in the axial direction. The stator core  52  has a circular cylindrical shape that has a predetermined thickness in the radial direction. The stator winding  51  is assembled on the radially outer side of the stator core  52  that is the rotor  42  side. In the stator core  52 , the outer circumferential surface on the rotor  40  side serves as a conductor setup portion (conductor body area). The outer circumferential surface of the stator core  52  has a curved surface shape that has no unevenness. 
     A plurality of conductor groups  81  are arranged on the outer circumferential surface of the stator core  52  at predetermined intervals in the circumferential direction. The stator core  52  functions as a back yoke that serves as a portion of a magnetic circuit for rotating the rotor  40 . In this case, a tooth (that is, a core) that is made of a soft magnetic material is not provided between two conductor groups  81  that are adjacent to each other in the circumferential direction (that is, a slot-less structure). 
     According to the present embodiment, the structure is such that a resin material of a sealing member  57  enters a gap  56  between the conductor groups  81 . That is, in the stator  50 , a conductor-to-conductor member that is provided between the conductor groups  81  in the circumferential direction is configured as the sealing member  57  that is a non-magnetic material. In terms of a state before sealing by the sealing member  57 , the conductor groups  81  are arranged on the radially outer side of the stator core  52 , at predetermined intervals in the circumferential direction so as to each be separated by the gap  56  that is a conductor-to-conductor area. 
     The stator  50  that has a slot-less structure is thereby constructed. In other words, each conductor group  81  is made of two conductors  82 , as described hereafter. Only a non-magnetic material occupies the area between two conductor groups  81  that are adjacent to each other in the circumferential direction of the stator  50 . The non-magnetic material includes a non-magnetic gas such as air, a non-magnetic liquid, and the like, in addition to the sealing member  57 . Hereafter, the sealing member  57  is also referred to as the conductor-to-conductor member. 
     Here, the configuration in which the teeth are provided between the conductor groups  81  that are arrayed in the circumferential direction can be said to be a configuration in which, as a result of the teeth having a predetermined thickness in the radial direction and a predetermined width in the circumferential direction, a portion of the magnetic circuit, that is, a magnet magnetic path is formed between the conductor groups  81 . In this regard, the configuration in which the teeth are not provided between the conductor groups  81  can be said to be a configuration in which the above-described magnetic circuit is not formed. 
     As shown in  FIG. 10 , the stator winding (that is, the armature winding)  51  is formed to have a predetermined thickness T 2  (also referred to, hereafter, as a first dimension) and width W 2  (also referred to, hereafter, as a second dimension). The thickness T 2  is a shortest distance between the outer circumferential surface and the inner circumferential surface that oppose each other in the radial direction of the stator winding  51 . The width W 2  is a length, in the circumferential direction of the stator winding  51 , of a portion of the stator winding  51  that functions as one of the multiple phases (in the example, three phases: three phases that are the U-phase, V-phase, and W-phase or three phases that are the X-phase, Y-phase, and Z-phase) of the stator winding  51 . 
     Specifically, in  FIG. 10 , when the two conductor groups  81  that are adjacent to each other in the circumferential direction function as one of the three phases, such as the U-phase, the width W 2  is from end to end of the two conductor groups  81  in the circumferential direction. In addition, the thickness T 2  is less than the width W 2 . 
     Here, the thickness T 2  is preferably less than a total width dimension of the two conductor groups  81  that are present within the width W 2 . In addition, if the cross-sectional shape of the stator winding  51  (more specifically, the conductors  82 ) is perfectly circular, elliptical, or polygonal, of the cross-section of the conductors  82  along the radial direction of the stator  50 , a maximum length in the radial direction of the stator  50  on the cross-section may be W 12  and a maximum length in the circumferential direction of the stator  50  on the same cross-section may be W 11 . 
     As shown in  FIG. 10  and  FIG. 11 , the stator winding  51  is sealed by the sealing member  57  that is made of a synthetic resin material that serves as a sealing material (molding material). That is, the stator winding  51  is molded by the molding material, together with the stator core  52 . Here, the resin may be a non-magnetic body or an equivalent of a non-magnetic body in which Bs = 0 . 
     In terms of the lateral cross-section in  FIG. 10 , the sealing member  57  is provided by the synthetic resin filling the area between the conductor groups  81 , that is, the gaps  56 . An insulation member is interposed between the conductor groups  81  as a result of the sealing member  57 . That is, the sealing member  57  functions as an insulation member in the gap  56 . The sealing member  57  is provided on the radially outer side of the stator core  52 , over an area that includes all of the conductor groups  81 , that is, over an area in which a thickness dimension in the radial direction is greater than the thickness dimension in the radial direction of each conductor group  81 . 
     In addition, in terms of the vertical cross-section in  FIG. 11 , the sealing member  57  is provided over an area that includes a turn portion  84  of the stator winding  51 . The sealing member  57  is provided on the radially inner side of the stator winding  51 , over an area that includes at least a portion of an end surface of the stator core  52  that is opposing in the axial direction. In this case, the stator winding  51  is approximately entirely sealed by resin, excluding the end portion of the phase winding of each phase, that is, the connection terminals for the inverter circuit. 
     The sealing member  57  is provided over an area that includes the end surface of the stator core  52 . In this configuration, the laminated steel sheets of the stator core  52  can be pressed towards the inner side in the axial direction by the sealing member  57 . As a result, the state of lamination of the steel sheets can be maintained using the sealing member  57 . Here, according to the present embodiment, the inner circumferential surface of the stator core  52  is not sealed by resin. However, instead, the overall stator core  52  including the inner circumferential surface of the stator core  52  may be sealed by resin. 
     When the rotating electric machine  10  is used as a vehicle power source, the sealing member  57  is preferably made of fluorine resin that has high heat resistance, epoxy resin, polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, liquid crystal polymer (LCP) resin, silicone resin, polyamide-imide (PAI) resin, polyimide (PI) resin, or the like. 
     In addition, when a coefficient of linear expansion is considered from a perspective of suppressing cracks caused by differences in expansion, the sealing member  57  is preferably made of a material that is same as that of an outer coating of the conductors of the stator winding  51 . That is, the silicone resin of which the coefficient of linear expansion is generally equal to or greater than twice that of other resins is preferably excluded. 
     Here, in electrical products that do not have an engine that uses combustion like the electric vehicle, poly(p-phenylene oxide) (PPO) resin and phenolic resin that have heat resistance of about 180° C., and fiber-reinforced plastic (FRP) resin are also candidates. In fields in which ambient temperature of the rotating electric machine can be assumed to be less than 100° C., the materials are not limited to the foregoing. 
     The torque of the rotating electric machine  10  is proportional to the magnitude of the magnetic flux. Here, when the stator core has teeth, a maximum magnetic flux amount of the stator is dependent on and limited by the saturation magnetic flux density at the teeth. However, when the stator core does not have teeth, the maximum magnetic flux amount of the stator is not limited. Therefore, the configuration is advantageous in terms of increasing a conduction current to the stator winding  51  and achieving torque increase in the rotating electric machine  10 . 
     According to the present embodiment, inductance in the stator  50  decreases as a result of the structure (slot-less structure) in which the teeth are eliminated being used in the stator  50 . Specifically, whereas the inductance in a stator of a typical rotating electric machine in which conductors are housed in slots that are partitioned by a plurality of teeth is, for example, about 1 mH, the inductance is reduced to about 5 pH to 60 pH in the stator  50  according to the present embodiment. 
     According to the present embodiment, even with the rotating electric machine  10  that has the outer-rotor structure, a mechanical time constant Tm can be reduced through reduction of the inductance in the stator  50 . That is, reduction of the mechanical time constant Tm can be achieved while higher torque is achieved. Here, when inertia is J, inductance is L, a torque constant is Kt, and a counter electromotive force constant is Ke, the mechanical time constant Tm is calculated by a following expression. 
         Tm =( J×L )/( Kt×Ke ) 
     In this case, it can be confirmed that the mechanical time constant Tm decreases as a result of decrease in the inductance L. 
     The conductor groups  81  on the radially outer side of the stator core  52  are configured such that a plurality of conductors  82  of which a cross-section forms a flattened rectangular shape are arranged so as to be arrayed in the radial direction of the stator core  52 . The conductor  82  is arranged to be oriented such that, on a lateral cross-section, radial direction dimension &lt;circumferential direction dimension. 
     As a result, thinness in the radial direction is achieved in each conductor group  81 . Furthermore, in addition to thinness in the radial direction being achieved, a conductor-body area extends in a planar manner to an area in which teeth were originally provided, and a flattened conductor area structure is formed. As a result, increase in a heat generation quantity of the conductors that becomes a concern as a result of the cross-sectional area becoming smaller as a result of being thinner is suppressed by the cross-sectional area of the conductor body being increased through flattening in the circumferential direction. Here, even when the plurality of conductors are arrayed in the circumferential direction and connected in parallel, although decrease in a conductor-body cross-sectional area that amounts to the conductor coating occurs, effects based on the same reasoning can be achieved. Here, each of the conductor groups  81  and each of the conductors  82  may also be referred to as a conductive member, below. 
     Because slots are not provided, in the stator winding  51  according to the present embodiment, the conductor-body area that is occupied by the stator winding  51  in a single round in the circumferential direction can be designed to be greater than a conductor-body unoccupied area in which the stator winding  51  is not present. 
     Here, in a conventional rotating electric machine for a vehicle, the conductor-body area/conductor-body unoccupied area in a single round in the circumferential direction of the stator winding being equal to or less than  1  is a matter of course. Meanwhile, according to the present embodiment, the conductor groups  81  are provided such that the conductor-body area is equal to the conductor-body unoccupied area or the conductor-body area is greater than the conductor-body unoccupied area. 
     Here, as shown in  FIG. 10 , when a conductor area in which the conductors  82  (that is, a linear portions  83 , described hereafter) is arranged in the circumferential direction is a WA and an inter-conductor area between adjacent conductors  82  is WB, the conductor area WA is greater in the circumferential direction than the conductor area WB. 
     As the conductor group  81  in the stator winding  51 , a thickness dimension in the radial direction of the conductor group  81  is less than a width dimension in the circumferential direction amounting to a single phase within a single magnetic pole. That is, the conductor group  81  is made of two layers of conductors  82  in the radial direction, and two conductor groups  81  are provided in the circumferential direction for a single phase within a single magnetic pole. In this configuration, a relationship expressed by Tc×2&lt;Wv×2 is established, where Tc is the thickness dimension in the radial direction of the conductor  82 , and We is the width dimension in the circumferential direction of the conductor  82 . 
     Here, as another configuration, the conductor group  81  may be made of two layers of conductors  82 , and a single conductor group  81  may be provided in the circumferential direction for a single phase within a single magnetic pole. In this configuration, a relationship expressed by Tc×2&lt;Wc may be established. In short, the conductor portions (conductor groups  81 ) that are arranged at predetermined intervals in the circumferential direction in the stator winding  51  are that in which the thickness dimension in the radial direction thereof is less than the width dimension in the circumferential direction amounting to a single phase within a single magnetic pole. 
     In other words, each of the conductors  82  may be such that the thickness dimension Tc in the radial direction is less than the width dimension Wc in the circumferential direction. In addition, further, the thickness dimension ( 2 Tc) in the radial direction of the conductor group  81  that is made of two layers of the conductors  82  in the radial direction, that is, the thickness dimension ( 2 Tc) in the radial direction of the conductor group  81  may be less than the width dimension Wc in the circumferential direction. 
     The torque of the rotating electric machine  10  is approximately inversely proportional to the thickness in the radial direction of the stator core  52  of the conductor group  81 . In this regard, as a result of the thickness of the conductor group  81  being made thinner on the radially outer side of the stator core  52 , the configuration is advantageous in terms of achieving torque increase in the rotating electric machine  10 . A reason for this is that a distance from the magnet unit  42  of the rotor  40  to the stator core  52  (that is, a distance of a portion that includes no iron) can be reduced and magnetic resistance can be reduced. As a result, interlinkage flux in the stator core  52  by the permanent magnet can be increased and torque can be enhanced. 
     In addition, as a result of the thickness of the conductor group  81  being made thinner, even when magnetic flux leaks from the conductor group  81 , the magnetic flux can be easily recovered in the stator core  52 . The magnetic flux leaking outside and not being effectively used for torque improvement can be suppressed. That is, reduction in magnetic force as a result of magnetic flux leakage can be suppressed. The interlinkage flux in the stator core  52  by the permanent magnet can be increased, and torque can be enhanced. 
     The conductor  82  is made of a coated conductor in which a surface of a conductor body  82   a  is covered by an insulation coating  82   b . Insulation is ensured between the conductors  82  that overlap each other in the radial direction and between the conductor  82  and the stator core  52 . When the wire  86 , described hereafter, is a self-fusing coated wire, the insulation coating  82   b  is made of the coating of the wire  86 . Alternatively, the insulation coating  82   b  is made of an insulation member that is overlayed separately from the coating of the wire  86 . 
     Here, in each of the phase windings that are configured by the conductors  82 , insulation properties of the insulation coating  82   b  are maintained, excluding an exposed portion for connection. For example, the exposed portion is an input/output terminal portion or a neutral point portion when a star connection is formed. In the conductor group  81 , the conductors  82  that are adjacent in the radial direction are mutually fixed using resin fixing or self-fusing coated wires. As a result, insulation breakdown, vibrations, and noise that occur as a result of the conductors  82  rubbing together are suppressed. 
     According to the present embodiment, the conductor body  82   a  is configured as a bundle of a plurality of wires  86 . Specifically, as shown in  FIG. 13 , the conductor body  82   a  is formed into a shape of twisted yarn by the plurality of wires  86  being twisted. In addition, as shown in  FIG. 14 , the wire  86  is configured as a composite in which thin, fibrous conductive materials  87  are bundled. 
     For example, the wire  86  is a composite of carbon nanotube (CNT) fibers. As the CNT fibers, fibers including boron-containing fine fibers in which at least a portion of carbon is replaced with boron is used. As carbon-based fine fibers, in addition to the CNT fibers, vapor-grown carbon fibers (VGCF) and the like can be used. However, the CNT fibers are preferably used. Here, the surface of the wire  86  is covered by a polymer insulation layer such as enamel. In addition, the surface of the wire  86  is preferably covered by a so-called enamel coating that is made of a coating of polyimide or a coating of amide-imide. 
     The conductors  82  configure the windings of n-phases in the stator winding  51 . In addition, the wires  86  of the conductor  82  (that is, the conductor body  82   a ) are adjacent to each other in a state of contact. The conductor  82  is made of a wire bundle in which a winding conductor body has a portion that is formed by the plurality of wires  86  being twisted in one or more locations within a phase, and a resistance value between twisted wires  86  is greater than a resistance value of the wire  86  itself. 
     In other words, when two adjacent wires  86  have a first electrical resistivity in the direction in which the wires  86  are adjacent and each of the wires  86  has a second electrical resistivity in the length direction thereof, the first electrical resistivity is a greater value than the second electrical resistivity. Here, the conductor  82  may be a wire bundle that is formed by the plurality of wires  86 , and in which the plurality of wires  86  are covered by an insulation member that has a very high first electrical resistivity. In addition, the conductor body  82   a  of the conductor  82  is configured by the plurality of wires  86  that are twisted together. 
     In the above-described conductor body  82   a , because the plurality of wires  86  are twisted together, generation of eddy currents in the wires  86  can be suppressed and decrease in eddy currents in the conductor body  82   a  can be achieved. In addition, as a result of the wires  86  being twisted, a section in which directions in which a magnetic field is applied are opposite each other is produced in a single wire  86 , and a counter electromotive voltage is canceled. Therefore, decrease in eddy currents can again be achieved. In addition, as a result of the wire  86  being made of the fibrous conductive materials  87 , thinning and significant increase in the number of twists can be achieved. Eddy currents can be more suitably reduced. 
     Here, an insulation method for the wires  86  herein is not limited to the above-described polymer insulation coating and may be a method in which flow of current is made difficult between the twisted wires  86  using contact resistance. That is, if a relationship is such that the resistance value between the twisted wires  86  is greater than the resistance value of the wire  86  itself, the above-described effects can be achieved as a result of a potential difference that is generated as a result of the difference in resistance values. 
     For example, as a result of a manufacturing facility for fabricating the wire  86  and a manufacturing facility for fabricating the stator  50  (armature) of the rotating electric machine  10  being used as separate discontinuous facilities, the wires  86  can become oxidized due to travel time, work intervals, and the like. Contact resistance can be increased and is, therefore, favorable. 
     As described above, the conductor  82  has a cross-section that has a flattened rectangular shape. A plurality of conductors  82  are arranged so as to be arrayed in the radial direction. For example, the conductor  82  maintains the shape by a plurality of coated wires  86  that are the self-fusing coated wires that include a fusion layer and an insulation layer being bundled in a twisted state and the fusion layers being fused together. 
     Here, the conductor  82  may be formed by wires that do not have the fusion layer or wires that are the self-fusing coated wires being hardened into a desired shape by a synthetic resin or the like in a twisted state. When the thickness of the insulation coating  82   b  of the conductor  82  is, for example, 80 μm to 100 μm and thicker than a coating thickness (5 μm to 40 μm) of a conductor that is typically used, insulation between the conductor  82  and the stator core  52  can be ensured without an insulation paper or the like being interposed therebetween. 
     In addition, the insulation coating  82   b  is preferably configured to have higher insulation properties than the insulation layer of the wire  86  and be capable of insulating between phases. For example, when the thickness of the polymer insulation layer of the wire  86  is about 5 μm, the thickness of the insulation coating  82   b  of the conductor  82  is preferably about 80 μm to 100 μm, and made capable of suitably insulating between phases. 
     Furthermore, the conductor  82  may be configured such that the plurality of wires  86  are bundled without being twisted. That is, the conductor  82  may have any of a configuration in which the plurality of wires  86  are twisted over the overall length thereof, a configuration in which the plurality of wires  86  are twisted in a portion of the overall length, and a configuration in which the plurality of wires  86  are bundled without being twisted over the overall length. In summary, the conductor  82  that configures the conductor portion is a wire bundle in which the plurality of wires  86  are bundled, and the resistance value between the bundled wires is greater than the resistance value of the wire  86  itself. 
     The conductor  82  is formed by bending so as to be arranged in a predetermined arrangement pattern in the circumferential direction of the stator winding  51 . As a result, as the stator winding  51 , a phase winding is formed for each phase. As shown in  FIG. 12 , in the stator winding  51 , the coil side portion  53  is formed by the linear portion  83  of the conductor  82  that linearly extends in the axial direction, and the coil ends  54  and  55  are formed by the turn portions  84  that protrude further towards both outer sides than the coil side portion  53  in the axial direction. 
     As a result of the linear portion  83  and the turn portion  84  being alternately repeated, the conductors  82  are configured as a series of conductors in a wave-winding state. The linear portion  83  is arranged in a position that opposes the magnet unit  42  in the radial direction. The linear portions  83  of the same phase that are arranged with a predetermined interval therebetween in positions on the outer side in the axial direction of the magnet unit  42  are connected to each other by the turn portion  84 . Here, the linear portion  83  corresponds to a “magnet opposing portion.” 
     According to the present embodiment, the stator winding  51  is formed by being wound into a circular annular shape by distributed winding. In this case, in the coil side portion  53 , the linear portions  83  are arranged in the circumferential direction at an interval that corresponds to a single pole pair of the magnet unit  42 , for each phase. In the coil ends  54  and  55 , the linear portions  83  of each phase are connected to each other by the turn portion  84  that is formed into a substantial V-shape. 
     In the linear portions  83  that form a pair in correspondence to a single pole pair, respective current directions are opposite each other. In addition, between one coil end  54  and the other coil end  55 , a combination of the pair of linear portions  83  that are connected by the turn portion  84  differs. As a result of the connections at the coil ends  54  and  55  being repeated in the circumferential direction, the stator winding  51  is formed into an approximately circular cylindrical shape. 
     More specifically, the stator winding  51  is that in which the winding of each phase is configured using two pairs of conductors  82  for each phase, and one three-phase winding 
     (U-phase, V-phase, and W-phase) and the other three-phase winding (X-phase, Y-phase, and Z-phase) of the stator winding  51  are provided in two layers that are on the inner side and the radially outer side. In this case, when the number of phases of the stator winding  51  is S ( 6  in the case of the example) and the number of conductors  82  per phase is m, 2×S×m=2 Sm conductors  82  are formed for each pole pair. According to the present embodiment, the number of phases S is six and the number m is four, and the rotating electric machine has eight pole pairs ( 16  poles). Therefore, 6×4×8=192 conductors  82  are arranged in the circumferential direction of the stator core  52 . 
     In the stator winding  51  shown in  FIG. 12 , in the coil side portion  53 , the linear portions  83  are arranged so as to overlap in two layers that are adjacent in the radial direction and, in the coil ends  54  and  55 , the turn portions  84  extend in the circumferential direction from the linear portions  83  that overlap in the radial direction, at directions that are opposite each other in the circumferential direction. That is, in the conductors  82  that are adjacent to each other in the radial direction, the directions of the turn portions  84  are opposite each other, excluding the end portions of the stator winding  51 . 
     Here, a winding structure of the conductors  82  in the stator winding  51  will be described in detail. According to the present embodiment, a plurality of conductors  82  that are formed by wave-winding are provide so as to overlap in a plurality of layers (such as two layers) that are adjacent in the radial direction.  FIG. 15( a )  and  FIG. 15( b )  are diagrams of an aspect of the conductors  82  in an nth layer. 
       FIG. 15( a )  shows the shape of the conductors  82  when viewed from a side of the stator winding  51 .  FIG. 15( b )  shows the shape of the conductors  82  when viewed from one axial direction side of the stator winding  51 . Here, in  FIG. 15( a )  and  FIG. 15( b ) , the positions in which the conductor groups  81  are arranged are respectively D 1 , D 2 , D 3 , . . . In addition, for convenience of description, only three conductors  82  are shown. The three conductors  82  are a first conductor  82 _A, a second conductor  82 _B, and a third conductor  82 _C. 
     In the conductors  82 _A to  82 _C, the linear portions  83  are all arranged in positions in the nth layer, that is, a same position in the radial direction. The linear portions  83  that are separated from each other by six positions (amounting to 3×m pairs) in the circumferential direction are connected to each other by the turn portion  84 . In other words, in the conductors  82 _A to  82 _C, two of both ends of seven linear portions  83  that are arrayed in an adjacent manner in the circumferential direction of the stator winding  51  on a same circle of which a center is an axial center of the rotor  40  are connected to each other by a single turn portion  84 . For example, in the first conductor  82 _A, a pair of linear portions  83  are respectively arranged in D 1  and D 7 , and the pair of linear portions  83  are connected to each other by the turn portion  84  that has an inverted V-shape. 
     In addition, the other conductors  82 _B and  82 _C are respectively arranged such that the positions in the circumferential direction are shifted by one position each in the same nth layer. In this case, because the conductors  82 _A to  82 _C are all arranged in the same layer, the turn portions  84  interfering with one another can be considered. Therefore, according to the present embodiment, an interference preventing portion in which a portion of each turn portion  84  is offset in the radial direction is formed in the turn portions  84  of the conductors  82 _A to  82 _C. 
     Specifically, the turn portion  84  of each of the conductors  82 _A to  82 _C includes a sloped portion  84   a , a peak portion  84   b , a sloped portion  84   c , and a return portion  84   d.    
     The sloped portion  84   a  is a portion that extends in the circumferential direction on a same circle (first circle). The peak portion  84   b  is shifted from the sloped portion  84   a  further towards the radially inner side (upper side in  FIG. 15( b ) ) than the same circle and reaches another circle (second circle). The sloped portion  84   c  extends in the circumferential direction on the second circle. The return portion  84 d returns from the first circle to the second circle. 
     The peak portion  84   b , the sloped portion  84   c , and the return portion  84 d correspond to the interference preventing portion. Here, the sloped portion  84   c  may be configured to shift towards the radially outer side in relation to the sloped portion  84   a . 
     In other words, the turn portion  84  of each of the conductors  82 _A to  82 _C has the sloped portion  84   a  on one side and the sloped portion  84   c  on the other side, of both sides that sandwich the peak portion  84   b  that is a center position in the circumferential direction. The positions in the radial direction of the sloped portions  84   a  and  84   c  (positions in a rearward direction on paper in  FIG. 15( a )  and positions in an up/down direction in  FIG. 15( b ) ) differ from each other. 
     For example, the turn portion  84  of the first conductor  82 _A is configured to extend along the circumferential direction with a D1 position in the nth layer as a starting position, turn to the radial direction (so as towards the radially inner side) at the peak portion  84   b  that is the center position in the circumferential direction, subsequently turn again to the circumferential direction, thereby extending again along the circumferential direction, and further, turn again to the radial direction (so as towards the radially outer side) at the returning portion  84   d , thereby reaching a D7 position in the nth layer that is a terminal position. 
     As a result of the above-described configuration, in the conductors  82 _A to  82 _C, the one sloped portions  84   a  are arrayed from top to bottom in order from the first conductor  82 _A second conductor  82 _B third conductor  82 _C. In addition, the top to bottom order of the conductors  82 _A to  82 _B is interchanged at the peak portions  84   b , and the other sloped portions  84   c  are arrayed from top to bottom in order from the third conductor  82 _C→second conductor  82 _B→first conductor  82 _A. Therefore, the conductors  82 _A to  82 _C can be arranged in the circumferential direction without interfering with one other. 
     Here, the conductor group  81  is formed by the plurality of conductors  82  being overlapped in the radial direction. In this configuration, the turn portion  84  that is connected to the linear portion  83  on the radially inner side, and the turn portion  84  that is connected to the linear portion  83  on the radially outer side, among the linear portions  83  of a plurality of layers, may be arranged so as to be further separated in the radial direction than the linear portions  84 . 
     In addition, when the conductors  82  of a plurality of layers are bent towards the same side in the radial direction at the end portions of the turn portions  84 , that is, near boundary portions with the linear portions  83 , insulation being compromised as a result of interference between the conductors  82  of adjacent layers may be prevented from occurring. 
     For example, in D 7  to D 9  in  FIG. 15( a )  and  FIG. 15( b ) , the conductors  82  that overlap in the radial direction are each bent in the radial direction at the return portion  84 d of the turn portion  84 . In this case, as shown in  FIG. 16 , a radius of curvature of a bending portion may be made to differ between the conductor  82  of the nth layer and the conductor  82  of the n+1th layer. Specifically, a radius of curvature R 1  of the conductor  82  on the radially inner side (nth layer) is less than a radius of curvature R 2  of the conductor  82  on the radially outer side (n+1th layer). 
     In addition, an amount of shifting in the radial direction may be made to differ between the conductor  82  of the nth layer and the conductor  82  of the n+1th layer. Specifically, a shift amount S 1  of the conductor  82  on the radially inner side (nth layer) is less than a shift amount S 2  of the conductor  82  on the radially outer side (n+1th layer). 
     As a result of the above-described configuration, even when the conductors  82  that overlap in the radial direction are bent in the same direction, mutual interference between the conductors  82  can be suitably prevented. As a result, favorable insulation properties can be achieved. 
     Next, the structure of the magnet unit  42  in the rotor  40  will be described. According to the present embodiment, the magnet unit  42  is made of a permanent magnet. A permanent magnet of which a remanent flux density Br=1.0 [T] and intrinsic coercive force Hcj=400 [kA/m] or greater is assumed. In short, the permanent magnet that is used according to the present embodiment is a sintered magnet in which a granular magnetic material is sintered and solidified in a mold. The intrinsic coercive force Hcj on a J-H curve is equal to or greater than 400 [kA/m], and the remnant flux density Br is equal to or greater than 1.0 [T]. 
     When 5000 to 10,000 [AT] is applied as a result of inter-phase excitation, if a permanent magnet of which a magnetic length of a single pole pair, that is, an N pole and an S pole, or in other words, a length of a path over which magnetic flux between the N pole and the S pole flows that passes through the magnet is 25 [mm] is used, Hcj=10,000 [A], indicating that demagnetization does not occur. 
     Still in other words, the magnet unit  42  is that in which saturation magnetic flux density Js is equal to or greater than 1.2 [T], grain size is equal to or less than 10 [μm], and when an orientation ratio is α, Js×α is equal to or greater than 1.0 [T]. 
     A supplementary description is provided below, regarding the magnet unit  42 . The magnet unit  42  (magnet) is characteristic in that 2.15 [T]≥Js≥1.2 [T]. In other words, as the magnet that is used in the magnet unit  42 , NdFe11TiN, Nd2Fe14B, Sm2Fe17N3, an FeNi magnet that has L10-type crystals, and the like can be given. 
     Here, compositions such as SmCo5 (samarium-cobalt), FePt, Dy2Fe14B, and CoPt cannot be used. Also, 2.15 [T]≥Js≥1.2 [T] may be met even in magnets of the same type of compounds, such as Dy2Fe14B and Nd2Fe14B, in which dysprosium that is a heavy rare earth is typically used to impart the high coercive force of Dy, while only slightly losing the high Js characteristics of neodymium. These magnets can be used in this case as well. 
     In such cases, for example, the magnet is referred to as ([Nd1-xDyx]2Fe14B). Furthermore, 2.15 [T]≥Js≥1.2 [T] can be achieved even in two or more types of magnets that have differing compositions, such as magnets that are made of two or more types of materials, such as FeNi plus Sm2Fe17N3. For example, 2.15 [T]≥Js≥1.2 [T] can be achieved even in a mixed magnet in which coercive force is increased by a small amount of Dy2Fe14B, for example, of which Js&lt;1 [T] being mixed with a Nd2Fe14B magnet of which Js=1.6[T] and has leeway in terms of Js. 
     In addition, in a rotating electric machine that operates at a temperature that is outside a range of human activity, such as 60° C. or higher that exceeds the temperatures of a desert, such as for use in a vehicle motor in which an in-vehicle temperature approaches 80° C. when left stationary in the summer, the components of FeNi and Sm2Fe17N3 of which a coefficient of temperature dependence is particularly small are preferably included. 
     A reason for this is that, in motor operation ranging from a temperature state that is close to −40° C. in Northern Europe, which is within the range of human activity, to the aforementioned 60° C. or higher that exceeds the temperatures of a desert, or to heat resistance temperatures of about 180° C. to 240° C. of a coil enamel coating, motor characteristics significantly differ based on the coefficient of temperature dependence. 
     Therefore, optimal control and the like with the same motor driver becomes difficult. Through use of FeNi that has the L10-type crystals or Sm2Fe17N3, or the like, described above, because these magnets have a coefficient of temperature dependence that is equal to or less than half that of Nd2Fe14B, load placed on the motor driver can be suitably reduced. 
     In addition, the magnet unit  42  is characteristic in that, using the above-described magnet composition, a magnitude of particle size in a fine powder state before orientation is equal to or less than 10 μm, and equal to or greater than a single magnetic-domain particle size. In a magnet, coercive force increases as a result of a particle of a powder being micronized to the order of several hundred nm. Therefore, in recent years, powder that is as micronized as possible is used. 
     However, when the powder is too fine, BH product of the magnet decreases as a result of oxidation and the like. Therefore, a particle size that is equal to or greater than the single magnet-domain particle size is preferable. When the particle size is up to the single magnet-domain particle size, it is known that coercive force increases as a result of micronization. Here, the magnitude of particle size described herein refers to the magnitude of particle size in a fine powder state in an orientation step, in terms of a manufacturing process of a magnet. 
     Furthermore, each of a first magnet  91  and a second magnet  92  of the magnet unit  42  is a sintered magnet that is formed by so-called sintering in which a magnetic powder is baked at a high temperature and hardened. This sintering is performed so that, when saturation magnetization Js of the magnet unit  42  is equal to or greater than 1.2 T, the grain size of the first magnet  91  and the second magnet  92  is equal to or less than 10 μm, and the orientation ratio is α, a condition that Js×α is equal to or greater than 1.0 T (tesla) is met. 
     In addition, the first magnet  91  and the second magnet  92  are each sintered to meet the following conditions. In addition, as a result of orientation being performed in the orientation step in the manufacturing process, unlike a definition of a magnetic force direction of an isotropic magnet as a result of a magnetizing step, the first magnet  91  and the second magnet  92  have a high orientation ratio. A high orientation ratio is set so that the saturation magnetization Js of the magnet unit  42  according to the present embodiment is equal to or greater than 1.2 T, and the orientation ratio a of the first magnet  91  and the second magnet  92  is Jr≥Js×α≥1.0 [T]. 
     Here, for example, the orientation ratio a referred to herein is, in each of the first magnet  91  or the second magnet  92 , α=⅚ when six easy axes of magnetization are present and, of the six easy axes of magnetization, five are oriented towards a direction A 10  that is a same direction and the remaining one is oriented towards a direction B 10  that is tilted by  90  degrees in relation to the direction A 10 , and α=(5+0.707)/6 when the remaining one is oriented towards a direction B 10  that is tilted by 45 degrees in relation to the direction A 10 , because the component of the remaining one that is oriented towards the direction A 10  is cos 45°=0.707. 
     In the present example, the first magnet  91  and the second magnet  92  are formed by sintering. However, if the above-described conditions are met, the first magnet  91  and the second magnet  92  may be formed by other methods. For example, a method in which an MQ3 magnet or the like is formed can be used. 
     According to the present embodiment, because a permanent magnet of which the easy axis of magnetization is controlled by orientation is used, a magnetic circuit length inside the magnet can be made longer compared to the magnetic circuit length of a conventional linear orientation magnet that outputs 1.0 [T] or greater. That is, the magnetic circuit length for a single pole pair can be achieved by a small quantity of magnets. 
     In addition, compared to a design in which the conventional linear orientation magnet is used, even when the magnet is exposed to harsh high-temperature conditions, a reversible demagnetization range thereof can be maintained. In addition, the disclosers of the present application have found a configuration in which characteristics similar to those of a polar anisotropic magnet can be achieved even through use of a magnet of a conventional technology. 
     Here, the easy axis of magnetization refers to a crystal orientation at which magnetization is facilitated in a magnet. The orientation of the easy axis of magnetization in a magnet is a direction of which the orientation ratio that indicates an extent to which the directions of the easy axes of magnetization match is equal to or greater than  50 % or a direction that is the average of the orientations of the magnet. 
     As shown in  FIG. 8  and  FIG. 9 , the magnet unit  42  is formed into a circular annular shape and is provided on the inner side of the magnet holder  41  (specifically, the radially inner side of the circular cylindrical portion  43 ). The magnet unit  42  includes the first magnet  91  and the second magnet  92  that are each a polar anisotropic magnet and of which the polarities differ from each other. The first magnet  91  and the second magnet  92  are alternately arranged in the circumferential direction. The first magnet  91  is a magnet that forms the N pole in a portion near the stator winding  51 . The second magnet  92  is a magnet that forms the S pole in a portion near the stator winding  51 . The first magnet  91  and the second magnet  92  are permanent magnets made of, for example, a rare earth magnet such as a neodymium magnet. 
     As shown in  FIG. 9 , in each of the magnets  91  and  92 , the magnetization direction extends in a circular arc shape between a d-axis (direct axis) that is a magnetic pole center in a publicly known d-q coordinate system and a q-axis (quadrature axis) that is a magnetic pole boundary between the N pole and the S pole (in other words, the magnetic flux density is  0  tesla). In each of the magnets  91  and  92 , on the d-axis side, the magnetization direction is the radial direction of the magnet unit  42  that has the circular annular shape. On the q-axis side, the magnetization direction of the magnet unit  42  that has the circular annular shape is the circumferential direction. This will be described in further detail, below. 
     As shown in  FIG. 9 , each of the magnets  91  and  92  includes a first portion  250  and two second portions  260  that are positioned on both sides of the first portion  250  in the circumferential direction of the magnet unit  42 . In other words, the first portion  250  is closer to the d-axis than the second portion  260 , and the second portion  260  is closer to the q-axis than the first portion  250 . 
     In addition, the magnet unit  42  is configured such that the direction of an easy axis of magnetization  300  in the first portion  250  is more parallel to the d-axis than the direction of an easy axis of magnetization  310  in the second portion  260 . In other words, the magnet unit  42  is configured such that an angle  011  that the easy axis of magnetization  300  in the first portion  250  forms with the d-axis is smaller than an angle θ 12  that the easy axis of magnetization  310  in the second portion  260  forms with the q-axis. 
     More specifically, the angle θ 11  is an angle that is formed by the d-axis and the easy axis of magnetization  300  when a direction from the stator  50  (armature) towards the magnet unit  42  on the d-axis is forward. The angle θ 12  is an angle that is formed by the q-axis and the easy axis of magnetization  310  when a direction from the stator  50  (armature) towards the magnet unit  42  on the q-axis is forward. Here, the angle θ 11  and the angle θ 12  are both equal to or less than 90° according to the present embodiment. 
     The easy axes of magnetization  300  and  310  herein are each based on a following definition. When, in respective portions of the magnets  91  and  92 , one easy axis of magnetization is oriented towards a direction All and another easy axis of magnetization is oriented towards a direction B  11 , an absolute value (|cosθ|) of a cosine of an angle  0  formed by the direction All and the direction B  11  is the easy axis of magnetization  300  or the easy axis of magnetization  310 . 
     That is, in each of the magnets  91  and  92 , the orientation of the easy axis of magnetization differs between the d-axis side (the portion closer to the d-axis) and the q-axis side (the portion closer to the q-axis). On the d-axis side, the orientation of the easy axis of magnetization is an orientation that is close to a direction that is parallel to the d-axis. On the q-axis side, the orientation of the easy axis of magnetization is an orientation that is close to a direction that is orthogonal to the q-axis. 
     In addition, a magnet magnetic path that has a circular arc shape is formed based on the orientations of the easy axes of magnetization. Here, in each of the magnets  91  and  92 , the easy axis of magnetization on the d-axis side may have an orientation that is parallel to the d-axis and the easy axis of magnetization on the q-axis side may have an orientation that is orthogonal to the q-axis. 
     In addition, in the magnets  91  and  92 , of the circumferential surface of each of the magnets  91  and  92 , a stator-side outer surface that is on the stator  50  side (lower side in  FIG. 9 ) and an end surface on the q-axis side in the circumferential direction serve as magnetic flux action surfaces that are inflow/outflow surfaces for the magnetic flux. The magnet magnetic path is formed so as to connect these magnetic flux action surfaces (the stator-side outer surface and the end surface on q-axis side). 
     In the magnet unit  42 , as a result of the magnets  91  and  92 , the magnetic flux flows between adjacent N and S poles in a circular arc shape. Therefore, for example, the magnet magnetic path is longer compared to that of a radial anisotropic magnet. Therefore, as shown in  FIG. 17 , the magnetic flux density distribution is close to a sine wave. As a result, unlike the magnetic flux density distribution of the radial anisotropic magnet shown as a comparative example in  FIG. 18 , the magnetic flux can be concentrated towards a center side of the magnetic pole. The torque of the rotating electric machine  10  can be increased. 
     In addition, in the magnet unit  42  according to the present embodiment, even compared to a conventional magnet that has a Halbach array, a difference in the magnetic flux density distribution is confirmed. Here, in  FIG. 17  and  FIG. 18 , a horizontal axis indicates electrical angle and a vertical axis indicates magnetic flux density. In addition, in  FIG. 17  and  FIG. 18 , 90° on the horizontal axis indicates the d-axis (that is, the magnetic pole center), and 0° and 180° on the horizontal axis indicates the q-axis. 
     That is, as a result of the magnets  91  and  92  configured as described above, the magnet magnetic flux on the d-axis is strengthened and changes in the magnetic flux near the q-axis are suppressed. As a result, the magnets  91  and  92  of which the changes in surface magnetic flux from the q-axis to the d-axis are gradual at each magnetic pole can be suitably implemented. 
     For example, the sine-wave matching ratio of the magnetic flux density distribution may be a value that is equal to or greater than 40%. As a result, compared to a case in which a radial orientation magnet or a parallel orientation magnet of which the sine-wave matching ratio is about 30% is used, the amount of magnetic flux in a waveform center portion can be improved with certainty. In addition, when the sine-wave matching ratio is equal to or greater than 60%, the amount of magnetic flux in the waveform center portion be improved with certainty compared to that of a magnetic flux concentration array such as the Halbach array. 
     In the radial anisotropic magnet shown in  FIG. 18 , the magnetic density near the q-axis sharply changes. As the change in magnetic flux density becomes sharper, the eddy currents that are generated in the stator winding  51  increase. In addition, the change in magnetic flux on the stator winding  51  side also becomes sharp. In this regard, according to the present embodiment, the magnetic flux density distribution is a magnetic flux waveform that is close to the sine wave. Therefore, near the q-axis, the change in the magnetic flux density is smaller than the change in the magnetic flux density in the radial anisotropic magnet. As a result, the generation of eddy currents can be suppressed. 
     In the magnet unit  42 , the magnetic flux is generated near the d-axis of each of the magnets  91  and  92  (that is, near the magnetic pole center) at an orientation that is orthogonal to the magnetic flux action surface  280  on the stator  50  side. The magnetic flux forms a circular arc shape that moves away from the d-axis as the magnetic flux moves away from the magnetic flux action surface  280  on the stator  50  side. 
     In addition, the magnetic flux becomes stronger as the magnetic flux becomes more orthogonal to the magnetic flux action surface. In this regard, in the rotating electric machine  10  according to the present embodiment, because the conductor groups  81  are thinner in the radial direction as described above, the center position in the radial direction of the conductor group  81  becomes close to the magnetic flux action surface of the magnet unit  42 . A strong magnetic flux can be received in the stator  50  from the rotor  40 . 
     In addition, the stator  50  is provided with the circular cylindrical stator core  52  on the radially inner side of the stator winding  51 , that is, on the side opposite the rotor  40  with the stator winding  51  therebetween. Therefore, the magnetic flux that extends from the magnetic flux action surface of each magnet  91  and  92  is drawn to the stator core  52  and circles the stator core  52  using the stator core  52  as a portion of a magnetic path. In this case, the orientation and the path of the magnet magnetic flux can be optimized. 
     Hereafter, as a manufacturing method for the rotating electric machine  10 , assembly steps for the bearing unit  20 , the housing  30 , the rotor  40 , the stator  50 , and the inverter unit  60  shown in  FIG. 5  will be described. Here, the inverter unit  60  includes the unit base  61  and the electrical components  62  as shown in  FIG. 6 . Work steps that include the assembly step for the unit base  61  and the electrical components  62  will be described. In the description below, an assembly that is made of the stator  50  and the inverter unit  60  is a first unit. An assembly that is made of the bearing unit  20 , the housing  30 , and the rotor  40  is a second unit. 
     The present manufacturing steps are: a first step of mounting the electrical components  62  on the radially inner side of the unit base  61 ; a second step of manufacturing the first unit by mounting the unit base  61  on the radially inner side of the stator  50 ; a third step of manufacturing the second unit by inserting the fixing portion  44  of the rotor  40  into the bearing unit  20  that is assembled to the housing  30 ; a fourth step of mounting the first unit on the radially inner side of the second unit; and a fifth step of fixing the housing  30  and the unit base  61  by fastening. An order of execution of these steps is the first step→second step→third step→fourth step→fifth step. 
     As a result of the above-described manufacturing method, after the bearing unit  20 , the housing  30 , the rotor  40 , the stator  50 , and the inverter unit  60  are assembled as a plurality of assemblies (sub-assemblies), these assemblies are assembled together. Therefore, ease of handling, completion of inspection for each unit, and the like can be implemented. Construction of a logical assembly line can be achieved. Therefore, multi-product production can also be easily accommodated. 
     At the first step, on at least either of the radially inner side of the unit base  61  and the outer portion in the radial direction of the electrical component  62 , a good heat conductor that provides good heat conduction may be applied by coating, bonding, or the like, and in this state, the electrical component  62  may be mounted to the unit base  61 . As a result, heat generation from the semiconductor module  66  can be efficiently transmitted to the unit base  61 . 
     At the third step, an insertion operation of the rotor  40  may be performed while a coaxial state is maintained between the housing  30  and the rotor  40 . Specifically, for example, a jig that prescribes the position of the outer circumferential surface of the rotor  40  (the outer circumferential surface of the magnet holder  41 ) or the inner circumferential surface of the rotor  40  (inner circumferential surface of the magnet unit  42 ) with reference to the inner circumferential surface of the housing  30  is used, and the housing  30  and the rotor  40  are assembled while either of the housing  30  and the rotor  40  is slid along the jig. As a result, heavy components can be assembled without imbalanced load being applied to the bearing unit  20 . Reliability of the bearing unit  20  is improved. 
     At the fourth step, the assembly of the first unit and the second unit may be performed while the coaxial state between the first unit and the second unit is maintained. Specifically, for example, a jig that prescribes the position of the inner circumferential surface of the unit base  61  with reference to the inner circumferential surface of the fixing portion  44  of the rotor  40  is used, and assembly of the units is performed while either of the first unit and the second unit is slid along the jig. As a result, because the rotor  40  and the stator  50  can be assembled while mutual interference at miniscule gaps between the rotor  40  and the stator  50  is prevented, elimination of defective products attributed to assembly, such as damage to the stator winding  51  and chipping of the permanent magnet, can be achieved. 
     The order of the above-described steps can also be the second step→third step→fourth step→fifth step→first step. In this case, the delicate electrical components  62  are assembled last. Stress applied to the electrical components  62  during the assembly step can be minimized. 
     Next, a configuration of a control system that controls the rotating electric machine  10  will be described.  FIG. 19  is an electric circuit diagram of the control system of the rotating electric machine  10 .  FIG. 20  is a functional block diagram of a control process performed by the control apparatus  110 . 
     In  FIG. 19 , two sets of three-phase windings  51   a  and  51   b  are shown as the stator winding  51 . The three-phase winding  51   a  is made of the U-phase winding, the V-phase winding, and the W-phase winding. The three-phase winding  51   b  is made of the X-phase winding, the Y-phase winding, and the Z-phase winding. For the three-phase windings  51   a  and  51   b , a first inverter  101  and a second inverter  102  that correspond to power converters are respectively provided. 
     The inverters  101  and  102  are configured by a full-bridge circuit that has a same number of upper and lower arms as the number of phases of the phase winding. Energization current is adjusted in each phase winding of the stator winding  51  by on/off of a switch (semiconductor switching element) that is provided in each arm. 
     A direct-current power supply  103  and a smoothing capacitor  104  are connected in parallel to the inverters  101  and  102 . For example, the direct-current power supply  103  is configured by an assembled battery in which a plurality of unit batteries are connected in series. Here, each switch of the inverters  101  and  102  corresponds to the semiconductor module  66  shown in  FIG. 1  and the like. The capacitor  104  corresponds to the capacitor module  68  shown in  FIG. 1  and the like. 
     The control apparatus  110  includes a microcomputer that includes a central processing unit (CPU) and various memories. The control apparatus  110  performs energization control through switching on/off of the switches in the inverters  101  and  102  based on various types of detection information of the rotating electric machine  10 , and requests for power-running drive and power generation. The control apparatus  110  corresponds to the control apparatus  77  shown in  FIG. 6 . 
     For example, the detection information of the rotating electric machine  10  includes a rotation angle (electrical angle information) of the rotor  40  that is detected by an angle detector such as resolver, a power-supply voltage (inverter input voltage) that is detected by a voltage sensor, and an energization current of each phase that is detected by a current sensor. The control apparatus  110  generates operating signals to operate the switches of the inverters  101  and  102 , and outputs the operating signals. Here, for example, the request for power generation is a request for regenerative drive when the rotating electric machine  10  is used as a vehicle power source. 
     The first inverter  101  includes a serial-connection body of an upper arm switch Sp and a lower arm switch Sn for each of the three phases that are made of the U-phase, the V-phase, and the W-phase. A high-potential-side terminal of the upper arm switch Sp of each phase is connected to a positive electrode terminal of the direct-current power supply  103 . A low-potential-side terminal of the lower arm switch Sn of each phase is connected to a negative electrode terminal (ground) of the direct-current power supply  103 . 
     One end of each of the U-phase winding, the V-phase winding, and the W-phase winding is connected to an intermediate connection point between the upper arm switch Sp and the lower arm switch Sn of each phase. These phase windings are connected by a star connection (Y connection). Other ends of the phase windings are connected to one another at a neutral point. 
     The second inverter  102  has a configuration that is similar to that of the first inverter  101 . The second inverter  102  includes a serial-connection body of an upper arm switch Sp and a lower arm switch Sn for each of the three phases that are made of the X-phase, the Y-phase, and the Z-phase. A high-potential-side terminal of the upper arm switch Sp of each phase is connected to the positive electrode terminal of the direct-current power supply  103 . A low-potential-side terminal of the lower arm switch Sn of each phase is connected to the negative electrode terminal (ground) of the direct-current power supply  103 . 
     One end of each of the X-phase winding, the Y-phase winding, and the Z-phase winding is connected to an intermediate connection point between the upper arm switch Sp and the lower arm switch Sn of each phase. These phase windings are connected by a star connection (Y connection). Other ends of the phase windings are connected to one another at a neutral point. 
       FIG. 20  shows a current feedback process for controlling the phase currents of the U-, V-, and W-phases, and a current feedback process for controlling the phase currents of the X-, Y-, and Z-phases. Here, first, the control process on the U-, V-, and W-phase side will be described. 
     In  FIG. 20 , a current command value setting unit  111  sets a d-axis current command value and a q-axis current command value based on a power-running torque command value or a power-generation torque command value for the rotating electric machine  10 , and an electrical angular velocity ω obtained by time-differentiating the electrical angle θ, using a torque-dq map. 
     Here, the current command value setting unit  111  is provided to be shared between the U-, V-, and W-phase side and the X-, Y-, and Z-phase side. Here, for example, the power-generation torque command value is a regeneration-torque command value when the rotating electric machine  10  is used as a vehicle power source. 
     A dq converting unit  112  converts a current detection value (three phase currents) from a current sensor that is provided for each phase to a d-axis current and a q-axis current that are components of an orthogonal two-dimensional rotating coordinate system in which a field direction (direction of an axis of a magnetic field or field direction) is the d-axis. 
     A d-axis current feedback control unit  113  calculates a d-axis command voltage as a manipulated variable for performing feedback control of the d-axis current to the d-axis current command value. In addition, a q-axis current feedback control unit  114  calculates a q-axis command voltage as a manipulated variable for performing feedback control of the q-axis current to the q-axis current command value. In the feedback control units  113  and  114 , the command voltages are calculated using a proportional-integral (PI) feedback method based on deviation of the d-axis current and the q-axis current from the current command values. 
     A three-phase converting unit  115  converts the d-axis and q-axis command voltages to U-phase, V-phase, and W-phase command voltages. Here, the above-described units  111  to  115  are a feedback control unit that performs feedback control of a fundamental wave current based on dq transformation. The U-phase, V-phase, and W-phase command voltages are feedback control values. 
     In addition, an operating signal generating unit  116  generates an operating signal for the first inverter  101  based on the command voltages of the three phases using a known triangular-wave-carrier comparison method. Specifically, the operating signal generating unit  116  generates a switch operating signal (duty signal) for the upper and lower arms of each phase by PWM control based on a comparison of magnitude between a signal in which the command voltages of the three phases are standardized by the power supply voltage and a carrier signal such as a triangular wave signal. 
     Moreover, a similar configuration is provided on the X-, Y-, and Z-phase side as well. A dq converting unit  122  converts a current detection value (three phase currents) from a current sensor that is provided for each phase to a d-axis current and a q-axis current that are components of an orthogonal two-dimensional rotating coordinate system in which a field direction is the d-axis. 
     A d-axis current feedback control unit  123  calculates a d-axis command voltage and a q-axis current feedback control unit  124  calculates a q-axis command voltage. A three-phase converting unit  125  converts the d-axis and q-axis command voltages to X-phase, Y-phase, and Z-phase command voltages. 
     In addition, an operating signal generating unit  126  generates an operating signal for the second inverter  102  based on the command voltages of the three phases. Specifically, the operating signal generating unit  126  generates a switch operating signal (duty signal) for the upper and lower arms of each phase by PWM control based on a comparison of magnitude between a signal in which the command voltages of the three phases are standardized by the power supply voltage and a carrier signal such as a triangular wave signal. 
     A driver  117  turns on/off the switches Sp and Sn of each of the three phases in the inverters  101  and  102  based on the switch operating signals generated in the operating signal generating units  116  and  126 . 
     Next, a torque feedback control process will be described. For example, this process is mainly used for the purpose of increasing output and reducing loss in the rotating electric machine  10  under driving conditions in which the output voltages of the inverters  101  and  102  increase, such as in a high-rotation region and a high-output region. The control apparatus  110  selects either of the torque feedback control process and the current feedback control process based on the driving conditions of the rotating electric machine  10 , and performs the selected process. 
       FIG. 21  shows the torque feedback control process that corresponds to the U-, V-, and W-phases and the torque feedback control process that corresponds to the X-, Y-, and Z-phases. Here, in  FIG. 21 , configurations that are identical to those in  FIG. 20  are given the same reference numbers. Descriptions thereof are omitted. Here, first, the control process on the U-, V-, and W-phase side will be described. 
     A voltage amplitude calculating unit  127  calculates a voltage amplitude command that is a command value for a magnitude of a voltage vector, based on the power-running torque command value or the power-generation torque command value for the rotating electric machine  10 , and the electrical angular velocity ω obtained by time-differentiating the electrical angle θ. 
     A torque estimating unit  128   a  calculates a torque estimation value that corresponds to the U-, V-, and W-phases based on the d-axis current and the q-axis current converted by the dq converting unit  112 . Here, the torque estimating unit  128   a  may calculate the voltage amplitude command based on map information in which the d-axis current, the q-axis current, and the voltage amplitude command are associated. 
     A torque feedback control unit  129   a  calculates a voltage phase command that is a command value for a phase of the voltage vector as a manipulated variable for performing feedback control of the torque estimation value to the power-running torque command value or the power-generation torque command value. In the torque feedback control unit  129   a , the voltage phase command is calculated using the PI feedback method, based on the deviation of the torque estimation value from the power-running torque command value or the power-generation torque command value. 
     An operating signal generating unit  130   a  generates the operating signal of the first inverter  101  based on the voltage amplitude command, the voltage phase command, and the electrical angle θ. Specifically, the operating signal generating unit  130   a  calculates the command voltages of the three phases based on the voltage amplitude command, the voltage phase command, and the electrical angle θ, and generates the switch operating signal for the upper and lower arms of each phase by PWM control based on a comparison of magnitude between a signal in which the calculated command voltages of the three phases are standardized by the power supply voltage and a carrier signal such as a triangular wave signal. 
     Here, the operating signal generating unit  130   a  may generate the switch operating signal based on pulse pattern information that is map information in which the voltage amplitude command, the voltage phase command, the electrical angle θ, and the switch operating signal are associated, the voltage amplitude command, the voltage phase command, and the electrical angle θ. 
     Moreover, a similar configuration is provided on the X-, Y-, and Z-phase side as well. A torque estimating unit  128   b  calculates a torque estimation value that corresponds to the X-, Y-, and Z-phases based on the d-axis current and the q-axis current converted by the dq converting unit  122 . 
     A torque feedback control unit  129   b  calculates a voltage phase command as a manipulated variable for performing feedback control of the torque estimation value to the power-running torque command value or the power-generation torque command value. In the torque feedback control unit  129   b , the voltage phase command is calculated using the PI feedback method, based on the deviation of the torque estimation value from the power-running torque command value or the power-generation torque command value. 
     An operating signal generating unit  130   b  generates the operating signal of the second inverter  102  based on the voltage amplitude command, the voltage phase command, and the electrical angle θ. Specifically, the operating signal generating unit  130   b  calculates the command voltages of the three phases based on the voltage amplitude command, the voltage phase command, and the electrical angle θ, and generates the switch operating signal for the upper and lower arms of each phase by PWM control based on a comparison of magnitude between a signal in which the calculated command voltages of the three phases are standardized by the power supply voltage and a carrier signal such as a triangular wave signal. The driver  117  turns on/off the switches Sp and Sn of each of the three phases in the inverters  101  and  102  based on the switch operating signals generated in the operating signal generating units  130   a  and  130   b.    
     Here, the operating signal generating unit  130   b  may generate the switch operating signal based on pulse pattern information that is map information in which the voltage amplitude command, the voltage phase command, the electrical angle θ, and the switch operating signal are associated, the voltage amplitude command, the voltage phase command, and the electrical angle θ. 
     Here, in the rotating electric machine  10 , occurrence of electrical corrosion in the bearings  21  and  22  in accompaniment with generation of axial current is a concern. For example, when energization of the stator winding  51  is switched by switching, distortion in the magnetic flux occurs as a result of a minute shift in switching timing (switching imbalance). 
     Electrical corrosion occurring as a result in the bearings  21  and  22  that support the rotation shaft  11  becomes a concern. The distortion in the magnetic flux occurs based on the inductance in the stator  50 . As a result of electromotive voltage in the axial direction that is generated by the distortion in the magnetic flux, insulation breakdown occurs inside the bearings  21  and  22 , and electrical corrosion progresses. 
     In this regard, according to the present embodiment, three measures that are described below are taken as electrical corrosion measures. A first electrical corrosion measure is an electrical corrosion suppression measure that is achieved by inductance being reduced in accompaniment with the stator  50  becoming coreless and the magnet magnetic flux of the magnet unit  42  being smoothed. A second electrical corrosion measure is an electrical corrosion suppression measure that is achieved by the rotation shaft having the cantilevered structure as a result of the bearings  21  and  22 . A third electrical corrosion measure is an electrical corrosion suppression measure that is achieved by the circular annular stator winding  51  being molded from a molding material together with the stator core  52 . Details of each of these measures will be separately described below. 
     First, in the first electrical corrosion measure, the stator  50  is configured to be toothless between the conductor groups  81  in the circumferential direction and provided with the sealing member  57  that is made of a non-magnetic material between the conductor groups  81 , instead of the teeth (core) (see  FIG. 10 ). 
     As a result, reduction of inductance in the stator  50  can be achieved. As a result of reduction of inductance in the stator  50  being achieved, even if a shift in switching timing occurs during energization of the stator winding  51 , the occurrence of magnetic flux distortion attributed to the shift in switching timing can be suppressed and, furthermore, electrical corrosion suppression in the bearings  21  and  22  can be performed. Here, the inductance on the d-axis may be equal to or less than the inductance on the q-axis. 
     In addition, the magnets  91  and  92  are configured to be oriented such that, on the d-axis side, the orientation of the easy axis of magnetization is parallel to the d-axis compared to the q-axis side (see  FIG. 9 ). As a result, the magnetic flux on the d-axis is strengthened. The changes in surface magnetic flux (increase/decrease in magnetic flux) from the q-axis towards the d-axis at each magnetic pole becomes gradual. Therefore, sudden changes in voltage attributed to switching imbalance is suppressed. Moreover, a configuration that contributes to electrical corrosion suppression is achieved. 
     In the second electrical corrosion measure, in the rotating electric machine  10 , the bearings  21  and  22  are arranged so as to be concentrated on one side in the axial direction in relation to a center in the axial direction of the rotor  40  (see  FIG. 2 ). As a result, compared to a configuration in which a plurality of bearings are provided on both sides in the axial direction with a rotor therebetween, the effects of electrical corrosion can be reduced. 
     That is, the rotor is double-supported by the plurality of bearings. In this configuration, a closed circuit that passes through the rotor, the stator, and each of the bearings (that is, the bearings on both sides in the axial direction sandwiching the rotor) is formed in accompaniment with generation of a high-frequency magnetic flux. Electrical corrosion of the bearings as a result of an axial current becomes a concern. In contrast, the rotor  40  is cantilever-supported by the plurality of bearings  21  and  22 . In this configuration, the above-described closed circuit is not formed. Electrical corrosion of the bearings is suppressed. 
     In addition, the rotating electric machine  10  has a following configuration in relation to the configuration for one-side arrangement of the bearings  21  and  22 . In the magnet holder  41 , the contact preventing portion that extends in the axial direction and prevents contact with the stator  50  is provided in the intermediate portion  45  that protrudes in the radial direction of the rotor  40  (see  FIG. 2 ). In this case, in cases in which a closed circuit of the axial current is formed by way of the magnet holder  41 , a closed circuit length can be lengthened and circuit resistance thereof can be increased. As a result, suppression of electrical corrosion of the bearings  21  and  22  can be achieved. 
     The holding member  23  of the bearing unit  20  is fixed to the housing on one side in the axial direction with the rotor  40  therebetween. In addition, on the other side, the housing  30  and the unit base  61  (stator holder) are coupled with each other (see  FIG. 2 ). As a result of the present configuration, the configuration in which the bearings  21  and  22  are arranged in the axial direction of the rotation shaft  11  to be concentrated on one side in the axial direction can be suitably implemented. 
     In addition, in the present configuration, the unit base  61  is connected to the rotation shaft  11  via the housing  30 . Therefore, the unit base  61  can be arranged in a position that is electrically separated from the rotation shaft  11 . Here, if an insulation member such as resin is interposed between the unit base  61  and the housing  30 , a configuration in which the unit base  61  and the rotation shaft  11  are further electrically separated is achieved. As a result, electrical corrosion of the bearings  21  and  22  can be suitably suppressed. 
     In the rotating electric machine  10  according to the present embodiment, as a result of the one-sided arrangement of the bearings  21  and  22  and the like, axial voltage that acts on the bearings  21  and  22  is reduced. In addition, a potential difference between the rotor  40  and the stator  50  is reduced. Therefore, even when a conductive grease is not used in the bearings  21  and  22 , reduction of the potential difference acting on the bearings  21  and  22  can be achieved. The conductive grease is thought to generate noise because fine particles of carbon and the like are typically included. 
     In this regard, according to the present embodiment, a non-conductive grease is used in the bearings  21  and  22 . Therefore, a disadvantage in which noise is generated in the bearings  21  and  22  can be suppressed. For example, during application to an electric vehicle such as an electric automobile, measures against noise in the rotating electric machine  10  are considered to be required. This configuration can be suitably used as such measures against noise. 
     In the third electrical corrosion measure, as a result of the stator winding  51  being molded from a molding material together with the stator core  52 , positional shifting of the stator winding  51  in the stator  50  is suppressed (see  FIG. 11 ). 
     In particular, in the rotating electric machine  10  according to the present embodiment, because a conductor-to-conductor member (teeth) is not provided between the conductor groups  81  in the circumferential direction in the stator winding  51 , concern that a positional shift may occur in the stator winding  51  can be considered. However, as a result of the stator winding  51  being molded together with the stator core  52 , shifting of the conductor position of the stator winding  51  is suppressed. Therefore, distortion in the magnetic flux as a result of a positional shift in the stator winding  51  and the occurrence of electrical corrosion in the bearings  21  and  22  as a result can be suppressed. 
     Here, the unit base  61  that serves as a housing member that fixes the stator core  51  is made of a CFRP. Therefore, for example, compared to a case in which the unit base  61  is made of aluminum or the like, electrical discharge to the unit base  61  is suppressed, and furthermore, a suitable electrical corrosion measure can be achieved. 
     In addition, as an electrical corrosion measure for the bearings  21  and  22 , at least either of the outer ring  52  and the inner ring  26  can be made of a ceramic material. Alternatively, a configuration in which an insulation sleeve is provided on the outer side of the outer ring  25  or the like can also be used. 
     Hereafter, other embodiments will be described mainly focusing on differences with the first embodiment. 
     Second Embodiment 
     According to a present embodiment, the polar anisotropic structure of the magnet unit  42  in the rotor  40  is modified. This will be described in detail, below. 
     As shown in  FIG. 22  and  FIG. 23 , the magnet unit  42  is configured using a magnet array that is referred to as a Halbach array. That is, the magnet unit  42  includes a first magnet  131  of which a magnetization direction (orientation of a magnetization vector) is the radial direction and a second magnet  132  of which the magnetization direction (orientation of a magnetization vector) is the circumferential direction. The first magnets  131  are arranged at predetermined intervals in the circumferential direction. The second magnets  132  are arranged in positions between the first magnets  131  that are adjacent in the circumferential direction. For example, the first magnet  131  and the second magnet  132  are permanent magnets that are made of a rare earth magnet such as a neodymium magnet. 
     The first magnets  131  are arranged to be separated from each other in the circumferential direction, such that the poles on the side opposing the stator  50  (inner side in the radial direction) are alternately the N pole and the S pole. In addition, the second magnets  132  are arranged such that the polarities alternate in the circumferential direction next to each of the first magnets  131 . 
     The circular cylindrical portion  43  that is provided so as to surround these magnets  131  and  132  may be a soft magnetic body core that is made of a soft magnetic material and functions as a back core. Here, in the magnet unit  42  according to the second embodiment as well, the relationship of the easy axes of magnetization in relation to the d-axis and the q-axis in the d-q coordinate system is the same as that according to the above-described first embodiment. 
     In addition, a magnetic body  133  that is made of a soft magnetic material is arranged on the radially outer side of the first magnet  131 , that is, on the side of the circular cylindrical portion  43  of the magnet holder  41 . For example, the magnetic body  133  may be made of an electromagnetic steel sheet, or a soft iron or a dust core material. In this case, a length in the circumferential direction of the magnetic body  133  is same as the length in the circumferential direction of the first magnet  131  (in particular, the length in the circumferential direction of the outer circumferential portion of the first magnet  131 ). 
     In addition, a thickness in the radial direction of an integrated body in a state in which the first magnet  131  and the magnetic body  133  are integrated is the same as the thickness in the radial direction of the second magnet  132 . In other words, the first magnet  131  has a thickness in the radial direction that is thinner than the second magnet  132  by an amount amounting to the magnetic body  133 . 
     The magnets  131  and  132  and the magnetic body  133  are mutually fixed by an adhesive or the like. The radially outer side of the first magnet  131  in the magnet unit  42  is a side opposite the stator  50 . The magnetic body  133  is provided on the side opposite the stator  50  (counter-stator side), of both sides of the first magnet  131  in the radial direction. 
     In the outer circumferential portion of the magnetic body  133 , a key  134  that serves as a protruding portion that protrudes towards the radially outer side, that is, the circular cylindrical portion  43  side of the magnet holder  41  is formed. In addition, on the inner circumferential surface of the circular cylindrical portion  43 , a key groove  135  that serves as a recessing portion that houses the key  134  of the magnetic body  133  is formed. The protruding shape of the key  134  and the groove shape of the key groove  135  are identical. In correspondence to the keys  134  that are formed in the magnetic bodies  133 , a same number of key grooves  135  as the keys  134  are formed. 
     As a result of engagement of the keys  134  and the key grooves  135 , positional shifting of the first magnet  131 , the second magnet  132 , and the magnet holder  41  in the circumferential direction (rotation direction) is suppressed. Here, the circular cylinder portion  43  of the magnet holder  41  and the magnetic body  133  in which the key  134  and the key groove  135  are provided may be arbitrary. In reverse of the description above, the key groove  135  can be provided in the outer circumferential portion of the magnetic body  133  and the key  134  can be provided in the inner circumferential portion of the circular cylindrical portion  43  of the magnet holder  41 . 
     Here, in the magnet unit  42 , as a result of the first magnets  131  and the second magnets  132  being alternately arrayed, the magnetic flux density at the first magnets  131  can be increased. Therefore, in the magnet unit  42 , concentration of the magnetic flux on one surface can occur. Magnetic flux reinforcement on the side closer to the stator  50  can be achieved. 
     In addition, as a result of the magnetic body  133  being arranged on the radially outer side of the first magnet  131 , that is, on the counter-stator side, partial magnetic saturation on the radially outer side of the first magnet  131  can be suppressed. 
     In addition, demagnetization of the first magnet  131  that occurs as a result of magnetic saturation can be suppressed. Consequently, magnetic force of the magnet unit  42  can be increased as a result. The magnet unit  42  according to the present embodiment has, so to speak, a configuration in which a portion of the first magnet  131  in which demagnetization easily occurs is replaced by the magnetic body  133 . 
       FIG. 24( a )  and  FIG. 24( b )  are diagrams that show a flow of magnetic flux in the magnet unit  42  in detail.  FIG. 24( a )  shows a case in which a conventional configuration in which the magnetic body  133  is not provided in the magnet unit  42  is used.  FIG. 24( b )  shows a case in which the configuration according to the present embodiment in which the magnetic body  133  is provided in the magnet unit  42  is used. 
     Here,  FIG. 24( a )  an  FIG. 24( b )  show the circular cylindrical portion  43  and the magnet unit  42  of the magnet holder  41  in a linearly exploded state. A lower side of the drawings is the stator side and an upper side is the counter-stator side. 
     In  FIG. 24( a ) , the magnetic flux action surface of the first magnet  131  and the side surface of the second magnet  132  are both in contact with the inner circumferential surface of the circular cylindrical portion  43 . In addition, the magnetic flux action surface of the second magnet  132  is in contact with the side surface of the first magnet  131 . In this case, a composite magnetic flux is generated in the circular cylindrical portion  43 . The composite magnetic flux is made of a magnetic flux F 1  that passes through an outer-side path of the second magnet  132  and enters the contact surface with the first magnet  131 , and a magnetic flux that is approximately parallel to the circular cylindrical portion  43  and draws the magnetic flux F 2  of the second magnet  132 . Therefore, magnetic saturation partially occurring near the contact surface of the first magnet  131  and the second magnet  132  in the circular cylindrical portion  43  is a concern. 
     In this regard, in  FIG. 24( b ) , the magnetic body  133  is provided between the magnetic flux action surface of the first magnet  131  and the inner circumferential surface of the circular cylindrical portion  43  on the side opposite the stator  50  of the first magnet  131 . Therefore, passage of magnetic flux is allowed by the magnetic body  133 . Consequently, magnetic saturation in the circular cylindrical portion  43  can be suppressed. Resistance against demagnetization is improved. 
     In addition, in  FIG. 24( b ) , unlike in  FIG. 24( a ) , magnetic flux F 2  that promotes magnetic saturation can be eliminated. As a result, permeance of the overall magnetic circuit can be effectively improved. As a result of a configuration such as this, the magnetic circuit characteristics thereof can be maintained even under harsh, high-temperature conditions. 
     Furthermore, compared to a radial magnet in a conventional SPM rotor, the magnet magnetic path that passes through the interior of the magnet is long. Therefore, magnet permeance increases. Magnetic force increases, and torque can be enhanced. Furthermore, because the magnetic flux is concentrated in the center of the d-axis, the sine-wave matching ratio can be increased. In particular, if a current waveform is a sine wave or a trapezoid wave by PWM control or a  120 -degree energization switching integrated circuit (IC) be used, the torque can be more effectively enhanced. 
     Here, in cases in which the stator core  52  is made of the electromagnetic steel sheets, the thickness in the radial direction of the stator core  52  may be ½ of the thickness in the radial direction of the magnet unit  42  or greater than ½. For example, the thickness the radial direction of the stator core  52  in may be equal to or greater than ½ of the thickness direction in the radial direction of the first magnet  131  that is provided in a magnetic pole center of the magnet unit  42 . 
     In addition, the thickness in the radial direction of the stator core  52  may be less than the thickness in the radial direction of the magnet unit  42 . In this case, the magnet magnetic flux is about 1 [T] and the saturation magnetic flux density of the stator core  52  is 2 [T]. Therefore, as a result of the thickness in the radial direction of the stator core  52  being equal to or greater than ½ of the thickness direction in the radial direction of the magnet unit  42 , magnetic flux leakage towards the inner circumferential side of the stator core  52  can be prevented. 
     In a magnet that has the Halbach structure or the polar anisotropic structure, the magnetic path has a pseudo circular-arc shape. Therefore, the magnetic flux thereof can be increased in proportion to the thickness of the magnet that covers the magnetic flux in the circumferential direction. 
     In such a configuration, the magnetic flux that flows to the stator core  52  is thought to not exceed the magnetic flux in the circumferential direction. That is, when an iron-based metal that has a saturation magnetic flux density of 2 [T] is used in relation to a magnetic flux of 1 [T] of the magnet, if the thickness of the stator core  52  is equal to or greater than half the magnet thickness, a rotating electric machine that is compact and lightweight can be suitably provided without the occurrence of magnetic saturation. 
     Here, because a diamagnetic field from the stator  50  acts on the magnet magnetic flux, the magnet magnetic flux typically becomes equal to or less than 0.9 [T]. Therefore, if the stator core has a thickness that is half that of the magnet, magnetic permeability thereof can be suitably kept high. 
     Modifications in which sections of the above-described configuration are modified will be described below. 
     (Modification 1) 
     According to the above-described embodiment, the outer circumferential surface of the stator core  52  is a curved surface with no unevenness, and a plurality of conductor groups  81  are arranged in an array at predetermined intervals on the outer circumferential surface thereof. However, this configuration may be modified. For example, as shown in  FIG. 25 , the stator core  52  has a circular annular yoke  141  and a protruding portion  142 . 
     The yoke  141  is provided on the side opposite the rotor  40  (lower side in the drawing), of both sides in the radial direction of the stator winding  51 . The protruding portion  142  extends from the yoke  141  so as to protrude towards an area between the linear portions  83  that are adjacent to each other in the circumferential direction. 
     The protruding portion  142  is provided at predetermined intervals on the radially outer side of the yoke  141 , that is, on the rotor  40  side. The conductor groups  81  of the stator winding  51  engage with the protruding portions  142  in the circumferential direction and are arranged in an array in the circumferential direction while using the protruding portions  142  as positioning portions for the conductor groups  81 . Here, the protruding portion  142  corresponds to the “conductor-to-conductor member.” 
     The protruding portion  142  is configured such that a thickness dimension in the radial direction from the yoke  141 , or in other words, as shown in  FIG. 25 , a distance W from an inner side surface  320  of the linear portion  83  that is adjacent to the yoke  141  to a peak of the protruding portion  142  in the radial direction of the yoke  141  is less than ½ of a thickness dimension (H 1  in the drawing) in the radial direction of the linear portion  83  that is adjacent to the yoke  141  in the radial direction. 
     In other words, an area that is three-fourths of a dimension (thickness) Ti of the conductor group  81  (conductive member) in the radial direction of the stator winding  51  (stator core  52 ) (twice the thickness of the conductor  82 , or in other words, a minimum distance between the surface  320  of the conductor group  81  that is in contact with the stator core  52  and a surface  330  of the conductor group  81  that faces the rotor  40 ) may be occupied by a non-magnetic member (sealing member  57 ). 
     As a result of a thickness restriction of the protruding portion  142  such as this, the protruding portions  142  do not function as teeth between the conductor groups  81  (that is, the linear portions  83 ) that are adjacent to each other in the circumferential direction, and formation of a magnetic path by the teeth does not occur. 
     The protruding portions  142  may not be provided between all of the conductor groups  81  that are arrayed in the circumferential direction. The protruding portion  142  is merely required to be provided between at least one set of conductor groups  81  that are adjacent in the circumferential direction. For example, the protruding portion  142  may be provided at equal intervals between every predetermined number of conductors groups  81  in the circumferential direction. The shape of the protruding portion  142  may be an arbitrary shape, such as a rectangle or a circular arc. 
     In addition, the linear portions  83  may be provided in a single layer on the outer circumferential surface of the stator core  52 . Therefore, in a broad sense, all that is required is that the thickness dimension in the radial direction of the protruding portion  142  from the yoke  141  be less than ½ of the thickness dimension in the radial direction of the linear portion  83 . 
     Here, when a virtual circle of which a center is the axial center of the rotation shaft  11  and that passes through a center position in the radial direction of the linear portion  83  that is adjacent to the yoke  141  in the radial direction is assumed, the protruding portion  142  may have a shape that protrudes from the yoke  141  within the range of the virtual circle, or in other words, a shape that does not protrude further towards the radially outer side (that is, the rotor  40  side) than the virtual circle. 
     As a result of the above-described configuration, the thickness dimension in the radial direction of the protruding portion  142  is limited. In addition, the protruding portion  142  does not function as the teeth between the linear portions  83  that are adjacent to each other in the circumferential direction. Therefore, compared to a case in which the teeth are provided between the linear portions  83 , the linear portions  83  that are adjacent to each other can be brought closer together. As a result, a cross-sectional area of the conductor body  82   a  can be increased. Heat generation that occurs in accompaniment with the energization of the stator winding  51  can be reduced. 
     In this configuration, alleviation of magnetic saturation can be achieved as a result of the teeth not being provided. Energization current to the stator winding  51  can be increased. In this case, increase in the amount of heat generation in accompaniment with the increase in energization current can be suitably addressed. In addition, in the stator winding  51 , the turn portion  84  includes the interference preventing portion that is shifted in the radial direction and prevents interference with another turn portion  84 . Therefore, differing turn portions  84  can be arranged so as to be separated from each other in the radial direction. As a result, improvement in heat releasability can be achieved even in the turn portions  84 . As a result of the foregoing, heat releasing performance in the stator  50  can be optimized. 
     In addition, if the yoke  141  of the stator core  52  and the magnet unit  42  of the rotor  40  (that is, the magnets  91  and  92 ) are separated by a predetermined distance or more, the thickness dimension in the radial direction of the protruding portion  142  is not bound to H 1  in  FIG. 25 . Specifically, if the yoke  141  and the magnet unit  42  are separated by 2 mm or more, the thickness dimension in the radial direction of the protruding portion  142  may be equal to or greater than H 1  in  FIG. 25 . 
     For example, when the thickness dimension in the radial direction of the linear portion  83  exceeds 2 mm and the conductor group  81  is made of two layers of conductors  82  on the inner side and the radially outer side, the protruding portion  142  may be provided over a range up to a halfway position of the linear portion  83  that is not adjacent to the yoke  141 , that is, the conductor  82  in the second layer when counted from the yoke  141 . In this case, if the thickness dimension in the radial direction of the protruding portion  142  is up to H 1 ×3/2, as a result of the cross-sectional area of the conductors of the conductor group  81  being increased, the above-described effect can approximately be achieved. 
     In addition, the stator core  52  may be configured as shown in  FIG. 26 . Here, in  FIG. 26 , the sealing member  57  is omitted. However, the sealing member  57  may be provided. In  FIG. 26 , the magnet unit  42  and the stator core  52  are shown in a linearly exploded state for convenience. 
     In  FIG. 26 , the stator  50  includes the protruding portion  142  that serves as the conductor-to-conductor member between the conductors  82  (that is, the linear portions  83 ) that are adjacent in the circumferential direction. The stator  50  includes a portion  350  that, when the stator winding  51  is energized, magnetically functions together with one of the magnetic poles (the N pole or the S pole) of the magnet unit  42  and extends in the circumferential direction of the stator  50 . 
     When a length of this portion  350  in the circumferential direction of the stator  50  is Wn, when a total width (that is, a total dimension in the circumferential direction of the stator  50 ) of the protruding portions  142  that are present in this length range Wn is Wt, the saturation magnetic flux density of the protruding portion  142  is Bs, the width dimension in the circumferential direction amounting to a single pole of the magnet unit  42  is Wm, and the residual magnetic flux density of the magnet unit  42  is Br, the protruding portion  142  is made of a magnetic material that satisfies a relationship expressed by: 
         Wt×Bs≤Wm×Br    (1).
 
     Here, the range Wn is set to include a plurality of conductor groups  81  that are adjacent in the circumferential direction and of which an excitation period overlaps. At this time, a center of the gap  56  of the conductor groups  81  is preferably set as a reference (boundary) for setting the range Wn. 
     For example, in the case of the configuration shown as an example in  FIG. 26 , the conductor groups  81  up to a fourth in order from the conductor group  81  of which the distance from the magnetic pole center of the N pole in the circumferential direction is the shortest corresponds to the foregoing plurality of conductor groups  81 . In addition, the range Wn is set to include the four conductor groups  81 . At this time, the ends of the range Wn (starting point and ending point) are the centers of the gaps  56 . 
     In  FIG. 26 , because a half of the protruding portion  142  each is included in the two ends of the range Wn, the range Wn includes a total of four protruding portions  142 . Therefore, when a width of the protruding portion  142  (that is, the dimension of the protruding portion  142  in the circumferential direction of the stator  50 , or in other words, the interval between adjacent conductor groups  81 ) is A, the total width of the protruding portions  142  that are included in the range is Wt=½A+A+A+A+½A=4A. 
     Specifically, according to the present embodiment, the three-phase winding of the stator winding  51  is a distributed winding. In the stator winding  51 , in relation to a single pole of the magnet unit  42 , the number of protrusions  142 , that is, the number of gaps  56  that are the areas between the conductor groups  81  is number of phases×Q. Here, Q refers to the number of conductors  82  that are in contact with the stator core  52  among the conductors  82  of a single phase. 
     Here, when the conductor group  81  is that in which the conductors  82  are laminated in the radial direction of the rotor  40 , Q can also be considered the number of conductors  82  on the inner circumferential side of the conductor groups  81  of a single phase. In this case, when the three-phase winding of the stator winding  51  is energized in a predetermined order of the phases, the protruding portions  14  amounting to two phases are excited within a single pole. 
     Therefore, when the width dimension in the circumferential direction of the protruding portion  142  (that is, the gap  56 ) is A, the total width dimension Wt in the circumferential direction of the protruding portions  142  that are excited by the energization of the stator winding  51  within the range of a single pole of the magnet unit  42  is number of excited phases×Q×A=2×2×A. 
     In addition, with the total width dimension Wt prescribed in this manner, in the stator core  52 , the protruding portion  142  is configured as a magnetic material that satisfies the relationship in (1), above. Here, the total width dimension Wt is also the circumferential-direction dimension of a portion within a single pole in which relative permeability may be greater than 1. 
     In addition, taking into consideration leeway, the total width dimension Wt may be the width dimension in the circumferential direction of the protruding portions  142  in a single magnetic pole. Specifically, because the number of protruding portions  142  in relation to a single pole of the magnet unit  42  is number of phases×Q, the width dimension (total width dimension Wt) in the circumferential direction of the protruding portions  412  in a single magnetic pole may be number of phases×Q×A=3×2×A=6A. 
     Here, the distributed winding referred to herein is that in which a single pole pair of the stator winding  51  is present at a single pole-pair cycle (N pole and S pole) of the magnetic poles. The single pole pair of the stator winding  51  is made of the two linear portions  83  through which currents flow in opposite directions and that are electrically connected by the turn portion  84 , and the turn portion  84 . If the above-described condition is met, even a short pitch winding is considered an equivalent of a distributed winding of a full pitch winding. 
     Next, an example of a case of a concentrated winding will be described. The concentrated winding herein is that in which the width of a single pole pair of the magnetic poles and the width of a single pole pair of the stator winding  51  differ. As examples of the concentrated winding, those in which relationships in which the conductor groups  81  in relation to a single magnetic pole pair is three, the conductor groups  81  in relation to two magnetic pole pairs is three, the conductor groups  81  in relation to four magnetic pole pairs is nine, and the conductor groups  81  in relation to five magnetic pole pairs is nine are established can be given. 
     Here, in a case in which the stator winding  51  is a concentrated winding, when the three-phase winding of the stator winding  51  is energized in a predetermined order, the stator winding  51  amounting to two phases is excited. As a result, the protruding portions  142  amounting to two phases are excited. Therefore, the width dimension Wt in the circumferential direction of the protruding portions  142  that are excited by the energization of the stator winding  51  within the range of a single pole of the magnet unit  42  is A×2. 
     In addition, with the width dimension Wt prescribed in this manner, the protruding portion  142  is configured as a magnetic material that satisfies the relationship in (1), above. Here, in the case of the concentrated winding described above, a sum of the widths of the protruding portions  142  that are present in the circumferential direction of the stator  50  in the area surrounded by the conductor groups  81  of the same phase is A. In addition, Wm in the concentrated winding corresponds to perimeter of a surface of the magnet unit  42  opposing an air gap×number of phases÷number of dispersions of the conductor group  81 . 
     Here, in a magnet of which the BH product is equal to or greater than 20 [MGOe (kJ/m{circumflex over ( )}3)], such as a neodymium magnet, a samarium cobalt magnet, or a ferrite magnet, Bd equals just over 1.0 [T]. In iron, Br equals just over 2.0 [T]. Therefore, as a high output motor, in the stator  52 , the protruding portion  142  is merely required to be made of a magnetic material that satisfies a relationship expressed by Wt&lt;½×Wm. 
     In addition, when the conductor  82  includes an outer-layer coating  182  as described hereafter, the conductors  82  may be arranged in the circumferential direction of the stator core  52  such that the outer-layer coatings  182  of the conductors  82  are in contact with each other. In this case, Wt can be considered to be  0  or the thickness of the outer-layer coatings  182  of both conductors  82  that are in contact. 
     In  FIG. 25  and  FIG. 26 , the conductor-to-conductor member (protruding portion  142 ) that is disproportionately small in relation to the magnet magnetic flux on the rotor  40  side is provided. Here, the rotor  40  is a flat surface-magnet-type rotor that has low inductance and does not have saliency in terms of magnetic resistance. In this configuration, reduction of inductance in the stator  50  can be achieved. The occurrence of magnetic flux distortion attributed to a shift in the switching timing of the stator winding  51  is suppressed. Furthermore, electrical corrosion of the bearings  21  and  22  is suppressed. 
     (Modification 2) 
     As the stator  50  that uses the conductor-to-conductor member that satisfies the relationship in expression (1), above, a following configuration can also be used. In  FIG. 27 , a tooth-like portion  143  is provided as the conductor-to-conductor member on the outer circumferential surface side (upper surface side in the drawing) of the stator core  52 . The tooth-like portion  143  is provide at a predetermined interval in the circumferential direction so as to protrude from the yoke  141  and has a thickness dimension that is the same as that of the conductor group  81  in the radial direction. A side surface of the tooth-like portion  143  is connected to the conductors  82  of the conductor group  81 . However, a gap may be provided between the tooth-like portion  143  and the conductors  82 . 
     The tooth-like portion  143  is restricted regarding the width dimension in the circumferential direction and has a thin pole tooth (stator tooth) that is disproportionate to the amount of magnets. As a result of the configuration, the tooth-like portion  143  is saturated with certainty by the magnet magnetic flux at 1.8 T or greater, and inductance can be reduced by reduction in permeance. 
     Here, in the magnet unit  42 , when a surface area for a single pole of the magnetic flux action surface on the stator side is Sm and the residual magnetic flux density of the magnet unit  42  is Br, the magnetic flux on the magnet unit side is, for example, Sm×Br. 
     In addition, when the surface area on the rotor side of each tooth-like portion  143  is St, the number of conductors  82  for a single phase is m, and the tooth-like portions  143  amounting to two phases are excited within a single pole by energization of the stator winding  51 , the magnetic flux on the stator side is, for example, St×m×2×Bs. In this case, reduction in inductance can be achieved as a result of the dimensions of the tooth-like portion  143  being restricted so as to satisfy a relationship expressed by: 
         St×m× 2 ×Bs&lt;Sm×Br    (2).
 
     Here, in a case in which the dimensions of the magnet unit  42  and the tooth-like portion  143  in the axial direction are the same, when the width dimension in the circumferential direction amounting to a single pole of the magnet unit  42  is Wm and a width dimension in the circumferential direction of the tooth-like portion  143  is Wst, expression (2) is replaced as in expression (3). 
         Wst×m× 2× Bs&lt;Wm×Br    (3)
 
     More specifically, for example, when an assumption is made that Bs=2T, Br=1T, and m=2, expression (3), above, is a relationship expressed by Wst&lt;Wm/8. In this case, reduction in induction is achieved as a result of the width dimension Wst of the tooth-like portion  143  being made less than ⅛ of the width dimension Wm amounting to a single pole of the magnet unit  42 . Here, when several m is 1, the width dimension Wst of the tooth-like portion  143  may be less than ¼ of the width dimension Wm amounting to a single pole of the magnet unit  42 . 
     Here, in expression (3), above, Wst×m×2 corresponds to the width dimension in the circumferential direction of the tooth-like portion  143  that is excited by energization of the stator winding  51  within the range of a single pole of the magnet unit  42 . 
     In  FIG. 27 , in a manner similar to the configurations in  FIG. 25  and  FIG. 25 , described above, the conductor-to-conductor member (tooth-like portion  143 ) that is disproportionately small in relation to the magnet magnetic flux on the rotor  40  side is provided. In this configuration, reduction of inductance in the stator  50  can be achieved. The occurrence of magnetic flux distortion attributed to a shift in the switching timing of the stator winding  51  is suppressed. Furthermore, electrical corrosion of the bearings  21  and  22  is suppressed. 
     (Modification 3) 
     According to the above-described embodiment, the sealing member  57  that covers the stator winding  51  is provided over a range that includes all of the conductor groups  81  on the outer side of the stator core  52  in the radial direction, that is, a range in which the thickness dimension in the radial direction becomes greater than the thickness dimension in the radial direction of the conductor group  81 . However, this configuration may be modified. 
     For example, as shown in  FIG. 28 , the sealing member  57  is configured to be provided such that a portion of the conductor  82  protrudes outward. More specifically, the sealing member  57  is configured to be provided such that a portion of the conductor  82  on the outermost side in the radial direction of the conductor group  81  is exposed towards the radially outer side, that is, the stator  50  side. In this case, the thickness dimension in the radial direction of the sealing member  57  may be same as the thickness dimension in the radial direction of the conductor group  81  or less than the thickness dimension. 
     (Modification 4) 
     As shown in  FIG. 29 , in the stator  50 , the conductor groups  81  may not be sealed by the sealing member  57 . That is, the sealing member  57  that covers the stator winding  51  is not used. In this case, the conductor-to-conductor member is not provided between the conductor groups  81  that are arrayed in the circumferential direction and gaps are formed. In short, the conductor-to-conductor member is not provided between the conductor groups  81  that are arrayed in the circumferential direction. Here, air can be considered a non-magnetic body or an equivalent of a non-magnetic body in which Bs=0. Air may be provided in the gap. 
     (Modification 5) 
     When the conductor-to-conductor member in the stator  50  is made of a non-magnetic material, a material other than resin can be used as the non-magnetic material. For example, a metal-based non-magnetic material can be used such as by SUS304 that is an austenitic stainless steel being used. 
     (Modification 6) 
     The stator  50  may not include the stator core  52 . In this case, the stator  50  is configured by the stator winding  51  shown in  FIG. 12 . Here, in the stator  50  that does not include the stator core  52 , the stator winding  51  may be sealed by a sealing material. Alternatively, the stator  50  may include a circular annular winding holding portion that is made of a non-magnetic material such as synthetic resin, instead of the stator core  52  that is made of a soft magnetic material. 
     (Modification 7) 
     According to the above-described first embodiment, the plurality of magnets  91  and  92  that are arrayed in the circumferential direction are used as the magnet unit  42  of the rotor  40 . However, this configuration may be modified. An annular magnet that is a circular annular permanent magnet may be used as the magnet unit  42 . 
     Specifically, as shown in  FIG. 30 , an annular magnet  95  is fixed on the radially inner side of the circular cylindrical portion  43  of the magnet holder  41 . A plurality of magnetic poles of which the polarities alternate in the circumferential direction are provided in the annular magnet  95 . The magnet is integrally formed on both the d-axis and the q-axis. A circular-arc-shaped magnet magnetic path of which a direction of orientation on the d-axis of the magnetic pole is the radial direction and a direction of orientation on the q-axis between magnetic poles is the circumferential direction is formed in the annular magnet  95 . 
     Here, in the annular magnet  95 , the orientation is merely required to be such that a circular-arc-shaped magnet magnetic path in which the easy axis of magnetization is parallel to the d-axis or oriented to be close to parallel to the d-axis in a portion close to the d-axis, and the easy axis of magnetization is orthogonal to the q-axis or oriented to be close to orthogonal to the q-axis in a portion close to the q-axis is formed. 
     (Modification 8) 
     In a present modification, a part of a control method of the control apparatus  110  is modified. In the present modification, sections that differ from the configuration described according to the first embodiment will mainly be described. 
     First, processes within the operating signal generating units  116  and  126  shown in  FIG. 20 , and the operating signal generating unit  130   a  and  130   b  shown in  FIG. 21  will be described with reference to  FIG. 31 . Here, the processes in the operating signal generating units  116 ,  126 ,  130   a , and  130   b  are basically similar. Therefore, the process in the operating signal generating unit  116  will be described below as an example. 
     The operating signal generating unit  116  includes a carrier generating unit  116   a  and U-, V-, and W-phase comparators  116 bU,  116 bV, and  116 bW. According to the present embodiment, the carrier generating unit  116   a  generates a triangular wave signal as a carrier signal SigC and outputs the carrier signal SigC. 
     The carrier signal SigC generated by the carrier generating unit  116   a , and the U-, V-, and W-phase command voltages calculated by the three-phase converting unit  115  are inputted to the U-, V-, and W-phase comparators  116 bU,  116 bV, and  116 bW. For example, the U-, V-, and W-phase command voltages are waveforms in the shape of sine waves, and phases are shifted from each other by 120° in electrical angles. 
     The U-, V-, and W-phase comparators  116 bU,  116 bV, and  116 bW generate the operating signals for the switches Sp and Sn of the upper arms and the lower arms of the U-, V-, and W-phases in the first inverter  101  by PWM control based on a comparison of magnitude between the U-, V-, and W-phase command voltages and the carrier signal SigC. 
     Specifically, the operating signal generating unit  116  generates the operating signals for the switches Sp and Sn of the U-, V-, and W-phases by PWM control based on a comparison of magnitude between signals in which the U-, V-, and W-phase command voltages are standardized by the power supply voltage, and the carrier signal. The driver  117  turns on/off the switches Sp and Sn of the U-, V-, and W-phases in the first inverter  101  based on the operating signals generated by the operating signal generating unit  116 . 
     The control apparatus  110  performs a process for changing the carrier frequency fc of the carrier signal SigC, that is, the switching frequency of the switches Sp and Sn. The carrier frequency fc is set to be high in a low-torque region or a high-rotation region of the rotating electric machine  10 , and set to be low in a high-torque region of the rotating electric machine  10 . This setting is performed to suppress decrease in controllability of the current that flows to each phase winding. 
     That is, reduction of inductance in the stator  50  can be achieved in accompaniment with the stator  50  being made coreless. Here, when the inductance decreases, the electrical time constant of the rotating electric machine  10  decreases. As a result, ripples in the current that flows to each phase winding may increase, controllability of the current that flows to the winding may decrease, and current control may diverge. 
     The effects of this decrease in controllability can become more pronounced when the current that flows to the winding (such as an effective value of the current) is included in a low-current region than when the current is included in a high-current region. In response to this issue, in the present modification, the control apparatus  100  changes the carrier frequency fc. 
     A process for changing the carrier frequency fc will be described with reference to  FIG. 32 . For example, this process is repeatedly performed at a predetermined control cycle by the control apparatus  110  as a process of the operating signal generating unit  116 . 
     At step S 10 , the control apparatus  110  determines whether the current that flows to the winding  51   a  of each phase is included in the low-current region. This process is a process for determining that the current torque of the rotating electric machine  10  is in the low-torque region. As a method for determining whether the current is included in the low-current region, for example, first and second methods below can be given. 
     &lt;First Method&gt; 
     The torque estimation value of the rotating electric machine  10  is calculated based on the d-axis current and the q-axis current that are converted by the dq converting unit  112 . In addition, when the calculated torque estimation value is determined to be less than a torque threshold, the current flowing to the winding  51   a  is determined to be included in the low-current region. When the torque estimation value is determined to be equal to or greater than the torque threshold, the current is determined to be included in the high-current region. Here, for example, the torque threshold may be set to ½ of a starting torque (also referred to as a locked-rotor torque) of the rotating electric machine  10 . 
     &lt;Second Method&gt; 
     When the rotation angle of the rotor  40  detected by the angle detector is determined to be equal to or greater than a speed threshold, the current that flows to the winding  51   a  is determined to be included in the low-current region, that is, the high-rotation region. Here, for example, the speed threshold may be set to a rotation speed when a maximum torque of the rotating electric machine  10  is the torque threshold. 
     When a negative determination is made at step S 10 , the control apparatus  110  determines that the current is in the high-current region and proceeds to step S 11 . At step S 11 , the control apparatus  110  sets the carrier frequency fc as a first frequency fL. 
     When an affirmative determination is made at step S 10 , the control apparatus  110  proceeds to step S 12  and sets the carrier frequency fc as a second frequency fH that is higher than the first frequency fL. 
     As a result of the present modification described above, the carrier frequency fc is set to be higher when the current that flows to each phase winding is included in the low-current region than when the current is included in the high-current region. Therefore, in the low-current region, the switching frequency of the switches Sp and Sn can be increased, and increase in current ripples can be suppressed. As a result, the decrease in current controllability can be suppressed. 
     Meanwhile, when the current that flows to each phase winding is included in the high-current region, the carrier frequency fc is set to be lower than when the current is included in the low frequency region. In the high-current region, the amplitude of the current that flows to the winding is greater than that in the low-current region. Therefore, the effect that the increase in current ripples that are attributed to the decrease in inductance has on current controllability is small. Consequently, in the high-current region, the carrier frequency fc can be set to be lower than that in the low-current region. Switching loss in the inverters  101  and  102  can be reduced. 
     In the present modification, modes described below are possible. 
     When the carrier frequency fc is set to the first frequency fL, when the affirmative determination is made at step S 10  in  FIG. 32 , the carrier frequency fc may be gradually changed from the first frequency fL towards the second frequency fH. 
     In addition, when the carrier frequency fc is set to the second frequency fH, when the negative determination is made at step S 10 , the carrier frequency fc may be gradually changed from the second frequency fH towards the first frequency fL. 
     The operating signals of the switches may be generated by space vector modulation (SVM) control, instead of PWM control. In this case as well, the changes in the switching frequency described above can be applied. 
     (Modification 9) 
     According to the above-described embodiments, the conductors configuring the conductor group  81  that are in two pairs for each phase are connected in parallel as shown in  FIG. 33( a ) .  FIG. 33( a )  is a diagram showing an electrical connection between first and second conductors  88   a  and  88   b  that are two pairs of conductors. Here, instead of the configuration shown in  FIG. 33( a ) , the first and second conductors  88   a  and  88   b  may be connected in series as shown in  FIG. 33( b ) . 
     In addition, a multiple layer conductor of three pairs or more may be arranged so as to be laminated in the radial direction.  FIG. 34  shows a configuration in which first to fourth conductors  88   a  to  88   d  that are four pairs of conductors are arranged in a laminated manner. The first to fourth conductors  88   a  to  88   d  are arranged so as to be arrayed in the radial direction in order of first, second, third, and fourth conductors  88   a ,  88   b ,  88   c , and  88   d , from the conductor closest to the stator core  52 . 
     Here, as shown in  FIG. 33( c ) , the third and fourth conductors  88   c  and  88   d  may be connected in parallel. In addition, the first conductor  88   a  may be connected to one end of this parallel-connection body and the second conductor  88   b  may be connected to the other end. When the parallel connection is used, current density in the conductors that are connected in parallel can be reduced. Heat generation during energization can be suppressed. 
     Therefore, a cylindrical stator winding is assembled to a housing (unit base  61 ) in which the cooling water passage  74  is formed. In this configuration, the first and second conductors  88   a  and  88   b  that are not connected in parallel are arranged on the stator core  52  side that is in contact with the unit base  61 , and the third and fourth conductors  88   c  and  88   d  that are connected in parallel are arranged on the counter-stator core side. As a result, the cooling performance of the conductors  88   a  to  88   d  in the multiple-layer conductor structure can be equalized. 
     Here, the thickness dimension in the radial direction of the conductor group  81  that is made of the first to fourth conductors  88   a  to  88   d  is merely required to be less than the width dimension in the circumferential direction amounting to a single phase within a single magnetic pole. 
     (Modification 10) 
     The rotating electric machine  10  may have an inner-rotor structure (inner-revolution structure). In this case, for example, inside the housing  30 , the stator  50  may be provided on the radially outer side and the rotor  40  may be provided on the radially inner side thereof. In addition, the inverter unit  60  may be provided on one side or both sides of both ends in the axial direction of the stator  50  and the rotor  40 .  FIG. 35  is a lateral cross-sectional view of the rotor  40  and the stator  50 .  FIG. 36  is a diagram showing a portion of the rotor  40  and the stator  50  in an enlarged manner. 
     The configuration in  FIG. 35  and  FIG. 36  in which the inner-rotor structure is presumed is a configuration that is similar to the configuration in  FIG. 8  and  FIG. 9  in which the outer-rotor structure is presumed, aside from the rotor  40  and the stator  50  being reversed on the inner side and the radially outer side. In brief, the stator  50  includes the stator winding  51  that has a flattened conductor structure and the stator core  52  that does not have teeth. The stator winding  51  is assembled on the radially inner side of the stator core  52 . The stator core  52  has any of the configurations below, in a manner similar to that in the case of the outer-rotor structure. 
     (A) In the stator  50 , the conductor-to-conductor member is provided between the conductor portions in the circumferential direction, and when the width dimension in the circumferential direction of the conductor-to-conductor member in a single magnetic pole is Wt, the saturation magnetic density of the conductor-to-conductor member is Bs, the width dimension in the circumferential direction of the magnet unit in a single magnetic pole is Wm, and the residual magnetic flux density of the magnet unit is Br, a magnetic material in which a relationship expressed by Wt×Bs&lt;Wm×Br is satisfied is used as the conductor-to-conductor member. 
     (B) In the stator  50 , the conductor-to-conductor member is provided between the conductor portions in the circumferential direction, and a non-magnetic material is used as the conductor-to-conductor member. 
     (C) In the stator  50 , the conductor-to-conductor member is not provided between the conductor portions in the circumferential direction. 
     In addition, the foregoing similarly applies to the magnets  91  and  92  of the magnet unit  42 . That is, the magnet unit  42  is configured using the magnets  91  and  92  are that oriented such that, on the side of the d-axis that is the magnetic pole center, the orientation of the easy axis of magnetization is parallel to the d-axis compared to the side of the q-axis that is the magnetic pole boundary. Details of the magnetization direction and the like of the magnets  91  and  92  are as described above. The annular magnet  95  (see  FIG. 30 ) can be used in the magnet unit  42 . 
       FIG. 37  is a longitudinal cross-sectional view of the rotating electric machine  10  when the rotating electric machine  10  is the inner-rotor-type.  FIG. 37  is a diagram that corresponds to  FIG. 2  that has been described earlier. Differences with the configuration in  FIG. 2  will briefly be described. 
     In  FIG. 37 , the annular stator  50  is fixed on the inner side of the housing  30 , and the rotor  40  is rotatably provided on the inner side of the rotor  50  with a predetermined air gap therebetween. In a manner similar to that in  FIG. 2 , the bearings  21  and  22  are arranged so as to be concentrated on one side in the axial direction in relation to the center in the axial direction of the rotor  40 . As a result, the rotor  40  is cantilever-supported. In addition, the inverter unit  60  is provided on the inner side of the magnet holder  41  of the rotor  40 . 
       FIG. 38  shows another configuration of the rotating electric machine  10  that has the inner-rotor structure. In  FIG. 38 , in the housing  30 , the rotation shaft  11  is rotatably supported by the bearings  21  and  22 , and the rotor  40  is fixed to the rotation shaft  11 . In a manner similar to the configuration shown in  FIG. 2  and the like, the bearings  21  and  22  are arranged so as to be concentrated on one side in the axial direction in relation to the center in the axial direction of the rotor  40 . The rotor  40  includes the magnet holder  41  and the magnet unit  42 . 
     In the rotating electric machine  10  in  FIG. 38 , as a difference with the rotor  10  in  FIG. 37 , the inverter unit  60  is not provided on the radially inner side of the rotor  40 . The magnet holder  41  is connected to the rotation shaft  11  in a position on the radially inner side of the magnet unit  42 . In addition, the stator  50  has the stator winding  51  and the stator core  52 , and is attached to the housing  30 . 
     (Modification 11) 
     Another configuration will be described as the rotating electric machine that has an inner-rotor structure.  FIG. 39  is an exploded perspective view of a rotating electric machine  200 .  FIG. 40  is a cross-sectional side view of the rotating electric machine  20 . Here, the up/down direction is indicated with reference to the state in  FIG. 39  and  FIG. 40 . 
     As shown in  FIG. 39  and  FIG. 40 , the rotating electric machine  200  includes a stator  203  and a rotor  204 . The stator  203  includes an annular stator core  201  and a multiple-phase stator winding  202 . The rotor  204  is arranged on the inner side of the stator core  201  so as to freely rotate. The stator  203  corresponds to an armature. The rotor  204  corresponds to a field element. The stator core  201  is configured by numerous silicon steel sheets being laminated. The stator winding  202  is attached to the stator core  201 . Although omitted in the drawings, the rotor  204  includes a rotor core and a plurality of permanent magnets that serve as a magnet unit. 
     A plurality of magnet insertion holes are provided in the rotor core at an even interval in the circular circumferential direction. The permanent magnets that are magnetized such that the magnetization directions alternately change for each adjacent magnetic pole are mounted in the magnet insertion holes. Here, the permanent magnet of the magnet unit may be that which has the Halbach array as described in  FIG. 23  or a configuration similar thereto. Alternatively, the permanent magnet of the magnet unit may be that which has the characteristics of polar anisotropy in which the orientation direction (magnetization direction) extends in a circular arc shape between the d-axis that is the magnetic pole center and the q-axis that is the magnetic pole boundary, such as that described in  FIG. 9  and  FIG. 30 . 
     Here, the stator  203  may have any of the configurations below. 
     (A) In the stator  203 , the conductor-to-conductor member is provided between the conductor portions in the circumferential direction, and when the width dimension in the circumferential direction of the conductor-to-conductor member in a single magnetic pole is Wt, the saturation magnetic density of the conductor-to-conductor member is Bs, the width dimension in the circumferential direction of the magnet unit in a single magnetic pole is Wm, and the residual magnetic flux density of the magnet unit is Br, a magnetic material in which a relationship expressed by Wt×Bs&lt;Wm×Br is satisfied is used as the conductor-to-conductor member. 
     (B) In the stator  203 , the conductor-to-conductor member is provided between the conductor portions in the circumferential direction, and a non-magnetic material is used as the conductor-to-conductor member. 
     (C) In the stator  203 , the conductor-to-conductor member is not provided between the conductor portions in the circumferential direction. 
     In addition, in the rotor  204 , the magnet unit is configured using a plurality of magnets that are oriented such that, on the side of the d-axis that is the magnetic pole center, the orientation of the easy axis of magnetization is parallel to the d-axis compared to the side of the q-axis that is the magnetic pole boundary. 
     An annular inverter case  211  is provided on one end side in the axial direction of the rotating electric machine  200 . The inverter case  211  is arranged such that a case lower surface is in contact with an upper surface of the stator core  201 . A plurality of power modules  212  that configure an inverter circuit, a smoothing capacitor  213  that suppresses ripples in the voltage and the current that occur as a result of the switching operation of the semiconductor switching elements, the control board  214  that has a control unit, a current sensor  215  that detects a phase current, and a resolver stator  216  that is a rotation frequency sensor for the rotor  204  are provided inside the inverter case  211 . The power modules  212  include IGBTs that are the semiconductor switching elements and diodes. 
     A power connector  217  and a signal connector  218  are provided on a peripheral edge of the inverter case  211 . The power connector  217  is connected to a direct-current circuit of a battery that is mounted in the vehicle. The signal connector  218  is used to receive and transmit various signals between the rotating electric machine  200  side and a vehicle-side control apparatus. The inverter case  211  is covered by a top cover  219 . Direct-current power from the onboard battery is inputted via the power connector  217 , converted by the switching of the power modules  212 , and supplied to the stator winding  202  of each phase. 
     A bearing unit  211  that rotatably holds the rotation shaft of the rotor  204  and an annular rear case  222  that houses the bearing unit  221  are provided on a side opposite the inverter case  211 , of both sides in the axial direction of the stator core  201 . For example, the bearing unit  211  includes two sets of bearings, and is arranged so as to be concentrated on one side in the axial direction in relation to the center in the axial direction of the rotor  204 . However, the plurality of bearings in the bearing unit  211  may be provided so as to be dispersed on both sides in the axial direction of the stator core  201 , and the rotation shaft may be double-supported by the bearings. The rotating electric machine  200  is connected to the vehicle side by the rear case  222  being fixed to an attachment portion of a gear case or a transmission of the vehicle by bolt-fastening. 
     A cooling passage  211   a  for allowing a coolant to flow is formed inside the inverter case  211 . The cooling passage  211   a  is formed by a space that is provided in an annular recessing shape from a lower surface of the inverter case  211  being sealed by the upper surface of the stator core  201 . The cooling passage  211   a  is formed so as to surround the coil end of the stator winding  202 . A module case  212   a  for the power modules  212  is inserted inside the cooling passage  211   a . A cooling passage  222   a  is also formed in the rear case  222  so as to surround the coil end of the stator winding  202 . The cooling passage  222   a  is formed by a space that is provided in an annular recessing shape from an upper surface of the rear case  222  being sealed by a lower surface of the stator core  201 . 
     (Modification 12) 
     Up to this point, configurations that are implemented in a rotation-field-type rotating electric machine have been described. However, the configuration can be modified and implemented in a rotating-armature-type rotating electric machine.  FIG. 41  shows a configuration of a rotating-armature-type rotating electric machine  230 . 
     In the rotating electric machine  230  in  FIG. 41 , a bearing  232  is fixed to each of housings  231   a  and  231   b , and a rotation shaft  233  is supported by the bearing  232  so as to freely rotate. For example, the bearing  232  is an oil-retaining bearing that includes a porous metal being permeated with oil. A rotor  234  that serves as an armature is fixed to the rotation shaft  233 . The rotor  234  includes a rotor core  235  and a multiple-phase rotor winding  236  that is fixed to an outer circumferential portion of the rotor core  235 . In the rotor  234 , the rotor core  235  has a slot-less structure. The rotor winding  236  has a flattened conductor structure. That is, the rotor winding  236  has a flattened structure in which an area for each phase is longer in the circumferential direction than the radial direction. 
     In addition, a stator  237  that serves as a field element is provided on the radially outer side of the rotor  234 . The stator  237  includes the stator core  238  that is fixed to the housing  231   a  and a magnet unit  239  that is fixed to the inner circumferential side of the stator core  238 . The magnet unit  239  is configured to include a plurality of magnetic poles of which the polarities alternate in the circumferential direction. 
     In a manner similar to the magnet unit  42  and the like described earlier, the magnet unit  239  is configured to be oriented such that, on the side of the d-axis that is the magnetic pole center, the orientation of the easy axis of magnetization is parallel to the d-axis compared to the side of the q-axis that is the magnetic pole boundary. The magnet unit  239  includes a sintered neodymium magnet that is oriented. The intrinsic coercive force thereof is equal to or greater than 400 [kA/m], and the remnant flux density Br is equal to or greater than 1.0 [T]. 
     The rotating electric machine  230  of the present example is a two-pole, three-coil brushed coreless motor. The rotor winding  236  is divided into three, and the magnet unit  239  has two poles. The number of poles and the number of coils of the brushed motor varies, such as 2:3, 4:10, or 4:21, depending on an intended use thereof. 
     A commutator  241  is fixed to the rotation shaft  233 , and a plurality of brushes  242  are arranged on the radially outer side thereof. The commutator  241  is electrically connected to the rotor winding  236  via a conductor  243  that is embedded in the rotation shaft  233 . A direct-current current flows in and out of the rotor winding  236  through the commutator  241 , the brushes  242 , and the conductor  243 . The commutator  241  is configured to be divided in the circumferential direction as appropriate, based on the number of phases of the rotor winding  236 . Here, the brushes  242  may be directly connected to a direct-current power supply such as a storage battery by electrical wiring, or may be connected to the direct-current power supply through a terminal block or the like. 
     A resin washer  244  that serves as a sealing member is provided in the rotation shaft  233 , between the bearing  232  and the commutator  241 . As a result of the resin washer  244 , oil that seeps out from the bearing  232  that is an oil-retaining bearing flowing out towards the commutator  241  side is suppressed. 
     (Modification 13) 
     In the stator winding  51  of the rotating electric machine  10 , the conductors  82  may have a plurality of insulation coatings inside and outside thereof. For example, the conductor  82  may be configured by a plurality of conductors (wires) that have insulation coatings being bundled and the bundle being covered by an outer-layer coating. 
     In this case, the insulation coatings of the wires configure the insulation coatings on the inner side. The outer-layer coating configures the insulation coating on the outer side. 
     In addition, in particular, insulation performance of the insulation coating on the outer side, among the plurality of insulation coatings of the conductor  82 , may be made higher than the insulation performance of the insulation coatings on the inner side. Specifically, a thickness of the insulation coating on the outer side is made thicker than a thickness of the insulation coatings on the inner side. 
     For example, the thickness of the insulation coating on the outer side may be 100 μm and the thickness of the insulation coating on the inner side is 40 μm. Alternatively, a material that has a lower dielectric constant than the insulation coating on the inner side may be used as the insulation coating on the outer side. All that is required is that at least either of the foregoing is applied. Here, the wire may be configured as a bundle of a plurality of conductive materials. 
     As a result of insulation on the outermost layer of the conductor  82  being strengthened as described above, the conductor  82  becomes suitable for use in a high-voltage vehicle system. In addition, appropriate driving of the rotating electric machine  10  can be achieved even on elevated regions where air pressure is low. 
     (Modification 14) 
     In the conductor  82  that includes the plurality of insulation coatings inside and outside, at least either of a rate of linear expansion (coefficient of linear expansion) and bonding strength may differ between the insulation coating on the outer side and the insulation coating on the inner side. The configuration of the conductor  82  of the present modification is shown in  FIG. 42 . 
     In  FIG. 42 , the conductor  82  includes a plurality (four in the drawing) of wires  181 , an outer-layer coating  182  (outer insulation coating) that is made of resin, for example, and surrounds the plurality of wires  181 , and an intermediate layer  183  (intermediate insulation coating) that fills an area surrounding the wires  181  inside the outer layer coating  182 . The wire  181  includes a conductive portion  181   a  that is made of a copper material and a conductor coating  181   b  (inner insulation coating) that is made of an insulation material. In terms of the stator winding, insulation is provided between phases by the outer-layer coating  182 . Here, the wiring  181  may be configured as a bundle of a plurality of conductive materials. 
     The intermediate layer  183  has a higher rate of linear expansion than the conductor coating  18  lb of the wire  181  and a lower rate of linear expansion than the outer-layer coating  182 . That is, in the conductor  82 , the rate of linear expansion increases towards the outer side. 
     In general, in the outer-layer coating  182 , the coefficient of linear expansion is higher than that of the conductor coating  181   b . As a result of the intermediate layer  183  that has a rate of linear expansion that is midway between those of the outer-layer coating  182  and the conductor coating  181   b , the intermediate layer  183  functions as a cushion material and can prevent simultaneous breakage on the outer layer side and the inner layer side. 
     Furthermore, in the conductor  82 , the conductive portion  181   a  and the conductor coating  181   b  are bonded in the wire  181 . The conductor coating  181   b  and the intermediate layer  183 , and the intermediate layer  183  and the outer-layer coating  182  are respectively bonded. In these bonded portions, bonding strength weakens towards the outer side of the conductor  82 . That is, the bonding strength between the conductive portion  181   a  and the conductor coating  181   b  is weaker than the bonding strength between the conductor coating  181   b  and the intermediate layer  183 , and the bonding strength between the intermediate layer  183  and the outer-layer coating  182 . 
     In addition, when the bonding strength between the conductor coating  181  and the intermediate layer  183  and the bonding strength between the intermediate layer  183  and the outer-layer coating  182  are compared, the latter (on the outer side) may be weaker or equal. Here, for example, a magnitude of the bonding strength between coatings can be ascertained by tensile strength that is required when the two layers of coatings are peeled apart. 
     As a result of the bonding strength of the conductor  82  being set as described above, even if an inner/outer temperature difference occurs as a result of heat generation or cooling, breakage occurring on both the inner layer side and the outer layer side (co-breakage) can be suppressed. 
     Here, heat generation and temperature changes in the rotating electric machine mainly manifest as copper loss that is heat-generated from the conductive portion  181   a  of the wire  181  and iron loss that is generated from within the core. However, these two types of losses are transmitted from the conductive portion  181   a  inside the conductor  82  or from outside the conductor  82 . A heat generation source is not present in the intermediate layer  183 . 
     In this case, as a result of the intermediate layer  183  having bonding force that can serve as a cushion for both, simultaneous breakage thereof can be prevented. Therefore, favorable usage can be achieved even for use in fields that involve high voltage resistance or significant temperature changes, such as use in vehicles. 
     A supplementary description is provided below. For example, the wire  181  may be an enamel wire. In this case, the wire  181  includes a resin coating layer (conductor coating  181   b ) made of polyamide (PA), PI, PAI, or the like. In addition, the outer-layer coating  182  on the outer side of the wire  181  is preferably made of a similar PA, PI, PAI, or the like and thick in terms of thickness. As a result, breakage of the coating due to a difference in linear expansion is suppressed. 
     Here, as the outer-layer coating  182 , in addition to that in which measures are taken by the material, such as PA, PI, or PAI being made thick, use of that in which the dielectric constant is smaller than that of PI or PAI, such as PPS, PEEK, fluororesin, polycarbonate, silicon resin, epoxy, polyethylene naphthalate, or liquid crystal polymer (LCP), is also preferred in terms of increasing conductor density in the rotating electric machine. As a result of these resins, even when the coating is thinner than a PI or PAI coating that is equivalent to the conductor coating  18  lb or of equal thickness to the conductor coating  181   b , the insulation performance thereof can be increased. As a result, an occupancy rate of the conductive portion can be increased. 
     In general, the above-described resin provides insulation in which the dielectric constant is more favorable than that of the insulation coating of the enamel wire. Of course, there are examples in which the dielectric constant is made poor due to a state of molding or adulteration. Among the foregoing, PPS and PEEK generally have a greater coefficient of linear expansion than an enamel coating. However, because the coefficient of linear expansion thereof is less than that of other resins, PPS and PEEK are suitable as the outer-layer coating in the second layer. 
     In addition, the bonding strength between the two types of coatings (intermediate insulation coating and outer-layer insulation coating) on the outer side of the wire  181  and the enamel coating of the wire  181  is preferably weaker than the bonding strength between the copper wire in the wire  181  and the enamel coating. As a result, a phenomenon in which the enamel coating and the two types of coatings break at once is suppressed. 
     When a water-cooled structure, a liquid-cooled structure, or an air-cooled structure is added to the stator, thermal stress and impact stress are thought to basically be applied from the outer-layer coating  182  and beyond. However, even in cases in which the insulation layer of the wire  181  and the above-described two types of coatings are made of differing resins, as a result of a portion in which the coatings are not bonded being provided, the thermal stress and impact stress can be reduced. 
     That is, the insulation structure is formed by a space being provided between the two types of coatings and the wire (enamel wire), and fluororesin, polycarbonate, silicon resin, epoxy, polyethylene naphthalate, or LCP being placed. In this case, the outer-layer coating and the inner-layer coating are preferably bonded using an adhesive material that has a low dielectric constant and a low coefficient of linear expansion, such as epoxy. 
     As a result, in addition to mechanical strength, coating breakage as a result of friction caused by shaking due to vibrations in the conductive portion and the like, or breakage of the outer-layer coating as a result of the difference in coefficient of linear expansion can be suppressed. 
     As an outermost-layer fixing that is generally a final step for the periphery of the stator winding and imparts mechanical strength, fixing, and the like, in relation to the conductor  82  that is configured as described above, a resin, such as epoxy, PPS, PEEK, or LCP, of which moldability is favorable and properties such as the dielectric constant and the coefficient of linear expansion are similar to the properties of the enamel coating is preferred. 
     In general, resin potting using urethane or silicon is commonly performed. However, in the above-described resin, the coefficient of linear expansion thereof differs by almost two-fold compared to other resins, and thermal stress than may shear the resin is generated. Therefore, the resin is unsuitable for use at 60 V or higher for which strict insulation regulations are internationally applied. In this regard, as a result of a final insulation step that is easily fabricated by injection molding or the like using epoxy, PPS, PEEK, LCP, or the like, the requirements described above can be achieved. 
     Modifications other than those described above are listed below. 
     A distance DM in the radial direction between a surface on the armature side in the radial direction of the magnet unit  42  and the axial center of the rotor may be equal to or greater than 50 mm. Specifically, for example, the distance DM in the radial direction between the surface on the radially inner side of the magnet unit  42  (specifically, the first and second magnets  91  and  92 ) shown in  FIG. 4  and the axial center of the rotor  40  may be equal to or greater than 50 mm. 
     As the rotating electric machine that has a slot-less structure, a small-scale rotating electric machine that is used for models of which output ranges from several tens to several hundred watts and the like is known. In addition, the disclosers of the present application have not ascertained examples in which the slot-less structure is used in a large-scale rotating electric machine for industrial use that typically exceeds  10  kW. The disclosers of the present application have examined reasons therefor. 
     The rotating electric machines that have become mainstream in recent years are largely classified into the following four types. These rotating electric machines are a brushed motor, a squirrel-cage-type induction motor, a permanent-magnet-type synchronous motor, and a reluctance motor. 
     In the brushed motor, excitation current is supplied via a brush. Therefore, in the case of a large-scale brushed motor, the brush may become large and maintenance may become complicated. As a result, there is a history in that, in accompaniment with the remarkable advancements in semiconductor technology, the brushed motors have been replaced by brushless motors such as induction motors. Meanwhile, in the field of compact motors, many coreless motors are also being supplied across the world because of advantages in terms of low inertia and economical efficiency. 
     In the squirrel-cage-type induction motor, the principle is that torque is generated by a magnetic field that is generated by a stator winding on a primary side being received by a core of a rotor on a secondary side, an induction current being sent in a concentrated manner to a squirrel-cage-type conductor, and a reaction magnetic field being formed. Therefore, from the perspective of compactness and higher efficiency of an apparatus, eliminating the core from both the stator side and the rotor side cannot necessarily be said to be expedient. 
     The reluctance motor is a motor that simply uses changes in reluctance in the core. In principle, eliminating the core is not preferable. 
     In the permanent-magnet-type synchronous motor, the IPM (that is, an embedded magnet-type rotor) has become mainstream in recent years. Unless there are special circumstances, large-scale machines in particular are often IPMs. 
     The IPM has a characteristic of having both magnet torque and reluctance torque. The IPM is operated while proportions of these torques are adjusted as appropriate by inverter control. Therefore, the IPM is a compact motor that has excellent controllability. 
     When, based on analysis by the disclosers of the present application, the torques on the rotor surface that generates the magnet torque and the reluctance torque are drawn with the distance DM in the radial direction between the surface on the armature side in the radial direction of the magnet unit and the axial center of the rotor, that is, a radius of the stator core of a typical inner rotor is taken on a horizontal axis, the torques are as shown in  FIG. 43 . 
     As shown in expression (eq1), below, whereas a potential of the magnet torque is determined by magnetic field strength generated by the permanent magnet, a potential of the reluctance torque is determined by inductance, particularly a magnitude of a q-axis inductance, as shown in expression (eq2), below. 
       Magnet torque= k·Ψ·Iq    (eq1)
 
       Reluctance torque= k ·( Lq−Ld )· Iq·Id    (eq2)
 
     Here, the magnetic field strength of the permanent magnet and the magnitude of the inductance in the winding are compared based on DM. The magnetic field strength generated by the permanent magnet, that is, a magnetic flux amount ‘I’ is proportional to a total area of the permanent magnet on a surface that opposes the stator. In the case of a circular cylindrical rotor, the total area is the surface area of a circular cylinder. 
     Strictly speaking, because the N pole and the S pole are present, the magnet field strength is proportional to an exclusive area that is half the circular cylindrical surface. The surface area of the circular cylinder is proportional to a radius of the circular cylinder and a circular cylinder length. That is, if the circular cylinder length is fixed, the surface area is proportional to the radius of the circular cylinder. 
     Meanwhile, although an inductance Lq of the winding is dependent on core shape, sensitivity is low. Rather, because the inductance Lq is proportional to a square of the number of windings of the stator winding, dependence on the number of windings is high. Here, when μ is the magnetic permeability of the magnetic circuit, N is the number of windings, S is the cross-sectional area of the magnetic circuit, and δ is an effective length of the magnetic circuit, inductance L=μ·N{circumflex over ( )}2×S/δ. 
     The number of windings of the winding is dependent on a size of a winding space. Therefore, in the case of a circular cylindrical motor, the number of windings is dependent on the winding space of the stator, that is, the slot area. As shown in  FIG. 44 , the slot area is proportional to a product a×b of a length dimension a in the circumferential direction and a length dimension b in the radial direction, because the shape of the slot is approximately a quadrangle. 
     The length dimension in the circumferential direction of the slot increases as the diameter of the circular cylinder increases. Therefore, the length dimension in the circumferential direction of the slot is proportional to the diameter of the circular cylinder. The length dimension in the radial direction of the slot is simply proportional to the diameter of the circular cylinder. That is, the slot area is proportional to a square of the diameter of the circular cylinder. 
     In addition, as is clear from expression (eq2), above, the reluctance torque is proportional to a square of the stator current. Therefore, the performance of the rotating electric machine is determined by the manner in which a large current can be supplied. The performance is dependent on the slot area of the stator. From the foregoing, if the length of the circular cylinder is fixed, the reluctance torque is proportional to the square of the diameter of the circular cylinder. With this in mind, a diagram in which a relationship between the magnetic torque, the reluctance torque, and DM is plotted is  FIG. 43 . 
     As shown in  FIG. 43 , the magnet torque linearly increases in relation to DM. The reluctance torque quadratically increases in relation to DM. Tt is clear that, when DM is relatively small, the magnet torque is dominant. The reluctance torque becomes dominant as the stator core radius increases. 
     The disclosers of the present application have reached a conclusion that, under predetermined conditions, an intersection between the magnet torque and the reluctance torque in  FIG. 43  is near a stator core radius of about 50 mm. That is, in a 10 kW-class motor in which the stator core radius sufficiently exceeds 50 mm, because use of reluctance torque is currently mainstream, eliminating the core is difficult. This is presumed to be one reason for which the slot-less structure is not used in the field of large-scale machinery. 
     In the case of a rotating electric machine in which a core is used in the stator, magnetic saturation of the core is an issue at all times. In particular, in a radial-gap-type rotating electric machine, the longitudinal cross-sectional shape of the rotation shaft is fan-shaped for each magnetic pole. A magnetic path width becomes narrower towards the inner circumferential side of the apparatus, and a dimension on the inner circumferential side of a teeth portion that forms the slots determines a performance limit of the rotating electric machine. 
     Regardless of how high performance the permanent magnet that is used is, if magnetic saturation occurs in this section, the performance of the permanent magnet cannot be sufficiently obtained. To prevent magnetic saturation from occurring in this section, the inner circumference is designed to be large, thereby resulting in a larger apparatus. 
     For example, in a distributed-winding rotating electric machine, if the winding is a three-phase winding, magnetic flux is supplied so as to be distributed among three to six teeth per magnetic pole. However, because the magnetic flux tends to become concentrated at the teeth towards the front in the circumferential direction, the magnetic flux does not flow evenly to the three to six teeth. In this case, while the magnetic flux flows in a concentrated manner to a portion (such as one or two) of the teeth, the teeth that are magnetically saturated also move in the circumferential direction in accompaniment with the rotation of the rotation shaft. This is also a factor in the generation of slot ripples. 
     From the foregoing, in the rotating electric machine that has a slot-less structure and of which DM is equal to or greater than  50  mm, the teeth are preferably eliminated to resolve magnetic saturation. However, when the teeth are eliminated, magnetic resistance in the magnetic circuit in the rotor and the stator increases, and the torque of the rotating electric machine decreases. A reason for the increase in magnetic resistance is, for example, the air gap between the rotor and the stator becoming larger. 
     Therefore, in the rotating electric machine that has the slot-less structure in which DM is equal to or greater than  50  mm, described above, there is room for improvement regarding the enhancement of torque. Therefore, there is significant merit in applying the above-described configuration that enables torque to be enhanced, to the rotating electric machine that has the slot-less structure and in which the DM is equal to or greater than  50  mm, described above. 
     Here, the distance DM in the radial direction between the surface on the armature side in the radial direction of the magnet unit and the axial center of the rotor may be equal to or greater than  50  mm in not only the rotating electric machine that has the outer-rotor structure, but also the rotating electric machine that has the inner rotor structure as well. 
     The stator winding  51  of the rotating electric machine  10  may be configured such that the linear portions  83  of the conductors  82  are provided in a single layer in the radial direction. In addition, when the linear portions  83  are arranged in a plurality of layers on the inner side and the radially outer side, the number of layers may be arbitrary. The linear portions  83  may be provided in three layers, four layers, five layers, six layers, or the like. 
     For example, in  FIG. 2 , the rotation shaft  11  is provided so as to protrude towards both one end side and the other end side of the rotating electric machine  10  in the axial direction. However, this configuration may be modified. The rotation shaft  11  may be configured to protrude towards only one end side. 
     In this case, with a portion that is cantilever-supported by the bearing unit  20  as an end portion, the rotation shaft  11  may be provided so as to extend towards the outer side in the axial direction thereof. 
     In the present configuration, because the rotation shaft  11  does not protrude inside the inverter unit  60 , an internal space of the inverter unit  60 , or specifically, the internal space of the cylindrical portion  71  can be more widely used. 
     In the rotating electric machine  10  configured as described above, a non-conductive grease is used in the bearings  21  and  22 . However, this configuration may be modified. A conductive grease may be used in the bearings  21  and  22 . For example, a conductive grease that includes metal particles, carbon particles, or the like is used. 
     As a configuration in which the rotation shaft  11  is supported so as to rotate freely, the bearings may be provided in two locations, on one end side and the other end side in the axial direction of the rotor  40 . In this case, in terms of the configuration in  FIG. 1 , the bearings may be provided in two locations, on one end side and the other end side with the inverter unit  60  therebetween. 
     In the rotating electric machine  10  configured as described above, the intermediate portion  45  of the magnet holder  41  in the rotor  40  includes the inner shoulder portion  49   a  and the annular outer shoulder portion  49   b . However, these shoulder portions  49   a  and  49   b  may be eliminated, and the intermediate portion  45  may be configured to have a flat surface. 
     In the rotating electric machine  10  configured as described above, the conductor body  82   a  is a bundle of a plurality of wires  86  in the conductor  82  of the stator winding  51 . However, this configuration may be modified. A square conductor that has a rectangular cross-section may be used as the conductor  82 . In addition, a circular conductor that has a circular cross-sectional shape or an elliptical cross-sectional shape may be used as the conductor  82 . 
     In the rotating electric machine  10  configured as described above, the inverter unit  60  is provided on the radially inner side of the stator  50 . However, instead, the inverter unit  60  may not be provided on the radially inner side of the stator  50 . In this case, an internal area that is the radially inner side of the stator  50  may be left as an empty space. In addition, a component other than the inverter unit  60  can be arranged in the internal area. 
     In the rotating electric machine  10  configured as described above, the housing  30  may not be provided. In this case, for example, the rotor  40 , the stator  50 , and the like may be held in a portion of the wheel or another vehicle component. 
     (Embodiment as an In-Wheel Motor for a Vehicle) 
     Next, an embodiment in which the rotating electric machine is provided integrally with a vehicle wheel of a vehicle as an in-wheel motor will be described. 
       FIG. 45  is a perspective view of a vehicle wheel  400  that has an in-wheel motor structure and a surrounding structure thereof.  FIG. 46  is a longitudinal cross-sectional view of the vehicle wheel  400  and the surrounding structure thereof.  FIG. 47  is an exploded perspective view of the vehicle wheel  400 . Each of these drawings is a perspective view in which the vehicle wheel  400  is viewed from inside the vehicle. 
     Here, in the vehicle, the in-wheel motor structure according to the present embodiment can be applied in various modes. For example, in a vehicle that has two wheels each in the front and rear of the vehicle, the in-wheel motor according to the present embodiment can be applied to the two wheels on the front side of the vehicle, the two wheels on the rear side of the vehicle, or the four wheels in the front and rear of the vehicle. However, the in-wheel motor according to the present embodiment can also be applied to a vehicle in which at least either of the front and rear of the vehicle has a single wheel. Here, the in-wheel motor is an application example of a drive unit for a vehicle. 
     As shown in  FIG. 45  to  FIG. 47 , for example, the vehicle wheel  400  includes a tire  401  that is a known tire that is filled with air, a wheel  402  that is fixed to an inner circumferential side of the tire  401 , and a rotating electric machine  500  that is fixed to an inner circumferential side of the wheel  402 . The rotating electric machine  500  includes a fixed portion that is a portion that includes a stator and a rotating portion that is a portion that includes a rotor. The fixed portion is fixed to a vehicle body side. 
     In addition, the rotating portion is fixed to the wheel  402 . The tire  401  and the wheel  402  rotate as a result of the rotation of the rotating unit. Here, in the rotating electric machine  500 , a detailed configuration including the fixed portion and the rotating portion will be described hereafter. 
     In addition, in the vehicle wheel  400 , as peripheral apparatuses, a suspension apparatus that holds the vehicle wheel  400  to a vehicle body (not shown), a steering apparatus that enables an orientation of the vehicle wheel  400  to be changed, and a brake apparatus that performs braking of the vehicle wheel  400  are attached. 
     The suspension apparatus is an independent-suspension-type suspension. For example, application of an arbitrary type, such as a trailing arm type, a strut type, a wishbone type, or a multilink type, is possible. According to the present embodiment, as the suspension apparatus, a lower arm  411  is provided so as to be oriented to extend towards the vehicle-body center side, and a suspension arm  412  and a spring  413  are provided so as to be oriented to extend in the up/down direction. 
     For example, the suspension arm  412  may be configured as a shock absorber. However, a detailed illustration thereof is omitted. The lower arm  411  and the suspension arm  412  are each connected to the vehicle body side and connected to a circular-disk-shaped base plate  405  that is fixed to the fixed portion of the rotating electric machine  500 . As shown in  FIG. 46 , on the rotating electric machine  500  side (base plate  405  side), the lower arm  411  and the suspension arm  412  are supported by support axes  414  and  415  so as to be in a coaxial state with each other. 
     In addition, as the steering apparatus, for example, application of a rack-and-pinion type structure or a ball-and-nut type structure, or application of a hydraulic power steering system or an electric power steering system is possible. According to the present embodiment, a rack apparatus  421  and a tie rod  422  are provided as the steering apparatus. The rack apparatus  421  is connected to the base plate  405  on the rotating electric machine  500  side by the tie rod  422 . 
     In this case, when the rack apparatus  421  is operated in accompaniment with the rotation of a steering shaft (not shown), the tie rod  422  moves in a left/right direction of the vehicle. As a result, the vehicle wheel  400  rotates around the support shafts  414  and  415  of the lower arm  411  and the suspension arm  412  and a vehicle-wheel direction is changed. 
     As the brake apparatus, application of a disk brake or a drum brake is suitable. According to the present embodiment, as the brake apparatus, a disk rotor  431  that is fixed to the rotation shaft  501  of the rotating electric machine  500  and a brake caliper  432  that is fixed to the base plate  405  on the rotating electric machine  500  side are provided. In the brake caliper  432 , a brake pad is operated by hydraulic pressure or the like. As a result of the brake pad being pressed against the disk rotor  431 , braking force caused by friction is generated and rotation of the vehicle wheel  400  is stopped. 
     In addition, a housing duct  440  that houses electrical wiring H 1  and a cooling pipe H 2  that extend from the rotating electric machine  500  is attached to the vehicle wheel  400 . The housing duct  440  is provided so as to extend from an end portion on the fixed portion side of the rotating electric machine  500 , along an end surface of the rotating electric machine  500 , and avoid the suspension arm  412 . The housing duct  440  is fixed to the suspension arm  412  in this state. 
     As a result, a connection portion to the housing duct  440  of the suspension arm  412  has a fixed positional relationship with the base plate  405 . Therefore, stress that is generated in the electrical wiring H 1  and the cooling pipe H 2  as a result of vibrations in the vehicle and the like can be suppressed. Here, the electrical wiring H 1  is connected to an onboard power supply unit and an onboard electronic control unit (ECU) (not shown). The cooling pipe H 2  is connected to a radiator (not shown). 
     Next, a configuration of the rotating electric machine  500  that is used as the in-wheel motor will be described in detail. According to the present embodiment, an example in which the rotating electric machine  500  is applied to the in-wheel motor is given. The rotating electric machine  500  has superior operation efficiency and output compared to a motor of a vehicle drive unit that has a speed reducer as in conventional technology. 
     That is, if the rotating electric machine  500  is used for a purpose that enables actualization of more practical pricing (lower pricing), compared to conventional technology, through cost reduction, the rotating electric machine  500  may also be used as a motor for purposes other than the vehicle drive unit. In such cases as well, in a manner similar to that when the rotating electric machine  500  is applied to the in-wheel motor, superior performance is exhibited. Here, operation efficiency refers to an index that is used during testing in traveling mode to derive fuel efficiency of a vehicle. 
     An overview of the rotating electric machine  500  is shown in  FIG. 48  to  FIG. 51 .  FIG. 48  is a side view of the rotating electric machine  500  viewed from a protruding side of the rotation shaft  501  (inner side of the vehicle). 
       FIG. 49  is a longitudinal cross-sectional view of the rotating electric machine  500  (a cross-sectional view taken along line  49 - 49  in  FIG. 48 ).  FIG. 50  is a lateral cross-sectional view of the rotating electric machine  500  (a cross-sectional view taken along line  50 - 50  in  FIG. 49 ).  FIG. 51  is an exploded cross-sectional view in which constituent elements of the rotating electric machine  500  are in an exploded state. In the description below, a direction in which the rotation shaft  501  extends in an outer-side direction of the vehicle body in  FIG. 51  is an axial direction. A direction that radially extends from the rotation shaft  501  is a radial direction. 
     In  FIG. 48 , on a center line that is drawn to form a cross-section  49  that passes through a center of the rotation shaft  501 , that is, a rotational center of a rotating portion, each of two directions that extend in a circumferential manner from an arbitrary point excluding the rotational center of the rotation portion, is a circumferential direction. In other words, the circumferential direction may be either of a clockwise direction and a counter-clockwise direction with an arbitrary point on the cross-section  49  as a starting point. 
     In addition, in terms of a vehicle-mounted state, a right side in  FIG. 49  is a vehicle outer side and a left side is a vehicle inner side. In other words, in terms of the vehicle-mounted state, a rotor  510  described hereafter is arranged further towards the outer-side direction of the vehicle body than a rotor cover  670 . 
     The rotating electric machine  500  according to the present embodiment is an outer-rotor-type, surface-magnet-type rotating electric machine. The rotating electric machine  500  generally includes the rotor  510 , a stator  520 , an inverter unit  530 , a bearing  560 , and the rotor cover  670 . The rotating electric machine  10  is configured by all of these components being arranged coaxially with the rotation shaft  501  that is provided integrally with the rotor  510  and assembled in the axial direction in a predetermined order. 
     In the rotating electric machine  500 , the rotor  510  and the stator  520  each have a circular cylindrical shape and are arranged so as to oppose each other with an airgap therebetween. As a result of the rotor  510  integrally rotating with the rotation shaft  501 , the rotor  510  rotates on the radially outer side of the stator  520 . The rotor  510  corresponds to a “field element.” The stator  520  corresponds to an “armature.” 
     The rotor  510  includes an approximately circular cylindrical rotor carrier  511  and an annular magnet unit  512  that is fixed to the rotor carrier  511 . The rotation shaft  501  is fixed to the rotor carrier  511 . 
     The rotor carrier  511  includes a circular cylindrical portion  513 . The magnet unit  512  is fixed to an inner circumferential surface of the inner cylindrical portion  513 . That is, the magnet unit  512  is provided so as to be surrounded by the circular cylindrical portion  513  of the rotor carrier  511  from the radially outer side. 
     In addition, the circular cylindrical portion  513  includes a first end and a second end that are opposing in the axial direction thereof. The first end is positioned in a direction on the outer side of the vehicle body. The second end is positioned in a direction in which the base plate  405  is present. In the rotor carrier  511 , the first end of the circular cylindrical portion  513  is provided so as to be continuous with an end plate  514 . 
     That is, the circular cylindrical portion  513  and the end plate  514  are an integrated structure. The second end of the circular cylindrical portion  513  is open. For example, the rotor carrier  511  is formed by a cold-rolled steel sheet (SPCC or SPHC that has a thicker plate thickness than SPCC), a forging steel, a CFRP, or the like that has sufficient mechanical strength. 
     An axial length of the rotation shaft  501  is longer than a dimension in the axial direction of the rotor carrier  511 . In other words, the rotation shaft  501  protrudes towards the open end side (vehicle inner-side direction) of the rotor carrier  511 , and the above-described brake apparatus and the like are attached to the end portion on the protruding side. 
     A through hole  514   a  is formed in a center portion of the end plate  514  of the rotor carrier  511 . The rotation shaft  501  is fixed to the rotor carrier  511  in a state in which the rotation shaft  501  is inserted into the through hole  514   a  of the end plate  514 . The rotation shaft  501  has a flange  502  that extends so as to be oriented to intersect (be orthogonal to) the axial direction in a portion in which the rotor carrier  511  is fixed. The rotation shaft  501  is fixed to the rotor carrier  511  in a state in which the flange and the surface on the vehicle outer side of the end plate  514  are surface-joined. Here, in the vehicle wheel  400 , the wheel  402  is fixed using a fastener such as a bolt that is erected in the direction of the vehicle outer side, from the flange  502  of the rotation shaft  501 . 
     In addition, the magnet unit  512  is configured by a plurality of permanent magnets that are arranged such that the polarities alternately change along the circumferential direction of the rotor  510 . As a result, the magnet unit  512  has a plurality of magnetic poles in the circumferential direction. 
     For example, the permanent magnet is fixed to the rotation carrier  511  by bonding. The magnet unit  512  has the configuration that is described as the magnet unit  42  in  FIG. 8  and  FIG. 9  according to the first embodiment. As the permanent magnet, a sintered neodymium magnet of which the intrinsic coercive force is equal to or greater than  400  [kA/m], and the remnant flux density Br is equal to or greater than 1.0 [T] is used. 
     In a manner similar to the magnet unit  42  in  FIG. 9  and the like, the magnet unit  512  includes the first magnet  91  and the second magnet  92  that are polar anisotropic magnets and of which the polarities differ from each other. 
     As described in  FIG. 8  and  FIG. 9 , in each of the magnets  91  and  92 , the orientation of the easy axis of magnetization differs between the d-axis side (the portion closer to the d-axis) and the q-axis side (the portion closer to the q-axis). On the d-axis side, the orientation of the easy axis of magnetization is an orientation that is close to a direction that is parallel to the d-axis. On the q-axis side, the orientation of the easy axis of magnetization is an orientation that is close to a direction that is orthogonal to the q-axis. In addition, a magnet magnetic path that has a circular arc shape is formed as a result of orientation based on the orientations of the easy axes of magnetization. 
     Here, in each of the magnets  91  and  92 , the easy axis of magnetization on the d-axis side may have an orientation that is parallel to the d-axis and the easy axis of magnetization on the q-axis side may have an orientation that is orthogonal to the q-axis. In short, the magnet unit  239  is configured to be oriented such that, on the side of the d-axis that is the magnetic pole center, the orientation of the easy axis of magnetization is parallel to the d-axis compared to the side of the q-axis that is the magnetic pole boundary. 
     As a result of the magnets  91  and  92 , the magnet magnetic flux on the d-axis is strengthened and changes in the magnetic flux near the q-axis are suppressed. As a result, the magnets  91  and  92  of which the changes in surface magnetic flux from the q-axis to the d-axis is gradual at each magnetic pole can be suitably implemented. As the magnet unit  512 , the configuration of the magnet unit  42  shown in  FIGS. 22 and 23 , or the configuration of the magnet unit  42  shown in  FIG. 30  can also be used. 
     Here, the magnet unit  512  may have a stator core (back yoke) that includes a plurality of electromagnetic steel sheets being laminated in the axial direction on the side of the circular cylindrical portion  513  of the rotor carrier  511 , that is, the outer circumferential surface side. That is, the rotor core may be provided on the radially inner side of the circular cylindrical portion  513  of the rotor carrier  511 , and the permanent magnet (magnets  91  and  92 ) is provided on the radially inner side of the rotor core. 
     As shown in  FIG. 47 , recessing portions  513   a  are formed in a direction that extends in the axial direction at predetermined intervals in the circumferential direction in the circular cylindrical portion  513  of the rotor carrier  511 . For example, the recessing portions  513   a  are formed by press machining. As shown in  FIG. 52 , a protruding portion  513   b  is formed on the inner circumferential surface side of the circular cylindrical portion  513 , in a position that is on a back side of the recessing portion  513   a . Meanwhile, on the outer circumferential surface side of the magnet unit  512 , the recessing portion  512   a  is formed to match the protruding portion  513   b  of the circular cylindrical portion  513   b.    
     As a result of the protruding portion  513   b  of the circular cylindrical portion  513  entering the recessing portion  512   a , positional shifting in the circumferential direction of the magnet unit  512  is suppressed. That is, the protruding portion  513  on the rotor carrier  511  side functions as a rotation stopping portion of the magnet unit  512 . Here, a method for forming the protruding portion  513   b  is arbitrary and may be other than press machining. 
     In  FIG. 52 , the direction of the magnet magnetic path in the magnet unit  512  is indicated by an arrow. The magnet magnetic path extends in a circular arc shape so as to straddle the q-axis that is the magnetic pole boundary. In addition, on the d-axis that is the magnetic pole center, the magnet magnetic path is oriented to be parallel or close to parallel to the d-axis. In the magnet unit  512 , the recessing portion  512   b  is formed for each position corresponding to the q-axis on the inner circumferential surface side. 
     In this case, in the magnet unit  512 , the length of the magnet magnetic path differs between that on a side close to the stator  520  (lower side in the drawing) and that on a side away from the stator  520  (upper side in the drawing). The length of the magnet magnetic path is shorter on the side closer to the stator  520 . The recessing portion  512   b  is formed in a position at which the length of the magnet magnetic path is the shortest. 
     That is, in the magnet unit  512 , taking into consideration the difficulty in generating sufficient magnet magnetic flux in a location in which the length of the magnet magnetic path is short, the magnet is eliminated in the location at which the magnet magnetic flux is weak. 
     Here, an effective magnetic flux density Bd of a magnet increases as a length of a magnetic circuit passing through the interior of the magnet becomes longer. In addition, a permeance coefficient Pc and the effective magnetic flux density Bd of the magnet have a relationship in which when one increases, the other increases. In  FIG. 52 , described above, reduction in the amount of magnets can be achieved while decrease in the permeance coefficient Pc that is an indicator of the magnitude of the effective magnetic flux density Bd of the magnet is suppressed. 
     Here, in B-H coordinates, an intersecting point between a permeance straight line and a demagnetization curved line based on the shape of the magnet is an operation point. The magnetic flux density at the operation point is the effective magnetic flux density Bd of the magnet. In the rotating electric machine  500  according to the present embodiment, an amount of iron in the stator  520  is reduced. In this configuration, the approach in which the magnetic circuit that straddles the q-axis is set is very effective. 
     In addition, the recessing portion  512   b  of the magnet unit  512  can be used as an air passage that extends in the axial direction. Therefore, air cooling performance can also be improved. 
     Next, the configuration of the stator  520  will be described. The stator  520  includes a stator winding  521  and a stator core  522 .  FIG. 53  is a perspective view of the stator winding  521  and the stator core  522  in an exploded state. 
     The stator winding  521  is made of a plurality of phase windings that are formed so as to be wound into an approximately cylindrical shape (annular shape). The stator core  522  that serves as a base member is assembled to the radially inner side of the stator winding  521 . According to the present embodiment, as a result phase windings of the U-phase, V-phase, and W-phase being used, the stator winding  521  is configured as phase windings of three phases. Each phase winding is configured by two layers of conductors  523  on the inner side and the radially outer side. In a manner similar to the stator  50  described earlier, the stator  520  is characterized by having a slot-less structure and a flattened conductor structure in the stator winding  521 . The stator  520  has a configuration that is similar to or like the stator  50  shown in  FIG. 8  to  FIG. 16 . 
     The configuration of the stator core  522  will be described. In a manner similar to the stator core  52  described earlier, the stator core  522  is that in which a plurality of electromagnetic steel sheets are laminated in the axial direction and has a circular cylindrical shape that has a predetermined thickness in the radial direction. The stator winding  521  is assembled to the stator core  522  on the radially outer side that is the rotor  510  side. The outer circumferential surface of the stator core  522  has a curved surface shape that has no unevenness. In a state in which the stator winding  521  is assembled thereto, the conductors  523  that configure the stator winding  521  are arranged so as to be arrayed in the circumferential direction on the outer circumferential surface of the stator core  522 . The stator core  522  functions as a back core. 
     The stator  520  may be that which uses any of (A) to (C), below. 
     (A) In the stator  520 , a conductor-to-conductor member is provided between the conductors  523  in the circumferential direction, and when the width dimension in the circumferential direction of the conductor-to-conductor member in a single magnetic pole is 
     Wt, the saturation magnetic density of the conductor-to-conductor member is Bs, the width dimension in the circumferential direction of the magnet unit  512  in a single magnetic pole is Wm, and the residual magnetic flux density of the magnet unit  512  is Br, a magnetic material in which a relationship expressed by Wt x Bs &lt;Wm x Br is satisfied is used as the conductor-to-conductor member. 
     (B) In the stator  520 , the conductor-to-conductor member is provided between the conductors  523  in the circumferential direction, and a non-magnetic material is used as the conductor-to-conductor member. 
     (C) In the stator  520 , the conductor-to-conductor member is not provided between the conductors  523  in the circumferential direction. 
     As a result of the configuration of the stator  520  such as this, inductance is reduced compared to a rotating electric machine that has a typical teeth structure in which teeth (core) for establishing a magnetic path is provided between the conductor portions that serve as the stator winding. Specifically, the inductance can be made 1/10 or less. In this case, because impedance decreases in accompaniment with the decrease in inductance, output power in relation to input power of the rotating electric machine  500  is increased. 
     Furthermore, this configuration can contribute to increase in torque. In addition, compared to a rotating electric machine that uses an embedded-magnet-type rotor in which torque output is performed using a voltage of an impedance component (in other words, using reluctance torque), a large-output rotating electric machine can be provided. 
     According to the present embodiment, the stator winding  521  is configured to be integrally molded from a molding material (insulation member) that is made of resin or the like, together with the stator core  522 . The mold material is interposed between the conductors  523  that are arrayed in the circumferential direction. Based on this structure, the stator  520  according to the present embodiment corresponds to configuration (B), among (A) to (C), described above. 
     In addition, the conductors  523  that are adjacent to each other in the circumferential direction are such that end surfaces in the circumferential direction are in contact with each other or are closely arranged with a minute gap therebetween. Based on this configuration, the stator  520  may have configuration (C), described above. Here, when configuration (A), described above, is used, a protruding portion may be provided on the outer circumferential surface of the stator core  522  to match an orientation of the conductors  523  in the axial direction, that is, for example, to match a skew angle if the stator winding  521  has a skewed structure. 
     Next, the configuration of the stator winding  521  will be described with reference to  FIG. 54 .  FIG. 54  is a front view in which the stator winding  521  is expanded in a planar manner.  FIG. 54( a )  shows each conductor  523  that is positioned on the outer layer in the radial direction.  FIG. 54( b )  shows each conductor  523  that is positioned in the inner layer in the radial direction. 
     The stator winding  521  is formed by being wound into a circular annular shape by distributed winding. In the stator winding  521 , a conductor material is wound in two layers on the inner side and the radially outer side. In addition, skewing is applied in differing directions between the conductors  523  on the inner layer side and the outer layer side (see  FIG. 54( a )  and  FIG. 54( b ) ). The conductors  523  are mutually insulated. The conductor  523  may be configured as a bundle of a plurality of wires  86  (see  FIG. 13 ). 
     In addition, for example, the conductors  523  that are of a same phase and that have a same energization direction are provided so as to be arrayed two at a time in the circumferential direction. In the stator winding  521 , a single conductor portion of the same phase is configured by the conductors  523  that are in two layers in the radial direction and two conductors in the circumferential direction (that is, a total of four conductors). The conductor portion is provided one each within a single magnetic pole. 
     In the conductor portion, a thickness dimension in the radial direction thereof is preferably smaller than a width dimension in the circumferential direction amounting to a single phase within a single magnetic pole. The stator winding  521  preferably has a flattened conductor structure, as a result. Specifically, for example, in the stator winding  521 , a single conductor portion of the same phase may be configured by the conductors  523  that are in two layers in the radial direction and four conductors in the circumferential direction (that is, a total of eight conductors). 
     Alternatively, on a conductor cross-section of the stator winding  521  shown in  FIG. 50 , the width dimension in the circumferential direction may be greater than the thickness dimension in the radial direction. The stator winding  51  shown in  FIG. 12  can also be used as the stator winding  521 . However, in this case, a space for housing the coil end of the stator winding is required to be secured inside the rotor carrier  511 . 
     In the stator winding, the conductors  523  are arranged in an array in the circumferential direction so as to be tilted at a predetermined angle in relation to the stator core  522 , in coil sides  525  that overlap on the inner side and the radially outer side. In addition, the conductors  523  are reversed (doubled back) towards the inner side in the axial direction at coil ends  526  on both sides that are further on the outer side in the axial direction than the stator core  522 , and continuously connected. 
     In  FIG. 54( a ) , an area that serves as the coil side  525  and an area that serves as the coil end  526  are each shown. The conductor  523  on the inner layer side and the conductor  523  on the outer layer side are connected to each other at the coil end  526 . As a result, each time the conductor  523  is reversed (each time the conductor  523  is doubled back) in the axial direction at the coil end  526 , the conductor  523  alternately switches between the inner layer side and the outer layer side. In other words, the stator winding  521  is configured such that, in the conductors  523  that are continuous in the circumferential direction, switching between inner and outer layers is performed to match a reversal of a direction of a current. 
     In addition, in the stator winding  521 , two types of skewing of which skew angles differ between that of end portion areas that are both ends in the axial direction and that of a center area that is sandwiched between the end portion areas are applied. 
     That is, as shown in  FIG. 55 , in the conductor  523 , a skew angle θs 1  of the center area and a skew angle θs 2  of the end portion area differ. The skew angle θs 1  is smaller than the skew angle θs 2 . The end portion area is prescribed as an area that includes the coil side  525  in the axial direction. The skew angle θs 1  and the skew angle θs 2  are tilt angles at which the conductors  523  are tilted in relation to the axial direction. The skew angle θs 1  of the center area may be prescribed to be an angle range that is appropriate for eliminating harmonic components of the magnetic flux that are generated as a result of energization of the stator winding  521 . 
     As a result of the skew angles of the conductor  523  in the stator winding  521  differing between that of the center area and that of the end portion areas, and the skew angle θs 1  of the center area being smaller than the skew angle θs 2  of the end portion areas, a winding factor of the stator winding  521  can be increased while reduction of the coil end  526  is achieved. 
     In other words, a length of the coil end  526 , that is, a conductor length of the portion that projects out from the stator core  522  in the axial direction can be shortened while a desired winding factor is ensured. As a result, torque enhancement can be implemented while size reduction of the rotating electric machine  50  is achieved. 
     Here, an appropriate range of the skew angle θs 1  of the center area will be described. When an X-number of conductors  523  are arranged within a single magnetic pole in the stator winding  521 , an X-order harmonic component being generated as a result of the energization of the stator winding  521  can be considered. When the number of phases is S and the number of pairs is m, X=2×S×m. 
     The disclosers of the present application have focused on the following. That is, because the X-order harmonic component is a component that composes a composite wave of an X−1-order harmonic component and an X+1-order harmonic component, the X-order harmonic component can be reduced as a result of at least either of the X−1-order harmonic component and the X+1-order harmonic component being reduced. In light of this focus, the disclosers of the present application have found that the X-order harmonic component can be reduced as a result of the skew angle θs 1  being set within an angle range of 360°/(X+1) to 360°/(X−1) in electrical angles. 
     For example, when S=3 and m=2, to reduce the harmonic component of X=12th order, the skew angle θs 1  is set within an angle range of 360°/13 to 360°/11. That is, the skew angle θs 1  may be set to an angle within a range of 27.7° to 32.7°. 
     As a result of the skew angle θs 1  of the center area being set as described above, in the center area, the NS-alternating magnet magnetic flux can be actively interlinked. The winding factor of the stator winding  521  can be increased. 
     The skew angle θs 2  of the end portion area is an angle that is greater than the skew angle θs 1  of the center area, described above. In this case, the angle range of the skew angle θs 2  is θs 1 &lt;θs 2 &lt;90°. 
     In addition, in the stator winding  521 , the conductor  523  on the inner layer side and the conductor  523  on the outer layer side may be connected by welding or bonding of the end portions of the conductors  523 . Alternatively, the conductor  523  on the inner layer side and the conductor  523  on the outer layer side may be connected by bending them. In the stator winding  521 , the end portion of each phase winding is electrically connected to a power converter (inverter) by a bus bar or the like in the coil end  526  on one side (that is, one end side in the axial direction), of the coil ends  526  on both sides in the axial direction. Therefore, here, a configuration in which the conductors are connected to each other in the coil end  526  will be described, while differentiation is made between the coil end  526  on the bus-bar connection side and the coil end  526  on an opposite side thereof. 
     As a first configuration, the conductors  523  are connected by welding in the coil ends  526  on the bus-bar connection side, and the conductors  523  are connected by a means other than welding in the coil ends  526  on the opposite side thereof. 
     For example, as a means other than welding, connection by bending of the conductor material can be considered. In the coil end  526  on the bus-bar connection side, the bus bar being welded to the end portions of the phase windings can be assumed. Therefore, as a result of the configuration in which the conductors  523  are connected by welding in the same coil end  526  thereof, the welding portion can be performed in a series of steps and work efficiency can be improved. 
     As a second configuration, the conductors  523  are connected by a means other than welding in the coil ends  536  on the bus-bar connection side, and the conductors  523  are connected by welding in the coil ends  526  on the opposite side thereof. 
     In this case, if the conductors  523  are connected by welding in the coil ends  526  on the bus-bar connection side, a need to keep sufficient separation distance between the bus bar and the coil ends  526  to prevent contact between the welding portion and the bus bar arises. However, as a result of the present configuration, the separation distance between the bus bar and the coil ends  526  can be reduced. As a result, restrictions related to the length of the stator winding  521  in the axial direction or the bus bar can be relaxed. 
     As a third configuration, the conductors  523  are connected by welding in the coil ends  526  on both sides in the axial direction. In this case, all of the conductor materials that are prepared before welding can be of a short wire length. Improvement in work efficiency can be achieved through elimination of a bending step. 
     As a fourth configuration, the conductors  523  are connected by a means other than welding in the coil ends  526  on both sides in the axial direction. In this case, sections in which welding is performed can be minimized in the stator winding  521 . Concern regarding insulation peeling occurring at a welding step can be reduced. 
     In addition, at a step of fabricating the circular annular stator winding  521 , a strip-shaped winding that is aligned in a planar shape may be fabricated, and the strip-shaped winding may subsequently be formed into an annular shape. In this case, in a state in which the stator winding is in the form of the planar, strip-shaped winding, welding of the conductors at the coil ends  526  may be performed as required. 
     When the planar, strip-shaped winding is formed into the annular shape, the strip-shaped winding may be formed into an annular shape using a circular columnar tool that has a same diameter as the stator core  522 , by the winding being wrapped around the circular columnar tool. Alternatively, the strip-shaped winding may be directly wrapped around the stator core  522 . 
     Here, the configuration of the stator winding  521  can also be modified in the following manner. 
     For example, in the stator winding  521  shown in  FIG. 54( a )  and (b), the skew angles of the center area and the end portion area may be the same. 
     In addition, in the stator winding  521  shown in  FIG. 54( a )  and (b), the end portions of the conductors  523  of the same phase that are adjacent to each other in the circumferential direction may be connected to each other by a crossover wire that extends in a direction that is orthogonal to the axial direction. 
     The number of layers of the stator winding  521  is merely required to be  2  x n layers (n being a natural number). The stator winding  521  can have four layers, six layers, or the like, in addition to two layers. 
     Next, the inverter unit  530  that is a power conversion unit will be described. Here, a configuration of the inverter unit  530  will be described with reference to  FIGS. 56 and 57  that are exploded cross-sectional views of the inverter unit  530 . Here,  FIG. 57  shows components shown in  FIG. 56  as two subassemblies. 
     The inverter unit  530  includes an inverter housing  531 , a plurality of electrical modules  532  that are assembled to the inverter housing  531 , and a bus bar module  533  that electrically connects the electrical modules  532 . 
     The inverter housing  531  includes an outer wall member  541 , an inner wall member  542 , and a boss formation member  543 . The outer wall member  541  has a circular cylindrical shape. The inner wall member  542  has a circular cylindrical shape of which an outer circumference diameter is smaller than a diameter of the outer wall member  541 , and is arranged on the radially inner side of the outer wall member  541 . The boss formation member  543  is fixed to one end side in the axial direction of the inner wall member  542 . 
     The members  541  to  543  are preferably made of a conductive material, and for example, is made of a CFRP. The inverter housing  531  is configured by the outer wall member  541  and the inner wall member  542  being assembled so as to be overlapped on the inner side and the radially outer side, and the boss formation member  543  being assembled to one end side in the axial direction of the inner wall member  542 . This assembled state is the state shown in  FIG. 57 . 
     The stator core  522  is fixed to the radially outer side of the outer wall member  541  of the inverter housing  531 . As a result, the stator  520  and the inverter unit  530  are integrated. 
     As shown in  FIG. 56 , a plurality of recessing portions  541   a ,  541   b , and  541   c  are formed on an inner circumferential surface of the outer wall member  541 . In addition, a plurality of recessing portions  542   a ,  542   b , and  542   c  are formed on an outer circumferential surface of the inner wall member  542 . Furthermore, as a result of the outer wall member  541  and the inner wall member  542  being assembled together, three hollow portions  544   a ,  544   b , and  544   c  are formed between the outer wall member  541  and the inner wall member  542  (see  FIG. 57 ). 
     Among the hollow portions  544   a ,  544   b , and  544   c , the hollow portion  544   b  in the center is used as a cooling water passage  545  through which cooling water that serves as a coolant flows. In addition, a sealing member  546  is housed in the hollow portions  544   a  and  544   c  on both sides sandwiching the hollow portion  544   b  (cooling water passage  545 ). The hollow portion  544   b  (cooling water passage  545 ) is sealed as a result of the sealing member  546 . The cooling water passage  545  will be described in detail hereafter. 
     In addition, in the boss formation member  543 , an end plate  547  that has a circular-disk ring shape, and a boss portion  548  that protrudes from the end plate  547  towards a housing interior are provided. The boss portion  548  is provided in a hollow cylindrical shape. 
     For example, as shown in  FIG. 51 , of a first end of the inner wall member  542  in the axial direction and a second end on the protruding side (that is, the vehicle inner side) of the rotation shaft  501  that opposes the first end, the boss formation member  543  is fixed to the second end. Here, in the vehicle wheel  400  shown in  FIGS. 45 to 47 , the base plate  405  is fixed to the inverter housing  531  (more specifically, the end plate  547  of the boss formation member  543 ). 
     The inverter housing  531  is configured to have a double layer of peripheral walls in the radial direction with the axial center as a center. The peripheral wall on the outer side of the double layer of peripheral walls is formed by the outer wall member  541  and the inner wall member  542 . The peripheral wall on the inner side is formed by the boss portion  548 . 
     Here, in the description below, the peripheral wall on the outer side that is formed by the outer wall member  541  and the inner wall member  542  is also referred to as an “outer peripheral wall WA 1 ,” and the peripheral wall on the inner side that is formed by the boss portion  548  is also referred to as an “inner peripheral wall WA 2 .” 
     An annular space is formed between the outer peripheral wall WA 1  and the inner peripheral wall WA 2  in the inverter housing  531 . The plurality of electrical modules  532  are arranged so as to be arrayed in the circumferential direction inside the annular space. The electrical module  532  is fixed to the inner circumferential surface of the inner wall member  542  by bonding, screw-fastening, or the like. According to the present embodiment, the inverter housing  531  corresponds to a “housing member.” The electrical module  532  corresponds to an “electrical component.” 
     The bearing  560  is housed on the inner side of the inner peripheral wall WA 2  (boss portion  548 ). The rotation shaft  501  is supported by the bearing  560  so as to freely rotate. The bearing  560  is a hub bearing that rotatably supports the vehicle wheel  400  in a vehicle-wheel center portion. The bearing  560  is provided in a position that overlaps the rotor  510 , the stator  520 , and the inverter unit  530  in the axial direction. 
     In the rotating electric machine  500  according to the present embodiment, as a result of the magnet unit  512  being able to be made thinner in accompaniment with the orientation in the rotor  510 , and the slot-less structure and the flattened conductor structure being used in the stator  520 , the thickness dimension in the radial direction of the magnetic circuit portion can be reduced and the hollow space further towards the radially inner side than the magnetic circuit portion can be expanded. 
     As a result, arrangement of the magnetic circuit portion, the inverter unit  530 , and the bearing  560  in a state in which the magnetic circuit portion, the inverter unit  530 , and the bearing  560  are laminated in the radial direction becomes possible. The boss portion  548  serves as a bearing holding portion that holds the bearing  560  on the inner side thereof. 
     For example, the bearing  560  is a radial ball bearing. The bearing  560  includes an inner ring  561 , an outer ring  562 , and a plurality of balls  563 . The inner ring  561  forms a cylindrical shape. The outer ring  562  forms a cylindrical shape that has a larger diameter than the inner ring and is arranged on the radially outer side of the inner ring  561 . The plurality of balls  563  are arranged between the inner ring  561  and the outer ring  562 . The bearing  560  is fixed to the inverter housing  531  by the outer ring  562  being assembled to the boss formation member  543 , and the inner ring  561  is fixed to the rotation shaft  501 . These inner ring  561 , outer ring  562 , and balls  563  are all made of a metal material such as carbon steel. 
     In addition, the inner ring  561  of the bearing  560  has a cylindrical portion  561   a  that houses the rotation shaft  501  and a flange  561   b  that extends in a direction that intersects (is orthogonal to) the axial direction from one end portion in the axial direction of the cylindrical portion  561   a . The flange  561   b  is a portion that is in contact with the end plate  514  of the rotor carrier  511  from the inner side. 
     In a state in which the bearing  560  is assembled to the rotation shaft  501 , the rotor carrier  511  is held so as to be sandwiched between the flange  502  of the rotation shaft  501  and the flange  561   b  of the inner ring  561 . In this case, the flange  502  of the rotation shaft  501  and the flange  561   b  of the inner ring have a same angle of intersection in relation to the axial direction as each other (according to the present embodiment, both are right angles). The rotor carrier  511  is held so as to be sandwiched between these flanges  502  and  561   b.    
     The rotor carrier  511  is supported from the inner side by the inner ring  561  of the bearing  560 . In this configuration, an angle of the rotor carrier  511  in relation to the rotation shaft  501  can be held at an appropriate angle. Furthermore, a degree of parallelism of the magnet unit  512  in relation to the rotation shaft  501  can be favorably maintained. As a result, even when the rotor carrier  511  is expanded in the radial direction, resistance against vibration and the like can be improved. 
     Next, the electrical modules  532  that are housed in the inverter housing  531  will be described. 
     The plurality of electrical modules  532  are that in which electrical components such as the semiconductor switching element that configures the power converter and the smoothing capacitor are divided into a plurality of groups and individually modularized. The electrical modules  532  include a switch module  532 A that includes the semiconductor switching element that is a power element, and a capacitor module  532 B that includes the smoothing capacitor. 
     As shown in  FIG. 49  and  FIG. 50 , a plurality of spacers  549  that have flat surfaces for attaching the electrical modules  532  are fixed to the inner circumferential surface of the inner wall member  542 . The electrical module  532  is attached to the spacer  549 . That is, whereas the inner circumferential surface of the inner wall member  542  is a curved surface, an attachment surface of the electrical module  532  is a flat surface. Therefore, a flat surface is formed on the inner circumferential surface side of the inner wall member  542  by the spacer  549 , and the electrical module  532  is fixed to the flat surface. 
     Here, the configuration in which the spacer  549  is interposed between the inner wall member  542  and the electrical module  532  is not a requisite. The electrical module  532  can also be directly attached to the inner wall member  542  by the inner circumferential surface of the inner wall member  542  being a flat surface or the attachment surface of the electrical module  532  being a curved surface. 
     In addition, the electrical module  532  can also be fixed to the inverter housing  531  in a state in which the electrical module  532  is not in contact with the inner circumferential surface of the inner wall member  542 . For example, the electrical module  532  is fixed to the end plate  547  of the boss formation member  543 . The switch module  532 A can be fixed in a state of contact with the inner circumferential surface of the inner wall member  542 , and the capacitor module  532 B can be fixed in a state of non-contact with the inner circumferential surface of the inner wall member  542 . 
     Here, when the spacer  549  is provided on the inner circumferential surface of the inner wall member  542 , the outer peripheral wall WA 1  and the spacer  549  correspond to a “cylindrical portion.” In addition, when the spacer  549  is not used, the outer peripheral wall WA 1  corresponds to the “cylindrical portion.” 
     As described above, the cooling water passage  545  through which the cooling water that serves as a coolant flows is formed in the outer peripheral wall WA 1  of the inverter housing  531 . Each electrical module  532  is cooled by the cooling water that flows through the cooling water passage  545 . 
     Here, as the coolant, a cooling oil can also be used instead of the cooling water. The cooling water passage  545  is provided in an annular shape along the outer peripheral wall 
     WA 1 . The cooling water that flows through the cooling water passage  545  flows from an upstream side to a downstream side via each electrical module  532 . According to the present embodiment, the cooling water passage  545  is provided in an annular shape so as to overlap each electrical module  532  on the inner side and the radially outer side and surround each electrical module  532 . 
     The inner wall member  542  is provided with an inlet passage  571  through which the cooling water flows into the cooling water passage  545 , and an outlet passage  572  through which the cooling water flows out from the cooling water passage  545 . The plurality of electrical modules  532  are fixed to the inner circumferential surface of the inner wall member  542  as described above. 
     In this configuration, a space between the electrical modules that are adjacent in the circumferential direction is more expanded in a single location than other spaces. A protruding portion  573  in which a portion of the inner wall member  542  protrudes towards the radially inner side is formed in the expanded portion. In addition, the inlet passage  571  and the outlet passage  572  are provided so as to be laterally arrayed along the radial direction in the protruding portion  573 . 
     A state of the arrangement of the electrical modules  532  in the inverter housing  531  is shown in  FIG. 58 . Here,  FIG. 58  is the same longitudinal cross-sectional view as  FIG. 50 . 
     As shown in  FIG. 58 , the electrical modules  532  are arranged so as to be arrayed in the circumferential direction with an interval between the electrical modules in the circumferential direction being a first interval INT 1  or a second interval INT 2 . The second interval INT 2  is an interval that is wider than the first interval INT 1 . For example, each of the intervals INT 1  and INT 2  is a distance between center positions of two electrical modules  532  that are adjacent in the circumferential direction. 
     In this case, the interval between the electrical modules that are adjacent in the circumferential direction without the protruding portion  573  therebetween is the first interval INT 1 . The interval between the electrical modules that are adjacent in the circumferential direction with the protruding portion  573  therebetween is the second interval INT 2 . That is, the interval between the electrical modules that are adjacent in the circumferential direction is widened in a portion thereof. The protruding portion  573  is provided, for example, in a portion that is a center of the widened interval (second interval INT 2 ). 
     The intervals INT 1  and INT 2  may be a circular arc distance between the center positions of the two electrical modules  532  that are adjacent in the circumferential direction, on a same circle around the rotation shaft  51 . Alternatively, the interval between the electrical modules in the circumferential direction may be defined by angle intervals θi 1  and θi 2  with the rotation shaft  501  as a center (θi 1 &lt;θi 2 ). 
     Here, in  FIG. 58 , the electrical modules  532  that are arrayed at the first interval INTI are arranged in a state in which the electrical modules  532  are separated from each other in the circumferential direction (state of non-contact). However, instead of this configuration, the electrical modules  532  may be arranged in a state in which the electrical modules  532  are in contact with each other in the circumferential direction. 
     As shown in  FIG. 48 , a waterway port  574  in which passage end portions of the inlet passage  571  and the outlet passage  572  are formed is provided in the end plate  547  of the boss formation member  543 . A circulation path  575  that circulates the cooling water is connected to the inlet passage  571  and the outlet passage  572 . The circulation path  575  is made of a cooling water pipe. A pump  576  and a heat releasing apparatus  577  are provided on the circulation path  575 . The cooling water circulates through the cooling water passage  545  and the circulation path  575  in accompaniment with driving of the pump  576 . The pump  576  is an electric pump. For example, the heat releasing apparatus  577  is a radiator that releases heat from the cooling water into the atmosphere. 
     As shown in  FIG. 50 , the stator  520  is arranged on the outer side of the outer peripheral wall WA 1  and the electrical modules  532  are arranged on the inner side. Therefore, heat from the stator  520  is transmitted to the outer peripheral wall WA 1  from the outer side. In addition, heat from the electrical modules  532  is transmitted to the outer peripheral wall WA 1  from the inner side. 
     In this case, the stator  50  and the electrical modules  532  can be simultaneously cooled by the cooling water that flows through the cooling water passage  545 . Heat from heat generating components of the rotating electric machine  500  can be efficiently released. 
     Here, an electrical configuration of the power converter will be described with reference to  FIG. 59 . 
     As shown in  FIG. 59 , the stator winding  521  is made of the U-phase winding, the V-phase winding, and the W-phase winding. An inverter  600  is connected to the stator winding  521 . The inverter  600  is configured by a full-bridge circuit that includes a same number of upper and lower arms as the number of phases. The inverter  600  is provided with a serial-connection body that is made of an upper arm switch  601  and a lower arm switch  602 , for each phase. The switches  601  and  602  are each turned on/off by a drive circuit  603 . The winding of each phase is energized based on the on/off of the switches  601  and  602 . 
     For example, each of the switches  601  and  602  is made of a semiconductor switching element, such as a MOSFET or an IGBT. In addition, a charge-supplying capacitor  604  that supplies the switches  601  and  602  with electric charge that is required during switching is connected in parallel to the serial-connection body of the switches  601  and  602  in the upper and lower arms of each phase. 
     A control apparatus  607  includes a microcomputer that includes a CPU and various memories. The control apparatus  607  performs energization control through on/off of the switches  601  and  602  based on various types of detection information of the rotating electric machine  500 , and requests for power-running drive and power generation. 
     For example, the control apparatus  607  performs on/off control of the switches  601  and  602  by PWM control at a predetermined switching frequency (carrier frequency) or rectangular wave control. The control apparatus  607  may be an internal control apparatus that is provided inside the rotating electric machine  500  or may be an external control apparatus that is provided outside the rotating electric machine  500 . 
     Here, in the rotating electric machine  500  according to the present embodiment, the electrical time constant decreases as a result of decrease in the inductance in the stator  520 . Under such circumstances in which the electrical time constant is small, the switching frequency (carrier frequency) is preferably increased and switching speed is preferably increased. In this regard, wiring inductance decreases as a result of the charge-supplying capacitor  604  being connected in parallel to the serial-connection body of the switches  601  and  602  of each phase. Appropriate surge measures can be taken even when the switching speed is increased. 
     A high-potential-side terminal of the inverter  600  is connected to a positive electrode terminal of a direct-current power supply  605 , and a low-potential-side terminal is connected to a negative electrode terminal (ground) of the direct-current power supply  605 . In addition, a smoothing capacitor  606  is connected to the high-potential-side terminal and the low-potential-side terminal of the inverter  600 , in parallel with the direct-current power supply  605 . 
     The switch module  532 A includes the switches  601  and  602  (semiconductor switching elements), the drive circuit  603  (specifically, an electrical element that configures the drive circuit  603 ), and the charge-supplying capacitor  604  as heat generating components. In addition, the capacitor module  532 B includes the smoothing capacitor  606  as the heat generating component. A specific configuration example of the switch module  532 A is shown in  FIG. 60 . 
     As shown in  FIG. 60 , the switch module  532 A includes a module case  611  that serves as a housing case. In addition, the switch module  532 A includes the switches  601  and  602  that amount to a single phase, the drive circuit  603 , and the charge-supplying capacitor  604  that are housed inside the module case  611 . Here, the drive circuit  603  is configured as a dedicated IC or a circuit board, and is provided in the switch module  532 A. 
     For example, the module case  611  is made of an insulation material such as resin. The module case  611  is fixed to the outer peripheral wall WA 1  in a state in which a side surface thereof is in contact with the inner circumferential surface of the inner wall member  542  of the inverter unit  530 . 
     An interior of the module case  611  is filled with a molding material such as resin. Inside the module case  611 , the switches  601  and  602  and the drive circuit  603 , and the switches  601  and  602  and the capacitor  604  are each electrically connected by wiring  612 . Here, specifically, the switch module  532 A is attached to the outer peripheral wall WA 1  with the spacer  549  therebetween. However, illustration of the spacer  549  is omitted. 
     In a state in which the switch module  532 A is fixed to the outer peripheral wall WA 1 , cooling performance is higher towards a side closer to the outer peripheral wall WA 1  in the switch module  532 A, that is, towards a side closer to the cooling water passage  545 . Therefore, an order of array of the switches  601  and  602 , the drive circuit  603 , and the capacitor  604  is prescribed based on the cooling performance. 
     Specifically, when amounts of heat generation are compared, the order from the greatest is the switches  601  and  602 , the capacitor  604 , and the drive circuit  603 . Therefore, the switches  601  and  602 , the capacitor  604 , and the drive circuit  603  are arranged in this order from the side closer to the outer peripheral wall WA 1  to match the order of magnitude of the amounts of heat generation. Here, a contact surface of the switch module  532 A may be smaller than a contactable surface of the inner circumferential surface of the inner wall member  542 . 
     Here, a detailed illustration of the capacitor module  532 B is omitted. However, the capacitor module  532 B is configured such that the capacitor  606  is housed inside a module case that has a same shape and size as the switch module  532 A. In a manner similar to the switch module  532 A, the capacitor module  532 B is fixed to the outer peripheral wall WA 1  in a state in which the side surface of the module case  611  is in contact with the inner circumferential surface of the inner wall member  542  of the inverter housing  531 . 
     The switch module  532 A and the capacitor module  532 B are not necessarily required to be concentrically arrayed on the radially inner side of the outer peripheral wall WA 1  of the inverter housing  531 . For example, the switch module  532 A may be arranged further towards the radially inner side than the capacitor module  532 B is. Alternatively, the switch module  532 A and the capacitor module  532 B may be arranged in reverse of the foregoing configuration. 
     During driving of the rotating electric machine  500 , heat exchange is performed between the switch module  532 A and the capacitor module  532 B, and the cooling water passage  545  via the inner wall member  542  of the outer peripheral wall WA 1 . As a result, cooling of the switch module  532 A and the capacitor module  532 B is performed. 
     The electrical module  532  may each be configured such that the cooling water is drawn into the interior thereof, and cooling by the cooling water is performed in the module interior. Here, a water-cooled structure of the switch module  532 A will be described with reference to  FIG. 61( a )  and (b).  FIG. 61( a )  is a longitudinal cross-sectional view of a cross-sectional structure of the switch module  532 A in a direction crossing the outer peripheral wall WA 1 .  FIG. 61( b )  is a cross-sectional view taken along line  61 B- 61 B in  FIG. 61( a ) . 
     As shown in  FIG. 61( a )  and (b), in addition to including the module case  611 , the switches  601  and  602  amounting to a single phase, the drive circuit  603 , and the capacitor  604  in a manner similar to that in  FIG. 60 , the switch module  532 A includes a cooling apparatus that includes a pair of pipe portions  621  and  622 , and a cooler  623 . 
     In the cooling apparatus, the pair of pipe portions  621  and  622  are made of an inflow-side pipe portion  621  through which the cooling water flows into the cooler  623  from the cooling water passage  545  of the outer peripheral wall WA 1 , and an outflow-side pipe portion  622  from which the cooling water flows into the cooling water passage  545  from the cooler  623 . The cooler  623  is provided based on a cooling target. 
     In the cooling apparatus, a single stage or a plurality of stages of coolers  623  is used. In  FIG. 61( a )  and (b), two stages of coolers  623  are provided so as to be separated from each other in a direction away from the cooling water passage  545 , that is, the radial direction of the inverter unit  530 . The cooling water is supplied to each of the coolers  623  via the pair of pipe portions  621  and  622 . For example, the cooler  623  has an interior that is a hollow cavity. However, the interior of the cooler  623  may be provided with an inner fin. 
     In the configuration that includes the two stages of coolers  623 , each of (1) the outer peripheral wall WA 1  side of the first-stage cooler  623 , (2) between the first-stage and second-stage coolers  623 , and (3) the counter-outer peripheral wall side of the second-stage cooler  623  is a location in which an electrical component to be cooled is arranged. 
     These locations are (2), (1), (3) in order from that with the highest cooling performance. That is, the location that is sandwiched between the two coolers  623  has the highest cooling performance. In the locations that are adjacent to either one of the coolers  623 , the location closer to the outer peripheral wall WA 1  (cooling water passage  545 ) has a higher cooling performance. 
     Taking this into consideration, as shown in  FIG. 61( a )  and (b), the switches  601  and  602  are arranged (2) between the first-stage and second-stage coolers  623 , the capacitor  604  is arranged on (1) the outer peripheral wall WA 1  side of the first-stage cooler  623 , and the drive circuit  603  is arranged on (3) the counter-outer peripheral wall side of the second-stage cooler  623 . Here, although not shown, the drive circuit  603  and the capacitor  604  may be arranged in reverse. 
     In any case, the switches  601  and  602  and the drive circuit  603 , and the switches  601  and  602  and the capacitor  604  are respectively connected by the wirings  612  inside the module case  611 . In addition, because the switches  601  and  602  are positioned between the drive circuit  603  and the capacitor  604 , the wiring  612  that extends towards the drive circuit  603  from the switches  601  and  602  and the wiring  612  that extends towards the capacitor  604  from the switches  601  and  602  have a relationship in which the wirings  612  extend in directions that are opposite each other. 
     As shown in  FIG. 61( b ) , the pair of pipe portions  621  and  622  are arranged so as to be arrayed in the circumferential direction, that is, on an upstream side and a downstream side of the cooling water passage  545 . The cooling water flows from the inflow-side pipe portion  621  that is positioned on the upstream side into the cooler  623  and subsequently, the cooling water flows from the outflow-side pipe portion  622  that is positioned on the downstream side. 
     Here, to promote inflow of the cooling water into the cooling apparatus, the cooling water passage  545  may be provided with a regulating unit  624  that regulates the flow of cooling water, in a position between the inflow-side pipe portion  621  and the outflow-side pipe portion  622  when viewed in the circumferential direction. The restricting portion  624  may be a blocking portion that blocks the cooling water passage  545  or a narrowing portion that reduces a passage area of the cooling water passage  545 . 
       FIG. 62  shows another cooling structure of the switch module  532 A.  FIG. 62( a )  is a longitudinal cross-sectional view of the cross-sectional structure of the switch module  532 A in a direction crossing the outer peripheral wall WA 1 .  FIG. 62( b )  is a cross-sectional view taken along line  62 B- 62 B in  FIG. 62( a ) . 
     In  FIG. 62( a )  and (b), as a difference with the configuration in  FIG. 61( a )  and (b), described above, the arrangement of the pair of pipe portions  621  and  622  in the cooling apparatus differs. The pair of pipe portions  621  and  622  are arranged so as to be arrayed in the axial direction. 
     In addition, as shown in  FIG. 62( c ) , in the cooling water passage  545 , a passage portion that communicates with the inflow-side pipe portion  621  and a passage portion that communicates with the outflow-side pipe portion  622  are provided so as to be separated in the axial direction. These passage portions communicate through the pipe portions  621  and  622  and the coolers  623 . 
     In addition, a following configuration can also be used as the switch module  532 A. 
     In a configuration shown in  FIG. 63( a ) , compared to the configuration in  FIG. 61( a ) , the cooler  623  is changed from two stages to one stage. In this case, the location that has the highest cooling performance inside the module case  611  differs from that in  FIG. 61( a ) . The location on the outer peripheral wall WA 1  side, of both sides in the radial direction of the cooler  623  (both sides in the left/right direction in the drawing), has the highest cooling performance. 
     Next, the cooling performance decreases in the order of a location on the counter-outer peripheral wall side of the cooler  623  and a location away from the cooler  623 . Taking this into consideration, as shown in  FIG. 63( a ) , the switches  601  and  602  are arranged in the location on the outer peripheral wall WA 1  side, of both sides in the radial direction of the cooler  623  (both sides in the left/right direction in the drawing). The capacitor  604  is arranged in the location on the counter-outer peripheral wall side of the cooler  623 . The drive circuit  603  is arranged in a location away from the cooler  623 . 
     In addition, in the switch module  532 A, the configuration in which the switches  601  and  602  amounting to a single phase, the drive circuit  603 , and the capacitor  604  are housed inside the module case  611  can be modified. For example, the switches  601  and  602  amounting to a single phase and either of the drive circuit  603  and the capacitor  604  may be housed inside the module case  611 . 
     In  FIG. 63( b ) , inside the module case  611 , in addition to the pair of pipe portions  621  and  622  and the two stages of coolers  623  being provided, the switches  601  and  602  are arranged between the first-stage and second-stage coolers  623 , and the capacitor  604  or the drive circuit  603  is arranged on the outer peripheral wall WA 1  side of the first-stage cooler  623 . In addition, the switches  601  and  602  and the drive circuit  603  may be integrated into a semiconductor module, and the semiconductor module and the capacitor  604  may be housed inside the module case  611 . 
     Here, in  FIG. 63( b ) , in the switch module  532 A, a capacitor may be arranged on a side opposite the switches  601  and  602  in at least either of the coolers  623  that are arranged on both sides sandwiching the switches  601  and  602 . That is, the capacitor  604  may be arranged on only either of the outer peripheral wall WA 1  side of the first-stage cooler  623  and the counter-peripheral wall side of the second-stage cooler  623 . Alternatively, the capacitor  604  may be arranged on both sides. 
     According to the present embodiment, the cooling water is drawn into the module interior from the cooling water passage  545  for only the switch module  532 A, of the switch module  532 A and the capacitor module  532 B. However, the configuration may be modified. The cooling water may be drawn into both modules  532 A and  532 B from the cooling water passage  545 . 
     In addition, the cooling water may come into direct contact with the outer surface of each electrical module  532  and may cool each electrical module  532 . For example, as shown in  FIG. 64 , the cooling water is placed in contact with the outer surface of the electrical module  532  by the electrical module  532  being embedded in the outer peripheral wall WA 1 . 
     In this case, a configuration in which a portion of the electrical module  532  is immersed inside the cooling water passage  545 , or a configuration in which the cooling water passage  545  is further expanded in the radial direction than that in the configuration in  FIG. 58  and the like, and the overall electrical module  532  is immersed inside the cooling water passage  545  can be considered. When the electrical module  532  is immersed inside the cooling water passage  545 , if a fin is provided in the immersed module case  611  (an immersed portion of the module case  611 ), cooling performance can be further improved. 
     In addition, the electrical modules  532  include the switch module  532 A and the capacitor module  532 B. When both are compared, there is a difference in the amount of heat generation. Taking this into consideration, the arrangement of the electrical modules  532  in the inverter housing  531  can be modified as well. 
     For example, as shown in  FIG. 65 , a plurality of switch modules  532 A are arrayed in the circumferential direction without being dispersed and are arranged on the upstream side of the cooling water passage  545 , that is, the side close to the inlet passage  571 . In this case, the cooling water that flows in from the inlet passage  571  is first used to cool the three switch modules  532 A and subsequently used to cool the capacitor modules  532 B. 
     Here, in  FIG. 65 , the pair of pipe portions  621  and  622  are arranged so as to be arrayed in the axial direction as in  FIG. 62( a )  and (b), above. However, the arrangement is not limited thereto. The pair of pipe portions  621  and  622  may be arranged so as to be arrayed in the circumferential direction as in  FIG. 61( a )  and (b), above. 
     Next, a configuration related to the electrical connection of the electrical modules  532  and the bus bar module  533  will be described.  FIG. 66  is a cross-sectional view taken along line  66 - 66  in  FIG. 49 .  FIG. 67  is a cross-sectional view taken along line  67 - 67  in  FIG. 49 .  FIG. 68  is a perspective view showing a bus bar module  533  alone. Here, the configuration related to the electrical connection between the electrical modules  532  and the bus bar module  533  will be described with reference to these drawings. 
     As shown in  FIG. 66 , in the inverter housing  531 , three switch modules  532 A are arranged so as to be arrayed in the circumferential direction in a position adjacent in the circumferential direction to the protruding portion  573  that is provided in the inner wall member  542  (that is, the protruding portion  573  in which the inlet passage  571  and the outlet passage  572  that communicate with the cooling water passage  545  are provided), and six capacitor modules  532 B are arranged so as to be arrayed in the circumferential direction, further adjacent thereto. 
     As an overview of the foregoing, in the inverter housing  531 , the inner side of the outer peripheral wall WA 1  is evenly divided into ten areas (that is, the number of modules+1) in the circumferential direction. Of the ten areas, the electrical modules  532  are arranged one each in the nine areas. The protruding portion  573  is provided in the remaining one area. The three switch modules  532 A are a U-phase module, a V-phase module, and a W-phase module. 
     As shown in  FIG. 66 , and above-described  FIG. 56 ,  FIG. 57 , and the like, each electrical module  532  (switch module  532 A and capacitor module  532 B) includes a plurality of module terminals  615  that extend from the module case  611 . The module terminal  615  is a module input/output terminal that enables electrical input and output to be performed in the electrical module  532 . The module terminal  615  is provided so as to be oriented to extend in the axial direction. More specifically, the module terminal  615  is provided so as to extend from the module case  611  towards a rear side (vehicle outer side) of the rotor carrier  511  (see  FIG. 51 ). 
     Each module terminal  615  of the electrical module  532  is connected to the bus bar module  533 . The number of module terminals  615  differs between the switch module  532 A and the capacitor module  532 B. Four module terminals  615  are provided in the switch module  532 A and two module terminals  615  are provided in the capacitor module  532 B. 
     In addition, as shown in  FIG. 68 , the bus bar module  533  includes an annular portion  631  that forms a circular annular shape, three external connection terminals  632  that extend from the annular portion  631  and enable connection to an external apparatus, such as a power supply apparatus or an ECU, and a winding connection terminal  633  that is connected to a winding end portion of each phase in the stator winding  521 . The bus bar module  533  corresponds to a “terminal module.” 
     The annular portion  631  is arranged in a position that is on the radially inner side of the outer peripheral wall WA 1  in the inverter housing  531  and on one side in the axial direction of the electrical modules  532 . 
     For example, the annular portion  631  has a circular annular main body portion that is formed by an insulation member that is made of resin or the like, and a plurality of bus bars that are embedded inside main body portion. The plurality of bus bars are connected to the module terminals  615  of each electrical module  532 , each external connection terminal  632 , and each phase winding of the stator winding  521 . Details thereof are described hereafter. 
     The external connection terminal  632  is made of a high-potential-side power terminal  632 A and a low-potential-side power terminal  632 B that are connected to the power supply apparatus, and a single signal terminal  632 C that is connected to an external ECU. These external connection terminals  632  ( 632 A to  632 C) are provided so as to be arrayed in a single row in the circumferential direction and extend in the axial direction on the radially inner side of the annular portion  631 . 
     As shown in  FIG. 51 , in a state in which the bus bar module  533  is assembled to the inverter housing  531  together with the electrical modules  532 , one end of the external connection terminal  632  protrudes from the end plate  547  of the boss formation member  543 . 
     Specifically, as shown in  FIG. 56  and  FIG. 57 , an insertion hole  547   a  is provided in the end plate  547  of the boss formation member  543 . A circular cylindrical grommet  635  is attached to the insertion hole  547   a , and the external connection terminal  632  is provided so as to be inserted through the grommet  635 . The grommet  635  also functions as a sealed connector. 
     The winding connection terminal  633  is a terminal that is connected to the winding end portion of each phase of the stator winding  521  and is provided so as to extend from the annular portion  631  towards the radially outer side. The winding connection terminal  633  includes a winding connection terminal  633 U that is connected to the end portion of the U-phase winding of the stator winding  521 , a winding connection terminal  633 V that is connected to the end portion of the V-phase winding, and a winding connection terminal  633 W that is connected to the end portion of the W-phase winding. 
     A current sensor  634  that detects a current (U-phase current, V-phase current, and W-phase current) that flows to each of these winding connection terminals  633  and each phase winding may be provided (see  FIG. 70 ). 
     Here, the current sensor  634  may be arranged outside the electrical module  532  in the periphery of each winding connection terminal  633 . Alternatively, the current sensor  634  may be arranged inside the electrical module  532 . 
     Here, the connection between the electrical modules  532  and the bus bar module  533  will be described in detail with reference to  FIG. 69  and  FIG. 70 . 
       FIG. 69  shows the electrical modules  532  expanded in plan view, and schematically shows a state of electrical connection between the electrical modules  532  and the bus bar module  533 .  FIG. 70  is a diagram that schematically shows the connection between the electrical modules  532  and the bus bar modules  533  in a state in which the electrical modules  532  are arranged in a circular annular shape. Here, in  FIG. 69 , a path for power transmission is indicated by a solid line and a path for signal transmission is indicated by a single-dot chain line. Only the path for power transmission is shown in  FIG. 70 . 
     The bus bar module  533  includes a first bus bar  41 , a second bus bar  42 , and a third bus bar  43  as bus bars for power transmission. Of the bus bars, the first bus bar  641  is connected to the power terminal  632 A on the high potential side and the second bus bar  642  is connected to the power terminal  632 B on the low potential side. In addition, three third bus bars  643  are respectively connected to the U-phase winding connection terminal  633 U, the V-phase winding connection terminal  633 V, and the W-phase winding connection terminal  633 W. 
     Moreover, the winding connection terminals  633  and the third bus bars  643  are sections that tend to generate heat as a result of operation of the rotating electric machine  10 . Therefore, a terminal block (not shown) may be interposed between the winding connection terminals  633  and the third bus bars  643 . 
     In addition, the terminal block may be placed in contact with the inverter housing  531  that includes the cooling water passage  545 . Alternatively, as a result of the winding connection terminals  633  and the third bus bars  643  being bent into a crank-like shape, the winding connection terminals  633  and the third bus bards  643  may be placed in contact with the inverter housing  531  that includes the cooling water passage  545 . 
     As a result of a configuration such as this, the heat that is generated in the winding connection terminals  633  and the third bus bars  643  can be released to the cooling water inside the cooling water passage  545 . 
     Here, in  FIG. 70 , the first bus bar  641  and the second bus bar  642  are shown as bus bars that form a circular annular shape. However, these bus bars  641  and  642  are not necessarily required to be connected in a circular annular shape and may form an approximately C-like shape in which a portion in the circumferential direction is discontinuous. 
     In addition, because the winding connection terminals  633 U,  633 V, and  633 W are merely required to be individually connected to the switching modules  532 A that corresponds to the respective phases, the winding connection terminals  633 U,  633 V, and  633 W may be directly connected to the switch modules  532 A (in actuality, the module terminals  615 ) without the bus bar modules  533  therebetween. 
     Meanwhile, each switch module  532 A includes four module terminals  615  that are made of a positive-electrode-side terminal, a negative-electrode-side terminal, a winding terminal, and a signal terminal. Of the module terminals  615 , the positive-electrode-side terminal is connected to the first bus bar  641 , the negative-electrode-side terminal is connected to the second bus bar  642 , and the winding terminal is connected to the third bus bar  643 . 
     In addition, the bus bar module  533  includes a fourth bus bar  644  that serves as a bus bar for the signal transmission system. The signal terminal of each switch module  532 A is connected to the fourth bus bar  644 , and the fourth bus bar  644  is connected to the signal terminal  632 C. 
     According to the present embodiment, a control signal for the each switch module  532 A is inputted from the external ECU via the signal terminal  632 C. That is, the switches  601  and  602  in the switch module  532 A are turned on/off by the control signal that is inputted via the signal terminal  632 C. 
     Therefore, the switch module  632 A is configured to be connected to the signal terminal  632 C without going through a control apparatus that is provided inside the rotating electric machine, midway. However, this configuration may be modified. A control apparatus may be provided inside the rotating electric machine and a control signal from the control apparatus may be inputted to the switch module  532 A. This configuration is shown in  FIG. 71 . 
     The configuration in  FIG. 71  includes a control board  651  on which a control apparatus  652  is mounted. The control apparatus  652  is connected to each switch module  532 A. In addition, the signal terminal  632 C is connected to the control apparatus  652 . In this case, for example, the control apparatus  652  receives input of a command signal that is related to power-running or power generation from the external ECU that is a higher-order control apparatus, and turns on/off the switches  601  and  602  of each switch module  532 A as appropriate, based on the command signal. 
     In the inverter unit  530 , the control board  651  may be arranged further towards the vehicle outer side (rear side of the rotor carrier  511 ) than the bus bar module  533 . Alternatively, the control board  651  may be arranged between the electrical modules  532  and the end plate  547  of the boss formation member  543 . The control board  651  may be arranged such that at least a portion thereof overlaps the electrical modules  532  in the axial direction. 
     In addition, the capacitor module  532 B includes two module terminals  615  that are made of a positive-electrode-side terminal and a negative-electrode-side terminal. The positive-electrode-side terminal is connected to the first bus bar  641  and the negative-electrode-side terminal is connected to the second bus bar  642 . 
     As shown in  FIG. 49  and  FIG. 50 , inside the inverter housing  531 , the protruding portion  573  that includes the inlet passage  571  and the outlet passage  572  for the cooling water is provided inside the inverter housing  531  in a position that is arrayed with the electrical modules  532  in the circumferential direction. In addition, the external connection terminal  632  is provided so as to be adjacent in the radial direction to the protruding portion  573 . In other words, the protruding portion  573  and the external connection terminal  632  are provided in a same angular position in the circumferential direction. 
     According to the present embodiment, the external connection terminal  632  is provided in a position on the radially inner side of the protruding portion  573 . In addition, when viewed from the vehicle inner side of the inverter housing  531 , the waterway port  574  and the external connection terminal  632  are provided so as to be arrayed in the radial direction on the end plate  547  of the boss formation member  543  (see  FIG. 48 ). 
     In this case, as a result of the protruding portion  573  and the external connection terminal  632  being arranged so as to be arrayed in the circumferential direction together with the plurality of electrical modules  532 , size reduction as the inverter unit  530 , and further, size reduction as the rotating electric machine  500  can be achieved. 
     With reference to  FIG. 45  and  FIG. 47  that show the structure of the vehicle wheel  400 , the cooling pipe H 2  is connected to the waterway port  574  and the electrical wiring H 1  is connected to the external connection terminal  632 . In this state, the electrical wiring H 1  and the cooling pipe H 2  are housed in the housing duct  440 . 
     Here, in the above-described configuration, three switch modules  532 A are arranged in an array in the circumferential direction adjacent to the external connection terminal  632  inside the inverter housing  631 , and the six capacitor modules  532 B are arranged in an array in the circumferential direction further adjacent thereto. However, the configuration may be modified. 
     For example, the three switch modules  532 A may be arranged so as to be arrayed in a position farthest from the external connection terminal  632 , that is, a position on a side opposite the external connection terminal  632  with the rotation shaft  501  therebetween. In addition, the switch modules  532 A can be distributively arranged such that the capacitor modules  532 B are arranged on both sides of the switch modules  532 A. 
     As a result of the configuration in which the switch modules  532 A are arranged in the position farthest from the external connection terminal  632 , that is, in the position on the side opposite the external connection terminal  632  with the rotation shaft  501  therebetween, malfunction attributed to mutual inductance between the external connection terminal  632  and the switch modules  532 A, and the like can be suppressed. 
     Next, a configuration related to a resolver  660  that is provided as a rotation angle sensor will be described. 
     As shown in  FIG. 49  to  FIG. 51 , the resolver  660  that detects the electrical angle  0  of the rotating electric machine  500  is provided in the inverter housing  531 . The resolver  660  is an electromagnetic-induction-type sensor. The resolver  660  includes a resolver rotor  661  that is fixed to the rotation shaft  501  and a resolver stator  662  that is arranged in an opposing manner on the radially outer side of the resolver  661 . 
     The resolver rotor  661  has a circular-disk ring shape and is provided coaxially with the rotation shaft  501  in a state in which the rotation shaft  501  is inserted into the resolver rotor  661 . The resolver stator  662  includes a stator core  663  that has a circular annular shape and a stator coil  664  that is wound around a plurality of teeth that are formed in the stator core  663 . An excitation coil of a single phase and output coils of two phases are included in the stator coil  664 . 
     The excitation coil of the stator coil  664  is excited by a sine-wave excitation signal. A magnetic flux that is generated in the excitation coil by the excitation signal interlinks the pair of output coils. At this time, a relative arrangement relationship between the excitation coil and the pair of output coils periodically changes based on a rotation angle of the resolver rotor  661  (that is, a rotation angle of the rotation shaft  501 ). Therefore, the number of magnetic fluxes (number of flux interlinkage) that interlink the pair of output coils periodically changes. 
     According to the present embodiment, the pair of output coils and the excitation coil are arranged such that phases of voltages that are respectively generated in the pair of output coils are shifted from each other by π/ 2 . As a result, respective output voltages of the pair of output coils are modulated waves obtained by the excitation signal being respectively modulated by modulation waves sinθ and cosθ. More specifically, when the excitation signal is sinΩt, the modulation waves are respectively sinθΩ×sinΩt and cosθ×sinΩt. 
     The resolver  660  includes a resolver digital converter. The resolver digital converter calculates the electrical angle θ by detection based on the generated modulated waves and the excitation signal. 
     For example, the resolver  660  is connected to the signal terminal  632 C and the calculation result of the resolver digital converter is outputted to an external apparatus via the signal terminal  632 C. In addition, when the control apparatus is provided inside the rotating electric machine  500 , the calculation result of the resolver digital converter is inputted to the control apparatus. 
     Here, an assembly structure of the resolver  660  in the inverter housing  531  will be described. 
     As shown in  FIG. 49  and  FIG. 51 , the boss portion  548  of the boss formation member  543  that configures the inverter housing  531  has a hollow cylindrical shape. A protruding portion  548   a  that extends in a direction that is orthogonal to the axial direction is formed on an inner circumferential side of the boss portion  548 . 
     In addition, the resolver stator  662  is fixed by a screw or the like in a state in which the resolver stator  662  is in contact with the protruding portion  548   a  in the axial direction. Inside the boss portion  548 , the bearing  560  is provided on one side in the axial direction with the protruding portion  548   a  therebetween. In addition, the resolver  660  is coaxially provided on the other side. 
     Furthermore, in the hollow portion of the boss portion  548 , the protruding portion  548   a  is provided on one side of the resolver  660  in the axial direction and a circular-disk ring-shaped housing cover  666  that closes a housing space of the resolver  660  is attached on the other side. 
     The housing cover  666  is made of a conductive material such as a CFRP. A hole  666   a  into which the rotation shaft  501  is inserted is formed in a center portion of the housing cover  666 . A sealing member  667  that seals a space between the housing cover  666  and the outer circumferential surface of the rotation shaft  501  is provided in the hole  666   a . A resolver housing space is sealed by the sealing material  667 . For example, the sealing material  667  may be a sliding seal that is made of a resin material. 
     The space in which the resolver  660  is housed is a space that is surrounded by the boss portion  548  that has a circular annular shape in the boss formation member  543 , and sandwiched between the bearing  560  and the housing cover  666  in the axial direction. The surrounding of the resolver  660  is surrounded by a conductive material. As a result, the effects of electromagnetic noise on the resolver  660  can be suppressed. 
     In addition, as described above, the inverter housing  531  includes the outer peripheral wall WA 1  and the inner peripheral wall WA 2  that form two layers (see  FIG. 57 ). The stator  520  is arranged on the outer side of the peripheral walls that form the two layers (the outer side of the outer peripheral wall WA 1 ), the electrical modules  532  are arranged between the two layers of peripheral walls (between WA 1  and WA 2 ), and the resolver  660  is arranged on the inner side of the two layers of peripheral walls (the inner side of the inner peripheral wall WA 2 ). The inverter housing  531  is a conductive member. 
     Therefore, the stator  520  and the resolver  660  are arranged so as to be separated by a conductive partition wall (in particular, two layers of conductive partition walls according to the present embodiment). Occurrence of mutual magnetic interference on the stator  520  side (magnetic circuit side) and the resolver  660  can be suitably suppressed. 
     Next, a rotor cover  670  that is provided on a side of an open end portion of the rotor carrier  511  will be described. 
     As shown in  FIG. 49  and  FIG. 51 , one side of the rotor carrier  511  in the axial direction is open. An approximately circular-disk ring-shaped rotor cover  670  is attached to the open end portion. The rotor cover  670  may be fixed to the rotor carrier  511  by an arbitrary joining method such as welding, bonding, or screw fastening. The rotor cover  670  preferably has a portion in which a dimension is set so as to be smaller than an inner circumference of the rotor carrier  511  such that movement in the axial direction of the magnet unit  512  can be suppressed. 
     An outer diameter dimension of the rotor cover  670  coincides with an outer diameter dimension of the rotor carrier  511  and an inner diameter dimension is a dimension that is slightly larger than an outer diameter dimension of the inverter housing  531 . Here, the outer diameter dimension of the inverter housing  531  and the inner diameter dimension of the stator  520  are the same. 
     As described above, the stator  520  is fixed on the radially outer side of the inverter housing  531 . In a joining portion in which the stator  520  and the inverter housing  531  are joined to each other, the inverter housing  531  protrudes in the axial direction in relation to the stator  520 . In addition, the rotor cover  670  is attached so as to surround the protruding portion of the inverter housing  531 . 
     In this case, a sealing member  671  that seals a space between an end surface on the inner circumferential side of the rotor cover  670  and an outer circumferential surface of the inverter housing  531  is provided therebetween. A housing space of the magnet unit  512  and the stator  520  is sealed by the sealing member  671 . For example, the sealing member  671  may be a sliding seal that is made of a resin material. 
     According to the present embodiment described in detail above, the following excellent effects are achieved. 
     In the rotating electric machine  500 , the outer peripheral wall WA 1  of the inverter housing  531  is arranged on the radially inner side of the magnetic circuit portion that is made of the magnet unit  512  and the stator winding  521 . The cooling water passage  545  is formed in the outer peripheral wall WA 1 . In addition, the plurality of electrical modules  532  are arranged on the radially inner side of the outer peripheral wall WA 1  in the circumferential direction along the outer peripheral wall WA 1 . 
     As a result, the magnetic circuit portion, the cooling water passage  545 , and the power converter can be arranged so as to be laminated in the radial direction of the rotating electric machine  500 . Efficient component arrangement can be achieved while reduction in dimension in the axial direction is achieved. In addition, efficient cooling can be performed in the plurality of electrical modules  532  that configure the power converter. As a result, in the rotating electric machine  500 , high efficiency and size reduction can be implemented. 
     The electrical modules  532  (switch module  532 A and capacitor module  532 B) that have heat generating components such as the semiconductor switching element and the capacitor are provided so as to be in contact with the inner circumferential surface of the outer peripheral wall WA 1 . As a result, the heat from the electrical module  532  is transmitted to the outer peripheral wall WA 1  and the electrical module  532  is suitably cooled as a result of heat exchange in the outer peripheral wall WA 1 . 
     In the switch module  532 A, the coolers  623  are arranged on both sides sandwiching the switches  601  and  602 , and the capacitor  604  is arranged on a side opposite the switches  601  and  602  in at least either of the coolers  623  on both sides of the switches  601  and  602 . As a result, cooling performance regarding the switches  601  and  602  can be improved. In addition, cooling performance regarding the capacitor  604  can be improved. 
     In the switch module  532 A, the coolers  623  are arranged on both sides sandwiching the switches  601  and  602 , the drive circuit  603  is arranged on a side opposite the switches  601  and  602  in at least either of the coolers  623  on both sides of the switches  601  and  602 , and the capacitor  604  is arranged on the side opposite the switches  601  and  602  in the other cooler  623 . As a result, the cooling performance regarding the switches  601  and  602  can be improved. In addition, cooling performance regarding the drive circuit  603  and the capacitor  604  can also be improved. 
     For example, in the switch module  532 A, the cooling water is supplied from the cooling water passage  545  into the module interior, and the semiconductor switching elements and the like are cooled by the cooling water. In this case, the switch module  532 A is cooled by heat exchange by the cooling water in the module interior in addition to heat exchange by the cooling water in the outer peripheral wall WA 1 . As a result, the cooling effect of the switch module  532 A can be improved. 
     In the cooling system in which the cooling water is supplied into the cooling water passage  545  from the external circulation path  575 , the switch module  532 A is arranged on an upstream side close to the inlet passage  571  of the cooling water passage  545  and the capacitor module  532 B is arranged further towards the downstream side than the switch module  532 A is. In this case, under an assumption that the cooling water that flows through the cooling water passage  545  is at a lower temperature towards the upstream side, a configuration that preferentially cools the switch module  532 A can be implemented. 
     A portion of the gaps between electrical modules that are adjacent to each other in the circumferential direction is widened, and the protruding portion  573  that includes the inlet passage  571  and the outlet passage  572  is provided in the portion that is the widened gap (second interval INT 2 ). As a result, the inlet passage  571  and the outlet passage  572  of the cooling water passage  545  can be suitably formed in a portion that is on the radially inner side of the outer peripheral wall WA 1 . 
     That is, a flow amount of coolant is required to be ensured to improve cooling performance. Therefore, increasing opening areas of the inlet passage  571  and the outlet passage  572  can be considered. In this regard, as a result of a portion of the gaps between the electrical modules being widened and the protruding portion  573  being provided as described above, the inlet passage  571  and the outlet passage  572  that are of the desired size can be suitably formed. 
     The external connection terminal  632  of the bus bar module  533  is arranged in a position that is arrayed with the protruding portion  573  in the radial direction on the radially inner side of the outer peripheral wall WA 1 . That is, the external connection terminal  632  is arranged together with the protruding portion  573  in the portion in which the gap between electrical modules that are adjacent to each other in the circumferential direction is widened (the portion corresponding to the second interval INT 2 ). As a result, the external connection terminal  632  can be suitably arranged while interference with the electrical modules  532  is avoided. 
     In the outer-rotor-type rotating electric machine  500 , the stator  520  is fixed on the radially outer side of the outer peripheral wall WA 1  and the plurality of electrical modules  532  are arranged on the radially inner side thereof. 
     As a result, the heat from the stator  520  is transmitted to the outer peripheral wall WA 1  from the radially outer side thereof and the heat from the electrical modules  532  is transmitted from the radially inner side. In this case, the stator  520  and the electrical modules  532  can be simultaneously cooled by the cooling water that flows through the cooling water passage  545 . Heat from the heat generating components of the rotating electric machine  500  can be efficiently released. 
     The electrical module  532  on the radially inner side and the stator winding  521  on the radially outer side with the outer peripheral wall WA 1  therebetween are electrically connected by the winding connection terminal  633  of the bus bar module  533 . In addition, in this case, the winding connection terminal  633  is provided in a position away from the cooling water passage  545  in the axial direction. 
     As a result, even when the cooling water passage  545  is formed in an annular shape in the outer peripheral wall WA 1 , that is, a configuration in which the inner side and the outer side of the outer peripheral wall WA 1  is divided by the cooling water passage  545 , the electrical module  532  and the stator winding  521  can be suitably connected. 
     In the rotating electric machine  500  according to the present embodiment, as a result of the teeth (core) between the conductors  523  that are arrayed in the circumferential direction in the stator  520  being made smaller or eliminated, torque restrictions attributed to magnetic saturation that occurs between the conductors  523  are suppressed and torque decrease is suppressed by the conductor  523  being a thin, flat type. 
     In this case, even if outer diameter dimensions of the rotating electric machine  500  are the same, as a result of the stator  520  being made thinner, the area on the radially inner side of the magnetic circuit portion can be expanded. The outer peripheral wall WA 1  that includes the cooling water passage  454  and the plurality of electrical modules  532  that are provided on the radially inner side of the outer peripheral wall WA 1  can be suitably arranged using the inner area. 
     In the rotating electric machine  500  according to the present embodiment, the magnet magnetic flux on the d-axis is reinforced by the magnet magnetic flux being concentrated on the d-axis side in the magnet unit  512 . Torque enhancement that accompanies the reinforcement of the magnetic flux can be achieved. 
     In this case, in accompaniment with a thickness dimension in the radial direction of the magnet unit  512  being able to be made smaller (thinner), the area on the radially inner side of the magnetic circuit portion can be expanded. The outer peripheral wall WA 1  that includes the cooling water passage  454  and the plurality of electrical modules  532  that are provided on the radially inner side of the outer peripheral wall WA 1  can be suitably arranged using the inner area. 
     In addition, the bearing  560  and the resolver  660  can also be similarly suitably arranged in the radial direction, in addition to the magnetic circuit portion, the outer peripheral wall WA 1 , and the plurality of electrical modules  532 . 
     The vehicle wheel  400  in which the rotating electric machine  500  is used as the in-wheel motor is mounted in the vehicle body by the base plate  405  that is fixed to the inverter housing  531  and a mounting mechanism such as a suspension apparatus. Here, because size reduction is implemented in the rotating electric machine  500 , space saving can be achieved even when assembly to a vehicle body is assumed. Therefore, a configuration that is advantageous in terms of expansion of an installation area for a power supply apparatus, such as a battery, or expansion of a vehicle cabin space in the vehicle can be implemented. 
     Modifications related to the in-wheel motor will be described below. 
     (Modification 1 of the In-Wheel Motor) 
     In the rotating electric machine  500 , the electrical module  532  and the bus bar module  533  are arranged on the radially inner side of the outer peripheral wall WA 1  of the inverter unit  530 . In addition, the electrical module  532  and the bus bar module  533 , and the stator  520  are respectively arranged on the inner side and the radially outer side with the outer peripheral wall WA 1  therebetween. 
     In this configuration, the position of the bus bar module  533  in relation to the electrical module  532  can be arbitrarily set. In addition, in a case in which the phase windings of the stator winding  521  and the bus bar module  533  are connected so as to cross the outer peripheral wall WA 1  in the radial direction, a position in which a winding connection line (such as the winding connection terminal  633 ) used for the connection is guided can be arbitrarily set. 
     That is, as the position of the bus bar module  533  in relation to the electrical module  532 , (α 1 ) a configuration in which the bus bar module  533  is further towards the vehicle outer side than the electrical module  532  in the axial direction, that is, towards the rear side on the rotor carrier  511  side, and (α 2 ) a configuration in which the bus bar module  533  is further towards the vehicle inner side than the electrical module  533  in the axial direction, that is, towards the front side on the rotor carrier  511  side, can be considered. 
     In addition, as the position in which the winding connection line is guided, (β 1 ) a configuration in which the winding connection line is guided on the vehicle outer side in the axial direction, that is, on the rear side on the rotor carrier  511  side, and (β 2 ) a configuration in which the winding connection line is guided on the vehicle inner side in the axial direction, that is, on the front side on the rotor carrier  511  side, can be considered. 
     Hereafter, four configuration examples related to an arrangement of the electrical modules  532 , the bus bar module  533 , and the winding connection line will be described with reference to  FIG. 72( a ) to ( d ) . 
       FIG. 72( a ) to ( d )  are longitudinal cross-sectional views showing the configuration of the rotating electric machine  500  in a simplified manner. In  FIG. 72( a ) to ( d ) , configurations that are already described are given the same reference numbers. A winding connection line  637  is electrical wiring that connects the phase windings of the stator winding  521  and the bus bar module  533 . For example, the above-described winding connection terminal  633  corresponds to the winding connection line  637 . 
     In the configuration in  FIG. 72( a ) , the above-described (α 1 ) is used as the position of the bus bar module  533  in relation to the electrical module  532 , and the above-described (β 1 ) is used as the position for guiding the winding connection line  637 . That is, the electrical module  532  and the bus bar module  533 , and the stator winding  521  and the bus bar module  533  are both connected on the vehicle outer side (rear side of the rotor carrier  511 ). Here, this configuration corresponds to the configuration shown in  FIG. 49 . 
     As a result of the present configuration, the cooling water passage  545  can be provided in the outer peripheral wall WA 1  without concern regarding interference with the winding connection line  637 . In addition, the winding connection line  637  that connects the stator winding  521  and the bus bar module  533  can be easily implemented. 
     In  FIG. 72( b ) , the above-described (α 1 ) is used as the position of the bus bar module  533  in relation to the electrical module  532 , and the above-described (β 2 ) is used as the position for guiding the winding connection line  637 . That is, the electrical module  532  and the bus bar module  533  are connected on the vehicle outer side (rear side of the rotor carrier  511 ), and the stator winding  521  and the bus bar module  533  are connected on the vehicle inner side (front side of the rotor carrier  511 ). 
     As a result of the present configuration, the cooling water passage  545  can be provided in the outer peripheral wall WA 1  without concern regarding interference with the winding connection line  637 . 
     In  FIG. 72( c ) , the above-described (α 2 ) is used as the position of the bus bar module  533  in relation to the electrical module  532 , and the above-described (β 1 ) is used as the position for guiding the winding connection line  637 . That is, the electrical module  532  and the bus bar module  533  are connected on the vehicle inner side (front side of the rotor carrier  511 ), and the stator winding  521  and the bus bar module  533  are connected on the vehicle outer side (rear side of the rotor carrier  511 ). 
     In  FIG. 72( d ) , the above-described (α 2 ) is used as the position of the bus bar module  533  in relation to the electrical module  532 , and the above-described (β 2 ) is used as the position for guiding the winding connection line  637 . That is, the electrical module  532  and the bus bar module  533 , and the stator winding  521  and the bus bar module  533  are both connected on the vehicle inner side (front side of the rotor carrier  511 ). 
     According to the configurations in  FIG. 72( c )  and  FIG. 72( d ) , because the bus bar module  533  is arranged on the vehicle inner side (front side of the rotor carrier  511 ), if an electrical component such as a fan motor is added, wiring thereof is thought to be facilitated. In addition, the bus bar module  533  can be brought closer to the resolver  660  that is arranged further towards the vehicle inner side than the bearing is. Wiring of the resolver  660  is thought to be facilitated. 
     (Modification 2 of the In-Wheel Motor) 
     Modifications of an attachment structure of the resolver rotor  661  will be described below. That is, the rotation shaft  501 , the rotor carrier  511 , and the inner ring  561  of the bearing  560  are a rotating body that integrally rotates. Modifications of an attachment structure of the resolver rotor  661  in relation to the rotation body will be described below. 
       FIG. 73( a ) to ( c )  are configuration diagrams of examples of the attachment structure of the resolver rotor  611  in relation to the above-described rotation body. In all of the configurations, the resolver  660  is surrounded by the rotor carrier  511 , the inverter housing  531 , and the like, and is provided in a sealed space that is protected from exposure to moisture, dirt, and the like from outside. In  FIG. 73( a )  among  FIG. 73( a ) to ( c ) , the bearing  560  has the same configuration as that in  FIG. 49 . 
     In addition, in  FIG. 73( b )  and  FIG. 73( c ) , the bearing  560  has a configuration differing from that in  FIG. 49 , and is arranged in a position away from the end plate  514  of the rotor carrier  511 . Two locations are shown as examples of an attachment location of the resolver  611  in the drawings. Here, the resolver stator  662  is not shown. However, the boss portion  548  of the boss formation member  543  may be extended to the outer circumferential side of the resolver rotor  661  or the vicinity thereof, and the resolver stator  662  may be fixed to the boss portion  548 . 
     In the configuration in  FIG. 73( a ) , the resolver rotor  661  is attached to the inner ring  561  of the bearing  560 . Specifically, the resolver rotor  661  is provided on the end surface in the axial direction of the flange  561   b  of the inner ring  561 . Alternatively, the resolver rotor  661  is provided on the end surface in the axial direction of the cylindrical portion  561   a  of the inner ring  561 . 
     In  FIG. 73( b ) , the resolver rotor  611  is attached to the rotor carrier  511 . Specifically, the resolver rotor  661  is provided on the inner surface of the end plate  514  of the rotor carrier  511 . Alternatively, the rotor carrier  511  includes a cylindrical portion  515  that extends from an inner circumferential edge portion of the end plate  514  along the rotation shaft  501 . In this configuration, the resolver rotor  661  is provided on an outer circumferential surface of the cylindrical portion  515  of the rotor carrier  511 . In the latter case, the resolver rotor  661  is arranged between the end plate  514  of the rotor carrier  511  and the bearing  560 . 
     In  FIG. 73( c ) , the resolver rotor  661  is attached to the rotation shaft  501 . Specifically, the resolver rotor  661  is provided between the end plate  514  of the rotor carrier  511  and the bearing  560  in the rotation shaft  501 . Alternatively, the resolver rotor  661  is arranged in the rotation shaft  501  on the side opposite the rotor carrier  511  with the bearing  560  therebetween. 
     (Modification 3 of the In-Wheel Motor) 
     Modifications of the inverter housing  531  and the rotor cover  670  will be described with reference to  FIG. 74 .  FIG. 74( a )  and  FIG. 74( b )  are longitudinal cross-sectional views showing the configuration of the rotating electric machine  500  in a simplified manner. In  FIG. 74( a )  and  FIG. 74( b ) , configurations that are already described are given the same reference numbers. Here, a configuration shown in  FIG. 74(a)  essentially corresponds to the configuration described with reference to  FIG. 49  and the like. A configuration shown in  FIG. 74( b )  corresponds to a configuration in which a portion of the configuration in  FIG. 74( a )  is modified. 
     As shown in  FIG. 74( a ) , the rotor cover  670  that is fixed to the open end portion of the rotor carrier  511  is provided so as to surround the outer peripheral wall WA 1  of the inverter housing  531 . That is, the end surface on the inner diameter side of the rotor cover  670  opposes the outer circumferential surface of the outer peripheral wall WA 1 , and the sealing member  671  is provided therebetween. 
     In addition, the housing cover  666  is attached in the hollow portion of the boss portion  548  of the inverter housing  531 , and the sealing member  667  is provided between the housing cover  666  and the rotation shaft  501 . The external connection terminal  632  that configures the bus bar module  533  passes through the inverter housing  531  and extends toward the vehicle inner side (lower side in the drawings). 
     In addition, in the inverter housing  531 , the inlet passage  571  and the outlet passage  572  that communicate with the cooling water passage  545  are formed, and the waterway port  574  that includes the passage end portions of the inlet passage  571  and the outlet passage  572  is formed. 
     In contrast, as shown in  FIG. 74( b ) , an annular protruding portion  81  that extends towards the protruding side (vehicle inner side) of the rotation shaft  501  is formed in the inverter housing  531  (specifically, the boss formation member  543 ). The rotor cover  670  is provided so as to surround the protruding portion  681  of the inverter housing  531 . That is, the end surface on the inner diameter side of the rotor cover  670  opposes an outer circumferential surface of the protruding portion  681 , and the sealing member  671  is provided therebetween. 
     In addition, the external connection terminal  632  that configures the bus bar module  533  passes through the boss portion  548  of the inverter housing  531  and extends to the hollow area of the boss portion  548 . In addition, the external connection terminal  632  passes through the housing cover  666  and extends towards the vehicle inner side (lower side in the drawing). 
     Furthermore, in the inverter housing  531 , the inlet passage  571  and the outlet passage  572  that communicate with the cooling water passage  545  are formed. The inlet passage  571  and the outlet passage  572  extend to the hollow area of the boss portion  548  and extend further towards the vehicle inner side (lower side in the drawing) than the housing cover  666  by a relay pipe  682 . In the present configuration, the pipe portion that extends from the housing cover  666  towards the vehicle inner side is the waterway port  574 . 
     According to the configurations in  FIG. 74( a )  and  FIG. 74( b ) , the rotor carrier  511  and the rotor cover  670  can be suitably rotated in relation to the inverter housing  531  while sealability of the interior space of the rotor carrier  511  and the rotor cover  60  is maintained. 
     In addition, in particular, according to the configuration in  FIG. 74( b ) , the inner diameter of the rotor cover  670  is smaller compared to that in the configuration in  FIG. 74( a ) . Therefore, the inverter housing  531  and the rotor cover  670  can be provided in two layers in the axial direction in a position that is further towards the vehicle inner side than the electrical module  532  is. Issues caused by electromagnetic noise that are a concern in the electrical module  532  can be suppressed. In addition, a sliding diameter of the sealing member  671  is decreased as a result of the decrease in the inner diameter of the rotor cover  670 . Mechanical loss in a rotation sliding portion can be suppressed. 
     (Modification 4 of the In-Wheel Motor) 
     A modification of the stator winding  521  will be described below.  FIG. 75  shows a modification related to the stator winding  521 . 
     As shown in  FIG. 75 , the stator winding  521  is wound by wave winding using a conductor material of which the lateral cross-section forms a rectangular shape, such that a long side of the conductor material is oriented to extend in the circumferential direction. 
     In this case, the conductors  523  of each phase that serve as the coil side in the stator winding  521  are arranged at predetermined pitch intervals for each phase and are connected to each other at the coil end. The conductors  523  that are adjacent to each other in the circumferential direction in the coil side are in contact with each other at the end surfaces in the circumferential direction or are closely arranged with a minute gap therebetween. 
     In addition, in the stator winding  521 , the conductor material is bent in the radial direction for each phase at the coil end. More specifically, the stator winding  521  (conductor material) is bent towards the radially inner side in a position that differs for each phase in the axial direction. As a result, interference among the phase windings of the U-phase, V-phase, and W-phase is prevented. 
     In the configuration in the drawing, the phase windings are made to differ only by an amount amounting to the thickness of the conductor material, and the conductor material is bent at a right angle towards the radially inner side for each phase. The length dimensions between both ends in the axial direction of the conductors  523  that are arrayed in the circumferential direction may be the same. 
     Here, when the stator core  522  is assembled to the stator winding  521  and the stator  520  is fabricated, a portion of the circular annular shape of the stator winding  521  may be detached so as to be disconnected (that is, the stator winding  521  becomes approximately C-shaped), and after the stator core  522  is assembled to the inner circumferential side of the stator winding  521 , the detached portion may be connected to each other and the stator winding  521  may be formed into the circular annular shape. 
     In addition to the foregoing, the stator core  522  can be divided into a plurality of pieces (such as three or more pieces) in the circumferential direction. The core pieces that are divided into a plurality of pieces can be assembled to the inner circumferential side of the stator winding  521  that is formed into the circular annular shape. 
     (Modification 5 of the In-Wheel Motor) 
     A modification related to the power converter that is integrally provided in the rotating electric machine  500  will be described below. 
     As prior art related to this type of power converter (power conversion apparatus), a power conversion apparatus that includes annular positive-electrode-side conductor and negative-electrode-side conductor is known, as shown in patent literature JP-A-2016-019346 and the like. 
     In the power conversion apparatus, a plurality of switch modules and a plurality of capacitor modules that are arranged in an annular shape are connected in parallel between the positive-electrode-side conductor and the negative-electrode-side conductor. In these modules, a capacitor group is formed by at least two capacitor modules that are adjacent in the circumferential direction. The capacitor modules are arranged densely inside the capacitor group. In addition, the capacitor modules are arranged sparsely between the capacitor groups. As a result, space for arranging other components is ensured between the capacitor groups. 
     However, when the capacitor modules are densely arranged inside the capacitor group, in the circumferential direction of the plurality of switch modules and the plurality of capacitor modules that are arranged in an annular shape, while the capacitor module is arranged so as to be adjacent on one side of the switch module, the capacitor module may not be arranged so as to be adjacent on the other side. 
     In this case, a current flows from the switch module so as to be concentrated at the capacitor that is included in the capacitor module on the one side that is closest to the switch module. An imbalance occurs in the currents that flows to the capacitors. As a result, an imbalance occurs in the amounts of heat generation in the capacitor modules, and thermal performance deteriorates. 
     To suppress imbalance in the amounts of heat generation in the capacitor modules, arranging the capacitor modules on both sides of the switch module can be considered. However, when the capacitances of the capacitors that are included in the capacitor modules that are arranged on both sides differ, even when the same amount of current flows to the capacitor modules on both sides from the switch module, the amount of heat generation in the capacitor module that includes the capacitor that has the smaller capacitance increases, and thermal performance deteriorates. 
     In the above-described patent literature (JP-A-2016-019346), the capacitance of the capacitor is not examined. The present example has been achieved with focus on such issues. A configuration in which imbalance in the amounts of heat generation in the capacitor modules in the power converter can be suppressed will be described below. 
     In the present example, the rotating electric machine  500  is configured to include the inverter  600  shown in  FIG. 59  as a power converter. The phase winding of each phase of the rotating electric machine  500  is connected to a direct-current power supply  605  through the inverter  600 . 
     As described above, the inverter  600  includes the serial-connection body that is made of the upper arm switch  601  and the lower arm switch  602  for each phase. An energization direction of the current that flows to the phase winding of each phase from the direct-current power supply  605  is controlled by the switching operation of the switches  601  and  602  based on the command signal form the control apparatus  607 . 
     In the inverter  600 , high-frequency vibrations that are generated in the current in accompaniment with the switching operation are suppressed by the capacitor  606 . For example, the capacitor  606  is a smoothing capacitor that is made of an electrolytic capacitor. For example, the direct-current power supply  605  is an assembled battery that is made of a plurality of lithium-ion storage batteries being connected in series. 
     In addition, as shown in  FIG. 50  and the like, as a basic structure in the inverter unit  530 , in the inverter housing  531 , a plurality of electrical modules  532  (a plurality of switch modules  532 A and a plurality of capacitor modules  532 B) are arranged so as to be arrayed in the circumferential direction along the inner circumferential surface of the cylindrical portion (outer peripheral wall WA 1 ) in the annular space that surrounds the rotation shaft  501 . 
     In addition, as shown in  FIG. 68  to  FIG. 70 , the bus bar module  533  is connected to these switch modules  532 A and capacitor modules  532 B. Specifically, the bus bar module  533  includes the first bus bar  641  that is connected to the high-potential-side power terminal  632 A and the second bus bar  642  that is connected to the low-potential-side power terminal  632 B. The module terminals  615  that are provided in the switch modules  532 A and the capacitor modules  532 B are each connected to the first bus bar  641  and the second bus bar  642 . 
     The first bus bar  641  and the second bus bar  642  are each formed into an annular shape and provided coaxially to the rotation shaft  501 . In addition, the first bus bar  641  is connected to the positive electrode side of the direct-current power supply  605  via the high-potential-side power terminal  632 A and the second bus bar  642  is connected to the negative electrode side of the direct-current power supply  605  via the low-potential-side power terminal  632 B. Here, the first bus bar  641  corresponds to a “positive-electrode-side conductor” and the second bus bar  642  corresponds to a “negative-electrode-side conductor.” 
     As a result of the above-described configuration, in the inverter  600 , the upper and lower arm switches  601  and  602  of each phase are connected in parallel, and the plurality of capacitors  606  are connected in parallel, between the first bus bar  641  and the second bus bar  642 . 
     Characteristic points of the arrangement of the switch modules  532 A and the capacitor modules  532 B in the inverter unit  530  will be described below. 
       FIG. 76  is a diagram of a state of arrangement of the switch modules  532 A and the capacitor modules  532 B. Here, in  FIG. 76 , the switch module  532 A, of the switch modules  532 A and the capacitor modules  532 B, is indicated by a thick-lined frame (this similarly applies in drawings hereafter). 
     In the present example, the numbers of the switch modules  532 A and the capacitor modules  532 B that are provided in the inverter housing  531  are the same. The configuration is that in which three switch modules  532 A and three capacitor modules  532 B are used. In addition, the capacitances of the capacitors  606  are equal to one another the capacitor modules  532 B. Here, in  FIG. 76 , the switch modules  532 A of the phases (U-phase, V-phase, and W-phase) are a switch module  532 A_U, a switch module  532 A_V, and a switch module  532 A_W. 
     In  FIG. 76 , the switch modules  532 A and the capacitor modules  532 B are arranged in an annular manner so as to be arrayed on a virtual circle KE of which the axial center of the rotating electric machine  500  is the center point. These modules  532 A and  532 B are arranged such that an interval X between the modules in the circumferential direction on the virtual circle KE is an even interval. 
     Here, for example, the interval X is a distance between the center positions of two modules that are adjacent in the circumferential direction. Here, the interval between the modules in the circumferential direction may be defined by an angle interval  0  on the virtual circle KE of which the rotation shaft  501  is the center. 
     The modules  532 A and  532 B are arranged such that the switch module  532 A of each phase and the capacitor modules  532 B alternate in the circumferential direction. When viewed in a clockwise direction in the drawing, the modules  532 A and  532 B are arranged in order of the switch module  532 A U, the capacitor module  532 B, the switch module  532 A V, the capacitor module  532 B, the switch module  532 A W, and the capacitor module  532 B 
     The first bus bar  641  on the high potential side is connected to the positive electrode terminals (module terminals  615  on the positive electrode side) of the modules in the order of array of the modules in the circumferential direction. The first bus bar  641  is connected to the positive electrode terminals of the modules at connection positions that differ from one another. In the first bus bar  641 , the connection positions to the positive electrode terminals are arranged at equal intervals in the circumferential direction. 
     In addition, the second bus bar  642  on the low potential side is connected to the negative electrode terminals (module terminals  615  on the negative electrode side) of the modules in the order of array of the modules in the circumferential direction. The second bus bar  642  is connected to the negative electrode terminals of the modules at connection positions that differ from one another. In the second bus bar  642 , the connection positions to the negative electrode terminals are arranged at equal intervals in the circumferential direction. 
     As described above, because the switch modules  532 A and the capacitor modules  532 B are arranged so as to be alternately arrayed in the circumferential direction, the capacitor modules  532 B are arranged on both sides of each switch module  532 A. In addition, the capacitances of the capacitors  606  that are included in the capacitor modules  532 B are set to be equal to one another. 
     In this case, the impedance in the capacitor  606  viewed from the switch module  532 A is equal among the capacitor modules  532 B. Therefore, when a current flows to the bus bars  641  and  642  in accompaniment with the switching operation of the switches  601  and  602  included in the switching modules  532 An approximately equal currents flow to the capacitors  606  on both sides from the switching module  532 A. As a result, the amounts of heat generation in the capacitor modules  532 B are equalized, and the imbalance in the amounts of heat generation in the capacitor modules  532 B is suppressed. 
     As a comparative example,  FIG. 77  shows a configuration in which the plurality of switch modules  532 A and the plurality of capacitor modules  532 B are arranged in a concentrated manner in the circumferential direction. 
     In the present configuration, the impedance in the capacitor  606  viewed from the switch module  532 A differs among the capacitor modules  532 B. Therefore, when the current flows to the bus bars  641  and  642  in accompaniment with the switching operation of the switches  601  and  602  included in the switching modules  532 A, the currents flow so as to be concentrated at the capacitor  606  of the capacitor module  532 B of which a path length from the switch module  532 A is the shortest, that is, the capacitor  606  of which the inductance in the bus bars  641  and  642  is the smallest. 
     In  FIG. 77 , the currents that flow to the capacitors  606  of the capacitor modules  532 B on both sides, among the three capacitor modules  532 B that are arrayed in the circumferential direction, are large. Meanwhile, the current that flows to the capacitor module  532 B and the capacitor  606  that are positioned in the center in the circumferential direction is small. 
     In this manner, in the comparative example, an imbalance occurs in the currents that flow to the capacitors  606  of the capacitor modules  532 B. As shown in  FIG. 78 , a correlation is present between the current that flows to the capacitor  606  and the amount of heat generation in the capacitor module  532 B. Therefore, when an imbalance occurs in the currents that flow to the capacitors  606 , an imbalance occurs in the amounts of heat generation in the capacitor modules  532 B. As a result, thermal performance of the capacitor modules  532 B deteriorates. 
       FIG. 79  shows frequency characteristics of a current amplification factor of the capacitor module  532 B, as an example of the thermal performance of the capacitor module  532 B. Here,  FIG. 79( a )  shows the frequency characteristics in the inverter  600  of the present example.  FIG. 79( b )  shows the frequency characteristics in an inverter that has the configuration of the comparative example in  FIG. 77 . 
     In  FIG. 79( b ) , the current amplification factor of the capacitor modules  532 B on both sides of the three capacitor modules  532 B that are arrayed in the circumferential direction is indicated by a broken line. The current amplification factor of the capacitor module  532 B in the center is indicated by a solid line. As is clear from the drawing, in the inverter of the comparative example, an imbalance in the amounts of heat generation in the capacitor modules  532 B occurs. 
     Therefore, a difference Δ occurs in the current amplification factors of the capacitor modules  532 B at a frequency ω that is greater than a predetermined frequency ωth. As a result, the currents that flow to the phase windings of the phases in the stator winding  521  being affected becomes a concern. 
     In contrast, as shown in  FIG. 79( a ) , the imbalance in the amounts of heat generation in the capacitor modules  532 B in the inverter  600  of the present example is suppressed. Therefore, the current amplification factors are equal in the capacitor modules  532 B at all frequencies ω. Consequently, variations in the currents that flows to the phase windings of the phases in the stator winding  521  are suppressed. 
     As a result of the above-described configuration, the following effects can be achieved. 
     In the inverter unit  530 , the plurality of switch modules  532 A and the plurality of capacitor modules  532 B are arranged in an annular shape, and the switch modules  532 A and the capacitor modules  532 B are connected to the annular first bus bar  641  and second bus bar  642 . In this configuration, the amounts of heat generation in the capacitor modules  532 B may become imbalanced as a result of the order of array of the modules in the circumferential direction. 
     In this regard, in the present example, the capacitor modules  532 B are arranged on both sides of each switch module  532 A, and the capacitances of the capacitors  606  that are included in the capacitor modules  532 B that are arranged on both sides are made equal to one another. As a result of this configuration, approximately equal currents flow from the switch module  532 A to the capacitors  606  on both sides of which the capacitances are equal. Therefore, the amounts of heat generation in the capacitor modules  532 B can be equalized, and the imbalance in the amounts of heat generation in the capacitor modules  532 B can be suppressed. 
     In addition, as a result of the imbalance in the amounts of heat generation in the capacitor modules  532 B being suppressed, cooling capabilities imparted to the rotating electric machine  500  can be reduced, and actualization of size reduction in accompaniment thereto can be expected. 
     In addition, the switch modules  532 A and the capacitor modules  532 B are each arranged along the inner circumferential surface of the cylindrical portion (outer peripheral wall WA 1 ) of the inverter housing  531 . Therefore, the modules are arranged on the radially inner side of the rotor  510  and the stator in the rotating electric machine  500 . In the rotating electric machine  500 , the electrical modules  532  that are constituent elements of the inverter  600  can be efficiently arranged. 
     In addition, the stator  520  and the inverter unit  530  are integrated. In this configuration, the switch modules  532 A and the capacitor modules  532 B being affected by the heat from the stator  520  can be considered. In this regard, because the arrangement of the capacitor modules  532 B is modified as described above, a suitable countermeasure against heat can be implemented. 
     The plurality of switch modules  532 A and the plurality of capacitor modules  532 B are configured to be arranged such that the switch modules  532 A and the capacitor modules  532 B are alternately arrayed in the circumferential direction. As a result of this configuration, the number of capacitor modules  532 B provided in the inverter unit  530  can be reduced, while the currents that flow to the capacitors  606  that are included in the capacitor modules  532 B are equalized. The configuration of the inverter unit  530  can be simplified. 
     The first bus bar  641  and the second bus bar  642  are configured such that the connection positions to the module terminals  615  of the modules  532 A and  532 B are at equal intervals in the circumferential direction. As a result of this configuration, the impedances in the capacitors  606  included in the capacitor modules  532 B on both sides when viewed from the switch module  532 A can be made equal. As a result, the currents that flow to the capacitors  606  can be made equal, and imbalance in the amounts of heat generation in the capacitor modules  532 B can be suppressed. 
     (Modification 1 Related to the Arrangement of the Electrical Modules) 
     In the inverter unit  530 , the switch modules  532 A and the capacitor modules  532 B may be arranged as shown in  FIG. 80 . In  FIG. 80 , the number of capacitor modules  532 B is twice that of the switch module  532 A, and the configuration is that in which three switch modules  532 A and six capacitor modules  532 B are used. The modules  532 A and  532 B are arranged such that the switch modules  532 A of the phases and two capacitor modules  532 B each alternate in the circumferential direction. In other words, two capacitor modules  532 B each are arranged between the switch modules  532 A that are distributively arranged in the circumferential direction. 
     The two capacitor modules  532 B that are arranged between the switch modules  532 A are connected to the first bus bar  641  and the second bus bar  642  at connection positions that differ from each other. In addition, the two capacitor modules  532 B between the switch modules  532 A are connected to positions that are at equal intervals in the circumferential direction in the first bus bar  641  and the second bus bar  642 . 
     In this case, compared to the configuration in which a single capacitor module  532 B is arranged between the switch modules  532 A that are distributively arranged in the circumferential direction (configuration in  FIG. 76 ), the inductance from the switch module  532 A to the capacitors  606  of the capacitor modules  532 B on both sides is smaller. 
     In the above-described configuration, because two capacitors  532 B each are adjacent to each other in the circumferential direction, the switch modules  532 A are not arranged on both sides of the capacitor module  532 B. Therefore, an issue in which the currents flow to the capacitor  606  that is included in the capacitor module  532 B from the switch modules  532 A on both sides, and excessive current flows to the capacitor  606  as a result can be suppressed. 
     In addition, as a result of the currents that flows to the capacitor  606  that is included in the capacitor module  532 B being suppressed, and the inductance from the switch module  532 A to the capacitors  606  on both sides being suppressed, the amount of heat generation in the capacitor module  532 B can be suitably suppressed. 
     (Modification 2 Related to the Arrangement of the Electrical Modules) 
     A configuration of a present example is shown in  FIG. 81 . Here,  FIG. 81  is a lateral cross-sectional view of the rotating electric machine  500 . 
     In the present example, in the inverter unit  530 , the protruding portion  573  that protrudes towards the radially inner side is formed in the cylindrical portion (outer peripheral wall WA 1 ), and the switch modules  532 A and the capacitor modules  532 B are arranged taking into consideration the presence of this protruding portion  573 . Here, as described above, the protruding portion  573  is provided with the inlet passage  571  and the outlet passage  572  that lead to the cooling water passage  545 . 
     In  FIG. 81 , three switch modules  532 A and four capacitor modules  532 B, of which the quantity is greater than that of the switch modules  532 A by one, are alternately arranged in the circumferential direction on the radially inner side of the cylindrical portion (outer peripheral wall WA 1 ) of the inverter housing  531 . 
     In the present example in particular, the capacitor modules  532 B are arranged on both sides sandwiching the protruding portion  573 , and the switch modules  532 A and the capacitor modules  532 B are alternately arranged in the circumferential direction between one capacitor module  532 B and the other capacitor module  532 B that are adjacent to the protruding portion  573 , on the side opposite the protruding portion  572 . 
     In addition, a distance between the two modules that are arranged with the protruding portion  573  therebetween, and a distance between two modules in another section differ on the virtual circle KE on which the modules  532 A and  532 B are arrayed. The former distance is greater than the latter distance. In other words, the area that includes the protruding portion  573  on the inner circumferential side of the cylindrical portion (outer peripheral wall WA 1 ) is an expanded portion EX in which the interval between modules that are arrayed in the circumferential direction is expanded compared to others. 
     Specifically, the modules are arranged so as to be arrayed in the circumferential direction with the interval between the modules in the circumferential direction as a first interval X 1  or a second interval X 2 . The second interval X 2  is a wider interval than the first interval Xl. 
     In this case, the interval between the modules that are adjacent in the circumferential direction without the protruding portion  573  therebetween is the first interval Xl. The interval between the modules that are adjacent in the circumferential direction with the protruding portion  573  therebetween, that is, the interval of the expanded portion is the second interval X 2 . Here, the interval between the modules in the circumferential direction may be defined as angle intervals θ 1  and θ 2  on the virtual circle KE, with the rotation shaft  501  as the center. 
     As a comparative example, a configuration in which the switch module  532 A is arranged on one side of the expanded portion EX in the circumferential direction and one of the capacitor modules  532 B that are arranged on both sides of the switch module  532 A is arranged on the other side is assumed. 
     In this case, in the switch module  532 A that is adjacent to the expanded portion EX, a difference occurs between the inductance in the bus bars  641  and  642  between the switch module  532 A and the capacitor module  532 B on the expanded portion EX side in the circumferential direction, and the inductance in the bus bars  641  and  642  between the switch module  532 A and the capacitor module  532 B on the opposite side. 
     In addition, as a result, the current flows in a concentrated manner to the capacitor module  532 B on the side opposite the expanded portion EX, of the capacitor modules  532 B on both sides during energization of the switch module  532 A that is adjacent to the expanded portion EX. An imbalance occurs in the amounts of heat generation in the capacitor modules. 
     In contrast, in the present example, because the capacitor modules  632 B are arranged on both sides sandwiching the expanded portion EX, the switch module  532 A being arranged on one side of the expanded portion EX in the circumferential direction is suppressed. That is, the capacitor modules  532 B are arranged on both sides sandwiching the expanded portion EX. Therefore, even in the expanded portion EX is provided, occurrence of an imbalance in the amounts of heat generation in the capacitor modules  532 B can be suppressed. 
     (Modification 3 related to the arrangement of the electrical modules) 
     A configuration of a present example is shown in  FIG. 82 . In the present example, the number of capacitor modules  532 B is twice that of the switch modules  532 A, and three switch modules  532 A and six capacitor modules  532 B are used. 
     In addition, the six capacitor modules  532 B are divided into twos, and the two capacitor modules  532 B each are arranged between the switch modules  532 A that are distributively arranged in the circumferential direction. For example, the two capacitor modules  532 B each are arranged in an array in the radial direction or the axial direction in the cylindrical portion (outer peripheral wall W 1 ). 
     The two capacitor modules  532 B each that are provided between the switch modules  532 A are each connected to the first bus bar  641  and the second bus bar  642  in the same connection position. As a specific configuration thereof, for example, in the bus bars  641  and  642 , three connection terminals for switch-module connection and three connection terminals for capacitor-module connection are alternately provided at equal intervals. 
     In addition, the module terminals of the switch modules  532 A may be connected one each to the connection terminals for switch-module connection, and the module terminals of the capacitor modules  532 B may be connected two each to the connection terminals for capacitor-module connection. 
     For example, two capacitor modules  532 B are arranged between the U-phase switch module  532 A_U and the V-phase switch module  532 A_V The two capacitor modules  532 B are connected to the bus bars  641  and  642  in the same connection position. In this case, in the two capacitor modules  532 B between the switch modules  532 A_U and  532 A_V, inductances in relation to the switch modules  532 A_U and  532 A_V are equal. 
     In addition, the configurations between the V-phase switch module  532 A_V and the W-phase switch module  532 A_W, and the W-phase switch module  532 A_W and the U-phase switch module  532 A_U are also similar. 
     Furthermore, in the two capacitor modules  532 B between the switch modules  532 A that are distributively arranged in the circumferential direction, the capacitors  606  that are included in the capacitor modules  532 B generate a composite capacitance that is obtained by the capacitances thereof being added. In addition, the composite capacitances are equal to each other on both sides of the switch module  532 A. 
     As a result of the above-described configuration, when the two capacitor modules  532 B are arranged between the switch modules  532 A that are distributively arranged in the circumferential direction, as a result of the connection positions of the capacitor modules  532 B to the bus bars  641  and  642  being the same, inductance can be matched between the capacitors  606  that are included in the capacitor modules  532 B. Therefore, the currents can be equally supplied to the capacitor modules  532 B, and an imbalance in the amounts of heat generation in the capacitor modules  532 B can be suppressed. 
     Capacitor capacitance between the switch modules  532 A that are arranged in the dispersed manner in the circumferential direction is set based on the composite capacitance of the capacitors  606  included in the two capacitor modules  532 B. Therefore, compared to a case in which the capacitor capacitance is generated by a single capacitor  606 , the capacitor capacitance between the switch modules  532 A can be suitably adjusted. 
     Here, three or more capacitor modules  532 B each may be arranged between the switch modules  532 A that are distributively arranged in the circumferential direction. 
     In this case, even when the quantity of the capacitor modules  532 B is three or more, as a result of these capacitor modules  532 B being connected to the bus bars  641  and  642  in the same position, the inductances can be matched among the capacitors  606  that are included in these capacitor modules  532 B. Consequently, the currents can be equally supplied to the capacitor modules  532 B, and an imbalance in the amounts of heat generation in the capacitor modules  532 B can be suppressed. 
     (Other Modifications Related to the Arrangement of the Electrical Modules) 
     The rotating electric machine  500  is not limited to a three-phase rotating electric machine and may be a rotating electric machine that has two phases, or four or more phases. Int his case, the quantity of the switch modules  532 A can be set based on the number of phases of the rotating electric machine  500 . The quantity of capacitor modules  532 B can be set based on the quantity of the switch modules  532 A. 
     The rotating electric machine  500  is not limited to the outer-rotor type and may be the inner-rotor type. In addition, a connection method for the stator winding  521  in the rotating electric machine  500  is not limited to the star connection and may be an open delta connection. 
     The switch module  532 A is not limited to that which includes a single serial-connection body made of the switches  601  and  602 . 
     As shown in  FIG. 83( a ) , the switch module  532 A may be that which includes a plurality of serial-connection bodies. Furthermore, as shown in  FIG. 83( b ) , a snubber capacitor  608  for suppressing surge voltages may be connected in parallel to the serial-connection body. Here, the capacitance of the snubber capacitor  608  is less than the capacitance of the capacitor  606  included in the capacitor module  532 B. Therefore, high-frequency vibrations that are generated in the current as a result of the switching operation cannot be suppressed by the snubber capacitor  608 . 
     When the snubber capacitor  608  is connected in parallel to the serial-connection body, the switch modules  532 A and the capacitor modules  532 B are preferably arranged so as to be alternately arrayed in the circumferential direction. As a result, the amounts of current at the capacitors  606  that are included in the capacitor modules  532 B can be suitably equalized. An imbalance in the amounts of heat generation in the capacitor modules  532 B can be suppressed with certainty. 
     In the above-described configuration, the first bus bar  641  and the second bus bar  642  of the bus bar module  533  have a circular annular shape. However, the first bus bar  641  and the second bus bar  642  may have a polygonal annular shape. In short, the first bus bar  641  and the second bus bar  642  are merely required to be annular. In addition, although the first bus bar  641  and the second bus bar  642  form closed annular shapes, the first bus bar  641  and the second bus bar  642  may have an approximately C-shaped annular shape in which a portion of the annular shape is cut. 
     Members that are arranged in the expanded portion EX is not limited to the protruding portion  573 , and may be a wiring member for drawing the power terminals  632 A and  632 B, or the control apparatus  607 . 
     (Other Modifications) 
     For example, as shown in  FIG. 50 , the inlet passage  571  and the outlet passage  572  of the cooling water passage  545  are provided so as to be collected in a single location in the rotating electric machine  500 . However, this configuration may be modified such that the inlet passage  571  and the outlet passage  572  are each provided in positions that differ in the circumferential direction. 
     For example, the inlet passage  571  and the outlet passage  572  may be provided in positions that differ by  180  degrees in the circumferential direction. Alternatively, a plurality of at least either of the inlet passage  571  and the outlet passage  572  may be provided. 
     In the vehicle wheel  400  according to the above-described embodiment, the rotation shaft  501  protrudes towards one side in the axial direction of the rotating electric machine  500 . However, the configuration may be modified. The rotation shaft  501  may protrude towards both sides in the axial direction. As a result, for example, a suitable configuration can be implemented in a vehicle in which at least either of the front and the rear of the vehicle has a single wheel. 
     An inner-rotor-type rotating electric machine can also be used as the rotating electric machine  500  that is used in the vehicle wheel  400 . 
     The disclosure of the present specification is not limited to the embodiments given as examples. The disclosure includes the embodiments given as examples, as well as modifications by a person skilled in the art based on the embodiments. 
     For example, the disclosure is not limited to the combinations of components and/or elements described according to the embodiments. The disclosure can be carried out using various combinations. The disclosure may have additional sections that can be added to the embodiments. The disclosure includes that in which a component and/or element according to an embodiment has been omitted. The disclosure includes replacements and combinations of components and/or elements between one embodiment and another embodiment. 
     The technical scope that is disclosed is not limited to the descriptions according to the embodiments. Several technical scopes that are disclosed are cited in the scope of claims. Furthermore, the technical scopes should be understood to include all modifications within the meaning and scope of equivalency of the scope of claims. 
     While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to the embodiments and constructions. The present disclosure is intended to cover various modification examples and modifications within the range of equivalency. In addition, various combinations and configurations, and further, other combinations and configurations including more, less, or only a single element thereof are also within the spirit and scope of the present disclosure.