JPH09193637A - Three-link type rear suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the fall of a trailing arm caused by the reaction of a shock absorber. SOLUTION: A three-link type rear suspension device is provided with a rear axle housing 2 supporting a rear wheel 1 rotatably, a trailing arm 3 with its front end part supported in a vertically oscillating state on a body through a rubber bush 6 and with its rear end part connected in two longitudinal places to the rear axle housing 2 through rubber bushes 9, 10, and a shock absorber for supporting the rear axle housing in a cushioned state to the body. The trailing arm 3 with its front end supporting part offset to the outside in a vehicle cross direction from its rear connecting part has an extension part 3d extended backward from the connecting part to the rear axle housing 2, and a lower end part 4a of the shock absorber is connected to the extension part 3d. The connection center D of the extension part 3d and shock absorber is disposed in an area S surrounded by straight lines connecting the front end support point A of the trailing arm and connecting points B, C in two longitudinal places to the rear axle housing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-link rear suspension device, and more particularly to a shock absorber mounting structure.

[0002]

2. Description of the Related Art Generally, a three-link type rear suspension device includes a rear axle housing that rotatably supports rear wheels, a front end portion that is swingably supported by a vehicle body, and a rear end portion that is connected to the rear axle housing. The trailing arm and the shock absorber that cushions and supports the rear axle housing with respect to the vehicle body.

The front end of the trailing arm is pivotally supported on the vehicle body via a rubber bush, and the rear end is rigidly connected to the rear axle housing. Therefore, a relative displacement occurs between the rear axle housing and the trailing arm due to an input from the rear wheel, and a high stress acts on the joint between them. As a result, the fatigue strength of the joint decreases,
There is a problem with durability.

In order to solve such a problem, the actual development 6
As disclosed in Japanese Patent Laid-Open No. 3-150806, a trailing arm whose rear end is connected to a rear axle housing via a rubber bush is proposed. In this case, the relative twist between the rear axle housing and the trailing arm can be absorbed by the rubber bush, so damage to the joint can be prevented. In particular, by arranging the connecting parts at two positions in front and rear, it is possible to effectively absorb the drive reaction force (for FR vehicle) and the brake reaction force (for FF vehicle) from the wheels, and prevent the rear axle housing from twisting. There are features.

In the case of the conventional rear suspension device described above, the lower end portion of the shock absorber is connected to the rear axle housing via a bracket or the like, but in other types of suspension devices, the rear end portion of the trailing arm is used. There is one in which the shock absorber is connected to the rear axle housing to the rear and the lower end of the shock absorber is connected to this extension (Japanese Utility Model Laid-Open No. 62-16010). In addition, in order to prevent interference between the trailing arm and parts (eg, fuel tank) arranged under the vehicle body and increase the degree of freedom of arrangement, move the trailing arm from the front end to the outside in the vehicle width direction from the rear end. It may be bent so as to be offset.

[0006]

As described above, the rear end portion of the trailing arm is extended rearward from the connecting portion with the rear axle housing, and the lower end portion of the shock absorber is connected to this extended portion, and the trailing arm is also connected. In a three-link rear suspension device in which the front side is bent so that it is offset outward in the vehicle width direction, when the reaction force of the shock absorber acts on the extension of the trailing arm when the wheels bounce, the trailing arm Since it is bent in the width direction, there is a problem that the trailing arm may fall (roll). When the trailing arm falls down, the designed spring constant cannot be obtained, which causes problems such as deterioration of riding comfort and maneuverability, interference with the bracket, and fatigue of the rubber bush.

Therefore, an object of the present invention is to connect the lower end of the shock absorber to the rear end extension of the trailing arm and to bend the trailing arm so that its front end is offset outward in the vehicle width direction. It is an object of the present invention to provide a structure capable of effectively preventing a trailing arm from collapsing due to a reaction force of a shock absorber in a 3-link type rear suspension device.

[0008]

In order to achieve the above object, the present invention provides a rear axle housing for rotatably supporting a rear wheel, a front end portion extending in the front-rear direction of a vehicle body, and a rubber bush for the vehicle body. Supported so that it can swing up and down,
A three-link rear having a trailing arm whose rear end is connected to the rear axle housing at two front and rear positions via rubber bushes, and a shock absorber that extends in the vertical direction and cushions and supports the rear axle housing with respect to the vehicle body. In the suspension device, a front end support portion of the trailing arm is offset outward in the vehicle width direction from a rear connecting portion, and the trailing arm is formed with an extension portion extending rearward from a connecting portion with the rear axle housing. The lower end portion of the shock absorber is connected to the extension portion, and the center of connection between the extension portion and the shock absorber is within a region surrounded by a straight line connecting the front end support point of the trailing arm and the two connection points before and after the rear axle housing. It is arranged in.

When the rear wheel bounces, the reaction force of the shock absorber acts downward on the extension of the trailing arm. Therefore, the trailing arm tends to rotate about the roll axis. Since the roll shaft is located in the area surrounded by the straight line connecting the front end support point of the trailing arm and the two connecting points in the front and rear with respect to the rear axle housing, the center of connection between the extension and the shock absorber is located in this area. By arranging it, the center of connection between the extension and the shock absorber can be arranged near the roll axis,
The tilting moment is extremely small. Therefore, the trailing arm can be prevented from falling.

In the present invention, since the front support portion of the trailing arm is offset outward of the rear connecting portion in the vehicle width direction, the trailing arm interferes with a member (for example, a fuel tank) arranged under the vehicle body. Can be prevented, and the flexibility of the shape and arrangement of the members can be increased.

Further, since the rear end portion of the trailing arm is connected to the rear axle housing by two rubber bushes at the front and rear, driving reaction force from wheels (in the case of FR vehicle) and brake reaction force (in the case of FF vehicle). Case) can be effectively absorbed and twisting of the rear axle housing can be prevented.

When the connecting point between the trailing arm and the rear axle housing is arranged in front of and behind the axle center, the shock is shocked on the straight line connecting the front end support point of the trailing arm and the midpoint of the front and rear connecting points. It is desirable to locate the connection point between the lower end of the absorber and the extension of the trailing arm. In this case, not only the tilting moment of the trailing arm can be reduced to almost zero, but also the twist of the rear axle housing can be effectively reduced.

[0013]

1 to 3 show an embodiment in which a 3-link type rear suspension device according to the present invention is applied to an FR (front engine / rear drive) vehicle. In the figure, 1 is a rear wheel, 2 is a rear axle housing that rotatably supports the rear wheel 1, 3 is a trailing arm extending in the vehicle longitudinal direction, 4 is a shock absorber, and 5 is a suspension spring.

The trailing arm 3 is bent so that its front side is offset from the rear side by a dimension W outward in the vehicle width direction. Therefore, it is possible to prevent interference between the front end portion of the trailing arm 3 and a component T such as a fuel tank arranged inside the trailing arm 3, and even if the component T has a large width,
It becomes possible to arrange. A hole 3a in the vehicle width direction is formed at the front end of the trailing arm 3.
A rubber bush 6 is attached to a and is attached to a bracket 7 fixed to the vehicle body by a bolt 8 so as to be vertically swingable. Further, two holes 3b, 3c in the vehicle width direction are formed at the rear end of the trailing arm 3 so as to be spaced apart from each other by a predetermined distance L in the front-rear direction. Is mounted and connected to a bracket 11 fixed to the lower side of the rear axle housing 2 by bolts 12 and 13. The bolt 12,
The middle point O of 13 is located on the axis of the axle 14 arranged in the rear axle housing 2.

An extension 3d is formed at the rear end of the trailing arm 3 and extends rearward from the connection with the rear axle housing 2, and the spindle 3 is provided at the tip of the extension 3d.
e is provided so as to project toward the inside of the vehicle body. The lower end 4a of the shock absorber 4 is attached to the rubber bush 1 on the support shaft 3e.
It is connected through 5. The upper end of the shock absorber 4 is connected to the vehicle body via a rubber bush.

The connecting center D between the shock absorber 4 and the extension 3d is the front end support point A of the trailing arm 3.
And the rear axle housing 2 are arranged in a region S (indicated by diagonal lines in FIG. 2) surrounded by a straight line connecting two connecting points B and C on the front and rear sides. Particularly in this embodiment, the connection center D is located on the straight line connecting the front end support point A and the midpoint O of the connection points B and C.

The operation of the three-link rear suspension device having the above structure will be described. When the rear wheel bounces, the reaction force of the shock absorber 4 is applied to the extension 3 of the trailing arm 3.
Acts downward on d. The trailing arm 3 is supported so as to be vertically swingable about its front end as a fulcrum, but since the trailing arm 3 itself is bent toward the inside of the vehicle body at the rear side, the reaction force of the shock absorber 4 causes
The trailing arm 3 tries to fall in either the left or right direction around the roll axis. However, the connection center D between the extension 3d and the shock absorber 4 is within a region S surrounded by a straight line connecting the front end support point A of the trailing arm 3 and the connection points B and C at the two front and rear positions with respect to the rear axle housing 2. Since they are arranged, the connection center D is located near the roll axis, and the tilting moment is extremely small. Therefore, it is possible to prevent the trailing arm 3 from falling down, and it is possible to eliminate problems such as deterioration of riding comfort and controllability, interference with the bracket, and fatigue of the rubber bush. In particular, by arranging the connecting center D on the straight line connecting the front end supporting point A and the midpoint O of the connecting points B and C, the tilting moment of the trailing arm 3 can be made almost zero, and the most desirable characteristic can be obtained. .

Further, since the rear end portion of the trailing arm 3 is connected to the rear axle housing 2 at two front and rear positions by the rubber bushes 9 and 10, the driving reaction force from the wheel 1 (in the case of an FR vehicle) and the brake. Reaction force (FF car)
Is effectively absorbed, and the twisting of the rear axle housing 2 can be prevented.

The present invention is not limited to the above embodiment. For example, the extension 3 of the trailing arm 3
As a connection structure between the d and the lower end portion 4a of the shock absorber 4, a support shaft 3e is projectingly provided on a side surface of the extension portion 3d, and the lower end portion 4a is attached to the support shaft 3e via a rubber bush 15. 3d may be formed in a bifurcated shape, and a shaft that supports the lower end portion 4a of the shock absorber 4 may be bridged and attached to these extended portions. In the embodiment, the trailing arm 3 has a shape in which the front side is bent outward in the vehicle width direction from the rear side, but a straight trailing arm may be used, and the trailing arm 3 is curved in an S shape. Good. The rear suspension device of the present invention is applicable not only to FR type vehicles but also to FF type vehicles.

[0020]

As is apparent from the above description, in the three-link rear suspension device of the present invention, the connection center between the rear extension of the trailing arm and the shock absorber is set at the front end support point of the trailing arm and the rear axle. The trailing arm can be prevented from falling down due to the reaction force of the shock absorber, because the trailing arm is arranged in the area surrounded by the straight line connecting the front and rear connecting points with respect to the housing. Therefore, there are effects such as improvement of riding comfort and maneuverability, prevention of interference with the bracket, and prevention of fatigue of the rubber bush. Further, since the trailing arm can be prevented from falling down only by devising the position of the connecting point of the shock absorber, it is not necessary to add another component, and the structure is simple and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a rear portion of a vehicle equipped with a 3-link rear suspension device according to the present invention.

FIG. 2 is a plan view of a suspension device on the right side of the vehicle body in FIG.

3 is a side view of the suspension device of FIG. 2. FIG.

[Explanation of symbols]

 1 Rear Wheel 2 Rear Axle Housing 3 Trailing Arm 3d Extension 4 Shock Absorber 6, 9, 10, 15 Rubber Bushing A Front End Supporting Point B, C Connection Point with Rear Axle Housing D Connection Center with Shock Absorber

Claims (1)

[Claims] 1. A rear axle housing that rotatably supports a rear wheel, a front axle extending in the vehicle front-rear direction, a front edge of the rear axle being swingably supported by a rubber bush with respect to the vehicle, and a rear edge of the rear axle housing. To a trailing arm connected to the front and rear via rubber bushes,
In a three-link rear suspension device that extends in the vertical direction and includes a shock absorber that cushions and supports the rear axle housing with respect to the vehicle body, the front end support portion of the trailing arm is offset outward from the rear connection portion in the vehicle width direction. The trailing arm is formed with an extension extending rearward from the connection with the rear axle housing, the lower end of the shock absorber is connected to the extension, and the center of connection between the extension and the shock absorber is the trailing arm. A three-link rear suspension device, which is arranged in a region surrounded by a straight line connecting a front end support point of an arm and two connecting points in front of and behind the rear axle housing.