JP7182890B2 - Connection structure of in-wheel motor drive device and suspension device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-wheel motor drive device that is arranged inside a wheel to drive the wheel, and a suspension device that connects the in-wheel motor drive device to a vehicle body.

Conventionally, as a connection structure between an in-wheel motor and a suspension, for example, those described in Japanese Patent Application Laid-Open No. 2017-165279 (Patent Document 1) and Patent Application Publication Specification CN106926656A of the People's Republic of China (Patent Document 2) are known. there is The connection structure described in Patent Document 1 and Patent Document 2 includes a carrier attached and fixed to an in-wheel motor and extending in the vertical direction, a lower arm arranged below the in-wheel motor, and a ball connecting the lower arm to the carrier. a joint;

A ball joint has a ball and socket that are slidably connected and a stud that engages the ball. The stud is fixed to the outer end of the lower arm in the vehicle width direction. A socket is fixed to the lower end of the carrier. A fixing structure of the socket is described in Patent Document 2.

FIG. 8 is a perspective view showing a connected state of a conventional in-wheel motor 7 and a lower arm 6 described in Patent Document 2. As shown in FIG. A carrier 2 is fixed to the casing of the in-wheel motor 7 . FIG. 9 is an enlarged cross-sectional view showing a conventional socket fixing structure described in Patent Document 2, which corresponds to the portion surrounded by a dashed line in FIG. 8 . As shown in FIG. 9, the ball stud 5 of the ball joint is fixed to the outer end of the lower arm 6 in the vehicle width direction with the ball facing upward and the stud facing downward.

A ball joint socket is fixed to the lower end of the carrier 2 with three bolts 8 . Two of the three bolts 8 are represented in FIG. One bolt 8 is enlarged in FIG. Each bolt 8 has a shank extending upward with its head downward, and the shank is screwed into an internal thread formed in the carrier 2 .

JP 2017-165279 A People's Republic of China Patent Application Publication CN106926656A Paragraph 0015

However, the above-described conventional fixing structure causes problems as described below.
That is, the head of the bolt is positioned at the same height as the ball, and the shaft of the bolt extends above the head. Therefore, it is necessary to secure a space of the vertical dimension Le from the center of the ball to the upper end of the bolt below the in-wheel motor 7 . Since the inner hollow area of the wheel in which the in-wheel motor 7 is arranged is narrow, if the space of the dimension Le is occupied by the conventional fixing structure, the in-wheel motor 7 must be installed in the remaining space. In addition, the in-wheel motor is greatly restricted such that the in-wheel motor having the necessary dimensions cannot be arranged in the inner hollow area of the wheel. Therefore, space saving of the fixed structure is desired.

Further, in the above-described conventional fixing structure, as shown in FIG. 8, the distance Lf from the axis O representing the axle to the center of the ball becomes large, resulting in deterioration of the suspension characteristics.

In the conventional fixing structure, as shown in FIG. 9, a screw hole is formed in the carrier 2 by tapping and a bolt 8 is screwed therein. Therefore, when the carrier 2 is made of aluminum casting for the purpose of weight reduction, there is a possibility that the strength of the screw thread of the carrier 2 cannot be sufficiently secured. The reason for this is that there is concern that the screw thread may be damaged due to blowholes contained in the carrier 2 and that the screw thread may be damaged over time due to repeated attachment and detachment of the bolt 8 during vehicle maintenance. Therefore, it is desired to improve the strength and durability of the fixing structure.

On the other hand, if the missing threads are compensated for by the number of threads, the length of the threaded hole in the carrier 2 becomes longer, and the vertical dimension Le from the center of the ball to the upper end of the bolt becomes larger. Then, as described above, the diameter of the in-wheel motor is further reduced, the output is reduced, and the suspension characteristics are further deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a connection structure between an in-wheel motor and a suspension that can save space and improve suspension characteristics, strength, and durability.

For this purpose, the connection structure for an in-wheel motor drive device and a suspension device according to the present invention includes a bracket provided in the in-wheel motor drive device, a suspension member displaceably connected to a vehicle body member, and a bracket attached to the suspension member. and a connecting ball joint. Such a ball joint has a vertically extending stud, a ball provided at the end of the stud, and a socket enclosing the ball. The bracket provided in the in-wheel motor drive device has an upper opening, a lower opening, an internal space connecting the upper opening and the lower opening and holding the outer surface of the socket, a slit connecting to the internal space, and a slit. It has locking means for retracting to secure the socket to the bracket. A stud protrudes from one of the upper opening and the lower opening, and the remaining other faces the casing surface of the in-wheel motor drive device.

According to the connecting structure of the present invention, it is no longer necessary to provide the bracket with a vertically extending screw hole as in the conventional art. Therefore, the vertical dimension of the bracket can be made smaller than before, and space saving of the connecting structure can be achieved. Also, the strength and durability of the connecting portion are improved. Also, the output can be increased by increasing the diameter of the in-wheel motor drive device. Alternatively, the suspension characteristics can be improved by bringing the center of the ball closer to the axle.

The structure of the fixing means is not particularly limited. As one aspect of the present invention, the fixing means includes through holes formed in a pair of bracket portions facing each other through a slit of the bracket and extending across the slit, and a pair of head portions through which the shaft portion is passed through the through hole. and a female threaded portion provided on the other of the pair of bracket portions and screwed with the shaft portion of the bolt. According to this aspect, since the bolt head and the female threaded portion are provided on one and the other of the pair of bracket portions that face each other in the horizontal direction through the slit, the vertical dimension of the bracket can be made smaller than before. . The female threaded portion is, for example, a nut, and the nut is locked to the other of the pair of bracket portions.

The arrangement of the through holes is not particularly limited. As a preferred aspect of the present invention, the through hole extends through the joint between the interior space of the bracket and the slit, the outer surface of the socket is formed with a recess, and the shank of the bolt engages with the recess of the socket. According to this aspect, it is possible to prevent the socket from slipping out of the upper opening and the lower opening of the internal space.

The suspension member is not particularly limited as long as it is a movable member that connects an unsprung member (wheel-side member) and a sprung member (vehicle-side member) when viewed from the suspension device. As a further preferred aspect of the present invention, the suspension member is a lower arm arranged below the in-wheel motor drive device and capable of swinging vertically. According to this aspect, the suspension characteristics are improved in the suspension device in which the center of the ball defines the steering axis. As another aspect, the suspension member is an upper arm arranged above the in-wheel motor drive device and capable of swinging in the vertical direction.

The material of the bracket is not particularly limited. In one aspect of the invention, the bracket is an aluminum-based casting. According to this aspect, it is possible to reduce the weight and cost of the bracket. As another aspect, the bracket may be made of metal other than aluminum, or may be forged.

As described above, according to the present invention, the connection structure between the in-wheel motor drive device and the suspension device can be made more space-saving than before, and the outer diameter of the in-wheel motor drive device can be increased. By bringing them closer together, the suspension characteristics can be improved. Also, the strength and durability of the connecting structure are improved. Also, the weight and cost of the bracket can be reduced.

It is an expansion sectional view showing an in-wheel motor drive. 1 is a schematic diagram showing a connection structure between an in-wheel motor drive device and a suspension device according to an embodiment of the present invention; FIG. It is a schematic diagram which shows the suspension bracket of an in-wheel motor drive device. 1 is a schematic diagram showing a connection structure between an in-wheel motor drive device and a suspension device according to an embodiment of the present invention; FIG. It is a longitudinal cross-sectional view which shows the connection structure of the same embodiment. It is a cross-sectional view which shows the connection structure of the same embodiment. It is a schematic diagram which shows the connection structure of a comparative in-wheel motor drive device and a suspension apparatus. FIG. 10 is a perspective view showing a conventional connected state of an in-wheel motor and a lower arm; FIG. 9 is an enlarged sectional view showing the socket fixing structure of FIG. 8;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a developed sectional view showing an in-wheel motor drive device. FIG. 2 is a schematic diagram showing a connection structure between an in-wheel motor drive device and a suspension device according to an embodiment of the present invention, and shows the inside of the in-wheel motor drive device with a phantom line when viewed in the axle direction. As shown in FIG. 1, the in-wheel motor drive device 10 includes a wheel hub bearing portion 11 provided at the center of the wheel, a motor portion 21 that drives the wheel, and a wheel hub bearing portion that decelerates the rotation of the motor portion 21. 11 and a deceleration unit 31 that transmits the speed reduction unit 31 . The motor portion 21 and the reduction portion 31 are arranged offset from the axis O of the wheel hub bearing portion 11 . The axis O extends in the vehicle width direction and coincides with the axle. Regarding the position in the direction of the axis O, the wheel hub bearing portion 11 is arranged on one side (outboard side) of the in-wheel motor drive device 10 in the axial direction, and the motor portion 21 is arranged on the other side (inboard side) of the in-wheel motor drive device 10 in the axial direction. , the speed reduction section 31 is arranged on one side of the motor section 21 in the axial direction, and the axial position of the speed reduction section 31 overlaps the axial position of the wheel hub bearing section 11 .

The wheel is a wheel W shown in FIG. 2 with a tire (not shown) mounted on the outer periphery thereof. The in-wheel motor drive device 10 is arranged in the inner hollow region of the wheel W. As shown in FIG. The wheel hub bearing portion 11 and the deceleration portion 31 are accommodated in the inner hollow region of the wheel W. As shown in FIG. The motor portion 21 protrudes from the inner hollow region of the wheel W in the other axial direction (inboard side).

The wheel hub bearing portion 11 is a rotating inner ring/fixed outer ring, and includes an inner ring 12 as a rotating ring (hub ring) coupled to the wheel W, and an outer ring as a fixed ring coaxially arranged on the outer diameter side of the inner ring 12. 13 and a plurality of rolling elements 14 arranged in the annular space between the inner ring 12 and the outer ring 13 .

The outer ring 13 is attached and fixed to the front portion 39f of the body casing 39 of the reduction section 31 by means of coupling means such as bolts. The front portion 39f is a casing wall portion that covers one end of the reduction section 31 in the direction of the axis O in the main casing 39. As shown in FIG.

The motor section 21 has a motor rotating shaft 22, a rotor 23, a stator 24, and a motor casing 29, which are arranged in this order from the axis M of the motor section 21 to the outer diameter side. The motor unit 21 is an inner rotor/outer stator type radial gap motor, but may be an electric motor of another type. For example, although not shown, the motor section 21 may be an axial gap motor. A motor casing 29 surrounds the outer circumference of the stator 24 . One end of the motor casing 29 in the direction of the axis M is coupled to the back surface portion 39b of the body casing 39 of the deceleration section 31 . The other end of the motor casing 29 in the direction of the axis M is sealed with a plate-shaped motor casing cover 29v. The rear surface portion 39b is a casing wall portion that covers the other end of the speed reduction portion 31 in the direction of the axis O in the main body casing 39 .

The main body casing 39, the motor casing 29, and the motor casing cover 29v form a casing forming the outer shell of the in-wheel motor drive device 10, and are also simply referred to as a casing. This casing is made of aluminum or an aluminum alloy.

Both ends of the motor rotating shaft 22 are rotatably supported by the rear portion 39b of the main body casing 39 and the motor casing cover 29v of the motor section 21 via rolling bearings 27 and 28, respectively.

An axis M around which the motor rotating shaft 22 and the rotor 23 rotate extends parallel to the axis O of the wheel hub bearing portion 11 . That is, the motor portion 21 is offset away from the axis O of the wheel hub bearing portion 11 . For example, as shown in FIG. 2, the axis M of the motor section is offset from the axis O in the longitudinal direction of the vehicle, and more specifically, is arranged in front of the axis O of the vehicle.

As shown in FIG. 1, the speed reduction unit 31 includes an input shaft 32 coaxially coupled to the motor rotation shaft 22 of the motor unit 21, an input gear 33 coaxially provided on the outer peripheral surface of the input shaft 32, and a plurality of intermediate gears 34. , 36, an intermediate shaft 35 coupled to the centers of these intermediate gears 34, 36, an output shaft 38 coupled to the inner ring 12 of the wheel hub bearing portion 11, and an output gear coaxially provided on the outer peripheral surface of the output shaft 38. 37 and a body casing 39 that accommodates these multiple gears and rotating shafts. The main body casing 39 forms an outer shell of the reduction section 31 and is therefore also referred to as a reduction section casing.

The input gear 33 is an external helical gear. The input shaft 32 has a hollow structure, and one axial end 22e of the motor rotating shaft 22 is inserted into a hollow hole 32h of the input shaft 32 and spline-fitted (including serrations, the same shall apply hereinafter) so as not to rotate relative to each other. The input shaft 32 is rotatably supported on both end sides of the input gear 33 by a front portion 39f and a rear portion 39b of the body casing 39 via rolling bearings 32a and 32b.

An axis N, which is the center of rotation of the intermediate shaft 35 of the reduction section 31, extends parallel to the axis O. As shown in FIG. Both ends of the intermediate shaft 35 are rotatably supported by a front portion 39f and a rear portion 39b of the body casing 39 via rolling bearings 35a and 35b. A first intermediate gear 34 is coaxially provided at the other end of the intermediate shaft 35 in the direction of the axis N. As shown in FIG. A second intermediate gear 36 is coaxially provided in the central region of the intermediate shaft 35 in the direction of the axis N. As shown in FIG.

The first intermediate gear 34 and the second intermediate gear 36 are helical gears with external teeth, and the diameter of the first intermediate gear 34 is larger than the diameter of the second intermediate gear 36 . The large-diameter first intermediate gear 34 is arranged on the other side of the second intermediate gear 36 in the direction of the axis N and meshes with the small-diameter input gear 33 . The small-diameter second intermediate gear 36 is arranged on one side of the first intermediate gear 34 in the direction of the axis N and meshes with the large-diameter output gear 37 .

The axis N of the intermediate shaft 35 is arranged above the axes O and M, as shown in FIG. Further, the axis N of the intermediate shaft 35 is disposed forward of the vehicle from the axis O and rearward of the axis M from the vehicle. The speed reduction unit 31 is a three-axis parallel shaft gear speed reducer having axes O, N, and M that are spaced apart in the vehicle front-rear direction and extend parallel to each other, and is speeded down in two stages. As a modified example (not shown), the speed reducer 31 may be a multistage parallel shaft gear speed reducer having a plurality of intermediate shafts.

Returning to FIG. 1, the output gear 37 is a helical gear with external teeth, and is provided coaxially with the central portion of the axis O of the output shaft 38 . The output shaft 38 extends along the axis O. As shown in FIG. One end of the output shaft 38 in the direction of the axis O is inserted into the center hole of the inner ring 12 and fitted so as not to rotate relative to each other. A central portion of the output shaft 38 in the direction of the axis O is rotatably supported by a front portion 39f of the main body casing 39 via a rolling bearing 38a on the outer diameter side of the other end of the inner ring 12 in the direction of the axis O. The other end of the output shaft 38 in the direction of the axis O is rotatably supported by the back portion 39b of the main body casing 39 via a rolling bearing 38b.

As shown in FIG. 1, the speed reduction unit 31 includes a drive gear with a small diameter and a driven gear with a large diameter, that is, an input gear 33 and a first intermediate gear 34, and a second intermediate gear 36 and an output gear 37. , the rotation of the input shaft 32 is decelerated and transmitted to the output shaft 38 . A rotating element from the input shaft 32 to the output shaft 38 of the reduction section 31 constitutes a drive transmission path that transmits the rotation of the motor section 21 to the inner ring 12 of the wheel hub bearing section 11 .

The body casing 39 includes a tubular portion in addition to the front portion 39f and the rear portion 39b described above. The tubular portion covers the internal parts of the reduction section 31 so as to surround the axes O, N, M extending parallel to each other. The plate-like front portion 39f covers the internal parts of the reduction section 31 from one side in the axial direction and is coupled to one end of the cylindrical portion. The plate-like back surface portion 39b covers the internal parts of the speed reducing portion 31 from the other side in the axial direction and is coupled to the other end of the tubular portion. A rear portion 39 b of the body casing 39 is coupled to the motor casing 29 and also serves as a partition separating the interior space of the reduction section 31 and the interior space of the motor section 21 . The motor casing 29 is supported by the body casing 39 and protrudes from the body casing 39 to the other side in the axial direction.

The body casing 39 partitions the internal space of the reduction section 31 and accommodates all the rotating elements (rotating shaft and gears) of the reduction section 31 in the internal space. As shown in FIG. 2, the lower portion of the main body casing 39 serves as an oil reservoir 39t. The height position of the oil storage portion 39 t overlaps the height position of the lower portion of the motor portion 21 . Lubricating oil for lubricating the motor portion 21 and the reduction portion 31 is stored in an oil reservoir portion 39t that occupies the lower portion of the internal space of the main body casing 39 .

The input shaft 32, the intermediate shaft 35, and the output shaft 38 are both supported by the rolling bearings described above. These rolling bearings 32a, 35a, 38a, 32b, 35b, 38b are radial bearings.

When electric power is supplied to the motor portion 21 from the outside of the in-wheel motor drive device 10 , the rotor 23 of the motor portion 21 rotates, and rotation is output from the motor rotation shaft 22 to the reduction portion 31 . The deceleration unit 31 decelerates the rotation input from the motor unit 21 to the input shaft 32 and outputs it from the output shaft 38 to the wheel hub bearing unit 11 . The inner ring 12 of the wheel hub bearing portion 11 rotates at the same rotational speed as the output shaft 38 to drive the wheel W attached and fixed to the inner ring 12 .

FIG. 3 is a schematic diagram showing a suspension bracket that attaches the in-wheel motor drive device to the suspension device, and represents a state seen in the vehicle front-rear direction. A suspension bracket 17 is fixed to the outer wall surface of the main body casing 39 . With reference to FIG. 2, the suspension bracket 17 is offset to the side opposite to the motor portion 21, specifically, to the rear of the vehicle in the vehicle front-rear direction.

As shown in FIG. 3, the suspension bracket 17 extends vertically. The upper end portion 17b of the suspension bracket 17 is arranged inward in the vehicle width direction from the deceleration portion 31 and protrudes from the inner hollow region of the wheel W. As shown in FIG. Further, the upper end portion 17b is arranged behind the motor portion 21 in the vehicle. Also, the upper end portion 17 b is arranged above the in-wheel motor drive device 10 , but is positioned lower than the upper portion of the deceleration portion 31 . The upper end portion 17b is fixed to the lower end portion of the strut 41 by fixing means such as bolts 18 or the like.

Suspension bracket 17 is preferably made of aluminum or other light metal to reduce unsprung loads on the suspension system. Suspension bracket 17 may also be an aluminum casting.

The strut 41 is a suspension member that extends in the vertical direction, and is specifically a shock absorber that combines damping means such as a damper and elastic means such as a coil spring. When the in-wheel motor drive device 10 attached under the spring as viewed from the suspension member bounces and rebounds in the vertical direction, the strut 41 expands and contracts in the vertical direction to attenuate the bounce and rebound of the in-wheel motor drive device 10 .

A tie-rod arm 19 is provided at the vertical central portion 17c of the suspension bracket 17 . The tie rod arm 19 protrudes from the suspension bracket 17 in the longitudinal direction of the vehicle. The tip of the tie rod arm 19 is connected to a tie rod of a steering system (not shown).

A lower end portion 17d of the suspension bracket 17 is arranged below the deceleration portion 31 and accommodated in the inner hollow region of the wheel W. As shown in FIG. Referring to FIG. 2, the lower end portion 17d forms a vertical gap G with the main body casing 39. As shown in FIG. The height position of the lower end portion 17d overlaps the height position of the oil reservoir 39t. The lower end portion 17 d is connected to the lower arm 42 via a ball joint 51 . A straight line connecting the center of the ball 53 of the ball joint 51 and the upper end of the strut 41 constitutes a turning axis K. As shown in FIG. The in-wheel motor drive device 10 can be steered around the steering axis K together with the wheels W. As shown in FIG. The center of the ball 53 is also called a hard point.

The lower arm 42 is a suspension member that extends in the vehicle width direction below the in-wheel motor drive device 10 and the suspension bracket 17 and has vehicle width direction inner ends 43 and 44 and a vehicle width direction outer end 45 . The vehicle width direction inner ends 43 and 44 are connected to a vehicle body side member (not shown) via a pivot shaft. The vehicle width direction outer end 45 is arranged directly below the lower end portion 17 d and coupled with the stud 52 of the ball joint 51 . 2, the lower arm 42 is shown in a simplified diagrammatic form.

The lower arm 42 can swing vertically with the vehicle width direction inner ends 43 and 44 as base ends and the vehicle width direction outer end 45 as a free end. As a result, the in-wheel motor drive device 10 attached under the spring when viewed from the suspension member can bounce and rebound in the vertical direction.

The lower arm 42 and strut 41 constitute a suspension device. This embodiment is a strut-type suspension device. The vehicle body side member means a member attached to the vehicle body side when viewed from the member to be described.

Next, the connection structure between the suspension bracket 17 and the lower arm 42 will be described in detail.

FIG. 4 is a schematic diagram showing a connection structure between an in-wheel motor drive device and a suspension device according to an embodiment of the present invention, and is an enlarged view of the vicinity of the ball joint 51 in FIG. FIG. 5 is a vertical cross-sectional view showing the connection structure of the same embodiment, and is an enlarged view of the ball joint 51 and its surroundings shown in FIG. FIG. 6 is a cross-sectional view showing the connecting structure of the same embodiment, and represents a cross section of the same embodiment taken along the AA plane shown in FIGS. 4 and 5. FIG. The ball joint 51 has a vertically extending stud 52 , a ball 53 provided at the end of the stud 52 , and a socket 54 connected to the ball 53 .

The stud 52 of this embodiment extends vertically and connects with the ball 53 at its upper end. Since the stud 52 and the ball 53 are one member, they are also called a ball stud. A lower end portion of the stud 52 is passed through a vertically extending through hole formed in the vehicle width direction outer end 45 of the lower arm 42 and protrudes downward from the vehicle width direction outer end 45 . A male thread is formed on the outer circumference of the protruding portion and is screwed with the nut 55 . The stud 52 is fixed to the outer end 45 in the vehicle width direction by fixing means such as a nut 55 . A washer 61 may be interposed between the nut 55 and the lower surface of the lower end portion 17d.

The socket 54 has a spherical recess 54q that encloses the ball 53 at its center. The spherical recess 54q has an opening on the lower surface of the socket 54. As shown in FIG. The inner diameter of the opening of the spherical recess 54 q is smaller than the outer diameter of the ball 53 . Therefore, the ball 53 does not escape from the spherical recess 54q. The stud 52 protrudes downward from the opening of the spherical recess 54q. The ball 53 is slidable within the socket 54, and the attitude of the stud 52 as viewed from the socket 54 is steplessly changed in universal directions.

A lower end portion 17 d of the suspension bracket 17 defines an internal space 56 . The internal space 56 is a round hole extending vertically through the lower end portion 17d. Therefore, the internal space 56 is a space that includes an upper opening 56b and a lower opening 56c and connects the upper opening 56b and the lower opening 56c. Interior space 56 accommodates socket 54 . The inner surface of the lower end portion 17 d that defines the internal space 56 contacts the outer surface of the socket 54 . Such contact may be a loose fit or a press fit. As shown in FIG. 6, the inner surface of the interior space 56 and the outer surface of the socket 54 are of circular cross-section. 4 and 5, the inner surface of the internal space 56 is a cylindrical surface. As a modification not shown, the inner surface of the internal space 56 may be conical. Stud 52 protrudes from lower opening 56c. The upper opening 56b faces the surface of the main body casing 39 below the in-wheel motor drive device 10 (Fig. 2).

The socket 54 accommodated in the upper surface of the lower end portion 17d and the internal space 56 faces the lower surface of the in-wheel motor drive device 10 via the vertical gap G as shown in FIG. The lower surface is specifically the surface of the body casing 39 . Thereby, the clearance of the vertical gap G is secured between the lower end portion 17d and the main body casing 39. As shown in FIG.

A protrusion 54p is formed at the bottom of the socket 54 . The protrusion 54p is, for example, a small flange and is formed flush with the lower surface of the socket 54. As shown in FIG. The protrusion 54p contacts the lower surface of the lower end portion 17d. As a result, the socket 54 is restricted from the internal space 56 coming out upward.

The lower end portion 17d and the vehicle width direction outer end 45 are arranged with a space therebetween in the vertical direction, and a stud 52 is provided therebetween. The stud 52 is surrounded by a bellows-shaped rubber boot 57 between the lower end portion 17d and the outer end 45 in the vehicle width direction. One end of rubber boot 57 connects with the lower surface of socket 54 and seals ball 53 . The other end of the rubber boot 57 is connected to the vehicle width direction outer end 45 to seal the stud 52 . Ball 53 and stud 52 are thereby protected from external foreign matter.

As shown in FIG. 6, a slit 58 is formed in the lower end portion 17d. The slit 58 is a gap opened in the horizontal direction (vehicle front-rear direction) connecting the outer surface 17f of the lower end portion 17d and the internal space 56 . The lower end portion 17d includes a pair of bracket portions 17g and 17j facing each other through the slit 58. As shown in FIG.

Through holes 17h are formed in the pair of bracket portions 17g and 17j. The through hole 17h is a through hole extending straight in the horizontal direction (vehicle front-rear direction) from one bracket portion 17g to the other bracket portion 17j, and intersects the slit 58. As shown in FIG. 17 h of through-holes are arrange|positioned in the up-down direction center area|region of the lower end part 17d. A bolt 59 is passed through the through hole 17h.

A bolt 59 extends across the slit 58 . The head of the bolt 59 is engaged with the outer surface of one bracket portion 17g. A shaft portion of the bolt 59 protrudes from the outer surface of the other bracket portion 17j. A nut 60 is screwed onto the tip of the bolt 59 projecting from the other bracket portion 17j.

Through hole 17 h , bolt 59 and nut 60 constitute fixing means for fixing socket 54 to suspension bracket 17 . When the bolt 59 and nut 60 are tightened, the slit 58 contracts, and the inner surface of the lower end portion 17d defining the internal space 56 binds the outer surface of the socket 54 tightly. The socket 54 is thereby fixed to the lower end portion 17d.

The through hole 17h extends through the connecting portion between the slit 58 and the internal space 56 . Therefore, the through hole 17h connects with both the slit 58 and the internal space 56 . As a modified example (not shown), the through hole 17h may be a through hole that connects only to the slit 58 .

A circumferential groove 54g extending over the entire circumference is formed in the outer surface of the socket 54 . The circumferential groove 54g has a semicircular cross section, and the shaft portion of the bolt 59 engages with the circumferential groove 54g. As a modified example (not shown), the circumferential groove 54g may be a recess formed only in a part of the socket 54 in the circumferential direction.

With reference to FIG. 2, according to the present embodiment, the stud 52 extends away from the axis O (axle) of the in-wheel motor drive device 10 and the ball 53 extends vertically so that the ball 53 approaches the axis O. to place. A socket 54 enclosing the ball 53 is fixed to the suspension bracket 17 of the in-wheel motor drive device 10, and a stud 52 is fixed to the lower arm 42 of the suspension device. Further, the suspension bracket 17 and the socket 54 are fixed by narrowing the slit 58 in the horizontal direction and tightening the socket 54 . As a result, the vertical dimension of the socket 54 is enough for the means for fixing the suspension bracket 17 and the socket 54 , and it does not protrude from the ball 53 in the vertical direction. Therefore, the center of the ball 53 can be brought closer to the axis O.

2, the dimension Lr from the axis O of this embodiment to the lower surface of the main body casing 39, the gap width Lg of the vertical gap G, the dimension Ld from the upper surface of the lower end portion 17d to the center of the ball 53, and the axis O to the center of the ball 53 is represented by Equation 1 below.

[Formula 1]
Lr + Lg + Ld = Lb

FIG. 7 is a schematic diagram showing the connection structure of the in-wheel motor drive device and the suspension device in comparison, and shows the state seen in the axle direction, as in FIG. 2 . For comparison, the same reference numerals are given to the configurations common to the above-described embodiment, and the description thereof is omitted, and the different configurations are described below.

In contrast to FIG. 7, instead of the slit 58 described above, the socket 54 is formed with a flange 54f. The flange 54f is an annular plate having a vertical thickness. The flange 54f is provided with holes penetrating in the plate thickness direction at intervals in the circumferential direction. A plurality of upwardly extending screw holes 17n are formed in the lower surface of the lower end portion 17d. The arrangement of the screw holes 17n corresponds to the through holes of the flange 54f. A bolt 54b passes through the through hole of the flange 54f and is screwed into the screw hole 17n. The socket 54 is thereby fixed to the lower end portion 17d.

The vertical dimension of the lower end portion 17d is greater than the length of the screw hole 17n. The socket 54 protrudes downward from the lower end 17d. A bolt head of the bolt 54b protrudes downward from the flange 54f.

In the comparison of FIG. 7, the dimension Lr from the axis O to the lower surface of the main body casing 39, the clearance width Lg of the vertical clearance G, the dimension Le from the upper surface of the lower end portion 17d to the center of the ball 53, and from the axis O A distance Lf to the center of the ball 53 is expressed by Equation 2 below.

[Formula 2]
Lr + Lg + Le = Lf

The dimension Le from the upper surface of the lower end portion 17d to the center of the ball 53 is equal to the vertical dimension from the upper surface to the lower surface of the lower end portion 17d when the tip of the bolt 54b does not protrude from the upper surface of the lower end portion 17d, and the plate thickness of the flange 54f. It is the sum of the dimension and the distance from the lower surface of the flange 54f to the center of the ball 53. Alternatively, when the tip of the bolt 54b protrudes from the upper surface of the lower end portion 17d, the dimension Le is the vertical dimension from the tip of the bolt 54b to the lower surface of the lower end portion 17d, the thickness dimension of the flange 54f, and the lower surface of the flange 54f. It is the sum of the distances to the center of the ball 53 . The distance from the lower surface of the flange 54f to the center of the ball 53 is greater than or equal to the length of the head of the bolt 54b. That is, the dimension Le is equal to or greater than the full length of the bolt 54b.

Comparing Equation 1 and Equation 2, Lb<Lf holds. This is because Ld<Le. Ld is equal to or smaller than the vertical dimension from the upper surface to the lower surface of the lower end portion 17d.

The connection structure between the in-wheel motor drive device and the suspension device of the present embodiment includes a suspension bracket 17 provided in the in-wheel motor drive device 10 and a lower arm 42 displaceably connected to the vehicle body side member as shown in FIG. , a ball joint 51 connecting the suspension bracket 17 to the lower arm 42 . As shown in FIG. 4, the ball joint 51 has a vertically extending stud 52, a ball 53 provided at the end of the stud 52, and a socket 54 connected to the ball 53 with a spherical recess 54q surrounding the ball 53. As shown in FIG. The lower end portion 17d of the suspension bracket 17 has an upper opening 56b, a lower opening 56c, an internal space connecting the upper opening 56b and the lower opening 56c and holding the outer surface of the socket 54, and a slit 58 connecting with this internal space. ( FIG. 6 ), and bolts 59 and nuts 60 that close slits 58 to secure socket 54 to suspension bracket 17 . The stud 52 protrudes from the lower opening 56c, and the upper opening 56b faces the surface of the body casing 39 of the in-wheel motor drive device 10. As shown in FIG. The socket 54 does not protrude from the upper opening 56b. Therefore, the vertical gap G can ensure a clearance of dimension Lg.

As a result, referring to FIG. 2, the dimension Ld from the upper surface of the lower end portion 17d to the center of the ball 53 can be reduced, and the space of the connecting structure can be reduced. Further, unlike the conventional fixing means, it is not necessary to tap the lower end portion 17d to form a screw thread, and the suspension bracket 17 can be made of cast aluminum to reduce the cost and weight. Also, the diameter of the output shaft gear 37 can be increased to increase the torque of the wheels. Alternatively, the suspension characteristics can be improved by reducing the distance Lb from the axis O to the center of the ball 53 .

The fixing means for fixing the socket 54 of the present embodiment to the lower end portion 17d includes a through hole 17h extending across the slit 58, a shaft portion passed through the through hole 17h, and a head portion engaged with one bracket portion 17g. and a nut 60 positioned adjacent to the other bracket portion 17j and screwed onto the shank of the bolt 59. This eliminates the need to arrange the head of the bolt 59 and the nut 60 on the upper surface of the lower end portion 17d, and the vertical gap G can be secured.

In addition, the through hole 17h of this embodiment extends through the connecting portion of the internal space 56 and the slit 58, the outer surface of the socket 54 is formed with a circumferential groove 54g, and the shaft portion of the bolt 59 engages with the circumferential groove 54g. do. This prevents the socket 54 from slipping out of the internal space 56 .

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiment within the same scope as the present invention or within an equivalent scope. For example, a part of configuration may be extracted from one embodiment described above, another part of configuration may be extracted from another embodiment described above, and these extracted configurations may be combined.

INDUSTRIAL APPLICABILITY The present invention is advantageously used in electric vehicles and hybrid vehicles.

10 in-wheel motor driving device, 11 wheel hub bearing,
17 suspension bracket, 17b upper end, 17c vertical center,
17d lower end, 17f outer surface, 17g, 17j bracket portion,
17h through hole (fixing means), 21 motor section, 24 stator,
29 motor casing, 39 body casing,
41 strut, 42 lower arm, 51 ball joint,
52 stud, 53 ball, 54 socket,
56 internal space, 58 slit, 59 bolt (fixing means),
60 nut (fixing means), K steering axis, O axis (axle),
W wheel Wheel (wheel).

Claims (5)

a bracket, which is a member fixed to a casing that forms the outer shell of the in-wheel motor drive device, and includes a connecting portion that is arranged with a vertical gap from the surface of the casing in the inner hollow region of the wheel;
a suspension member displaceably connected to the vehicle body side member;
a ball joint that connects the connecting portion of the bracket to the suspension member;
The ball joint has a vertically extending stud, a ball provided at the end of the stud, and a socket enclosing the ball,
The connecting portion of the bracket has an upper opening, a lower opening, an internal space connecting the upper opening and the lower opening and holding the outer surface of the socket, and communicates with the internal space and penetrates in the vertical direction. and fixing means for contracting the slit to fix the socket to the bracket;
A connecting structure for an in-wheel motor drive device and a suspension device, wherein the stud protrudes from one of the upper opening and the lower opening, and the remaining other faces the surface of the casing. The fixing means includes a through hole formed in a pair of bracket portions facing each other through the slit and extending across the slit, and a shaft portion passing through the through hole and a head portion of the pair of bracket portions. 2. The in-wheel motor drive device and suspension device according to claim 1, further comprising: a bolt that is locked to one of said pair of bracket portions, and a female thread portion that is provided on the other of said pair of bracket portions and screwed with said bolt shaft portion. connected structure. the through hole extends through a connection point between the internal space and the slit,
A concave portion is formed on the outer surface of the socket,
3. The connecting structure for an in-wheel motor drive device and a suspension device according to claim 2, wherein the shaft portion of said bolt engages with said recess. The connecting portion is a lower end,
The connection between the in-wheel motor drive device and the suspension device according to any one of claims 1 to 3, wherein the suspension member is a lower arm arranged below the in-wheel motor drive device and capable of swinging in the vertical direction. structure. 5. The connection structure for an in-wheel motor drive device and a suspension device according to claim 1, wherein said bracket is made by casting with aluminum as a main component.

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