Patent Publication Number: US-2022216753-A1

Title: Rotor for rotary electric machine and rotary electric machine

Description:
TECHNICAL FIELD 
     The present invention relates to a stator for a rotary electric machine. 
     BACKGROUND ART 
     As a background art in the present technical field, the following conventional art is disclosed. PTL 1 (JP 2017-184375 A) describes a rotor for a rotary electric machine including: a rotor core; and a magnet housing hole which penetrates along an axial direction Z of the rotor core and in which a permanent magnet is housed, wherein a pair of non-magnetic plates are fixed each on one of both end faces of the rotor core, a pair of magnet fixing pieces sandwiching narrow-width side surfaces of the permanent magnet are extended to enter the magnet housing hole from a part of the plate corresponding to the magnet housing hole. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP 2017-184375 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     A magnet insertion hole provided in a rotor core of a rotary electric machine is formed larger than a permanent magnet inserted therein, and the magnet moves in the magnet insertion hole due to rotational motion or vibration of the rotor; therefore, there is a problem that the magnet is brought into contact with the magnet insertion wall by the movement and becomes worn. In order to suppress such movement of the magnet, the permanent magnet is fixed to the magnet insertion hole with an adhesive. In addition, in PTL 1, a pair of magnet fixing pieces sandwiching the narrow-width side surfaces of the permanent magnet are provided. 
     However, when an adhesive is used to fix the permanent magnet, a configuration for applying the adhesive is required, and the number of steps increases. In addition, a step of removing an excessive adhesive protruding from the rotor is required. In addition, the attachment position of the magnet in the magnet insertion hole varies, and a performance of the rotary electric machine is deteriorated. Further, it is difficult to remove the magnet after assembly, so that it is difficult to recycle the rotary electric machine at the time of disposal. In the rotor for the rotary electric machine described in PTL 1, parts of the plate are formed into the magnet fixing pieces, and ease of assembly is accordingly low. Further, a stator core cannot be configured with a plurality of divided core pieces. 
     Solution to Problem 
     An example of a typical example of the invention disclosed in the present application is as follows. Specifically, a rotor for a rotary electric machine has the following features. The rotary shaft includes: a rotary shaft; at least one magnet; a rotor core having at least one magnet housing inside which the at least one magnet is attached; and at least one fixing member disposed inside the at least one magnet housing to fix the at least one magnet, wherein the at least one fixing member includes: a first fixing portion that is in contact with a side surface of the at least one magnet in a radial direction of the rotary shaft or in contact with a side surface of the at least one magnet in a circumferential direction of the rotary shaft; and a second fixing portion that is in contact with an end face of the at least one magnet in an axial direction of the rotary shaft. The first fixing portion and the second fixing portion are connected to each other at an angle smaller than 90 degrees, and the at least one fixing member is inserted, together with the at least one magnet, in the at least one magnet housing and presses the at least one magnet against an inner wall of the at least one magnet housing due to an increase in the angle between the first fixing portion and the second fixing portion. 
     Advantageous Effects of Invention 
     An aspect of the present invention makes it possible to firmly fix the magnet at a predetermined position of the magnet insertion portion. The following description of embodiments will clarify problems, configurations, and effects other than those described above. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic configuration view of a hybrid electric vehicle equipped with a rotary electric machine according to an embodiment of the present invention. 
         FIG. 2  is a schematic diagram illustrating an overall configuration of a rotary electric machine. 
         FIG. 3  is a cross-sectional view taken along line A-A of  FIG. 2 . 
         FIG. 4  is an exploded perspective view of a rotor. 
         FIG. 5  is a partial cross-sectional view of a stator core before a permanent magnet is inserted into a magnet insertion hole. 
         FIG. 6  is a partial cross-sectional view of the stator core in a state where the permanent magnet is inserted in the magnet insertion hole. 
         FIG. 7  is a partial cross-sectional view of the stator core in a state where the permanent magnet is inserted in the magnet insertion hole. 
         FIG. 8  is a view of a state in which a fixing member is attached to a side surface of a permanent magnet in a radial direction (side surface extending in a circumferential direction) as viewed from an axial direction. 
         FIG. 9  is a view of a state in which a fixing member is attached to a side surface of a permanent magnet in the circumferential direction (side surface extending in the radial direction) as viewed from the axial direction. 
         FIG. 10  is a perspective view of a stator core configured with two core pieces. 
         FIG. 11  is a partial cross-sectional view of a stator core configured with two core pieces. 
         FIG. 12  is a partial cross-sectional view of a stator core configured with two core pieces. 
         FIG. 13  is a partial cross-sectional view of a stator core configured with three core pieces. 
         FIG. 14  is a partial cross-sectional view of a stator core configured with three core pieces. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments will be described with reference to the drawings. 
     As illustrated in  FIG. 1 , a vehicle  100  of a hybrid vehicle is mounted with an engine  120 , a first rotary electric machine  200 , a second rotary electric machine  201 , and a high-voltage battery  150 . The battery  150  is configured with a secondary battery such as a lithium-ion battery or a nickel-metal-hydride battery, and outputs high voltage DC power of 250 volts to 600 volts or higher. The battery  150  supplies DC power to the rotary electric machines  200  and  201  when driving force by the rotary electric machines  200  and  201  is required, and the battery  150  is supplied with DC power from the rotary electrical machines  200  and  201  during regenerative running. The DC power is supplied and received between the battery  150  and the rotary electric machines  200  and  201  via a power convertor  160 . 
     Although not illustrated, the vehicle  100  is equipped with a battery that supplies low-voltage power (for example, 14-volt system power). Rotational torque generated by the engine  120  and the rotary electric machines  200  and  201  is transmitted to front wheels  110  via a transmission  130  and a differential gear  140 . The rotary electric machines  200  and  201  have substantially the same configuration, and the rotary electric machine  200  will be representatively described below. 
       FIG. 2  is a schematic diagram illustrating an overall configuration of the rotary electric machine  200 .  FIG. 2  is a partial cross-sectional view of the rotary electric machine  200 , and illustrates the inside of the rotary electric machine  200 . 
     As illustrated in  FIG. 2 , a stator  300  is supported inside a housing  205 , and the stator  300  includes a stator core  305  and a stator coil  510 . A rotor  400  is rotatably supported in the inner peripheral side of the stator core  305  via an air gap  500 . The rotor  400  has a rotor core  405  fixed to a shaft  430 , a permanent magnet  415 , and end plates  420  of a non-magnetic material. The housing  205  has a pair of end brackets  210  on which bearings  425  and  426  are provided, and the shaft  430  is rotatably supported by the bearings  425  and  426 . The end plates  420  are fixed to the shaft  430  by press fitting, shrink fitting, or the like. 
     The rotary electric machine  200  is a three-phase synchronous motor with built-in permanent magnets. The rotary electric machine  200  operates as an electric motor in which the rotor  400  is rotated by a current of a three-phase alternating current supplied to the stator coil  510  wound around the stator core  305 . In addition, when driven by the engine  120 , the rotary electric machine  200  operates as a generator and outputs generated three-phase alternating current power. That is, the rotary electric machine  200  has both of the following two functions: a function as an electric motor that generates rotational torque using electric energy; and a function as a generator that generates electric power using mechanical energy, and the above-described functions can be selectively used depending on a running condition of the vehicle. 
       FIG. 3  is a diagram illustrating an A-A cross-section (see  FIG. 2 ) of the stator  300  and the rotor  400  shown in  FIG. 2 , and  FIG. 4  is an exploded perspective view of the rotor  400  of the present embodiment. In  FIG. 3 , the housing  205  and the shaft  430  are not shown. 
     The stator core  305  is formed in such a manner that by laminating a plurality of magnetic bodies (for example, a plurality of electromagnetic steel sheets) are stacked in the axial direction, and is configured with a yoke portion and a teeth portion (also referred to as projections and salient pole portions). The yoke portion is configured with a cylindrical yoke core  306  (also referred to as a core back) fitted to the inner peripheral side of the housing  205 . The teeth portion protrudes in the radial direction from the inner peripheral side of the yoke core  306 , and is configured with a plurality of teeth cores  307  arranged in the circumferential direction at predetermined intervals. In  FIG. 3 , not all the teeth are denoted by reference signs, but only some of the teeth cores  307  are representatively denoted by reference numerals. A plurality of slots  310  are formed, continuously in the circumferential direction, on the rotor  400  side between respective ones of the neighboring teeth cores  307 . In the slots  310 , slot insulations (not shown) using a slot liner are provided, and winding wires of a plurality of phases such as a U-phase, a V-phase, and a W-phase constituting the stator  300  are mounted. In the present embodiment, the stator coil  510  (see  FIG. 2 ) is wound by distributed winding. 
     On the other hand, the rotor core  405  is formed of a plurality of magnetic bodies, for example, a plurality of electromagnetic steel sheets stacked in the axial direction, and the electromagnetic steel plates have magnet insertion holes  410  into which magnets are inserted. The magnet insertion holes  410  are formed at equal intervals in the circumferential direction in the vicinity of an outer peripheral part of the rotor core  405 , and a magnet is embedded in each magnet insertion hole. Magnet insertion holes  410  are formed such that a width and thickness of each magnet insertion hole  410  are larger than the width and thickness of the permanent magnet  415 . Therefore, an air gap is formed between a surface of each permanent magnet  415  and an inner wall of the corresponding magnet insertion hole  410  to improve ease of insertion of the permanent magnets  415  at the time of assembly. The permanent magnets  415  acts as field poles of the rotor  400 . 
     The magnet insertion holes  410  are larger than the length dimensions (dimension in a stacking direction) of the permanent magnets  415  in consideration of accumulated dimensional tolerance of components in the stacking direction of the rotor core  405 , and gaps are formed between permanent magnets  415  and each end plate  420 . 
     As described above, since an air gap is provided between each permanent magnet  415  and the corresponding magnet insertion hole  410  in each of the radial direction, the circumferential direction, and the axial direction, the permanent magnet  415  may come into contact with the inner wall of the magnet insertion hole  410  and could become worn due to movement of the permanent magnet  415  in the magnet insertion hole  410  due to rotation or vibration of the rotor  400 . The wear of the permanent magnet  415  causes deterioration of characteristics of the rotary electric machine  200 . Therefore, in the present embodiment, a fixing member  440  made of a thin plate is disposed in the gap between each permanent magnet  415  and the rotor core  405  to fill the gap and thus to hold each permanent magnet  415 , thereby suppressing the movement of each permanent magnet  415 . 
     The magnetization direction of each permanent magnet  415  is directed in the radial direction, and the direction of the magnetization direction is reversed for each field pole. Specifically, when stator side surfaces of the permanent magnets  415   a  are the N-pole and surfaces on a shaft side are the S-pole, the stator side surfaces of the adjacent permanent magnets  415   b  are the S-pole and the surfaces on the shaft side are the N-pole. These permanent magnets  415   a  and  415   b  are alternately arranged in the circumferential direction. The permanent magnets  415  may be embedded in the rotor core  405  after being magnetized, or may be inserted into the rotor core  405  before being magnetized and then be magnetized by applying a strong magnetic field. The permanent magnets  415  after magnetization are strong magnets, and when the magnets are magnetized before the permanent magnets  415  are fixed to the rotor  400 , strong attractive force is generated between the permanent magnets  415  and the rotor core  405  at the time of fixing the permanent magnets  415 , and this attractive force hiders the work. In addition, the strong attractive force might cause dust such as iron powder to adhere to the permanent magnets  415 . Therefore, when the permanent magnets  415  are magnetized after being inserted into the rotor core  405 , productivity of the rotary electric machine is improved. 
     As the permanent magnets  415 , there can be used neodymium-based magnets, samarium-based sintered magnets, ferrite magnets, neodymium-based bonded magnets, or the like. The permanent magnets  415  each have a residual magnetic flux density of approximately 0.4 to 1.3 T. 
       FIGS. 5 to 9  are diagrams illustrating how the permanent magnet  415  and the fixing member  440  are disposed in the magnet insertion hole  410 .  FIG. 5  illustrates a partial cross-section of the rotor core  405  before a permanent magnet  415  is inserted into the magnet insertion hole  410 ,  FIGS. 6 and 7  each illustrate a partial cross-section of the rotor core  405  in a state where the permanent magnet  415  is inserted in the magnet insertion hole  410 ,  FIG. 8  illustrates a view in which a fixing member  440  is attached to a radial side surface (side surface extending in the circumferential direction) of a permanent magnet  415  as viewed from the axial direction, and  FIG. 9  illustrates a view in which a fixing member  440  is attached to the circumferential side surface (side surface extending in the radial direction) of a permanent magnet  415  as viewed from the axial direction. 
     The fixing member  440  is a member that is formed substantially in an L-shape and is disposed to fill gaps between the permanent magnet  415  and the rotor core  405  and between the permanent magnet  415  and the end plate  420 . Specifically, the fixing member  440  is configured with a first fixing portion  440 A of a thin plate member disposed between the permanent magnet  415  and the rotor core  405  and with a second fixing portion  440 B of a thin plate member disposed between the permanent magnet  415  and the end plate  420 , and the first fixing portion  440 A and the second fixing portion  440 B are connected to each other substantially in an L-shape at an acute angle (specifically, an angle smaller than 90°). The fixing member  440  may be configured of any of a non-magnetic material, a magnetic material, and a synthetic resin. In addition, as illustrated in  FIGS. 8 and 9 , a length of a side surface of the fixing member  440  in contact with the permanent magnet  415  (a width L 3  of the first fixing portion  440 A) is preferably made smaller than a width M 1  of the side surface of the permanent magnet  415  which is one of the following two side surfaces: the side surface in the axial direction (the side surface extending in the circumferential direction); and the side surface on the circumferential direction (the side surface extending in the axial direction) and on which the fixing member  440  is disposed (in other words, which is the side surface of the permanent magnet  415  in the radial direction in  FIG. 8  and the side surface of the permanent magnet  415  in the circumferential direction in  FIG. 9 ), so that the fixing member  440  does not protrude from the width of the permanent magnet  415  and there is therefore a margin at the time of insertion of the fixing member  440  and the permanent magnet  415  into the magnet insertion hole  410 , whereby workability is improved. 
     The permanent magnet  415  is inserted into the magnet insertion hole  410  as illustrated in  FIG. 6 , with the fixing member  440  being disposed such that the first fixing portion  440 A extends along the side surface of the permanent magnet  415  and the second fixing portion  440 B is in contact with a bottom surface (surface on the insertion side in the axial direction) of the permanent magnet  415  as illustrated in  FIG. 5 . The length L 1  of the first fixing portion  440 A is preferably longer than the length L 2  of the second fixing portion  440 B. 
     In addition, as illustrated in  FIG. 7 , after the fixing member  440  is inserted to a position at which the fixing member is in contact with the end plate  420 , the fixing member  440  is further pushed, so that the L-shaped angle is widened to generate a repulsive force. As a result, there are generated the following two forces: a force by which the first fixing portion  440 A presses the permanent magnet  415  against the inner wall of the magnet insertion hole  410 ; and a force by which the second fixing portion  440 B presses the permanent magnet  415  in the axial direction, so that the permanent magnet  415  is fixed at a predetermined position in the magnet insertion hole  410  by the interaction of the two forces. 
     In this case, as illustrated in  FIGS. 8 and 9 , a thickness T 1  of the fixing member  440  is preferably set to be smaller than a value obtained by subtracting a size M 2  from a size L 4  so that there is a margin at the time of the insertion of the permanent magnet  415  to which the fixing member  440  is attached into the magnet insertion hole  410 , whereby workability is therefore improved. The above size M 2  is a size of the permanent magnet  415  on the side which is in either the radial direction or the circumferential direction and on which fixing member  440  is not disposed (a side surface of the permanent magnet  415  in the circumferential direction in  FIG. 8 , or a side surface of the permanent magnet  415  in the radial direction in  FIG. 9 ). The above size L 4  is a size of the magnet insertion hole  410  on the side which is in either the radial direction or the circumferential direction and on which the fixing member  440  is not disposed. 
     As illustrated in  FIG. 8 , of the side surfaces of the permanent magnet  415 , the fixing member  440  may be disposed on the side surface in the radial direction. As illustrated in  FIG. 9 , of the side surfaces of the permanent magnet  415 , the permanent magnet  415  may be disposed on the side surface in the circumferential direction. Regardless of which surface the fixing member  440  is disposed on, the fixing member  440  is further pushed in from the position where the fixing member  440  is in contact with the end plate  420 , so that the L-shape is widened, and a force for holding the permanent magnet  415  in the axial direction is generated by friction between the permanent magnet  415  and the rotor core  405  (the inner wall of the magnet insertion hole  410 ), whereby the permanent magnet  415  is fixed at a predetermined position in the magnet insertion hole  410 . 
       FIGS. 10 to 14  are diagrams each illustrating an example in which the rotor core  405  is configured with a plurality of core pieces.  FIG. 10  is a perspective view of the rotor core  405  configured with two core pieces,  FIGS. 11 and 12  each illustrate a partial cross-section of the rotor core  405  configured with two core pieces, and  FIGS. 13 and 14  each illustrate a partial cross-section of the rotor core  405  configured with three core pieces. 
     The rotor core  405  may be configured with one core piece as illustrated in  FIG. 4 , or may be configured with two core pieces  405 A and  405 B as illustrated in  FIG. 10 . By configuring the rotor core  405  with a plurality of core pieces, it is possible to reduce an iron loss due to an eddy current generated in the magnet. As illustrated in  FIG. 10 , the plurality of core pieces may be disposed at shifted positions. 
     When the rotor core  405  is configured with two core pieces, as illustrated in  FIG. 11 , the permanent magnets  415  are attached to the magnet insertion hole  410  of the rotor core  405 , one for each of the core pieces  405 A and  405 B. The permanent magnets  415  are fixed to the rotor core  405  such that fixing members  440  are each disposed along one of the permanent magnets  415 . Alternatively, as illustrated in  FIG. 12 , the fixing members  440  may be disposed alternately along the opposite side surfaces of the permanent magnets  415 . 
     In addition to the illustrated forms, the fixing members  440  may be disposed alternately on the surfaces in the circumferential direction of the permanent magnets  415 . With this arrangement, the permanent magnets  415  are arranged to be shifted to each other in the circumferential direction; therefore, it is possible to reduce the torque ripple in the same manner as the skew. 
     Alternatively, the fixing members  440  may be disposed alternatively on the surfaces in the circumferential direction and the surfaces in the radial direction of the permanent magnets  415 . With this arrangement, the permanent magnets  415  are arranged to be shifted; therefore, it is possible to reduce the cogging. 
     Further, the rotor core  405  may be configured with three core pieces. In this case, as illustrated in  FIG. 13 , in the magnet insertion hole  410  of the rotor core  405 , the permanent magnet  415  is attached to each core piece. The permanent magnets  415  are fixed to the rotor core  405  such that fixing members  440  are each disposed along one of the permanent magnets  415 . further, as illustrated in  FIG. 14 , the fixing members  440  may be disposed alternately along different surfaces of the permanent magnets  415 . 
     As described above, according to an embodiment of the present invention, a rotor  400  of a rotary electric machine is characterized in that the rotary shaft includes: a rotary shaft (shaft  430 ); at least one magnet (permanent magnet  415 ); a rotor core  405  having at least one magnet housing (magnet insertion hole  410 ) inside which the at least one magnet  415  is attached; and at least one fixing member  440  disposed inside the at least one magnet housing  410  to fix the at least one magnet  415 , wherein the at least one fixing member  440  includes: a first fixing portion  440 A that is in contact with a side surface of the at least one magnet  415  in a radial direction of the rotary shaft or in contact with a side surface of the at least one magnet  415  in a circumferential direction of the rotary shaft; and a second fixing portion  440 B that is in contact with an end face of the at least one magnet  415  in an axial direction of the rotary shaft. The first fixing portion  440 A and the second fixing portion  440 B are connected to each other at an angle smaller than 90 degrees, and the at least one fixing member  440  is inserted, together with the at least one magnet  415 , in the at least one magnet housing  410  and presses the at least one magnet  415  against an inner wall of the at least one magnet housing  410  due to an increase in the angle between the first fixing portion  440 A and the second fixing portion  440 B, so that it is possible to firmly fix the at least one magnet  415  to a predetermined position inside the magnet insertion hole  410  without sacrificing the ease of assembly. In addition, there is no leakage or protrusion unlike a liquid adhesive, and it is therefore easy to manage the manufacturing process. In addition, since the bent part of the fixing member  440  (the part connecting the first fixing portion  440 A and the second fixing portion  440 B) has an acute angle, the bent part functions as a guide when the magnet  415  is attached to the stator core  405 , whereby the ease of assembly can be improved. 
     In addition, since the length L 1  of the first fixing portion  440 A is equal to or longer than the length L 2  of the second fixing portion  440 B, the fixing member  440  can appropriately press the magnet  415 . 
     In the case where the fixing member  440  is in contact with the side surface of the magnet  415  in the radial direction, the width L 3  of the first fixing portion  440 A in the circumferential direction is equal to or less than the length M 1  of the magnet  415  in the circumferential direction. In the case where the fixing member  440  is in contact with the side surface of the magnet  415  in the circumferential direction, the width L 3  of the first fixing portion  440 A in the radial direction is equal to or less than the length M 1  of the magnet  415  in the radial direction. Therefore, the fixing member  440  does not protrude from the magnet  415  in the width direction, and the ease of assembly can be improved. 
     In the case where the fixing member  440  is in contact with the side surface of the magnet  415  in the radial direction, the thickness T 1  of the first fixing portion  440 A is smaller than the value obtained by subtracting the length M 2  of the magnet  415  in the circumferential direction from the length L 4  of the magnet housing  410  in the circumferential direction. In the case where the fixing member  440  is in contact with the side surface of the magnet  415  in the circumferential direction, the thickness T 1  of the first fixing portion  440 A is smaller than the value obtained by subtracting the length M 2  of the magnet  415  in the radial direction from the length L 4  of the magnet housing  410  in the radial direction. Therefore, the magnet  415  and the fixing member  440  can be easily inserted into the magnet insertion hole  410 , and the ease of assembly can be improved. 
     The fixing member  440  is formed of any of a non-magnetic material, a magnetic material, and a resin material. When a non-magnetic material is used to form the fixing member  440 , it is possible to use a material such as stainless steel having high corrosion resistance without disturbing the magnetic force by the magnet  415 . Further, when a magnetic material is used to form the fixing member  440 , the fixing member  440  can act integrally with the magnet  415 . Alternatively, when the fixing member  440  is formed of a resin material, it is possible to reduce the weight and cost. In addition, because the fixing member  440  has an insulation property, an eddy current can be reduced. 
     In addition, a plurality of magnets  415  are attached inside one magnet housing  410 , and the fixing members  440  are each arranged in a pair with one of the single magnets  415  so as to fix each of the plurality of magnets attached inside the magnet  415  housing, so that the plurality of magnets  415  can be each firmly fixed at a predetermined position inside the magnet insertion hole  410 . 
     In addition, the rotor core  405  is configured with a plurality of core pieces  405 A and  405 B forming the magnet housing  410 , and the plurality of core pieces  405 A and  405 B are stacked to constitute the rotor core  405  such that attachment positions of the magnets  415  are shifted in the circumferential direction, so that the magnets  415  provided for each core piece can be firmly fixed at predetermined positions inside the magnet insertion hole  410 . 
     In addition, regarding the plurality of magnets  415  attached to one magnet housing  410 , the fixing members  440  are disposed at such positions that the fixing members  440  are in contact with the surfaces, of the magnets  415 , in different directions, so that the magnets  415  are arranged in the rotor core  405  to be shifted from the center of the magnet insertion hole  410 , whereby a torque ripple can be reduced. 
     Further, regarding the magnets  415  adjacently attached to one magnet housing, the fixing members  440  are disposed at such positions that the fixing members  440  are in contact with the opposite side surfaces of the magnets  415 , so that the magnets  415  are arranged in the rotor core  405  to be shifted from the center of the magnet insertion hole  410 , whereby a torque ripple can be reduced. 
     Note that the present invention is not limited to the above-described embodiments, and includes various variations and equivalent configurations within the spirit of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to an embodiment including all the described configurations. Further, a part of the configuration of one embodiment may be replaced with a configuration of another embodiment. In addition, a configuration of another embodiment may be added to the configuration of one embodiment. In addition, another configuration may be added to, removed from, or substituted for a part of the configuration of each embodiment. 
     REFERENCE SIGNS LIST 
     
         
           100  vehicle 
           110  front wheel 
           120  engine 
           130  transmission 
           140  differential gear 
           150  battery 
           160  power convertor 
           200 ,  201  second rotary electric machine 
           205  housing 
           210  end bracket 
           300  stator 
           305  stator core 
           306  yoke core 
           307  Teeth core 
           310  slot 
           400  rotor 
           405  rotor core 
           405 A,  405 B core piece 
           410  magnet insertion hole 
           415 ,  415   a ,  415   b  permanent magnet 
           420  end plate 
           425 ,  426  bearing 
           430  shaft 
           440  fixing member 
           440 A first fixing portion 
           440 B second fixing portion 
           500  air gap 
           510  stator coil