JP2016222164A - In-wheel motor drive unit and electric vehicle having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor drive unit which can reduce vibration and noise in a cabin.SOLUTION: An in-wheel motor drive unit (10) comprises: a wheel hub bearing part (11) which rotatably rotates a wheel hub (12); a connecting part (16) which is arranged at the wheel hub bearing part, and connected to a vehicle body side member (101); a motor part (31) for driving a wheel hub; and a connecting implement (41) which includes an elastic member (45) interposed between the motor part and the wheel hub bearing part, makes an axial line (P) of a motor rotating shaft of the motor part offset from an axial line (O) of the wheel hub, and attaches it to the wheel hub bearing.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an in-wheel motor drive device that is arranged in a space area in a road wheel of a wheel and drives the wheel, and more particularly to a structure that supports a motor unit.

  In-wheel motors are not only less burdensome on the environment because they are electrically driven, but they are installed in the wheels of automobiles and drive the wheels, so they have a larger cabin space than engine cars. It can be secured and is advantageous. As such an in-wheel motor, the thing as described in Unexamined-Japanese-Patent No. 2010-1116017 (patent document 1) is conventionally known, for example. The in-wheel motor described in Patent Literature 1 includes a casing that forms an outer shell of the in-wheel motor, and seats that are formed on the front side and the rear side of the casing in the vehicle longitudinal direction. These seats are provided with female screw holes. The male screw that penetrates the trailing arm is screwed into the female screw hole of the seat so that the seat of the casing is fixedly attached to the trailing arm.

JP 2010-1116017 A

  The present inventor has found that there is a further improvement in the conventional in-wheel motor. In other words, the conventional in-wheel motor is bolted to a suspension member such as a trailing arm and rigidly connected to the vehicle body side as shown in Patent Document 1, so that the vibration of the motor unit is transmitted to the vehicle body during in-wheel motor operation. It was easy to cause vibration and noise in the passenger compartment.

  In view of the above circumstances, an object of the present invention is to provide an in-wheel motor drive device that can reduce vibration and noise in a vehicle compartment.

  For this purpose, an in-wheel motor drive device according to the present invention drives a wheel hub bearing portion that rotatably supports a wheel hub, a connecting portion that is provided on the wheel hub bearing portion and is connected to a vehicle body side member, and a wheel hub. A motor part that includes the elastic member interposed between the motor part and the wheel hub bearing part, and a coupling tool that is attached to the wheel hub bearing part by offsetting the axis of the motor rotation shaft of the motor part from the axis of the wheel hub.

  According to the present invention, the motor part is supported by the wheel hub bearing part via the elastic member. The vibration and noise of the motor unit are blocked by the elastic member and are difficult to transmit to the wheel hub bearing unit. Since the connecting portion of the wheel hub bearing portion is connected to the vehicle body side member, it is difficult for vibration and noise of the motor portion to be transmitted to the vehicle body, and riding comfort performance is improved as compared with the conventional case. The vehicle body side member refers to a member attached to the vehicle body as viewed from the member to be described, and includes not only the vehicle body but also a part interposed between the vehicle body and the member to be described, for example, a suspension member.

  The motor unit may directly drive the wheel hub. However, as an embodiment of the present invention, the motor unit further includes a reduction unit that is attached to the motor unit and decelerates the output of the motor unit and transmits it to the wheel hub. According to this embodiment, since the speed reduction part is attached to the motor part, the vibration and noise of the speed reduction part are blocked by the elastic member described above, and are difficult to be transmitted to the wheel hub bearing part and the vehicle body side member.

  The arrangement of the elastic member is not particularly limited, but as a preferred embodiment of the present invention, a plurality of elastic members are arranged at intervals in the circumferential direction around the motor rotation shaft of the motor unit. According to this embodiment, a motor part can be suitably attached to a wheel hub bearing part. In the case where a plurality of couplers are arranged at intervals in the circumferential direction, a sealing material made of a polymer material is disposed between adjacent couplers, and the connection portion between the wheel hub bearing portion and the motor portion may be sealed. .

  The shape of the plurality of elastic members is not particularly limited, but as a further preferred embodiment of the present invention, the plurality of elastic members are formed to be thick in the radial direction and thin in the circumferential direction around the axis of the wheel hub. According to this embodiment, the elastic coefficient when the elastic member elastically deforms in the circumferential direction around the axis of the wheel hub can be reduced, and the elastic coefficient when elastically deformed in the radial direction can be increased. Therefore, vibration and noise in the rotational direction of the wheel hub can be effectively blocked. As another embodiment of the present invention, the elastic member may have the same thickness dimension regardless of a specific direction.

  Although the structure of the coupling tool is not particularly limited, as one embodiment of the present invention, the coupling tool is attached to one of the motor part and the wheel hub bearing part, and the other is attached to the other and penetrates the outer cylinder member. And a shaft member. The elastic member has a cylindrical shape and is disposed in an annular gap between the outer cylinder member and the shaft member.

  The in-wheel motor drive apparatus of this invention is provided in each wheel of an electric vehicle. Therefore, as one embodiment, the electric vehicle of the present invention includes a plurality of the in-wheel motor drive devices described above, and the in-wheel motor drive devices are provided on a plurality of wheels arranged separately in the vehicle width direction or the vehicle front-rear direction. Therefore, the elastic coefficient of the elastic member of the in-wheel motor driving device is different for each in-wheel motor driving device. According to such an embodiment, the running performance of the electric vehicle can be given characteristics by making the elastic coefficient of the elastic member different between the left and right wheels in the vehicle width direction and / or the front and rear wheels of the electric vehicle.

  Alternatively, as another embodiment, the electric vehicle includes a plurality of the above-described in-wheel motor driving devices, and the in-wheel motor driving devices are respectively provided on a plurality of wheels arranged separately in the vehicle width direction or the vehicle front-rear direction. The distance from the axis of the wheel hub bearing portion of the in-wheel motor drive device to the elastic member is different for each in-wheel motor drive device. According to such an embodiment, the running performance of the electric vehicle can be given characteristics by making the elastic coefficient of the elastic member different between the left and right wheels in the vehicle width direction and / or the front and rear wheels of the electric vehicle.

  As described above, according to the present invention, it is difficult for noise and vibration of the motor unit to be transmitted to the vehicle body, and vibration and noise in the passenger compartment can be reduced.

1 is an overall view showing an in-wheel motor drive device according to an embodiment of the present invention. It is a longitudinal cross-sectional view which shows the in-wheel motor drive device of the embodiment. It is an expanded sectional view which takes out and shows an elastic member from the embodiment. It is a top view which shows typically the electric vehicle which comprises multiple in-wheel motor drive devices of the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall view showing an in-wheel motor drive device according to an embodiment of the present invention, showing a state viewed from the inner side in the vehicle width direction. In FIG. . FIG. 2 is a longitudinal sectional view showing the in-wheel motor drive device of the embodiment, and shows a section cut along a virtual plane including the axis of the wheel hub and the axis of the motor rotation shaft. FIG. 3 is an enlarged cross-sectional view showing the elastic member taken out from the embodiment, and corresponds to the circled portion in FIG. 1. The in-wheel motor drive device 10 of the present embodiment includes a wheel hub bearing portion 11 that rotatably supports a wheel hub 12, a motor portion 31 that drives the wheel hub 12, and a wheel hub that decelerates the output of the motor portion 31. And a speed reduction part 21 for transmitting to the motor. The in-wheel motor drive device 10 is attached to the vehicle body via the suspension member 101 so that the axis O of the wheel hub 12 extends in the vehicle width direction. The wheel hub bearing portion 11 is disposed on the outer side in the vehicle width direction, the motor portion 31 is disposed on the inner side in the vehicle width direction, and the speed reduction portion 21 is disposed therebetween.

  As shown in FIG. 2, the wheel hub bearing portion 11 includes a wheel hub 12 corresponding to the inner ring of the bearing, a rolling element 13 in the first row, a rolling element 14 in the second row, and a non-rotating outer ring member corresponding to the outer ring of the bearing. 15 and constitutes a double row rolling bearing. A connecting portion 16 that protrudes upward is formed on the upper portion of the outer ring member 15. The connecting portion 16 is for connecting to the vehicle body side member, and the connecting portion 16 is formed with a plurality of female screw holes 16m. A suspension member 101 extending from the vehicle body is abutted against the connecting portion 16, and a bolt 102 penetrating the suspension member 101 is screwed into the female screw hole 16m. Thereby, the in-wheel motor drive device 10 is attached and fixed to the vehicle body side member.

  The suspension member 101 is, for example, an arm member that extends in the vehicle width direction and swings in the vertical direction with the vehicle width direction inner end as a base end and the vehicle width direction outer end as a free end. Alternatively, suspension member 101 may be an arm member that extends in the vehicle front-rear direction of the electric vehicle and swings in the vertical direction with the front end serving as a base end and the rear end serving as a free end. Alternatively, the suspension member 101 may be a shock absorber, and is not particularly limited as long as it is a member of a suspension device.

  The wheel hub 12 has a shaft portion 12b and a tube portion 12c. The shaft portion 12 b extends along the axis O of the wheel hub 12 and is rotatably supported by the speed reduction portion casing 27 via the rolling bearing 17. The cylindrical portion 12c is provided coaxially with the axis O, and the inner raceway surface of the rolling element 13 is formed on the outer peripheral surface of the cylindrical portion 12c. An inner ring member 18 is attached and fixed to the outer peripheral surface of the cylindrical portion 12c. The inner ring member 18 constitutes the inner raceway surface of the rolling element 14. An internal gear 12d is formed on the inner peripheral surface of the cylindrical portion 12c.

  The motor unit 31 includes a motor rotation shaft 32 and a motor unit casing 33. The motor section casing 33 is a cylindrical body arranged coaxially with the axis P of the motor rotation shaft 32. The axis P of the motor rotating shaft 32 extends in parallel with the axis O of the wheel hub 12. The motor unit 31 is arranged offset downward from the wheel hub bearing unit 11. The motor rotating shaft 32 extends from the motor portion 31 so as to protrude outward in the vehicle width direction, and an external gear 34 is formed at the tip of the motor rotating shaft 32.

  The speed reduction part 21 is a parallel shaft type speed reducer, and includes a shaft part 22 extending in parallel with the axis O, external gears 23 and 24 formed at both ends of the shaft part 22, rolling bearings 25 such as ball bearings, 26 and a speed reduction part casing 27. The axis line Q of the shaft portion 22 and the external gears 23 and 24 are disposed offset above the axis line O of the wheel hub 12. The external gear 23 is relatively disposed on the inner side in the vehicle width direction, and the external gear 24 is relatively disposed on the outer side in the vehicle width direction. The external gear 23 has a larger diameter than the external gear 24.

  The external gear 23 has a larger diameter than the external gear 34 and meshes with the external gear 34. The external gear 24 has a smaller diameter than the external gear 23 and meshes with the internal gear 12d. The deceleration unit 21 decelerates the output of the motor rotation shaft 32 and transmits it to the wheel hub 12.

  The speed reduction part casing 27 is a cylindrical body surrounding the external gear 23, and the lower part of the speed reduction part casing 27 protrudes downward from the motor part casing 33. And the vehicle width direction inner side end of the deceleration part casing 27 is abutted by the vehicle width direction outer side end of the motor part casing 33, and both are couple | bonded so that relative movement is impossible. For this reason, the deceleration part casing 27 and the motor part casing 33 can be regarded as one common member.

  The vehicle width direction inner side end of the speed reduction part casing 27 supports the first end of the shaft part 22 via the rolling bearing 25 so as to be rotatable. The outer end in the vehicle width direction of the speed reduction unit casing 27 supports the second end portion of the shaft portion 22 via the rolling bearing 26 so as to be rotatable. For this reason, the shaft portion 22 is supported at both ends by the speed reduction portion casing 27. A cylindrical portion 27 c extending in parallel with the axis Q is formed on the surface of the speed reduction portion casing 27.

  The cylindrical portion 27c is disposed at a front portion and a rear portion of the speed reduction portion casing 27 that are separated in the vehicle front-rear direction, and at a lower portion of the speed reduction portion casing 27 that is positioned below the front portion and the rear portion. Each cylindrical portion 27 c is connected to the outer ring member 15 via a connector 41. In order to facilitate understanding of the invention, in the overall view of FIG.

  Each connector 41 includes an outer cylinder member 42, an inner cylinder member 43, a bolt 44, and a rubber bush 45. The plurality of cylindrical portions 27c are arranged on the front side, the rear side, and the lower side when viewed from the axis O. The outer cylinder member 42 is fitted to the inner peripheral surface of each cylinder part 27c.

  As shown in FIG. 3, a cylindrical rubber bush 45 is passed through the inner periphery of the outer cylinder member 42. An inner cylinder member 43 is passed through the inner periphery of the rubber bush 45. The shaft portion of the bolt 44 is passed through the inner periphery of the inner cylinder member 43. Of these, the cylindrical portion 27c, the outer cylindrical member 42, the inner cylindrical member 43, and the bolt 44 are made of metal that cannot be elastically deformed, but only the rubber bush 45 is an elastic member. A male screw is formed on the outer periphery of the tip of the shaft portion of the bolt 44 and is screwed into a female screw hole formed in the outer ring member 15 as shown in FIG. By tightening the bolt 44, the inner cylinder member 43 is clamped between the head of the bolt 44 and the outer ring member 15, and the inner cylinder member 43 is coupled to the outer ring member 15 together with the bolt 44.

  As shown in FIG. 1, a rubber bush 45, which is an elastic member, is interposed between the motor part 31 and the wheel hub bearing part 11, and attaches the motor part 31 to the wheel hub bearing part 11 with an offset instead of being coaxial. That is, the axis P of the motor rotation shaft 32 is offset from the axis O of the wheel hub 12. As shown in FIG. 2, the contact surface 46 between the outer ring member 15 and the speed reduction unit casing 27 is preferably sealed with a seal member 47 over the entire circumference. The seal member 47 extends in the circumferential direction about the axis O.

  As shown in FIG. 1, a plurality of couplers 41 including rubber bushes 45 are arranged at intervals in the circumferential direction along a virtual circle centered on the axis P of the motor rotation shaft 32. As shown in FIG. 3, a meat steal 45s is formed between the outer peripheral surface and the inner peripheral surface of the rubber bush 45, a part of the cylindrical body in the circumferential direction is made thin, and the remaining part in the circumferential direction is made thick. The meat steal 45s may be a hole penetrating the rubber bush 45 in the axial direction, or may be a recess formed on the end surface of the rubber bush 45. The meat steal 45s is provided symmetrically with respect to the cylindrical center of the rubber bush 45. Thereby, the elastic coefficient of the rubber bush 45 is small in the direction E that penetrates the pair of meat steals 45s, and is increased in the direction F that penetrates the thick portion between the meat steals 45s. As shown in FIG. 1, each rubber bush 45 is attached in a posture that is thick in the radial direction and thin in the circumferential direction with respect to the axis O of the wheel hub 12.

  By the way, according to the present embodiment, the connector 41 has a cylindrical shape with the outer cylinder member 42 attached to the speed reduction unit casing 27, the bolt 44 and the inner cylinder member 43 attached to the outer ring member 15 and penetrating the cylindrical member. And a rubber bush 45 disposed in an annular gap between the outer cylinder member 42 and the inner cylinder member 43. The rubber bush 45 is interposed between the motor part casing 33 and the outer ring member 15 and is attached to the wheel hub bearing part 11 with the motor part 31 offset from the axis O of the wheel hub 12. As a result, the vibration and noise of the motor unit 31 are blocked by the rubber bush 45 and are not easily transmitted to the wheel hub bearing unit 11. Since the connecting portion 16 of the wheel hub bearing portion 11 is connected to the vehicle body via the suspension member 101, it is difficult for vibration and noise of the motor portion 31 to be transmitted to the vehicle body, and riding comfort performance is improved as compared with the conventional case.

  Further, according to the present embodiment, since the speed reduction part casing 27 is attached to the motor part casing 33, vibration and noise of the speed reduction part 21 are also blocked by the rubber bush 45, and are not easily transmitted to the wheel hub bearing part 11 and the vehicle body. . Therefore, riding comfort performance is improved as compared to the conventional case.

  Further, according to the present embodiment, a plurality of the rubber bushes 45 are arranged at intervals in the circumferential direction around the axis P of the motor rotation shaft 32, so that the vibration and noise of the motor unit 31 can be effectively blocked. Can do. In particular, even when the motor unit 31 vibrates about the axis P that is the center of the motor unit 31 as shown by a thick arrow in FIG. 1, the vibration is blocked by the rubber bush 45 and is not easily transmitted to the speed reduction unit 21 or the suspension member 101. Become. Further, even if the motor unit 31 vibrates in a direction perpendicular to the axis P, such vibration is blocked by the rubber bush 45 and is not easily transmitted to the speed reduction unit 21 or the suspension member 101.

  Further, according to the present embodiment, the rubber bush 45 is formed to be thick in the radial direction and thin in the circumferential direction with the axis O of the wheel hub 12 as the center. The elastic coefficient when elastically deforming in the circumferential direction as a center can be reduced, and the elastic coefficient when elastically deforming in the radial direction can be increased. Therefore, vibration and noise in the rotational direction of the wheel hub 12 can be effectively blocked.

  Next, an electric vehicle including the in-wheel motor drive device of this embodiment will be described. FIG. 4 is a plan view schematically showing the electric vehicle. Wheels 112 to 115 are attached to the vehicle body 111 of the electric vehicle. An in-wheel motor drive device 10 is disposed inside each of the wheels 112 to 115.

  First, the front wheel will be described. The in-wheel motor drive device 10 that drives the wheel 112 that becomes the left front wheel has a connector 51 at the front and a connector 52 at the rear. The basic structure of these couplers 51 and 52 is the same as the coupler 41 described above. Furthermore, the in-wheel motor drive device 10 has the same connector (not shown) in the lower part.

  The in-wheel motor drive device 10 that drives the wheel 113 that is the right front wheel also has the couplers 53 and 54, similarly to the wheel 112. When comparing the right and left front wheel connectors, the elastic coefficient of the rubber bush of the connector 53 is made larger than the elastic coefficient of the rubber bush of the connector 51. Further, the elastic coefficient of the rubber bush of the connector 54 is made larger than the elastic coefficient of the rubber bush of the connector 52. Or you may make it small conversely. By making the elastic coefficients of the rubber bushes different between the left and right wheels, the resonance frequency of the in-wheel motor drive device for the left and right wheels can be shifted, and vibration transmitted to the vehicle body can be reduced.

  Next, the rear wheel will be described. The in-wheel motor drive device 10 that drives the wheel 114 that becomes the left rear wheel has a connector 55 at the front and a connector 56 at the rear. The basic structure of these couplers 55 and 56 is the same as the coupler 41 described above. Furthermore, the in-wheel motor drive device 10 has the same connector (not shown) in the lower part.

  The in-wheel motor drive device 10 that drives the wheel 115 that becomes the right rear wheel also has the couplers 57 and 58 similarly to the wheel 114. Comparing the front wheel and rear wheel couplers, the distance from the axis O of the wheel hub bearing portion to the rubber bush of the coupler is large at the front wheel couplers 51 to 54 and small at the rear wheel couplers 55 to 58. The Alternatively, it may be reversed. By making the elastic coefficient of the rubber bush different between the front wheel and the rear wheel, the resonance frequency of the in-wheel motor drive device for the front and rear wheels can be shifted, and vibration transmitted to the vehicle body can be reduced.

  Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The in-wheel motor drive device according to the present invention is advantageously used in electric vehicles such as electric vehicles and hybrid vehicles.

10 in-wheel motor drive, 11 wheel hub bearing,
12 wheel hub, 12b shaft part, 12c tube part,
12d internal gear, 13, 14 rolling element, 15 outer ring member,
16 connecting portion, 17 bearing, 18 inner ring member,
21 Reduction part, 22 Shaft part, 23, 24 External gear,
25, 26 Rolling bearings, 27 Reduction part casing, 27c Tube part,
31 motor part, 32 motor rotating shaft, 33 motor part casing,
34 external gear, 41 coupling tool, 42 outer cylinder member,
43 inner cylinder member, 44 bolt (shaft member), 45 rubber bush,
46 contact surface, 47 seal member, 51-58 connector,
101 suspension member, 111 vehicle body,
112-115 wheels, O, P, Q axes.

Claims (7)

A wheel hub bearing that rotatably supports the wheel hub;
A connecting portion provided on the wheel hub bearing portion and connected to the vehicle body side member;
A motor unit for driving the wheel hub;
An elastic member interposed between the motor part and the wheel hub bearing part, and a coupling tool that is attached to the wheel hub bearing part by offsetting the axis of the motor rotation shaft of the motor part from the axis of the wheel hub, In-wheel motor drive device.   The in-wheel motor drive device according to claim 1, further comprising a speed reduction unit attached to the motor unit and configured to decelerate an output of the motor unit and transmit the output to the wheel hub.   3. The in-wheel motor drive device according to claim 1, wherein a plurality of the elastic members are arranged at intervals in a circumferential direction around a motor rotation axis of the motor unit.   4. The in-wheel motor drive device according to claim 3, wherein the plurality of elastic members are formed to be thick in a radial direction and thin in a circumferential direction around an axis of the wheel hub. The connector further includes an outer cylinder member attached to one of the motor portion and the wheel hub bearing portion, and a shaft member attached to the remaining other and penetrating the outer cylinder member,
The in-wheel motor drive device according to claim 1, wherein the elastic member has a cylindrical shape and is disposed in an annular gap between the outer cylinder member and the shaft member. A plurality of the in-wheel motor drive devices according to any one of claims 1 to 5, wherein the in-wheel motor drive devices are respectively provided on a plurality of wheels arranged separately in a vehicle width direction or a vehicle front-rear direction.
An electric vehicle in which an elastic coefficient of the elastic member is different for each in-wheel motor drive device. A plurality of the in-wheel motor drive devices according to any one of claims 1 to 5, wherein the in-wheel motor drive devices are respectively provided on a plurality of wheels arranged separately in a vehicle width direction or a vehicle front-rear direction.
An electric vehicle in which a distance from an axis of the wheel hub bearing portion to the elastic member is different for each in-wheel motor drive device.

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