JPH03197216A - Rear suspension device for vehicle - Google Patents

Abstract

PURPOSE:To improve riding comfort and travel stability by forming an upper arm for supporting a wheel support member on a body with two upper and lower sections extended in the lengthwise and widthwise directions of the body, and locating the outer end of a tie rod for rear wheel steering at a level higher than the inner end thereof. CONSTITUTION:A wheel support member 2 for so bearing a wheel 1 as to be freely rotatable is supported on two upper and lower arms 3 and 4 laid at a vertical interval, and a lower arm 5 laid under the aforesaid arms 3 and 4 in such a way as to be capable of free oscillation relative to a body. In this case, the upper arm 3 is laid in the lengthwise direction of the body and the lower arm 4 in the widthwise direction, respectively. Also, the outer end 9 of a tie rod for rear wheel steering is pivotally connected to the axis arm 2b of the wheel support member 2 at a position backward of a kingpin axis formed by connecting each pivotal joint parts 3a to 5a of all the aforesaid arms 3 to 5 at the side of the wheel support member 2. Furthermore, the outer end 9a of the aforesaid tie rod 9 is positioned higher than the inner end.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle rear suspension device, particularly a double wishbone type vehicle rear suspension in which a lower arm and a plurality of upper arms support wheels in a swingable manner. Regarding equipment.

[Prior art]

Generally, as an independent suspension system for vehicles,
The double wishbone type vehicle suspension system, in which the wheels are swingably supported by a lower arm and multiple upper arms, has the advantage of being able to relatively minimize camber changes and scuff changes caused by the scoot at the time of starting and the vertical movement of the wheels. .

On the other hand, there is a problem in that the longitudinal impact load acting on the wheels tends to affect the vehicle body.In order to solve this problem, flexible elastic bushings are inserted at the joints of the multiple upper arms to the vehicle body. There is a problem in that the support rigidity of the wheel support member around the axle is reduced, the natural frequency of the wheel support member is reduced, and brake shudder, in which the wheel support member resonates with the wheel etc. during braking, may occur.

In order to solve this problem, the wheel support member is provided with an arm portion extending above the wheel, and two upper arms arranged at an angle on substantially the same plane are pivotably mounted on the upper end of the arm portion. A suspension device in which a lower arm is pivotally attached to the lower part of a wheel support member was proposed, but there was a problem in that the buffering effect of external forces acting around the axle of the wheel support member was insufficient.

In addition, space is required above the wheel to allow the wheel to move up and down, and space is required inside the wheel to place various parts. Since a large space is required, the dimensions and layout of the upper arm are restricted, and the vertical stroke of the wheel is insufficient, resulting in excessive camber changes during severe rocking, and making it difficult to drive at high speed on roads with small curvature. There has been a problem in that the camber rigidity is insufficient during small turns such as when turning, which affects steering stability.

For example, Japanese Patent Laid-Open No. 58-67508 discloses a vehicle suspension device proposed to improve steering stability.
In the vehicle described in the above publication, a wheel support member is provided with an arm portion extending above the wheel, and two upper arms arranged at an angle in substantially the same plane are pivotally attached to the upper end of the arm portion. In a suspension device in which a lower arm and a tie rod are pivotally connected to the lower part of the wheel support, the lower pivot point is conceptually defined as the intersection of the axes of the two upper arms above the lower pivot point formed at the outer end of the lower arm. The aim is to improve steering stability when turning by setting pivot points and forming an instantaneous turning axis that connects both pivot points, and configuring the outer wheels to have negative camber when turning. .

[Problems to be Solved by the Invention] However, in the above conventional suspension device, in order to provide the two upper arms on the same plane,
The constraints on the dimensions and layout of the upper arm are even more severe, and if a flexible elastic bushing is inserted at the pivot point of the upper arm to the vehicle body, the impact received by the upper arm will cause the lower part of the upper arm, which is located at the intersection of the axes of the two upper arms, to There is a problem in that the position of the pivot point may shift, and the original purpose may not be achieved due to this position shift.

An object of the present invention is to solve the above-mentioned problems, improve ride comfort, prevent the occurrence of brake jug, and improve turning performance at the beginning of a turn and steering stability during high-speed turns. It is an object of the present invention to provide a rear suspension device for a vehicle that can be used in a vehicle.

Means for Solving the C4J Problem] In order to achieve the above object, a rear suspension device for a vehicle according to the present invention includes an upper arm and a lower arm that swingably support a wheel support member on a vehicle body. consists of an upper upper arm and a lower upper arm spaced apart in the vertical direction of the vehicle body,
The rear end of the upper upper arm extending in the longitudinal direction of the vehicle body is pivotally connected to the upper end of the wheel support member, and the front end thereof is pivotally connected to the upper position on the vehicle body side, and the outer end of the lower upper arm extending in the width direction of the vehicle body is attached to the upper end of the wheel support member. In the middle of the wheel support member,
The inner end is pivoted to the middle position on the vehicle body side.

Furthermore, the inner end of the tie rod for rear wheel steering is connected to the wheel support member at a position rearward of the kingpin shaft connecting the pivot points of the upper and lower arms on the wheel support member side, and the outer end of the tie rod in the vehicle body width direction is connected to the wheel support member. It is arranged so as to be located above the end.

[Operation] In the vehicle rear suspension device of the present invention configured as described above, since the upper upper arm can effectively restrict the displacement of the wheel support member in the vehicle body longitudinal direction, the vehicle body side pivot of the upper upper arm can be effectively restricted. By adopting a flexible elastic bunche at the landing point, it is possible to increase compliance in the longitudinal direction of the wheel and improve ride comfort, while also effectively reducing and cushioning the natural frequency around the axle of the wheel support member. This can prevent brake shudder from occurring.

The lower upper arm extending in the width direction of the vehicle body is pivotally connected to the middle part of the wheel support member below the upper brim arm.
There is a relatively high degree of freedom in layout, a sufficient length can be obtained, camber changes during rocking can be reduced, and good steering stability can be obtained.

In addition, the upper and lower arms are placed at different height positions,
Since the upper upper arm extends in the longitudinal direction of the vehicle body, it does not require space above the inner side of the wheels, increasing the degree of freedom in layout.

Furthermore, the outer end of the rear wheel steering tie rod is connected to the wheel support member behind the kingpin shaft, and the tie rod is arranged so that the outer end in the vehicle width direction is located above the inner end. Therefore, when a wheel bumps during a turn, the tie rod swings around its inner end, and its outer end moves inward while rising, pulling the connection part of the wheel support member inward and moving it toward the end of the vehicle. This gives a tendency to toe-out, so that the outer rear wheel toes out at the beginning of a turn to improve retrospective performance, and when turning at high speed, the upper arm is retracted to gradually increase the toe-in cover of the rear wheel to stabilize the turn. This is to ensure the sex.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

In FIGS. 1 and 2, the wheel support member 2 that rotatably supports the wheel 1 includes two upper and lower arms 3.4 spaced apart in the vertical direction of the vehicle body, and a lower arm 5 disposed below the upper arms 3.4. It is supported so that it can swing up and down relative to the vehicle body.

The wheel support member 2 has an arm portion 2a extending above the wheel 1, and a rear end portion 3a of an upper upper arm 3 extending forward in the longitudinal direction of the vehicle body is pivotally connected to the upper end of the arm portion 2a.
The front end portion 3b of the upper upper arm 3 is pivotally mounted at an upper height position of the vehicle body.

On the other hand, the lower upper arm 4 extends substantially in the width direction of the vehicle body, and its outer end 4a is pivotally connected to a position in the middle of the wheel support member 2, and its inner end 4b is located at a height position in the middle of the vehicle body. It is pivotally connected to a bracket 71 that extends in the width direction of the vehicle body and is provided on the upper part of the cross-section fence 7.

Further, the lower arm 5 extends in the vehicle width direction, and its outer end 5a is pivotally connected to the lower part of the wheel support member 2, and its inner end 5b is attached to the rear suspension cross member 7 at a lower height position of the vehicle body. The outer end of the arm member 11 is connected to the lower arm 5 at a predetermined angle, and the inner end is pivotally connected to the lower part of the rear suspension cross member 7. It is worn.

A lower end of a damper 6 is pivotally attached to a position near an outer end 58 of the lower arm 5 so as to be freely swingable, and an upper end of the damper 6 is connected to the vehicle body.

At a position behind the kingpin axis formed by connecting the pivot points of the pivot points 3a+4a, 5a of the two wheel support members of the upper and lower upper arms 3, 4 and the lower arm 5,
The outer end 9a of the rear wheel steering tie rod 9 is connected to the wheel support member 2.
The inner end 9b of the tie rod 9 is connected to the steering gear 10, and the outer end 9a is connected to the inner end. The tie rod 9 is disposed so as to be located below the portion 9b and inclined upward by an angle θ relative to a horizontal line passing through the inner end portion 9b (see CL).

In addition, in the figure, 8 is a vehicle body frame, and 12 is a stabilizer.

According to the above-mentioned configuration, by extending the arm portion 2a of the wheel support member 2 upward, the upper upper arm 3 can be moved from the pivot point of the outer end portion 5a of the lower arm 5, which is relatively rigidly connected to the vehicle body in the longitudinal direction. By increasing the distance between the rear end portion 3a and the pivot point, increasing the lever ratio to the axle of the wheel 1, and interposing a flexible elastic bushing on the front end portion 3b of the upper upper arm 3, the wheel 1 It improves the longitudinal compliance characteristics of the vehicle, absorbs shocks softly, and improves ride comfort.

Further, during braking, the external force around the axle acting on the wheel support member 2 is applied in the compression direction of the flexible elastic bushing of the front end portion 3b of the upper upper arm 3, thereby reducing and buffering the natural frequency of the wheel support member 2. This prevents the occurrence of goo during play pheasants.

On the other hand, by arranging the lower upper arm 4 below the upper upper arm 3, the rear suspension cross member 7
There is a relatively high degree of freedom in layout in the direction along the This eliminates canvas changes and provides good steering stability.

Furthermore, since the upper and lower upper arms 3.4 are arranged at different height positions, no space is required inside and above the wheels 1, and the degree of freedom in layout is increased.

Further, the outer end 9a of the rear wheel steering quirod 9 is pivotally connected to the wheel support member 2 behind the kingpin shaft, and the tie rod 9 is arranged such that the outer end 9a is located above the inner end 9b. is arranged so as to be inclined downward by an angle θ from the horizontal line passing through the inner end portion 9b, so that when the outer rear wheel 1 humps during a turn, the tie rod 9 is inclined upward by an angle θ at a position CL. When the vehicle approaches the horizontal line HL, the position of the outer end 9a moves inward in the vehicle width direction, pulling the shaft arm 2b inward, making the wheels 1 tend to toe out, improving turning performance at the initial stage of turning.

When the hump amount increases during high-speed turns, the upper upper arm 3 disposed in the front direction of the vehicle body pulls the upper end of the arm portion 2a of the wheel support member 2 forward, so that the kingpin shaft is drawn inward and approaches the vertical direction. This makes it easier to steer, and also gives the wheels 1 a tendency to toe-in, reducing the amount of toe-out at the beginning of a turn and ensuring stability during turning (see Fig. 3).

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

Since the upper upper arm can effectively restrict the displacement of the wheel support member in the longitudinal direction of the vehicle body, by adopting a flexible elastic bushing at the pivot point on the vehicle body side of the upper upper arm, it is possible to ride with a large degree of compliance in the longitudinal direction of the wheel. Not only can comfort be improved, but also the natural frequency of the wheel support member around the axle can be effectively reduced and buffered, thereby preventing the occurrence of brake jug.

The lower upper arm, which extends in the width direction of the vehicle body, is pivotally connected to the middle of the wheel support member below the upper upper arm, so there is a relatively high degree of freedom in layout, and the length can be set to a sufficient length. It is possible to reduce camber change and obtain good steering stability.

In addition, the upper and lower arms are placed at different height positions,
Since the upper upper arm extends in the longitudinal direction of the vehicle body, it does not require space above the inner side of the wheels, increasing the degree of freedom in layout.

Furthermore, by connecting the outer end of the rear wheel steering tie rod to the wheel support member behind the kingpin axis and above the inner end of the tie rod, the wheels can be rotated when turning. When a bump occurs, the tie rod moves tg centering on the inner end, and when the outer end rises, it presses the connection part of the wheel support member outward, and the kingpin shaft, which is tilted forward and downward, is aligned with the vertical line. Since the wheels are brought closer to each other, the wheels tend to toe out at the beginning of a turn, and turning performance at the beginning of a turn can be improved.

Additionally, when turning at high speed, when the hump amount increases, the upper upper arm placed in the front direction of the vehicle body pulls the upper end of the arm portion of the wheel support member forward, so the kingpin shaft is pulled inward and approaches the vertical direction. become,
In addition to being in a state where it is easy to steer, it is possible to give the wheels a tendency to toe-in, reduce toe-out (l) at the beginning of a turn, and maintain stability during a turn by 6M.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, and FIG. 1 is a front view from the rear of a rear wheel suspension device to which the present invention is applied;
FIG. 2 is a plan view, and FIG. 3 is a graph showing toe characteristics. ■...Wheel, 2...Wheel support member, 3...Upper upper arm, 4...Lower upper arm, 5...Lower arm, 9...
・Tie rod for rear wheel steering.

Claims (1)

[Claims] (1) In a suspension device equipped with an upper arm and a lower arm that swingably support a wheel support member on the vehicle body, the upper arm is composed of an upper upper arm and a lower upper arm spaced apart from each other in the vertical direction of the vehicle body, and the upper arm is connected to the vehicle body. Lower upper arms are arranged in the vehicle width direction in the front-rear direction, and a rear wheel steering tie rod is connected to the wheel support member behind the king pin shaft, such that the outer end of the tie rod in the vehicle width direction is closer to the inner end. A rear suspension device for a vehicle, characterized in that the rear suspension device is arranged such that the rear suspension device is located above the vehicle.