Electric vehicle

Abstract

This electric vehicle (10) comprises a motor (16) that drives a rear wheel (12R), and a bus ring (44) that is attached to a stator core (42A) of the motor (16). The bus ring (44) comprises a plurality of first fastening parts (701) and a plurality of second fastening parts (702). The plurality of first fastening parts (701) fasten the bus ring (44) together with the stator core (42A) to a motor housing part (36) of a swing arm (14). The plurality of second fastening parts (702) fasten a control device (24) to the bus ring (44).

Description

Electric vehicles

[0001] The present invention relates to an electric vehicle.

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have become more active, and research and development into electrification technologies has been conducted to reduce CO2 emissions and improve energy efficiency in vehicles. International Publication No. 2021 / 199165 discloses an electric vehicle in which a motor is disposed laterally of the rear wheels and drives the rear wheels. In the electric vehicle, the motor is attached together with a reduction gear to a case of a swing arm that is swingably mounted relative to the vehicle body. The rear wheel is rotatably supported on the rear end of the swing arm, laterally in the vehicle width direction of the swing arm.

[0003] International Publication No. 2021 / 065451 discloses a motor having a control device disposed at one axial end of a rotating shaft. The control device is accommodated inside a housing constituting the motor and fixed to the housing via a substrate. The control device controls the drive of the motor.

[0004] However, when an electrically-integrated motor with a control device disposed at one axial end of the motor, as in WO 2021 / 065451, is installed in the electric vehicle of WO 2021 / 199165, there is a problem in that vibrations during driving of the electric vehicle are transmitted from the rear wheels to the control device, reducing durability. Solving this problem will contribute to improving energy efficiency.

[0005] The present invention aims to solve the above-mentioned problems.

[0006] One aspect of the present invention is an electric vehicle comprising: a body frame; a pivot shaft provided on the body frame; a swing arm having one end journaled on the pivot shaft and the other end supporting a rear wheel; a motor disposed inside the swing arm for driving the rear wheel; and a control device disposed axially of the motor for controlling the drive of the motor. The motor comprises a stator including a stator core around which a coil is wound; and a bus ring attached to one axial side of the stator core and to which the coil is connected, and the bus ring comprises a plurality of first fastening portions that fasten the bus ring together with the stator core to a motor accommodating portion of the swing arm, and a plurality of second fastening portions that fasten the control device to the bus ring.

[0007] According to the present invention, in an electric vehicle, a bus ring is fixed to the motor housing portion of the swing arm together with the stator core, and by attaching a control device to the bus ring, the control device can be firmly fixed via the bus ring, thereby effectively suppressing vibration of the control device while the electric vehicle is running.

[0008] FIG. 1 is a side view of an electric vehicle according to an embodiment of the present invention. FIG. 2 is an explanatory plan view of the rear end of the electric vehicle. FIG. 3 is an explanatory side view showing the rear end of a swing arm in the electric vehicle of FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is an external perspective view of a bus ring. FIG. 6 is a plan view of the bus ring shown in FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 3. FIG. 8 is an exploded perspective view of a motor, bus ring, and control device.

[0009] As shown in Figure 1, the electric vehicle 10 according to this embodiment is an electric scooter, and the rear wheel 12R is driven to rotate by the driving force of a motor 16 built into a swing arm 14 that supports the rear wheel 12R. Note that the electric vehicle 10 is not limited to an electric scooter. For example, it may be any electric straddle-type vehicle that is driven by the motor 16. In the following explanation, a scooter-type electric vehicle 10 will be described.

[0010] The electric vehicle 10 includes a body frame 18, a body cover 20 that covers the body frame 18, a drive unit 22 that includes a motor 16 that drives the rear wheel 12R, and a control device 24 (see FIG. 3) that controls the drive of the drive unit 22. The body frame 18 includes a head pipe 181 at the front end, a down pipe 182 that extends diagonally downward and rearward from the head pipe 181, an underframe portion 183 that extends rearward from the rear end of the down pipe 182, and side frame portions 184 that extend diagonally upward and rearward from the rear end of the underframe portion 183. The head pipe 181 supports front forks 26 that extend diagonally downward and forward. The tips of the front forks 26 support the front wheel 12F.

[0011] The body frame 18 includes a pivot shaft 28. The pivot shaft 28 is provided on the side frame portion 184 and extends in the left-right direction (vehicle width direction) of the electric vehicle 10. The pivot shaft 28 supports the swing arm 14.

[0012] The swing arm 14 extends in the front-to-rear direction of the electric vehicle 10. The swing arm 14 incorporates a drive unit 22 such that the drive unit 22 is disposed to the side of the rear wheel 12R. One end 14F of the swing arm 14 is disposed in the front of the electric vehicle 10. The one end 14F of the swing arm 14 (hereinafter also referred to as the front end 14F) is rotatably supported on the body frame 18 via a pivot shaft 28. The other end 14R of the swing arm 14 (hereinafter referred to as the rear end 14R) is disposed in the rear of the electric vehicle 10. The rear end 14R of the swing arm 14 is disposed to the left of the rear wheel 12R and rotatably supports the rear wheel 12R. As shown in FIG. 2 , the rear wheel 12R is supported by the rear end 14R of the swing arm 14 such that the central axis of the rear wheel 12R is aligned with the vehicle width direction of the electric vehicle 10.

[0013] 1, a rear suspension 30 is provided between the rear end 14R of the swing arm 14 and the side frame portion 184. The upper end of the rear suspension 30 is connected to the side frame portion 184, and the lower end of the rear suspension 30 is connected to the rear end 14R of the swing arm 14.

[0014] As shown in FIG. 2 , the swing arm 14 includes a case 32 and a cover portion 34. The case 32 extends along the front-to-rear direction of the electric vehicle 10. A front end portion 14F of the case 32 is supported by the pivot shaft 28. The case 32 includes a motor housing portion 36 that opens outward in the vehicle width direction of the body frame 18. The motor housing portion 36 is provided at the rear end portion 14R of the case 32 and houses the drive unit 22. The motor housing portion 36 has a housing space 38 (see FIG. 3 ) that can house the drive unit 22. That is, the motor housing portion 36 opens to one side in the vehicle width direction. The one side in the vehicle width direction is the outward side in the vehicle width direction, which is the direction opposite the rear wheel 12R.

[0015] As shown in Fig. 3, the motor 16 includes a rotor 40, a stator 42 surrounding the rotor 40, and an annular bus ring 44. The motor 16 is disposed such that the axial direction of the stator 42 is parallel to the central axis of the rear wheel 12R. As shown in Fig. 2, the motor 16 is disposed to the side of the rear wheel 12R in the direction of the central axis of the rear wheel 12R. The central axis of the rear wheel 12R is in the vehicle width direction of the electric vehicle 10. Note that the motor 16 is not limited to an electric motor mounted on the electric vehicle 10 as an electric motor. For example, the motor 16 may be used as both an electric motor and a generator. The motor 16 may also be a generator.

[0016] The rotor 40 has a rotor body 401 and a rotating shaft 402. A plurality of magnets (not shown) are provided on the outer periphery of the rotor body 401. The rotating shaft 402 is press-fitted into the center of the rotor body 401 along the axial direction of the rotor body 401. This connects the rotor body 401 and the rotating shaft 402 and allows them to rotate integrally.

[0017] The stator 42 includes a stator core 42A, a plurality of insulators 43, and a plurality of coils 46 wound around each of the insulators 43. The stator 42 is fixed to the case 32 of the swing arm 14 along the axial direction of the stator 42. The stator core 42A includes an annular portion 421. The stator core 42A is formed by stacking a plurality of steel plates (not shown) in the axial direction. The annular portion 421 has a plurality of mounting holes 48 that penetrate the steel plates in the thickness direction (see FIG. 4). The mounting holes 48 are arranged spaced apart from one another in the circumferential direction of the annular portion 421 (see FIG. 8). The insulator 43 is provided on the inner periphery of the annular portion 421. The insulator 43 includes a winding portion 431 around which the coil 46 is wound.

[0018] As shown in FIG. 4 , the stator core 42A further includes a first axial end face 501 provided on one axial side of the stator 42 and a second axial end face 502 provided on the other axial side of the stator 42. When the drive unit 22 including the stator 42 is housed in the motor housing portion 36, the first axial end face 501 faces the bottom surface of the motor housing portion 36 in the axial direction, and the second axial end face 502 faces the cover portion 34 and the control device 24 (see FIG. 2 ). The second axial end face 502 is a surface provided on the opposite side of the stator core 42A from the first axial end face 501 in the axial direction. The first axial end face 501 is supported by an annular support portion 361 provided in the motor housing portion 36. A case fastening hole 362 is formed in the support portion 361.

[0019] As shown in Fig. 5, bus ring 44 is formed into an annular shape from a resin material. Bus ring 44 is provided to connect a plurality of coils 46 (see Fig. 4). Bus ring 44 is provided at one axial end of stator core 42A (see Fig. 4).

[0020] The bus ring 44 has an annular ring portion 52. As shown in FIG. 4 , the ring portion 52 includes a first end surface 541, a second end surface 542, an inner ring portion 56, and an outer ring portion 58.

[0021] First end surface 541 is a surface provided on ring portion 52 and facing stator core 42A. First end surface 541 abuts against second axial end surface 502 of stator core 42A. Second end surface 542 is a surface provided on ring portion 52 and on the opposite side of first end surface 541 in the axial direction of bus ring 44.

[0022] As shown in FIG. 6 , the inner ring portion 56 includes three bus bars 60. Each bus bar 60 is a conductor made of a metal material and is connected to a respective one of the three-phase (U-phase, V-phase, and W-phase) coils 46. The multiple bus bars 60 are provided on the second end surface 542 of the inner ring portion 56. Each of the multiple bus bars 60 includes a main body portion 621, a terminal portion 622 provided on the main body portion 621 and connected to the coil 46, and a connection portion 623 to which a power line (not shown) is connected. As shown in FIG. 5 , the terminal portion 622 protrudes in the axial direction from one axial end of the main body portion 621 of the bus bar 60. An end of the coil 46 is connected to the terminal portion 622 (see FIG. 3 ). The connection portion 623 extends in the axial direction from the axial end of the main body portion 621 and then bends radially outward. The connection portion 623 protrudes radially outward beyond the inner ring portion 56.

[0023] The outer ring portion 58 is disposed radially outward of the inner ring portion 56. The outer ring portion 58 includes a plurality of recesses 64 and a plurality of protrusions 66. As shown in FIG. 4 , the plurality of recesses 64 are recessed from a second end surface 542 of the outer ring portion 58 toward the stator core 42A. As shown in FIG. 6 , the plurality of recesses 64 extend radially from the outer periphery of the outer ring portion 58 toward the inner ring portion 56. The plurality of recesses 64 are spaced apart from one another in the circumferential direction of the ring portion 52.

[0024] As shown in Fig. 5, the multiple protrusions 66 each protrude from the second end surface 542 of the outer ring portion 58 in a direction away from the stator core 42A. The multiple protrusions 66 are spaced apart from one another in the circumferential direction of the ring portion 52. As shown in Fig. 6, the multiple protrusions 66 and the multiple recesses 64 are alternately arranged in the circumferential direction of the ring portion 52.

[0025] The second end surface 542 further includes an inner end surface 68 provided on the inner ring portion 56. As shown in Figure 7, in the axial direction of the bus ring 44, the multiple protrusions 66 protrude further in a direction away from the stator core 42A than the inner end surface 68.

[0026] As shown in FIG. 5 , the bus ring 44 further includes a plurality of first fastening portions 701 and a plurality of second fastening portions 702 .

[0027] As shown in Fig. 4, the plurality of first fastening portions 701 fasten the bus ring 44 together with the stator core 42A to the motor accommodating portion 36 of the swing arm 14. As shown in Fig. 6, the plurality of first fastening portions 701 are respectively provided on the outer ring portion 58. The plurality of first fastening portions 701 are respectively provided on the plurality of recesses 64. Note that the plurality of first fastening portions 701 are not limited to being respectively provided on the plurality of recesses 64. For example, the plurality of first fastening portions 701 may be directly provided on the second end surface 542, which does not have a recess.

[0028] Each of the first fastening portions 701 has a plurality of first fastening holes 721. As shown in FIG. 4 , each of the first fastening holes 721 penetrates the bus ring 44 in the axial direction. A first insert member 711 is provided in each of the first fastening holes 721. The first insert member 711 is formed from a metal material in a cylindrical shape and fitted into the first fastening hole 721. A stator fastening member 74 is inserted into the first insert member 711. With the stator fastening member 74 inserted into the first fastening hole 721 of the bus ring 44 and the mounting hole 48 of the stator core 42A, the stator fastening member 74 is fastened to the case fastening hole 362 formed in the motor accommodating portion 36. Note that the stator fastening member 74 may be inserted directly into the first fastening hole 721 without providing the first insert member 711.

[0029] As shown in FIG. 7 , the plurality of second fastening portions 702 fasten the control device 24 to the bus ring 44. As shown in FIG. 6 , the plurality of second fastening portions 702 are provided on the outer ring portion 58, respectively. The plurality of second fastening portions 702 are provided on the plurality of protruding portions 66, respectively. As shown in FIG. 7 , the plurality of second fastening portions 702 each have a plurality of second fastening holes 722. Each of the second fastening holes 722 penetrates the bus ring 44 in the axial direction. Note that the plurality of second fastening portions 702 are not limited to being provided on the plurality of protruding portions 66, respectively. For example, the plurality of second fastening portions 702 may be provided directly on the second end face 542, which does not have any protruding portions.

[0030] A plurality of second insert members 712 are provided in the plurality of second fastening holes 722. The second insert members 712 are formed from a metal material into a cylindrical shape and fitted into the second fastening holes 722. The board fastening members 82 are inserted into the second insert members 712 and fastened. Alternatively, the board fastening members 82 may be inserted directly into the second fastening holes 722 and fastened without providing the second insert members 712.

[0031] As shown in FIG. 6 , the multiple second fastening portions 702 have multiple co-tightening portions 76. The multiple co-tightening portions 76 are connected to the connection portions 623 of the multiple bus bars 60, respectively. The multiple co-tightening portions 76 are arranged at equal intervals from one another in the circumferential direction of the bus ring 44. Among the multiple second fastening portions 702, the multiple co-tightening portions 76 are arranged every other one in the circumferential direction of the bus ring 44. Note that the multiple co-tightening portions 76 do not have to be arranged at equal intervals in the circumferential direction of the bus ring 44. For example, the multiple co-tightening portions 76 may be arranged adjacent to one another in the circumferential direction of the bus ring 44.

[0032] When viewed from the axial direction of the stator core 42A, the multiple first fastening portions 701 and the multiple second fastening portions 702 are arranged on the same circumference. The multiple first fastening portions 701 and the multiple second fastening portions 702 are arranged alternately in the circumferential direction of the ring portion 52. The number of first fastening portions 701 is the same as the number of second fastening portions 702. Note that the number of first fastening portions 701 and the number of second fastening portions 702 may be different. The multiple first fastening portions 701 and the multiple second fastening portions 702 may be arranged on circumferences of circles with different diameters.

[0033] As shown in Fig. 3, the control device 24 is provided in the motor housing portion 36 of the swing arm 14. In the motor housing portion 36, the control device 24 is arranged in the axial direction of the motor 16 (see Fig. 2). As shown in Fig. 7, the control device 24 is arranged on the opposite side of the bus ring 44 from the stator core 42A. That is, the multiple protrusions 66 of the bus ring 44 protrude from the second end surface 542 of the ring portion 52 toward the control device 24.

[0034] As shown in FIG. 8 , the control device 24 includes a substrate 78 and a plurality of electrical components 80 provided on the substrate 78. The substrate 78 is formed in a disk shape and faces the second end surface 542 of the bus ring 44 (see FIG. 4 ). The outer edge of the substrate 78 has a plurality of holes 781 through which substrate fastening members 82 are inserted. The plurality of substrate fastening members 82 are inserted into the plurality of holes 781, respectively. The plurality of substrate fastening members 82 are fastened to second fastening holes 722 of the bus ring 44. As shown in FIG. 7 , at this time, the connection portions 623 of the plurality of bus bars 60 are sandwiched between the plurality of co-fastening portions 76 and the substrate 78. The plurality of connection portions 623 and the substrate 78 are electrically connected to each other.

[0035] Next, the operation of the drive unit 22 in the electric vehicle 10 will be described. When a driver (not shown) opens a throttle provided on the handle of the electric vehicle 10, current is applied to the bus ring 44 of the motor 16 from a power source (not shown) via the control device 24, and the coil 46 is excited to generate a rotating magnetic field, which drives the rotor 40 to rotate inside the stator 42. The rotational force (driving force) of the rotor 40 is reduced in speed by a reducer (not shown) and then transmitted to the rear wheel 12R. The electric vehicle 10 moves as the rear wheel 12R is driven.

[0036] This embodiment has the following advantages.

[0037] 3 , electric vehicle 10 includes swing arm 14, motor 16 disposed in motor housing portion 36 of swing arm 14, and bus ring 44 to which coil 46 of stator 42 of motor 16 is connected. Bus ring 44 includes a plurality of first fastening portions 701 that fasten bus ring 44 together with stator core 42A of motor 16 to motor housing portion 36 of swing arm 14, and a plurality of second fastening portions 702 that fasten control device 24 to bus ring 44.

[0038] According to this electric vehicle 10, bus ring 44 is fixed to motor housing portion 36 of swing arm 14 together with stator core 42A, and by attaching control device 24 to this bus ring 44, control device 24 can be firmly fixed to stator 42 via bus ring 44. Therefore, vibration of control device 24 when electric vehicle 10 is traveling can be effectively suppressed.

[0039] As shown in Fig. 2, the axial direction of stator core 42A is arranged parallel to the central axis direction of rear wheel 12R. As shown in Fig. 4, bus ring 44 has an annular ring portion 52, a first end face 541 provided on ring portion 52 facing stator core 42A, a second end face 542 provided on the opposite side from first end face 541, and a plurality of recesses 64 recessed from second end face 542 of ring portion 52 toward stator core 42A. A plurality of first fastening portions 701 are provided in the plurality of recesses 64, respectively.

[0040] Thus, by providing the first fastening portion 701 in the recess 64 of the second end face 542, the dimension of the electric vehicle 10 in the vehicle width direction (the direction of the central axis of the rear wheel 12R) can be reduced.

[0041] 4, control device 24 is disposed on the opposite side of bus ring 44 from stator core 42A, and bus ring 44 includes a plurality of bus bars 60 (see FIG. 6) that are connected to the plurality of coils 46, respectively, on second end surface 542 of ring portion 52. Bus ring 44 has a plurality of protrusions 66 that protrude from second end surface 542 of ring portion 52 toward control device 24, and a plurality of second fastening portions 702 are provided on the plurality of protrusions 66, respectively.

[0042] This allows the connection portions 623 of the multiple bus bars 60 to be effectively fastened together by the protrusions 66 protruding toward the control device 24 while avoiding the multiple bus bars 60 provided on the second end surface 542 of the ring portion 52.

[0043] As shown in Fig. 6 , the ring portion 52 has an inner ring portion 56 on which a plurality of bus bars 60 are provided, and an outer ring portion 58 disposed radially outward of the inner ring portion 56. As shown in Fig. 7 , the protrusion 66 is provided on the outer ring portion 58 and protrudes beyond an inner end surface 68 of the second end surface 542 of the inner ring portion 56 in the axial direction of the bus ring 44.

[0044] This makes it easy to connect the connection portions 623 of the multiple bus bars 60 to the protrusions 66. When the control device 24 is fastened to the second fastening portion 702 via the connection portions 623, contact between the control device 24 and portions of each bus bar 60 other than the connection portions 623 provided on the inner end surfaces 68 is effectively prevented.

[0045] The second fastening portions 702 each have a plurality of co-fastening portions 76 to which the bus bars 60 are respectively connected. The co-fastening portions 76 are arranged at equal intervals from one another in the circumferential direction of the bus ring 44.

[0046] This allows the connection portions 623 of multiple bus bars 60 to be evenly attached to the second fastening portion 702 in the circumferential direction of the bus ring 44, thereby effectively distributing the load when fastening the connection portions 623 to the bus ring 44.

[0047] 2, the motor 16 is disposed to the side of the rear wheel 12R in the direction of the central axis of the rear wheel 12R. This allows the dimension of the electric vehicle 10 in the vehicle width direction (in the direction of the central axis of the rear wheel 12R) to be shortened, thereby preventing the rear wheel 12R from protruding outward in the vehicle width direction at the side. When the electric vehicle 10 is banked in the vehicle width direction while traveling, with the ground contact points of the front wheel 12F and the rear wheel 12R as fulcrums, contact between the swing arm 14 including the motor 16 and the road surface can be effectively prevented.

[0048] 6, when viewed in the axial direction of the stator core 42A, the first fastening portions 701 and the second fastening portions 702 are arranged on the same circumference. This makes it possible to effectively suppress radial outward expansion of the motor 16 compared to a configuration in which the first fastening portions 701 and the second fastening portions 702 are arranged on different circumferences.

[0049] In addition to the above disclosure, the following additional notes are disclosed.

[0050] (Supplementary Note 1) An electric vehicle (10) comprises a body frame (18), a pivot shaft (28) provided on the body frame, a swing arm (14) having one end (14F) journaled on the pivot shaft and the other end (14R) supporting a rear wheel (12R), a motor (16) disposed inside the swing arm and driving the rear wheel, and a control device (24) disposed axially of the motor and controlling the drive of the motor, the motor comprising a stator (42) including a stator core (42A) around which a coil (46) is wound, and a bus ring (44) attached to one axial side of the stator core and to which the coil is connected, the bus ring comprising a plurality of first fastening portions (701) for fastening the bus ring together with the stator core to a motor accommodating portion (36) of the swing arm, and a plurality of second fastening portions (702) for fastening the control device to the bus ring.

[0051] With this configuration, the bus ring is fixed to the motor housing portion of the swing arm together with the stator core, and the control device is attached to the bus ring, so that the control device can be firmly fixed via the bus ring, effectively suppressing vibration of the control device when the electric vehicle is running.

[0052] (Supplementary Note 2) In the electric vehicle described in Supplementary Note 1, the axial direction of the stator core and the central axis of the rear wheel may be arranged parallel to each other, and the bus ring may have an annular ring portion (52), a first end face (541) provided on the ring portion facing the stator core, a second end face (542) provided on the ring portion opposite the first end face in the axial direction of the bus ring, and a plurality of recesses (64) recessed from the second end face of the ring portion toward the stator core, and a plurality of the first fastening portions may be provided in the plurality of recesses. With this configuration, by providing the first fastening portions in the recesses of the second end face, it is possible to reduce the dimension of the electric vehicle in the vehicle width direction.

[0053] (Supplementary Note 3) In the electric vehicle described in Supplementary Note 1, the bus ring may have an annular ring portion, a first end face provided on the ring portion facing the stator core, and a second end face provided on the ring portion and opposite the first end face in the axial direction of the bus ring, the control device may be disposed on the opposite side of the bus ring from the stator core, the bus ring may include a plurality of bus bars (60) connected to the plurality of coils on the second end face of the ring portion, the bus ring may have a plurality of protrusions (66) protruding from the second end face of the ring portion toward the control device, and the plurality of second fastening portions may be provided on the plurality of protrusions, respectively. With this configuration, the connection portions of the plurality of bus bars can be effectively fastened by the protrusions protruding toward the control device while avoiding the plurality of bus bars provided on the second end face of the ring portion.

[0054] (Supplementary Note 4) In the electric vehicle described in Supplementary Note 3, the ring portion may have an inner ring portion (56) on which the plurality of bus bars are provided and an outer ring portion (58) disposed radially outward of the inner ring portion, the second end surface may have an inner end surface (68) provided on the inner ring portion, and the convex portion may be provided on the outer ring portion, and the convex portion may protrude beyond the inner end surface of the inner ring portion in the axial direction of the bus ring. This configuration makes it easy to connect the connection portions of the plurality of bus bars to the convex portion. When a control device is fastened to the second fastening portion via the connection portions, contact between the control device and portions of the plurality of bus bars other than the connection portions provided on the inner end surfaces is effectively prevented.

[0055] (Supplementary Note 5) In the electric vehicle described in Supplementary Note 1, the second fastening portions may include a plurality of co-fastening portions (76) to which a plurality of bus bars are respectively connected, and the co-fastening portions may be arranged at equal intervals from one another in a circumferential direction of the bus ring. With this configuration, by attaching the connection portions of the plurality of bus bars to the second fastening portions evenly in the circumferential direction of the bus ring, it is possible to effectively distribute the load when fastening the connection portions to the bus ring.

[0056] (Supplementary Note 6) In the electric vehicle described in Supplementary Note 2, the motor may be disposed to the side of the rear wheel in the direction of the central axis of the rear wheel. With this configuration, the dimension of the electric vehicle in the vehicle width direction can be shortened, and outward protrusion in the vehicle width direction at the side of the rear wheel can be suppressed. When the electric vehicle is tilted in the vehicle width direction while traveling, contact between the swing arm including the motor and the road surface can be effectively suppressed.

[0057] (Supplementary Note 7) In the electric vehicle described in Supplementary Note 1, the first fastening portions and the second fastening portions may be arranged on the same circumference as viewed in the axial direction of the stator core. With this configuration, radial outward expansion of the motor can be more effectively suppressed than in a configuration in which the first fastening portions and the second fastening portions are arranged on different circumferences.

[0058] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention.

[0059] 10... Electric vehicle 12R... Rear wheel 14... Swing arm 16... Motor 18... Body frame 24... Control device 28... Pivot shaft 32... Case 34... Cover portion 36... Motor accommodating portion 42... Stator 42A... Stator core 44... Bus ring 46... Coil 701... First fastening portion 702... Second fastening portion

Claims

1. An electric vehicle (10) comprising: a body frame (18); a pivot shaft (28) provided on the body frame (18); a swing arm (14) having one end (14F) journaled on the pivot shaft (28) and the other end (14R) supporting a rear wheel (12R); a motor (16) disposed inside the swing arm (14) for driving the rear wheel (12R); and a control device (24) disposed axially of the motor (16) for controlling the drive of the motor (16), wherein the motor (16) comprises: a stator (42) including a stator core (42A) around which a coil (46) is wound; and a bus ring (44) attached to one axial side of the stator core (42A) and to which the coil (46) is connected, and the bus ring (44) comprises: an electric vehicle (10) including: a plurality of first fastening portions (701) that fasten the bus ring (44) together with the stator core (42A) to a motor accommodating portion (36) of the swing arm (14); and a plurality of second fastening portions (702) that fasten the control device (24) to the bus ring (44).

2. An electric vehicle (10) according to claim 1, wherein the axial direction of the stator core (42A) and the central axis direction of the rear wheel (12R) are arranged parallel to each other, and the bus ring (44) has an annular ring portion (52), a first end face (541) provided on the ring portion (52) and facing the stator core (42A), a second end face (542) provided on the ring portion (52) and provided on the opposite side of the first end face (541) in the axial direction of the bus ring (44), and a plurality of recesses (64) recessed from the second end face (542) of the ring portion (52) toward the stator core (42A), and a plurality of first fastening portions (701) are provided in the plurality of recesses (64), respectively.

3. In the electric vehicle (10) according to claim 1, the bus ring (44) has an annular ring portion (52), a first end face (541) provided on the ring portion (52) facing the stator core (42A), and a second end face (542) provided on the ring portion (52) and opposite the first end face (541) in the axial direction of the bus ring (44), the control device (24) is disposed on the bus ring (44) opposite the stator core (42A), and the bus ring (44) has a plurality of bus bars (60) connected to the second end face (542) of the ring portion (52) respectively with the plurality of coils (46), the bus ring (44) has a plurality of protrusions (66) protruding from the second end surface (542) of the ring portion (52) toward the control device (24), and a plurality of the second fastening portions (702) are provided on the plurality of protrusions (66), respectively.

4. An electric vehicle (10) according to claim 3, wherein the ring portion (52) has an inner ring portion (56) on which a plurality of the bus bars (60) are provided, and an outer ring portion (58) arranged radially outward of the inner ring portion (56), the second end face (542) has an inner end face (68) provided on the inner ring portion (56), the convex portion (66) is provided on the outer ring portion (58), and the convex portion (66) protrudes beyond the inner end face (68) of the inner ring portion (56) in the axial direction of the bus ring (44).

5. An electric vehicle (10) according to claim 1, wherein the plurality of second fastening portions (702) have a plurality of co-fastening portions (76) to which a plurality of bus bars (60) are respectively connected, and the plurality of co-fastening portions (76) are arranged at equal intervals from one another in the circumferential direction of the bus ring (44).

6. An electric vehicle (10) according to claim 2, wherein the motor (16) is disposed to the side of the rear wheel (12R) in the direction of the central axis of the rear wheel (12R).

7. An electric vehicle (10) as described in claim 1, wherein, when viewed in the axial direction of the stator core (42A), a plurality of the first fastening portions (701) and a plurality of the second fastening portions (702) are arranged on the same circumference.

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