WO2017158933A1

WO2017158933A1 - In-wheel motor drive device

Info

Publication number: WO2017158933A1
Application number: PCT/JP2016/084813
Authority: WO
Inventors: 四郎田村; 真也太向
Original assignee: Ntn株式会社
Priority date: 2016-03-14
Filing date: 2016-11-24
Publication date: 2017-09-21

Abstract

A speed reduction section (31) includes: an input shaft (32) coupled to the rotating shaft (22) of a motor (21); an input gear (33) coupled to the input shaft; a circular cylindrical output shaft (41) coupled to an outer ring (12); and an output gear (40) coupled to the output shaft, and the speed reduction section (31) constitutes a drive transmission path for reducing the rotation of the input gear and outputting the reduced rotation to the output gear. The opposite ends of the output shaft are rotationally supported by: a first output shaft bearing (44) for rotationally supporting the outer diameter of the portion of the output shaft, which is located at one end thereof; and a second output shaft bearing (46) for rotationally supporting the inner diameter of the portion of the output shaft, which is located at the other end thereof.

Description

In-wheel motor drive device

The present invention relates to an in-wheel motor drive device that is disposed inside a wheel and drives the wheel, and more particularly to a structure that rotatably supports an output shaft of a speed reduction unit.

It is customary that an in-wheel motor that is disposed inside a wheel and drives the wheel includes a wheel hub bearing that rotatably supports the wheel hub, and the wheel hub is coupled to the wheel wheel to support the wheel load. For example, a wheel hub bearing described in Japanese Patent No. 5676142 (Patent Document 1) is installed in an annular gap between a cylindrical outer ring hub coupled to a wheel of a rear wheel and a spindle passed through a center hole of the outer ring hub. Is done.

A gear is provided on the outer periphery of the outer ring hub of Patent Document 1, and this gear meshes with the pinion. The pinion passes the rotation of the motor to the outer ring hub.

Japanese Patent No. 5676142

However, the present inventor has found that there is a further improvement in the conventional wheel hub bearing. That is, since the gear coupled to the outer periphery of the outer ring hub is supported by the wheel hub bearing, the gear may be displaced by an external force applied from the wheel. Undesirable displacement of the gears constituting the drive transmission path from the motor to the wheel hub causes uneven wear and the like, and the durability of the in-wheel motor deteriorates.

In view of the above circumstances, an object of the present invention is to provide a structure that stably supports the final gear of the speed reduction portion in the speed reduction portion that reduces the rotation of the motor and transmits the reduced speed to the wheel hub.

For this purpose, the in-wheel motor drive device of the present invention includes a motor unit for driving a wheel, a wheel hub bearing unit to which the wheel is attached, a reduction unit for reducing the rotation of the motor unit and transmitting it to the wheel hub bearing unit. The wheel hub bearing portion includes a rotating wheel that rotates integrally with the wheel, a fixed wheel that is disposed coaxially with the rotating wheel, and a plurality of rolling elements that are disposed in an annular gap between the rotating wheel and the fixed wheel. The speed reduction unit includes an input shaft coupled to the motor rotation shaft of the motor unit, an input gear coupled to the input shaft, an output shaft coupled to the rotating wheel of the wheel hub bearing unit, and an output gear coupled to the output shaft. A first output shaft bearing that rotationally supports one end side of the output shaft and a second output shaft bearing that rotationally supports the other end side of the output shaft As a result, both ends of the output shaft are rotationally supported. .

According to the present invention, in addition to the wheel hub bearing portion, the speed reduction portion includes the output shaft coupled to the rotating wheel, the first output shaft bearing that rotatably supports the end portion of the output shaft, and the first output shaft. Since the second output shaft bearing that rotatably supports the remaining end portion of the output shaft positioned on the side opposite to the bearing is included, the output shaft can be stably supported at both ends. Therefore, even when an external force is applied from the wheel to the outer ring, the displacement of the output shaft can be suppressed, and uneven wear of the gear of the speed reduction unit can be prevented.

Rotating wheel and fixed ring of wheel hub bearing part are composed of outer ring and inner ring of rolling bearing. In one embodiment, the rotating wheel is an outer ring, and the fixed ring is included in a fixed shaft that is passed through the center hole of the outer ring.

The arrangement location of the first output shaft bearing and the second output shaft bearing is not particularly limited. As one embodiment, the first output shaft bearing rotatably supports the outer diameter on one end side of the output shaft, and the second output shaft bearing rotatably supports the inner diameter on the other end side of the output shaft. According to this embodiment, in addition to the wheel hub bearing portion, the speed reduction portion includes the cylindrical output shaft coupled to the outer ring, the first output shaft bearing that rotatably supports the end portion of the output shaft, and the first Since the second output shaft bearing that rotatably supports the remaining end portion of the output shaft located on the side opposite to the output shaft bearing is included, the output shaft can be stably supported at both ends. Therefore, even when an external force is applied from the wheel to the outer ring, the displacement of the output shaft can be suppressed, and uneven wear of the gear of the speed reduction unit can be prevented.

Further, according to the present embodiment, the first output shaft bearing that rotatably supports the outer diameter of one end side of the output shaft, and the second output shaft bearing that rotatably supports the inner diameter of the other end side of the output shaft. Since both ends are rotationally supported, the output shaft is stably supported by both the inner diameter and the outer diameter. Therefore, even when an external force is applied from the wheel to the outer ring, the displacement of the output shaft can be suppressed, and uneven wear of the gear of the speed reduction unit can be prevented. The structure of the first and second output shaft bearings is not particularly limited, but is preferably a rolling bearing. The first and second output shaft bearings are, for example, ball bearings, cylindrical roller bearings, rolling bearings, radial bearings, and angular bearings. The first output shaft bearing that rotates and supports the outer diameter of the output shaft is, for example, an output shaft having an outer peripheral surface, and the first output shaft bearing is disposed on the outer diameter side of the outer peripheral surface so that the output shaft can rotate freely. It means to support. The second output shaft bearing that rotationally supports the inner diameter of the output shaft is, for example, an end portion of the output shaft that is formed in a hollow cylindrical shape and has an inner peripheral surface, and the second output shaft bearing is on the inner diameter side of the inner peripheral surface. It is arranged to support the output shaft rotatably.

As a preferred embodiment of the present invention, a first annular step is formed on the outer periphery of one end portion of the output shaft so that the diameter near the center in the axial direction is large, and the first output shaft bearing is axially formed by the first annular step. Defined position. According to this embodiment, the displacement of the first output shaft bearing can be regulated so that the first annular step is directed in one axial direction and is not displaced in the other axial direction.

As a preferred embodiment of the present invention, a second annular step is formed on the inner periphery of the other end portion of the output shaft so that the diameter near the center in the axial direction is a small diameter, and the second output shaft bearing is axially formed by the second annular step. Defined position. According to this embodiment, the displacement of the second output shaft bearing can be restricted so that the second annular step is not displaced in the axial direction while being directed in the other axial direction.

In a more preferred embodiment of the present invention, the output gear is a helical gear. According to this embodiment, the tooth contact can be improved. Further, the axial force acting on the helical gear can be received by the first and second output shaft bearings fixed so as not to be displaced in the axial direction.

The member that supports the first and second output shaft bearings is not particularly limited. The first and second output shaft bearings are supported by, for example, a casing of the in-wheel motor drive device. As an embodiment of the present invention, the second output shaft bearing is provided between the inner peripheral surface of the output shaft and the outer peripheral surface of the fixed shaft. According to this embodiment, the output shaft can be supported by the fixed shaft having a higher strength than the casing of the in-wheel motor drive device. As another embodiment, a cylindrical portion may be provided in the casing, and the second output shaft bearing may be supported by the cylindrical portion.

As a preferred embodiment of the present invention, the outer ring is disposed on one axial direction of the wheel hub bearing portion, the output shaft is disposed on the other axial direction of the wheel hub bearing portion, and the inner peripheral surface of one end portion of the output shaft is the axial line of the outer ring. The outer ring and the output shaft are coupled to each other so as to cover the outer peripheral surface of the other end portion in the direction, the first output shaft bearing rotatably supports the outer peripheral surface of the one end portion of the output shaft, and the second output shaft bearing is the output shaft The inner peripheral surface of the other end is rotatably supported. According to this embodiment, a 1st output-shaft bearing can be arrange | positioned in the coupling | bond location of the outer ring | wheel of a wheel hub bearing part and the output shaft of a deceleration part. Accordingly, the axial position of the first output shaft bearing can be overlapped with the axial position of the outer ring, and the total axial dimension of the outer ring and the output shaft can be shortened. As another embodiment, the first and second output shaft bearings may be arranged at locations away from the outer ring of the outer ring hub bearing portion in the axial direction.

As a further preferred embodiment of the present invention, the output gear is provided on the outer periphery of the other end portion in the axial direction of the output shaft, and the axial position of the output gear overlaps with the axial position of the second output shaft bearing. According to this embodiment, the axial dimension of the output shaft can be shortened. As another embodiment, an output gear may be disposed between the first output shaft bearing and the second output shaft bearing.

As one embodiment of the present invention, a first output shaft bearing includes a radial surface including an outer raceway surface on the outer diameter side, an inner raceway surface on the inner diameter side, and a plurality of rolling elements that roll on the outer raceway surface and the inner raceway surface. This is a bearing, and the maximum outer diameter of the outer raceway surface is smaller than the outer diameter of the output gear. According to this embodiment, the diameter dimension of the first output shaft bearing is reduced, and as a result, the diameter dimension of the wheel hub bearing portion can be further reduced. Therefore, it is possible to secure an arrangement space for the wheel hub bearing portion in the inner space of the wheel. The maximum outer diameter of the outer raceway surface means a portion having the largest outer diameter on the outer raceway surface. When the outer ring raceway surface is a groove having a semicircular cross section, for example, the outer diameter at the groove bottom is the maximum outer diameter of the outer raceway surface. In another embodiment, the maximum outer diameter of the outer raceway surface may be larger than the outer diameter of the output gear.

As another embodiment of the present invention, the fixed ring is an outer ring, and the rotating ring is an inner ring disposed in the center hole of the outer ring. The inner ring may be an annular member or a solid cylindrical shaft.

As a preferred embodiment of the present invention, the first output shaft bearing and the second output shaft bearing are supported by the casing of the speed reduction unit. Specifically, for example, an inner peripheral surface is formed in the casing, the outer peripheral surface of the output shaft is opposed to the inner peripheral surface of the casing, and the first output shaft bearing and / or the second output shaft bearing is output to the casing inner peripheral surface. Install between the outer peripheral surface of the shaft. Alternatively, the first output shaft bearing and / or the second output shaft bearing may be installed between the casing outer peripheral surface and the output shaft inner peripheral surface. Or you may install a 1st output-shaft bearing and / or a 2nd output-shaft bearing in another location.

Thus, according to the present invention, it is possible to stably support the output gear which is the final gear of the speed reduction unit. Therefore, even if an external force is applied from the wheel to the outer ring, the displacement of the output shaft is suppressed to prevent uneven wear or the like of the gear of the speed reduction unit, thereby improving the durability of the in-wheel motor drive device.

It is an expanded sectional view showing the in-wheel motor drive which becomes a 1st embodiment of the present invention cut and developed by a predetermined plane. It is a rear view which shows the inside of the in-wheel motor drive device of the embodiment with a wheel. It is sectional drawing which shows the in-wheel motor drive device of the embodiment with a suspension apparatus. It is an expanded sectional view which cuts and unfolds a 2nd embodiment of the present invention on a predetermined plane. It is an expanded sectional view which cuts and expands a 3rd embodiment of the present invention at a predetermined plane. It is an expanded sectional view showing a 4th embodiment of the present invention cut and developed by a predetermined plane.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a developed cross-sectional view showing the in-wheel motor drive device according to the first embodiment of the present invention cut and developed on a predetermined plane. FIG. 2 is a rear view showing the inside of the in-wheel motor drive device of the first embodiment together with the wheels, and the motor unit 21 and the rear portion 43b of the main body casing 43 are removed from the in-wheel motor drive device 10 in FIG. The state which looked at the inside of the in-wheel motor drive device 10 from the paper surface right side of FIG. 1 is represented. The predetermined plane shown in FIG. 1 includes a plane including the axis M and the axis Nf, a plane including the axis Nf and the axis Nl, and a plane including the axis Nl and the axis O shown in FIG. It is a connected development plane.

As shown in FIG. 1, the in-wheel motor drive device 10 includes a wheel hub bearing portion 11 connected to the center of the wheel wheel W represented by a virtual line, a motor portion 21 that drives the wheel wheel W of the wheel, and a motor portion. Is provided in a wheel housing (not shown) of the electric vehicle. The motor unit 21 and the speed reduction unit 31 are not arranged coaxially with the axis O of the wheel hub bearing unit 11 but are offset from the axis O of the wheel hub bearing unit 11 as shown in FIG. The wheel wheel W is well known, and a tire T is fitted on the outer periphery of the wheel wheel W, and is disposed on the front, rear, left and right sides of the vehicle body. Such a vehicle body constitutes an electric vehicle together with the wheels. The in-wheel motor drive device 10 can drive an electric vehicle at a speed of 0 to 180 km / h on a public road.

The wheel hub bearing portion 11 is disposed in an annular gap between the outer ring 12 as a wheel hub coupled with the wheel wheel W, the inner fixing member 13 passed through the center hole of the outer ring 12, and the outer ring 12 and the inner fixing member 13. A plurality of rolling elements 14 are included to constitute an axle. The inner fixing member 13 includes a non-rotating fixing shaft 15, a pair of inner races 16, and a retaining nut 17. The fixed shaft 15 has a root portion 15r having a larger diameter than the tip portion 15e. The inner race 16 is fitted to the outer periphery of the fixed shaft 15 between the root portion 15r and the tip portion 15e. The retaining nut 17 is screwed into the tip portion 15e of the fixed shaft 15, and the inner race 16 is fixed between the retaining nut 17 and the root portion 15r.

The fixed shaft 15 extends along the axis O, and the tip portion 15e of the fixed shaft 15 is directed outward in the vehicle width direction. The root portion 15 r of the fixed shaft 15 protrudes inward in the vehicle width O direction from the outer ring 12 and faces the back surface portion 43 b of the main body casing 43. The root portion 15r is attached and fixed to the back surface portion 43b inside the main body casing 43 by a bolt 13c. Further, the root portion 15r is connected to the carrier 18 outside the main body casing 43 by a bolt 13b.

The rolling elements 14 are arranged in double rows with a separation in the direction of the axis O. The outer peripheral surface of one inner race 16 in the axis O direction constitutes the inner raceway surface of the rolling elements 14 in the first row, and faces one inner peripheral surface of the outer ring 12 in the axis O direction. The outer peripheral surface of the other inner race 16 in the direction of the axis O constitutes the inner raceway surface of the rolling elements 14 in the second row, and faces the other inner peripheral surface of the outer ring 12 in the direction of the axis O. In the following description, the vehicle width direction outer side (outboard side) is also referred to as one axial direction, and the vehicle width direction inner side (inboard side) is also referred to as the other axial direction. The left-right direction in FIG. 1 corresponds to the vehicle width direction. The inner peripheral surface of the outer ring 12 constitutes the outer raceway surface of the rolling element 14.

A flange portion 12f is formed at one end of the outer ring 12 in the axis O direction. The flange portion 12f constitutes a coupling seat portion for coupling coaxially with a brake rotor and a spoke portion Ws of the wheel W which are not shown. The outer ring 12 is coupled to the wheel wheel W at the flange portion 12f and rotates integrally with the wheel wheel W.

As shown in FIG. 1, the motor unit 21 has a motor rotating shaft 22, a rotor 23, a stator 24, a motor casing 25, and a motor casing cover 25v, and sequentially from the axis M of the motor unit 21 to the outer diameter side in this order. Be placed. The motor unit 21 is a radial gap motor of an inner rotor and outer stator type, but may be of other types. For example, although not shown, the motor unit 21 may be an axial gap motor.

The axis M that is the rotation center of the motor rotation shaft 22 and the rotor 23 extends in parallel with the axis O of the wheel hub bearing portion 11. That is, the motor unit 21 is disposed offset from the axis O of the wheel hub bearing unit 11. Most of the axial positions of the motor unit 21 excluding the tip of the motor rotating shaft 22 do not overlap with the axial positions of the inner fixing member 13 as shown in FIG. The motor casing 25 has a substantially cylindrical shape. The motor casing 25 is coupled to the back surface portion 43b of the main body casing 43 at one end in the axis M direction, and is sealed with a bowl-shaped motor casing cover 25v at the other end in the axis M direction. Both end portions of the motor rotating shaft 22 are rotatably supported by the motor casing 25 via rolling

bearings

27 and 28. The motor unit 21 drives the outer ring 12.

The speed reduction unit 31 includes an input shaft 32, an input gear 33, an intermediate gear 34, an intermediate shaft 35, an intermediate gear 36, an intermediate gear 37, an intermediate shaft 38, an intermediate gear 39, an output gear 40, an output shaft 41, and a main body casing 43. Have. The input shaft 32 is a cylindrical body having a larger diameter than the distal end portion 22 e of the motor rotation shaft 22, and extends along the axis M of the motor portion 21. The distal end portion 22 e is received in the center hole at the other end portion in the axis M direction of the input shaft 32, and the input shaft 32 is coupled coaxially with the motor rotation shaft 22. Both ends of the input shaft 32 are supported by the main body casing 43 via rolling

bearings

42a and 42b. The input gear 33 is an external gear having a smaller diameter than the motor unit 21 and is coupled to the input shaft 32 coaxially. Specifically, the input gear 33 is integrally formed on the outer periphery of the central portion of the input shaft 32 in the axis M direction. In FIG. 2 and subsequent figures, each tooth of the gear is not represented, and the gear is represented by a tip circle.

The output shaft 41 is a cylindrical body having a diameter larger than that of the outer ring 12 and extends along the axis O of the wheel hub bearing portion 11. The other end of the outer ring 12 in the direction of the axis O is received in the center hole of one end of the output shaft 41 in the direction of the axis O, and the output shaft 41 is coupled to the outer ring 12 coaxially. Specifically, a spline groove 41s is formed on the inner peripheral surface of the output shaft 41, a spline groove 12s is formed on the outer peripheral surface of the other end of the outer ring 12 in the axis O direction, and the

spline grooves

41s and 12s are spline-fitted. . Such spline fitting realizes torque transmission between the output shaft 41 and the outer ring 12 and allows relative movement between the two.

The one end of the output shaft 41 in the direction of the axis O is supported by the main body casing 43 via a rolling bearing 44. The other end of the output shaft 41 in the direction of the axis O is supported by a root portion 15r of the fixed shaft 15 via a rolling bearing 46. The output gear 40 is an external gear and is coupled to the output shaft 41 coaxially. Specifically, the output gear 40 is integrally formed on the outer periphery of the other end of the output shaft 41 in the axis O direction.

The two

intermediate shafts

35 and 38 extend in parallel with the input shaft 32 and the output shaft 41. That is, the speed reduction unit 31 is a four-axis parallel shaft gear reducer, and the axis O of the output shaft 41, the axis Nf of the intermediate shaft 35, the axis Nl of the intermediate shaft 38, and the axis M of the input shaft 32 are parallel to each other. In other words, it extends in the vehicle width direction.

The vehicle longitudinal direction position of each axis will be described. As shown in FIG. 2, the axis M of the input shaft 32 is arranged in front of the vehicle with respect to the axis O of the output shaft 41. The axis Nf of the intermediate shaft 35 is disposed in front of the vehicle with respect to the axis M of the input shaft 32. The axis Nl of the intermediate shaft 38 is arranged in front of the vehicle with respect to the axis O of the output shaft 41 and behind the axis M of the input shaft 32. As a modification (not shown), the input shaft 32, the intermediate shaft 35, the intermediate shaft 38, and the output shaft 41 may be arranged in this order in the vehicle front-rear direction. This order is also the order in which the driving force is transmitted.

Describing the vertical position of each axis, the axis M of the input shaft 32 is arranged above the axis O of the output shaft 41. The axis Nf of the intermediate shaft 35 is disposed above the axis M of the input shaft 32. The axis Nl of the intermediate shaft 38 is disposed above the axis Nf of the intermediate shaft 35. The plurality of

intermediate shafts

35 and 38 need only be disposed above the input shaft 32 and the output shaft 41, and the intermediate shaft 35 may be disposed above the intermediate shaft 38 as a modification (not shown). Alternatively, as a modification not shown, the output shaft 41 may be disposed above the input shaft 32.

The intermediate gear 34 and the intermediate gear 36 are external gears, and are coupled coaxially with the central portion of the intermediate shaft 35 in the axis Nf direction as shown in FIG. Both ends of the intermediate shaft 35 are supported by the main body casing 43 via rolling

bearings

45a and 45b. The intermediate gear 37 and the intermediate gear 39 are external gears, and are coupled coaxially with the central portion of the intermediate shaft 38 in the direction of the axis Nl. Both ends of the intermediate shaft 38 are supported by the main body casing 43 via rolling

bearings

48a and 48b.

The main body casing 43 forms an outer shell of the speed reduction part 31 and the wheel hub bearing part 11, is formed in a cylindrical shape, and surrounds axes O, Nf, Nl and M extending in parallel to each other as shown in FIG. The main body casing 43 is accommodated in the inner space of the wheel wheel W. The inner space of the wheel W is defined by the inner peripheral surface of the rim portion Wr and the spoke portion Ws that is coupled to one end of the rim portion Wr in the axis O direction. One area in the axial direction of the wheel hub bearing portion 11, the speed reduction portion 31, and the motor portion 21 is accommodated in the inner space region of the wheel wheel W. Further, the other axial region of the motor unit 21 protrudes from the wheel W to the other axial direction. Thus, the wheel wheel W accommodates most of the in-wheel motor drive device 10.

Referring to FIG. 2, the main body casing 43 protrudes downward at a position away from the axis O of the output gear 40 in the longitudinal direction of the vehicle, specifically, directly below the axis M of the input gear 33. This protruding portion forms an oil tank 47. On the other hand, a space S is secured between a portion 43c of the main body casing 43 directly below the axis O and a lower portion of the rim portion Wr. A suspension member 71 extending in the vehicle width direction is disposed in the space S, and the vehicle width direction outer end 72 of the suspension member 71 and the inner fixing member 13 are connected to each other via the ball joint 60 so as to be freely directional.

The main body casing 43 has a cylindrical shape, and as shown in FIG. 1, the input shaft 32, the input gear 33, the intermediate gear 34, the intermediate shaft 35, the intermediate gear 36, the intermediate gear 37, the intermediate shaft 38, the intermediate gear 39, and the output gear. 40 and the output shaft 41 are accommodated, and the other end of the wheel hub bearing portion 11 in the axis O direction is covered. Lubricating oil is enclosed in the main body casing 43. The input gear 33, the intermediate gear 34, the intermediate gear 36, the intermediate gear 37, the intermediate gear 39, and the output gear 40 are helical gears.

As shown in FIG. 1, the main body casing 43 has a substantially flat front portion 43 f that covers one side in the axial direction of the cylindrical portion of the speed reduction portion 31 and a substantially flat surface that covers the other side in the axial direction of the cylindrical portion of the speed reduction portion 31. It includes a back portion 43b. The back surface portion 43 b is coupled to the motor casing 25. Further, the back surface portion 43 b is coupled to a suspension member (not shown) such as an arm or a strut via the carrier 18. Thereby, the in-wheel motor drive device 10 is supported by the suspension member.

An opening 43p through which the outer ring 12 passes is formed in the front portion 43f. The opening 43p is provided with a sealing material 43s for sealing an annular gap with the outer ring 12. For this reason, the outer ring 12 serving as a rotating body is accommodated in the main body casing 43 except for one end portion in the axis O direction.

The small-diameter input gear 33 and the large-diameter intermediate gear 34 are arranged on one side in the axial direction of the speed reduction unit 31 and mesh with each other. The small-diameter intermediate gear 36 and the large-diameter intermediate gear 37 are arranged on the other side in the axial direction of the speed reduction portion 31 and mesh with each other. The small-diameter intermediate gear 39 and the large-diameter output gear 40 are disposed on one side in the axial direction of the speed reduction unit 31 and mesh with each other. Thus, the input gear 33, the plurality of

intermediate gears

34, 36, 37, 39 and the output gear 40 mesh with each other, and the input gear 33 passes through the plurality of

intermediate gears

34, 36, 37, 39 to the output gear 40. To reach the drive transmission path. The rotation of the input shaft 32 is decelerated by the intermediate shaft 35, the rotation of the intermediate shaft 35 is decelerated by the intermediate shaft 38, and the rotation of the intermediate shaft 38 is decelerated by the output shaft 41. Is done. Thereby, the deceleration part 31 ensures a sufficient reduction ratio. Among the plurality of intermediate gears, the intermediate gear 34 is a first intermediate gear positioned on the input side of the drive transmission path. Among the plurality of intermediate gears, the intermediate gear 39 is a final intermediate gear located on the output side of the drive transmission path.

As shown in FIG. 2, the output shaft 41, the intermediate shaft 38, and the input shaft 32 are arranged at intervals in the vehicle front-rear direction in this order. Further, the intermediate shaft 35 and the intermediate shaft 38 are disposed above the input shaft 32 and the output shaft 41. According to the first embodiment, the intermediate shaft can be disposed above the outer ring 12 that serves as a wheel hub, and a space for the oil tank 47 can be secured below the outer ring 12, or the space S can be formed directly below the outer ring 12. Can be secured. Accordingly, the turning shaft extending in the vertical direction can be provided so as to intersect the space S, and the wheel wheel W and the in-wheel motor drive device 10 can be suitably turned around the turning shaft.

Further, according to the present embodiment, as shown in FIG. 2, the axis M of the motor portion 21 is arranged offset from the axis O of the wheel hub bearing portion in the vehicle front-rear direction, and the axis Nf of the intermediate shaft 35 is the wheel hub bearing. The axis Nl of the intermediate shaft 38 is offset upward from the axis O of the wheel hub bearing part. Thereby, the space S can be ensured between the portion 43c directly below the axis O in the in-wheel motor drive device 10 and the lower portion of the rim portion Wr. And the steering axis of a wheel can be arranged so that it may intersect with wheel wheel W, and the turning characteristic of a wheel improves.

Further, according to the present embodiment, as shown in FIG. 1, the input shaft 32 and the output shaft 41 extend in the vehicle width direction, and as shown in FIG. 2, the input gear 33 and the output gear 40 are set to stand up and down. The lower edge 40b of the output gear 40 is disposed below the lower edge 33b of the input gear 33. As a result, the input gear 33 that rotates at a high speed is not immersed in the lubricating oil stored in the lower portion of the speed reduction unit 31 inside the main body casing 43, and the stirring resistance of the input gear 33 can be avoided.

Further, according to the present embodiment, as shown in FIG. 2, the plurality of

intermediate shafts

35, 38 are arranged adjacent to each other above the input shaft 32 and are supplied with driving torque from the input shaft 32. , And a final intermediate shaft 38 that is disposed adjacent to the output shaft 41 and supplies driving torque to the output shaft 41, and includes the input shaft 32, the first intermediate shaft 35, the final intermediate shaft 38, and the output shaft 41. Are the center of the input shaft (axis line M), the center of the first intermediate shaft 35 (axis line Nf), the center of the final intermediate shaft 38 (axis line Nl) and the output shaft in the axial direction of the plurality of

intermediate shafts

35, 38. The reference lines sequentially connecting the centers of 41 (axis O) are arranged so as to draw an inverted U-shape. As a result, the overall arrangement of the plurality of shafts and gears constituting the drive transmission path is reduced in size, and the plurality of shafts and gears can be accommodated in the wheel wheel W.

Further, according to the present embodiment, as shown in FIG. 1, the outer ring 12 that becomes a wheel hub is a cylindrical body, and the wheel hub bearing portion 11 is disposed in the center hole of the outer ring 12 to rotatably support the outer ring 12. The fixed shaft 15 is further included. Thereby, the output gear 40 can be coaxially coupled to the outer diameter side of the outer ring 12. Then, the driving force can be transmitted to the outer ring 12 from the intermediate shaft 38 arranged to be offset with respect to the outer ring 12.

The main body casing 43 further accommodates a pump shaft 51, rolling

bearings

52a and 52b, a pump gear 53, and an oil pump 54 as shown in FIG. The axis P of the pump shaft 51 extends in parallel with the axis O of the output shaft 41. The pump shaft 51 is disposed away from the output shaft 41 in the vehicle front-rear direction, is supported rotatably at both ends in the axis P direction via rolling

bearings

52a and 52b, and is coaxial with the pump gear 53 at the center in the axis P direction. Join. The pump gear 53 meshes with the output gear 40.

The oil pump 54 is disposed further on the other side in the axis P direction than the rolling bearing 52 b and is provided on the other end in the axis P direction of the pump shaft 51. When the oil pump 54 is driven by the output gear 40, the oil pump 54 sucks lubricating oil from the oil tank 47 and discharges the sucked lubricating oil to the motor unit 21 and the speed reducing unit 31. Thereby, the motor part 21 and the deceleration part 31 are lubricated.

2, the pump shaft 51 of the present embodiment is disposed below the input shaft 32, and the oil tank 47 is disposed below the pump shaft 51. The oil pump 54 (FIG. 1) is disposed substantially coaxially with the pump shaft 51 and pumps the lubricating oil stored in the oil tank 47 directly above the oil tank 47. The pump shaft 51 and the oil tank 47 are disposed in front of the output shaft 41 in the vehicle. When the wheel is driven by the in-wheel motor drive device 10 and the vehicle travels, the oil tank 47 receives traveling wind from the front of the vehicle and is cooled by air.

Next, the connection structure of the main body casing 43 and the inner fixing member 13 will be described.

The inner fixing member 13 is cantilevered so that one end in the axial direction becomes a free end and the other end in the axial direction becomes a fixed end. Specifically, as shown in FIG. 1, among the fixed shafts 15 of the inner fixing member 13, the other end surface 15n in the axis O direction faces one wall surface 43bm in the axis O direction of the back surface portion 43b. The base portion 15r of the fixed shaft 15 is provided with a protruding portion 15p that protrudes in the outer diameter direction. The protruding portion 15p is fixed to the one wall surface 43bm in the axis O direction of the back surface portion 43b. The one wall surface 43 bm in the axis O direction refers to a wall surface that faces the outside in the vehicle width direction among the back surface portion 43 b that becomes the wall portion of the main body casing 43, and is an inner wall surface of the main body casing 43.

The protruding portion 15p is fixed to the back surface portion 43b by a bolt 13c. A female screw hole 43t directed in one axial direction is formed in one wall surface 43bm in the axial O direction of the back surface portion 43b. The bolt 13c extends parallel to the axis O, has a head portion 13cd on one side in the axis O direction, has a shaft portion 13ct on the other side in the axis O direction, and the shaft portion 13ct penetrates the protruding portion 15p and is screwed into the female screw hole 43t. Match.

Next, a connection structure between the in-wheel motor drive device 10 and the suspension member 71 will be described with reference to FIG.

FIG. 3 is a cross-sectional view showing a connection structure between the in-wheel motor drive device 10 and the suspension device 70, and shows a state seen in the vehicle front-rear direction. The spoke portion Ws of the wheel wheel W and the brake rotor BD are attached and fixed to the flange portion 12 f of the outer ring 12. A caliper (not shown) is attached and fixed to the vehicle rear portion of the main body casing 43. The caliper brakes the brake rotor BD. In order to facilitate understanding of the present invention, the brake rotor BD disposed in the inner space of the wheel W is omitted in the drawings excluding FIG. The outer ring 12 is disposed on the outer side in the vehicle width direction when viewed from the wheel center of the wheel wheel W (the center from one end to the other end of the wheel wheel W on the axis O).

The suspension device 70 is a strut suspension device and includes two

suspension members

71 and 76. The suspension member 76 is a strut extending in the vertical direction, and includes a shock absorber 76s and can be expanded and contracted in the vertical direction. A coil spring (not shown) is coaxially disposed on the outer periphery of the upper end region 77 of the suspension member 76 to relieve the vertical axial force acting on the suspension member 76. The upper end of the suspension member 76 supports a vehicle body side member (not shown).

The suspension member 71 is a lower arm (suspension arm) that is disposed below the suspension member 76 and extends in the vehicle width direction. The end portions of the suspension member 71 constitute a vehicle width direction outer end 72 and a vehicle width direction inner end 73. The suspension member 71 is connected to the in-wheel motor drive device 10 via the ball joint 60 at the outer end 72 in the vehicle width direction. The suspension member 71 is connected to a vehicle body side member (not shown) at an inner end 73 in the vehicle width direction. The suspension member 71 can swing in the vertical direction with the vehicle width direction inner end 73 as a base end and the vehicle width direction outer end 72 as a free end. The vehicle body side member refers to a member that is attached to the vehicle body side as viewed from a member to be described.

The ball joint 60 includes a ball stud 61 and a socket 62. The ball stud 61 extends in the vertical direction, and has a ball portion 61b formed at the upper end and a stud portion 61s formed at the lower end. The socket 62 is provided in the inner side fixing member 13, and accommodates the ball | bowl part 61b so that sliding is possible. The stud portion 61s penetrates the vehicle width direction outer end 72 in the vertical direction. A male screw is formed on the outer periphery of the lower end of the stud portion 61s, and the stud portion 61s is attached and fixed to the suspension member 71 by screwing a nut 72n from below.

As shown in FIG. 1, the carrier 18 is coupled to the fixed shaft 15 and the back surface portion 43b by bolts 13b. A protruding portion 15 p is formed at the base portion 15 r of the fixed shaft 15. A female screw hole 15t is formed in the protruding portion 15p. The bolt 13b is inserted into the through hole of the carrier 18 and the through hole of the intermediate member 19 from the other in the axis O direction to the other, and the shaft portion of the bolt 13b is screwed into the female screw hole 15t.

An intermediate member 19 is interposed between the protruding portion 15p and the carrier 18. The intermediate member 19 is fitted into an opening 43q formed in the back surface portion 43b. A sealing material 49 is provided on the entire circumference of the intermediate member 19. The sealing material 49 seals the annular gap between the opening 43q and the intermediate member 19.

The fixed shaft 15 is arranged inside the main body casing 43 and the carrier 18 is arranged outside the main body casing 43 with the back surface portion 43b which is the wall portion of the main body casing 43 as a boundary.

The carrier 18 has an upper arm portion 18a extending upward and a lower arm portion 18b extending downward as shown in FIG. The upper arm portion 18a protrudes upward beyond the wheel hub bearing portion 11, and is attached and fixed to the lower end portion 76b of the suspension member 76 (strut) by a bolt 78 at the tip portion. The lower arm portion 18b protrudes downward beyond the wheel hub bearing portion 11, and has a socket 62 of the ball joint 60 at the tip portion. The lower arm portion 18b changes its direction at the tip portion and extends in parallel with the axis O, and wraps directly under the wheel hub bearing portion 11. For this reason, the position of the socket 62 in the direction of the axis O overlaps the position of the fixed shaft 15 in the direction of the axis O.

The ball portion 61b is allowed to rotate in a free direction as a connection point between the in-wheel motor drive device 10 and the suspension device 70. The straight line extending in the vertical direction through the upper end of the suspension member 76 (strut) and the ball portion 61b constitutes the wheel wheel W and the steered shaft K of the in-wheel motor drive device 10.

Next, the rolling

bearings

44 and 46 that rotatably support the output shaft 41 will be described in detail.

Referring to FIG. 1 again, the rolling bearing 44 is disposed on the outer peripheral surface of the end portion of the output shaft 41 as a first output shaft bearing, and rotatably supports one end portion of the output shaft 41. Further, the rolling bearing 46 is disposed on the inner peripheral surface of the other end portion of the output shaft 41 positioned on the opposite side to the rolling bearing 44 as the second output shaft bearing, and the other end portion of the output shaft 41 is rotatable. To support. According to this embodiment, since the speed reduction part 31 supports the output shaft 41 rotatably by the rolling

bearings

44 and 46 separately from the wheel hub bearing part 11, the output shaft 41 can be stably supported. it can. Therefore, even when an external force is applied from the wheel W to the outer ring 12, the displacement of the output shaft 41 can be suppressed, and uneven wear or the like of the output gear 40 of the speed reduction unit 31 can be prevented. In particular, the output shaft 41 is stably supported by both the inner peripheral surface of the output shaft 41 and the outer peripheral surface of the output shaft 41.

A first annular step 41t is formed on the outer periphery of one end of the output shaft 41 in the axial direction adjacent to the side surface of the output gear 40 so that the diameter near the center in the axial direction has a large diameter. The first rolling bearing 44 is in contact with the first annular step 41t, and the position in the axis O direction is defined. According to this embodiment, the first rolling bearing 44 can be fixed so as not to be displaced in the direction of the axis O.

A second annular step 41u is formed on the inner periphery of the other end portion of the output shaft 41 in the axis O direction so that the diameter near the center in the axis direction becomes a small diameter. The second rolling bearing 46 is in contact with the second annular step 41u and has a position defined in the direction of the axis O. According to this embodiment, the second rolling bearing 46 can be fixed so as not to be displaced in the direction of the axis O.

Particularly, since the output gear 40 is a helical gear, the tooth contact with the intermediate gear 39 is improved, and an axial force acts on the output shaft 41. According to this embodiment, the axial force acting on the helical gear can be received by the first and second rolling

bearings

44 and 46 that are fixed so as not to be displaced in the direction of the axis O.

Further, according to the present embodiment, the second rolling bearing 46 is provided between the inner peripheral surface of the output shaft 41 and the outer peripheral surface of the fixed shaft 15, so that the output is performed by the fixed shaft 15 having a higher strength than the main body casing 43. The shaft 41 can be supported.

Further, according to the present embodiment, the outer ring 12 is disposed on one side in the axis O direction, and the output shaft 41 is disposed on the other side in the axis O direction. The outer ring 12 and the output shaft 41 are coupled to each other so that the inner peripheral surface at one end portion in the axis O direction of the output shaft 41 covers the outer peripheral surface at the other end portion in the axis O direction of the outer ring 12. A first rolling bearing 44 (first output shaft bearing) that rotationally supports the outer diameter of one end side of the output shaft 41, and a second rolling bearing 46 (first bearing) that rotatably supports the inner diameter of the other end side of the output shaft 41. The two output shaft bearings) are rotatably supported at both ends of the output shaft 41. Thereby, the 1st rolling bearing 44 can be arrange | positioned in the coupling | bond location of the outer ring | wheel 12 of the wheel hub bearing part 11, and the output shaft 41 of the deceleration part 31. FIG. Therefore, the position of the first rolling bearing 44 in the axis O direction can be overlapped with the position of the outer ring 12 in the axis O direction, and the total axial dimension of the outer ring 12 and the output shaft 41 can be shortened.

Further, according to the present embodiment, the output gear 40 is provided on the outer periphery of the other end portion of the output shaft 41 in the axis O direction, and the position of the output gear 40 in the axis O direction overlaps the position of the rolling bearing 46 in the axial direction. The dimension of the axis 41 in the axis O direction can be shortened.

Further, the rolling bearing 44 of the present embodiment is adjacent to the outer raceway surface 44f on the outer diameter side, the inner raceway surface 44g on the inner diameter side, and the plurality of rolling elements 44b that roll on the outer raceway surface 44f and the inner raceway surface 44g. It is a radial bearing including a retainer (not shown) that defines the circumferential interval between the rolling elements 44b that fit. The outer raceway surface 44f and the inner raceway surface 44g are circumferential grooves, and the cross sections of the outer raceway surface 44f and the inner raceway surface 44g are semicircular. The maximum outer diameter of the outer raceway surface 44f is smaller than the outer diameter of the tooth tip of the output gear 40. According to this embodiment, the diameter dimension of the first rolling bearing 44 is reduced, and as a result, the diameter dimension of the wheel hub bearing portion 11 can be further reduced. Therefore, the arrangement space of the wheel hub bearing portion 11 can be secured in the inner space of the wheel wheel W.

Next, a second embodiment of the present invention will be described. FIG. 4 is a developed cross-sectional view showing the in-wheel motor drive device 20 according to the second embodiment of the present invention cut and developed on a predetermined plane. About 2nd Embodiment, about the structure which is common in embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted, and a different structure is demonstrated below. In the second embodiment, an opening 43q is formed in the back surface portion 43b of the main body casing 43, and the fixed shaft 15 is inserted into the opening 43q from the outside of the main body casing 43. The base portion 15r of the fixed shaft 15, the carrier 18, and the

bolts

13c and 13b are arranged outside the main body casing 43 with the back surface portion 43b as a boundary, and the remaining portion of the fixed shaft 15 excluding the base portion 15r is inside the main body casing 43. Be placed.

A female screw hole 43u oriented in the other axial direction is formed in the other wall surface 43bn in the axial O direction of the back surface portion 43b. The bolt 13c is reverse to the first embodiment described above, and is inserted into the through hole of the projecting portion 15p from the other in the axis O direction toward the other. The head portion 13cd of the bolt 13c contacts the protruding portion 15p from the outside of the main body casing 43. The shaft portion 13ct of the bolt 13c is screwed into the female screw hole 43u. The sealing material 49 seals the annular gap between the opening 43q and the fixed shaft 15.

A bottomless female screw 15u is formed on the protruding portion 15p of the fixed shaft 15, and a bolt 13b penetrating the carrier 18 is screwed into the female screw 15u, whereby the carrier 18 is abutted against and fixed to the protruding portion 15p. Although not shown, the female screw 15u may have a bottom.

4 also includes a first rolling bearing 44 and a second rolling bearing 46, as in the first embodiment described above. Thereby, the output shaft 41 can be supported stably.

In addition, in the second embodiment, in the assembly of the in-wheel motor drive device 20, in the assembly of the in-wheel motor drive device 20, the fixed shaft 15 is inserted into the opening 43q of the main body casing 43 from the other side in the axis O direction, and the distal end portion 15e of the fixed shaft 15 is the rear portion 43b. The motor portion 21 and the root portion 15r of the fixed shaft 15 are both disposed on the other side in the axis O direction than the back surface portion 43b. Further, referring to FIG. 2, the fixed shaft 15 and the motor unit 21 indicated by a virtual line approach each other. For this reason, for the convenience of assembly, the fixed shaft 15 is designed to be thin so that the fixed shaft 15 and the motor unit 21 do not interfere with each other.

On the other hand, in the first embodiment shown in FIG. 1, in the assembly of the in-wheel motor drive device 20, the fixed shaft 15 may be inserted into the main body casing 43 from one side in the axis O direction and fixed to the back portion 43 b. The root portion 15r is disposed on one side in the axis O direction with respect to the back surface portion 43b, and the motor portion 21 is disposed on the other side in the axis O direction with respect to the back surface portion 43b. For this reason, even if the fixed shaft 15 of the first embodiment is designed to be thicker than that of the second embodiment, there is no inconvenience in assembly.

Next, a third embodiment of the present invention will be described. FIG. 5 is a developed cross-sectional view showing the in-wheel motor drive device 30 according to the third embodiment of the present invention cut and developed on a predetermined plane. In the third embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and different configurations are described below. In the third embodiment, the cylindrical portion 43 y is formed on the back surface portion 43 b of the main body casing 43.

The cylindrical portion 43y extends along the axis O, protrudes from the one wall surface 43bm in the axis O direction, passes through the intermediate gear 37, travels in one direction in the axis O, and is inserted into the center hole of the output shaft 41. The central hole of the cylindrical portion 43y becomes an opening 43q, and the fixed shaft 15 is inserted into the opening 43q from the outside of the main body casing 43.

The second rolling bearing 46 is provided in an annular gap between the outer peripheral surface of the tip end portion of the cylindrical portion 43y and the inner peripheral surface of the other end portion in the axis O direction of the output shaft 41. As a result, the cylindrical portion 43y rotatably supports the other end portion of the output shaft 41 in the axis O direction.

The third embodiment shown in FIG. 5 also has a first rolling bearing 44 and a second rolling bearing 46 as in the first embodiment described above. Thereby, the output shaft 41 can be supported stably. However, when the cylindrical portion 43y becomes thick, the diameter of the output shaft 41 increases. Or if the cylindrical part 43y becomes thin, the support rigidity of the cylindrical part 43y will become small. For this reason, the first and second embodiments described above are preferable.

Next, a fourth embodiment of the present invention will be described. FIG. 6 is a developed cross-sectional view showing the in-wheel motor drive device 50 according to the fourth embodiment of the present invention cut and developed on a predetermined plane. In the fourth embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and different configurations are described below. In the fourth embodiment, the wheel hub bearing portion 11 is configured to rotate the inner ring and fix the outer ring. This is different from the wheel hub bearing 11 for rotating the outer ring and fixing the inner ring employed in the first to third embodiments described above.

6, the wheel hub bearing portion 11 includes an inner ring 56 that is a rotating element, an outer ring 57 that is a fixed element, and a plurality of rolling elements 58 that are arranged in an annular gap between the inner and outer rings. A flange is erected on the outer peripheral surface of the outer ring 57. A through hole is formed in the outer ring flange with a gap in the circumferential direction. Each through-hole extends in parallel with the axis O, and a bolt 57b is passed from one side of the axis O direction. The shaft portion of each bolt 57 b is screwed into a female screw hole formed in the front portion 43 f of the main body casing 43. As a result, the outer ring 57 is connected and fixed to the front portion 43f. The front portion 43f is a casing wall portion that covers one end of the speed reduction portion 31 in the axis O direction. The back surface portion 43b is a casing wall portion that covers the other end of the speed reduction portion 31 in the axis O direction.

The inner ring 56 is a cylindrical body longer than the outer ring 57 and is passed through the center hole of the outer ring 57. A coupling portion 56f is formed at one end of the inner ring 56 protruding from the outer ring 57 to the outside of the in-wheel motor drive device 50 in the axis O direction. The coupling portion 56f is a flange, and constitutes a coupling portion for coupling coaxially with a brake rotor and wheels (not shown). The inner ring 56 is attached with a wheel at a coupling portion 56f and rotates integrally with the wheel.

In the annular gap between the inner ring 56 and the outer ring 57, a plurality of rows of rolling elements 58 are arranged. The rolling elements 58 are balls, for example. One outer peripheral surface of the inner ring 56 in the direction of the axis O constitutes an outer race of the rolling elements 58 in the first row. An inner raceway 56r is fitted to the outer circumference of the other end portion of the inner ring 56 in the axis O direction, and the outer circumference surface of the inner raceway 56r constitutes the inner raceway of the rolling elements 58 in the second row. A seal material 59 is further interposed in the annular gap between the inner ring 56 and the outer ring 57. The sealing material 59 seals both ends of the annular gap in the direction of the axis O to prevent entry of dust and foreign matter. The output shaft 55 of the speed reducing portion 31 is inserted into the center hole at the other end in the axis O direction of the inner ring 56 and is spline-fitted.

A supplementary explanation of the speed reduction portion 31 will be described. One end of the input shaft 32 in the axis M direction is rotatably supported by the front portion 43f of the main body casing 43 via the rolling bearing 42a, and the other end of the input shaft 32 in the axis M direction is rolled. This is the same as the first to third embodiments described above in that it is rotatably supported by the back surface portion 43b of the main body casing 43 via the bearing 42b. However, the input gear 33 is different from the first to third embodiments in that the input gear 33 is coupled to the other side of the input shaft 32 in the axis M direction and is adjacent to the rolling bearing 42b. The input gear 33 of the first to third embodiments is coupled to one side of the input shaft 32 in the axis M direction and is adjacent to the rolling bearing 42a.

As shown in FIG. 6, the intermediate gear 34 is coupled to the other side of the intermediate shaft 35 in the axis Nf direction. The intermediate gear 36 is coupled to one side of the intermediate shaft 35 in the axis Nf direction. In this respect, this embodiment is alternated with the first to third embodiments described above.

The intermediate gear 37 is coupled to one side of the intermediate shaft 38 in the axis Nl direction. The intermediate gear 39 is coupled to the other side of the intermediate shaft 38 in the direction of the axis Nl. In this respect, this embodiment is alternated with the first to third embodiments described above.

The output shaft 55 is coupled to the output gear 40 and is rotatably supported on the front portion 43f of the main body casing 43 via the rolling bearing 55a while being in the axis O direction than the output gear 40. The rolling bearing 55 a is installed between the inner peripheral surface of the circular opening formed in the front portion 43 f and the outer peripheral surface of the output shaft 55. The rolling bearing 55 a is a ball bearing, for example, and the pitch circle thereof is larger than the pitch circle of the rolling elements 58. The output shaft 55 further extends in the direction of the axis O beyond the rolling bearing 55a. One end of the output shaft 55 in the direction of the axis O is coupled to the inner ring 56.

The output shaft 55 is rotatably supported on the back surface portion 43b of the main body casing 43 via the rolling bearing 55b on the other side in the axis O direction than the output gear 40. The rolling bearing 55 b is installed between the inner peripheral surface formed on the back surface portion 43 b and the outer peripheral surface of the output shaft 55. The rolling bearing 55 b is a ball bearing, for example, and the pitch circle thereof is larger than the pitch circle of the rolling elements 58.

The output shaft 55 further extends to the other side in the axis O direction beyond the rolling bearing 55b. The other end of the output shaft 55 in the direction of the axis O extends through the back surface portion 43 b and is coupled to the oil pump 54. The oil pump 54 is attached to the outer wall surface of the back surface portion 43b and protrudes from the outer wall surface of the back surface portion 43b. The outer diameter of the oil pump 54 is smaller than the pitch circle of the rolling

bearings

55a and 55b.

According to the in-wheel motor drive device 50 of the fourth embodiment, the input shaft 32 coupled to the motor rotating shaft 22 of the motor unit 21, the input gear 33 coupled to the input shaft 32, and the output coupled to the inner ring 56 that is a rotating wheel. A shaft 55 and an output gear 40 coupled to the output shaft 55 are included, and a drive transmission path for decelerating the rotation of the input gear 33 and transmitting it to the output gear 40 is configured. A first output shaft bearing (rolling bearing 55a) that rotatably supports one end of the output shaft 55 in the axis O direction and a second output shaft bearing (rolling bearing 55b) that rotatably supports the other end of the output shaft 55 in the axis O direction. ), The both ends of the output shaft 55 are rotatably supported. As a result, the output shaft 55 can be stably supported at both ends. Therefore, even if an external force is applied from the wheel to the inner ring 56, the displacement of the output shaft 55 can be suppressed, and uneven wear of the output gear 40 of the speed reduction unit 31 can be prevented.

Further, the rolling

bearings

55 a and 55 b as the first and second output shaft bearings are supported by the main body casing 43 of the speed reduction unit 31. As a result, the output shaft 55 is stably held in the speed reduction unit 31.

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

bearings

44 and 46 described above are ball bearings, a cylindrical roller bearing or an angular bearing may be used as a modification (not shown).

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

10 in-wheel motor drive device, 11 wheel hub bearing, 12 outer ring, 12f flange, 13 inner fixing member, 13b, 13c bolt, 14 rolling element, 15 fixed shaft, 15e tip, 15n other end surface in axial direction, 15p protruding Part, 15r root part, 16 inner race, 17 retaining nut, 18 carrier, 19 intermediate member, 21 motor part, 22 motor rotating shaft, 25 motor casing, 25v motor casing cover, 31 deceleration part, 32 input shaft, 33 input Gear, 34, 36, 37, 39 intermediate gear, 35, 38 intermediate shaft, 40 output gear, 41 output shaft, 41t first annular step, 41u second annular step, 43 main body casing, 43b back portion, 43p, 43q opening , 43y cylindrical part, 44 rolling Bearing (first output shaft bearing), 44f outer raceway surface, 44b rolling element, 44g inner raceway surface, 46 rolling bearing (second output shaft bearing), 47 oil tank, 49 seal material, 51 pump shaft, 53 pump gear, 54 Oil pump, 55 output shaft, 56 inner ring, 57 outer ring, 58 rolling element, 60 ball joint, 61 ball stud, 61b ball part, 61s stud part, 62 socket, 70 suspension device, 71 suspension member, 72 outer end in the vehicle width direction 72n nut, 73 vehicle width direction inner side end, 76 suspension member, 76b lower end, 76s shock absorber, 77 upper end region, K steered axle, M, Nf, Nl, O, P axis, S space, T tire, W Wheel wheel, Wr rim, Ws spoke .

Claims

A motor unit that drives the wheel, a wheel hub bearing unit to which the wheel is attached, and a speed reduction unit that decelerates the rotation of the motor unit and transmits it to the wheel hub bearing unit,
The wheel hub bearing portion includes a rotating wheel that rotates integrally with a wheel, a fixed wheel that is disposed coaxially with the rotating wheel, and a plurality of rolling elements that are disposed in an annular gap between the rotating wheel and the fixed wheel. ,
The speed reduction unit includes an input shaft coupled to a motor rotation shaft of the motor unit, an input gear coupled to the input shaft, an output shaft coupled to the rotating wheel, and an output gear coupled to the output shaft. A drive transmission path that decelerates the rotation of the motor and transmits it to the output gear,
An in-wheel in which both ends of the output shaft are rotationally supported by a first output shaft bearing that rotationally supports one end side of the output shaft and a second output shaft bearing that rotationally supports the other end side of the output shaft. Motor drive device.
The in-wheel motor drive device according to claim 1, wherein the rotating wheel is an outer ring, and the fixed wheel is included in a fixed shaft that is passed through a center hole of the outer ring.
The first output shaft bearing rotatably supports the outer diameter of one end side of the output shaft;
The in-wheel motor drive device according to claim 1, wherein the second output shaft bearing rotatably supports an inner diameter on the other end side of the output shaft.
A first annular step is formed on the outer periphery of the one end portion of the output shaft so that the axial center side has a large diameter,
The in-wheel motor drive device according to claim 3, wherein the first output shaft bearing has an axial position defined by the first annular step.
A second annular step is formed on the inner periphery of the other end portion of the output shaft so that the center in the axial direction has a small diameter,
5. The in-wheel motor drive device according to claim 3, wherein the second output shaft bearing has an axial position defined by the second annular step. 6.
The in-wheel motor drive device according to claim 4 or 5, wherein the output gear is a helical gear.
The in-wheel motor drive device according to claim 3, wherein the second output shaft bearing is provided between an inner peripheral surface of the output shaft and an outer peripheral surface of the fixed shaft.
The outer ring is disposed on one side in the axial direction of the wheel hub bearing portion, the output shaft is disposed on the other side in the axial direction of the wheel hub bearing portion, and an inner peripheral surface of one end portion of the output shaft is in the axial direction of the outer ring. The outer ring and the output shaft are coupled to each other so as to cover the outer peripheral surface of the other end,
The first output shaft bearing rotatably supports an outer peripheral surface of one end portion of the output shaft,
The in-wheel motor drive device according to claim 7, wherein the second output shaft bearing rotatably supports an inner peripheral surface of the other end portion of the output shaft.
The output gear is provided on the outer periphery of the other end of the output shaft,
The in-wheel motor drive device according to claim 8, wherein an axial position of the output gear overlaps with an axial position of the second output shaft bearing.
The first output shaft bearing is a radial bearing including an outer raceway surface on the outer diameter side, an inner raceway surface on the inner diameter side, and a plurality of rolling elements rolling on the outer raceway surface and the inner raceway surface,
The in-wheel motor drive device according to claim 8 or 9, wherein a maximum outer diameter of the outer raceway surface is smaller than an outer diameter of the output gear.
2. The in-wheel motor drive device according to claim 1, wherein the fixed wheel is an outer ring, and the rotating wheel is an inner ring disposed in a center hole of the outer ring.
The in-wheel motor drive device according to claim 11, wherein the first output shaft bearing and the second output shaft bearing are supported by a casing of the speed reduction unit.