Motor and electric vehicle

Abstract

A motor (10) comprises a fixed part (300), a rotating part (100), and a rim part (400). The rotating part (100) rotates with respect to the fixed part (300). The rim part (400) supports a tire. The rotating part (100) is provided with: a yoke (110) that has a cylindrical yoke body part (113) and a yoke side contact part (114) which is provided outward of the yoke body part (113) in the radial direction (RD); and a magnet (120) that is attached to the yoke body part (113). The rim part (400) is provided with a rim side contact part (411) that contacts the outside of the yoke side contact part (114) in the radial direction (RD). The length of the yoke side contact part (114) in the axial direction (AD) and the length of the yoke body part (411) in the axial direction (AD) differ, or the position of the center of the yoke side contact part (114) in the axial direction (AD) and the position of the center of the yoke body part (113) in the axial direction (AD) differ. [Selected drawing] FIG. 4

Description

Motors and electric vehicles

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

[0002] Wheels for saddle-riding electric vehicles have been known (see, for example, Patent Document 1). Wheels for saddle-riding electric vehicles include a rim that supports a tire, a hub that is located inward of the rim of the wheel, and a back yoke that is located inward of the hub and supports a ferrite magnet. In the wheel described in Patent Document 1, the axial center of the rim, the axial center of the hub, and the axial center of the back yoke are all located at the same position.

[0003] JP 2013-126859 A

[0004] In the wheel described in Patent Document 1, when the axial position of the rim is shifted to accommodate a brake mechanism or the like, the yoke does not have a structure, such as a back yoke, for contacting the rim, so the axial lengths of the hub and yoke must also be increased, which results in a heavy yoke.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a motor and an electric vehicle that can reduce the weight of the yoke without increasing its size.

[0006] An exemplary motor according to the present disclosure includes a fixed portion, a rotating portion, and a rim portion. The rotating portion rotates relative to the fixed portion. The rim portion supports a tire. The rotating portion includes a yoke including a cylindrical yoke main body portion and a yoke-side contact portion provided radially outward of the yoke main body portion, and a magnet attached to the yoke main body portion. The rim portion includes a rim-side contact portion that contacts the radially outer side of the yoke-side contact portion. The axial length of the yoke-side contact portion is different from the axial length of the yoke main body portion, or the position of the axial center of the yoke-side contact portion is different from the position of the axial center of the yoke main body portion.

[0007] An exemplary electric vehicle according to the present disclosure includes the motor described above and a wheel, the motor being attached to the wheel.

[0008] According to an exemplary embodiment of the present disclosure, the yoke has a yoke-side contact portion on the yoke body that corresponds to the position of the rim portion relative to the yoke, which results in a reduction in the weight of the yoke without increasing its size.

[0009] FIG. 1 is a perspective view showing a motor according to a first embodiment of the present disclosure. FIG. 2 is an exploded view showing the interior of the motor according to the first embodiment. FIG. 3 is a cross-sectional view showing the configuration of the motor according to the first embodiment. FIG. 4 is an enlarged cross-sectional view showing the configuration of the motor according to the first embodiment. FIG. 5 is a schematic diagram of an electric motorcycle including the motor according to the first embodiment. FIG. 6 is an enlarged cross-sectional view showing the configuration of a motor according to a second embodiment of the present disclosure. FIG. 7 is an enlarged cross-sectional view showing the configuration of a motor according to a third embodiment of the present disclosure. FIG. 8 is an enlarged cross-sectional view showing the configuration of a motor according to a fourth embodiment of the present disclosure.

[0010] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0011] For convenience, the present specification may refer to the direction of the motor's central axis AX (see FIG. 1 ) as the horizontal direction. In the drawings, the X-, Y-, and Z-axes of a three-dimensional Cartesian coordinate system are appropriately indicated for ease of understanding. In one example, the positive direction of the Z-axis indicates the upward direction, and the negative direction of the Z-axis indicates the downward direction. However, the up-down direction, the upward direction, and the downward direction are defined for convenience of explanation and do not necessarily correspond to the vertical direction. Furthermore, the definition of the up-down direction is given merely for convenience of explanation and does not limit the orientation of the motor according to the present invention during use or assembly. Furthermore, the direction parallel to the motor's central axis AX will be referred to simply as the "axial direction AD," and the radial and circumferential directions centered on the motor's central axis AX will be referred to simply as the "radial direction RD" and the "circumferential direction CD." Note that, in this specification, "parallel direction" also includes directions that are approximately parallel.

[0012] In this specification, the central axis AX of the motor may coincide with the central axis of the rotor, but the central axis AX of the motor does not have to coincide with the central axis of the rotor. If the central axis AX of the motor does not coincide with the central axis of the rotor, the rotor may rotate around a virtual central axis different from the central axis AX of the motor.

[0013] In this specification, the direction along the central axis AX of the motor or the central axis of the rotor may be referred to as the axial direction. Therefore, in this specification, the axial direction refers to the direction along the central axis AX that is the rotation center of the motor or the central axis that is the rotation center of the rotor.

[0014] First Embodiment First, a motor 10 according to a first embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a perspective view showing the motor 10 according to the first embodiment of the present disclosure. As shown in Fig. 1, the motor 10 includes a rotor 100, a fixed portion 300, and a rim portion 400. The rotor 100 is an example of a "rotating portion."

[0015] The motor 10 is attached to a wheel of a four-wheeled vehicle or a two-wheeled vehicle, for example. Typically, the motor 10 is used as an in-wheel motor attached to the axle of a four-wheeled vehicle or a two-wheeled vehicle.

[0016] The rim portion 400 supports a tire (not shown) and is fixed to the outer side of the rotor 100 in the radial direction RD.

[0017] Next, a motor 10 according to a first embodiment will be described with reference to Figures 1 and 2. Figure 2 is an exploded view showing the interior of the motor 10 according to the first embodiment. As shown in Figures 1 and 2, the fixed part 300 includes a shaft 50, a motor stator 200, and a stator holder 250.

[0018] The shaft 50 is a substantially cylindrical body. The shaft 50 is disposed about a central axis AX extending along an axial direction AD. In the case of an in-wheel motor, the shaft 50 is a fixed shaft and constitutes an axle.

[0019] The motor stator 200 is a substantially cylindrical body. The motor stator 200 is located radially outward from the shaft 50 in the radial direction RD. Specifically, the motor stator 200 is disposed about a central axis AX extending along the axial direction AD. The motor stator 200 is fixed to the shaft 50. The motor stator 200 is also located radially inward from the rotor 100.

[0020] The rotor 100 is a substantially cylindrical body. The rotor 100 is located radially outward from the fixed part 300 in the RD direction. Specifically, the rotor 100 is disposed around a central axis AX extending along the axial direction AD. The rotor 100 surrounds the fixed part 300 on the radially outward side in the RD direction. The rotor 100 rotates around the central axis AX relative to the shaft 50. Such a rotor 100 is also called an outer rotor.

[0021] The motor stator 200 includes a stator core 210 , an insulator 220 , a coil 230 , and an insulating plate 240 .

[0022] Stator core 210 is disposed about a central axis AX extending in the axial direction AD. As an example, stator core 210 has a generally annular shape centered on central axis AX. "Regular annular" means, for example, "generally circular annular." Stator core 210 is formed, for example, from laminated steel plates in which thin electromagnetic steel plates are stacked in the axial direction AD.

[0023] The stator core 210 has a core back and a plurality of teeth. Each of the plurality of teeth extends radially outward from the radially outer surface of the core back in the radial direction RD. The plurality of teeth are arranged at equal intervals along the circumferential direction CD.

[0024] The insulator 220 covers at least a portion of the stator core 210. As an example, the insulator 220 surrounds the stator core 210 from both sides in the axial direction AD. The insulator 220 is generally annular. "Regularly annular" means, for example, "approximately circular ring shape." The insulator 220 is an electrical insulator. The insulator 220 electrically insulates the stator core 210 from the coil 230. The insulator 220 may be formed of a single member, or may be formed of multiple separate members. For example, the insulator 220 is a resin molded product into which the stator core 210 is inserted. Furthermore, the insulator 220 may be configured to be separately attached to the stator core 210.

[0025] The coil 230 is wound around the stator core 210 via the insulator 220. The coil 230 is a coated conductor in which a metal wire is coated with a coating. The material of the metal wire is, for example, copper. However, the material of the metal wire may be aluminum instead of copper. The coating that coats the metal wire is, for example, an insulating resin.

[0026] The stator holder 250 is a disk body having a through-hole at its center that penetrates along the axial direction AD. The motor stator 200 is disposed at the outer end of the stator holder 250 in the radial direction RD. For example, the shaft 50 is press-fitted into the through-hole, and the shaft 50 and the stator holder 250 are fixed together. At this time, the shaft 50 is exposed to the outside of the stator holder 250. The shaft 50 extends from the stator holder 250 along the central axis AX to one side in the axial direction AD (+X direction). The shaft 50 also extends from the stator holder 250 along the central axis AX to the other side in the axial direction AD (-X direction).

[0027] The insulating plate 240 is formed of, for example, an insulating resin. The insulating plate 240 is disposed between the stator holder 250 and the motor stator 200. The insulating plate 240 is a substantially cylindrical body. Note that the insulating plate 240 and the insulator 220 may be formed integrally.

[0028] The rotor 100 includes a yoke 110 and a magnet 120. The magnet 120 is, for example, a permanent magnet. The magnet 120 faces the motor stator 200 on the outside in the radial direction RD. For example, the rotor 100 may have a single, generally annular magnet 120, or may have multiple magnets 120 arranged in the circumferential direction CD. "Regularly annular" means, for example, "approximately circular ring-shaped." The multiple magnets 120 are arranged with alternating north and south poles in the circumferential direction CD. For example, the number of poles of the magnet 120 is "60." However, the number of poles of the magnet 120 is not limited to this.

[0029] The yoke 110 is a substantially cylindrical body. The yoke 110 is, for example, an iron member. The magnet 120 is attached to the yoke 110. Specifically, the yoke 110 is fixed to the outer surface of the magnet 120 in the radial direction RD. The magnet 120 may also be disposed inside the yoke 110.

[0030] Next, a motor 10 according to a first embodiment will be described with reference to FIGS. 1 to 4. FIG. 3 is a cross-sectional view showing the configuration of the motor 10 according to the first embodiment. FIG. 4 is an enlarged cross-sectional view showing the configuration of the motor 10 according to the first embodiment. Note that FIGS. 3 and 4 are cross-sectional views taken along a line connecting the second cover screw holes 112. As shown in FIGS. 1 to 4, the rim portion 400 is fixed to the outer side of the rotor 100 in the radial direction RD.

[0031] The rim portion 400 is an annular member that surrounds the outer periphery of the rotor 100. A tire is attached to the rim portion 400. For example, the material of the rim portion 400 is iron or aluminum, and is preferably the same material as the material of the yoke 110.

[0032] Specifically, the rim portion 400 includes a first cylindrical portion 411, a second cylindrical portion 412, a third cylindrical portion 413, a fourth cylindrical portion 414, a fifth cylindrical portion 415, a first connecting portion 431, a second connecting portion 432, a third connecting portion 433, and a fourth connecting portion 434. The first cylindrical portion 411 is an example of a "rim side contact portion." The second cylindrical portion 412, the third cylindrical portion 413, the fourth cylindrical portion 414, the fifth cylindrical portion 415, the first connecting portion 431, the second connecting portion 432, the third connecting portion 433, and the fourth connecting portion 434 are each an example of a "rim flange portion." In the axial direction AD, the length of the first cylindrical portion 411 is a first distance L1.

[0033] The second cylindrical portion 412 is connected to the other axial direction AD side (−X direction) of the first cylindrical portion 411 via a first connecting portion 431. The third cylindrical portion 413 is connected to the other axial direction AD side (−X direction) of the second cylindrical portion 412 via a second connecting portion 432. The fourth cylindrical portion 414 is connected to one axial direction AD side (X direction) of the first cylindrical portion 411 via a third connecting portion 433. The fifth cylindrical portion 415 is connected to one axial direction AD side (X direction) of the fourth cylindrical portion 414 via a fourth connecting portion 434.

[0034] Specifically, the rim portion 400 protrudes in the radial direction RD from both ends of the first cylindrical portion 411 in the axial direction AD. The rim portion 400 increases in size from the center of the rim portion 400 in the axial direction AD toward one side in the axial direction AD, and also increases in size from the center of the rim portion 400 in the axial direction AD toward the other side in the axial direction AD. The diameter of the second cylindrical portion 412 is larger than the diameter of the first cylindrical portion 411. The diameter of the third cylindrical portion 413 is larger than the diameter of the second cylindrical portion 412. The diameter of the fourth cylindrical portion 414 is larger than the diameter of the first cylindrical portion 411. The diameter of the fifth cylindrical portion 415 is larger than the diameter of the fourth cylindrical portion 414.

[0035] Additionally, the radially outer surface of the yoke 110 in the radial direction RD comes into contact with the radially inner surface of the first cylindrical portion 411. Specifically, the radially inner surface of the first cylindrical portion 411 and the radially outer surface of the yoke 110 in the radial direction RD are press-fitted and welded together.

[0036] The entire radially inner surface of the first cylindrical portion 411 may be in contact with the radially outer surface of the yoke 110, or a portion of the radially inner surface of the first cylindrical portion 411 may be in contact with the radially outer surface of the yoke 110. For example, a central portion of the first cylindrical portion 411 in the axial direction AD may protrude outward in the radial direction RD, and both ends of the first cylindrical portion 411 in the axial direction AD may be in contact with the radially outer surface of the yoke 110.

[0037] When the tire is attached to the rim portion 400, the end of the tire on the other axial direction AD side (−X direction) comes into contact with the radial direction RD outer surface of the second cylindrical portion 412 and the one axial direction AD side of the second connecting portion 432. In addition, the end of the tire on the one axial direction AD side (X direction) comes into contact with the radial direction RD outer surface of the fourth cylindrical portion 414 and the other axial direction AD side (−X direction) of the fourth connecting portion 434.

[0038] The yoke 110 includes a yoke main body 113 and a yoke-side contact portion 114. The yoke main body 113 and the yoke-side contact portion 114 are a single member. As a result, there is no need to fasten the yoke main body 113 and the yoke-side contact portion 114 together by welding or the like, and the yoke 110 is more resistant to impacts from the rim portion 400 than if separate components were fastened together.

[0039] The shape of the yoke main body 113 is cylindrical. The length of the yoke main body 113 in the axial direction AD is a second distance L2.

[0040] The yoke body 113 includes a first cover screw hole 111 and a second cover screw hole 112. Each of the first cover screw hole 111 and the second cover screw hole 112 extends along the axial direction AD.

[0041] The first cover screw holes 111 are provided on the other side surface in the axial direction AD of the yoke main body 113. For example, eight first cover screw holes 111 are formed in the yoke main body 113. The eight first cover screw holes 111 are arranged at equal intervals along the circumferential direction CD.

[0042] The second cover screw holes 112 are provided on one side surface in the axial direction AD of the yoke main body 113. For example, eight second cover screw holes 112 are formed in the yoke 110. The eight second cover screw holes 112 are arranged at equal intervals along the circumferential direction CD. The first cover screw holes 111 and the second cover screw holes 112 are arranged alternately along the circumferential direction CD.

[0043] The yoke side contact portion 114 is provided on the radially outer side of the yoke main body 113 in the radial direction RD. More specifically, the yoke side contact portion 114 is provided on the yoke main body 113 of the yoke 110 in accordance with the position of the rim portion 400 relative to the yoke 110. For example, the shape of the yoke side contact portion 114 is a cylinder provided on the radially outer side of the yoke main body 113 in the radial direction RD. In the axial direction AD, the length of the yoke side contact portion 114 is a third distance L3.

[0044] The yoke side contact portion 114 according to the first embodiment includes a protruding portion 114a and a connecting portion 114b.

[0045] The protruding portion 114a protrudes from the yoke main body 113 to one side in the axial direction AD. The protruding portion 114a has a cylindrical shape. In the axial direction AD, the length of the protruding portion 114a is a fourth distance L4.

[0046] The connecting portion 114b is connected to the outer side of the yoke main body 113 in the radial direction RD. The connecting portion 114b is cylindrical. In the axial direction AD, the length of the connecting portion 114b is a fifth distance L5. The protrusion 114a is disposed on one side surface of the connecting portion 114b in the axial direction AD. The end face of the yoke side contact portion 114 in the axial direction AD is connected to the outer peripheral surface of the yoke main body 113. Specifically, the other side surface of the connecting portion 114b in the axial direction AD is connected to the outer peripheral surface of the yoke main body 113. In other words, a stepped shape is formed on the outer peripheral surface of the yoke 110. As a result, the weight of the yoke can be reduced compared to when the outer peripheral surface of the yoke 110 is a flat surface.

[0047] The length L5 of the connecting portion 114b in the axial direction AD is longer than the length L4 of the protruding portion 114a in the axial direction AD. In other words, the area where the connecting portion 114b is connected to the outer side of the yoke main body 113 in the radial direction RD can be increased. As a result, the yoke main body 113 can be made more resistant to impacts from the rim portion 400.

[0048] In the yoke 110, the length L3 in the axial direction AD of the yoke side contact portion 114 is different from the length L2 in the axial direction AD of the yoke main body 113, or the position of the center of the axial direction AD of the yoke side contact portion 114 is different from the position of the center of the axial direction AD of the yoke main body 113. Specifically, in the yoke 110 according to the first embodiment, the length L3 in the axial direction AD of the yoke side contact portion 114 is different from the length L2 in the axial direction AD of the yoke main body 113, and the position of the center of the axial direction AD of the yoke side contact portion 114 is different from the position of the center of the axial direction AD of the yoke main body 113.

[0049] As described above, according to the first embodiment, for example, the position in the axial direction AD or the length L1 of the first cylindrical portion 411 differs from the position in the axial direction AD or the length L2 of the yoke main body 113, but the yoke 110 is provided with the yoke-side contact portion 114. In other words, the yoke 110 is provided with the yoke-side contact portion 114 corresponding to the position or length L1 of the first cylindrical portion 411 relative to the yoke 110. As a result, the yoke 110 can be made lighter without being larger than a cylindrical yoke.

[0050] Furthermore, since the shape of the yoke side contact portion 114 is cylindrical and located radially outside the yoke main body portion 113 in the radial direction RD, the yoke side contact portion 114 and the rim portion 400 are connected around the entire circumference in the circumferential direction CD, thereby further improving the fixing strength between the yoke 110 and the rim portion 400.

[0051] Specifically, the length L3 in the axial direction AD of the yoke side contact portion 114 is equal to or greater than half the length L1 in the axial direction AD of the first cylindrical portion 411. As a result, it is possible to suppress deformation of the first cylindrical portion 411. The length L2 in the axial direction AD of the yoke side contact portion 114 according to the first embodiment is the same as the length in the axial direction AD of the first cylindrical portion 411.

[0052] Next, the rotor 100 will be described with reference to Figures 1 to 4. As shown in Figures 1 to 4, the rotor 100 further includes a first rotor housing 260, a second rotor housing 270, a brake mechanism 280, and bearings 290 and 291. The first rotor housing 260 and the second rotor housing 270 are examples of "cover members."

[0053] The first rotor housing 260 is a disk body with a through-hole at its center that penetrates along the axial direction AD. The first rotor housing 260 is located on the other side of the yoke 110 in the axial direction AD (-X direction). The first rotor housing 260 covers at least a portion of the motor stator 200 and the rotor 100 from the other side in the axial direction AD. The first rotor housing 260 is fixed to the yoke 110.

[0054] Specifically, the outer end portion in the radial direction RD of the first rotor housing 260 is fixed to the other side surface in the axial direction AD of the yoke main body 113 by a plurality of first screws 261. Specifically, the first screws 261 are attached to the first cover screw holes 111 from the other side in the axial direction AD of the yoke main body 113. For example, the number of the plurality of first screws 261 is "8", but is not limited to this.

[0055] Furthermore, the first rotor housing 260 is disposed rotatably relative to the shaft 50. Specifically, the first rotor housing 260 includes a cylindrical portion 262. The cylindrical portion 262 houses the bearing 290. The cylindrical portion 262 is located on the outer side of the bearing 290 in the radial direction RD. The cylindrical portion 262 surrounds the shaft 50 and extends along the axial direction AD.

[0056] The bearing 290 rotatably supports the first rotor housing 260 relative to the shaft 50. The bearing 290 is disposed between the shaft 50 and the cylindrical portion 262. The bearing 290 is, for example, a ball bearing or a rolling bearing.

[0057] The second rotor housing 270 is a disk body with a through-hole at its center that penetrates along the axial direction AD. The second rotor housing 270 is located on one side of the yoke 110 in the axial direction AD (X direction). The second rotor housing 270 covers at least a portion of the motor stator 200 and the rotor 100 from one side in the axial direction AD. The second rotor housing 270 is fixed to the yoke 110.

[0058] Specifically, the outer end portion in the radial direction R of the second rotor housing 270 is fixed to one side surface in the axial direction AD of the yoke main body 113 by a plurality of second screws 271. Specifically, the second screws 271 are attached to the second cover screw holes 112 from one side in the axial direction AD of the yoke main body 113. For example, the number of the plurality of second screws 271 is "8."

[0059] The second rotor housing 270 is located radially inward in the RD direction from the protrusion 114a. As a result, the attachment position of the second rotor housing 270 can be positioned toward the center of the rim portion 400, thereby reducing the axial length of the entire motor 10 in the AD direction. In addition, the presence of the yoke-side contact portion 114 between the second cover screw hole 112 and the rim portion 400 can suppress transmission of vibrations from the tire to the second screw 271.

[0060] Furthermore, the second rotor housing 270 is disposed rotatably relative to the shaft 50. Specifically, the second rotor housing 270 includes a cylindrical portion 272. The cylindrical portion 272 houses a bearing 291. The cylindrical portion 272 is located on the outer side of the bearing 290 in the radial direction RD. The cylindrical portion 272 surrounds the shaft 50 and extends along the axial direction AD.

[0061] The bearing 291 rotatably supports the second rotor housing 270 relative to the shaft 50. The bearing 291 is disposed between the shaft 50 and the cylindrical portion 272. The bearing 291 is, for example, a ball bearing or a rolling bearing.

[0062] The brake mechanism 280 is a substantially cylindrical body. The brake mechanism 280 is located radially outward from the shaft 50 in the radial direction RD. Specifically, the brake mechanism 280 is disposed about a central axis AX extending along the axial direction AD. The brake mechanism 280 is fixed to the second rotor housing 270.

[0063] The inner end of rotor 100 in the radial direction RD directly faces motor stator 200 without being covered by first rotor housing 260 and second rotor housing 270. Motor stator 200 is disposed between first rotor housing 260 and second rotor housing 270.

[0064] The motor 10 is driven by three-phase (U-phase, V-phase, and W-phase) AC power output from three output terminals of a control device. The motor 10 is driven by a U-phase control signal, a V-phase control signal, and a W-phase control signal. When the U-phase control signal, the V-phase control signal, and the W-phase control signal are input to the motor stator 200, the rotor 100 rotates in response to changes in the magnetic field generated in the motor stator 200. This three-phase AC power is connected to the motor stator 200 via power lines (not shown) from an inverter device (not shown) mounted on the electric motorcycle 1020 (see FIG. 5 ). The power lines (not shown) are connected to the motor stator 200 through a through-hole (not shown) provided in the shaft 50.

[0065] The third connection portion 433 includes a through hole 440 that connects the radially inner side to the radially outer side. Specifically, the through hole 440 is provided in the third connection portion 433 that is provided on one side in the axial direction AD of the first cylindrical portion 411. As a result, when a valve 441 is provided in the through hole 440, air can be introduced into the tire from the radially inner side of the third connection portion 433 through the through hole 440 without being obstructed by the yoke 110.

[0066] Next, an electric motorcycle 1020 equipped with the motor 10 according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic diagram of the electric motorcycle 1020 equipped with the motor 10 according to the first embodiment.

[0067] 5, the motor 10 is mounted on an electric two-wheeled vehicle 1020. Examples of electric two-wheeled vehicles include an electric scooter and an electric motorcycle. For example, the motor 10 drives the wheels of the electric two-wheeled vehicle 1020.

[0068] The motor 10 is mounted on an electric motorcycle 1020. In addition to the motor 10, the electric motorcycle 1020 includes a frame 1021, a handlebar 1022, a front wheel 1023, a rear wheel 1024, and a saddle 1025. The rear wheel 1024 is an example of a "wheel." For example, the motor 10 is attached to the rear wheel 1024. Furthermore, the shaft 50 of the motor 10 is attached to the frame 1021. Thus, the rear wheel 1024 is attached to the frame 1021.

[0069] The rear wheels 1024 are rotatably supported at the rear and lower part of the frame 1021. The rear wheels 1024 rotate while in contact with the ground.

[0070] In the first embodiment, the length of the entire motor 10 in the axial direction AD can be reduced.

[0071] Second Embodiment A motor 2010 according to a second embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is an enlarged cross-sectional view showing the configuration of the motor 2010 according to the second embodiment. While the motor 10 according to the first embodiment includes a yoke-side contact portion 114, the motor 2010 according to the second embodiment includes a yoke-side contact portion 2114. Below, differences between the second embodiment and the first embodiment will be described, and descriptions of portions that overlap with the first embodiment will be omitted.

[0072] The yoke 110 includes a yoke main body 113 and a yoke-side contact portion 2114. The yoke main body 113 and the yoke-side contact portion 2114 are a single member. As a result, there is no need to fasten the yoke main body 113 and the yoke-side contact portion 114 together by welding or the like, and the yoke 110 is more resistant to impacts from the rim portion 400 than if separate components were fastened together.

[0073] The yoke side contact portion 2114 is provided on the radially outer side of the yoke main body 113 in the radial direction RD. More specifically, the yoke 110 has the yoke side contact portion 2114 provided on the yoke main body 113 in accordance with the position of the rim portion 400 relative to the yoke 110. For example, the yoke side contact portion 2114 has a cylindrical shape and is provided on the radially outer side of the yoke main body 113 in the radial direction RD. In the axial direction AD, the length of the yoke side contact portion 2114 is a third distance L3.

[0074] The end face of the yoke side contact portion 2114 in the axial direction AD is connected to the outer peripheral surface of the yoke main body 113. Specifically, the other side face of the yoke side contact portion 2114 in the axial direction AD is connected to the outer peripheral surface of the yoke main body 113. In other words, a stepped shape is formed on the outer peripheral surface of the yoke 110. As a result, the weight of the yoke can be reduced compared to when the outer peripheral surface of the yoke 110 is a flat surface.

[0075] In the yoke 110, the length L3 in the axial direction AD of the yoke side contact portion 114 is different from the length L2 in the axial direction AD of the yoke main body 113, or the position of the center in the axial direction AD of the yoke side contact portion 2114 is different from the position of the center in the axial direction AD of the yoke main body 113. Specifically, in the yoke 110 according to the second embodiment, the length L3 in the axial direction AD of the yoke side contact portion 2114 is different from the length L2 in the axial direction AD of the yoke main body 113, and the position of the center in the axial direction AD of the yoke side contact portion 2114 is different from the position of the center in the axial direction AD of the yoke main body 113.

[0076] As described above, according to the second embodiment, for example, the position in the axial direction AD or the length L1 of the first cylindrical portion 411 differs from the position in the axial direction AD or the length L2 of the yoke main body 113, but the yoke 110 is provided with the yoke side contact portion 2114. In other words, the yoke 110 is provided with the yoke side contact portion 2114 corresponding to the position or length L1 of the first cylindrical portion 411 relative to the yoke 110. As a result, the yoke 110 can be made lighter without being larger than a cylindrical yoke.

[0077] Third Embodiment A motor 3010 according to a third embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is an enlarged cross-sectional view showing the configuration of the motor 3010 according to the third embodiment. While the motor 10 according to the first embodiment includes a yoke-side contact portion 114, the motor 3010 according to the third embodiment includes a yoke-side contact portion 3114. Below, differences between the third embodiment and the first embodiment will be described, and descriptions of portions that overlap with the first embodiment will be omitted.

[0078] The yoke 110 includes a yoke main body 113 and a yoke-side contact portion 3114. The yoke main body 113 and the yoke-side contact portion 3114 are a single member. As a result, there is no need to fasten the yoke main body 113 and the yoke-side contact portion 3114 together by welding or the like, and the yoke 110 is more resistant to impacts from the rim portion 400 than if separate components were fastened together.

[0079] The yoke side contact portion 3114 is provided on the radially outer side of the yoke main body 113 in the radial direction RD. More specifically, the yoke 110 has the yoke side contact portion 3114 provided on the yoke main body 113 in accordance with the position of the rim portion 400 relative to the yoke 110. For example, the yoke side contact portion 3114 has a cylindrical shape and is provided on the radially outer side of the yoke main body 113 in the radial direction RD. In the axial direction AD, the length of the yoke side contact portion 3114 is a sixth distance L6.

[0080] Specifically, the length L6 in the axial direction AD of the yoke side contact portion 3114 is equal to or greater than half the length L1 in the axial direction AD of the first cylindrical portion 411. As a result, it is possible to suppress deformation of the first cylindrical portion 411. The length L6 in the axial direction AD of the yoke side contact portion 3114 according to the third embodiment is longer than the length in the axial direction AD of the first cylindrical portion 411.

[0081] The end face of the yoke side contact portion 3114 in the axial direction AD is connected to the outer peripheral surface of the yoke main body 113. Specifically, the other side face of the yoke side contact portion 3114 in the axial direction AD is connected to the outer peripheral surface of the yoke main body 113. In other words, a stepped shape is formed on the outer peripheral surface of the yoke 110. As a result, the weight of the yoke can be reduced compared to when the outer peripheral surface of the yoke 110 is a flat surface.

[0082] In the yoke 110, the length L6 in the axial direction AD of the yoke side contact portion 3114 is different from the length L2 in the axial direction AD of the yoke main body 113, or the position of the center of the axial direction AD of the yoke side contact portion 3114 is different from the position of the center of the axial direction AD of the yoke main body 113. Specifically, in the yoke 110 according to the third embodiment, the length L6 in the axial direction AD of the yoke side contact portion 3114 is different from the length L2 in the axial direction AD of the yoke main body 113, and the position of the center of the axial direction AD of the yoke side contact portion 3114 is different from the position of the center of the axial direction AD of the yoke main body 113.

[0083] As described above, according to the third embodiment, for example, the position in the axial direction AD or the length L1 of the first cylindrical portion 411 differs from the position in the axial direction AD or the length L2 of the yoke main body 113, but the yoke 110 is provided with the yoke side contact portion 3114. In other words, the yoke 110 is provided with the yoke side contact portion 3114 corresponding to the position or length L1 of the first cylindrical portion 411 relative to the yoke 110. As a result, the yoke 110 can be made lighter without being larger than a cylindrical yoke.

[0084] Fourth Embodiment A motor 4010 according to a fourth embodiment of the present invention will be described with reference to Fig. 8. Fig. 8 is an enlarged cross-sectional view showing the configuration of the motor 4010 according to the fourth embodiment. While the motor 10 according to the first embodiment includes a yoke-side contact portion 114, the motor 4010 according to the fourth embodiment includes a yoke-side contact portion 4114. Below, differences between the fourth embodiment and the first embodiment will be described, and descriptions of portions that overlap with the first embodiment will be omitted.

[0085] The yoke 110 includes a yoke main body 113 and a yoke-side contact portion 4114. The yoke main body 113 and the yoke-side contact portion 4114 are a single member. As a result, there is no need to fasten the yoke main body 113 and the yoke-side contact portion 4114 together by welding or the like, and the yoke 110 is more resistant to impacts from the rim portion 400 than if separate components were fastened together.

[0086] The yoke side contact portion 4114 is provided on the radially outer side of the yoke main body 113 in the radial direction RD. More specifically, the yoke 110 has the yoke side contact portion 4114 provided on the yoke main body 113 in accordance with the position of the rim portion 400 relative to the yoke 110. For example, the yoke side contact portion 4114 has a cylindrical shape and is provided on the radially outer side of the yoke main body 113 in the radial direction RD. In the axial direction AD, the length of the yoke side contact portion 4114 is a seventh distance L7.

[0087] An end face in the axial direction AD of the yoke side contact portion 3114 is connected to the outer peripheral surface of the yoke main body 113. Specifically, the other side face in the axial direction AD of the yoke side contact portion 3114 is connected to the outer peripheral surface of the yoke main body 113. Furthermore, one side face in the axial direction AD of the yoke side contact portion 3114 is connected to the outer peripheral surface of the yoke main body 113. In other words, a stepped shape is formed on the outer peripheral surface of the yoke 110 in accordance with the position of the rim portion 400 relative to the yoke 110. As a result, the weight of the yoke can be reduced compared to when the outer peripheral surface of the yoke 110 is a flat surface.

[0088] In the yoke 110, the length L7 of the yoke side contact portion 4114 in the axial direction AD is different from the length L2 of the yoke main body 113 in the axial direction AD, or the position of the center of the yoke side contact portion 4114 in the axial direction AD is different from the position of the center of the yoke main body 113 in the axial direction AD. Specifically, in the yoke 110 according to the fourth embodiment, the length L7 of the yoke side contact portion 4114 in the axial direction AD is different from the length L2 of the yoke main body 113, and the position of the center of the yoke side contact portion 4114 in the axial direction AD is the same as the position of the center of the yoke main body 113 in the axial direction AD.

[0089] As described above, according to the fourth embodiment, for example, the position in the axial direction AD or the length L1 of the first cylindrical portion 411 differs from the position in the axial direction AD or the length L2 of the yoke main body 113, but the yoke 110 is provided with the yoke side contact portion 4114. In other words, the yoke 110 is provided with the yoke side contact portion 4114 corresponding to the position or length L1 of the first cylindrical portion 411 relative to the yoke 110. As a result, the yoke 110 can be made lighter without being larger than a cylindrical yoke.

[0090] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit and scope of the present invention. The drawings mainly show each component in a schematic manner for ease of understanding, and the thickness, length, number, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of creating the drawings. Furthermore, the materials, shapes, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible within a scope that does not substantially depart from the effects of the present invention.

[0091] The present technology can be configured as follows.

[0092] (1) A motor comprising: a fixed portion; a rotating portion that rotates relative to the fixed portion; and a rim portion that supports a tire, wherein the rotating portion comprises: a yoke having a cylindrical yoke main body portion and a yoke side contact portion provided radially outside the yoke main body portion; and a magnet attached to the yoke main body portion, wherein the rim portion has a rim side contact portion that contacts the radially outside of the yoke side contact portion, and wherein the axial length of the yoke side contact portion is different from the axial length of the yoke main body portion, or the position of the axial center of the yoke side contact portion is different from the position of the axial center of the yoke main body portion.

[0093] (2) The motor according to (1), wherein an axial end face of the yoke-side contact portion is connected to an outer peripheral surface of the yoke body portion.

[0094] (3) The motor according to (1) or (2), wherein the axial length of the yoke-side contact portion is equal to or greater than half the axial length of the rim-side contact portion.

[0095] (4) The motor according to any one of (1) to (3), wherein the yoke-side contact portion has a cylindrical shape and is provided radially outward of the yoke main body.

[0096] (5) A motor described in any one of (1) to (4), further comprising a cover member attached to one axial end of the yoke main body, wherein the yoke side contact portion comprises a protrusion protruding from the yoke main body to one axial end and a connection portion connected to the radially outer side of the yoke main body, and the cover member is located radially inward of the protrusion.

[0097] (6) The motor according to (5), wherein one axial end of the yoke body is provided with a screw hole into which a screw is inserted, and the cover member is fixed to the yoke body by the screw.

[0098] (7) The motor according to any one of (1) to (6), wherein the axial length of the connection portion is longer than the axial length of the protrusion.

[0099] (8) The motor according to any one of (1) to (7), wherein the yoke main body and the yoke side contact portion are a single member.

[0100] (9) A motor described in any one of (1) to (8), wherein the rim portion further comprises a rim flange portion protruding radially from both axial ends of the rim side contact portion, the rim flange portion comprises a through hole connecting the radially inner side and the radially outer side, and the through hole is provided in the rim flange portion provided on one axial side of the rim side contact portion.

[0101] (10) An electric vehicle comprising: the motor according to any one of (1) to (9); and a wheel, wherein the motor is attached to the wheel.

[0102] REFERENCE SIGNS LIST 10 Motor 50 Shaft 100 Rotor (rotating portion) 110 Yoke 113 Yoke body 114 Yoke side contact portion 120 Magnet 200 Motor stator 260 First rotor housing 261 First screw 270 Second rotor housing 300 Motor portion (fixed portion) 400 Rim portion 411 Rim side contact portion AD Axial direction RD Radial direction

Claims

1. A motor comprising: a fixed portion; a rotating portion that rotates relative to the fixed portion; and a rim portion that supports a tire, wherein the rotating portion comprises a yoke having a cylindrical yoke main body portion and a yoke side contact portion provided radially outside the yoke main body portion; and a magnet attached to the yoke main body portion, wherein the rim portion has a rim side contact portion that contacts the radially outside of the yoke side contact portion, and wherein the axial length of the yoke side contact portion is different from the axial length of the yoke main body portion, or the position of the axial center of the yoke side contact portion is different from the position of the axial center of the yoke main body portion.

2. The motor according to claim 1, wherein an axial end face of the yoke-side contact portion is connected to the outer peripheral surface of the yoke body portion.

3. The motor according to claim 1, wherein the axial length of said yoke side contact portion is at least half the axial length of said rim side contact portion.

4. The motor according to claim 1, wherein the yoke side contact portion has a cylindrical shape and is provided radially outward of the yoke main body portion.

5. The motor according to claim 1, further comprising a cover member attached to one axial end of the yoke main body, wherein the yoke side contact portion comprises a protruding portion protruding from the yoke main body to one axial side and a connecting portion connected to the radially outer side of the yoke main body, and the cover member is located radially inward of the protruding portion.

6. The motor according to claim 5, wherein one axial end of the yoke body is provided with a screw hole into which a screw is inserted, and the cover member is fixed to the yoke body by the screw.

7. The motor according to claim 5, wherein the axial length of the connection portion is longer than the axial length of the protrusion.

8. The motor according to claim 1, wherein the yoke body and the yoke side contact portion are a single member.

9. The motor described in claim 1, wherein the rim portion further comprises rim flange portions that protrude radially from both axial ends of the rim side contact portion, the rim flange portions having through holes connecting the radially inner side and the radially outer side, the through holes being provided in the rim flange portion provided on one axial side of the rim side contact portion.

10. An electric vehicle comprising: a motor according to any one of claims 1 to 9; and a wheel, wherein the motor is attached to the wheel.

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