JP4920456B2 - In-wheel motor drive device - Google Patents

Description

  The present invention relates to an in-wheel motor drive device in which an output shaft of an electric motor and a wheel hub are coaxially connected via a reduction gear.

  Conventional in-wheel motor driving devices are described in, for example, Japanese Patent Application Laid-Open No. 2005-59684 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-32888 (Patent Document 2). The in-wheel motor drive device described in each of the above publications mainly includes a motor unit that generates a driving force, a reduction unit that reduces the rotation of the motor unit, and a wheel hub that transmits the output of the reduction unit to the wheels. Prepare for.

  In addition, a planetary gear type reduction mechanism (also referred to as “planetary reduction mechanism”, hereinafter the same) is employed in the reduction section described in Japanese Patent Application Laid-Open No. 2005-59684 (Patent Document 1). Generally, the reduction ratio of the planetary gear type reduction mechanism is set to about 1/3 to 1/6 from the viewpoint of the strength of the gears and the like.

  Here, the in-wheel motor drive device disposed below the suspension is required to be light and compact from the viewpoint of improving riding comfort. In order to satisfy these requirements while securing the torque necessary to drive the wheels, it is necessary to increase the speed of the motor unit and to employ a reduction unit with a high reduction ratio.

Therefore, the speed reduction part described in Japanese Patent Laid-Open No. 2001-32888 (Patent Document 2) has two planetary gear type speed reduction mechanisms arranged in series. The two planetary gear speed reduction mechanisms are disposed inside the rotor hub of the motor unit. Thereby, compared with the case of Unexamined-Japanese-Patent No. 2005-59684 (patent document 1), while being able to obtain a high reduction ratio, the axial direction dimension of an in-wheel motor drive device can be shortened.
JP 2005-59684 A JP 2001-32888 A

The reduction ratio r of the planetary gear type reduction mechanism is expressed by Equation 1 where n _{1 is} the number of teeth of the sun gear and n ₂ is the number of teeth of the internal gear. According to Equation 1, in order to increase the reduction ratio r, it is necessary to increase the number of teeth n ₂ of the internal gear. The number of teeth n ₂ of the internal gear is proportional to the diameter of the internal gear.

  However, when the planetary gear speed reduction mechanism is arranged inside the rotor hub as disclosed in JP 2001-32888 (Patent Document 2), the diameter of the internal gear is limited by the rotor hub and cannot be freely set. In particular, if the diameter of the rotor hub is reduced in order to reduce the radial dimension of the motor portion, the diameter of the internal gear may also be reduced and the required reduction ratio may not be obtained.

  SUMMARY OF THE INVENTION An object of the present invention is an in-wheel motor drive device that employs a planetary gear type reduction mechanism, and provides an in-wheel motor drive device that is reduced in weight and compact as a whole while increasing the speed reduction portion. It is to be.

  An in-wheel motor drive device according to the present invention includes a casing, a motor unit that rotationally drives the motor-side rotating member, a speed-reducing unit that decelerates the rotation of the motor-side rotating member and transmits the rotation to the wheel-side rotating member, and wheel-side rotation And a wheel hub fixedly connected to the member. The motor part includes a cylindrical stator fixed to the casing, a cylindrical part facing the stator with a radial gap, and a flange part extending radially inward from the inner peripheral surface of the cylindrical part. And a rotor that rotates integrally with the side rotation member. The speed reduction part is disposed inside the space delimited by the inner peripheral surface of the cylindrical part, and the first planetary speed reduction mechanism that decelerates the rotation of the motor side rotation member and the space delimited by the inner peripheral surface of the cylindrical part And a second planetary reduction mechanism that is disposed outside and decelerates the rotation of the first planetary reduction mechanism and transmits it to the wheel side rotation member. The outer diameter of the second planetary reduction mechanism is larger than the inner diameter of the cylindrical portion.

  By arranging the first planetary speed reduction mechanism inside the stator as in the above configuration, the in-wheel motor drive device can be made compact in the axial direction. Moreover, a high reduction ratio can be obtained by increasing the size of the second planetary reduction mechanism and disposing it outside the stator. As a result, it is possible to obtain an in-wheel motor drive device that is capable of reducing the speed of the speed reduction portion and reducing the overall weight and size.

  Preferably, the casing that holds the motor portion has an outer diameter smaller than an inner diameter of the cylindrical portion, and a small diameter portion that holds the first planetary reduction mechanism inside a space defined by the inner peripheral surface of the cylindrical portion; A large-diameter portion having an inner diameter dimension larger than the inner diameter dimension of the cylindrical portion and holding the second planetary reduction mechanism outside the space defined by the inner peripheral surface of the cylindrical portion.

  More preferably, the first planetary reduction mechanism includes a first sun gear that rotates integrally with the motor-side rotation member, a first internal gear that is fixed to the small diameter portion, the first sun gear, and the first inner gear. A plurality of first planetary gears that mesh with the gears, and a first planetary gear that rotates in association with the revolving motion of the first planetary gears, each of which has a plurality of first planetary gears rotatably held at one end. Have a carrier. The second planetary speed reduction mechanism includes a second sun gear that is fixed to the other end of the first planet carrier and rotates integrally, a second internal gear that is fixed to the large diameter portion, and a second sun gear. A plurality of second planetary gears meshed with the gear and the second internal gear, and a plurality of second planetary gears are rotatably held at one end, and connected to a wheel-side rotating member at the other end. And a second planet carrier that rotates in accordance with the revolution movement of the second planetary gear.

  Preferably, the outer member in which the first and second outer raceway surfaces are formed, the first inner raceway surface that is provided on the outer diameter surface of the wheel side rotation member and faces the first outer raceway surface, and the wheel hub A second inner raceway surface provided on the outer diameter surface and opposed to the second outer raceway surface; a space between the first outer raceway surface and the first inner raceway surface; and a second outer raceway surface and a second inner raceway surface; And a wheel hub bearing that rotatably supports the wheel hub with respect to the casing.

  As in the above configuration, the outer raceway surface is provided on the inner diameter surface of the outer member (casing), and the inner raceway surface is provided on the outer diameter surface of the wheel-side rotating member and the wheel hub. Since the outer ring can be omitted, the radial dimension of the wheel hub bearing can be reduced. Or when making the dimension of radial direction the same dimension, since the diameter of a rolling element can be enlarged, it becomes possible to increase load capacity. Furthermore, the effect of improving the assemblability by reducing the number of parts can be expected.

  According to the present invention, one of the planetary reduction mechanisms connected in series is arranged inside the stator, the other is enlarged and arranged outside the stator, thereby providing a reduction unit with a high reduction ratio, As a whole, an in-wheel motor drive device that is light and compact can be obtained.

  With reference to FIG. 2 and FIG. 3, the electric vehicle 11 provided with the in-wheel motor drive device which concerns on one Embodiment of this invention is demonstrated. 2 is a plan view of the electric vehicle 11, and FIG. 3 is a view of the electric vehicle 11 as viewed from the rear.

  Referring to FIG. 2, an electric vehicle 11 includes an in-wheel motor drive device that transmits driving force to a chassis 12, front wheels 13 as steering wheels, rear wheels 14 as drive wheels, and left and right rear wheels 14. 21. Referring to FIG. 3, the rear wheel 14 is housed inside a wheel housing 12 a of the chassis 12 and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12 b.

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

  The electric vehicle 11 needs to be provided with a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12 by providing an in-wheel motor drive device 21 for driving the left and right rear wheels 14 inside the wheel housing 12a. This eliminates the need to secure a wide cabin space and control the rotation of the left and right drive wheels.

  On the other hand, in order to improve the running stability of the electric vehicle 11, it is necessary to suppress the unsprung weight. In addition, in-wheel motor drive device 21 is required to be downsized in order to secure a wider cabin space. Therefore, as the in-wheel motor drive device 21, an in-wheel motor drive device 21 according to an embodiment of the present invention as shown in FIG. 1 is employed.

  With reference to FIG. 1, the in-wheel motor drive device 21 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of the in-wheel motor drive device 21.

  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. The motor part A and the speed reduction part B are housed in the casing 22 and are mounted in the wheel housing 12a of the electric vehicle 11 as shown in FIG.

  The motor part A is fixedly connected to the stator 23 as a stator fixed to the casing 22, the rotor 24 as a rotor that faces the stator 23 with a radial gap inside, and the rotor 24. This is a radial gap motor including a rotor-side rotating member 25 that rotates integrally with the rotor 24.

  The rotor 24 includes a large diameter cylindrical portion 24a, a small diameter cylindrical portion 24b, and a flange portion 24c extending in the radial direction between the large diameter cylindrical portion 24a and the small diameter cylindrical portion 24b. On the outer diameter surface of the large-diameter cylindrical portion 24a, a permanent magnet or a magnetic body (indicated by x in the figure) is provided at a position facing the stator 23. Further, the small-diameter cylindrical portion 24b is fitted to the motor-side rotating member 25 to rotate the rotor 24 and the motor-side rotating member 25 integrally.

  The motor-side rotation member 25 communicates with the motor unit A and the speed reduction unit B, and outputs the rotation of the motor unit A to the speed reduction unit B. One end of the motor side rotating member 25 is rotatably supported by the casing 22 and the other end thereof is rotatably supported by the wheel side rotating member 26 by radial rolling bearings 41a and 41b, respectively.

  The speed reduction unit B is configured by connecting first and second planetary speed reduction mechanisms 27 a and 27 b in series, and reduces the rotation of the motor side rotation member 25 and transmits it to the wheel side rotation member 26.

  The wheel side rotation member 26 is a hollow shaft having a flange portion 26a and a hollow portion 26b. The wheel-side rotating member 26 rotatably supports the motor-side rotating member 25 by a radial rolling bearing 41b on the inner diameter surface of the flange portion 26a. Moreover, it connects with the wheel hub 35 by the outer-diameter surface of the hollow part 26b, and the wheel side rotation member 26 and the wheel hub 35 rotate integrally.

  The casing 22 that holds the speed reduction portion B has an outer diameter smaller than an inner diameter of the large-diameter cylindrical portion 24a and a small-diameter portion 22b that is positioned inside a space defined by the inner peripheral surface of the large-diameter cylindrical portion 24a. And a large-diameter portion 22c that is larger than the inner-diameter size of the large-diameter cylindrical portion 24a and located outside the space defined by the inner peripheral surface of the large-diameter cylindrical portion 24a.

  The small-diameter portion 22b holds the first planetary reduction mechanism 27a, and the large-diameter portion 22c holds the second planetary reduction mechanism 27b. That is, the first planetary reduction mechanism 27a is disposed inside the space partitioned by the inner peripheral surface of the large diameter cylindrical portion 24a. On the other hand, the second planetary reduction mechanism 27b is disposed outside the space defined by the inner peripheral surface of the large diameter cylindrical portion 24a.

  The first planetary speed reduction mechanism 27a includes a first sun gear 28a, a first internal gear 29a, a plurality of first planetary gears 30a, and a first planet carrier 31a. The rotation of 25 is decelerated and transmitted to the second planetary decelerating mechanism 27b.

  The first sun gear 28 a rotates integrally with the motor side rotation member 25. In this embodiment, it is formed directly on the outer diameter surface of the motor-side rotating member 25, but the present invention is not limited to this, and a sun gear separate from the motor-side rotating member 25 is fitted and fixed to the motor-side rotating member 25. May be.

  The first internal gear 29 a is held by the small diameter portion 22 b of the casing 22. The first planetary gear 30a rotates and revolves while being engaged with the first sun gear 28a and the first internal gear 29a.

  The first planet carrier 31a has a plurality of first planet carrier shafts 32a inserted into the first planetary gear 30a at one end portion thereof, and is connected to the second planetary reduction mechanism 27b at the other end portion. Has been. And the 1st planet carrier 31a rotates with the revolution motion of the 1st planetary gear 30a.

  The first planet carrier 31a is rotatably supported on the motor-side rotating member 25 by radial needle roller bearings 42a and 42b. Further, in order to support the thrust load generated by the meshing of teeth when the gear constituting the planetary reduction mechanism is a helical gear, between the first sun gear 28a and the first planet carrier 31a, and Thrust needle roller bearings 43a and 43b are disposed between the wheel-side rotating member 26 and the first planet carrier 31a, respectively.

  One end of the first planet carrier shaft 32a is fixed to the first planet carrier 31a, and a retaining portion 34a for preventing the first planetary gear 30a from coming off is provided at the other end. And the 1st planetary gear 30a is rotatably supported via the radial needle roller bearing 33a.

  The second planetary speed reduction mechanism 27b includes a second sun gear 28b, a second internal gear 29b, a plurality of second planetary gears 30b, and a second planet carrier 31b, and the first planetary gear 31b. The rotation of the speed reduction mechanism 27a is decelerated and transmitted to the wheel side rotation member 26.

  The second sun gear 28b rotates integrally with the first planet carrier 31a. In this embodiment, the first planetary carrier 31a is directly formed on the outer diameter surface of the other side end portion, but the first planetary carrier 31a and the sun gear separate from the first planetary carrier 31a are not limited thereto. The planet carrier 31a may be fitted and fixed.

  The second internal gear 29 b is held by the large diameter portion 22 c of the casing 22. The outer diameter of the second internal gear 29b is set larger than the inner diameter of the cylindrical portion 24a of the rotor 24. The second planetary gear 30b rotates and revolves while being engaged with the second sun gear 28b and the second internal gear 29b.

  The second planet carrier 31b has a plurality of second planet carrier shafts 32b inserted into the second planetary gear 30b at one end portion thereof, and is connected to the motor-side rotating member 25 at the other end portion. Yes. Specifically, the flange portion 26a of the wheel side rotation member 26 functions as the second planet carrier 31b. And the 2nd planet carrier 31b rotates with the revolving motion of the 2nd planetary gear 30b.

  The second planet carrier shaft 32b has one end fixed to the second planet carrier 31b and the other end provided with a retaining portion 34b for preventing the second planetary gear 30b from coming off. And the 2nd planetary gear 30b is rotatably supported via the radial needle roller bearing 33b.

  The wheel hub bearing portion C includes a wheel hub 35 fixedly connected to the wheel-side rotating member 26 and a wheel hub bearing 36 that holds the wheel hub 35 rotatably with respect to the casing 22. The wheel hub 35 has a cylindrical hollow portion 35a and a flange portion 35b. The driving wheel 14 (not shown) is fixedly connected to the flange portion 35b by a bolt 35c. In addition, a sealing member 35 d is provided at the opening of the hollow portion 35 a in order to prevent dust from entering the in-wheel motor drive device 21.

  The wheel hub bearing 36 is a double-row angular ball bearing that employs balls 36e as rolling elements. As the raceway surfaces of the balls 36e, a first outer raceway surface 36a (right side in the figure) and a second outer raceway surface 36b (left side in the figure) are provided on the inner diameter surface of the outer member 22a. A first inner raceway surface 36c facing the surface 36a is provided on the outer diameter surface of the wheel-side rotating member 26, and a second inner raceway surface 36d facing the second outer raceway surface 36b is provided on the outer diameter surface of the wheel hub 35, respectively. ing. A plurality of balls 36e are arranged between the first outer raceway surface 36a and the first inner raceway surface 36c, and between the second outer raceway surface 36b and the second inner raceway surface 36d. The wheel hub bearing 36 includes a retainer 36f that holds the left and right balls 36e, and a sealing member 36g that prevents leakage of a lubricant such as grease enclosed in the bearing and dust from the outside. Including.

  The outer diameter surface of the wheel-side rotating member 26 and the inner diameter surface of the wheel hub 35 are plastically coupled by diameter expansion caulking. Specifically, the in-wheel motor drive device 21 is fixed, and a caulking jig (not shown) having an outer diameter slightly larger than the inner diameter of the hollow portion 26b of the wheel-side rotating member 26 is press-fitted into the hollow portion 26b. .

  Thereby, the wheel side rotation member 26 and the wheel hub 35 are plastically coupled at the plastic coupling portion 40. By fixedly connecting the wheel-side rotating member 26 and the wheel hub 35 by the above method, the coupling strength can be significantly increased as compared with the case of fixing by fitting. Thereby, the wheel hub 35 can be stably held.

  In the in-wheel motor drive device 21 configured as described above, the in-wheel motor drive device 21 can be made compact in the axial direction by arranging the first planetary reduction mechanism 27a inside the cylindrical portion 24a.

  In addition to the case where the entire region of the first planetary speed reduction mechanism 27a is located inside the space defined by the inner peripheral surface of the cylindrical portion 24a, a part of the first planetary speed reduction mechanism 27a as shown in FIG. Even if it is located inside the space defined by the inner peripheral surface of the cylindrical portion 24a, the effect of the present invention can be obtained.

  Further, the second planetary reduction mechanism 27b is arranged on the outside of the cylindrical portion 24a, and the outer diameter is made larger than the inner diameter of the cylindrical portion 24a. Compared with the mechanism 27b, the reduction ratio can be increased.

  The speed reduction ratio of the speed reduction part B as a whole is represented by the product of the speed reduction ratios of the first and second planetary speed reduction mechanisms 27a and 27b. Therefore, if the speed reduction ratio of the second planetary speed reduction mechanism 27b is increased, the speed reduction part The reduction ratio as a whole of B can be increased.

  In the embodiment shown in FIG. 1, the outer diameter of the casing 22 at the position of the motor part A is larger than the outer diameter of the second planetary reduction mechanism 27b. If the size of the second planetary speed reduction mechanism 27b is increased within a range not exceeding the motor portion A, an in-wheel motor drive device with a more compact and high reduction ratio can be obtained.

  As a result, the unsprung weight can be suppressed by adopting the in-wheel motor drive device 21 according to the above embodiment in the electric vehicle 11. As a result, the electric vehicle 11 having excellent running stability can be obtained.

  In addition, although description of the action | operation in said embodiment was performed paying attention to rotation of each member, the motive power containing a torque is actually transmitted from the motor part A to a driving wheel. Therefore, the power decelerated as described above is converted into high torque.

  In the description of the operation in the above embodiment, electric 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 the vehicle decelerates or goes down a hill, the power from the drive wheel side is converted into high-rotation low-torque rotation by the deceleration unit B and transmitted to the motor unit A. good. Furthermore, the electric power generated here may be stored in a battery and used later for driving the motor unit A or for operating other electric devices provided in the vehicle.

  Further, a brake can be added to the configuration of the above embodiment. For example, in the configuration of FIG. 1, the casing 22 is extended in the axial direction to form a space on the right side of the rotor 24 in the drawing, the rotating member that rotates integrally with the rotor 24, and the casing 22 is non-rotatable and axial. A parking brake may be provided in which a movable piston and a cylinder for operating the piston are disposed, and the rotor 24 is locked by fitting the piston and the rotating member when the vehicle is stopped.

  Alternatively, it may be a disc brake in which a flange formed on a part of a rotating member that rotates integrally with the rotor 24 and a friction plate installed on the casing 22 side are sandwiched by a cylinder installed on the casing 22 side. Furthermore, a drum brake can be used in which a drum is formed on a part of the rotating member, a brake shoe is fixed to the casing 22 side, and the rotating member is locked by friction engagement and self-engagement.

  In the above embodiment, the wheel side rotation member 26 and the wheel hub 35 are fixedly connected by diameter caulking. However, the present invention is not limited thereto, and the wheel side rotating member 26 and the wheel hub 35 may be fixedly connected by an arbitrary method. it can.

  Furthermore, although the electric vehicle 11 shown in FIG. 2 showed the example which used the rear wheel 14 as the driving wheel, it is not restricted to this, The front wheel 13 may be used as a driving wheel and may be a four-wheel driving vehicle. . In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

It is a schematic sectional drawing of the in-wheel motor drive device concerning one Embodiment of this invention. It is a top view of the electric vehicle which has the in-wheel motor drive device of FIG. FIG. 3 is a rear sectional view of the electric vehicle of FIG. 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Electric vehicle, 12 Chassis, 12a Wheel housing, 12b Suspension device, 13 Front wheel, 14 Rear wheel, 21 In-wheel motor drive device, 22 Casing, 22a Outer member, 22b Small diameter part, 22c Large diameter part, 23 Stator, 24 Rotor, 24a Large diameter cylindrical part, 24b Small diameter cylindrical part, 24c, 26a, 35b Flange part, 25 Motor side rotating member, 26 Wheel side rotating member, 26b, 35a Hollow part, 27a, 27b Planetary reduction mechanism, 28a, 28b Sun Gear, 29a, 29b Internal gear, 30a, 30b Planetary gear, 31a, 31b Planetary carrier, 32a, 32b Planetary carrier shaft, 33a, 33b, 42a, 42b Radial needle roller bearing, 34a, 34b Retaining part, 35 Wheel hub , 35c bolt, 35d, 36g sealing part , 36 wheel hub bearing, 36a, 36b outer raceway surface, 36c, 36d inner raceway surface, 36e ball, 36f retainer, 41a, 41b radial rolling bearing, 43a, 43 b thrust needle roller bearing.

Claims (4)

A casing,
A motor unit for rotationally driving the motor side rotating member;
A speed reducer that decelerates the rotation of the motor side rotating member and transmits it to the wheel side rotating member;
A wheel hub fixedly connected to the wheel side rotating member,
The motor part is
A cylindrical stator fixed to the casing;
A cylindrical portion facing the stator with a gap in the radial direction; and a flange portion extending radially inward from an inner circumferential surface of the cylindrical portion, and a rotor that rotates integrally with the motor-side rotation member. ,
The deceleration part is
A first planetary speed reduction mechanism that is disposed inside a space defined by the inner peripheral surface of the cylindrical portion and decelerates the rotation of the motor side rotation member;
A second planetary reduction mechanism that is arranged outside the space defined by the inner peripheral surface of the cylindrical portion, and that reduces the rotation of the first planetary reduction mechanism and transmits it to the wheel-side rotation member;
The in-wheel motor drive device, wherein an outer diameter of the second planetary reduction mechanism is larger than an inner diameter of the cylindrical portion. The casing holding the motor unit is
A small diameter portion having an outer diameter dimension smaller than an inner diameter dimension of the cylindrical portion and holding the first planetary reduction mechanism inside a space defined by an inner peripheral surface of the cylindrical portion;
The inner diameter dimension is larger than the inner diameter dimension of the cylindrical portion, and includes a large diameter portion that holds the second planetary reduction mechanism outside the space defined by the inner peripheral surface of the cylindrical portion. In-wheel motor drive device. The first planetary reduction mechanism includes a first sun gear that rotates integrally with the motor-side rotation member;
A first internal gear fixed to the small diameter portion;
A plurality of first planetary gears meshing with the first sun gear and the first internal gear;
A first planet carrier that rotatably holds each of the plurality of first planetary gears at one end, and rotates with the revolving motion of the first planetary gear;
The second planetary speed reduction mechanism includes a second sun gear fixed to the other end of the first planet carrier and rotating integrally therewith,
A second internal gear fixed to the large diameter portion;
A plurality of second planetary gears meshing with the second sun gear and the second internal gear;
Each of the plurality of second planetary gears is rotatably held at one end, and is connected to the wheel-side rotating member at the other end, and rotates in accordance with the revolving motion of the second planetary gear. The in-wheel motor drive device of Claim 2 which has two planetary carriers. An outer member having first and second outer raceways formed thereon;
A first inner raceway surface provided on an outer diameter surface of the wheel-side rotating member and facing the first outer raceway surface;
A second inner raceway surface provided on an outer diameter surface of the wheel hub and facing the second outer raceway surface;
A plurality of rolling elements disposed between the first outer raceway surface and the first inner raceway surface and between the second outer raceway surface and the second inner raceway surface;
The in-wheel motor drive device in any one of Claims 1-3 further equipped with the wheel hub bearing which supports the said wheel hub rotatably with respect to the said casing.

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