CN110315959A - The connecting structure of in-wheel motor drive unit and draft hitch - Google Patents

Abstract

The present invention provides a connection structure between an in-wheel motor driving device and a suspension device, and provides a connection structure between an in-wheel motor and a suspension that can save space and improve suspension characteristics, strength, and durability. The connection structure of the present invention includes a suspension bracket (17) provided on the in-wheel motor drive device (10), a lower arm (42) of the suspension device, and a ball and socket for connecting the suspension bracket (17) and the lower arm. connector (51). The ball joint (51) has a stud (52) extending in the vertical direction, a ball (53) provided at an end of the stud, and a socket (54) enclosing the ball. The suspension bracket (17) has an internal space holding the outer side of the socket (54), a slit (58) connected to the internal space, and the socket (54) is fixed to the socket (54) by narrowing the slit (58). Bolts (59) and nuts (60) of the suspension bracket (17). The socket (54) faces the surface of the main body case (39) of the in-wheel motor drive device (10) across a gap (G) in the vertical direction.

Description

Connection structure of in-wheel motor drive unit and suspension unit

technical field

The present invention relates to an in-wheel motor drive device arranged inside a wheel to drive the wheel, and a suspension device connecting the in-wheel motor drive device to a vehicle body.

Background technique

Conventionally, as a connection structure between an in-wheel motor and a suspension, for example, the structures described in JP-A-2017-165279 (Patent Document 1) and Chinese Patent Application Publication No. CN106926656A (Patent Document 2) are known. The connection structures described in Patent Document 1 and Patent Document 2 include a bracket attached to and fixed to the in-wheel motor and extending in the vertical direction, a lower arm disposed below the in-wheel motor, and a ball joint connecting the lower arm to the bracket.

The ball joint includes: a ball portion and a socket slidably connected; and a stud coupled to the ball portion. The stud is fixed to the outer end in the vehicle width direction of the lower arm. The socket is fixed at the lower end of the bracket. The fixing structure of the socket is described in Patent Document 2.

FIG. 8 is a perspective view showing the connection state of the conventional in-wheel motor 7 and the lower arm 6 described in Patent Document 2. As shown in FIG. The bracket 2 is fastened to the housing 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, and corresponds to a portion surrounded by a circle with a dashed-dotted 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 such that the ball portion is located on the upper side and the stud is located on the lower side.

The socket of the ball joint is fixed to the lower end of the bracket 2 by three bolts 8 . Two of the three bolts 8 are shown in FIG. 8 . A screw 8 is shown enlarged in FIG. 9 . The head of each bolt 8 is located on the lower side, and the shaft portion extends upward, and the shaft portion is screwed into a female thread formed on the bracket 2 .

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2017-165279

Patent Document 2: Paragraph 0015 of CN106926656A Patent Application Publication of the People's Republic of China

However, in the conventional fixing structure described above, problems as described below arise. That is, the head portion of the bolt is arranged at the same height as the ball portion, and the shaft portion of the bolt extends upward from the head portion. Therefore, it is necessary to secure a space of a vertical dimension Le from the center of the spherical portion to the upper end of the bolt at a position below the in-wheel motor 7 . The internal space area of the rim for the in-wheel motor 7 is narrow, but in the above-mentioned conventional fixed structure, when occupying the space of the dimension Le, the in-wheel motor 7 can only be installed in the remaining space, resulting in that it cannot be installed in the rim. In-wheel motors of required size are arranged in the interior space area, and the constraints of in-wheel motors become larger. Therefore, space saving of the fixed structure is desired.

In addition, in the conventional fixing structure described above, as shown in FIG. 8 , the distance Lf from the axis O indicating the axle to the center of the ball and socket becomes large, resulting in a decrease in suspension characteristics.

In addition, in the aforementioned conventional fixing structure, as shown in FIG. 9 , tapped holes are formed in the bracket 2 and bolts 8 are screwed therein. Therefore, when the bracket 2 is made of an aluminum casting for the purpose of weight reduction, the strength of the screw threads of the bracket 2 may not be sufficiently ensured. For this reason, there are fears of chipping of thread threads due to pores included in the bracket 2 and chipping of thread threads over time due to repeated attachment and detachment of bolts 8 due to vehicle maintenance. Therefore, it is desired to improve the strength and durability of the fixing structure.

When using the number of thread teeth to make up for the lack of thread teeth, the length of the threaded hole of the bracket 2 becomes longer, resulting in an increasing dimension Le in the vertical direction from the center of the ball socket to the upper end of the bolt. Then, as mentioned above, the diameter of the in-wheel motor becomes smaller and the output decreases, resulting in a lower suspension characteristic.

Contents of the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coupling structure between an in-wheel motor and a suspension that can save space and improve suspension characteristics, strength, and durability.

means to solve the problem

In order to achieve this object, the connection structure between the in-wheel motor drive device and the suspension device of the present invention includes: a bracket provided on the in-wheel motor drive device; a suspension member displaceably connected to the vehicle body side member; A ball joint that attaches to a suspension member. The ball joint has a stud extending in the vertical direction, a ball provided at an 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 inner space on the outer side of the holding socket as a space connecting the upper opening and the lower opening, a slit connected to the inner space, and a slit through the constriction. A fastening mechanism that secures the socket to the bracket with narrow slits. In addition, the studs protrude from either one of the upper opening and the lower opening, and the remaining one faces the surface of the housing of the in-wheel motor drive device.

According to such a connection structure of the present invention, it is not necessary to provide a screw hole extending in the vertical direction in the bracket as in the conventional case. Therefore, compared with conventional ones, the vertical dimension of the bracket can be reduced to achieve space-saving of the connection structure. In addition, the strength and durability of the connection portion are improved. In addition, the diameter of the in-wheel motor drive device can be increased to increase the output. Alternatively, the center of the ball socket can be brought closer to the axle to improve suspension characteristics.

The structure of the fixing mechanism is not particularly limited. As one aspect of the present invention, the fixing mechanism has: a through hole formed in a pair of bracket parts facing each other across the slit of the bracket and extending to intersect the slit; the shaft portion passes through the through hole and the head is locked. a bolt on one side of the pair of bracket parts; and an internal thread part provided on the other side of the pair of bracket parts and screwed with the shaft part of the bolt. According to this aspect, since the bolt head and the female thread portion are provided on one and the other of the pair of bracket portions that face horizontally across the slit, the vertical angle of the bracket can be reduced compared to conventional ones. size. The internally threaded portion is, for example, a nut that is engaged with the other of the pair of bracket portions.

The configuration of the through holes is not particularly limited. As a preferred solution of the present invention, the through hole extends through the connecting portion between the inner space of the bracket and the slit, a recess is formed on the outer surface of the socket, and the shaft portion 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) as viewed from the suspension device. As still another preferred aspect of the present invention, the suspension member is a lower arm disposed below the in-wheel motor drive device and capable of swinging up and down. According to this aspect, in the suspension device in which the center of the spherical portion defines the steering axis, suspension characteristics are improved. As another aspect, the suspension member is an upper arm disposed above the in-wheel motor drive device and capable of swinging in the vertical direction.

The material of the bracket is not particularly limited. As one aspect of the present invention, the bracket is a cast product mainly composed of aluminum. According to this aspect, weight reduction and cost reduction of the bracket can be achieved. Alternatively, the bracket may be a metal product other than aluminum, or may be a forged product.

Invention effect

In this way, according to the present invention, compared with the past, the connection structure of the in-wheel motor drive unit and the suspension device can realize space-saving, the outer diameter of the in-wheel motor drive unit can be increased, or the center of the spherical portion can be brought closer to the axle shaft. Improve suspension characteristics. In addition, the strength and durability of the connection structure are improved. In addition, weight reduction and cost reduction of the bracket can be achieved.

Description of 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.

Fig. 3 is a schematic diagram showing a suspension bracket of the in-wheel motor drive device.

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.

Fig. 5 is a longitudinal sectional view showing the connection structure of the embodiment.

FIG. 6 is a transverse cross-sectional view showing the connection structure of this embodiment.

Fig. 7 is a schematic diagram showing a coupling structure of an in-wheel motor drive device and a suspension device of a comparative example.

Fig. 8 is a perspective view showing a conventional in-wheel motor and a connected state of a lower arm.

Fig. 9 is an enlarged cross-sectional view showing the socket fixing structure of Fig. 8 .

Explanation of reference signs

10 In-wheel motor drive unit, 11 Hub bearing, 17 Suspension bracket, 17b Upper end, 7c Vertical center, 17d Lower end, 17f Outer side, 17g, 17j Bracket part, 17h Through hole (fixing mechanism) , 21 motor part, 24 stator, 29 motor housing, 39 main body housing, 41 pillar, 42 lower arm, 51 ball joint, 52 stud, 53 ball part, 54 socket, 56 inner space, 58 slit, 59 bolts (fixing mechanism), 60 nuts (fixing mechanism), K steering axis, O axis (axle), W rim (wheel).

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a developed sectional view showing an in-wheel motor drive device. FIG. 2 is a schematic diagram showing a coupling structure of an in-wheel motor drive device and a suspension device according to an embodiment of the present invention, showing the interior of the in-wheel motor drive device with phantom lines as viewed along the axle direction. As shown in FIG. 1 , the in-wheel motor driving device 10 includes: a hub bearing portion 11 provided at the center of the wheel; a motor portion 21 that drives the wheel; . The motor unit 21 and the reduction unit 31 are arranged offset from the axis O of the hub bearing unit 11 . The axis O extends in the vehicle width direction and coincides with the axle. At the position in the direction of the axis O, the hub bearing part 11 is disposed on one side (outer disk side) of the in-wheel motor drive device 10 in the axial direction, and the motor part 21 is disposed on the other side (inner disk side) of the in-wheel motor drive device 10 in the axial direction. The deceleration unit 31 is arranged on the axial side of the motor unit 21 , and the position of the deceleration unit 31 in the axial direction overlaps the position of the hub bearing unit 11 in the axial direction.

The wheel is formed by mounting a tire (not shown) on the outer periphery of the rim W shown in FIG. 2 . The in-wheel motor drive device 10 is arranged in the inner space area of the rim W. As shown in FIG. The hub bearing unit 11 and the decelerating unit 31 are accommodated in the inner space area of the rim W. As shown in FIG. The motor unit 21 protrudes from the inner space area of the rim W to the other side (inner disc side) in the axial direction, but the motor unit 21 may be accommodated in the inner space area of the rim W as a modified example not shown.

The hub bearing part 11 is a rotating inner ring and a fixed outer ring, and has an inner ring 12 as a rotating ring (hub ring) coupled with the rim W; The outer ring 13; 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 main body case 39 of the speed reduction unit 31 by a fastening structure such as bolts. The front portion 39 f is a case wall portion covering one side end of the deceleration unit 31 in the axis O direction of the main body case 39 .

The motor unit 21 has a motor rotating shaft 22 , a rotor 23 , a stator 24 , and a motor case 29 , which are arranged in this order from the axis M of the motor unit 21 toward the radially outer side. The motor part 21 is a radial gap motor in the form of an inner rotor and an outer stator, and may also be other forms of poles. For example, although not shown, the motor unit 21 may be an axial gap motor. The motor case 29 surrounds the outer periphery of the stator 24 . One side end of the motor case 29 in the direction of the axis M is joined to the rear surface portion 39 b of the main body case 39 of the deceleration unit 31 . The other end in the direction of the axis M of the motor case 29 is sealed by a plate-shaped motor case cover 29v. The rear portion 39 b is a case wall portion covering the other side end in the direction of the axis O of the deceleration unit 31 in the main body case 39 .

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

Both end portions of the motor rotating shaft 22 are rotatably supported by the rear surface portion 39 b of the main body case 39 and the motor case cover 29 v of the motor unit 21 via rolling bearings 27 and 28 , respectively.

An axis M serving as a rotation center of the motor rotating shaft 22 and the rotor 23 extends parallel to the axis O of the hub bearing 11 . That is, the motor unit 21 is arranged to be offset from the axis O of the hub bearing unit 11 . For example, as shown in FIG. 2 , the axis M and the axis O of the electric motor unit are arranged offset in the vehicle front-rear direction, and specifically arranged at a position closer to the front of the vehicle than the axis O.

As shown in FIG. 1 , the reduction unit 31 has: an input shaft 32 coaxially coupled with the motor rotating 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; the intermediate shaft 35 combined with the centers of these intermediate gears 34, 36; the output shaft 38 connected to the inner ring 12 of the hub bearing portion 11; the output gear 37 coaxially arranged on the outer peripheral surface of the output shaft 38; The main body housing 39 of these plural gears and rotating shafts. The main body case 39 is also referred to as a deceleration unit case because it constitutes the outer shell of the deceleration unit 31 .

The input gear 33 is a helical gear with external teeth. The input shaft 32 has a hollow structure, and the axial end 22e of the motor rotating shaft 22 is inserted into the hollow hole 32h of the input shaft 32 to be spline-fitted in a relatively non-rotatable manner (including zigzag fit, the same applies hereinafter). The input shaft 32 is rotatably supported by a front portion 39f and a rear portion 39b of the main body case 39 on both end sides of the input gear 33 via rolling bearings 32a, 32b, respectively.

An axis N serving as the center of rotation of the intermediate shaft 35 of the deceleration unit 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 main body case 39 via rolling bearings 35a, 35b. The first intermediate gear 34 is coaxially provided at the other end portion of the intermediate shaft 35 in the axis N direction. A second intermediate gear 36 is coaxially provided in a central area of the intermediate shaft 35 in the direction of the axis N.

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 that of the second intermediate gear 36 . The large-diameter first intermediate gear 34 is disposed on the other side in the axis N direction from the second intermediate gear 36 , and meshes with the small-diameter input gear 33 . The small-diameter second intermediate gear 36 is arranged on the side in the axis N direction relative to the first intermediate gear 34 , and meshes with the large-diameter output gear 37 .

As shown in FIG. 2 , the axis N of the intermediate shaft 35 is disposed above the axes O and M. As shown in FIG. In addition, the axis N of the intermediate shaft 35 is arranged at a position in front of the vehicle relative to the axis O and in a position rearward of the vehicle relative to the axis M. The deceleration unit 31 is a three-shaft parallel shaft gear reducer having axes O, N, and M arranged at intervals in the vehicle front-rear direction and extending parallel to each other, and performs deceleration in two stages. It should be noted that, as a modified example not shown, the reduction unit 31 may be a multi-stage parallel shaft gear reducer having a plurality of intermediate shafts.

Returning to FIG. 1 for description, the output gear 37 is a helical gear with external teeth, and is provided coaxially at the central portion of the axis O of the output shaft 38 . The output shaft 38 extends along the axis O. One end portion 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 to be relatively non-rotatable. A central portion of the output shaft 38 in the axis O direction is rotatably supported by a front portion 39f of the main body case 39 via a rolling bearing 38a at a position radially outer from the other end portion of the inner ring 12 in the axis O direction. The other end portion of the output shaft 38 in the direction of the axis O is rotatably supported by the rear surface portion 39b of the main body case 39 via a rolling bearing 38b.

As shown in FIG. 1 , the deceleration portion 31 is driven by the engagement of the small-diameter driving gear and the large-diameter driven gear, that is, the engagement of the input gear 33 and the first intermediate gear 34, and the engagement of the second intermediate gear 36 and the output gear 37. The rotation of the input shaft 32 is decelerated and transmitted to the output shaft 38 . Rotary elements from the input shaft 32 to the output shaft 38 of the speed reduction unit 31 constitute a drive transmission path that transmits the rotation of the motor unit 21 to the inner ring 12 of the hub bearing unit 11 .

The main body case 39 includes a cylindrical portion in addition to the front portion 39f and the rear portion 39b described above. The cylindrical portion covers the internal components of the deceleration unit 31 so as to surround the axes O, N, and M extending parallel to each other. The plate-shaped front portion 39f covers the internal components of the deceleration unit 31 from one side in the axial direction, and is joined to one end of the cylindrical portion. The plate-shaped back portion 39b covers the internal parts of the decelerating unit 31 from the other side in the axial direction, and is joined to the other end of the cylindrical portion. The back portion 39 b of the main body case 39 is also a partition wall that is combined with the motor case 29 and separates the internal space of the deceleration unit 31 and the internal space of the motor unit 21 . The motor case 29 is supported by the main body case 39 and protrudes from the main body case 39 to the other side in the axial direction.

The main body case 39 defines the inner space of the speed reduction unit 31 and accommodates all the rotating elements (rotation shafts and gears) of the speed reduction unit 31 in the inner space. As shown in FIG. 2, the lower part of the main body case 39 becomes the oil storage part 39t. The height position of the oil storage part 39t overlaps with the height position of the lower part of the motor part 21 . Lubricating oil for lubricating the motor unit 21 and the deceleration unit 31 is stored in an oil reservoir 39 t occupying a lower portion of the inner space of the main body case 39 .

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

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

Fig. 3 is a schematic view showing the suspension bracket in which the in-wheel motor drive device is attached to the suspension device, as seen from the vehicle front-rear direction. The suspension bracket 17 is fixed to the outer wall surface of the main body case 39 . Referring to FIG. 2 , in the vehicle front-rear direction, the suspension bracket 17 is arranged on the side opposite to the motor unit 21 , specifically, it is arranged offset to the vehicle rear.

As shown in FIG. 3 , the suspension bracket 17 extends in the vertical direction. The upper end portion 17b of the suspension bracket 17 is disposed on the inside of the speed reduction portion 31 in the vehicle width direction, and protrudes from the internal space area of the rim W. As shown in FIG. In addition, the upper end portion 17b is arranged at a position behind the vehicle than the motor portion 21 . In addition, although the upper end portion 17 b is disposed on the upper portion of the in-wheel motor drive device 10 , it is located at a lower position than the upper portion of the decelerating 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 .

In order to reduce the unsprung load of the suspension device, the suspension bracket 17 is preferably made of aluminum or other light metal products. In addition, the suspension bracket 17 may also be an aluminum casting.

The strut 41 is a suspension member extending in the vertical direction, and is specifically a shock absorber that combines a damping mechanism such as a damper and an elastic mechanism such as a coil spring. Viewed from the suspension member, when the in-wheel motor drive device 10 mounted on the unsprung 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 arm 19 is provided at a vertically central portion 17 c of the suspension bracket 17 . The tie rod arm 19 protrudes from the suspension bracket 17 in the vehicle front-rear direction. The front end portion of the tie rod arm 19 is connected to a tie rod of a steering device (not shown).

The lower end portion 17d of the suspension bracket 17 is disposed below the deceleration portion 31 and accommodated in the internal space region of the rim W. As shown in FIG. Referring to FIG. 2 , a gap G in the vertical direction is formed between the lower end portion 17 d and the main body case 39 . In addition, the height position of the lower end portion 17d overlaps with the height position of the oil storage portion 39t. The lower end portion 17d is connected to the lower arm 42 via the ball joint 51 . A straight line connecting the center of the ball portion 53 of the ball joint 51 and the upper end of the strut 41 constitutes the steering axis K. As shown in FIG. The in-wheel motor drive 10 is steerable together with the wheels W about the steering axis K. The center of the ball portion 53 is also referred to as a hard point.

The lower arm 42 is a suspension member disposed below the in-wheel motor drive unit 10 and the suspension bracket 17 and extends in the vehicle width direction, and has vehicle width inner ends 43 , 44 and a vehicle width outer end 45 . The inner ends 43 and 44 in the vehicle width direction are connected to an unillustrated vehicle body side member via a pivot shaft. The outer end 45 in the vehicle width direction is arranged directly below the lower end portion 17 d and is coupled to the stud 52 of the ball joint 51 . It should be noted that, in FIG. 2 , the lower arm 42 is simplified by a line diagram.

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

The lower arm 42 and the strut 41 constitute a suspension device. In this embodiment, it is a strut type suspension device. In addition, a vehicle body side member refers to the member attached to the vehicle body side viewed from the demonstrated member.

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

FIG. 4 is a schematic diagram illustrating 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 showing the periphery of the ball joint 51 in FIG. 2 . FIG. 5 is a longitudinal sectional view showing the connection structure of this embodiment, and is an enlarged view showing the periphery of the ball joint 51 in FIG. 2 . Fig. 6 is a transverse sectional view showing the coupling structure of the embodiment, showing a cross section of the embodiment taken along the A-A plane shown in Figs. 4 and 5 . The ball joint 51 has a stud 52 extending in the vertical direction, a ball portion 53 provided at an end of the stud 52 , and a socket 54 connected to the ball 53 .

The stud 52 of this embodiment extends in the vertical direction, and is connected to the ball part 53 at the upper end. The stud 52 and the ball portion 53 are one member, so they are also called ball studs. The lower end of the stud 52 passes through a through hole formed in the vehicle width direction outer end 45 of the lower arm 42 and extends in the vertical direction, and protrudes downward from the vehicle width direction outer end 45 . An external thread is formed on the outer periphery of the protruding portion, and is screwed into the nut 55 . The stud 52 is fixed to the outer end 45 in the vehicle width direction by a fixing mechanism such as a nut 55 . Preferably, a washer 61 is interposed between the nut 55 and the lower surface of the lower end portion 17d.

The socket 54 has a spherical concave portion 54q in the center that encloses the spherical portion 53 . The spherical recess 54 q is accompanied by an opening on the lower surface of the socket 54 . The inner diameter of the opening of the spherical concave portion 54 q is smaller than the outer diameter of the spherical portion 53 . Therefore, the spherical portion 53 does not come out of the spherical concave portion 54q. The stud 52 protrudes downward from the opening of the spherical recess 54q. The ball portion 53 is slidable in the socket 54, and the posture of the stud 52 is continuously changed in all directions as viewed from the socket 54.

The lower end portion 17d of the suspension bracket 17 defines an internal space 56 . The internal space 56 is a circular hole extending in the vertical direction through the lower end portion 17d. Therefore, the internal space 56 includes the upper opening 56b and the lower opening 56c, and is a space connecting the upper opening 56b and the lower opening 56c. The inner space 56 accommodates the socket 54 . The inner surface of the lower end portion 17 d defining the internal space 56 is in contact with the outer surface of the socket 54 . This contact may be a loose fit or press fit. As shown in FIG. 6 , the inner surface of the inner space 56 and the outer surface of the socket 54 have a circular cross section. It should be noted that referring to FIGS. 4 and 5 , the inner surface of the internal space 56 is a cylindrical surface. As a modified example not shown, the inner surface of the internal space 56 may be a conical surface. The stud 52 protrudes from the lower opening 56c. The upper opening 56b faces the surface of the main body case 39 at the lower part of the in-wheel motor drive device 10 ( FIG. 2 ).

As shown in FIG. 2 , the upper surface of the lower end portion 17 d and the socket 54 housed in the internal space 56 face the lower surface of the in-wheel motor drive device 10 via the gap G in the vertical direction. The lower surface is specifically the surface of the main body case 39 . Thereby, the clearance gap G of an up-down direction can be ensured between the lower end part 17d and the main body case 39. As shown in FIG.

A protrusion 54p is formed at the lower portion of the socket 54 . The protrusion 54 p is, for example, a small flange formed so as to be coplanar with the lower surface of the socket 54 . The protrusion 54p is in contact with the lower surface of the lower end portion 17d. As a result, the socket 54 restricts the upward escape of the internal space 56 .

The lower end portion 17 d and the outer end 45 in the vehicle width direction are arranged at intervals in the vertical direction, and a stud 52 is bridged between them. The stud 52 is surrounded by a bellows-shaped rubber boot 57 between the lower end portion 17 d and the vehicle width direction outer end 45 . One end of the rubber sleeve 57 is connected to the lower surface of the socket 54 to seal the ball part 53 . The other end of the rubber boot 57 is connected to the outer end 45 in the vehicle width direction to seal the stud 52 . Accordingly, the ball portion 53 and the stud 52 are 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 to the internal space 56 . The lower end portion 17d includes a pair of bracket portions 17g, 17j facing across a slit 58 .

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 the one bracket portion 17g to the other bracket portion 17j, and intersects the slit 58 . The through hole 17h is disposed in the vertically central region of the lower end portion 17d. A bolt 59 passes through the through hole 17h.

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

The through hole 17h, the bolt 59 and the nut 60 are fixing means for fixing the socket 54 to the suspension bracket 17 . When the bolt 59 and the nut 60 are tightened, the slit 58 narrows, and the inner surface of the lower end portion 17 d defining the internal space 56 tightly binds the outer surface of the socket 54 . Thus, the socket 54 is 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 is connected to both the slit 58 and the internal space 56 . It should be noted that, as a modified example not shown, the through hole 17h may be a through hole connected only to the slit 58 .

A circumferential groove 54g extending along the entire circumference is formed on 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.

Referring to FIG. 2 , according to the present embodiment, the ball studs are arranged vertically extending such that the stud 52 is away from the axis O (axle) of the in-wheel motor drive device 10 and the ball portion 53 is close to the axis O. Then, the socket 54 enclosing the spherical portion 53 is fixed to the suspension bracket 17 of the in-wheel motor drive device 10, and the stud 52 is fixed to the lower arm 42 of the suspension device. Furthermore, the suspension bracket 17 is fixed to the socket 54 by tightening the socket 54 by narrowing the slit 58 in the horizontal direction. Thus, the fixing mechanism between the suspension bracket 17 and the socket 54 is sufficient due to the vertical dimension of the socket 54 and does not protrude from the ball portion 53 in the vertical direction. Therefore, the center of the spherical portion 53 can be brought close to the axis O. As shown in FIG.

In FIG. 2, the dimension Lr from the axis O of this embodiment to the lower surface of the main body case 39, the gap width Lg of the gap G in the vertical direction, the dimension Ld from the upper surface of the lower end portion 17d to the center of the spherical portion 53, The distance Lb from the axis O to the center of the spherical portion 53 is represented by Equation 1 below.

[Formula 1]

Lr+Lg+Ld=Lb

FIG. 7 is a schematic view showing a connection structure between an in-wheel motor drive device and a suspension device according to a comparative example, and shows a state viewed in the axle direction similarly to FIG. 2 . Regarding the comparative example, the same reference numerals are assigned to the same configurations as those of the above-mentioned embodiments, and description thereof will be omitted, and different configurations will be described below.

In the comparative example of FIG. 7 , a flange 54 f is formed on the socket 54 instead of the above-mentioned slit 58 . The flange 54f is an annular plate having a thickness in the vertical direction. Holes penetrating in the plate thickness direction are formed at intervals in the circumferential direction on the flange 54f. In addition, a plurality of screw holes 17n extending upward are drilled in the lower surface of the lower end portion 17d. The arrangement of the threaded holes 17n corresponds to the through-holes of the flange 54f. And the bolt 54b penetrates the through-hole of the flange 54f, and is screwed in 17 n of screw holes. Thus, the socket 54 is fixed to the lower end portion 17d.

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

In the comparative example of FIG. 7, the dimension Lr from the axis O to the lower surface of the main body case 39, the gap width Lg of the gap G in the vertical direction, the dimension Le from the upper surface of the lower end portion 17d to the center of the spherical portion 53, and The distance Lf from the axis O to the center of the spherical portion 53 is represented by Equation 2 below.

[Formula 2]

Lr+Lg+Le=Lf

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

Comparing Formula 1 and Formula 2, Lb<Lf. The reason for this is 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 or smaller.

As shown in FIG. 2 , the connection structure between the in-wheel motor drive device and the suspension device in this embodiment includes: a suspension bracket 17 provided on the in-wheel motor drive device 10; and a lower arm 42 displaceably connected to the vehicle body side member. ; the ball joint 51 that connects the suspension bracket 17 to the lower arm 42 . As shown in FIG. 4 , the ball joint 51 has a stud 52 extending in the vertical direction, a ball portion 53 provided at the end of the stud 52 , and a socket connected to the ball portion 53 via a spherical recess 54q enclosing the ball portion 53 . Litter 54. The lower end portion 17d of the suspension bracket 17 has an upper opening 56b, a lower opening 56c, a space connecting the upper opening 56b and the lower opening 56c and an inner space for holding the outer surface of the socket 54, and a slit connected to the inner space. 58 ( FIG. 6 ), and bolts 59 and nuts 60 that secure the socket 54 to the suspension bracket 17 by narrowing the slit 58 . The stud 52 protrudes from the lower opening 56 c , and the upper opening 56 b faces the surface of the main body case 39 of the in-wheel motor drive device 10 . The socket 54 does not protrude from the upper opening 56b. Therefore, the gap G in the vertical direction can secure the clearance of the dimension Lg.

Therefore, referring to FIG. 2 , the dimension Ld from the upper surface of the lower end portion 17 d to the center of the ball portion 53 can be reduced to achieve space saving of the connection structure. In addition, there is no need to tap the lower end portion 17d to provide screw threads as in the conventional fixing mechanism, and the suspension bracket 17 can be made of aluminum casting to achieve cost reduction and weight reduction. In addition, the diameter of the output shaft gear 37 can be increased to increase the torque of the wheel. Alternatively, the suspension characteristic can be improved by reducing the distance Lb from the axis O to the center of the spherical portion 53 .

In addition, the fixing mechanism for fixing the socket 54 of the present embodiment to the lower end portion 17d has a through hole 17h extending to cross the slit 58, and a bracket portion through which the shaft passes through the through hole 17h and locks the head to one side. The 17g bolt 59 and the nut 60 which are arranged adjacent to the other bracket portion 17j and are screwed to the shaft portion of the bolt 59 . This eliminates the need to arrange the heads of the bolts 59 and the nuts 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 joint between the internal space 56 and the slit 58, and a circumferential groove 54g is formed on the outer surface of the socket 54, and the shaft portion of the bolt 59 engages with the circumferential groove 54g. Thereby, the socket 54 is prevented from coming out from the internal space 56 .

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the embodiments shown in the drawings. Various modifications and variations can be added to the embodiments shown in the drawings within the same or equivalent scope as the present invention. For example, it is also possible to extract a part of the configuration from the one embodiment described above, extract another part of the configuration from the other embodiment described above, and combine these extracted configurations.

Industrial Applicability

The present invention is advantageously utilized in electric vehicles and hybrid vehicles.

Claims (5)

1. A connection structure between an in-wheel motor driving device and a suspension device, which has: brackets for the in-wheel motor drives; a suspension member displaceably connected to a body side member; and a ball joint connecting said bracket to said suspension member, The ball joint has a stud extending in the vertical direction, a ball provided at an end of the stud, and a socket enclosing the ball, The bracket has an upper opening, a lower opening, an inner space for holding an outer surface of the socket as a space connecting the upper opening and the lower opening, a slit connected to the inner space, and a a fixing mechanism that narrows the slit to fix the socket to the bracket, The studs protrude from either one of the upper opening and the lower opening, and the remaining one faces a surface of the housing of the in-wheel motor drive device. 2. The connection structure between the in-wheel motor drive device and the suspension device according to claim 1, wherein: The fixing mechanism has a through hole formed in a pair of bracket parts facing across the slit and extending across the slit; the shaft passes through the through hole and the head is locked to the through hole. a bolt on one side of the pair of bracket parts; and an internal thread part provided on the other side of the pair of bracket parts and screwed with the shaft part of the bolt. 3. The connection structure between the in-wheel motor drive device and the suspension device according to claim 2, wherein: The through hole extends through the connecting portion of the inner space and the slit, A recess is formed on the outer surface of the socket, The shaft portion of the bolt engages with the concave portion. 4. The connection structure 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 disposed below the in-wheel motor drive device and capable of swinging up and down. 5. The connection structure between the in-wheel motor drive device and the suspension device according to any one of claims 1 to 3, wherein: The bracket is a casting product mainly composed of aluminum.