JP2016014423A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress internal vibration of an in-wheel motor drive device.SOLUTION: A bearing (64) rotatably supporting a wheel-side rotary member (28) of the in-wheel motor drive device (21) to a casing-side member (45) is a rolling bearing including an outer ring and multiple rolling elements, where a buffer member (65) formed of a high polymer material is interposed between the outer ring of the bearing (64) and the casing-side member.

Description

  The present invention relates to a bearing that rotatably supports a rotating element, for example, a shaft, of an in-wheel motor drive device.

  As a conventional in-wheel motor drive device, for example, a device described in JP 2013-148198 A (Patent Document 1) is known. The in-wheel motor drive apparatus of patent document 1 is arrange | positioned inside the wheel of an electric vehicle, and is provided with the cycloid reducer which is compact and can obtain a high reduction ratio. Referring to the longitudinal sectional view of FIG. 7 showing a conventional in-wheel motor drive device, the rotor 111 of the electric motor 110 is rotatably supported by a bearing 112. The input shaft 121 of the speed reducer 120 is rotatably supported by a bearing 122. A pair of annular plates 123 for extracting the output rotation of the speed reducer 120 are rotatably supported by bearings 124, respectively.

JP 2013-148198 A

  However, the present inventor has found that there is a point to be further improved in the conventional in-wheel motor driving device. That is, the input shaft 121 is provided with a pair of eccentric shaft portions 125 eccentrically. The pair of eccentric shafts 125 are provided with a 180 ° phase change in order to cancel vibrations generated by the centrifugal force due to the eccentric motion, but the eccentric shafts 125 are arranged at a high speed around the rotation axis of the input shaft 121. The present inventor has found that the vibration due to the processing error cannot be completely cancelled and the input shaft 121 may be vibrated when it is revolved. The vibration of the input shaft 121 is transmitted to the casing 129 through the bearing 122, the annular plate 123, the bearing 124, the internal gear 126, and the support pin 127 in order. For this reason, each member of an in-wheel motor drive device vibrates including the casing 129 which makes the outline of an in-wheel motor drive device. Then, there is a concern that when the vibration of the electric vehicle is transmitted, the ride comfort is impaired, or abnormal noise is generated due to the vibration. Although not shown, there is a concern that the screwing portion for screwing the component to the in-wheel motor drive device may be loosened.

  In the in-wheel motor drive device as well as the cycloid reducer adopted in Patent Document 1, vibration of a rotating element that rotates at high speed inside the in-wheel motor drive device is transmitted to the casing of the in-wheel motor drive device. It is desirable to reduce as much as possible.

  In view of the above circumstances, an object of the present invention is to reduce transmission of internal vibrations of an in-wheel motor drive device to a casing that forms an outline of the in-wheel motor drive device.

  For this purpose, the in-wheel motor drive device according to the first invention comprises a motor section for driving the motor side rotating member, and a speed reducing section for decelerating the rotation of the motor side rotating member and outputting it to the wheel side rotating member. The bearing that rotatably supports the side rotating member on the casing side member and / or the bearing that rotatably supports the wheel side rotating member on the casing side member is a rolling bearing including an outer ring and a plurality of rolling elements. A buffer member made of a polymer material is interposed between the casing side member and the casing side member.

  The in-wheel motor drive device according to the second invention includes a motor unit that drives the motor-side rotation member, and a reduction unit that decelerates the rotation of the motor-side rotation member and outputs it to the wheel-side rotation member. The bearing that rotatably supports the casing side member and / or the bearing that rotatably supports the wheel side rotating member on the casing side member is a rolling bearing including an inner ring and a plurality of rolling elements. A buffer member made of a polymer material is interposed between the penetrating motor-side rotating member and / or the wheel-side rotating member.

  According to the first and second aspects of the present invention, the rotating member inside the in-wheel motor driving device such as the motor-side rotating member and the wheel-side rotating member, the casing of the non-rotating member that forms the outline of the in-wheel motor driving device, and the rotating member In the support relationship with the rolling bearing that supports the casing, since the buffer member made of a polymer material is interposed between the rotating member and the casing, the buffer member absorbs vibration and the vibration of the rotating member is transmitted to the casing. Can be reduced.

  According to the first and second inventions, since the buffer member made of a polymer material is interposed between the outer ring or inner ring of the bearing and the counterpart member to which the inner and outer rings are attached, such as the casing or the rotating member, the bearing When the coefficient of thermal expansion differs from that of the mating member, the buffer member is designed to absorb the difference in thermal expansion between the inner / outer ring and the mating member. Therefore, regardless of the temperature change, the fitting state of the inner / outer ring and the mating member, for example, the contact surface pressure, can be kept within a predetermined range and creep can be prevented.

  As an example, the rolling bearing has both an inner ring that is a member different from the rotating member and an outer ring that is a member different from the casing side member. Alternatively, as another example, the inner ring may be integrally formed with the rotating member rather than as a separate member. Alternatively, as still another example, the outer ring may be integrally formed with the casing side member, not as a separate member.

  The casing-side member may be a member attached to the casing in addition to the casing that forms the outline of the in-wheel motor drive device, or a rolling bearing regardless of whether it is a non-rotating fixed member or a rotating member. Any member may be used as long as it is closer to the casing.

  As one embodiment of the present invention, the motor-side rotating member is a part of the motor unit, and a motor rotating shaft that outputs rotation from the motor unit, and a speed reducing unit that is part of the speed reducing unit and inputs rotation to the speed reducing unit The buffer member is provided on a bearing that rotatably supports the motor rotation shaft on the casing side member. As another embodiment, the buffer member is provided in a bearing that rotatably supports the speed reducing portion input shaft on the casing side member.

  The shape, size, and number of the buffer members made of the polymer material are not particularly limited. As one embodiment of the present invention, the buffer member is an annular body extending along the inner peripheral surface of the inner ring or the outer peripheral surface of the outer ring. According to this embodiment, since the buffer member is provided over the entire circumference of the inner ring or the outer ring, transmission of vibration can be effectively reduced. The axial width dimension and the radial thickness dimension of the annular body are not particularly limited. The annular body is a strip-like body such as an endless band. It is preferable that the axial width dimension of the annular body is constant regardless of the circumferential position. The radial thickness of the annular body is also preferably constant regardless of the circumferential position. As another embodiment, the buffer member may be provided on the rolling bearing with an interval in the circumferential direction.

  The buffer member made of a polymer material is basically a resin, and the higher the performance of absorbing and attenuating vibrations input to the buffer member, the better. Further, since the buffer member is used for a bearing, it is desired that the buffer member has high oil resistance and is hardly deteriorated even if it is exposed to lubricating oil for a long time. Further, since the buffer member is provided inside the in-wheel motor drive device, it is desired that the buffer member has high heat resistance and does not deteriorate even at a high temperature of 150 ° C. As a preferred embodiment of the present invention, the buffer member is an elastic body mainly composed of a fluorine polymer material or an acrylic polymer material. According to this embodiment, the oil resistance and heat resistance of the buffer member can be ensured. Examples of the elastic body using a fluorine-based polymer material include fluorine rubber and fluorosilicone rubber. Examples of the elastic body mainly composed of an acrylic polymer material include acrylic rubber. In another embodiment, the buffer member may be made of other types of polymer materials.

  The casing-side member of the present invention may be a non-rotating fixed member or a rotating member. As one embodiment of the present invention, the motor-side rotating member is coaxially arranged with the wheel-side rotating member, and a circular recess that receives the end of the motor-side rotating member is formed at the end of the wheel-side rotating member. The bearing that rotatably supports the motor-side rotating member on the casing-side member is installed in an annular space defined between the inner peripheral surface of the circular recess and the outer peripheral surface of the motor-side rotating member, and includes a buffer member.

  As one embodiment of the present invention, the speed reducing portion is eccentrically provided on the motor-side rotating member, and the motor-side rotating member is held by the rotation of the motor-side rotating member that is held by the eccentric portion so as to be relatively rotatable. A pair of revolving members that revolve around the axis of the outer periphery, an outer peripheral engagement member that engages with the outer periphery of the revolving member to cause the revolving motion of the revolving member, and the rotational movement of the revolving member of the motor side rotating member. And a motion conversion mechanism that converts the rotational motion about the axis to the wheel-side rotating member. According to this embodiment, vibration generated from the inside of the cycloid reduction gear can be reduced. As another embodiment, the reduction gear may be another gear set.

  As described above, according to the present invention, in the in-wheel motor drive device, it is possible to reduce the vibration generated from the rotating member inside the speed reducing portion. Therefore, riding comfort performance is improved in an electric vehicle or a hybrid vehicle equipped with an in-wheel motor drive device. Further, there is no problem caused by vibration, and the durability of the in-wheel motor drive device is improved.

It is a longitudinal cross-sectional view which shows the in-wheel motor drive device which becomes one Embodiment of this invention. It is a cross-sectional view in II-II of FIG. It is a longitudinal cross-sectional view which expands and shows the deceleration part in FIG. It is a longitudinal cross-sectional view which takes out and shows the rolling bearing which attached the buffer member. It is a longitudinal cross-sectional view which shows other embodiment of this invention, and expands and shows the deceleration part of an in-wheel motor drive device. It is a longitudinal cross-sectional view which shows other embodiment of this invention, and expands and shows the motor part of an in-wheel motor drive device. It is a longitudinal cross-sectional view which shows the conventional in-wheel motor drive device.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an in-wheel motor drive device according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is an enlarged longitudinal sectional view showing the speed reducing portion in FIG. 4 is a longitudinal sectional view showing the rolling bearing in FIG. The in-wheel motor drive device 21 includes a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, and a wheel hub bearing unit C that transmits the output from the deceleration unit B to driving wheels. With.

  The motor part A has a motor casing 22a that forms an outer shell of the motor part, a pump casing 22p, and a motor cover 22t, and the speed reducing part B has a speed reducing part casing 22b that forms the outer shell of the speed reducing part. The motor casing 22a, the pump casing 22p, the motor cover 22t, and the speed reducer casing 22b are coupled to each other by a bolt or the like or integrally formed to constitute one casing 22. Then, the outer ring member 33 a of the wheel hub bearing portion C is attached and fixed to the casing 22. The in-wheel motor drive device 21 is attached, for example, in a wheel housing of an electric vehicle. This electric vehicle is a passenger car and can travel on public roads like a general engine car.

  The motor part A includes a stator 23 fixed to the inner periphery of a cylindrical motor casing 22a, a rotor 24 disposed at a position facing the inner side of the stator 23 via a gap opened in the radial direction, and an inner side of the rotor 24. A radial gap motor including a motor rotating shaft 35 that is connected and fixed to the rotor 24 and rotates integrally with the rotor 24. Alternatively, although not shown, the motor part A may be an axial gap motor.

  The motor casing 22a extends about the axis O of the motor rotation shaft 35 in the axial direction. The pump casing 22p which is a part of the casing 22 is a substantially disc-shaped partition wall, which forms a boundary with the speed reduction part B at one end in the axis O direction of the motor part A, and a motor via a rolling bearing 37. One end of the rotating shaft 35 is rotatably supported. Further, the pump casing 22p includes an oil pump 51. The motor cover 22t which is a part of the casing 22 has a substantially disc shape, and forms an end surface of the motor part A at the other end in the axis O direction of the motor part A, and a motor rotating shaft 35 via a rolling bearing 36. The other end of this is rotatably supported. The motor cover 22t is an end portion of the motor part A and also an end portion of the in-wheel motor drive device 21.

  One end of the motor rotating shaft 35 is coupled to a speed reducing portion input shaft 25 that is rotatably provided inside the speed reducing portion B. This coupling is serration fitting, and the tapered speed reduction portion input shaft 25 is inserted and fixed in the end opening of the motor rotation shaft 35 formed in a tubular shape.

  The speed reduction part B is a cycloid speed reducer, and is coaxially arranged on one side in the axis O direction of the motor part A, and has a cylindrical speed reduction part casing 22b and an outer pin holding part 45 attached and fixed to the speed reduction part casing 22b. As a revolving member that is rotatably held by the decelerating portion input shaft 25 extending along the axis O, a pair of eccentric portions 25a and 25b formed on the decelerating portion input shaft 25, and the eccentric portions 25a and 25b. A pair of curved plates 26a, 26b, a plurality of outer pins 27 as outer peripheral engagement members that engage with the outer peripheral portions of the curved plates 26a, 26b, a speed reduction portion output shaft 28 extending along the axis O, and a speed reduction portion output The curved plate 26a, 26b is attached to the inner pin 31 as an inner engagement member that couples with the shaft 28 and extracts the rotational movement of the curved plates 26a, 26b, and the curved plate 26a, 26b. Contact with the end face of 6b the center collar 29 to prevent the inclination of the curved plates, and a reinforcing member 61.

  The speed reduction unit input shaft 25 extends along the axis O of the motor rotation shaft 35, and the end of the speed reduction unit input shaft 25 on the side closer to the motor unit A of both ends thereof is coupled to one end of the motor rotation shaft 35. . The end of the speed reduction part input shaft 25 on the side far from the motor part A is rotatably supported by the end of a speed reduction part output shaft 28 described later via a rolling bearing 39. A pair of eccentric portions 25 a and 25 b are formed eccentrically from the axis O on the outer periphery of the deceleration portion input shaft 25. The speed reduction part input shaft 25 is rotatably supported by the rolling bearing 38 on the side closer to the motor part A than the eccentric parts 25a and 25b.

  The two pairs of eccentric parts 25a and 25b have a disk shape and are spaced apart from each other in the direction of the axis O. In order to cancel vibrations generated by the centrifugal force due to the eccentric motion, the circumferential direction has a 180 ° phase. It is provided by changing. The motor rotation shaft 35 and the speed reduction part input shaft 25 constitute a motor side rotation member that transmits the driving force of the motor part A to the speed reduction part B.

  Referring to FIG. 2, curved plate 26b has a disc shape, and its outer peripheral portion is formed in a waveform. Specifically, the outer peripheral portion of the curved plate 26 b is a plurality of curved concave portions formed of a trochoidal curve such as an epitrochoid and recessed in the radial direction, and meshes with the outer pin 27. The curved plate 26b has a plurality of through holes 30a and 30b penetrating from one end face to the other end face. A plurality of through holes 30a are provided at equal intervals on the circumference centering on the rotation axis X of the curved plate 26b, and receive the inner pins 31. Moreover, the through-hole 30b is provided in the autorotation axis X of the curved plate 26b, and becomes an inner periphery of the curved plate 26b. The curved plate 26b is attached to the outer periphery of the eccentric portion 25b so as to be relatively rotatable. The inner pin 31 includes a needle roller bearing, and includes an inner pin main body 31a, a plurality of needle rollers 31b, and a bearing outer ring 31c. The inner pin main body 31a passes through the bearing outer ring 31c, and the needle rollers 31b are disposed in an annular space between the inner pin main body 31a and the bearing outer ring 31c. The outer peripheral surface of the bearing outer ring 31c is in rolling contact with the hole wall surface of the through hole 31a.

  The curved plate 26b is rotatably supported by the rolling bearing 41 with respect to the eccentric portion 25b. In order to facilitate understanding, a part of the rolling bearing 41 in the circumferential direction is shown in FIG. The rolling bearing 41 includes a plurality of rollers 44 disposed between an annular inner ring member 42 having an inner raceway surface 42a on the outer diameter surface and a hole wall surface of the through-hole 30b serving as the outer raceway surface. And a cylindrical roller bearing provided with a cage (not shown) that holds the interval between the rollers 44 adjacent in the circumferential direction. Alternatively, it may be a deep groove ball bearing. The inner diameter surface of the inner ring member 42 is fitted to the outer diameter surface of the eccentric portion 25b. The inner ring member 42 further includes a hole 43 that is located on the inner raceway surface 42a and penetrates in the radial direction and a pair of flanges that face each other across the inner raceway surface 42a. The hole 43 connects the inside of the eccentric portion 25b to a branch oil passage 58b extending in the direction perpendicular to the axis O. The same applies to the curved plate 26a.

  A plurality of outer pins 27 are provided at equal intervals on a circumferential track centered on the axis O of the motor-side rotating member (see FIG. 2), and extend parallel to the axis O. When the two pair of curved plates 26a, 26b revolve around the axis O, the curved concave portions on the outer periphery of the curved plates 26a, 26b engage with the outer pin 27, and the curved plates 26a, 26b rotate. Give rise to

  The outer pin 27 disposed inside the speed reduction unit casing 22b may be directly connected and fixed to the inner wall surface of the speed reduction unit casing 22b, but is preferably attached and fixed to the inner wall surface of the speed reduction unit casing 22b. It is held by the outer pin holding part 45. More specifically, as shown in FIG. 3, both axial ends of the outer pin 27 are rotatably supported by needle roller bearings 27 a (rolling bearings) attached to the outer pin holding portion 45. In this way, by attaching the outer pin 27 to the outer pin holding portion 45 via the rolling bearing so as to be rotatable and rotatable, the contact resistance due to the engagement with the curved plates 26a and 26b can be reduced. Although described in detail later, in addition to the outer pin holding portion 45, the speed reduction portion output shaft 28, the reinforcing member 61, and the casing 22 may be collectively referred to as a casing side member.

  In all the embodiments described above, the cylindrical outer pin holding part 45 attached and fixed to the speed reduction part casing 22b is provided separately from the inner wall surface of the speed reduction part casing 22b, but is not limited thereto. Although not shown, as an alternative, the outer wall surface of the outer pin holding portion 45 may be in close contact with the inner wall surface of the speed reduction portion casing 22b. Or although not illustrated, the outer pin holding | maintenance part 45 may be integrally formed in the deceleration part casing 22b.

  Referring to FIG. 3, outer pin holding portion 45 has a cylindrical shape, and axial center portion 45c of outer pin holding portion 45 has a larger diameter than axial end portions 45a and 45b on both ends. The outer pin 27 is disposed in an annular space between the small-diameter axial ends 45a and 45b and the large-diameter axial central portion 45c. Further, the outer pin holding portion 45 has curved plates 26a, 26b, ends of the speed reduction portion output shaft 28, inner pins 31, eccentric portions 25a, 25b, speed reduction portion input shaft 25 on the inner diameter side of the axial ends 45a, 45b. The end of the is housed. The outer pin holding portion 45 is brought into a floating state when viewed from the speed reduction portion casing 22b, and the outer peripheral surface of the outer pin holding portion 45 is separated from the inner wall surface of the speed reduction portion casing 22b. However, the outer pin holding portion 45 is attached and fixed to the speed reduction portion casing 22b by a fixing means such as a bolt or a key so as not to be relatively rotatable. As described above, the outer pin holding portion 45 is a non-rotating fixed member and is a casing side member on the speed reduction portion casing 22b side as viewed from the speed reduction portion output shaft 28. From the viewpoint of reducing the weight of the in-wheel motor drive device 21, the casing 22 including the speed reduction portion casing 22b is formed of a light metal such as an aluminum alloy or a magnesium alloy. On the other hand, it is desirable to form the outer pin holding part 45, which requires high strength, from carbon steel. An annular center collar 29 is disposed between the two curved plates 26a and 26b. The center collar 29 prevents the curved plates 26a and 26b from being inclined with respect to the axis O.

  The speed reduction part output shaft 28 has a large-diameter flange part 28b at the end part on the motor part A side and a shaft part 28d on the wheel hub bearing part C side. A small-diameter flange portion 28c is formed at a connection portion between the large-diameter flange portion 28b and the shaft portion 28d. A circular recess 34 is formed in the center of the large-diameter flange portion 28b to receive one end of the speed reducer input shaft 25. A rolling bearing 39 is disposed on the inner peripheral surface of the circular recess 34.

  In the outer edge portion of the large diameter flange portion 28b, holes for fixing one end portion of the inner pin 31 are formed at equal intervals on the circumference around the axis O of the speed reduction portion output shaft 28. The wheel hub 32 of the wheel hub bearing portion C is connected and fixed to the outer peripheral surface of the shaft portion 28d (see FIG. 1).

  As shown in FIG. 3, a reinforcing member 61 is provided at the other end of the inner pin 31 on the side away from the large-diameter flange portion 28b. The reinforcing member 61 is a flange-shaped large-diameter disc portion 61b that is coupled and fixed to the tips of the plurality of inner pins 31 inside the speed reduction portion B, and is coaxially formed adjacent to the large-diameter disc portion 61b. A small-diameter disk part 61c having a smaller diameter than the part 61b and a smaller-diameter cylindrical part 61d extending from the inner peripheral edge of the small-diameter disk part 61c to the motor part A are included. The cylindrical portion 61d has a shape extending along the axis O, whereas the large-diameter disc portion 61b and the small-diameter disc portion 61c are disc portions that are integrally formed and spread in the direction perpendicular to the axis O.

  The load applied to a part of the inner pins 31 from the two curved plates 26a, 26b is applied to all the inner pins via the large-diameter disk portion 61b of the reinforcing member 61 and the large-diameter flange portion 28b of the reduction portion output shaft 28. Since it is supported by 31, the stress which acts on the inner pin 31 can be reduced and durability can be improved. The tip of the cylindrical portion 61d is inserted into the oil pump 51 to drive the oil pump 51 (see FIG. 1). A rolling bearing 38 is disposed on the inner peripheral surface of the small-diameter disc portion 61c, and the rolling bearing 38 supports the speed reduction portion input shaft 25 in a freely rotatable manner.

  Since the reinforcing member 61 is connected to the speed reducing unit output shaft 28 via the inner pin 31, the reinforcing member 61 rotates integrally with the speed reducing unit output shaft 28. As shown in FIG. 1, the speed reducer output shaft 28, the reinforcing member 61, and the wheel hub 32 are wheel-side rotating members that transmit the driving force of the speed reducer B to drive wheels (drive wheels (not shown) connected to the bolts 32 c). Configure.

  Except for the end of the speed reducer input shaft 25 that is serrated to the motor rotation shaft 35, most of the speed reducer input shaft 25 is in the axial direction from the annular reinforcing member 61 to the small-diameter flange portion 28c of the speed reducer output shaft 28. Match the position. The speed reducer input shaft 25 is disposed inside the reinforcing member 61 and in the circular recess 34, and is rotatably supported by the speed reducer output shaft 28 via the rolling bearing 39 on one end side, and the rolling bearing on the other end side. It is rotatably supported by the reinforcing member 61 via 38.

  Metal rolling bearings 62 and 64 are disposed at both ends of the outer pin holding portion 45. The rolling bearings 62 and 64 rotatably support the wheel side rotating member. The rolling bearing 62 is disposed on the side close to the motor part A, and the rolling bearing 64 is disposed on the side close to the wheel hub bearing part C.

  As shown in FIG. 3, the outer ring 62 a of the rolling bearing 62 is attached to the inner peripheral surface of the axial end portion 45 a of the outer pin holding portion 45 so as not to be relatively rotatable, and the inner ring 62 b of the rolling bearing 62 is a small-diameter circle of the reinforcing member 61. It is attached to the outer peripheral surface of the plate part 61c so as not to be relatively rotatable. The plurality of rolling elements 62c are arranged in an annular space between the outer ring 62a and the inner ring 62b. The plurality of rolling elements 62c are held at equal intervals in the circumferential direction by a holder (not shown). The outer peripheral surface of the large-diameter disc portion 61b and the outer peripheral surface of the small-diameter disc portion 61c constitute an annular step. The rolling bearing 62 is housed in an annular step between the large-diameter disk portion 61b and the small-diameter disk portion 61c, and is disposed at the same radial position as the inner pin 31. A buffer member 63 is interposed between the outer ring 62 a and the outer pin holding portion 45. The buffer member 63 is an annular body provided along the outer peripheral surface of the outer ring 62a. In the present embodiment, two buffer members 63 are provided with an interval in the direction of the axis O.

  The outer ring 64a of the rolling bearing 64 is attached to the inner peripheral surface of the axial end portion 45b of the outer pin holding portion 45 so as not to be relatively rotatable, and the inner ring 64b of the rolling bearing 64 is an outer peripheral surface of the small-diameter flange portion 28c of the speed reduction unit output shaft 28. It is attached so that relative rotation is impossible. The plurality of rolling elements 64c are arranged in an annular space between the outer ring 64a and the inner ring 64b. The plurality of rolling elements 62c are held at equal intervals in the circumferential direction by a holder (not shown). The outer peripheral surface of the large-diameter flange portion 28b and the outer peripheral surface of the small-diameter flange portion 28c constitute an annular step. The rolling bearing 64 is housed in an annular step between the large-diameter flange portion 28 b and the small-diameter flange portion 28 c and is disposed at the same radial position as the inner pin 31. A buffer member 65 is interposed between the outer ring 64 a and the outer pin holding portion 45. The two buffer members 65 are annular bodies provided along the outer peripheral surface of the outer ring 64a.

  Since the rolling bearings 62 and 64 have the same configuration and the buffer members 63 and 65 have the same configuration, the buffer member 63 will be described as a representative of the buffer members 63 and 65. FIG. 4 is a longitudinal sectional view showing the rolling bearing 62 with the buffer member 63 attached. A plurality of annular grooves 62d are formed on the outer peripheral surface of the outer ring 62a. An annular buffer member 63 serving as a resin band is fitted into the annular groove 62d. In a state where the outer ring 62a is removed from the counterpart material (axial end 45a), the buffer member 63 rises from the annular groove 62d without receiving a compressive force from the axial end 45a. On the other hand, when the outer ring 62a is attached to the axial end portion 45a, the buffer member 63 is elastically deformed by receiving a compressive force from the inner peripheral surface of the axial end portion 45a, and fits inside the annular groove 62d.

  Referring to FIG. 3, an annular groove is not formed on the inner peripheral surface of the axial end portion 45 a of the outer pin holding portion 45, and it remains a cylindrical surface. Alternatively, although not illustrated, as a modification, an annular groove may be provided on the inner peripheral surface of the axial end portion 45a, and the outer peripheral surface of the outer ring 62a may be a cylindrical surface.

  The width dimension of the buffer member 63 measured in the axial direction is a predetermined value included in 1.0 to 5.0 [mm] in a natural state where no load is applied, and is constant over the entire circumference. If the width dimension is smaller than 1.0 [mm], the moldability of the buffer member 63 is deteriorated. When the width dimension is larger than 5.0 [mm], the processing amount of the annular groove 62d becomes large.

  The thickness dimension of the buffer member 63 measured in the radial direction is a predetermined value included in 1.0 to 3.0 [mm] in a natural state where no load is applied, and is constant over the entire circumference. If the thickness dimension is smaller than 1.0 [mm], the moldability of the buffer member 63 is deteriorated. When the thickness dimension is larger than 3.0 [mm], the processing amount of the annular groove 62d is increased.

  When the buffer member 63 receives a compressive force, the vibration damping effect of the buffer member 63 is reduced. Therefore, the width dimension and the diameter dimension of the buffer member 63 are calculated so that the surface pressure acting on the buffer member 63 from the outer ring 62a is equal to or less than a predetermined value over the entire operating temperature range of the in-wheel motor drive device 21. Furthermore, the width dimension and the thickness dimension of the buffer member 63 are determined in consideration of the fitting state between the outer ring 62a and the mating member to which the outer ring 62a is attached and the difference in thermal expansion. The counterpart member of the outer ring 62a is the outer pin holding portion 45. For example, when the outer ring 62a and the outer pin holding part 45 are made of steel, the difference in thermal expansion between them is small. For this reason, the buffer member 63 is not crushed by receiving an excessive compressive force at a high temperature, and the vibration damping effect is not lowered.

  However, for example, when the outer ring 62a is made of steel and the outer pin holding portion 45 is made of a light metal such as aluminum, the difference in thermal expansion between the two is large. The tightening allowance of 45 will fall. Therefore, when the thermal expansion difference between the two is large, the width dimension and the thickness dimension of the buffer member 63 are calculated in consideration of the thermal expansion difference so that the interference does not change at high temperatures.

  The buffer members 63 and 65 are elastic bodies mainly composed of a fluorine polymer material or an acrylic polymer material. Specifically, it is made of, for example, fluororubber, fluorosilicone rubber, acrylic rubber, and the like, and is excellent in oil resistance and heat resistance and has a large damping rate with respect to vibration as compared with other rubber materials. On the other hand, the motor side rotating member, the wheel side rotating member, and the casing side member are made of metal. The rolling bearings 36, 37, 38, 39, 62, 64 are also made of metal.

  Referring to FIG. 1, an oil pump 51 is connected to an intake oil passage 52 and a discharge oil passage 54 provided in the wall of the pump casing 22p, and is provided with an intake oil from an oil tank 53 provided at a lower portion of the speed reduction unit B. The lubricating oil is sucked through the passage 52 and discharged from the discharge oil passage 54. The discharge oil passage 54 is provided in the motor part A to cool the lubricating oil 55 (inside the wall of the motor casing 22a), a communication oil passage 56 provided in the wall of the motor cover 22t, and a tubular oil passage An axial oil passage 57 provided inside the motor rotation shaft 35 and the speed reduction part input shaft 25 and extending along the axis O, and a branching oil extending from the axis O toward the radially outer side from the axis O by the speed reduction part B A branch oil passage 58b that similarly extends in the passage 58a and the eccentric portion 25b, a hole 43 (see FIG. 2) drilled in the inner ring member 42 fitted to the outer periphery of each of the eccentric portions 25a and 25b, and the axial oil passage 57 The oil passage 58c opened at the tip is sequentially connected.

  The lubricating oil discharged from the oil pump 51 flows through these oil passages 54, 55, 56, 57, 58 a (58 b), 58 c and the hole 43 in order, and the inside of the reduction part B (rolling bearings 38, 39, 41, 62). 64, curved plates 26a and 26b, inner pin 31, outer pin 27, etc.) are lubricated. The lubricating oil after lubrication falls and collects in the oil tank 53. Then, it is sucked again by the oil pump 51 and circulates inside the in-wheel motor drive device 21. As described above, the in-wheel motor drive device 21 according to the present embodiment includes an axial center-lubricated lubricating oil circuit and injects lubricating oil from the speed reduction unit input shaft 25. Then, the lubricating oil flows radially outward from the speed reducer input shaft 25 and lubricates the speed reducer B. The lubricating oil branches off from the axial oil passage 57 and flows through a rotor oil passage 59 formed in the rotor 24 to cool the inside of the motor part A and lubricate the rolling bearings 36 and 37.

  The wheel hub bearing portion C is a rolling bearing having an inner ring 33c, a wheel hub 32 as a rotating shaft, a rolling element 33, and an outer ring member 33a. As shown in FIG. 1, the wheel hub 32 is coaxially arranged on one side in the direction of the axis O of the speed reduction unit output shaft 28 and is connected and fixed to the speed reduction unit output shaft 28. The outer ring member 33 a is fixed to one end of the speed reduction unit casing 22 b with a bolt 33 b, and the inner ring 33 c is fitted and fixed to the outer peripheral surface of the wheel hub 32. The wheel hub bearing portion C is a double row angular contact ball bearing having a large number of rolling elements 33 in a double row, and is arranged between the outer ring member 33a and the inner ring 33c on the side where the rolling elements 33 in the first row are close to the speed reduction portion B. The second row of rolling elements 33 is disposed between the outer ring member 33 a and the wheel hub 32 on the side far from the speed reduction portion B.

  The wheel hub 32 includes a cylindrical hollow portion 32a and a wheel mounting flange portion 32b that protrudes from one end of the hollow portion 32a in the outer diameter direction. The shaft portion 28d is fitted in the central hole of the hollow portion 32a. An inner raceway surface that is in rolling contact with the second row of rolling elements 33 is formed on the outer peripheral surface of the hollow portion 32a. A drive wheel road wheel (not shown) is connected and fixed to the wheel mounting flange portion 32b by a bolt 32c.

  The operation principle of the in-wheel motor drive device 21 having the above configuration will be described in detail.

  The motor unit A receives, for example, an electromagnetic force generated by supplying an alternating current to the coil of the stator 23, and the rotor 24 composed of a permanent magnet or a magnetic material rotates.

  Thereby, when the motor rotating shaft 35 connected to the rotor 24 rotates, the curved plates 26a and 26b revolve around the axis O of the motor side rotating member. At this time, the outer pin 27 is engaged with the curved concave portions formed on the outer circumferences of the curved plates 26a and 26b while rolling, and rotates the curved plates 26a and 26b in the direction opposite to the rotation of the motor side rotating member. Exercise.

  The inner pin 31 inserted through each through hole 30a is sufficiently thinner than the inner diameter of the through hole 30a, and abuts against the hole wall surface of the through hole 30a as the curved plates 26a and 26b rotate (see FIG. 2). As a result, the revolving motion of the curved plates 26a and 26b is not transmitted to the inner pin 31, but only the rotational motion of the curved plates 26a and 26b is transmitted to the wheel hub bearing portion C via the speed reduction portion output shaft 28. The bearing outer ring 31c of the inner pin 31 rolls along the hole wall surface of the through hole 30a. At this time, a part of the bearing outer ring 31c is in contact with the hole wall surface of the through hole 30a, and the remaining part of the bearing outer ring 31c is not in contact with the hole wall surface of the through hole 30a. The bearing outer ring 31c is in rolling contact with the hole wall surface of the through hole 30a while repeating a contact state and a non-contact state.

  At this time, the speed reduction part output shaft 28 arranged coaxially with the axis O takes out the rotation of the curved plates 26 a and 26 b as the output axis of the speed reduction part B. As a result, the rotation of the speed reduction unit input shaft 25 is decelerated by the speed reduction unit B and transmitted to the speed reduction unit output shaft 28. Therefore, even when the low torque, high rotation type motor unit A is employed, it is necessary for the drive wheels. Torque can be transmitted.

Note that the reduction ratio of the speed reduction unit B having the above-described configuration is calculated as (Z _A −Z _B ) / Z _B where Z _{A is} the number of outer pins 27 and Z _B is the number of waveforms of the curved plates 26a and 26b. The In the embodiment shown in FIG. 2, since Z _A = 12 and Z _B = 11, the reduction ratio is 1/11, and a very large reduction ratio can be obtained. In this way, by adopting the speed reduction unit B that can obtain a large speed reduction ratio without using a multi-stage configuration, the in-wheel motor drive device 21 having a compact and high speed reduction ratio can be obtained. By employing the in-wheel motor drive device 21 according to the present embodiment in an electric vehicle, the unsprung weight can be suppressed. As a result, an electric vehicle with excellent running stability can be obtained.

  In the present embodiment, two curved plates 26a and 26b of the deceleration unit B are provided with 180 ° phase shifts. However, the number of the curved plates can be arbitrarily set. In the case of providing a sheet, it is preferable to change the phase by 120 °. And it is good to prepare the center collar 29 of this embodiment two sheets, and to each provide between adjacent curved plates.

  Moreover, although the motion conversion mechanism in this embodiment showed the example comprised by the inner pin 31 fixed to the deceleration part output shaft 28, and the through-hole 30a provided in the curve boards 26a and 26b, Without limitation, any configuration capable of transmitting the rotation of the speed reduction unit B to the wheel hub 32 can be employed. For example, it may be a motion conversion mechanism composed of an inner pin fixed to a curved plate and a hole formed in the wheel side rotation member.

  The description of the operation in the present embodiment has been made by paying attention to the rotation of each member. However, in reality, power including torque is transmitted from the motor unit A to the drive wheels. Therefore, the power decelerated as described above is converted into high torque.

  In the description of the operation in the present embodiment, power is supplied to the motor unit A to drive the motor unit A, and the power from the motor unit A is transmitted to the drive wheels. When decelerating or going down a hill, the power from the driving wheel side may be converted into high-rotation and low-torque rotation by the deceleration unit B and transmitted to the motor unit A, and the motor unit A may generate power. . Furthermore, the electric power generated here may be stored in a battery, and the motor unit A may be driven later, or may be used for the operation of other electric devices provided in the vehicle.

  By the way, according to the in-wheel motor drive device 21 of the present embodiment, the motor part A that drives the motor rotation shaft 35 included in the motor side rotation member and the rotation of the motor side rotation member are decelerated and included in the wheel side rotation member. A rolling bearing 64 that includes a speed reducing portion B that outputs to the speed reducing portion output shaft 28 and rotatably supports the speed reducing portion output shaft 28 on an outer pin holding portion 45 included in the casing side member. It is a rolling bearing including the moving body 64c. Further, the rolling bearing 62 that rotatably supports the reinforcing member 61 included in the wheel side rotating member on the outer pin holding portion 45 is a rolling bearing including an outer ring 62a and a plurality of rolling elements 62c. Between the outer rings 62a and 64a and the outer pin holding portion 45, buffer members 63 and 65 made of a polymer material are interposed.

  The buffer members 63 and 65 made of a polymer material have a larger damping rate with respect to vibration than metal members, and even if the vibration of the speed reducer input shaft 25 included in the motor-side rotating member is transmitted to the rolling bearings 62 and 64, It is blocked and absorbed by the buffer members 63 and 65, and it is difficult for vibration to be transmitted to the outer pin holding portion 45 and the speed reduction portion casing 22b. Therefore, the vibration of the casing 22 is reduced as compared with the conventional in-wheel motor drive device shown in FIG.

  Thereby, even if the vibration of the speed reduction part input shaft 25 is input to the rolling bearings 62 and 64 via the speed reduction part output shaft 28, it is possible to suppress transmission of this vibration to the outer pin holding part 45. Therefore, vibrations of the outer pin holding part 45 and the casing 22 can be reduced.

  According to the in-wheel motor drive device 21 of the present embodiment shown in FIG. 3, the buffer members 63 and 65 are annular bodies that extend along the outer peripheral surfaces of the outer rings 62a and 64a. As described above, since the buffer member is provided over the entire circumference of the rolling bearings 62 and 64, the vibration in the speed reduction portion B can be effectively damped.

  The buffer members 63 and 65 of this embodiment are elastic bodies mainly composed of a fluorine-based polymer material or an acrylic polymer material. Thus, by using a resin band, oil resistance and heat resistance can be ensured.

  In addition, the speed reduction part B of the present embodiment is held eccentrically by the eccentric parts 25a and 25b provided eccentric to the motor side rotating member, and the eccentric parts 25a and 25b, and the motor side rotating member rotates with the rotation of the motor side rotating member. The curved plates 26a and 26b as revolving members that perform the revolving motion around the axis O of the motor-side rotating member, and the outer periphery that engages with the outer peripheries of the curved plates 26a and 26b and causes the curved plates 26a and 26b to rotate. An outer pin 27 as an engaging member, and an inner pin as a motion converting mechanism that converts the rotational motion of the curved plates 26a and 26b into a rotational motion around the axis O of the motor side rotating member and outputs it to the wheel side rotating member. 31 and a through hole 30a. Also when the deceleration part B is such a cycloid reduction gear, the vibration inside a reduction part can be suppressed.

  Although not shown in the drawings, as a modification of the embodiment shown in FIGS. 3 and 4, the buffer members 63 and 65 are not provided on the outer peripheral surfaces of the outer rings 62a and 64a, but are provided on the inner peripheral surfaces of the inner rings 62b and 64b. The buffer members 63 and 65 may be provided, and the buffer members may be interposed between the inner peripheral surfaces of the inner rings 62b and 64b and the outer peripheral surface of the wheel-side rotating member. Or you may provide a buffer member in both the outer peripheral surface of the outer rings 62a and 64a and the inner peripheral surface of the inner rings 62b and 64b.

  Next, another embodiment of the present invention will be described. FIG. 5 is a longitudinal sectional view showing another embodiment, and shows an enlarged view of a speed reduction portion of an in-wheel motor drive device. Regarding the other embodiments, the same reference numerals are given to the configurations common to the above-described embodiments, and the description thereof will be omitted, and different configurations will be described below. In another embodiment, buffer members 63 and 65 made of a polymer material are provided on the rolling bearings 38 and 39 that rotatably support the speed reduction unit input shaft 25.

  The speed reducer output shaft 28 and the reinforcing member 61 that are casing side members when viewed from the speed reducer input shaft 25 rotatably support the speed reducer input shaft 25 via rolling bearings 38 and 39. The bearing 38 is a rolling bearing having an outer ring 38a, an inner ring 38b, a plurality of rolling elements 38c, and a cage (not shown). The same applies to the rolling bearing 39. A buffer member 63 made of a polymer material is interposed between the inner ring 38b and the speed reducer input shaft 25 penetrating the inner ring 38b. The buffer member 63 is an annular resin band, and is arranged at two locations with a space in the direction of the axis O. Further, a buffer member 65 made of a polymer material is interposed between the inner ring 39b and the speed reducer input shaft 25 penetrating the inner ring 39b. The buffer member 65 is an annular resin band, and is arranged at two locations with a space in the direction of the axis O. The buffer members 63 and 65 shown in FIG. 5 may be fixed by forming annular grooves on the inner peripheral surfaces of the inner rings 38b and 39b and fitting the annular buffer members 63 and 65 into the annular grooves. The material, width dimension, and thickness dimension of the buffer members 63, 65 are the same as the buffer members 63, 65 of the rolling bearings 62, 64 of the above-described embodiment, and are similarly the inner rings 38b, 39b of the rolling bearings 38, 39. The inner ring 38b, 39b is determined in consideration of the fitting state with the speed reducer input shaft 25 to be a counterpart member to which the inner rings 38b, 39b are attached and the thermal expansion difference.

  According to another embodiment, as shown in FIG. 5, the rolling bearing 39 that rotatably supports the speed reduction unit input shaft 25 included in the motor side rotation member on the speed reduction unit output shaft 28 included in the casing side member includes an inner ring It is a rolling bearing including 39b and a plurality of rolling elements 39c. Further, the rolling bearing 38 that rotatably supports the speed reducing portion input shaft 25 on the reinforcing member 61 included in the casing side member is a rolling bearing including an inner ring 38b and a plurality of rolling elements 38c. A buffer member 63 made of a polymer material is interposed between the inner ring 38b and the speed reducer input shaft 25 penetrating the inner ring 38b, and between the inner ring 39b and the speed reducer input shaft 25 penetrating the inner ring 38b. There is a buffer member 65 made of a polymer material. Thereby, even if the vibration of the deceleration part input shaft 25 is input into the rolling bearings 38 and 39, it can suppress that this vibration is transmitted to the deceleration part output shaft 28 and the reinforcement member 61. Therefore, it is possible to reduce the vibration of the casing 22 that is closer to the casing than the speed reduction unit input shaft 25.

  According to another embodiment, as shown in FIG. 5, the speed reduction unit input shaft 25 included in the motor side rotation member is coaxially arranged with the speed reduction unit output shaft 28 included in the wheel side rotation member, and the speed reduction unit output shaft 28. A circular concave portion 34 that receives the end portion of the speed reduction portion input shaft 25 is formed at the end portion. A rolling bearing 39 that rotatably supports the speed reducer input shaft 25 on the speed reducer output shaft 28 corresponding to the casing side member is defined between the inner peripheral surface of the circular recess 34 and the outer peripheral surface of the speed reducer input shaft 25. And is provided with a buffer member 65. Thereby, even if a casing side member is a member rotating like the deceleration part output shaft 28, it can suppress that a vibration is transmitted from the inside of the deceleration part B to a casing side member.

  Although not shown, as a modification of the embodiment shown in FIG. 5, the buffer members 63, 65 are not provided on the inner peripheral surfaces of the inner rings 38b, 39b, but the buffer members 63 are provided on the outer peripheral surfaces of the outer rings 38a, 39a. , 65 may be provided, and a buffer member may be interposed between the outer peripheral surface of the outer ring 38a, 39a and the inner peripheral surface of the wheel-side rotating member. Or you may provide a buffer member in both the outer peripheral surface of outer ring | wheel 38a, 39a and the inner peripheral surface of inner ring | wheel 38b, 39b.

  Next, still another embodiment of the present invention will be described. FIG. 6 is a longitudinal sectional view showing still another embodiment. Further, regarding the other embodiments, the same reference numerals are given to configurations common to the above-described embodiments, description thereof is omitted, and different configurations will be described below. In yet another embodiment, the rolling bearings 36 and 37 that rotatably support the motor rotating shaft 35 are provided with buffer members 63 and 65 made of a polymer material.

  The rolling bearing 36 includes an outer ring 36a, an inner ring 36b, a plurality of rolling elements 36c, and a retainer (not shown), and the outer peripheral surface of the outer ring 36a is attached to the inner peripheral surface of the center hole of the motor cover 22t. A buffer member 63 made of a polymer material is interposed between the outer ring 36a and the motor cover 22t included in the casing side member. The buffer member 63 is an annular resin band, and is arranged at two locations with a space in the direction of the axis O.

  The rolling bearing 37 includes an outer ring 37a, an inner ring 37b, a plurality of rolling elements 37c, and a retainer (not shown), and the outer peripheral surface of the outer ring 37a is attached to the inner peripheral surface of the center hole of the pump casing 22p. A buffer member 65 made of a polymer material is interposed between the outer ring 37a and the pump casing 22p included in the casing side member. The buffer member 65 is an annular resin band, and is arranged at two locations with a space in the direction of the axis O.

  As shown in FIG. 4 described above, the buffer members 63 and 65 may be fixed by providing annular grooves on the outer peripheral surfaces of the outer rings 36a and 37a. As described above, the width and thickness dimensions of the buffer members 63 and 65 are such that the outer rings 36a and 37a of the rolling bearings 36 and 37 and the casing 22 which is the counterpart member of the outer rings 36a and 37a are fitted and the thermal expansion difference. Is determined in consideration of

  According to still another embodiment, as shown in FIG. 6, the rolling bearings 36 and 37 that rotatably support the motor rotating shaft 35 included in the motor side rotating member on the casing 22 include outer rings 36a and 37a and a plurality of rolling bearings. It is a rolling bearing including moving bodies 36c, 37c, and buffer members 63, 65 made of a polymer material are interposed between the outer rings 36a, 37a and the casing 22. Thereby, even if the vibration of the motor rotating shaft 35 is input to the rolling bearings 36 and 37, the transmission of the vibration to the casing 22 can be suppressed. Therefore, the vibration of the casing 22 can be reduced.

The motor-side rotating member is a part of the motor unit A and outputs a motor rotation shaft 35 that outputs rotation from the motor unit A, and a speed reduction unit input shaft 25 that is a part of the speed reduction unit B and inputs rotation to the speed reduction unit B. The casing side member includes a pump casing 22p and a motor cover 22t which are part of the motor part A, and the buffer members 63 and 65 rotatably support the motor rotating shaft 35 on the pump casing 22p and the motor cover 22t. The rolling bearings 36 and 37 are provided.
Thereby, even if the vibration of the motor rotating shaft 35 is input to the rolling bearings 36 and 37, this vibration can be prevented from being transmitted to the motor cover 22t and the pump casing 22p.

  Although not shown, as a modification of the embodiment shown in FIG. 6, the buffer members 63 and 65 are not provided on the outer peripheral surfaces of the outer rings 36a and 37a, but the buffer members 63 are provided on the inner peripheral surfaces of the inner rings 36b and 37b. , 65 may be provided, and a buffer member may be interposed between the inner peripheral surface of the inner rings 36b, 37b and the outer peripheral surface of the motor rotating shaft 35. Or you may provide a buffer member in both the outer peripheral surface of the outer rings 36a and 37a, and the inner peripheral surface of the inner rings 36b and 37b.

  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. For example, you may select and combine some from the embodiment of FIG.3, FIG.5 and FIG.6 mentioned above, and the modification added by description of each embodiment.

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

21 in-wheel motor drive device, 22 casing,
22a motor casing, 22b reduction gear casing,
22p pump casing, 22t motor cover, 23 stator,
24 rotor, 25 reduction part input shaft, 25a, 25b eccentric part,
26a, 26b Curved plate, 27 Outer pin, 28 Speed reducer output shaft,
28b Large diameter flange portion, 28c Small diameter flange portion, 28d Shaft portion, 31 Inner pin, 32 Wheel hub, 33 Wheel hub bearing,
34 circular recess, 35 motor rotating shaft,
36, 37, 38, 39 Rolling bearing, 36a, 37a, 38a, 39a Outer ring,
36b, 37b, 38b, 39b Inner ring,
36c, 36c, 37c, 38c, 39c rolling elements, 45 outer pin holding part
61 reinforcing member, 61b large-diameter disk part, 61c small-diameter disk part,
61d Cylindrical part, 62, 64 Rolling bearing, 62b, 64b Inner ring
62a, 64a outer ring 62c, 64c rolling element 62d annular groove,
63, 65 Buffer member, A motor part, B deceleration part,
C Wheel hub bearing, O axis, X Spindle shaft center.

Claims (7)

A motor unit that drives the motor-side rotating member; and a speed-reducing unit that decelerates the rotation of the motor-side rotating member and outputs it to the wheel-side rotating member.
The bearing that rotatably supports the motor-side rotating member on the casing-side member and / or the bearing that rotatably supports the wheel-side rotating member on the casing-side member is a rolling bearing including an outer ring and a plurality of rolling elements. ,
An in-wheel motor drive device, wherein a buffer member made of a polymer material is interposed between the outer ring and the casing side member. A motor unit that drives the motor-side rotating member; and a speed-reducing unit that decelerates the rotation of the motor-side rotating member and outputs it to the wheel-side rotating member.
The bearing that rotatably supports the motor side rotating member on the casing side member and / or the bearing that rotatably supports the wheel side rotating member on the casing side member is a rolling bearing including an inner ring and a plurality of rolling elements. ,
An in-wheel motor drive device characterized in that a buffer member made of a polymer material is interposed between the inner ring and the motor-side rotating member and / or the wheel-side rotating member penetrating the inner ring. The motor-side rotating member includes a motor rotating shaft that is a part of the motor unit and outputs rotation from the motor unit, and a speed reducing unit input shaft that is a part of the speed reducing unit and inputs rotation to the speed reducing unit. Including
The in-wheel motor drive device according to claim 1, wherein the buffer member is provided in a bearing that rotatably supports the motor rotation shaft on the casing side member.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein the buffer member is an annular body extending along an inner peripheral surface of the inner ring or an outer peripheral surface of the outer ring.   The in-wheel motor drive device according to any one of claims 1 to 4, wherein the buffer member is an elastic body mainly composed of a fluorine-based polymer material or an acrylic-based polymer material. The motor side rotating member is coaxially arranged with the wheel side rotating member,
A circular recess that receives the end of the motor-side rotating member is formed at the end of the wheel-side rotating member,
A bearing that rotatably supports the motor-side rotating member on the casing-side member is installed in an annular space defined between an inner peripheral surface of the circular recess and an outer peripheral surface of the motor-side rotating member, and the buffer The in-wheel motor drive device in any one of Claims 1-5 with a member. The speed reduction part is an eccentric part provided eccentric to the motor side rotation member;
A revolving member that is held in the eccentric part so as to be relatively rotatable, and performs a revolving motion around the axis of the motor side rotating member as the motor side rotating member rotates,
An outer periphery engaging member that engages with the outer periphery of the revolving member to cause the revolving motion of the revolving member;
The in-wheel motor drive device according to claim 6, further comprising: a motion conversion mechanism that converts the rotation motion of the revolution member into a rotation motion centering on an axis of the motor-side rotation member and outputs the rotation motion to the wheel-side rotation member. .

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