Patent Publication Number: US-2017366059-A1

Title: Power supply ring

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2016-120464 filed in Japan on Jun. 17, 2016. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a power supply ring. 
     2. Description of the Related Art 
     Conventionally, an annular power supply ring connected to an annular stator in a rotating machine for each phase and constituting a stator unit together with the stator has been known. The power supply ring is responsible for supplying a current for each phase between the stator and an inverter. The power supply ring includes an annular bus ring (conductor) for each phase, a power supply terminal provided for each bus ring to electrically connect the bus ring to the inverter side, and a coil connection terminal which electrically connects the bus ring to the respective stator coils for each phase. By concentrically arranging the bus rings of each phase side by side in a radial direction, the power supply ring can suppress an increase in the body size of the stator unit in an axial direction. This kind of power supply ring is disclosed in, for example, Japanese Patent Application Laid-open No. 2007-135339. 
     Incidentally, in the conventional power supply ring, in order to ensure insulation properties between the respective bus rings, an annular spacer is interposed between the bus rings which are adjacent to each other in the radial direction. For this reason, in the conventional power supply ring, there is risk of an increase in the body size in the radial direction, and there is a possibility of an increase in the body size of the stator unit in the radial direction. Further, the conventional power supply ring is disposed on the outside in the radial direction with respect to the stator coil, which also leads to an increase in the body size of the stator unit in the radial direction. 
     SUMMARY OF THE INVENTION 
     Thus, an object of the present invention is to provide a power supply ring capable of suppressing an increase in the body size of the stator unit. 
     A power supply ring according to one aspect of the present invention includes a bus ring which is provided for each phase of a rotating machine having a plurality of stator coils arranged side by side in an annular shape and extends in a circumferential direction to extend along the plurality of stator coils; a power supply terminal for each phase which electrically connects the bus ring to a power source side; and a plurality of coil connection terminals which electrically connects the bus ring to each of the stator coils of the same phase, wherein each of the bus rings is concentrically laminated on an annular body including the plurality of stator coils in an axial direction. 
     According to another aspect of the present invention, in the power supply ring, it is preferable that each of the bus rings is disposed to be placed between an outer wall surface side and an inner wall surface side on the annular body including the stator coil when viewed in the axial direction. 
     According to still another aspect of the present invention, in the power supply ring, it is preferable that each of the bus rings is concentrically disposed side by side in a radial direction, a connecting position with the power supply terminal and a connecting position with the coil connection terminal being provided on the same plane as a main body portion extending in the circumferential direction, and the power supply terminal and the coil connection terminal are disposed such that a longitudinal direction of the terminals extends along a plane orthogonal to the axis. 
     According to still another aspect of the present invention, it is preferable that the power supply ring further includes a plurality of holding members which collectively bundles and holds each of the bus rings in a state of being spaced from each other in the radial direction. 
     According to still another aspect of the present invention, in the power supply ring, it is preferable that the holding member has an engaging portion which fixes each of the bus rings to the stator by being engaged with a portion to be engaged provided in the stator. 
     According to still another aspect of the present invention, in the power supply ring, it is preferable that the portion to be engaged is provided in a coil insulator of the stator coil. 
     According to still another aspect of the present invention, in the power supply ring, the bus ring includes a conductive member extending in a circumferential direction along the plurality of stator coils, and an insulating coating which covers the conductive member, and the coating is an ultraviolet cured coating formed of an ultraviolet curable resin. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a power supply ring and a stator of an embodiment; 
         FIG. 2  is a perspective view illustrating a state in which the power supply ring of the embodiment is assembled to the stator; 
         FIG. 3  is a top view illustrating a state in which the power supply ring of the embodiment is assembled to the stator; 
         FIG. 4  is a side view of the power supply ring of the embodiment; 
         FIG. 5  is an exploded perspective view of the power supply ring of the embodiment disassembled for each bus ring; 
         FIG. 6  is an exploded perspective view illustrating a U-phase bus ring; 
         FIG. 7  is an exploded perspective view illustrating a V-phase bus ring; 
         FIG. 8  is an exploded perspective view illustrating a W-phase bus ring; 
         FIG. 9  is an exploded perspective view illustrating a neutral-phase bus ring; 
         FIG. 10  is an exploded perspective view illustrating a state before a holding member is attached; 
         FIG. 11  is a perspective view of the holding member; 
         FIG. 12  is a side view of the holding member; 
         FIG. 13  is a top view of the holding member; and 
         FIG. 14  is a side view illustrating a modified embodiment of the holding member. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of a power supply ring according to the present invention will be described in detail with reference to the drawings. The present invention is not limited by the embodiments. 
     Embodiment 
     An embodiment of the power supply ring according to the present invention will be described with reference to  FIGS. 1 to 14 . 
     The reference sign  1  in  FIGS. 1 to 4  indicates a power supply ring of the embodiment. The power supply ring  1  is a power supply structure that is responsible for supplying current for each phase of a rotating machine between, for example, a stator  100  of the rotating machine mounted on a vehicle and a power source (not illustrated) of a secondary battery or the like. For example, when the rotating machine is operating as an electric motor, electric power sent from an inverter of the secondary battery side is supplied to the rotating machine via the power supply ring  1 . Further, when the rotating machine is operating as a generator, such as during regeneration, the electric power generated by the rotating machine is supplied to the inverter via the power supply ring  1 , and is charged to the secondary battery via the inverter. By being attached to the stator  100 , the power supply ring  1  and the stator  100  form a stator unit. 
     Here, the stator  100  includes a stator core  101 . The stator core  101  has a plurality of teeth  101   a  arranged side by side in an annular shape (that is, in a circumferential direction) at intervals. The respective teeth  101   a  form an annular teeth group. The stator core  101  further has an annular body  101   b  which integrally holds the respective teeth  101   a  from the outer circumferential side of the teeth group. The stator core  101  of this example is provided as a laminated body of a plate-like stator core plate which has an annular portion, and a plurality of teeth portions projecting from the inner circumferential side of the annular portion toward the center of the annular form and spaced apart from each other in the circumferential direction of the annular form. In the stator core  101 , the laminated portion of the teeth portion forms, for example, rectangular teeth  101   a , and the laminated portion of the annular portion forms a cylindrical annular body  101   b.    
     The stator  100  includes a plurality of stator coils  102  in which each conductive wire is wound around each of the teeth  101   a . Each of the stator coils  102  is arranged side by side in an annular shape (that is, in the circumferential direction) in accordance with each of the teeth  101   a  to form an annular stator coil group. In the stator  100  of this example, a tubular coil insulator  103  is fitted to each of the teeth  101   a , and wire materials are wound around the coil insulator  103 , respectively, thereby forming the respective stator coils  102 . Both ends of the stator coil  102  are drawn out at equivalent positions as lead wires  102   a  ( FIGS. 1 and 2 ). As it will be described later, the power supply ring  1  is substantially concentrically laminated on the stator coil group. Each lead wire  102   a  is drawn out to a position on which the power supply ring  1  is laminated. 
     Here, the combinations of the teeth  101   a , the stator coil  102 , and the coil insulator  103  of each phase (here, three phases of a U-phase, a V-phase, and a W-phase) of the rotating machine of this example are disposed at four positions shifted from each other by 90 degrees. 
     The power supply ring  1  is formed into an annular shape in conformity with the annular stator  100 . Hereinafter, unless otherwise mentioned, a direction along an axis P ( FIG. 4 ) of an annular center axis is referred to as an axial direction, a direction around the axis with the axis P as a center is referred to as a circumferential direction, and a direction orthogonal to the axis P is referred to as a radial direction. 
     The power supply ring  1  includes conductors (hereinafter, referred to as “bus rings”)  10   u ,  10   v , and  10   w  for each of the phases of the rotating machine (three phases of U-phase, V-phase and W-phase) extending in the circumferential direction along a plurality of stator coils  102  (an annular stator coil group), metallic power supply terminals  21   u ,  21   v  and  21   w  for each phase which electrically connect the bus rings  10   u ,  10   v , and  10   w  to a power source side inverter (not illustrated), and a plurality of metallic coil connection terminals  22  which electrically connect the bus rings  10   u ,  10   v , and  10   w  to each of the stator coils  102  of the same phase ( FIG. 3 ). 
     Further, the power supply ring  1  of the present embodiment is also provided with a neutral-phase bus ring (hereinafter, referred to as “neutral-phase bus ring”)  10   n . Like the bus rings  10   u ,  10   v , and  10   w , the neutral-phase bus ring  10   n  extends in the circumferential direction along a plurality of stator coils  102  (the annular stator coil group). In the power supply ring  1 , like the bus rings  10   u ,  10   v , and  10   w , a plurality of coil connection terminals  22  is also connected to the neutral-phase bus ring  10   n.    
     The bus rings  10   u ,  10   v , and  10   w  of the respective phases of this example form a main body portion to have an annular ring shape or a Landolt ring shape extending in the circumferential direction on a concentric circle, respectively, and are disposed concentrically on the annular body made up of a plurality of stator coils  102  (an annular stator coil group). Meanwhile, the neutral-phase bus ring  10   n  forms a main body portion to have an arc shape extending in the circumferential direction, and is disposed concentrically on the annular body. Therefore, in the power supply ring  1 , the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  are concentrically disposed. 
     The bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  are concentrically arranged side by side. In the power supply ring  1 , any arrangement may be adopted, but in order to suppress an increase in the body size in the axial direction, the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  are concentrically arranged side by side in the radial direction ( FIGS. 1 to 3 ), respectively. Therefore, in the power supply ring  1 , since the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  are disposed on the same plane, it is possible to suppress the increase in the body size in the axial direction. Therefore, in the power supply ring  1 , it is possible to suppress an increase in the body size of the stator unit in the axial direction. 
     However, depending on the arrangement of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  with respect to the stator  100  (for example, when the bus rings are disposed radially outside with respect to the annular stator coil group), there is a risk of causing an increase in the body size of the stator unit in the radial direction. Therefore, the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  are concentrically laminated on an annular body including a plurality of stator coils  102  (the annular stator coil group) in the axial direction. Therefore, in the power supply ring  1 , regardless of the arrangement of the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n , it is possible to suppress an increase in the body size of the stator unit in the radial direction. At the laminated position, it is desirable to dispose each of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  so that at least the main body portion is located between the outer wall surface side and the inner wall surface side of the annular body, when viewed in the axial direction. In the power supply ring  1 , by disposing the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  as described above, it is possible to further suppress an increase in the body size of the stator unit in the radial direction. 
     The bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  of this example are concentrically arranged side by side in the radial direction, respectively, and are laminated concentrically on the annular body of the stator coil  102  in the axial direction. Therefore, in the power supply ring  1 , it is possible to suppress increases in the body size of the stator unit in the axial direction and the body size of the stator unit in the radial direction. 
     The power supply terminals  21   u ,  21   v , and  21   w  of this example are prepared as crimping terminals crimped by caulking or the like, and are crimped to the respective connecting positions  11   a  of the bus rings  10   u ,  10   v , and  10   w  which are connecting targets. The bus rings  10   u ,  10   v , and  10   w  of this example are provided with connecting positions  11   a  on the same plane as the main body portion extending in the circumferential direction so as to suppress the increase in the body size in the axial direction. Here, the connecting position  11   a  is made to protrude radially outward on the same plane. Further, the power supply terminals  21   u ,  21   v , and  21   w  of this example are disposed so that the longitudinal direction thereof extends along a plane orthogonal to the axis P, and are crimped to the connecting position  11   a . Therefore, in the power supply ring  1 , since the respective power supply terminals  21   u ,  21   v , and  21   w  are disposed on the same plane as the bus rings  10   u ,  10   v , and  10   w  of the respective phases, it is possible to suppress the increase in the body size in the axial direction. Therefore, in the power supply ring  1 , it is possible to suppress an increase in the body size of the stator unit in the axial direction. 
     The coil connection terminals  22  of the bus rings  10   u ,  10   v , and  10   w  of the respective phases electrically connect the bus rings  10   u ,  10   v , and  10   w  to the stator coils  102  of the same phase. In this example, as the coil connection terminal  22 , a first coil connection terminal  22 A and a second coil connection terminal  22 B are provided ( FIGS. 5 to 8 ). The first coil connection terminal  22 A is interposed between the bus rings  10   u ,  10   v , and  10   w  of the same phase and the lead wire  102   a  at one end of the stator coil  102  to electrically connect the bus rings and the lead wire, and the second coil connection terminal  22 B is interposed between the bus rings  10   u ,  10   v , and  10   w  of the same phase and the lead wire  102   a  at the other end of the stator coil  102  to electrically connect the bus rings and the lead wire. 
     The coil connection terminal  22  of the neutral-phase bus ring  10   n  electrically connects the bus rings  10   u ,  10   v , and  10   w  of each phase via the stator coil  102  of the same phase. In this example, a second coil connection terminal  22 B is provided as the coil connection terminal  22  ( FIGS. 5 and 9 ). The second coil connection terminal  22 B of the neutral-phase bus ring  10   n  is electrically connected to the lead wire  102   a  of the other end of the stator coils  102  of each of the U-phase, V-phase and W-phase to which only the first coil connection terminals  22 A of the bus rings  10   u ,  10   v , and  10   w  are connected. 
     Like the power supply terminals  21   u ,  21   v , and  21   w , the coil connection terminals  22  (the first coil connection terminals  22 A and the second coil connection terminals  22 B) of this example are disposed so that the longitudinal direction thereof extends along a plane orthogonal to the axis P, and are crimped to the connecting positions  11   b  of each of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  as the connecting targets by caulking or the like. The connecting position  11   b  is provided in the main body portions of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n . Therefore, in the power supply ring  1 , the respective coil connection terminals  22  (the first coil connection terminals  22 A and the second coil connection terminals  22 B) are disposed on the same plane as the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n . Thus, from this point, it is also possible to suppress an increase in body size in the axial direction. Therefore, in the power supply ring  1 , it is possible to suppress an increase in the body size of the stator unit in the axial direction. 
     Specifically, the first coil connection terminal  22 A and the second coil connection terminal  22 B of this example are made of a metallic plate material. The first coil connection terminal  22 A and the second coil connection terminal  22 B form connecting units to the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  in the same shape. The connecting unit is crimped so as to cover the outer peripheral surface of the connecting position  11   b  of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n . The first coil connection terminal  22 A and the second coil connection terminal  22 B have a piece extending from the connecting unit to the connecting position with the stator coil  102 . Here, the connecting position  11   b  to which the first coil connection terminal  22 A is crimped is disposed on the radially inner side than the connecting position  11   b  to which the second coil connection terminal  22 B is crimped. Therefore, the first coil connection terminal  22 A has a longer piece than the second coil connection terminal  22 B. The piece of the coil connection terminal  22  (the first coil connection terminal  22 A and the second coil connection terminal  22 B) is connected to the lead wire  102   a  of the stator coil  102  by welding. In this example, the piece is placed on the lead wire  102   a , and the piece and the lead wire  102   a  are connected by ultrasonic welding. Further, the connection therebetween may be performed by crimping such as caulking, and the coil connection terminals  22  may be formed in a shape corresponding to the connection form. 
     Hereinafter, the configurations of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  will be described, and a specific example of the power supply ring  1  will be illustrated. 
     Each of the bus rings  10   u ,  10   v , and  10   w  includes a conductive member  11  extending in the circumferential direction along an annular stator coil group, and an insulating coating  12  which covers the conductive member  11  ( FIGS. 5 to 8 ). A plurality of conductive members  11  is used in each of the bus rings  10   u ,  10   v , and  10   w . In each of the bus rings  10   u ,  10   v , and  10   w , the conductive members  11  thereof are arranged side by side along the circumferential direction of the annular stator coil group, and the adjacent conductive members  11  are electrically connected to each other via the stator coil  102 . The coating  12  is provided in the portions of the conductive members  11  of the bus rings  10   u ,  10   v , and  10   w , except for the connecting position  11   a  with the power supply terminals  21   u ,  21   v , and  21   w  and the connecting position  11   b  with the coil connection terminals  22 . 
     Further, similarly to the bus rings  10   u ,  10   v , and  10   w , the neutral-phase bus ring  10   n  includes a conductive member  11  extending in the circumferential direction along an annular stator coil group, and an insulating coating  12  which covers the conductive member  11  ( FIGS. 5 and 9 ). In the neutral-phase bus ring  10   n , two conductive members  11  are used. In the neutral-phase bus ring  10   n , the conductive members  11  are arranged side by side along the circumferential direction of the annular stator coil group. The coating  12  is provided in the portion of the conductive member  11  of the neutral-phase bus ring  10   n , except for the connecting position  11   b  with the coil connection terminal  22 . 
     As the conductive member  11 , it is conceivable to use a member molded by bending a single metallic rod or a member molded by bending a bundle of a plurality of metallic strands. In the present embodiment, the latter bundle of the strands having flexibility is used to improve the assembling workability to the stator  100 . 
     Here, the power supply ring  1  enters the lubricating oil of the rotating machine. Therefore, as the material of the coating  12 , a material having insulation properties and oil resistance (synthetic resin or the like) is used. It is desirable that the coating  12  be made flexible so as not to hinder the flexibility of the conductive member  11 . As a result, the power supply ring  1  of the present embodiment has high follow-up performance with respect to the shape of the stator  100 , and it is possible to improve the assembling workability to the stator  100 . In addition, due to its flexibility, the power supply ring  1  can absorb vibration against an input from the outside. 
     For example, as the coating  12 , it is conceivable to adopt coating in which a portion except the connecting positions  11   a  and  11   b  is removed from the insulating coating (for example, a fluororesin coating) for covering the entire outer peripheral surface of the conductive member  11 , coating such as a heat shrinkable tube attached except the connecting positions  11   a  and  11   b , and the like. Further, an ultraviolet cured coating made of an ultraviolet curable resin may be applied to the coating  12 . In this case, the ultraviolet curable resin is applied so as to cover the entire outer peripheral surface of the conductive member  11 , and the portion of the ultraviolet curable resin except the connecting positions  11   a  and  11   b  is irradiated with the ultraviolet rays. As a result, the coating (ultraviolet cured coating)  12  made of an ultraviolet curable resin is formed in a portion except the connecting positions  11   a  and  11   b  of the conductive member  11 . In this example, the ultraviolet cured coating is used. As a result, the coating (ultraviolet cured coating)  12  can be made thinner than other forms (for example, fluororesin coating), while ensuring the insulation properties and the oil resistance. Accordingly, it is possible to suppress an increase in body size of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  in the axial direction and in the radial direction. Therefore, in the power supply ring  1 , it is possible to suppress an increase in the body size of the stator unit in the axial direction and in the radial direction. 
     The bus rings  10   u ,  10   v , and  10   w  of the respective phases include, as the conductive member  11 , a power supply side conductive member to which the power supply terminals  21   u ,  21   v , and  21   w  of the same phase are connected, and at least one coupling conductive member arranged side by side in the circumferential direction with respect to the power supply side conductive member. The power supply side conductive member has an electrical connecting position  11   a  with the power supply terminals  21   u ,  21   v , and  21   w  of the same phase provided at one end thereof, and an electrical connecting position  11   b  with the first coil connection terminal  22 A provided at the other end thereof. Further, the coupling conductive member has electrical connecting positions  11   b  with the second coil connection terminals  22 B provided at both ends thereof. 
     As illustrated in  FIGS. 5 and 6 , the U-phase bus ring  10   u  has a first conductive member  11   u   1  and a second conductive member  11   u   2  as the power supply side conductive members. The first conductive member  11   u   1  extends along one circumferential direction with respect to the position of the power supply terminal  21   u  of the same phase. The second conductive member  11   u   2  extends along the other circumferential direction with respect to the position of the power supply terminal  21   u . Each of the first conductive member  11   u   1  and the second conductive member  11   u   2  has a connecting position  11   a  with the power supply terminal  21   u  of the same phase at one end, and a connecting position  11   b  with the first coil connection terminal  22 A at the other end. In the first conductive member  11   u   1  and the second conductive member  11   u   2 , a coating  12   u  is provided at a location except the connecting positions  11   a  and  11   b  of both ends thereof. 
     The connecting positions  11   a  of each of the first conductive member  11   u   1  and the second conductive member  11   u   2  are adjacent to each other in a state of making the axial directions match each other, and extend toward the outer side of a circular ring shape in the radial direction. The first conductive member  11   u   1  and the second conductive member  11   u   2  are integrated by crimping a single power supply terminal  21   u  to each connecting position  11   a  by caulking or the like. Meanwhile, the connecting positions  11   b  of each of the first conductive member  11   u   1  and the second conductive member  11   u   2  are disposed in the vicinity of the adjacent separate U-phase stator coil  102 , respectively. In this example, the connecting position  11   b  and the first coil connection terminal  22 A are laminated on the stator coil  102  in the axial direction, and the lead wire  102   a  at one end of the stator coil  102  and the first coil connection terminal  22 A are electrically connected to each other. 
     Furthermore, the bus ring  10   u  has a third conductive member  11   u   3  and a fourth conductive member  11   u   4  as the coupling conductive members. The third conductive member  11   u   3  is arranged in parallel to the first conductive member  11   u   1  along the one circumferential direction. The fourth conductive member  11   u   4  is arranged in parallel to the second conductive member  11   u   2  along the other circumferential direction. The third conductive member  11   u   3  and the fourth conductive member  11   u   4  electrically connect the U-phase stator coil  102  which is adjacent in the circumferential direction. Therefore, in the bus ring  10   u , at least one third conductive member  11   u   3  and at least one fourth conductive member  11   u   4  are provided in accordance with the number of poles. Both ends of each of the third conductive member  11   u   3  and the fourth conductive member  11   u   4  are the connecting positions  11   b  with the coil connection terminal  22 . In the third conductive member  11   u   3  and the fourth conductive member  11   u   4 , coatings  12   u  are provided at a place except the connecting positions  11   b  at both ends thereof. 
     The bus ring  10   u  is provided with a single third conductive member  11   u   3  and a single fourth conductive member  11   u   4 . In the bus ring  10   u , the first conductive member  11   u   1  and the third conductive member  11   u   3  are connected to each other, and the second conductive member  11   u   2  and the fourth conductive member  11   u   4  are connected to each other. 
     The connecting position  11   b  at one end of the third conductive member  11   u   3  and the second coil connection terminal  22 B are axially laminated on the U-phase stator coil  102 , to which the first coil connection terminal  22 A at the other end of the first conductive member  11   u   1  is connected. Further, the second coil connection terminal  22 B is electrically connected to the lead wire  102   a  at the other end of the stator coil  102 . In other words, the first coil connection terminal  22 A and the second coil connection terminal  22 B of the first conductive member  11   u   1  and the third conductive member  11   u   3  are electrically connected to the common U-phase stator coil  102 . 
     In contrast, the connecting position  11   b  at the other end of the third conductive member  11   u   3  and the first coil connection terminal  22 A are axially laminated on the stator coil  102  of the same phase which is adjacent to the U-phase stator coil  102  on the one circumferential direction side. Further, the first coil connection terminal  22 A is electrically connected to the lead wire  102   a  at one end of the stator coil  102 . 
     The connecting position  11   b  at one end of the fourth conductive member  11   u   4  and the second coil connection terminal  22 B are axially laminated on the U-phase stator coil  102 , to which the first coil connection terminal  22 A at the other end of the second conductive member  11   u   2  is connected. Further, the second coil connection terminal  22 B is electrically connected to the lead wire  102   a  at the other end of the stator coil  102 . In other words, the first coil connection terminal  22 A and the second coil connection terminal  22 B of the second conductive member  11   u   2  and the fourth conductive member  11   u   4  are electrically connected to the common U-phase stator coil  102 . 
     In contrast, the connecting position  11   b  at the other end of the fourth conductive member  11   u   4  and the first coil connection terminal  22 A are axially laminated on the stator coil  102  of the same phase which is adjacent to the U-phase stator coil  102  on the other circumferential direction side. Further, the first coil connection terminal  22 A is electrically connected to the lead wire  102   a  at one end of the stator coil  102 . 
     As illustrated in  FIGS. 5 and 7 , the V-phase bus ring  10   v  has a first conductive member  11   v   1  and a second conductive member  11   v   2  as the power supply side conductive members. The first conductive member  11   v   1  extends along one circumferential direction with respect to the position of the power supply terminal  21   v  of the same phase. The second conductive member  11   v   2  extends along the other circumferential direction with respect to the position of the power supply terminal  21   v . Each of the first conductive member  11   v   1  and the second conductive member  11   v   2  has a connecting position  11   a  with the power supply terminal  21   v  of the same phase at one end, and a connecting position  11   b  with the first coil connection terminal  22 A at the other end. In the first conductive member  11   v   1  and the second conductive member  11   v   2 , coatings  12   v  are provided at the positions except the connecting positions  11   a  and  11   b  at both ends thereof. 
     The connecting positions  11   a  of each of the first conductive member  11   v   1  and the second conductive member  11   v   2  are adjacent to each other in a state of making the axial directions thereof match each other, and extend toward the outer side of the circular ring shape in the radial direction. The first conductive member  11   v   1  and the second conductive member  11   v   2  are integrated by crimping a single power supply terminal  21   v  to each connecting position  11   a  by caulking or the like. Meanwhile, the connecting positions  11   b  of each of the first conductive member  11   v   1  and the second conductive member  11   v   2  are disposed in the vicinity of the adjacent separate V-phase stator coil  102 . In this example, the connecting position  11   b  and the first coil connection terminal  22 A are laminated on the stator coil  102  in the axial direction, and the lead wire  102   a  at one end of the stator coil  102  and the first coil connection terminal  22 A are electrically connected to each other. 
     Further, the bus ring  10   v  has a third conductive member  11   v   3  and a fourth conductive member  11   v   4  as the coupling conductive members. The third conductive member  11   v   3  is arranged in parallel to the first conductive member  11   v   1  along the one circumferential direction. The fourth conductive member  11   v   4  is arranged in parallel to the second conductive member  11   v   2  along the other circumferential direction. The third conductive member  11   v   3  and the fourth conductive member  11   v   4  electrically connect the V-phase stator coils  102  that are adjacent to each other in the circumferential direction. Therefore, in the bus ring  10   v , at least one third conductive member  11   v   3  and at least one fourth conductive member  11   v   4  are provided in accordance with the number of poles. Both ends of each of the third conductive member  11   v   3  and the fourth conductive member  11   v   4  are the connecting positions  11   b  with the coil connection terminal  22 . In the third conductive member  11   v   3  and the fourth conductive member  11   v   4 , the coatings  12   v  are provided at the place except the connecting positions  11   b  at both ends thereof. 
     The bus ring  10   v  includes a single third conductive member  11   v   3  and a single fourth conductive member  11   v   4 . In the bus ring  10   v , the first conductive member  11   v   1  and the third conductive member  11   v   3  are connected to each other, and the second conductive member  11   v   2  and the fourth conductive member  11   v   4  are connected to each other. 
     The connecting position  11   b  at one end of the third conductive member  11   v   3  and the second coil connection terminal  22 B are axially laminated on the V-phase stator coil  102  to which the first coil connection terminal  22 A at the other end of the first conductive member  11   v   1  is connected. Further, the second coil connection terminal  22 B is electrically connected to the lead wire  102   a  at the other end of the stator coil  102 . That is, the first coil connection terminal  22 A and the second coil connection terminal  22 B of the first conductive member  11   v   1  and the third conductive member  11   v   3  are electrically connected to the common V-phase stator coil  102 . 
     In contrast, the connecting position  11   b  at the other end of the third conductive member  11   v   3  and the first coil connection terminal  22 A are axially laminated on the stator coil  102  of the same phase which is adjacent to the V-phase stator coil  102  on the one circumferential direction side. Further, the first coil connection terminal  22 A is electrically connected to the lead wire  102   a  at one end of the stator coil  102 . 
     The connecting position  11   b  at one end of the fourth conductive member  11   v   4  and the second coil connection terminal  22 B are axially laminated on the V-phase stator coil  102 , to which the first coil connection terminal  22 A at the other end of the second conductive member  11   v   2  is connected. Further, the second coil connection terminal  22 B is electrically connected to the lead wire  102   a  at the other end of the stator coil  102 . In other words, the first coil connection terminal  22 A and the second coil connection terminal  22 B of the second conductive member  11   v   2  and the fourth conductive member  11   v   4  are electrically connected to the common V-phase stator coil  102 . 
     In contrast, the connecting position  11   b  at the other end of the fourth conductive member  11   v   4  and the first coil connection terminal  22 A are axially laminated on the stator coil  102  of the same phase which is adjacent to the V-phase stator coil  102  on the other circumferential direction side. Further, the first coil connection terminal  22 A is electrically connected to the lead wire  102   a  at one end of the stator coil  102 . 
     As illustrated in  FIGS. 5 and 8 , the W-phase bus ring  10   w  has a first conductive member  11   w   1  and a second conductive member  11   w   2  as the power supply side conductive members. The first conductive member  11   w   1  extends along one circumferential direction with respect to the position of the power supply terminal  21   w  of the same phase. The second conductive member  11   w   2  extends along the other circumferential direction with respect to the position of the power supply terminal  21   w . Each of the first conductive member  11   w   1  and the second conductive member  11   w   2  has a connecting position  11   a  with the power supply terminal  21   w  of the same phase at one end, and a connecting position  11   b  with the first coil connection terminal  22 A at the other end. In the first conductive member  11   w   1  and the second conductive member  11   w   2 , coatings  12   w  are provided at the places except the connecting positions  11   a  and  11   b  at both ends thereof. 
     The connecting positions  11   a  of each of the first conductive member  11   w   1  and the second conductive member  11   w   2  are adjacent to each other in a state of making the axial directions thereof match each other, and extend toward the outer side of the circular ring shape in the radial direction. The first conductive member  11   w   1  and the second conductive member  11   w   2  are integrated by crimping a single power supply terminal  21   w  to each connecting position  11   a  by caulking or the like. Meanwhile, the connecting positions  11   b  of each of the first conductive member  11   w   1  and the second conductive member  11   w   2  are disposed in the vicinity of the adjacent separate W-phase stator coil  102 . In this example, the connecting position  11   b  and the first coil connection terminal  22 A are laminated on the stator coil  102  in the axial direction, and the lead wire  102   a  at one end of the stator coil  102  and the first coil connection terminal  22 A are electrically connected to each other. 
     Furthermore, the bus ring  10   w  has a third conductive member  11   w   3  and a fourth conductive member  11   w   4  as the coupling conductive members. The third conductive member  11   w   3  is arranged in parallel to the first conductive member  11   w   1  along the one circumferential direction. The fourth conductive member  11   w   4  is arranged in parallel to the second conductive member  11   w   2  along the other circumferential direction. The third conductive member  11   w   3  and the fourth conductive member  11   w   4  electrically connect the W-phase stator coils  102  that are adjacent to each other in the circumferential direction. Therefore, in the bus ring  10   w , at least one third conductive member  11   w   3  and at least one fourth conductive member  11   w   4  are provided in accordance with the number of poles. Both ends of each of the third conductive member  11   w   3  and the fourth conductive member  11   w   4  are the connecting positions  11   b  with the coil connection terminal  22 . In the third conductive member  11   w   3  and the fourth conductive member  11   w   4 , coatings  12   w  are provided at the places except the connecting positions  11   b  at both ends thereof. 
     The bus ring  10   w  includes a single third conductive member  11   w   3  and a single fourth conductive member  11   w   4 . In the bus ring  10   w , the first conductive member  11   w   1  and the third conductive member  11   w   3  are connected to each other, and the second conductive member  11   w   2  and the fourth conductive member  11   w   4  are connected to each other. 
     The connecting position  11   b  at one end of the third conductive member  11   w   3  and the second coil connection terminal  22 B are axially laminated on the W-phase stator coil  102  to which the first coil connection terminal  22 A at the other end of the first conductive member  11   w   1  is connected. Further, the second coil connection terminal  22 B is electrically connected to the lead wire  102   a  at the other end of the stator coil  102 . That is, the first coil connection terminal  22 A and the second coil connection terminal  22 B of the first conductive member  11   w   1  and the third conductive member  11   w   3  are electrically connected to the common W-phase stator coil  102 . 
     In contrast, the connecting position  11   b  at the other end of the third conductive member  11   w   3  and the first coil connection terminal  22 A are axially laminated on the stator coil  102  of the same phase which is adjacent to the W-phase stator coil  102  on the one circumferential direction side. Further, the first coil connection terminal  22 A is electrically connected to the lead wire  102   a  at one end of the stator coil  102 . 
     The connecting position  11   b  at one end of the fourth conductive member  11   w   4  and the second coil connection terminal  22 B are axially laminated on the W-phase stator coil  102 , to which the first coil connection terminal  22 A at the other end of the second conductive member  11   w   2  is connected. Further, the second coil connection terminal  22 B is electrically connected to the lead wire  102   a  at the other end of the stator coil  102 . In other words, the first coil connection terminal  22 A and the second coil connection terminal  22 B of the second conductive member  11   w   2  and the fourth conductive member  11   w   4  are electrically connected to the common W-phase stator coil  102 . 
     In contrast, the connecting position  11   b  at the other end of the fourth conductive member  11   w   4  and the first coil connection terminal  22 A are axially laminated on the stator coil  102  of the same phase which is adjacent to the W-phase stator coil  102  on the other circumferential direction side. Further, the first coil connection terminal  22 A is electrically connected to the lead wire  102   a  at one end of the stator coil  102 . 
     As illustrated in  FIGS. 5 and 9 , the neutral-phase bus ring  10   n  has a first conductive member  11   n   2  and a second conductive member  11   n   2  that are arranged side by side in the circumferential direction. 
     The first conductive member  11   n   1  is electrically connected to the lead wire  102   a  at the other end of the U-phase stator coil  102  (to which the first coil connection terminal  22 A of the U-phase third conductive member  11   u   3  is connected), the lead wire  102   a  at the other end of the V-phase stator coil  102  (to which the first coil connection terminal  22 A of the V-phase third conductive member  11   v   3  is connected), and the lead wire  102   a  at the other end of the W-phase stator coil  102  (to which the first coil connection terminal  22 A of the W-phase third conductive member  11   w   3  is connected). For this reason, the first conductive member  11   n   1  has the connecting positions  11   b  with the second coil connection terminal  22 B provided at both ends and the middle thereof, and the coating  12   n  is provided at a place except the three connecting positions  11   b . The first conductive member  11   n   1  laminates the respective connecting positions  11   b  and the second coil connection terminals  22 B with respect to the stator coils  102  of the respective phases in the axial direction. 
     The second conductive member  11   n   2  is electrically connected to the lead wire  102   a  at the other end of the U-phase stator coil  102  (to which the first coil connection terminal  22 A of the U-phase fourth conductive member  11   u   4  is connected), the lead wire  102   a  at the other end of the V-phase stator coil  102  (to which the first coil connection terminal  22 A of the V-phase fourth conductive member  11   v   4  is connected), and the lead wire  102   a  at the other end of the W-phase stator coil  102  (to which the first coil connection terminal  22 A of the W-phase fourth conductive member  11   w   4  is connected). For this reason, the second conductive member  11   n   2  has the connecting positions  11   b  with the second coil connection terminal  22 B provided at both ends and the middle thereof, and the coating  12   n  is provided at a place except the three connecting positions  11   b . The second conductive member  11   n   2  laminates the respective connecting positions  11   b  and the second coil connection terminals  22 B with respect to the stator coils  102  of the respective phases in the axial direction. 
     In the power supply ring  1 , the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  thus formed are concentrically arranged on the same plane side by side in a radial direction, and the bus rings are bundled together. The power supply ring  1  is provided with a holding member  30  that performs such holding ( FIGS. 1 to 4 and 10 ). The holding member  30  is formed of an insulating material such as synthetic resin, and a plurality of holding members  30  is arranged at intervals in the circumferential direction. 
     The holding member  30  of this example has first to third holding bodies  31 A,  31 B, and  31 C ( FIGS. 11 to 13 ). The first to third holding bodies  31 A,  31 B and  31 C are coupled to be spaced apart from each other in a tangential direction of the annular bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n . The first to third holding bodies  31 A,  31 B, and  31 C have two pieces  32  and  33  disposed along a plane orthogonal to the axis P and spaced apart from each other, and hold the conductive members  11  of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n , while holding the bus rings with the two pieces  32  and  33  from above the coating  12 . The first to third holding bodies  31 A,  31 B, and  31 C are capable of holding a maximum of the four conductive members  11  covered with the coating  12 . Thus, the four holding units  30   a ,  30   b ,  30   c , and  30   d  are formed in the space between the two pieces  32  and  33 . The holding member  30  holds the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  so that the holding unit  30   a  is disposed on the inner side in the radial direction and the holding unit  30   d  is disposed on the outer side in the radial direction. Between the two pieces  32  and  33 , the holding unit  30   a  side on the inner side in the radial direction is an opening. In the holding member  30 , the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  are inserted into the holding units  30   a ,  30   b ,  30   c , and  30   d  from the opening. The first to third holding bodies  31 A,  31 B, and  31 C have elasticity so that the gap between the two pieces  32  and  33  can be expanded with the opposite side of the opening as a fulcrum, upon insertion of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n . Either one of the inserted bus rings  10   u ,  10   v , or  10   w  of each phase is held in each of the holding units  30   a ,  30   b ,  30   c , and  30   d . In the holding member  30  which holds the neutral-phase bus ring  10   n , the neutral-phase bus ring  10   n  is held by the holding unit  30   d.    
     The holding member  30  has an extension portion  34  extending radially outward from the opposite side of the openings of the first to third holding bodies  31 A,  31 B, and  31 C, and an engaging portion  35  is provided in the extension portion  34 , ( FIGS. 1, 11, and 12 ). Meanwhile, the stator  100  is provided with a portion  103   a  to be engaged ( FIG. 1 ). By engaging the engaging portion  35  of the holding member  30  with the portion  103   a  to be engaged, it is possible to position the power supply ring  1  with respect to the stator  100 , and it is possible to fix the power supply ring  1  to the stator  100 . For example, one of the engaging portion  35  and the portion  103   a  to be engaged is a through-hole, and the other thereof is a protrusion fitted to the through-hole. In this example, the engaging portion  35  as a protrusion is formed in the extension portion  34 , and the portion  103   a  to be engaged as a through-hole is provided in the stator  100 . 
     Here, the respective holding members  30  are provided for each stator coil  102 , and are laminated on the respective stator coils  102  in the axial direction. Therefore, the portion  103   a  to be engaged of this example is provided in the coil insulator  103  of the stator coil  102 . For example, the portion  103   a  to be engaged is formed in a piece extending radially outward from the coil insulator  103 . The engaging portion  35  is inserted into the portion  103   a  to be engaged, together with the axial movement in which the power supply ring  1  is placed on the annular body including the plurality of stator coils  102  (the annular stator coil group). Therefore, the engaging portion  35  of this example protrudes toward the moving direction of the power supply ring  1  at the time of placement. 
     Further, since the respective holding members  30  are laminated on the respective stator coils  102  in the axial direction, the holding members  30  are disposed near the coil connection terminals  22  (the first coil connection terminals  22 A and the second coil connection terminals  22 B) connected to the corresponding stator coils  102 . In the holding member  30 , the second coil connection terminal  22 B is disposed in a gap  36  between the first holding body  31 A and the second holding body  31 B, and the first coil connection terminal  22 A is disposed in a gap  37  between the first holding body  31 A and the third holding body  31 C ( FIG. 13 ). 
     Each holding member  30  can suppress a change in the relative position of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  with respect to the stator  100 . Therefore, in the power supply ring  1 , it is possible to suppress an increase in the body size of the stator unit in the axial direction and in the radial direction. 
     As described above, in the power supply ring  1  of the present embodiment, the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  are concentrically laminated on the annular body including a plurality of stator coils  102  (the annular stator coil group) in the axial direction. Therefore, when the power supply ring  1  is attached to the stator  100 , it is possible to suppress an increase in the body size of the stator unit in the radial direction. By disposing the power supply ring  1  so that the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  are placed between the outer wall surface side and the inner wall surface side of the annular body when viewed in the axial direction, it is possible to further suppress an increase in the body size of the stator unit in the radial direction. 
     Furthermore, since the bus rings  10   u ,  10   v , and  10   w  of each phase and the neutral-phase bus ring  10   n  are concentrically arranged side by side in the radial direction in the power supply ring  1 , when attached to the stator  100 , it is possible to suppress an increase in the body size of the stator unit in the axial direction and in the radial direction. 
     Furthermore, in the power supply ring  1 , the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  are provided with connecting positions  11   a  and  11   b  on the same plane as the main body portion extending in the circumferential direction. Further, in the power supply ring  1 , the power supply terminals  21   u ,  21   v , and  21   w  and the coil connection terminals  22  (the first coil connection terminals  22 A and the second coil connection terminals  22 B) are disposed such that the longitudinal direction extends along a plane orthogonal to the axis P. From this fact, it is also possible to suppress an increase in the body size of the stator unit in the axial direction in the power supply ring  1 . 
     Furthermore, in the power supply ring  1 , since the holding member  30  can suppress a change in the relative position of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  with respect to the stator  100 , from this fact, it is possible to suppress an increase in body size of the stator unit in the axial direction and in the radial direction. 
     Furthermore, since the power supply ring  1  uses an ultraviolet cured coating as the coating  12 , the wire diameters of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  can be made thin. In the power supply ring  1 , from that fact, it is also possible to suppress an increase in the body size of the stator unit in the axial direction and in the radial direction. 
     In the stator unit illustrated here, since the power supply ring  1  is laminated on the annular body of the stator coil group, there is a risk of a decrease in the supply amount of the lubricating oil to the stator coil  102  by the power supply ring  1 , leading to degradation of the cooling performance of the stator coil  102 . Therefore, it is desirable that the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  be bundled and held together in a state of being spaced apart from each other in the radial direction. In the power supply ring  1 , the holding member  30  is formed as follows so that the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  are held. For example, in the first to third holding bodies  31 A,  31 B, and  31 C, on the surface of one (here, the piece  33 ) of the two pieces  32  and  33  facing the other (here, the piece  32 ), three protrusions  33   a  protruding toward the other piece (the piece  32 ) are formed ( FIG. 14 ). Each protrusion  33   a  locks the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  inserted into the holding units  30   a ,  30   b ,  30   c , and  30   d  at their positions, and each protrusion  33   a  is formed so that a gap in the radial direction is provided between the adjacent bus rings among the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n . The gap is set to a size within a range which enables the lubricating oil to reach the stator coil  102 . The protrusion  33   a  is set to a protrusion amount within a range in which the insertion of the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  into the holding units  30   a ,  30   b ,  30   c , and  30   d  is not hindered. In this way, in the stator unit of this example, since the lubricating oil can flow from the gap G between the bus rings  10   u ,  10   v , and  10   w  and the neutral-phase bus ring  10   n  to the respective stator coils  102 , it is possible to suppress the degradation of the cooling performance of the stator coil  102 . Therefore, in the power supply ring  1  of the present embodiment, it is possible to suppress an increase in the body size of the stator unit in the axial direction and in the radial direction, while suppressing the degradation of the cooling performance of the stator coil  102 . 
     In the power supply ring according to the present embodiment, since the respective bus rings are concentrically laminated on the annular body made up of a plurality of stator coils in the axial direction, when attached to the stator, it is possible to suppress an increase in the body size of the stator unit in the radial direction. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.