CN111146879B

CN111146879B - Motor for electric vehicle

Info

Publication number: CN111146879B
Application number: CN201911059200.3A
Authority: CN
Inventors: 山口雄平; 三分一浩司; 青野真郷
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2018-11-06
Filing date: 2019-11-01
Publication date: 2023-03-10
Anticipated expiration: 2039-11-01
Also published as: CN116154985A; CN111146879A

Abstract

The invention aims to reduce the weight of a motor. A motor (1) for an electric vehicle according to the present invention comprises: a stator (22) including a shaft (21) extending along a central axis (J) extending in the vertical direction; and a rotor (31) that rotates radially outward of the stator (21) about the central axis (J). The rotor (31) includes: an annular yoke (312); and a rim (313) disposed on the outer peripheral side of the yoke (312). The rim (313) comprises a first material and the yoke (312) comprises a second material different from the first material. The rim (313) covers at least a part of the outer peripheral surface of the yoke (312). The invention can reduce the weight of the motor for the electric vehicle.

Description

Motor for electric vehicle

Technical Field

The present invention relates to a motor for an electric vehicle.

Background

In the past, a so-called in-wheel motor (in-wheel motor) in which a motor is disposed in the vicinity of a drive wheel has been known. For example, in japanese patent laid-open No. 2008-155769 (patent document 1), there has been disclosed an in-wheel motor including: an axial motor (axial motor) in which a stator (stator) and a rotor (rotor) are disposed so as to face each other in the direction of the rotation axis thereof; and a braking element that brakes rotation of a bottomed cylindrical wheel that fixes the rotor inside. The wheel of patent document 1 includes: a disk (disk) portion having a hole portion formed in a central portion thereof; and a cylindrical portion extending from a peripheral edge portion of the disk portion toward the vehicle body side. A rim (wheel rim) of a tire (tire) is welded to the outer peripheral surface of the cylindrical portion.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2008-155769

Disclosure of Invention

[ problems to be solved by the invention ]

In patent document 1, a tube portion and a rim (rim) are welded. Therefore, the tube portion and the rim are limited to metal materials that are easily welded. In this case, the range of selection of materials constituting the tube portion and the rim is limited, and therefore it is difficult to reduce the weight of the motor.

In view of the above problems, an object of the present invention is to reduce the weight of a motor for an electric vehicle.

[ means for solving problems ]

One embodiment of a motor for an electric vehicle according to the present invention includes: a stator including a shaft (draft) extending along a central axis extending in an up-down direction; and a rotor rotating on the radial outer side of the stator with the central shaft as the center; the rotor includes: a ring-shaped yoke (yoke); and a rim disposed on an outer peripheral side of the yoke; the rim comprises a first material, the yoke comprises a second material different from the first material, and the rim covers at least a portion of an outer peripheral surface of the yoke.

[ Effect of the invention ]

According to one embodiment of the present invention, the weight of the motor for an electric vehicle can be reduced.

Drawings

Fig. 1 is a schematic diagram of an electric vehicle of an embodiment.

Fig. 2 is a sectional view taken along line II-II of fig. 1.

Fig. 3 is a sectional view of an electric vehicle motor according to an embodiment.

Fig. 4 is a perspective view of a yoke and a rim according to an embodiment.

Fig. 5 is a perspective view of the yoke.

Figure 6 is a partial cross-sectional view of the yoke and rim in area VI of figure 3.

Fig. 7 is a partial schematic view of a yoke and a rim according to a modification of the embodiment.

Fig. 8 is a partial sectional view taken along line VIII-VIII of fig. 7.

Fig. 9 is a sectional view of a stator and a holder of the embodiment.

Fig. 10 is a cross-sectional schematic view of a shaft and stator holder.

Fig. 11 is a cross-sectional schematic view of a modification of the shaft and the stator holder.

Fig. 12 is a cross-sectional schematic view of other variations of the shaft and stator holder.

[ description of symbols ]

1: electric two-wheeled vehicle

2: front wheel

3: rear wheel

3a: tyre for vehicle wheels

4: vehicle body

5: handle (CN)

6：ECU

7: throttle valve

8: battery with a battery cell

9: charging unit

10: motor with a stator having a stator core

11: bearing assembly

20: fixing part

21: shaft

22: stator with a stator core

23: conducting wire

30: rotating part

31: rotor

40: cover cap

41: fastening member

50: liner pad

60: holding device

61: a first cylinder part

62: bent part

63: second cylinder part

64: convex part

65: plate part

66: third barrel part

67: flange

211: large diameter part

212: small diameter part

221: stator core

222: insulator

223: coil

311: magnet

312: magnetic yoke

312a: yoke body

312b: projection part

312b2: end surface in the circumferential direction

312b3: radial outer side surface

312b4, 313b1: upper surface of

312c: axial end face

313: rim ring

313a: groove

313b: holding part

313c: concave part

313d: body of rim ring

313e: rim flange part

313f: convex part

313f1: first convex part

313f2: second convex part

611: shaft through hole

651: plate part through hole

J: center shaft

θ: angle of rotation

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and the description thereof will not be repeated.

In the following description, the extending direction of the central axis J in fig. 2 and 3 is referred to as the vertical direction. One side of the central axis J in the axial direction is simply referred to as "upper side", and the other side is simply referred to as "lower side". The vertical direction is a name for explanation only, and does not limit an actual positional relationship or direction. The direction parallel to the central axis J is simply referred to as the "axial direction", the radial direction about the central axis J is simply referred to as the "radial direction", and the circumferential direction about the central axis J is simply referred to as the "circumferential direction".

In the present specification, the term "extending in the axial direction" includes a state of extending strictly in the axial direction and a state of extending in a direction inclined in a range of less than 45 degrees with respect to the axial direction. Similarly, the term "extending in the radial direction" in the present specification includes a state of strictly extending in the radial direction and a state of extending in a direction inclined in a range of less than 45 degrees with respect to the radial direction.

(vehicle)

An electric vehicle according to an embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a schematic diagram of an electric vehicle according to an embodiment of the present invention. In the present embodiment, an electric motorcycle will be described as an example of an electric vehicle.

As shown in fig. 1, the electric motorcycle 1 includes a front wheel 2, a rear wheel 3, a vehicle body 4, a handle 5, an Electronic Control Unit (ECU) 6, a throttle 7, a battery 8, and a motor 10.

The front wheel 2 and the rear wheel 3 are a pair of wheels. The front wheel 2 and the rear wheel 3 are mounted on the vehicle body 4. At the front of the vehicle body 4, a handle 5 is mounted.

The ECU 6 is disposed inside the vehicle body 4. The ECU 6 is a control device. An accelerator 7 is connected to the ECU 6. The throttle 7 is a speed adjustment mechanism.

The battery 8 is disposed inside the vehicle body 4. The battery 8 is connected to the ECU 6. The battery 8 is charged by a charger 9.

The motor 10 is mounted to the rear wheel 3. The motor 10 is connected to the ECU 6.

(Motor)

A motor according to an embodiment of the present invention will be described with reference to the accompanying drawings. The motor 10 of the present embodiment is an outer rotor (outer rotor) type in-wheel motor. Fig. 2 is a sectional view taken along line II-II of fig. 1. Fig. 3 is a partially enlarged view of fig. 2. As shown in fig. 2 and 3, the motor 10 mainly includes a fixed portion 20, a rotating portion 30, a cover (cover) 40, a gasket (gasket) 50, and a holder 60.

< fixed part >

As shown in fig. 2 and 3, the fixing portion 20 includes a shaft 21, a stator 22, and a lead wire 23.

The shaft 21 extends along a central axis J extending in the vertical direction. The shaft 21 of the present embodiment is a fixed shaft. The shaft 21 is made of metal, for example.

As shown in fig. 3, the shaft 21 includes a large diameter portion 211 and a small diameter portion 212. The small diameter portion 212 has a smaller diameter than the large diameter portion 211. The outer peripheral surface of the small diameter portion 212 is connected to, for example, a bearing 11, a seal member, and the like. The small diameter portion 212 of the present embodiment is located at the upper end and the lower end of the shaft 21, and the large diameter portion is located at the center. The diameter of the shaft may be increased in stages from the end portions to the central portion.

As shown in fig. 2 and 3, the stator 22 has an annular shape. The center of the stator 22 coincides with the central axis J of the motor 10. The stator 22 includes a stator core 221, an insulator (insulator) 222, and a coil 223.

The stator core 221 is formed by laminating magnetic steel plates in the axial direction, for example. The stator core 221 includes a plurality of core wraps and teeth (teeth) arranged in a circumferential direction. The core pack is annular concentric with the central axis J. The teeth protrude from the core pack toward the radially outer side. The teeth are provided in plural numbers, extend in the radial direction from the core pack, and are arranged with slits (slots) in the circumferential direction.

The insulator 222 covers at least a portion of the stator core 221. The insulator 222 is an insulating member that electrically insulates the stator core 221 and the coil 223. An insulator 222 is mounted to each tooth.

The coil 223 excites the stator core 221. The coil 223 is configured by winding a coil wire around each tooth via an insulator 222. The coil 223 is arranged in plurality in the circumferential direction.

The lead wires 23 are connected to the stator 22 at the upper side of the stator 22. The lead wire 23 is drawn out to the upper side of the stator 22 through a plate portion through hole 651 of the plate portion 65 of the holder 60, which will be described later. In fig. 3, the lead wire 23 connected to the coil wire is drawn out to the upper side through the plate portion through hole 651 of the plate portion 65, but the present invention is not limited thereto. The lead wires connected to the circuit board or the coil wires may be drawn from the upper side to the lower side, or may be drawn from the lower side to the upper side.

< rotating part >

The rotating portion 30 rotates toward the fixed portion 20. The rotating portion 30 includes a rotor 31. The rotor 31 rotates radially outward of the stator 22 around the central axis J.

As shown in fig. 2 and 3, the rotor 31 includes a magnet (magnet) 311, a yoke 312, and a rim 313.

The magnet 311 is disposed radially outside the stator 22. The magnet 311 is configured such that north (N) poles and south (S) poles are arranged in the circumferential direction. The magnet 311 may include, for example, a plurality of permanent magnets arranged in the circumferential direction, or may include one annular permanent magnet.

Fig. 4 is a perspective view of a yoke and a rim ring according to an embodiment. In fig. 4, components other than the yoke and the rim are not shown. Fig. 5 is a perspective view showing only the yoke. As shown in fig. 2 to 4, the yoke 312 is disposed radially outward of the magnet 311. The yoke 312 has a ring shape. Specifically, as shown in fig. 4 and 5, the yoke 312 includes a yoke body 312a and a protruding portion 312b. The yoke body portion 312a and the protruding portion 312b are formed of one member. The yoke body portion 312a has a ring shape. The protruding portion 312b is a bent portion that bends one end side in the axial direction of one member.

The protruding portion 312b extends radially outward from the yoke body portion 312 a. The plurality of projections 312b are provided in the circumferential direction. Specifically, the plurality of projections 312b are provided at intervals in the circumferential direction. The protruding portion 312b extends radially outward from the axial end of the yoke body portion 312 a. This makes it possible to easily provide the projection 312b.

The protruding portion 312b may be provided only on one axial end side of the yoke body portion 312a, or may be provided on one end side and the other end side. In fig. 5, the plurality of projections 312b extend radially outward from the upper end and the lower end of the yoke body 312 a. The circumferential position of the protruding portion 312b on the upper end side and the circumferential position of the protruding portion 312b on the lower end side are different from each other.

The protrusion 312b is provided with a through hole 312b1 through which a fastening member 41 is inserted, and the fastening member 41 fastens the cover 40. The through hole 312b1 penetrates in the axial direction. The plurality of through holes 312b1 are concentrically arranged around the central axis J.

As shown in fig. 2, rim 313 mounts tire 3a. As shown in fig. 3 and 4, the rim 313 is disposed on the outer peripheral side of the yoke 312. The rim 313 and the yoke 312 are an integral part.

The bead 313 comprises a first material. The yoke 312 comprises a second material different from the first material. As described above, the rim 313 and the yoke 312 comprise any of a variety of materials. Therefore, the rim 313 and the yoke 312 can be made of materials selected to reduce the weight while maintaining their functions. Therefore, the motor 10 can be provided with a reduced weight.

The specific gravity of the first material is less than the specific gravity of the second material. This can reduce the weight of the rim 313. The first material contains, for example, aluminum, and the second material contains, for example, iron. Specifically, the first material is an aluminum alloy and the second material is an iron alloy.

The yoke 312 is a pressed product. The rim 313 is a cast item. Specifically, after the yoke 312 is formed, the yoke 312 and the rim 313 are formed integrally by casting. This makes it possible to easily manufacture an integrated product of the rim 313 and the yoke 312. Therefore, the weight of the motor 10 can be easily reduced.

The rim 313 covers at least a part of the outer peripheral surface of the yoke 312. In fig. 4, the rim 313 covers the entire outer peripheral surface of the yoke body portion 312 a. In detail, the rim 313 comprises: a rim body portion 313d radially overlapping the outer peripheral surface of the yoke 312; and a rim flange (rim flange) portion 313e extending radially outward from the upper and lower end portions of the rim body portion 313 d.

The bead 313 includes grooves 313a between adjacent protrusions 312b in the circumferential direction. In this case, the volume of the rim 313 can be reduced, and therefore the weight of the motor 10 can be further reduced. The groove 313a extends in the circumferential direction.

As shown in fig. 4, the circumferential end surface 312b2 of the projection 312b is covered with the bead 313. The circumferential end surface 312b2 abuts against the rim 313. This can improve the strength of the circumferential end of the protruding portion 312b against a load. That is, the yoke 312 and the rim 313 can be prevented from being displaced in the circumferential direction.

Further, the radially outer side surface 312b3 of the projection 312b is covered by the rim 313. The radially outer surface 312b3 abuts the rim 313. This prevents the yoke 312 and the rim 313 from being displaced in the radial direction.

Figure 6 is a partial cross-sectional view of the yoke and rim in area VI of figure 3. In fig. 6, components other than the yoke and the rim are not shown. As shown in fig. 3 and 6, the axial end face 312c of the yoke 312 is covered with the rim 313. As shown in fig. 6, the rim 313 includes a holding portion 313b covering at least a part of the axial end surface 312c of the yoke 312. More specifically, the holding portion 313b is a portion of the rim 313 that covers at least the axial end of the yoke main body 312 a. The rim 313 covers a part of the axial end surface 312c of the yoke 312. The rim 313 may cover the entire axial end surface 312c of the yoke 312.

In fig. 6, the upper surface 312b4 of the protruding portion 312b is not covered by the holding portion 313 b. The upper surface 313b1 of the holding portion 313b is flush with the upper surface 312b4 of the projection 312b. The lower surface of the holding portion 313b is located on the same plane as the lower surface of the protruding portion 312b. In this case, the volume of the rim 313 can be reduced, and thus the weight of the motor 10 can be further reduced. An upper surface 313b1 and a lower surface (not shown) of the holding portion 313b are axial end surfaces of the holding portion 313 b. The upper surface 312b4 and the lower surface of the projection 312b are axial end surfaces of the projection 312b. The lower surface of the holding portion 313b, not shown, is an axial end surface of the holding portion 313b covering the other axial end of the yoke body 312 a.

Fig. 7 and 8 are views showing modifications of the embodiment of the present invention. Fig. 7 is a partial schematic view of a yoke and a rim of a modified example of the embodiment as viewed from the upper side in the axial direction. Fig. 7 is a schematic representation of a different aspect from fig. 4. Fig. 8 is a partial sectional view taken along line VIII-VIII of fig. 7. As shown in fig. 7 and 8, the holding portion 313b may cover a part of the upper surface 312b4 of the protruding portion 312b. The holding portion 313b may cover a part of the lower surface of the protrusion 312b. In this case, the rim 313 and the yoke 312 can be firmly fastened.

The holding portion 313b may cover the entire upper surface 312b4 of the projection 312b. The holding portion 313b may cover the entire lower surface of the protruding portion 312b. In this case, a through hole through which the fastening member 41 is inserted is also formed in the holding portion 313b, and the fastening member 41 fastens the cover 40.

As shown in fig. 4, the rim 313 includes a projection 313f that projects radially outward from the outer peripheral surface of the rim body portion 313 d. The rim 313 includes a plurality of protrusions 313f. The protrusion 313f includes a first protrusion 313f1 and a second protrusion 313f2. Specifically, the projection 313f is connected to an axial end surface of at least one bead flange portion 313 e. In fig. 4, there are provided: a first projection 313f1 connected to an axial end surface of one of the bead flange portions 313 e; and a second projection 313f2 connected to an axial end surface of the other bead flange portion 313 e. The first projection 313f1 and the second projection 313f2 are different in circumferential position. In this case, since the first convex portion 313f1 and the second convex portion 313f2 can be arranged to be shifted in the circumferential direction, the length of the concave portion 313c necessary for fastening can be secured. The first convex portion 313f1 and the second convex portion 313f2 are also different in position in the axial direction. The bead body portion 313d, the bead flange portion 313e, and the projection 313f are formed from one piece.

As shown in fig. 6 and 8, the convex portion 313f includes a concave portion 313c through which the fastening member 41 is inserted. By using only the portion to which the fastening member 41 is fastened as the projection 313f, the volume of the rim 313 can be reduced. In the present embodiment, the convex portion 313f overlaps the protruding portion 312b in the axial direction. Specifically, the recess 313c is continuous with the through hole 312b1 of the projection 312b and is recessed in the axial direction. The inner circumferential surface of the recess 313c includes a female screw portion. The male screw portion of the fastening member 41 is fastened to the female screw portion. The rim 313 and the fastening member 41 are fixed by the female screw portion of the concave portion 313c and the male screw portion of the fastening member 41.

The thickness of the rim 313 in the axial direction is larger than the thickness of the yoke 312 in the axial direction. The length of the rim 313 in the radial direction is greater than the length of the yoke 312 in the radial direction.

< shroud >)

As shown in fig. 2 and 3, the cover 40 is disposed at least on one of the upper and lower sides in the axial direction of the rotor 31 and the stator 22. The covers 40 of the present embodiment are disposed on the upper and lower sides in the axial direction of the rotor 31 and the stator 22. The cover 40 is, for example, a wheel cover. The cover 40 is mounted to the shaft 21.

The cover 40 has a disk shape. The cover 40 is mounted to the shaft 21. The cover is provided with a through hole through which the shaft 21 passes.

The cover 40 is secured to at least one of the rim 313 and the yoke 312. In this case, the welding can be omitted and the cover 40 can be attached. In fig. 2 and 3, the cover 40 is fastened to the protrusion 312b of the yoke 312 by the fastening member 41. Specifically, as shown in fig. 3, the cover 40 is provided with a through hole 411 through which the fastening member 41 is inserted. The fastening member 41 passes through the through hole 411 of the cover 40, the through hole 312b1 (see fig. 6) of the projection 312b, and the recess 313c (see fig. 6) of the rim 313, and fastens the yoke 312 and the cover 40 integrally with the rim 313. By providing the through hole 312b1 in the protruding portion 312b, the thickness of the yoke body portion 312a in the radial direction can be reduced. This can further reduce the weight of the motor 10. The rim 313 and the yoke 312 are fastened to the cover 40 by the fastening members 41.

The circumferential position for fastening the cover 40 on the upper side and the circumferential position for fastening the cover 40 on the lower side are different from each other. Specifically, as shown in fig. 4, the positions in the circumferential direction extending radially outward from the upper end and the lower end of the projection 312b are different from each other. The through hole 411 of the cover 40 is provided in a position aligned with the circumferential direction of the through hole 312b1 of the projection 312b.

< gasket >

As shown in fig. 2, the pad 50 is disposed between the rim 313 and the cover 40. The gasket 50 is formed, for example, by applying a liquid gasket to the interface between the rim 313 and the cover 40 and drying the liquid gasket. The pad may be further disposed in a portion where the lead 23 is inserted, or the like.

< holder >

As shown in fig. 2 and 3, the holder 60 is mounted to the shaft 21. In detail, the holder 60 is fixed to the large diameter portion 211 of the shaft 21. By inserting the holder 60 from the small diameter portion 212 side, the holder can be press-fitted into the large diameter portion 211 without damaging the outer peripheral surface of the small diameter portion 212 of the shaft 21.

The holder 60 holds the fixed part 20 or the rotating part 30. The holder 60 of the present embodiment holds the stator 22.

Fig. 9 is a cross-sectional view of an embodiment stator and holder. In fig. 9, parts other than the stator and the stator holder are not shown. As shown in fig. 9, the retainer 60 includes a first tube portion 61, a bent portion 62, a second tube portion 63, a convex portion 64, a plate portion 65, a third tube portion 66, and a retainer flange portion 67. The first tube portion 61, the bent portion 62, the second tube portion 63, the protruding portion 64, the plate portion 65, the third tube portion 66, and the retainer flange portion 67 are arranged in this order from the radially inner side toward the radially outer side. The holder 60 is constructed of one member. Specifically, the holder 60 is a pressed article.

Specifically, the holder 60 is made of metal. The holder 60 is formed by bending a plate-shaped metal member. The holder 60 and the shaft 21 comprise the same material. For example, the holder 60 and the shaft 21 include iron. With the same material, welding of the holder 60 and the shaft 21 is easy.

The first cylinder portion 61 includes a shaft through hole 611. The shaft is press-fitted into the inner peripheral surface of the shaft through hole 611. The first cylindrical portion 61 may be welded to the shaft 21. The second tube 63 may be welded to the shaft 21.

The second cylindrical portion 63 contacts at least a part of the first cylindrical portion 61 and overlaps with the first cylindrical portion 61 in the radial direction. The first cylindrical portion 61 extends in the same direction as the second cylindrical portion 63. In the present embodiment, the first cylindrical portion 61, the second cylindrical portion 63, and the shaft 21 extend in the axial direction.

In the retainer 60, the first cylindrical portion 61 and the second cylindrical portion 63 pressed into the shaft 21 overlap in the radial direction, and at least a part of them contact each other. Therefore, the fastening strength of the motor 10 can be improved.

Fig. 10 is a cross-sectional schematic view of a shaft and stator holder. Fig. 11 is a cross-sectional schematic view of a modification of the shaft and the stator holder. Fig. 12 is a cross-sectional schematic view of other variations of the shaft and stator holder. In fig. 10 to 12, the parts other than the shaft and the stator holder are not shown. As shown in fig. 10 to 12, the relationship Lb/2 La ≦ 2Lb between the axial length La of the first cylindrical portion 61 and Lb of the second cylindrical portion 63. More preferably, la ≦ 2Lb as shown in FIGS. 10 and 11.

The first tube portion 61 and the second tube portion 63 include a welded portion that is joined to each other. The welded portion is provided at a portion where the first cylindrical portion 61 and the second cylindrical portion 63 overlap in the radial direction. That is, a portion where the plate-shaped metal members are folded back and overlapped is welded. The welded portion may be provided on the entire portion of the first tube portion 61 and the second tube portion 63 overlapping in the radial direction, or may be provided on a part thereof. In the latter case, the welded portion is provided at an end portion opposite to the bent portion 62 in the axial direction. That is, the lower end of the first cylindrical portion 61 and the lower end of the second cylindrical portion 63 are welded. In addition, when the shaft 21 and the first cylindrical portion 61 are welded, the shaft 21 and the first cylindrical portion 61 include a welded portion that is joined to each other. In addition, when the shaft 21 and the second cylindrical portion 63 are welded, the shaft 21 and the second cylindrical portion 63 include a welded portion that is in contact with each other.

The ends of the first tube portion 61 and the second tube portion 63 opposite to the bent portion 62 may not be joined, but are preferably joined. The bonding is not limited to welding, and an adhesive or the like may be used.

As shown in fig. 9, the bent portion 62 connects the upper end portion of the first tube portion 61 and the upper end portion of the second tube portion 63. The inflection portion 62 has an R shape. The R-shape is a shape curved in an arc shape.

In the present embodiment, the holder 60 includes one metal member. The first tube portion 61 and the second tube portion 63 are folded back the metal member by the bent portion 62. Since the first tube portion 61 and the second tube portion 63 overlap each other by being folded back, the strength of the portion of the holder 60 that requires strength is increased. The portions of the retainer 60 that do not require strength are not overlapped by the metal members due to the reduced weight.

The projection 64 is connected to the lower end of the second cylindrical portion 63. The convex portion 64 is provided in the entire circumferential direction. The convex portion 64 is between the plate portion 65 and the second cylindrical portion 63 and protrudes downward. The provision of the convex portion 64 can extend the axial length of the second tube portion 63. Therefore, the second tube portion 63 overlapping the first tube portion 61 can be extended, and the fastening strength can be further improved.

The plate portion 65 extends in the radial direction from the lower end of the second cylindrical portion 63. Specifically, the plate portion 65 extends in the radial direction from the lower end portion of the second tube portion 63 via the convex portion 64. The plate portion 65 includes a plate portion through hole 651 through which a lead wire is inserted.

The plate portion 65 extends so as to be inclined toward the lower side in the axial direction toward the radially outer side. Specifically, the angle θ formed by the plate portion 65 and the central axis J is preferably 70 degrees or more and 90 degrees or less. If the angle θ formed by the plate portion 65 and the central axis J is within the above range, the axial length Lb of the second tube portion 63 can be extended. Therefore, the second tube section 63 overlapping the first tube section 61 can be extended, and the fastening strength can be further improved. The angle θ formed by the plate portion 65 and the central axis J is set as appropriate so as not to interfere with a lead wire or the like. From the viewpoint of the above and improvement of fastening strength, the angle θ is more preferably 80 degrees or more and less than 90 degrees.

The third cylindrical portion 66 extends upward from the outer edge of the plate portion 65. The connecting region of the third cylindrical portion 66 and the plate portion 65 is R-shaped. The third cylindrical portion 66 radially overlaps the first cylindrical portion 61 and the second cylindrical portion 63. That is, the third tubular portion 66 extends in the same direction as the first tubular portion 61 and the second tubular portion 63. Thereby, the holder 60 can be reduced in the axial direction, so that the motor 10 can be miniaturized.

The retainer flange portion 67 extends radially from the third cylinder portion 66. Specifically, the retainer flange portion 67 extends radially outward from the upper end of the third tube portion 66. The boundary region between the retainer flange 67 and the third cylinder 66 is R-shaped.

The upper surface of the stator 22 meets the lower surface of the retainer flange 67. The upper surface of the stator 22 is in contact with the lower surface of the retainer flange 67, whereby the accuracy of the axial position of the stator 22 can be improved.

The retainer flange portion 67 may be provided over the entire circumferential direction or may be provided over a part of the circumferential direction. In addition, the length in the radial direction of the retainer flange portion 67 may also be smaller than the radial length of the stator 22. In detail, the lower surface of the retainer flange portion 67 may be in contact with the entire upper surface of the stator 22, or may be in contact with a part of the upper surface of the stator 22. In fig. 9, the retainer flange portion 67 is in contact with the stator core of the stator 22, but may be in contact with another member such as a coil.

(modification example)

The motor for an electric vehicle according to the above embodiment will be described by taking an in-wheel motor of an electric motorcycle as an example. The motor for an electric vehicle according to the present invention is not limited to an electric two-wheeled vehicle, and may be a motor for an electric four-wheeled vehicle, for example. The electric vehicle motor according to the present invention is not limited to an in-wheel motor as long as it is a motor for an electric vehicle.

In the embodiment, the yoke 312 includes a protrusion 312b, the protrusion 312b is formed with a through hole 312b1 into which the fastening member 41 is inserted, and the fastening member 41 fastens the cover 40. In the yoke of the present invention, the projection 312b may be omitted. In this case, the rim 313 and the cover 40 are fastened by the fastening member 41.

In the above embodiment, the fastening portions of the holder 60 to the shaft 21 are the first cylindrical portion 61 and the second cylindrical portion 63, and have a double structure of being bent twice via the bent portion 62. The fastening portion with the shaft 21 in the holder 60 may also have a triple structure. In addition, from the viewpoint of weight reduction, a double structure is preferable.

The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the embodiments, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. A motor for an electric vehicle, comprising:

a stator including a shaft extending along a central axis extending in an up-down direction; and

a rotor that rotates on the outside in the radial direction of the stator around the central axis; and is provided with

The rotor includes:

an annular yoke; and

a rim disposed on an outer peripheral side of the yoke;

the bead ring comprises a first material and a second material,

the yoke comprises a second material different from the first material,

the rim and the yoke are formed integrally by casting,

the rim covers at least a part of the outer peripheral surface of the yoke and the axial end surface of the yoke, and the magnet is positioned on the inner peripheral surface of the yoke exposed from the rim.

2. The motor for an electric vehicle according to claim 1, wherein a specific gravity of the first material is smaller than a specific gravity of the second material.

3. The motor for an electric vehicle according to claim 1, wherein

The first material is an aluminum alloy and,

the second material is a ferrous alloy.

4. The motor for an electric vehicle according to any one of claims 1 to 3, further comprising:

a cover disposed at least one of upper and lower sides of the rotor and the stator in an axial direction, and attached to the shaft; and is

The cover is secured to at least one of the rim and the yoke.

5. The motor for an electric vehicle according to claim 4, wherein

The yoke includes:

an annular yoke body portion; and

a protrusion extending radially outward from the yoke body;

the protruding portion is provided in plurality in the circumferential direction,

the cover is fastened to the protrusion by a fastening member.

6. The motor for an electric vehicle according to claim 5, wherein

The rim comprises:

a rim body portion radially overlapping an outer peripheral surface of the yoke body portion;

a bead flange portion extending radially outward from an upper end portion and a lower end portion of the bead body portion; and

a projection portion that projects radially outward from the outer peripheral surface of the bead body portion and is continuous with an axial end surface of at least one bead flange portion;

the convex portion includes a concave portion through which the fastening member passes.

7. The motor for an electric vehicle according to claim 6, wherein

The bead comprises a plurality of the projections,

the plurality of projections include:

a first projection attached to one of the rim flanges; and

the second convex part is connected with the other rim flange;

the first projection and the second projection are different in circumferential position.

8. A motor for an electric vehicle according to claim 5, wherein a groove is provided in the rim between adjacent protrusions in a circumferential direction.

9. The motor for an electric vehicle according to claim 8, wherein a circumferential end surface of the protrusion is covered with the bead.

10. The motor for an electric vehicle according to claim 5, wherein

The rim includes a holding portion covering an axial end surface of the yoke,

the upper surface of the holding portion and the upper surface of the protruding portion are located on the same plane.

11. The motor for an electric vehicle according to claim 5, wherein

The rim includes a holding portion covering an axial end surface of the yoke,

the holding portion covers a part of an upper surface of the protruding portion.

12. The motor for an electric vehicle according to claim 4, further comprising:

a gasket disposed between the rim and the cover.