JP2021123128A - Vehicular suspension arm - Google Patents

Abstract

To provide a suspension arm which is light-weight, yet can improve strength and rigidity to inhibit deformation caused when bending moment is input, and avoids interference with peripheral components to improve mountability.SOLUTION: An axis of a ball joint inclines relative to an axis of a bush when viewed in a vehicle width direction. An arm body 1A comprises an upper member 10 and a lower member 20. An upper ball joint press-fitting part 12 is formed at the upper member 10 by burring. A lower ball joint press-fitting part 22 is formed at the lower member 20 by burring. An outer portion as seen in the vehicle width direction of the arm body 1A is open.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle suspension arm constituting an automobile suspension device, and particularly belongs to the technical field of a structure in which a plurality of plate materials are combined.

Conventionally, a double wishbone suspension device has been known as an automobile suspension device. The double wishbone suspension device is composed of an upper arm and a lower arm that are swingably connected to the vehicle body in the vertical direction, and a knuckle that connects the outer ends of the upper arm and the lower arm in the vehicle width direction.

Cast products and forged products are known as upper arms of double wishbone suspension devices. For example, those made of a single plate material as disclosed in Patent Document 1 and those disclosed in Patent Document 2 are disclosed. A hollow structure in which two plate materials are combined is also known.

Japanese Unexamined Patent Publication No. 2000-1420555 Japanese Unexamined Patent Publication No. 10-37945

By the way, as described above, the upper arm used for the double wishbone suspension was made by casting or forging, but as the weight reduction of the automobile is required, the upper arm having a sheet metal structure is described in Patent Documents 1 and 2. Is also being adopted.

Further, the upper arm is attached to the vehicle body by a bush on the inside in the vehicle width direction, and a ball joint connected to the knuckle is provided on the outside in the vehicle width direction. The ball joint axis and the bush axis are often laid out so as to be orthogonal to each other, but depending on the vehicle, a layout in which the ball joint axis is not orthogonal to the bush axis may be adopted from the viewpoint of steering stability. At this time, since the bending moment is input to the upper arm, the following problems occur in the arm as in Patent Documents 1 and 2.

That is, since the upper arm disclosed in Patent Document 1 has an open cross-sectional structure, it is vulnerable to torsional input. Therefore, unless the strength and rigidity are secured by increasing the plate thickness of the plate material constituting the upper arm, the upper arm can be used. Deformation when a bending moment is input cannot be suppressed. Therefore, if the ball joint shaft is used in a layout that is not orthogonal to the bush shaft, the weight of the upper arm will increase.

Further, although the upper arm disclosed in Patent Document 2 has a closed cross-section structure, its cross section is large, and it has a distorted shape because interference with peripheral parts must be avoided. It is considered that the decrease in strength and rigidity caused by this can be dealt with by increasing the plate thickness of the plate material constituting the upper arm, but the weight also increases.

The present invention has been made in view of this point, and an object of the present invention is to increase strength and rigidity to suppress deformation at the time of inputting a bending moment while being lightweight, and to interfere with peripheral parts. It is an object of the present invention to provide a suspension arm having a good mountability by avoiding the above.

In order to achieve the above object, in the present invention, on the premise of a layout in which the ball joint shaft is not orthogonal to the bush shaft, the suspension arm has a vertically divided closed cross-sectional structure, and the ball joint press-fitting portion is an upper member and a lower member. The suspension arms were formed by burring and opposed to each other to open the outer end side of the suspension arm in the vehicle width direction.

According to the first invention, an arm body, a tubular bush attached to the inside of the arm body in the vehicle width direction and having an axis extending in the vehicle front-rear direction, and a tubular bush attached to the outside of the arm body in the vehicle width direction are attached in the vertical direction. In a vehicle suspension arm provided with a ball joint having an extending axis and supported by the bush so as to swing in the vertical direction with respect to the vehicle body, the ball is relative to the axis of the bush when viewed from the vehicle width direction. The bush and the ball joint are arranged so that the axis of the joint is inclined, and the upper member is made of a plate material formed so as to bulge upward and open downward, and constitutes an upper member of the upper side of the arm body. It is made of a plate material that is formed so as to bulge downward and open upward, and is joined to the lower members constituting the lower side of the arm body in a state where the open portions are aligned with each other, and the upper member is in the vehicle width direction. A cylindrical burring process is applied to the outside so as to project downward to form an upper ball joint press-fitting portion into which the ball joint is press-fitted. Correspondingly, burring is performed in a cylindrical shape protruding upward to form a lower ball joint press-fitting portion into which the ball joint is press-fitted, and the upper ball joint press-fitting portion and the lower ball joint press-fitting portion in the arm body are formed. The outer portion in the vehicle width direction rather than the portion is characterized in that it is open toward the outer side in the vehicle width direction.

According to this configuration, when viewed from the vehicle width direction, the axis of the ball joint is inclined with respect to the axis of the bush, so that the layout is such that the ball joint axis is not orthogonal to the bush axis, for example, improving steering stability. Will be possible.

Then, since the hollow arm body is formed by the upper member and the lower member formed by molding the plate material, the suspension arm becomes highly rigid and lightweight. Since the ball joint is attached to the arm body by being press-fitted into the upper ball joint press-fitting portion of the upper member and the lower ball joint press-fitting portion of the lower member, it is supported by both the upper member and the lower member. Therefore, high support rigidity can be obtained.

Since the outer part in the vehicle width direction is open toward the outer side in the vehicle width direction from the upper ball joint press-fitting part and the lower ball joint press-fitting part of the arm body, the vertical flange on the outer side in the vehicle width direction is eliminated, and the peripheral parts and the peripheral parts are removed. It is possible to secure a wide gap.

In the second invention, a front bush mounting cylinder portion and a rear bush mounting cylinder portion to which the bushes are mounted are provided inside the arm body in the vehicle width direction at intervals in the vehicle front-rear direction, respectively, and the upper side thereof. When a virtual plane passing through the center of the ball joint press-fitting portion and the ball joint press-fitted into the lower ball joint press-fitting portion, the center of the front bush mounting cylinder portion, and the center of the rear bush mounting cylinder portion is set. The upper member and the lower member have substantially symmetric shapes with the virtual plane as a symmetric plane, except for the upper ball joint press-fitting portion, the lower ball joint press-fitting portion, and the peripheral portions of both press-fitting portions. It is characterized by being.

That is, the center of the ball joint, the center of the front bush mounting cylinder, and the center of the rear bush mounting cylinder are reference points at the time of design, and are also called hard points (H / P). Since the upper member and the lower member have a symmetrical shape except for the portion where the ball joint press-fitting portion is formed with the virtual plane defined by these three hard points as the plane of symmetry, most of the vertical cross sections of the suspension arm. Is almost vertically symmetrical. This makes it possible to minimize the cross-sectional shape while ensuring the rigidity of the suspension arm.

In the third invention, an upper annular flat plate portion extending in an annular shape is formed around the upper ball joint press-fitting portion, and the upper annular flat plate portion is compared with a portion around the upper annular flat plate portion in the upper member. It is characterized by being located below.

According to this configuration, by positioning the upper annular flat plate portion formed around the upper ball joint press-fitting portion at the bottom, the portion of the arm body that supports the ball joint becomes thin.

In the fourth invention, a lower annular flat plate portion extending in an annular shape is formed around the lower ball joint press-fitting portion, and the lower annular flat plate portion is the lower annular flat plate portion of the lower member. It is characterized in that it is located above the surrounding part.

According to this configuration, by positioning the lower annular flat plate portion formed around the lower ball joint press-fitting portion on the upper side, the portion of the arm body that supports the ball joint becomes thinner.

In the fifth aspect of the invention, the outer edge portion of the upper member in the vehicle width direction extends in an arc shape along the peripheral edge portion of the upper ball joint press-fitting portion, and the outer edge portion of the lower member in the vehicle width direction is formed. It is characterized in that it extends in an arc shape along the peripheral edge portion of the lower ball joint press-fitting portion.

According to this configuration, the outer portions of the upper member and the lower member in the vehicle width direction are secured by the minimum necessary width along the peripheral edges of the upper ball joint press-fitting portion and the lower ball joint press-fitting portion. ..

In the sixth invention, the upper member is formed so that the amount of bulging upward increases as it approaches the inner end in the vehicle width direction, and the lower member decreases downward as it approaches the inner end in the vehicle width direction. It is characterized in that it is molded so that the amount of swelling is large.

According to this configuration, the cross section becomes larger in the vertical direction as it approaches the side connected to the vehicle body, so that the dimension of the cross section in the front-rear direction can be shortened on the side connected to the vehicle body.

The seventh invention is characterized in that the lower end portion of the upper ball joint press-fitting portion and the upper end portion of the lower ball joint press-fitting portion are arranged with a gap in the vertical direction.

According to this configuration, the upper ball joint press-fitting portion and the lower ball joint press-fitting portion do not come into contact with each other.

According to the first invention, when the layout is such that the ball joint shaft is not orthogonal to the bush shaft, a hollow suspension arm is formed by the upper member and the lower member, so that a highly rigid and lightweight suspension arm can be obtained. Obtainable. Then, by press-fitting the ball joint into the upper ball joint press-fitting portion and the lower ball joint press-fitting portion, the ball joint can be supported by both the upper member and the lower member, and high support rigidity can be obtained. .. Further, since the outer portion in the vehicle width direction is opened toward the outer side in the vehicle width direction from the upper ball joint press-fitting portion and the lower ball joint press-fitting portion of the suspension arm, a wide gap with peripheral parts can be secured. , It is possible to improve the mountability on a vehicle.

According to the second invention, the upper member and the lower member are substantially symmetrical with a virtual plane passing through the center of the ball joint, the center of the front bush mounting cylinder, and the center of the rear bush mounting cylinder. Since the shape is symmetrical, it is possible to minimize the cross-sectional shape and secure a wide gap with the peripheral parts while ensuring the rigidity of the suspension arm.

According to the third invention, since the upper annular flat plate portion is formed around the upper ball joint press-fitting portion and the upper annular flat plate portion is positioned below, the portion of the arm body that supports the ball joint becomes thin. , The mountability on the vehicle becomes even better.

According to the fourth invention, a lower annular flat plate portion is formed around the lower ball joint press-fitting portion, and the lower annular flat plate portion is positioned upward, so that a portion of the arm body that supports the ball joint. Becomes thinner, and the mountability on the vehicle becomes even better.

According to the fifth invention, the width of the outer portion of the upper member and the lower member in the vehicle width direction can be minimized, and a wide gap with the peripheral parts can be secured.

According to the sixth invention, the cross section becomes larger in the vertical direction as it approaches the side connected to the vehicle body, so that the dimension in the front-rear direction of the cross section is shortened on the side connected to the vehicle body while ensuring the necessary rigidity. can do.

According to the seventh invention, the upper ball joint press-fitting portion and the lower ball joint press-fitting portion can be prevented from coming into contact with each other.

It is a perspective view which looked at the suspension arm for a vehicle which concerns on embodiment of this invention from above. It is a top view of the suspension arm for a vehicle which concerns on embodiment. It is a figure which looked at the suspension arm for a vehicle which concerns on embodiment from the front of a vehicle. It is a figure which looked at the suspension arm for a vehicle which concerns on embodiment from the outside in the vehicle width direction. It is a figure which looked at the suspension arm for a vehicle which concerns on embodiment from the inside in the vehicle width direction. It is a perspective view which looked at the upper member from above. It is a perspective view which looked at the lower member from above. It is a cross-sectional view which shows the state which the ball joint is attached to the arm body, and corresponds to line VIII-VIII in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is essentially merely an example and is not intended to limit the present invention, its application or its use.

FIG. 1 is a perspective view of the vehicle suspension arm 1 according to the embodiment of the present invention as viewed from above. The suspension arm 1 is used, for example, as an upper arm of a double wishbone suspension device (front wheel suspension device) mounted on the front side of an automobile, and the inside in the vehicle width direction is attached to the vehicle body by the front bush B1 and the rear bush B2. On the other hand, the ball joint 40 (shown in FIG. 8) is attached to the outside in the vehicle width direction while being supported so as to be swingable in the vertical direction. Although not shown, the double wishbone suspension device includes a lower arm and a knuckle for connecting the upper arm and the outer end portions of the lower arm in the vehicle width direction in addition to the upper arm, so that the front wheels can rotate on the knuckle. It is attached. The upper and lower parts of the knuckle are rotatably connected to the upper arm and the lower arm by a ball joint 40. A steering device is provided at the front of the automobile, and the knuckle is rotated by the steering device, which enables steering of the front wheels.

(Overall configuration of suspension arm 1)
As shown in FIG. 1, the suspension arm 1 according to this embodiment has an arm body 1A, a tubular front bush B1 which is attached to the inside of the arm body 1A in the vehicle width direction and has an axis extending in the vehicle front-rear direction, and a rear bush B1. It includes a side bush B2 and a ball joint 40 (shown only in FIG. 8) which is attached to the outside of the arm body 1A in the vehicle width direction and has an axis extending in the vertical direction. The front bush B1 includes a bush body B11 made of an elastic material such as rubber, and a metal tubular member B12 fixed to the center of the bush body B11. The tubular member B12 is fixed to the vehicle body by a fastening member such as a bolt. The center line of the tubular member B12 is located on the axis of the front bush B1. The rear bush B2 is also configured in the same manner as the front bush B1, and includes a bush main body B21 and a tubular member B22. Both the axis of the front bush B1 and the axis of the rear bush B2 are located on the same straight line A (shown in FIG. 2) extending in the front-rear direction of the vehicle. The front bush B1 and the rear bush B2 are shown only in FIG.

The arm body 1A includes an upper member 10, a lower member 20, a front bush mounting cylinder 31, and a rear bush mounting cylinder 32. The upper member 10, the lower member 20, the front bush mounting cylinder 31 and the rear bush mounting cylinder 32 are made of, for example, a steel plate or the like. The front bush mounting cylinder 31 is formed so as to surround the bush body B11 of the front bush B1, and the bush body B11 is fixed to the inner surface of the front bush mounting cylinder 31. The front bush mounting cylinder portion 31 may be a member that forms a part of the front bush B1.

The rear bush mounting cylinder 32 is formed so as to surround the bush body B21 of the rear bush B2, and the bush body B21 is fixed to the inner surface of the rear bush mounting cylinder 32. The rear bush mounting cylinder portion 32 may be a member that constitutes a part of the rear bush B2.

The ball joint 40 shown in FIG. 8 is a component of the suspension arm 1. In the description of this embodiment, the suspension arm 1 provided on the left side of the automobile will be described, but the suspension arm (not shown) provided on the right side can be configured symmetrically with the suspension arm 1 provided on the left side.

The suspension arm 1 has two branches in the front-rear direction on the inside in the vehicle width direction. The front bush mounting cylinder 31 and the rear bush mounting cylinder 32 are provided inside the suspension arm 1 in the vehicle width direction. On the other hand, the suspension arm 1 is provided on the outer side in the vehicle width direction, and only one ball joint 40 is provided on the outer side in the vehicle width direction of the suspension arm 1. In each figure, the "outside" means the outside in the vehicle width direction, and the "inside" means the inside in the vehicle width direction. Further, "front" means the front side of the vehicle, and "rear" means the rear side of the vehicle.

As shown in FIG. 4, when the suspension arm 1 is viewed from the outside in the vehicle width direction, the axis X (the axis at the time of neutrality) of the ball joint 40 is inclined with respect to the axes (straight line A) of the bushes B1 and B2. Bush B1, B2 and ball joint 40 are arranged. That is, the axes of the bushes B1 and B2 are located on the straight line A as shown in FIG. 2, whereas the axes of the ball joint 40 extend in the vertical direction as shown by the straight line X in FIG. There is. As shown in FIG. 4, when the suspension arm 1 is viewed from the outside in the vehicle width direction, the straight line A indicating the axes of the bushes B1 and B2 and the straight line X indicating the axes of the ball joint 40 are not orthogonal to each other and are straight lines. The straight line X is inclined with respect to A. This is to improve the steering stability of the vehicle.

(Structure of upper member 10)
As shown in FIG. 6, the upper member 10 is formed by press-molding a plate material, has an upper bulging portion 11 formed so as to bulge upward and open downward, and has a suspension arm. It is a member constituting the upper side of 1. The upper bulging portion 11 is formed continuously from the inside to the outside of the upper member 10 in the vehicle width direction. As shown in FIG. 3, the upper bulging portion 11 is formed so that the amount of bulging upward increases as it approaches the inner end in the vehicle width direction. Therefore, the vertical dimension of the upper member 10 is determined. It becomes longer as it approaches the inner end in the vehicle width direction. Further, the vertical dimension of the upper member 10 on the outer side in the vehicle width direction is set shorter than the vertical dimension of the portion of the upper member 10 branching back and forth on the inner side in the vehicle width direction. Further, as shown in FIG. 2, the front-rear direction dimension of each of the front-rear branching portions of the upper member 10 on the inner side in the vehicle width direction is shorter than the front-rear direction dimension on the outer side in the vehicle width direction of the upper member 10. It is set.

As shown in FIG. 6, a substantially circular upper through hole 10a that penetrates the upper member 10 in the vertical direction is formed on the outer side of the upper member 10 in the vehicle width direction. As shown in FIG. 8, the peripheral edge of the upper through hole 10a of the upper member 10 is subjected to a cylindrical burring process that protrudes downward, and an annular upper ball joint press-fitting portion 12 into which the ball joint 40 is press-fitted. Is formed. Since burring is a well-known processing method, detailed description thereof will be omitted, but a rising portion and a flange portion are integrally formed on the peripheral edge of the upper through hole 10a by using a mold or the like possessed by the burring machine. It is a processing method to be performed.

As shown in FIG. 6, the front edge portion of the upper member 10 is provided with an upper front edge plate portion 10b that projects downward and continuously extends in the vehicle width direction. Further, the trailing edge portion of the upper member 10 is provided with an upper trailing edge plate portion 10c that projects downward and continuously extends in the vehicle width direction. Further, an upper inner edge plate portion 10d that protrudes downward and continuously extends from the front side to the rear side is provided on the inner edge portion in the vehicle width direction, which is a portion branched into two of the upper member 10.

The upper front edge plate portion 10b extends continuously in the vehicle width direction along the front edge portion of the upper member 10, but is not provided on the outer edge portion of the upper member 10 in the vehicle width direction. The upper trailing edge plate portion 10c extends continuously in the vehicle width direction along the trailing edge portion of the upper member 10, but is not provided on the outer edge portion of the upper member 10 in the vehicle width direction. As a result, the outer portion in the vehicle width direction of the arm body 1A with respect to the upper ball joint press-fitting portion 12 is opened toward the outer side in the vehicle width direction.

As shown in FIG. 6 and the like, an upper annular flat plate portion 13 extending in an annular shape surrounding the upper ball joint press-fitting portion 12 is formed around the upper ball joint press-fitting portion 12 in the upper member 10. As shown in FIG. 8, the upper annular flat plate portion 13 extends in a direction orthogonal to the axis of the upper ball joint press-fitting portion 12 (corresponding to the axis of the ball joint 40). The upper annular flat plate portion 13 is located below the peripheral portion (the portion that bulges upward) of the upper annular flat plate portion 13 in the upper member 10. By positioning the upper annular flat plate portion 13 at the bottom, the portion of the arm body 1A that supports the ball joint 40 becomes thin.

(Structure of lower member 20)
The lower member 20 has a lower bulging portion 21 formed so as to bulge downward and open upward, and is a member constituting the lower side of the suspension arm 1. The suspension arm 1 is formed by joining the upper member 10 and the lower member 20 in a state where the open portion of the upper bulge 11 of the upper member 10 and the open portion of the lower bulge 21 of the lower member 20 are combined. Has been done.

The lower bulging portion 21 is formed continuously from the inside to the outside of the lower member 20 in the vehicle width direction. As shown in FIG. 3, the lower bulging portion 21 is formed so that the amount of bulging downward increases as it approaches the inner end in the vehicle width direction, and thus the vertical dimension of the lower member 20. Is longer as it approaches the inner end in the vehicle width direction. Further, the vertical dimension of the lower member 20 on the outer side in the vehicle width direction is set shorter than the vertical dimension of the portion of the lower member 20 branching back and forth on the inner side in the vehicle width direction. Further, the front-rear direction dimension of the portion of the lower member 20 that is branched in the front-rear direction on the inner side in the vehicle width direction is set shorter than the front-rear direction dimension on the outer side in the vehicle width direction of the lower member 20.

As shown in FIG. 7, a substantially circular lower through hole 20a that penetrates the lower member 20 in the vertical direction is formed on the outer side of the lower member 20 in the vehicle width direction. As shown in FIG. 8, the peripheral edge of the lower through hole 20a of the lower member 20 is subjected to a cylindrical burring process that protrudes upward corresponding to the upper ball joint press-fitting portion 12, and the ball joint 40 is formed. An annular lower ball joint press-fitting portion 22 is formed.

As shown in FIG. 7, the front edge portion of the lower member 20 is provided with a lower front edge plate portion 20b that projects downward and continuously extends in the vehicle width direction. Further, the trailing edge portion of the lower member 20 is provided with a lower trailing edge plate portion 20c that projects downward and continuously extends in the vehicle width direction. Further, a lower inner edge plate portion 20d that protrudes downward and continuously extends from the front side to the rear side is provided on the inner edge portion in the vehicle width direction, which is a portion branched into two of the lower member 20.

The lower front edge plate portion 20b extends continuously in the vehicle width direction along the front edge portion of the lower member 20, but is not provided on the outer edge portion of the lower member 20 in the vehicle width direction. .. The lower trailing edge plate portion 20c extends continuously in the vehicle width direction along the trailing edge portion of the lower member 20, but is not provided on the outer edge portion of the lower member 20 in the vehicle width direction. .. As a result, the portion outside the lower ball joint press-fitting portion 22 in the arm body 1A in the vehicle width direction is opened toward the outside in the vehicle width direction.

As shown in FIG. 8, a lower annular flat plate portion 23 extending in an annular shape surrounding the lower ball joint press-fitting portion 22 is formed around the lower ball joint press-fitting portion 22 in the lower member 20. The lower annular flat plate portion 23 extends in a direction orthogonal to the axis of the lower ball joint press-fitting portion 22, and is substantially parallel to the upper annular flat plate portion 13. The lower annular flat plate portion 23 is located above the peripheral portion (the portion that bulges downward) of the lower annular flat plate portion 23 in the lower member 20. By positioning the lower annular flat plate portion 23 upward, the portion of the arm body 1A that supports the ball joint 40 becomes thin.

(Joining the upper member and the lower member)
As shown in FIGS. 4 and 8, the upper front edge plate portion is in a state where the front surface of the lower front edge plate portion 20b of the lower member 20 is overlapped with the rear surface of the upper front edge plate portion 10b of the upper member 10. 10b and the lower leading edge plate portion 20b are welded. Further, the upper trailing edge plate portion 10c and the lower trailing edge plate portion are overlapped with the rear surface of the lower trailing edge plate portion 20c of the lower member 20 on the front surface of the upper trailing edge plate portion 10c of the upper member 10. 20c is welded. Further, it is located on the surface located inside the arm body 1A in the upper inner edge plate portion 10d of the upper member 10 shown in FIG. 6 and outside the arm body 1A in the lower inner edge plate portion 20d of the lower member 20 shown in FIG. The upper inner edge plate portion 10d and the lower inner edge plate portion 20d are welded in a state where the surfaces to be formed are overlapped.

(Detailed structure of the suspension arm 1 on the outside in the vehicle width direction)
As shown in FIG. 8, the center line of the upper ball joint press-fitting portion 12 of the upper member 10 and the center line of the lower ball joint press-fitting portion 22 of the lower member 20 are located on a straight line X extending in the vertical direction. It has become like. Further, the diameter of the upper ball joint press-fitting portion 12 and the diameter of the lower ball joint press-fitting portion 22 are set to be equal. The rotation center C of the ball joint 40 is located on the straight line X.

The vertical dimension of the upper ball joint press-fitting portion 12 and the vertical dimension of the lower ball joint press-fitting portion 22 are set to be equal. The lower end of the upper ball joint press-fitting portion 12 and the upper end of the lower ball joint press-fitting portion 22 are arranged with a gap in the vertical direction. The lower end of the upper ball joint press-fitting portion 12 and the upper end of the lower ball joint press-fitting portion 22 may be brought into contact with each other in the vertical direction.

The outer portion of the suspension arm 1 in the vehicle width direction with respect to the upper ball joint press-fitting portion 12 and the lower ball joint press-fitting portion 22 is open toward the outside in the vehicle width direction. The outer edge portion of the upper member 10 in the vehicle width direction extends in an arc shape along the peripheral edge portion of the upper ball joint press-fitting portion 12, and a vertical flange, a vertical plate portion, and a vertical wall portion are formed on this edge portion. Not. The edge portion of the upper member 10 can also be formed in an arc shape along the peripheral edge portion of the upper through hole 10a.

Further, the outer edge portion of the lower member 20 in the vehicle width direction extends in an arc shape along the peripheral edge portion of the lower ball joint press-fitting portion 22, and this edge portion also has a vertical flange, a vertical plate portion, and a vertical wall. The part is not formed. The edge portion of the lower member 20 can also be formed in an arc shape along the peripheral edge portion of the lower through hole 20a. Since the vertical plate portion and the like are not formed on the outer edges of the upper member 10 and the lower member 20 in the vehicle width direction, there is a gap between the upper member 10 and the vehicle body side parts (peripheral parts) arranged around the suspension arm 1. It will be possible to secure a wide range.

(Structure of bush mounting cylinder)
The front bush mounting cylinder portion 31 is arranged so that the center line extends in the front-rear direction of the vehicle so as to be sandwiched between the front extension plate portion 10e of the upper member 10 and the front extension plate portion 20e of the lower member 20. It is fixed to the arm body 1A. The outer peripheral surface of the front bush mounting cylinder portion 31 is welded to the front extending plate portion 10e and the front extending plate portion 20e. Further, the rear bush mounting cylinder portion 32 is arranged so that the center line extends in the front-rear direction of the vehicle, and includes the rear extension plate portion 10f of the upper member 10 and the rear extension plate portion 20f of the lower member 20. It is fixed to the arm body 1A so as to be sandwiched by. The outer peripheral surface of the rear bush mounting cylinder portion 32 is welded to the rear extending plate portion 10f and the rear extending plate portion 20f.

(Shape of suspension arm 1)
The center C of the ball joint 40 press-fitted into the upper ball joint press-fitting portion 12 and the lower ball joint press-fitting portion 22 (shown in FIGS. 2 and 8) and the center D of the front bush mounting cylinder 31 (shown in FIG. 2). When a virtual plane B (shown in FIG. 4) passing through the center E (shown in FIG. 2) of the rear bush mounting cylinder 32 is set, the upper member 10 and the lower member 20 are press-fitted into the upper ball joint. Except for the portion 12, the lower ball joint press-fitting portion 22, and the peripheral portions of the both press-fitting portions 12, 22, the shape is substantially symmetrical with the virtual plane B as a symmetrical plane.

That is, as shown in FIG. 8, the center of the ball joint 40 is the rotation center C of the ball joint 40, and is located on the straight line X at the center of the suspension arm 1 in the vertical direction of the outer portion in the vehicle width direction. .. The center D of the front bush mounting cylinder 31 is located at the center of the front bush mounting cylinder 31 in the longitudinal direction on the straight line A. Further, the center E of the rear bush mounting cylinder 32 is located at the center of the rear bush mounting cylinder 32 in the longitudinal direction on the straight line A. The virtual plane B is a plane determined by points C, D, and E. Points C, D, and E are reference points at the time of design and are also called hard points (H / P). By making the virtual plane B passing through the three hard points a symmetrical plane and making the cross section substantially symmetrical in the vertical direction, it is possible to minimize the cross-sectional shape while ensuring the rigidity of the suspension arm 1. Since the upper plate material 10 and the lower plate material 20 are overlapped and welded, the cross section does not have a strictly vertically symmetrical shape, but the difference in shape to that extent has an extremely small effect on strength and rigidity. , Almost no problem. That is, if the cross-sectional shape is substantially symmetrical in the vertical direction with the virtual plane B as the plane of symmetry, the rigidity and strength of the suspension arm 1 can be sufficiently increased even if the cross-sectional shape is reduced.

(Action and effect of the embodiment)
As described above, according to this embodiment, when the suspension arm 1 is viewed from the vehicle width direction, the axis of the ball joint 40 is inclined with respect to the axes of the bushes B1 and B2, so that the ball joint axis is formed. The layout is not orthogonal to the bush axis, and it is possible to improve steering stability, for example.

Then, since the hollow arm body 1A is formed by the upper member 10 and the lower member 20 formed by molding the plate material, the suspension arm 1 is highly rigid and lightweight. Since the ball joint 40 is attached to the arm body 1A by being press-fitted into the upper ball joint press-fitting portion 12 of the upper member 10 and the lower ball joint press-fitting portion 22 of the lower member 20, the upper member 10 and the lower member 20 It will be supported by both, and high support rigidity can be obtained.

Since the outer portion in the vehicle width direction is open toward the outer side in the vehicle width direction from the upper ball joint press-fitting portion 12 and the lower ball joint press-fitting portion 22 of the arm body 1A, the vertical flange on the outer side in the vehicle width direction disappears, and the periphery It is possible to secure a wide gap between the parts.

The above embodiments are merely exemplary in all respects and should not be construed in a limited way. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

As described above, the vehicle suspension arm according to the present invention can be used as, for example, an upper arm of a double wishbone suspension device.

1 Suspension arm 1A Arm body 10 Upper member 11 Upper bulging part 12 Upper ball joint press-fitting part 13 Upper annular flat plate part 20 Lower member 21 Lower bulging part 22 Lower ball joint press-fitting part 23 Lower annular flat plate part 31 Front side Bush mounting cylinder 32 Rear bush mounting cylinder 40 Ball joint B Virtual plane B1 Front bush B2 Rear bush

Claims (7)

With the arm body
A tubular bush that is attached to the inside of the arm body in the vehicle width direction and has an axis extending in the vehicle front-rear direction.
A ball joint attached to the outside of the arm body in the vehicle width direction and having an axis extending in the vertical direction is provided.
In a vehicle suspension arm that is swingably supported in the vertical direction with respect to the vehicle body by the bush.
The bush and the ball joint are arranged so that the axis of the ball joint is inclined with respect to the axis of the bush when viewed from the vehicle width direction.
A plate material formed so as to bulge upward and open downward, and an upper member constituting the upper side of the arm body and
It is made of a plate material that is formed so as to bulge downward and open upward, and is joined to the lower members constituting the lower side of the arm body in a state where the open portions are aligned with each other.
A cylindrical burring process is applied to the outer side of the upper member in the vehicle width direction so as to project downward to form an upper ball joint press-fitting portion into which the ball joint is press-fitted.
On the outer side of the lower member in the vehicle width direction, a cylindrical burring process is performed so as to project upward corresponding to the upper ball joint press-fitting portion, and a lower ball joint press-fitting portion into which the ball joint is press-fitted is formed. ,
A suspension arm for a vehicle, wherein a portion outside the upper ball joint press-fitting portion and the lower ball joint press-fitting portion in the arm body in the vehicle width direction is opened toward the outside in the vehicle width direction. In the vehicle suspension arm according to claim 1.
Inside the arm body in the vehicle width direction, a front bush mounting cylinder portion and a rear bush mounting cylinder portion to which the bushes are mounted are provided at intervals in the vehicle front-rear direction.
A virtual plane passing through the center of the ball joint press-fitted into the upper ball joint press-fitting portion and the lower ball joint press-fitting portion, the center of the front bush mounting cylinder portion, and the center of the rear bush mounting cylinder portion is set. Then, the upper member and the lower member are substantially symmetrical with the virtual plane as a symmetrical plane, except for the upper ball joint press-fitting portion, the lower ball joint press-fitting portion, and the peripheral portions of both press-fitting portions. A vehicle suspension arm characterized by having a symmetrical shape. In the vehicle suspension arm according to claim 1 or 2.
An upper annular flat plate portion extending in an annular shape is formed around the upper ball joint press-fitting portion.
The suspension arm for a vehicle, wherein the upper annular flat plate portion is located below a portion of the upper member that is lower than the peripheral portion of the upper annular flat plate portion. The vehicle suspension arm according to any one of claims 1 to 3.
A lower annular flat plate portion extending in an annular shape is formed around the lower ball joint press-fitting portion.
A vehicle suspension arm, wherein the lower annular flat plate portion is located above a portion of the lower member around the lower annular flat plate portion. In the vehicle suspension arm according to any one of claims 1 to 4.
The outer edge portion of the upper member in the vehicle width direction extends in an arc shape along the peripheral edge portion of the upper ball joint press-fitting portion.
A vehicle suspension arm, wherein an outer edge portion of the lower member in the vehicle width direction extends in an arc shape along a peripheral edge portion of the lower ball joint press-fitting portion. The vehicle suspension arm according to any one of claims 1 to 5.
The upper member is formed so that the amount of bulge upward increases as it approaches the inner end in the vehicle width direction.
The lower member is a suspension arm for a vehicle, characterized in that the lower member is formed so that the amount of bulge downward increases as it approaches the inner end in the vehicle width direction. The vehicle suspension arm according to any one of claims 1 to 6.
A vehicle suspension arm, characterized in that a lower end portion of the upper ball joint press-fitting portion and an upper end portion of the lower ball joint press-fitting portion are arranged with a gap in the vertical direction.

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