JP2015121270A - In-wheel motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor driving device superior in NVH characteristic.SOLUTION: In an in-wheel motor driving device 21, a motor portion A rotates and drives a reduction gear input shaft 25 having eccentric portions 25a, 25b, and a decelerating portion B decelerates the rotation of the reduction gear input shaft 25 and transmits the same to a reduction gear output shaft 28. The decelerating portion B includes curved plates 26a, 26b carrying out revolving motion on a rotation axis in accompany with rotation of the reduction gear input shaft 25, and an outer pin 27 engaged with outer peripheral portions of the curved plates 26a, 26b to generate rotating motion of the curved plates 26a, 26b. The outer pin 27 is rotatably supported by a rolling bearing 61, and the rolling bearing 61 has a clearance δ of 0-40 μm after assembled.

Description

  The present invention relates to an in-wheel motor drive device.

  A conventional in-wheel motor drive device is disclosed in, for example, Japanese Patent Laid-Open No. 2008-44537 (Patent Document 1). As shown in FIG. 12, the in-wheel motor drive device 101 includes a motor unit 103 that generates a driving force, a wheel bearing unit 104 that is connected to a wheel, and a wheel bearing that decelerates rotation of the motor unit 103. The speed reduction part 105 which transmits to the part 104 and the casing 102 which hold | maintained these are provided, and the casing 102 is attached to a vehicle body via the suspension apparatus (suspension) which is not shown in figure.

  In the in-wheel motor drive device 101 having the above-described configuration, a low-torque, high-rotation type motor is adopted as the motor unit 103 from the viewpoint of making the device compact. On the other hand, the wheel bearing portion 104 requires a large torque to drive the wheel. For this reason, a cycloid reduction gear that is compact and provides a high reduction ratio is employed for the speed reduction unit 105 of the in-wheel motor drive device 101.

  The speed reducer 105 to which the cycloid speed reducer is applied includes a speed reducer input shaft 106 having eccentric portions 106a and 106b, curved plates 107a and 107b disposed on the eccentric portions 106a and 106b, and outer peripheral portions of the curved plates 107a and 107b. And a plurality of inner peripheral engagement members (outer pins) 109 that cause the curved plates 107a and 107b to rotate automatically, and a plurality of inner members that transmit the rotational motion of the curved plates 107a and 107b to the reducer output shaft 110. The pins 111 are the main components.

  The reduction gear input shaft 106 is rotatably supported by the rolling bearings 112a and 112b with respect to the casing 102 and the reduction gear output shaft 110, and the curved plates 107a and 107b are supported with respect to the reduction gear input shaft 106 by the rolling bearings 108a and 108b. And is supported rotatably. The plurality of outer pins 109 are rotatably supported with respect to the casing 102 by rolling bearings 113a and 113b arranged at both ends. A needle roller bearing 114 is incorporated in the inner pin 111 and is in rolling contact with the curved plates 107a and 107b.

JP 2008-44537 A

The in-wheel motor drive device needs to accommodate the entire device inside the wheel, and the weight and size of the in-wheel motor drive device affect the unsprung weight of the automobile and the size of the cabin space. From this point of view, the in-wheel motor drive device must be reduced in size and weight. On the other hand, in order to ensure the output required for the in-wheel motor drive device, the motor used in the motor unit is required to rotate at a high speed of, for example, 15,000 min ⁻¹ or more. In addition to the harsh usage environment and the mechanical peculiarity of the cycloid reducer, the characteristics of the in-wheel motor drive device, which is the unsprung weight, are involved in rolling bearings incorporated in the reduction part, especially NVH (Noise). , Vibration, Harshness) characteristics to be improved.

  The present invention has been proposed in view of the above-described problems, and an object thereof is to provide an in-wheel motor drive device that is excellent in NVH characteristics, and further lightweight, compact, and excellent in durability.

  In order to achieve the above object, the present invention is based on the following findings found for a rolling bearing incorporated in a speed reduction unit as a result of various studies including an internal lubrication mechanism and a cooling mechanism of an in-wheel motor drive device. ing.

  (1) Upon receiving the output of the motor unit, the speed reducer input shaft of the speed reduction unit is rotationally driven, and as a result, the curved plate and the outer pin as the outer peripheral engagement member rotate, supply lubricating oil to the speed reduction unit Even if a lubrication mechanism is provided, the temperature rise of the rolling bearing that supports the outer pin (hereinafter also referred to as “outer pin bearing”), the outer ring of the outer pin bearing and the inner ring (in the embodiments described later, the outer pin) It was found that the temperature difference was larger than expected. In such a usage state, the radial internal clearance during operation of the outer pin bearing (hereinafter also referred to as “operational clearance”) is not only reduced by fitting with other members such as the casing, but also due to the above temperature factors. To do. When the operating clearance becomes a negative clearance, heat generation occurs and there is a possibility of seizing.

  (2) In order to avoid the above problem, it is considered that the post-assembly clearance (the radial internal clearance set at the stage where the external pin bearing is incorporated in the speed reduction portion) should be increased. However, if the above-described clearance after installation is excessive, it is possible to suppress the play of the rolling bearing for supporting another rotating body (for example, a reduction gear input shaft or a curved plate) incorporated in the speed reduction unit. As a result, there is a possibility that vibration may be generated due to the swing of another rotating body, or abnormal noise / vibration may occur due to the contact between the curved plate and the outer pin and the inner pin. Since the in-wheel motor drive device is driven in a state of being housed inside the wheel, the occurrence of the above-described abnormal noise / vibration adversely affects the NVH characteristics and causes discomfort to the driver and passengers.

  (3) Furthermore, unless the outer pin bearing itself incorporated in the speed reduction part is downsized, the radial dimension of the speed reduction part cannot be accommodated within a predetermined dimension as a whole, and it is difficult to establish an in-hole motor drive device. It has been found.

  Therefore, the present invention includes a casing that holds a motor unit, a reduction unit, and a wheel bearing unit, the motor unit rotationally drives a reduction gear input shaft having an eccentric portion, and the reduction unit decelerates the rotation of the reduction gear input shaft. The in-wheel motor drive device that transmits to the reduction gear output shaft connected to the wheel bearing portion, and the reduction portion is rotatably held by the reduction gear input shaft and the eccentric portion of the reduction gear input shaft. A revolving member that performs a revolving motion centering on the rotation axis as the speed reducer input shaft rotates, and an outer peripheral engaging member that engages with the outer peripheral portion of the revolving member to cause the revolving member to rotate. A motion conversion mechanism that converts the rotational motion of the revolution member into a rotational motion centered on the rotational axis of the speed reducer input shaft and transmits the rotational motion to the speed reducer output shaft, and a speed reducer lubrication mechanism that supplies lubricating oil to the speed reducer The outer peripheral engaging member is a rolling bearing. Are lifting, the rolling bearing is characterized in that embedded after clearance is 0～40Myuemu. The “post-installation clearance” in the present invention means an internal clearance in the radial direction set in a state where the above-described rolling bearing is installed in the speed reduction portion (attached member).

  If the above configuration is adopted, the radial internal clearance of the rolling bearing that supports the outer peripheral engagement member takes into account the rise in the bearing temperature during operation, the temperature difference between the inner and outer rings, and the fit with the mounted member. There is no negative gap. Moreover, if the post-assembly clearance is set within the above numerical range, the influence of noise and vibration caused by the positive clearance can be minimized. Therefore, an in-wheel motor drive device with good NVH characteristics can be realized.

  The bearing ring constituting the rolling bearing is preferably made of bearing steel or carburized steel, is subjected to carbonitriding, and the amount of retained austenite in the surface layer portion is preferably 20 to 35%. In this way, it is possible to improve the rolling fatigue life and to suppress the generation and development of cracks due to retained austenite, thereby improving the durability (longer life) of the in-wheel motor drive device. be able to. Further, in order to ensure the same life, it is possible to reduce the thickness of the bearing ring as compared to the case where the bearing ring not having the above configuration is employed. Therefore, the in-wheel motor drive device can be reduced in size and weight through, for example, downsizing the rolling bearing in the radial direction.

  Further, for the same reason as described above, the rolling elements constituting the rolling bearing are preferably made of bearing steel, subjected to carbonitriding, and the amount of retained austenite in the surface layer portion is preferably 20 to 35%.

  If the above-mentioned rolling bearing is a needle roller bearing, the load capacity can be increased while reducing the size of the rolling bearing itself as compared with a case where the rolling bearing is constituted by, for example, a ball bearing. Therefore, it is suitable for realizing an in-wheel motor drive device that is small and lightweight and has excellent durability.

  The needle roller bearing is disposed between an outer ring having an outer raceway surface on the inner diameter surface, an inner raceway surface formed directly on the outer diameter surface of the outer peripheral engagement member, and the outer raceway surface and the inner raceway surface. It can be composed of a plurality of needle rollers. In this way, if a needle roller bearing of the type in which the inner ring is omitted is adopted, the rolling bearing supporting the outer peripheral engagement member can be further reduced in size and weight, so that the in-wheel motor drive device is further reduced in size and weight. Can be

  As described above, according to the present invention, it is possible to realize an in-wheel motor drive device that is excellent in NVH characteristics, and that is compact, lightweight, and excellent in durability.

It is a figure which shows the in-wheel motor drive device which concerns on one Embodiment of this invention. It is a cross-sectional view in OO of FIG. It is an enlarged view of the deceleration part of FIG. It is a schematic longitudinal cross-sectional view of the rolling bearing which supports an outer periphery engaging member. It is explanatory drawing which shows the load which acts on the curve board of FIG. It is a cross-sectional view in PP of FIG. It is a cross-sectional view in QQ of FIG. It is a cross-sectional view in RR of FIG. It is a cross-sectional view of the rotary pump of FIG. It is a schematic plan view of an electric vehicle. It is the schematic sectional drawing which looked at the electric vehicle of Drawing 10 from back. It is a figure which shows the conventional in-wheel motor drive device.

  An in-wheel motor drive device according to an embodiment of the present invention will be described with reference to the drawings.

  First, for the sake of convenience, an outline of an electric vehicle 11 equipped with an in-wheel motor drive device will be described based on FIGS. 10 and 11. As shown in FIG. 10, the electric vehicle 11 includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a drive wheel, and an in-wheel motor drive device 21 that drives each of the left and right rear wheels 14. Is provided. As shown in FIG. 11, the rear wheel 14 is accommodated in the wheel housing 12a of the chassis 12, and is fixed to the lower part of the chassis 12 via a suspension device (suspension) 12b.

  The suspension device 12b supports the rear wheel 14 by a suspension arm extending left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear wheel 14 from the road surface by a strut including a coil spring and a shock absorber. Furthermore, a stabilizer that suppresses the inclination of the vehicle body during turning or the like is provided at a connecting portion of the left and right suspension arms. The suspension device 12b is an independent suspension type that can move the left and right wheels up and down independently in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the driving wheel (rear wheel 14) to the road surface. Is desirable.

  In the electric vehicle 11, since the in-wheel motor drive device 21 that drives the left and right rear wheels 14 is provided inside the left and right wheel housings 12 a, a motor, a drive shaft, a differential gear mechanism, and the like are provided on the chassis 12. There is no need. For this reason, it is possible to secure a wide cabin space and to control the rotation of the left and right drive wheels.

  In order to improve the running stability and NVH characteristics of the electric vehicle 11, it is necessary to suppress the unsprung weight. Moreover, in order to expand the cabin space of the electric vehicle 11, it is necessary to reduce the size of the in-wheel motor drive device 21. Therefore, as shown in FIG. 1, an in-wheel motor drive device 21 according to an embodiment of the present invention is employed.

  The in-wheel motor drive device 21 which concerns on one Embodiment of this invention is demonstrated based on FIGS. As shown in FIG. 1, 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 an output from the deceleration unit B as driving wheels. 14 and a wheel bearing portion C that is transmitted to 14, and these are held in the casing 22. The motor part A and the speed reduction part B are mounted in a wheel housing 12a (see FIG. 11) of the electric vehicle 11 while being housed in the casing 22.

  The motor part A is connected and fixed to the stator 23a fixed to the casing 22, the rotor 23b opposed to the inner side of the stator 23a via a radial gap, and the inner side of the rotor 23b, and rotates integrally with the rotor 23b. It is a radial gap motor provided with the motor rotating shaft 24a to perform.

  The motor rotation shaft 24a having a hollow structure is fitted and fixed to the inner diameter surface of the rotor 23b to rotate integrally with the rotor 23b, and is on one side in the axial direction (the right side in FIG. 1 and hereinafter also referred to as “vehicle width direction inner side”). In addition, end portions on the other side in the axial direction (the left side in FIG. 1 and also referred to as “the vehicle width direction outer side”) are rotatably supported by rolling bearings 36a and 36b, respectively.

  The reduction gear input shaft 25 has a substantially central portion in the axial direction and an end portion on the outer side in the vehicle width direction, which are rotatably supported by the reduction gear output shaft 28 by rolling bearings 37a and 37b, respectively. The speed reducer input shaft 25 has eccentric portions 25 a and 25 b in the range of the speed reduction portion B. The two eccentric portions 25a and 25b are provided so as to have a phase difference of 180 ° in order to cancel the centrifugal force caused by the eccentric motion.

  The motor rotating shaft 24a and the speed reducer input shaft 25 are connected by serration fitting in order to transmit the driving force of the motor part A to the speed reducing part B. The serration fitting portion is configured to suppress the influence on the motor rotation shaft 24a even if the speed reducer input shaft 25 is inclined to some extent.

  The deceleration portion B is held at a fixed position on the casing 22 and curved plates 26a and 26b as revolving members that are rotatably held by the eccentric portions 25a and 25b, and engages with the outer peripheral portions of the curved plates 26a and 26b. A plurality of outer pins 27 as outer peripheral engagement members, a motion conversion mechanism for transmitting the rotational motions of the curved plates 26a and 26b to the reducer output shaft 28, and a counter disposed adjacent to the outer side in the axial direction of the eccentric portions 25a and 25b. Weights 29 and 29 are provided. In addition, the speed reduction part B is provided with a speed reduction part lubrication mechanism that supplies lubricating oil to various parts of the speed reduction part B. Details of the speed reduction part lubrication mechanism will be described later.

  The reduction gear output shaft 28 has a flange portion 28a and a shaft portion 28b. On the end face of the flange portion 28a, holes for fixing the inner pins 31 at equal intervals are formed on the circumference centered on the rotational axis of the reduction gear output shaft 28. The shaft portion 28b is fitted and connected to the hub wheel 32, and transmits the output of the speed reduction portion B to the rear wheel 14 (see FIG. 10) as a drive wheel.

  As shown in FIG. 2, the curved plate 26 a has a plurality of waveforms composed of a trochoidal curve such as an epitrochoid on the outer peripheral portion thereof. The curved plate 26a has axial through-holes 30a and 30b that open at both end faces thereof. A plurality of through holes 30a are provided at equal intervals on the circumference centering on the rotation axis of the curved plate 26a, and one inner pin 31 is inserted through each through hole 30a. The through hole 30b is provided at the center of the curved plate 26a and is fitted to the eccentric portion 25a.

  The curved plate 26a is rotatably supported by the rolling bearing 41 with respect to the eccentric portion 25a. As shown in FIG. 2 and FIG. 3, the rolling bearing 41 has an inner raceway surface 42a on the outer diameter surface, an inner ring 42 fitted to the outer diameter surface of the eccentric portion 25a, and a through hole 30b of the curved plate 26a. A cylindrical roller bearing comprising an outer raceway surface 43 formed on the inner diameter surface, a plurality of cylindrical rollers 44 disposed between the inner raceway surface 42 a and the outer raceway surface 43, and a cage 45 that holds the cylindrical rollers 44. is there. The inner ring 42 has flanges 42b that protrude radially outward from both axial ends of the inner raceway surface 42a. In the rolling bearing 41, the inner raceway 42a is formed on the inner ring 42 provided separately from the eccentric portion 25a. However, the inner raceway 42 is formed directly on the outer diameter surface of the eccentric portion 25a. It may be omitted. Although detailed illustration and description are omitted, the curved plate 26b is rotatably supported with respect to the eccentric portion 25b by a rolling bearing having the same structure as the rolling bearing 41 that supports the curved plate 26a.

  As shown in FIGS. 2 and 3, the outer pins 27 as outer peripheral engagement members are provided at equal intervals on the circumference centering on the rotational axis of the speed reducer input shaft 25. When the curved plates 26a and 26b revolve, the curved waveform formed on the outer periphery of the curved plates 26a and 26b and the outer pin 27 are engaged in the circumferential direction to cause the curved plates 26a and 26b to rotate. Each outer pin 27 is freely rotatable in the radial direction with respect to the casing 22 (see FIG. 1) by rolling bearings 61 and 61 arranged at the ends of one axial side and the other side (inner side and outer side in the vehicle width direction). It is supported by. With this configuration, the contact resistance between the outer pin 27 and the curved plates 26a and 26b can be reduced. In the present embodiment, the outer pin 27 is disposed on the rolling bearing 61 and the outer periphery thereof, and is rotatably supported in the radial direction with respect to the casing 22 via the housing 60 holding the rolling bearing 61 on the inner periphery. However, the housing 60 may be omitted, and the rolling bearing 61 may be directly fixed to the inner periphery of the casing 22. In any case, the outer pin 27 is rotatably supported with respect to the casing 22.

  As schematically shown in FIG. 4, the rolling bearing 61 of the present embodiment has an outer raceway surface 63 on the inner periphery, an outer ring 62 fixed to the inner periphery of the housing 60, and an outer diameter surface of the outer pin 27. Is a needle roller bearing comprising an inner raceway surface 64 formed on the inner raceway and a plurality of needle rollers 65 disposed between the raceway surfaces 63, 64. It is arranged in a full roller state. Thus, by adopting the needle roller bearing as the rolling bearing 61, it is possible to secure a large load capacity while reducing the size of the rolling bearing 61 that supports the outer pin 27 in the radial direction. In particular, since the rolling bearing 61 of the present embodiment is a needle roller bearing that does not have an inner ring or a cage, the rolling bearing 61 can be further reduced in size and weight. If there is no particular problem in terms of load capacity, it is possible to use a rolling bearing 61 provided with a cage that holds the needle rollers 65 at an appropriate interval. In the present invention, the above-mentioned rolling bearing 61 has a characteristic configuration, and details thereof will be described later.

  The counterweight 29 is substantially fan-shaped and has a through hole that engages with the speed reducer input shaft 25, and in order to cancel out the unbalanced inertia couple caused by the rotation of the curved plates 26a and 26b, the eccentric portions 25a and 25b. In the positions adjacent to each other in the axial direction, the eccentric portions 25a and 25b are arranged with a phase difference of 180 °.

As shown in FIG. 3, when the center point in the rotational axis direction between the two curved plates 26 a and 26 b is defined as G, between the curved plate 26 a arranged on the right side of the central point G and the counterweight 29. Is established as follows: L ₁ × m ₁ × ε ₁ = L ₂ × m ₂ × ε ₂ (where L ₁ is the distance between the center point G and the center of the curved plate 26a, m ₁ : Sum of masses of curved plate 26 a, rolling bearing 41 and eccentric portion 25 a, ε ₁ : Eccentric amount of the center of gravity of curved plate 26 a from the rotation axis, L ₂ : Distance between center point G and counterweight 29, m _{2 is} the mass of the counterweight 29, and ε ₂ is the amount of eccentricity of the center of gravity of the counterweight 29 from the rotational axis). The above-described relationship of L ₁ × m ₁ × ε ₁ = L ₂ × m ₂ × ε ₂ allows for an unavoidable error. In addition, the same relationship as described above is established between the curved plate 26b disposed on the left side of the center point G in FIG.

  The motion conversion mechanism includes a plurality of inner pins 31 held by the reduction gear output shaft 28 and through holes 30a provided in the curved plates 26a and 26b. The inner pins 31 are provided at equal intervals on a circumference centered on the rotational axis of the speed reducer output shaft 28, and an end portion on the outer side in the vehicle width direction is fixed to the speed reducer output shaft 28. Since the speed reducer output shaft 28 is arranged coaxially with the speed reducer input shaft 25, the rotational motion of the curved plates 26a and 26b is converted into rotational motion about the rotational axis of the speed reducer input shaft 25. This is transmitted to the reduction gear output shaft 28. Further, in order to reduce the frictional resistance between the inner pin 31 and the curved plates 26a and 26b, a needle roller bearing 31a is provided at a position where the inner surface of the through hole 30a of the curved plates 26a and 26b comes into contact.

  A stabilizer 31 b is provided at the axial end of the inner pin 31. The stabilizer 31b includes an annular ring portion 31c and a cylindrical portion 31d extending in the axial direction from the inner diameter surface of the annular portion 31c. The ends of the inner pins 31 on the inner side in the vehicle width direction are fixed to the annular portion 31c. Thereby, since the load applied to a part of the inner pins 31 from the curved plates 26a and 26b is supported by all the inner pins 31 via the stabilizer 31b, the stress acting on the inner pins 31 is reduced and the durability is improved. Can be improved.

  As shown in FIG. 2, the through hole 30 a is provided at a position corresponding to each of the plurality of inner pins 31, and the inner diameter of the through hole 30 a is the outer diameter of the inner pin 31 (“including the needle roller bearing 31 a. It is set to be larger than the maximum outer diameter.

  As shown in FIG. 1, the wheel bearing portion C includes a hub wheel 32 connected to the reduction gear output shaft 28 and a wheel bearing 33 that rotatably supports the hub wheel 32 with respect to the casing 22. The hub wheel 32 has a cylindrical hollow portion 32a and a flange portion 32b. The rear wheel 14 (see FIGS. 10 and 11) is connected and fixed to the flange portion 32b by a bolt 32c. A spline is formed on the outer diameter surface of the shaft portion 28 b of the reduction gear output shaft 28, and the spline is fitted into a spline hole formed in the inner diameter surface of the hollow portion 32 a of the hub wheel 32, thereby reducing the speed reducer. The output shaft 28 and the hub wheel 32 are connected so that torque can be transmitted.

  The wheel bearing 33 is fitted to an inner bearing member having an inner raceway surface 33 f formed on the outer diameter surface of the hub wheel 32 and an inner ring 33 a fitted to a small diameter step portion of the outer diameter surface, and the inner diameter surface of the casing 22. A fixed outer ring 33b, a plurality of rolling elements (balls) 33c disposed between the inner bearing member and the outer ring 33b, a retainer 33d that holds a gap between balls 33c adjacent in the circumferential direction, and a wheel bearing 33 It is a double row angular contact ball bearing provided with the sealing member 33e which seals both axial direction both ends.

  Next, the speed reducer lubrication mechanism will be described. The speed reduction part lubrication mechanism supplies lubricating oil to various parts of the speed reduction part B, and as shown in FIGS. 1 and 3, a lubricating oil path 25c and a lubricating oil supply port 25d provided in the speed reducer input shaft 25 are provided. , 25e, 25f, a lubricating oil passage 31e provided in the stabilizer 31b, a lubricating oil passage 31f provided in the inner pin 31, a lubricating oil outlet 22b provided in the casing 22, a lubricating oil reservoir 22d, and a lubricating oil passage 22e. The lubricating oil passage 45 and the rotary pump 51 are the main components. The white arrow shown in FIG. 1 indicates the direction in which the lubricating oil flows.

  The lubricating oil passage 25c extends along the axial direction inside the reduction gear input shaft 25. The lubricating oil supply ports 25d and 25e extend from the lubricating oil passage 25c toward the outer diameter surface of the speed reducer input shaft 25, and the lubricating oil supply port 25f extends from the shaft end of the speed reducer input shaft 25 in the direction of the rotational axis. It extends toward the shaft end face.

  At least one location of the casing 22 at the position of the speed reduction portion B is provided with a lubricating oil discharge port 22b for discharging the lubricating oil inside the speed reduction portion B. A circulating oil passage 45 that connects the lubricating oil discharge port 22 b and the lubricating oil passage 25 c is provided inside the casing 22. The lubricating oil discharged from the lubricating oil discharge port 22 b returns to the lubricating oil path 25 c via the circulating oil path 45.

  As shown in FIGS. 1 and 6 to 8, the circulating oil passage 45 provided in the casing 22 includes an axial oil passage 45 a extending in the axial direction inside the casing 22 and an inner side in the vehicle width direction of the axial oil passage 45 a. And a radial oil passage 45c extending in the radial direction and connected to an outer end portion in the vehicle width direction of the axial oil passage 45a and extending in the radial direction. The radial oil passage 45b supplies the lubricating oil pumped from the rotary pump 51 to the axial oil passage 45a, and supplies the lubricating oil from the axial oil passage 45a to the lubricating oil passage 25c via the radial oil passage 45c.

  The rotary pump 51 is provided between the lubricating oil passage 22e connected to the lubricating oil reservoir 22d and the circulating oil passage 45, and forcibly circulates the lubricating oil. As shown in FIG. 9, the rotary pump 51 includes an inner rotor 52 that rotates using the rotation of the speed reducer output shaft 28 (see FIG. 1), and an outer rotor 53 that rotates following the rotation of the inner rotor 52. The cycloid pump includes a pump chamber 54, a suction port 55 that communicates with the lubricating oil passage 22e, and a discharge port 56 that communicates with the radial oil passage 45b of the circulation oil passage 45.

  Inner rotor 52 has a tooth profile formed of a cycloid curve on the outer diameter surface. Specifically, the shape of the tooth tip portion 52a is an epicycloid curve, and the shape of the tooth gap portion 52b is a hypocycloid curve. The inner rotor 52 is fitted to the outer diameter surface of the cylindrical portion 31d (see FIGS. 1 and 3) of the stabilizer 31b and rotates integrally with the inner pin 31 and the speed reducer output shaft 28.

  The outer rotor 53 has a tooth profile constituted by a cycloid curve on the inner diameter surface. Specifically, the shape of the tooth tip portion 53a is a hypocycloid curve, and the shape of the tooth gap portion 53b is an epicycloid curve. The outer rotor 53 is rotatably supported by the casing 22.

The inner rotor 52 is rotated about the rotation center c _1. On the other hand, the outer rotor 53 rotates around a rotation center c ₂ different from the rotation center c ₁ of the inner rotor 52. When the number of teeth of the inner rotor 52 is n, the number of teeth of the outer rotor 53 is (n + 1). In this embodiment, n = 5.

A plurality of pump chambers 54 are provided in the space between the inner rotor 52 and the outer rotor 53. When the inner rotor 52 rotates using the rotation of the reduction gear output shaft 28, the outer rotor 53 rotates in a driven manner. At this time, since the inner rotor 52 and the outer rotor 53 rotate about different rotation centers c ₁ and c ₂ , the volume of the pump chamber 54 changes continuously. As a result, the lubricating oil flowing in from the suction port 55 is pumped from the discharge port 56 to the radial oil passage 45b.

  If the inner rotor 52 is tilted during the rotation of the rotary pump 51 configured as described above, the volume of the pump chamber 54 changes and the lubricating oil cannot be properly pumped, or the inner rotor 52 and the outer rotor 53 are There is a risk of contact and damage. Therefore, as shown in FIG. 1, the inner rotor 52 is provided with a stepped portion 52 c. The stepped portion 52 c has an outer diameter surface (guide surface) that abuts against the inner diameter surface of the casing 22, and prevents the inner rotor 52 from being inclined by a radial load from the wheel 14.

  Between the lubricating oil discharge port 22b and the rotary pump 51, there is provided a lubricating oil reservoir 22d for temporarily storing the lubricating oil. Thereby, at the time of high speed rotation, the lubricating oil that cannot be discharged by the rotary pump 51 can be temporarily stored in the lubricating oil storage section 22d. As a result, an increase in torque loss of the deceleration unit B can be prevented. On the other hand, at the time of low speed rotation, the lubricating oil stored in the lubricating oil reservoir 22d can be returned to the lubricating oil passage 25c even if the amount of lubricating oil reaching the lubricating oil discharge port 22b decreases. As a result, the lubricating oil can be stably supplied to the deceleration unit B.

  Lubricating oil inside the deceleration part B moves to the outside also by gravity in addition to centrifugal force. Therefore, it is desirable that the in-wheel motor drive device 21 is attached to the electric vehicle 11 (see FIGS. 10 and 11) so that the lubricating oil reservoir 22d is positioned below the in-wheel motor drive device 21.

  The flow of the lubricating oil in the deceleration portion B having the above configuration will be described. First, the lubricating oil flowing through the lubricating oil passage 25c flows out from the lubricating oil supply ports 25d, 25e, and 25f to the speed reducing unit B due to the centrifugal force and pressure accompanying the rotation of the speed reducer input shaft 25. Thereafter, the lubricating oil flows to the rolling bearings in the deceleration portion B as follows.

  The lubricating oil flowing out from the lubricating oil supply ports 25e and 25f is supplied to the rolling bearings 37a and 37b that support the reduction gear input shaft 24b by the action of centrifugal force. Further, the lubricating oil flowing out from the lubricating oil supply port 25e is guided to the lubricating oil passage 31e in the stabilizer 31b, reaches the lubricating oil passage 31f in the inner pin 31, and supports the inner pin 31 from the lubricating oil passage 31f. It is supplied to a rolling bearing (needle roller bearing) 31a. Further, due to the centrifugal force, the contact portion between the curved plates 26a, 26b and the inner pin 31, the contact portion between the curved plates 26a, 26b and the outer pin 27, the rolling bearing 61 that supports the outer pin 27, the output shaft of the speed reducer It moves to the outer side in the radial direction while lubricating the rolling bearing 46 and the like that support the 28 (stabilizer 31b).

  On the other hand, the lubricating oil flowing out from the lubricating oil supply port 25d is supplied into the bearing from a supply hole 42c (see FIG. 3) provided in the inner ring 42 of the rolling bearing 41 that supports the curved plates 26a and 26b. Thereby, the outer surface of the cylindrical roller 44, the inner raceway surface 42a, and the outer raceway surface 43 are lubricated. Further, like the lubricating oil flowing out from the lubricating oil supply ports 25e and 25f, the contact between the curved plates 26a and 26b and the inner pin 31 and the contact between the curved plates 26a and 26b and the outer pin 27 are caused by centrifugal force. Moves radially outward while lubricating the contact part.

  The rolling bearings in the speed reduction unit B are lubricated by the flow of the lubricating oil as described above. The lubricating oil that has reached the inner wall surface of the casing 22 is discharged from the lubricating oil discharge port 22b and stored in the lubricating oil storage portion 22d. The lubricating oil stored in the lubricating oil reservoir 22d is supplied from the suction port 55 to the rotary pump 51 through the lubricating oil passage 22e, and is pumped from the discharge port 56 to the circulating oil passage 45. As a result, the lubricating oil returns to the lubricating oil passage 25c via the radial oil passage 45b, the axial oil passage 45a, and the radial oil passage 45c of the circulation oil passage 45.

  The amount of lubricating oil discharged from the lubricating oil discharge port 22 b increases in proportion to the rotational speed of the speed reducer input shaft 25. On the other hand, since the inner rotor 52 rotates integrally with the speed reducer output shaft 28, the discharge amount of the rotary pump 51 increases in proportion to the rotational speed of the speed reducer output shaft 28. Then, the amount of lubricating oil supplied from the lubricating oil discharge port 22 b to the speed reduction unit B increases in proportion to the discharged amount of the rotary pump 51. That is, since both the supply amount and the discharge amount of the lubricating oil to the speed reduction unit B change depending on the rotational speed of the in-wheel motor drive device 21, the lubricating oil can be circulated smoothly and constantly.

  Part of the lubricating oil flowing through the circulating oil passage 45 lubricates the rolling bearing 36a that supports the inner end in the vehicle width direction of the motor rotation shaft 24a from between the casing 22 and the motor rotation shaft 24a. The rolling bearing 36b that supports the outer end of the motor rotating shaft 24a in the vehicle width direction is lubricated by lubricating oil from between the stepped portion 52c of the rotary pump 51 and the casing 22.

  Thus, by supplying lubricating oil from the speed reducer input shaft 25 to the speed reducing portion B, a shortage of lubricating oil around the speed reducer input shaft 25 can be solved. Further, by forcibly discharging the lubricating oil by the rotary pump 51, it is possible to suppress the stirring resistance and reduce the torque loss of the speed reduction unit B. Furthermore, by arranging the rotary pump 51 in the casing 22, it is possible to prevent the in-wheel motor drive device 21 from being enlarged as a whole.

  Although the speed reduction part B includes the speed reduction part lubrication mechanism described above, each rolling bearing in the speed reduction part B is exposed to a very severe usage environment when the in-wheel motor drive device 21 (motor part A) is driven. . The details will be described based on FIG. 5 schematically showing the state of the load acting on the curved plates 26a and 26b when the motor part A is driven.

The axis O ₂ of the eccentric portion 25 a provided on the speed reducer input shaft 25 is eccentric from the axis O of the speed reducer input shaft 25 by the amount of eccentricity e. The outer periphery of the eccentric portion 25a is attached is curved plates 26a, the eccentric part 25a is so rotatably supports the curve plate 26a, the axial center O ₂ is also the axis of the curved plate 26a. The outer peripheral portion of the curved plate 26a is formed by a corrugated curve, and has corrugated concave portions 33 that are depressed in the radial direction at equal intervals in the circumferential direction. Around the curved plate 26a, a plurality of outer pins 27 that engage with the recesses 33 are arranged in the circumferential direction with the axis O as the center.

  In FIG. 5, when the eccentric part 25a rotates counterclockwise on the paper surface integrally with the speed reducer input shaft 25, the eccentric part 25a performs a revolving motion around the axis O, so that the concave part 33 of the curved plate 26a The outer pins 27 are sequentially brought into contact with the circumferential direction. As a result, the curved plate 26a receives a load Fi as indicated by an arrow in the drawing from the plurality of outer pins 27, and rotates clockwise.

Further, the curved plates 26a through hole 30a has a plurality circumferentially disposed about the axis O _2. Each through-hole 30a is inserted with an inner pin 31 that is coupled to the reduction gear output shaft 28 that is disposed coaxially with the axis O. Since the inner diameter of the through hole 30a is larger than the outer diameter of the inner pin 31, the inner pin 31 does not become an obstacle to the revolution movement of the curved plate 26a. 28 is rotated. At this time, the speed reducer output shaft 28 has a higher torque and a lower rotational speed than the speed reducer input shaft 25, and the curved plate 26a receives a load Fj as indicated by arrows in the figure from the plurality of inner pins 31. A resultant force Fs of the plurality of loads Fi and Fj is applied to the reduction gear input shaft 25.

The direction of the resultant force Fs changes due to the influence of centrifugal force in addition to geometrical conditions such as the waveform shape of the curved plate 26a and the number of the concave portions 33. Specifically, the angle α between the reference line X perpendicular to the straight line Y connecting the rotation axis O ₂ and the axis O and passing through the rotation axis O ₂ and the resultant force Fs is approximately 30 ° to 60 °. It fluctuates with. The load directions and magnitudes of the plurality of loads Fi and Fj change during one rotation (360 °) of the speed reducer input shaft 25. As a result, the resultant force Fs acting on the speed reducer input shaft 25 is also a load. The direction and size of fluctuate. Then, when the speed reducer input shaft 25 rotates once, the corrugated concave portion 33 of the curved plate 26a is decelerated and rotated clockwise by one pitch, resulting in the state of FIG. 5, and this is repeated.

  For this reason, when the motor part A is driven, the rolling bearing (needle roller bearing) 61 that supports the outer pin 27 is loaded with a radial load and a moment load that vary in the direction and magnitude of the load in addition to the high-speed rotation. Will be. As a result, it was found that the temperature difference between the inner and outer rings (here, the outer pin 27 and the outer ring 62) of the rolling bearing 61 becomes larger than expected in addition to the temperature of the rolling bearing 61 significantly increasing. In order to cope with this, even when the post-installation clearance δ of the rolling bearing 61 is set in consideration of the fit to the outer pin housing 60 (casing 22), if the amount of the post-assembly clearance δ is as small as possible, It was found that the gap became negative, and heat was generated, leading to early peeling and seizure.

  In order to avoid the occurrence of such a problem, the value of the post-installation clearance δ of the rolling bearing 61 may be increased. However, if the post-assembly clearance δ is excessive, it is disposed in the speed reduction portion B. Vibrations due to the swinging of various rotating bodies generated, or abnormal noises or vibrations due to the contact portions of the curved plates 26a, 26b with the outer pins 27 and the inner pins 31 occur. It has been found that the in-wheel motor drive device 21 equipped with the cycloid reduction gear is sensitive to these abnormal sounds and vibrations. In addition, since the special condition of the in-wheel motor drive device 21 that is the unsprung weight is superimposed, it is difficult to attenuate the noise and vibration described above, which adversely affects the NVH characteristics and is uncomfortable for the driver and the passenger. It was also found to give.

なお、表１中の評価基準は次のとおりである。
〔騒音・振動〕
後部座席に乗車した人を模擬した状態で、騒音計により騒音レベルを測定する。
○：ほとんどの人・条件で騒音による不快感がない状態
△：敏感な人だけ、又は特定の条件下のみで騒音を不快に感じる状態
×：ほとんどの人が騒音を不快に感じる状態
〔軸受寿命〕
○：基準車両寿命１０年１０万ｋｍを達成可能
△：厳しい条件で使用される車両では、上記車両寿命を満足しない場合がある
×：上記基準車両寿命を達成不可能 In this way, the rolling bearing 61 that supports the outer pin 27 of the in-wheel motor drive device 21 of the present embodiment can be processed with a built-in clearance δ in view of being used in a special environment involving various factors. In order to pursue an appropriate range, experiments were evaluated. The results are shown in Table 1 below.

The evaluation criteria in Table 1 are as follows.
[Noise and vibration]
Measure the noise level with a sound level meter while simulating a person in the back seat.
○: No discomfort due to noise in most people / conditions △: Only sensitive people or only under certain conditions feel noise unpleasant ×: Most people feel uncomfortable noise [Bearing life ]
○: A standard vehicle life of 100,000 km can be achieved. Δ: A vehicle used under severe conditions may not satisfy the vehicle life. ×: The standard vehicle life cannot be achieved.

  From the experimental results shown in Table 1, the post-assembly clearance δ of the rolling bearing 61 that supports the outer pin 27 in the radial direction in the deceleration portion B of the in-hole motor drive device 21 is set to 0 to 40 μm, whereby the housing 60 It can prevent heat generation and seizure even under conditions such as fitting with (casing 22), temperature rise, and temperature difference between inner and outer rings, and it can be processed within a range where NVH characteristics can be reduced due to noise and vibration. It was found that it can be minimized. Thereby, in spite of special conditions such as an in-wheel motor drive device and a cycloid reducer that are unsprung weights, it is possible to realize an in-wheel motor drive device that suppresses abnormal noise and vibration and has excellent NVH characteristics. .

  Here, the post-assembly clearance δ will be described in detail. As shown in FIG. 4, the post-assembly clearance δ means that either the outer ring 62 or the outer pin 27 is fixed in a state where the rolling bearing 61 is installed in the speed reduction part B (in this case, the housing 60), and the other is used. This means the amount of movement when moving in the radial direction. In other words, a clearance formed between the inner raceway surface 64 of the outer pin 27 and the needle roller 65 in a state where the needle roller 65 is in contact with the outer raceway surface 63 of the outer ring 62, or the outer pin 27. It means a clearance formed between the outer raceway surface 63 of the outer ring 62 and the needle rollers 65 in a state where the needle rollers 65 are in contact with the inner raceway surface 64. FIG. 4 schematically shows the latter state.

  Further, in terms of the material and heat treatment of the constituent members of the rolling bearing 61, the bearing ring (the outer ring 62 and the outer pin 27) is made of bearing steel or carburized steel, and the needle rollers 65 are made of bearing steel. The bearing rings and needle rollers 65 were subjected to carbonitriding treatment, and nitrogen was diffused in these surface layer portions to stably hold 20 to 35% of retained austenite. Here, as bearing steel, SUJ3 and SUJ5 which are high carbon chromium bearing steel prescribed | regulated to JISB4805 can be used, for example. Moreover, as carburized steel, SCM415, SCM420, SCr420 etc. can be used, for example. In this embodiment, all of the outer pin 27, the outer ring 62 and the needle roller 65 are made of SUJ3, and nitrogen is diffused in these surface layers by carbonitriding to stably hold 20 to 35% residual austenite. It was.

  Due to the above materials and heat treatment, the retained austenite reduces crack sensitivity, so that the corrected rated life (ISO 281) can be improved, and the rolling bearing 61 has a long life. In other words, in order to ensure the same life, the bearing ring (outer ring 62) is made thinner and the rolling bearing 61 has a diameter compared to the case of using a rolling bearing (race ring or rolling element) that does not have the above configuration. It can be downsized in the direction. In this way, through the durability improvement and downsizing of the rolling bearing 61, the in-wheel motor drive device 21 that is rich in durability and that is small and light can be realized.

  In the present embodiment, as described above, all of the outer ring 62, the outer pin 27, and the needle roller 65 constituting the rolling bearing 61 are made of SUJ3, and the amount of retained austenite in the surface layer portion is 20 to 35%. Although an example in which heat treatment is performed has been shown, other configurations can be adopted. For example, at least one of the bearing rings (in this case, the outer ring 62 and the outer pin 27) and the needle rollers 65 constituting the rolling bearing 61 is made of bearing steel, and the amount of retained austenite in the surface layer portion is 20 to 20 by carbonitriding. A configuration of 35% may be employed.

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

  In the motor part A, for example, the rotor 23b made of a permanent magnet or a magnetic material rotates by receiving an electromagnetic force generated by supplying an alternating current to the coil of the stator 23a. Accordingly, when the reduction gear input shaft 25 connected to the motor rotation shaft 24 a rotates, the curved plates 26 a and 26 b revolve around the rotation axis of the reduction gear input shaft 25. At this time, the outer pin 27 engages with a curved waveform provided on the outer periphery of the curved plates 26a and 26b, and rotates the curved plates 26a and 26b in the direction opposite to the rotation of the speed reducer input shaft 25. .

  The inner pin 31 inserted through the through hole 30a comes into contact with the inner wall surface of the through hole 30a as the curved plates 26a and 26b rotate. As a result, the revolving motion of the curved plates 26 a and 26 b is not transmitted to the inner pin 31, and only the rotational motion of the curved plates 26 a and 26 b is transmitted to the wheel bearing portion C via the reduction gear output shaft 28. At this time, since the rotation of the speed reducer input shaft 25 is decelerated by the speed reducing portion B and transmitted to the speed reducer output shaft 28, even when the low torque, high speed motor portion A is employed, the drive wheel (rear wheel) ) 14 can transmit the necessary torque.

The speed reduction ratio of the speed reduction part B having the above configuration is (Z _A −Z _B ) / Z _B , where Z _{A is} the number of outer pins 27 and Z _B is the number of waveforms provided on the outer peripheral parts of the curved plates 26a and 26b. Is calculated by In the embodiment shown in FIG. 2, since Z _A = 12 and Z _B = 11, a very large reduction ratio of 1/11 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. Further, by providing rolling bearings (needle roller bearings) 61 and 31a that rotatably support the outer pin 27 and the inner pin 31, friction between the outer pin 27 and the inner pin 31 and the curved plates 26a and 26b is provided. Since the resistance is reduced, the transmission efficiency of the deceleration unit B is improved.

  The in-wheel motor drive device 21 according to the present embodiment is reduced in weight as described above. Therefore, if the in-wheel motor apparatus 21 of this embodiment is mounted in the electric vehicle 11, the unsprung weight can be suppressed. As a result, the electric vehicle 11 having excellent running stability and NVH characteristics can be obtained.

  As described above, the in-wheel motor driving device 21 according to the embodiment of the present invention has been described. However, the in-wheel motor driving device 21 can be variously modified without departing from the gist of the present invention. is there.

  For example, the embodiment described above shows an example in which the lubricating oil supply port 25d is provided in the eccentric portions 25a and 25b, and the lubricating oil supply ports 25e and 25f are provided in the middle position and the shaft end of the speed reducer input shaft 25. However, the present invention is not limited to this, and the speed reducer input shaft 25 can be provided at an arbitrary position. However, from the viewpoint of stably supplying lubricating oil to the rolling bearings 41, 37a, and 37b, the lubricating oil supply port 25d is provided to the eccentric portions 25a and 25b, and the lubricating oil supply ports 25e and 25f are provided to the speed reducer input shaft 25. It is desirable to be provided in the middle position and at the shaft end.

  In the above, the example in which the rotary pump 51 is driven by using the rotation of the speed reducer output shaft 28 has been described. However, the rotary pump 51 can also be driven by using the rotation of the speed reducer input shaft 25. However, since the rotational speed of the speed reducer input shaft 25 is larger than the speed reducer output shaft 28 (11 times in this embodiment), the durability of the rotary pump 51 may be reduced. Further, a sufficient discharge amount can be ensured even when connected to the decelerator output shaft 28 that has been decelerated. From these viewpoints, the rotary pump 51 is preferably driven by utilizing the rotation of the speed reducer output shaft 28.

  Moreover, although the cycloid pump was employ | adopted as the rotary pump 51 above, it is not restricted to this, All the rotary pumps driven using the rotation of the reduction gear output shaft 28 are employable. Furthermore, the rotary pump 51 may be omitted, and the lubricating oil may be circulated only by centrifugal force.

  Moreover, although the example which provided the curve board 26a, 26b of the deceleration part B by changing a 180 degree phase was shown, the number of the curve board can be set arbitrarily. For example, when three curved plates are provided, the 120 ° phase may be changed.

  In the above description, the motion conversion mechanism is configured by the inner pin 31 fixed to the reduction gear output shaft 28 and the through holes 30a provided in the curved plates 26a and 26b. Any configuration capable of transmitting the rotation to the hub wheel 32 can be employed. For example, you may comprise a motion conversion mechanism with the inner pin fixed to the curve board, and the hole formed in the reduction gear output shaft.

  The description of the operation in the present embodiment has been made by paying attention to the rotation of each member. Actually, power including torque is transmitted from the motor unit A to the rear wheel 14 as a drive wheel. Therefore, the power decelerated as described above is converted into high torque.

  Also, the case where power is supplied to the motor unit A to drive the motor unit and the power from the motor unit A is transmitted to the rear wheels 14 is shown. On the contrary, the vehicle decelerates or goes down the hill. In such a case, the power from the rear wheel 14 side may be converted into high-rotation and low-torque rotation by the speed reduction unit B and transmitted to the motor unit A, and the motor unit A may generate power. Furthermore, the electric power generated here can be stored in a battery and used as electric power for driving the motor unit A and electric power for operating other electric devices provided in the vehicle.

  In addition, a brake may be added to the in-wheel motor drive device 21. For example, in the configuration of FIG. 1, the casing 22 is extended in the axial direction to form a space on the inner side in the vehicle width direction of the rotor 23 b, a rotating member that rotates integrally with the rotor 23 b in this space, and the casing 22 cannot rotate. If a piston that can move in the axial direction and a cylinder that operates the piston are arranged, a parking brake that locks the rotor 23b by the piston and the rotating member when the vehicle is stopped can be provided. The brake may be a disc brake that sandwiches a flange formed on a part of the rotating member and a friction plate installed on the casing 22 side with a cylinder installed on the casing 22 side. A drum brake may be formed in which a drum is partially formed and a brake shoe is fixed to the casing 22 side to lock the rotating member by friction engagement and self-engagement.

  In the above description, the present invention is applied to a configuration in which a radial gap motor is used for the motor part A. However, the present invention is an axial gap motor in which the stator and the rotor are opposed to the motor part A via an axial gap. It is preferably applicable also when adopting.

  Furthermore, the in-wheel motor drive device according to the present invention includes not only the rear wheel drive type electric vehicle 11 having the rear wheel 14 as the drive wheel, but also the front wheel drive type electric vehicle having the front wheel 13 as the drive wheel, and the front wheel 13. It can also be applied to a four-wheel drive type electric vehicle using the rear wheel 14 as a drive wheel. In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and includes, for example, a hybrid vehicle.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 11 Electric vehicle 21 In-wheel motor drive device 22 Casing 25 Reduction gear input shaft 25a, 25b Eccentric part 26a, 26b Curved board (revolving member)
27 Outer pin (outer peripheral engagement member)
28 Reducer output shaft 31 Inner pin 51 Rotating pump 60 Outer pin housing 61 Rolling bearing 62 Outer ring (Raceway ring)
65 Needle rollers (rolling elements)
A Motor part B Reduction part C Wheel bearing part δ Clearance after assembly

Claims (5)

A casing for holding a motor part, a speed reduction part and a wheel bearing part, wherein the motor part rotationally drives a speed reducer input shaft having an eccentric part, and the speed reduction part decelerates rotation of the speed reducer input shaft to An in-wheel motor drive device that transmits to a reduction gear output shaft connected to a wheel bearing portion,
The speed reducer is rotatably held by the speed reducer input shaft and an eccentric portion of the speed reducer input shaft, and performs a revolving motion around the rotation axis as the speed reducer input shaft rotates. A revolving member, an outer peripheral engaging member that engages with an outer peripheral portion of the revolving member to cause the revolving member to generate a revolving motion, and the revolving motion of the revolving member is centered on a rotation axis of the speed reducer input shaft. A motion conversion mechanism that converts rotational motion and transmits it to the speed reducer output shaft, and a speed reduction portion lubrication mechanism that supplies lubricating oil to the speed reduction portion,
The in-wheel motor drive device according to claim 1, wherein the outer peripheral engaging member is rotatably supported by a rolling bearing, and the rolling bearing has a built-in clearance of 0 to 40 μm.   The in-wheel motor drive according to claim 1, wherein the bearing ring constituting the rolling bearing is made of bearing steel or carburized steel, is subjected to carbonitriding, and a surface portion has a remaining austenite amount of 20 to 35%. apparatus.   The in-wheel motor drive device according to claim 1 or 2, wherein the rolling elements constituting the rolling bearing are made of bearing steel, are subjected to carbonitriding, and the amount of retained austenite in the surface layer portion is 20 to 35%.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein the rolling bearing is a needle roller bearing.   The needle roller bearing is disposed between an outer ring having an outer raceway surface on an inner diameter surface, an inner raceway surface formed on the outer diameter surface of the outer peripheral engagement member, and between the outer raceway surface and the inner raceway surface. The in-wheel motor drive device according to claim 4 constituted by a plurality of needle rollers.

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