JPH0885316A - Rear wheel suspension device - Google Patents

Abstract

PURPOSE: To provide a rear wheel suspension device which improves the stability of a vehicle during braking, and can lower the longitudinal rigidity of a suspension arm. CONSTITUTION: A lower arm 2 is connected to the lower domain of an axle 1 through a pair of front and rear bushes. The lower arm 2 extends inward in the car lateral direction, and is connected to a car body side member through a pair of connecting points lined up longitudinally. The bush 4 being front in the longitudinal direction of the car body between the bushes 3, 4 interposed at each connecting point is an anisotropic bush, which is set up to be low in radial rigidity along an oblique direction being upward toward an outside in the car lateral direction. The upper domain of the axle 4 and the car body side member are mutually osbillatably connected through an upper arm 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel suspension system,
In particular, the present invention relates to a rear wheel suspension system in which a wind-up direction moment during braking is received by an A-type or H-type suspension arm.

[0002]

2. Description of the Related Art As a conventional rear wheel suspension system, for example, JP-A-63-270205 and JP-A-60-4480.
Some of them are disclosed in Japanese Patent No. 6 or the like. JP 63-
As described in Japanese Patent No. 270205, as shown in FIG. 12, H-shaped arms 41 and 42 in which an upper region and a lower region of a wheel support member 40 extend in the vehicle width direction, respectively.
It is connected to the vehicle body side member via and is swingable in the vertical direction.

The lower arm 41 arranged in the lower area, the vehicle body supporting member, and the swing axis of the connecting point are set so as to be inclined so that the front side of the vehicle body faces upward in side view, and the lower arm 41 is arranged in the upper area. The swing axis of the connection point between the upper arm 42 and the vehicle body supporting member is set to be inclined so that the front side of the vehicle body faces inward in the vehicle width direction in plan view. As a result, the toe change in the toe-in direction is given to the input of the longitudinal force input during engine braking to improve the running stability.

Further, the one disclosed in Japanese Utility Model Laid-Open No. 60-44806 is a semi-trailing arm type rear wheel suspension device, which is located on the rear side of the suspension arm (semi-trailing arm) in the longitudinal direction of the vehicle body. The wheel support member is connected, and the front side in the front-rear direction of the vehicle body is connected to the member on the vehicle body side so as to be vertically swingable via two points arranged in the vehicle width direction. Then, an anisotropic bush is adopted as a bush interposed at a connection point outside the vehicle width direction among the connection points to the vehicle body side member, and the anisotropic bush has an axis line oriented in the vehicle width direction. The currant is provided at a position approximately in the front-rear direction of the vehicle body with the moving shaft sandwiched therebetween, and at a position inclined by -10 to 30 degrees with respect to the horizontal plane.

[0005]

However, in the rear wheel suspension device described in Japanese Patent Laid-Open No. 63-270205, the toe angle is defined by the displacement of the H-shaped arm. When the wheel support portion side of the H-shaped arm is pushed rearward by the longitudinal force, the H-shaped arm moves to the position shown in FIG.
As shown in FIG. 3, it is rotationally displaced in a toe-out tendency (FIG.
Inside, displaced from the broken line to the position of the solid line). Therefore, there is a problem that the toe-in effect is reduced.

This problem becomes more prominent as the rigidity of the bush used at the attachment point of the H-shaped arm is decreased in order to reduce the longitudinal rigidity of the suspension arm in order to reduce the harshness. In addition, the above-mentioned actual development 60-44806
In the rear wheel suspension device described in the publication, when a longitudinal force is input to the wheel, the bush provided on the outer side in the vehicle width direction with the curls largely bends, and the suspension arm and the wheel support member rotate and change in the toe-out direction. To do. As a result, there is a problem that the vehicle stability during braking is disturbed.

As described above, particularly in the rear wheel suspension system of the type in which the toe angle of the wheel is directly regulated by the suspension arm having the above-mentioned conventional structure, It is difficult to achieve both the prevention of the toe-out tendency of the wheels with respect to the input to improve the vehicle stability during braking and the reduction of the front-rear rigidity of the suspension arm to improve the riding comfort when riding over bumps. .

In view of the above problems, it is an object of the present invention to provide a rear wheel suspension system capable of improving vehicle stability during braking and lowering longitudinal rigidity of a suspension arm. There is.

[0009]

In order to achieve the above-mentioned object, a rear wheel suspension system according to a first aspect of the present invention has a lower region of a wheel supporting member and a vehicle body side member in a vehicle width direction. Are connected to each other by an H-shaped arm, and the H-shaped arm and the wheel supporting member, and the H-shaped arm and the vehicle body side member are
In a rear wheel suspension device in which two pivot points are lined up in the front-rear direction of a vehicle body and are pivotably connected via a bush whose front-rear direction is the vehicle body, a connection point between the H-shaped arm and a vehicle-body-side member. At least one of the bushes that is
It is characterized in that it is configured by an anisotropic bush in which the rigidity in the radial direction is set to be low along the inclination direction that is directed outward in the vehicle width direction.

In the rear wheel suspension system according to claim 2 of the present invention, the lower region of the wheel support member and the vehicle body side member are
They are connected by an H-shaped arm extending in the vehicle width direction, and the H-shaped arm and the wheel support member, and the H-shaped arm and the vehicle body side member are respectively arranged at two points aligned in the vehicle body front-rear direction. In the rear wheel suspension device which is swingably connected via a bush directed toward the vehicle, at least one of the bushes interposed at the connection point between the H-shaped arm and the wheel support member is outward in the vehicle width direction. It is characterized in that it is composed of an anisotropic bush whose rigidity in the radial direction along the upward tilt direction is set to be low.

In the rear wheel suspension system according to claim 3 of the present invention, the lower region of the wheel support member and the vehicle body side member are
A toe control link connected by an A-shaped arm extending in the vehicle width direction, and the wheel support member and the vehicle body-side member extending in the vehicle width direction at a position behind the A-shaped arm in the vehicle front-rear direction. In the rear wheel suspension system connected by, the bush interposed at one of the two connection points connecting the A-shaped arm and the vehicle body side member in the vehicle front-rear direction is located outward in the vehicle width direction. Consists of an anisotropic bush with low rigidity set in the radial direction along the downward tilt direction, and the axis of the toe control link is
A straight line that is inclined outward in the vehicle width direction to the front side in the vehicle front-rear direction and that passes through the other connecting point of the two points connecting the A-arm and the vehicle body side member and the wheel side mounting point, and the toe control link The toe control link and the A-type arm are arranged so that a straight line passing through the axis line of (1) intersects with the vehicle width direction wheel side in plan view.

In the rear wheel suspension system according to a fourth aspect of the present invention, the lower region of the wheel support member and the vehicle body side member are
A toe control link connected by an A-shaped arm extending in the vehicle width direction, and the wheel support member and the vehicle body-side member extending in the vehicle width direction at a position behind the A-shaped arm in the vehicle front-rear direction. In the rear wheel suspension system connected by, the rubber bush interposed at one of the two connection points connecting the A-arm and the vehicle body side member in the vehicle front-rear direction is provided outward in the vehicle width direction. Consists of an anisotropic bush with a low rigidity in the radial direction along the upward tilt direction, and the axis line of the toe control link is directed outward in the vehicle width direction to the rear side in the vehicle front-rear direction. A straight line that passes through the other connecting point and the wheel side mounting point of the two points that connect the A-shaped arm and the vehicle body side member while inclining;
The toe control link and the A-shaped arm are arranged so that the straight line passing through the axis of the toe control link intersects with the vehicle body in the vehicle width direction in plan view.

According to any one of the inventions of the above respective constitutions, as described in claim 5, the anisotropic bush is provided with a currant in a bush main body which is an elastic body, so that It is preferable that the feature is realized by reducing the rigidity.

[0014]

When a braking force in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot / brake or the like, a moment in the windup direction is generated by the input. Due to this moment, a couple force that pushes down the front side in the front-rear direction of the vehicle body and pushes up the rear side in the front-rear direction of the vehicle body is input to the link connection portion of the wheel support member and the connection portion of the H-shaped arm on the vehicle body side.

In view of this, the operation of the invention described in claim 1 will be described. Here, in the following description of the operation, it is assumed that the outer cylinder side of the bush is fixed to the H-shaped arm and the inner cylinder side of the bush is connected to the vehicle body side member. The same applies to a configuration in which the outer cylinder side of the bush is fixed to the vehicle body side member and the inner cylinder side of the bush is fixed to the H-shaped arm.

First, considering the case where the anisotropic bush according to the present invention is adopted at the connecting point on the front side in the front-rear direction of the vehicle body, the wind-up moment pushes down the front side portion of the H-shaped arm in the front-rear direction of the vehicle body. The outer cylinder side fixed integrally with the H-shaped arm moves downward, and the inner cylinder side relatively moves upward. At this time, since the rigidity of the anisotropic bush is set low outward in the vehicle width direction and at the upper position, the inner cylinder side moves relatively upward while moving outward in the vehicle width direction.

However, since the inner cylinder side is attached to the vehicle body side member, the outer cylinder side, that is, the vehicle body side portion of the H-shaped arm on the front side in the vehicle front-rear direction moves inward in the vehicle width direction. This imparts a rotational displacement in the toe-in direction to the H-shaped arm. Due to the rotational displacement of the H-shaped arm in the toe-in direction, a toe change in the toe-in direction occurs in the wheel support member.

Here, in the construction in which the outer cylinder side of the bush is fixed to the vehicle body side member, when the front part of the H-shaped arm in the vehicle front-rear direction is pushed downward, it is fixed integrally with the H-shaped arm. Although the cylinder side moves downward, the inner cylinder moves downward while being moved inward in the vehicle width direction due to low rigidity inward and downward in the vehicle width direction, and the same action as described above occurs. .

Next, considering the case where the anisotropic bush of the present invention is adopted on the rear side in the vehicle front-rear direction, the wind-up moment pushes up the rear-side portion of the H-shaped arm in the vehicle front-rear direction. The outer cylinder side fixed integrally with the H-shaped arm moves upward, and the inner cylinder side relatively moves downward. At this time, since the anisotropic bush is set to have a low rigidity inward and downward in the vehicle width direction, the inner cylinder side relatively moves downward and moves inward in the vehicle width direction.

However, since the inner cylinder side is attached to the vehicle body side member, the outer cylinder side, that is, the vehicle body side portion of the H-shaped arm on the front side in the vehicle front-rear direction moves outward in the vehicle width direction. This imparts a rotational displacement in the toe-in direction to the H-shaped arm. Due to the rotational displacement of the H-shaped arm in the toe-in direction, a toe change in the toe-in direction occurs in the wheel support member.

Here, in the structure in which the outer cylinder side of the bush is fixed to the vehicle body side member, when the rear portion of the H-shaped arm in the vehicle front-rear direction is pushed upward, it is fixed integrally with the H-shaped arm. The inner cylinder moves upward, but because the rigidity of the outer position in the vehicle width direction and the upper position is low, the inner cylinder moves downward while moving outward in the vehicle width direction, and the same action as above occurs. To do.

Further, by setting the rigidity of a part of the bush to be low, the longitudinal rigidity of the entire bush is set to be low.
Next, the operation of the invention described in claim 2 will be described. Here, in the following description of the operation, it is assumed that the outer cylinder side of the bush is fixed to the H-shaped arm and the inner cylinder side of the bush is connected to the wheel support member. The same applies to a configuration in which the outer cylinder side of the bush is fixed to the wheel support member and the inner cylinder side of the bush is fixed to the H-shaped arm.

First, considering the case where the anisotropic bush of the present invention is used at the connecting point on the front side in the front-rear direction of the vehicle body, the wheel support member at the front portion of the H-shaped arm in the front-rear direction of the vehicle body moves downward due to the wind-up moment. Since it is pushed down, the outer cylinder side fixed integrally with the H-shaped arm moves upward, and the inner cylinder side relatively moves downward.

At this time, since the rigidity of the anisotropic bush is set to be low at the outer side and the lower side in the vehicle width direction, the inner cylinder side relatively moves downward and moves inward in the vehicle width direction. . Since the inner cylinder side is connected to the wheel support member, the front portion of the wheel support member in the front-rear direction of the vehicle body is displaced inward in the vehicle width direction, so that the wheel support member is rotationally displaced in the toe-in direction.

In the construction in which the outer cylinder side of the bush is fixed to the wheel support member, when the wheel support member side is pushed downward, the inner cylinder side fixed integrally with the H-shaped arm moves upward. However, because the rigidity of the outer and upper positions in the vehicle width direction is low, the inner cylinder moves upward while moving outward in the vehicle width direction, and the outer cylinder side relatively moves inward and downward in the vehicle width direction. By moving, an action similar to the above occurs.

By displacing the front side of the wheel support member in the front-rear direction of the vehicle body in this manner, the front portion of the H-shaped arm in the front-rear direction of the vehicle body is displaced inward in the vehicle width direction from the wheel support member. In addition to the input of the force toward the front side, the wind-up moment itself also inputs the force toward the front side of the H-shaped arm in the front-rear direction of the vehicle body, so that the front-side portion of the H-shaped arm in the front-rear direction of the vehicle body as a whole. Is loaded with a force directed inward and upward in the vehicle width direction. At this time, since the rigidity in the radial direction inward and upward in the vehicle width direction of the anisotropic bush used in the invention according to claim 2 is not set to be low, a predetermined windup rigidity at the time of braking is maintained. It can be secured.

Next, considering the case where the anisotropic bush of the present invention is adopted at the connection point on the rear side in the vehicle front-rear direction, the wheel support member on the rear side in the vehicle front-rear direction of the H-shaped arm due to the wind-up moment is as follows. Since it is pushed up, the outer cylinder side fixed integrally with the H-shaped arm moves downward, and the inner cylinder side relatively moves upward. At this time, since the rigidity of the anisotropic bush is set low outward in the vehicle width direction and at the upper position, the inner cylinder side moves relatively upward while moving outward in the vehicle width direction.

Since the inner cylinder side is connected to the wheel support member, the rear portion of the wheel support member in the front-rear direction of the vehicle body is displaced outward in the vehicle width direction, thereby imparting rotational displacement in the toe-in direction to the wheel support member. To be done. Here, in the configuration in which the outer cylinder side of the bush is fixed to the wheel support member, when the rear part of the H-shaped arm in the vehicle front-rear direction is pushed downward, the inner cylinder side integrally fixed to the H-shaped arm is Although it moves downward, the inner cylinder moves downward while moving inward in the vehicle width direction due to low rigidity inward and downward in the vehicle width direction.
The outer cylinder side relatively moves outward and upward in the vehicle width direction, and the same action as described above occurs.

As described above, the rear side of the wheel support member in the vehicle front-rear direction is displaced outward in the vehicle width direction, so that the wheel support member is located outside the vehicle width direction in the front portion of the H-shaped arm in the vehicle front-rear direction. In addition to the input of a force toward the rearward direction, a downward force is input to the rear portion of the H-shaped arm in the vehicle front-rear direction due to the wind-up moment itself. A force directed outward and downward in the vehicle width direction is applied to the portion. At this time, since the rigidity in the radial direction outward and upward in the vehicle width direction of the anisotropic bush used in the invention according to claim 2 is not set to be low, a predetermined wind-up rigidity during braking is obtained. It is possible to secure the same level of rigidity as conventional products.

Further, by setting the rigidity of a part of the bush to be low, the longitudinal rigidity of the entire bush is set to be low.
Next, the operation of the invention described in claim 3 will be described. When a braking force in the front-rear direction of the vehicle body is input to the ground contact surface of the wheel by a foot / brake or the like, a moment in the windup direction is generated by the input. Due to this moment, a couple force that pushes down the front side in the front-rear direction of the vehicle body and pushes up the rear side in the front-rear direction of the vehicle body is input to the A-shaped arm.

In the following description of the operation, it is assumed that the outer cylinder side of the bush is fixed to the A-shaped arm and the inner cylinder side of the bush is connected to the vehicle body side member. The same applies to a configuration in which the outer cylinder side of the bush is fixed to the vehicle body side member and the inner cylinder side of the bush is fixed to the A-shaped arm. First, considering the case where the anisotropic bush of the invention of the present application is adopted at the connecting point on the front side in the vehicle front-rear direction, the front portion in the vehicle front-rear direction of the A-shaped arm is pushed down by the wind-up moment, so that the H-shaped arm The outer cylinder side, which is integrally fixed with, moves downward, and the inner cylinder side relatively moves upward.

At this time, since the rigidity of the anisotropic bush is set lower inward and upward in the vehicle width direction, the inner cylinder side moves inward in the vehicle width direction while moving relatively upward. . However, since the inner cylinder side is attached to the vehicle body side member, the outer cylinder side, that is, the vehicle body side portion of the A-shaped arm on the front side in the vehicle front-rear direction moves outward in the vehicle width direction. This imparts rotational displacement in the toe-out direction to the A-shaped arm.

Here, when the outer cylinder side of the bush is fixed to the vehicle body side member, when the inner cylinder side, which is integrated with the H-shaped arm, moves downward, the bush moves outward and downward in the vehicle width direction. Since the rigidity is low, the inner cylinder side moves outward while moving downward, and the same action as described above occurs. Due to the rotational displacement of the A-shaped arm, the wheel-side connecting point of the A-shaped arm rotates rearward in the vehicle body front-rear direction around the vehicle body-side attachment point on the vehicle body front-rear direction rear side. By this rotation, the wheel-side connection point of the toe control link also rotates rearward in the vehicle front-rear direction about the vehicle-body-side connection point via the wheel support member.

At this time, the toe control link, the wheel support member, and the straight portion connecting the vehicle body side connection point and the wheel side connection point on the rear side in the vehicle body front-rear direction of the A-shaped arm constitute a trapezoidal link. In both of them, the toe control link is arranged such that the wheel-side connecting point is tilted to the front side in the vehicle front-rear direction in plan view, and the instantaneous rotation center of the wheel support member is located outward in the vehicle width direction. Due to the rotational displacement in the toe-out direction, the rotational displacement in the toe-in direction is imparted to the wheel support member.

Considering the case where the anisotropic bush of the present invention is adopted at the connecting point on the rear side in the vehicle front-rear direction, the rear portion of the A-shaped arm in the vehicle front-rear direction is pushed upward by the wind-up moment. Therefore, the outer cylinder side fixed integrally with the H-shaped arm moves upward, and the inner cylinder side relatively moves downward. At this time, since the anisotropic bush is set to have a low rigidity at the outer side in the vehicle width direction and at the lower position, the inner cylinder side relatively moves downward and moves outward in the vehicle width direction.

However, since the inner cylinder side is attached to the vehicle body side member, the outer cylinder side, that is, the vehicle body side portion of the A-shaped arm on the rear side in the vehicle front-rear direction moves inward in the vehicle width direction. This imparts a rotational displacement in the toe-in direction to the A-type arm. Here, when the outer cylinder side of the bush is fixed to the wheel support member, when the inner cylinder side integrated with the H-shaped arm moves upward, the rigidity inward and outward in the vehicle width direction is reduced. Since it is low, the inner cylinder side moves inward while moving inward in the vehicle width direction, and the same action as described above occurs.

By the rotational displacement of the A-shaped arm, the A
The wheel-side connecting point of the die arm rotates rearward in the vehicle front-rear direction about the vehicle-body-side attachment point on the vehicle body front-rear direction front side. By this rotation, the wheel-side connection point of the toe control link also rotates rearward in the vehicle front-rear direction about the vehicle-body-side connection point via the wheel support member. At this time, the toe control link, the wheel support member, and the straight portion connecting the vehicle body side connection point on the front side in the vehicle body front-rear direction front side and the wheel side connection point in the A-shaped arm together constitute a trapezoidal link. The link is arranged such that the wheel-side connecting point is tilted to the front side in the vehicle front-rear direction in a plan view, and the instantaneous rotation center of the wheel support member is located outward in the vehicle width direction. The rotational displacement imparts rotational displacement in the toe-in direction to the wheel support member.

Further, by setting the rigidity of a part of the bush to be low, the longitudinal rigidity of the entire bush is set to be low.
Next, the operation of the invention described in claim 4 will be described. When a braking force in the front-rear direction of the vehicle body is input to the ground contact surface of the wheel by a foot / brake or the like, a moment in the windup direction is generated by the input. Due to this moment, a couple force that pushes down the front side in the front-rear direction of the vehicle body and pushes up the rear side in the front-rear direction of the vehicle body is input to the A-shaped arm.

In the following description of the operation, it is assumed that the outer cylinder side of the bush is fixed to the A-shaped arm and the inner cylinder side of the bush is connected to the vehicle body side member. The same applies to a configuration in which the outer cylinder side of the bush is fixed to the vehicle body side member and the inner cylinder side of the bush is fixed to the A-shaped arm. First, considering the case where the anisotropic bush of the invention of the present application is adopted at the connecting point on the front side in the vehicle front-rear direction, the front portion in the vehicle front-rear direction of the A-shaped arm is pushed down by the wind-up moment, so that the H-shaped arm The outer cylinder side, which is integrally fixed with, moves downward, and the inner cylinder side relatively moves upward.

At this time, since the rigidity of the anisotropic bush is set low outward and upward in the vehicle width direction, the inner cylinder side moves relatively upward while moving outward in the vehicle width direction. . However, since the inner cylinder side is attached to the vehicle body side member, the outer cylinder side, that is, the vehicle body side portion of the A-shaped arm on the vehicle front-rear direction front side moves inward in the vehicle width direction. This imparts a rotational displacement in the toe-in direction to the A-type arm.

By the rotational displacement of the A-shaped arm, the A
The wheel-side connecting point of the die arm rotates forward around the vehicle body front-rear direction around the vehicle body-side attachment point on the vehicle body front-rear direction rear side. By this rotation, the wheel-side connecting point of the toe control link also rotates forward around the vehicle-body-side connecting point via the wheel support member. At this time, the toe control link, the wheel support member, and the straight portion connecting the vehicle body-side connecting point on the vehicle front-rear direction rear side of the A-shaped arm and the wheel-side connecting point together form a trapezoidal link. The control link is arranged such that the wheel-side connecting point is tilted rearward in the vehicle front-rear direction in plan view, and the instantaneous center of rotation of the wheel support member is located inward in the vehicle width direction. By the rotational displacement in the direction, the rotational displacement in the toe-in direction is applied to the wheel support member.

Next, considering the case where the anisotropic bush of the present invention is adopted at the connecting point on the rear side in the vehicle front-rear direction, the front portion in the vehicle front-rear direction of the A-shaped arm is pushed upward by the windup moment. The outer cylinder side fixed integrally with the H-shaped arm moves upward, and the inner cylinder side relatively moves downward. At this time, since the anisotropic bush is set to have low rigidity inward and downward in the vehicle width direction, the inner cylinder side moves inward in the vehicle width direction while moving relatively downward.

However, since the inner cylinder side is attached to the vehicle body side member, the outer cylinder side, that is, the vehicle body side portion on the rear side of the A-shaped arm in the vehicle front-rear direction moves outward in the vehicle width direction. This imparts rotational displacement in the toe-out direction to the A-shaped arm. By this rotational displacement of the A-shaped arm, the A
The wheel-side connecting point of the die arm rotates forward around the vehicle body front-rear direction around the vehicle body-side attachment point on the vehicle body front-rear direction rear side. By this rotation, the wheel-side connecting point of the toe control link also rotates forward around the vehicle-body-side connecting point via the wheel support member.

At this time, the toe control link, the wheel support member, and the straight portion connecting the vehicle body side connecting point and the wheel side connecting point on the front side in the vehicle body front-rear direction of the A-shaped arm together form a trapezoidal link. The toe control link is arranged such that the wheel-side connecting point is tilted rearward in the vehicle front-rear direction in plan view, and the instantaneous rotation center of the wheel support member is located inward in the vehicle width direction. Due to the rotational displacement in the toe-out direction, the rotational displacement in the toe-in direction is imparted to the wheel support member.

Further, by setting the rigidity of a part of the bush to be low, the longitudinal rigidity of the entire bush is set to be low.
The means for lowering the rigidity of each of the anisotropic bushes in the predetermined direction is realized by the configuration described in claim 5, for example. That is, the rigidity in the direction in which the curls are provided is set low.

[0046]

EXAMPLES Examples of the present invention will be described. First, the structure will be described. As shown in FIG. 1, a wheel (not shown) is rotatably supported by an axle 1 which is a wheel supporting member. An outer end portion of a lower arm 2 composed of an H-shaped arm is connected to a lower region of the axle 1.

The axle 1 and the lower arm 2 are connected to each other through two points arranged in the front-rear direction of the vehicle body, and bushes 3 are interposed at the respective connection points so that the bushes 3 can swing in a predetermined direction. There is. As shown in FIG. 2, each of the bushes 3 has an outer cylinder 3a and an inner cylinder 3b arranged in a nested manner with a predetermined space therebetween, and a rubber member is provided between the outer cylinder 3a and the inner cylinder 3b. And a bush main body 3c, which is interposed between the outer cylinder 3a side and the lower cylinder 2, and the inner cylinder 3b side is attached to the outer cylinder 3a. It is connected to the lower part of the axle 1 via a bolt.

The lower arm 2 extends inward in the vehicle width direction and is connected to a vehicle body side member such as a suspension member (not shown). The lower arm 2 and the vehicle body side member are connected to each other through two points aligned in the vehicle front-rear direction, and bushes 3 and 4 are provided at each of the connection points so that the lower arm 2 and the member can swing in a predetermined direction. ing.

In the bushes 3 and 4, the outer cylinders 3a and 4a and the inner cylinders 3b and 4b are arranged in a nested manner with a predetermined space therebetween, and the outer cylinders 3a and 4a and the inner cylinders 3b and 4b are respectively arranged.
Bush bodies 3c and 4c made of a rubber body are interposed between the outer cylinders 3a and 4a, and the outer cylinders 3a and 4a are integrally fixed to the lower arm 2 in a state in which the shaft is oriented in the vehicle front-rear direction. At the same time, the inner cylinders 3b and 4b are connected to a vehicle body side member (not shown) via mounting bolts.

Here, the pair of bushes 3 on the vehicle body side
Among the four, an anisotropic bush is adopted as the bush 4 on the front side in the front-rear direction of the vehicle body. This anisotropic bush 4 is
As shown in FIG. 2, curls 5 are formed on the inner cylinder 4b at positions outside and above the vehicle width direction and at positions inside and below the vehicle width direction of the bush body 4c. As a result, the anisotropic bushing 4 is set to have a low rigidity in the radial direction along the upward tilting direction outward in the vehicle width direction and a low rigidity in the front-rear direction of the vehicle body as a whole. Will be.

Reinforcing plates 6 are embedded at positions of the bush main body 4c outside and below the inner cylinder 4b in the vehicle width direction and above and below the inner cylinder 4b in the vehicle width direction. The required rigidity is secured. Further, the upper region of the axle 1 and the vehicle body side member are swingably connected to each other via an upper arm 7 which is an I arm and extends in the vehicle width direction.

The lower arm 2 and the upper arm 7 swing up and down around the swing shaft extending in the front-rear direction of the vehicle body so that the axle 1 and the wheels can bounce and rebound. In the rear wheel suspension system configured as described above, when a braking force directed rearward in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot brake or the like, a moment in the windup direction is generated by the input. Due to this moment, a couple force is input to the lower arm 2 to push down the front part in the front-rear direction of the vehicle body and push up the rear-side luck in the front-rear direction of the vehicle body.

At this time, paying attention to the bushes 3 and 4 on the front side in the vehicle front-rear direction of the lower arm 2, the front portion of the lower arm 2 in the vehicle front-rear direction is pushed downward by the wind-up moment, and is fixed integrally with the lower arm 2. The outer cylinders 3a, 4a side moving downwards, and the inner cylinders 3b, 4b side relatively moving upwards. At this time, since the anisotropic bush 4 interposed on the vehicle body side is set to have a low rigidity in the outer and upper positions in the vehicle width direction,
The inner cylinder 4b side relatively moves upward and moves outward in the vehicle width direction.

However, since the inner cylinder 4b side is attached to the vehicle body side member, the outer cylinder 4a side, that is, the vehicle body side portion of the lower arm 2 on the front side in the vehicle front-rear direction moves inward in the vehicle width direction. As a result, the lower arm 2 is provided with a rotational displacement in the toe-in direction. Due to the rotational displacement of the lower arm 2 in the toe-in direction, the axle 1 is pushed through the bush 3 on the front side in the vehicle front-rear direction and on the wheel side of the lower arm 2.
The front side of the vehicle body in the front-rear direction is displaced inward in the vehicle width direction, so that the axle 1 is rotationally displaced in the toe-in direction.

When the vehicle body side bush 4 (anisotropic bush) on the front side in the front-rear direction of the vehicle body bends, the wheel side bush 3 also bends, but the amount of deflection of the vehicle body side anisotropic bush 4 is greater. Since it is large, the front side in the vehicle front-rear direction of the axle 1 as a whole is displaced inward in the vehicle width direction. In this way, when the foot brake is applied by depressing the brake pedal, the toe change in the toe-in direction occurs in the axle 1 and further in the rear wheels, and the vehicle stability during braking is improved.

Considering a case where a rear-wheel passes over a protrusion on the road surface and a force in the longitudinal direction of the vehicle body is input to the wheel center when the vehicle is running, the wind-up moment input to the lower arm 2 is The opposite direction will be applied. That is, due to the action of front-rear force input to the wheel center, in the front portion of the lower arm 2 in the front-rear direction of the vehicle body, a force outward and upward in the vehicle width direction is input, but the anisotropic bush on the vehicle body side is input. In No. 4, by providing the curls 5, the rigidity of the entire bush is set to be low, and the bending direction is the direction of forming the currant 5. Therefore, the bush can be flexed more than before, and the longitudinal rigidity of the suspension is increased. Has been lower than before. That is,
This is advantageous in reducing harshness compared to the conventional one.

In the above embodiment, the anisotropic bush 4 is used.
The outer cylinder 4a side is fixed to the lower arm 2 and is connected to the inner cylinder 4b side vehicle body side member. However, the inner cylinder 4b side of the anisotropic bush 4 is connected to the lower arm 2 via a mounting bolt. Outer cylinder 4a
It may be configured to be fixed to the vehicle body side member. In this case, when focusing on the anisotropic bush 4, when the front side of the lower arm 2 in the vehicle front-rear direction is pushed down by the above-described braking, the inner cylinder 4b integrated with the lower arm 2 moves downward. However, since the rigidity of the lower side and the inner side in the vehicle width direction is low, the inner cylinder 4b moves inward in the vehicle width direction while moving downward, and exhibits the same action and effect as the above.

Next, the second embodiment will be described. First
The same members as those in the embodiment will be described with the same reference numerals.
The basic structure of the rear wheel suspension system of the second embodiment is the same as that of the first embodiment. However, only the configuration of the bush interposed at the vehicle body side attachment point of the lower arm 2 is different.

That is, of the pair of bushes interposed at the vehicle body side attachment point of the lower arm 2, the bush 3 on the front side in the vehicle front-rear direction is the bush 3 having the same rigidity as that of the conventional one. In addition, this is an example in which the anisotropic bush 4 described in the first embodiment is adopted for the bush on the rear side in the vehicle body front-rear direction. In the rear wheel suspension device configured as described above, when a braking force directed rearward in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot brake or the like,
A moment in the windup direction is generated by the input. Due to this moment, a couple force is input to the lower arm 2 to push down the front portion in the vehicle front-rear direction and push up the rear portion in the vehicle front-rear direction.

At this time, paying attention to the bush 3 on the rear side of the lower arm 2 in the vehicle front-rear direction, the rear portion of the lower arm 2 in the vehicle front-rear direction is pushed upward by the wind-up moment, and is fixed integrally with the lower arm 2. The outer cylinders 3a, 4a side moving upward moves relatively, and the inner cylinders 3b, 4b side relatively moves downward. At this time, since the anisotropic bush 4 on the vehicle body side is set to have low rigidity inward and downward in the vehicle width direction, the inner cylinder 4b is
The side moves inward in the vehicle width direction while moving relatively downward.

However, since the inner cylinder 4b side is attached to the vehicle body side member, the outer cylinder 4a side, that is, the vehicle body side portion of the lower arm 2 on the rear side in the vehicle front-rear direction moves outward in the vehicle width direction. As a result, the lower arm 2 is provided with a rotational displacement in the toe-in direction. Due to the rotational displacement of the lower arm 2 in the toe-in direction, the axle 1 passes through the bush 3 on the rear side of the vehicle body front-rear direction and the wheel side of the lower arm 2.
The rear side of the vehicle body in the front-rear direction is displaced outward in the vehicle width direction, so that the axle 1 is rotationally displaced in the toe-in direction.

When the bush 4 (anisotropic bush) on the vehicle body side on the rear side in the vehicle front-rear direction bends, the bush 3 on the wheel side also bends, but the amount of deflection of the anisotropic bush 4 on the vehicle body side Therefore, the rear side of the axle 1 in the vehicle front-rear direction is displaced outward in the vehicle width direction as a whole. In this way, when the foot brake is applied by stepping on the brake pedal, a toe change in the toe-in direction occurs on the axle 1 and further on the rear wheels, and the vehicle stability during braking is improved.

Considering a case where a force in the longitudinal direction of the vehicle body is input to the wheel center when the rear wheels pass over a protrusion on the road surface when the vehicle is running, the wind-up moment input to the lower arm 2 is The opposite direction will be applied. That is, due to the action of the longitudinal force input to the wheel center, a force inward and downward in the vehicle width direction is input to the rear portion of the lower arm 2 in the vehicle longitudinal direction. In the bush 4, by providing the curls 5, the rigidity of the entire bush 3 is set to be low, and the bending direction is the direction in which the curls 5 are formed. Therefore, the bush 3 can be flexed more than before, and the suspension 3 The front-rear rigidity is lower than before. That is, it is advantageous in reducing harshness as compared with the conventional case.

In the above embodiment, the anisotropic bush 4 is used.
The outer cylinder 4a side is fixed to the lower arm 2 and is connected to the inner cylinder 4b side vehicle body side member. However, the inner cylinder 4b side of the anisotropic bush 4 is connected to the lower arm 2 via a mounting bolt. Outer cylinder 4a
It may be configured to be fixed to the vehicle body side member. In this case, when focusing on the anisotropic bush 4, when the rear side of the lower arm 2 in the vehicle front-rear direction is pushed up by the above-described braking, the inner cylinder 4b integrated with the lower arm 2 moves upward. However, since the rigidity of the upper side and the outer side in the vehicle width direction is low, the inner cylinder 4b moves upward while moving upward, and exhibits the same action and effect as the above.

Further, in the first or second embodiment, an example in which the anisotropic bush having the above-described structure is adopted only on the front side or the rear side in the vehicle body front-rear direction of the bush on the vehicle body side will be described. However, the anisotropic bushes having the above configuration may be adopted for both the bushes on both sides in the front-rear direction of the vehicle body. In this case, due to the synergistic effect of both of the above actions and effects,
At the time of braking, the toe change in the toe-in direction can be further applied to the axle 1 and the wheels, and at the same time, it is further advantageous in reducing the harshness.

Next, the third embodiment will be described. The same members as those in the above embodiment are designated by the same reference numerals. The basic structure of the rear wheel suspension system of the third embodiment is the same as that of the first embodiment, except for the structure of the bush. That is, as shown in FIG. 3, the anisotropic bushes 8 are used for the bushes on the front side in the vehicle front-rear direction and on the wheel side, and the other bushes are isotropically configured to have the same rigidity as the conventional one. Bush 3 is used.

As shown in FIG. 3, the anisotropic bush 8 has the same basic construction as the conventional one, and has a bush body 8c made of a rubber body interposed between an inner cylinder 8b and an outer cylinder 8a. In the bush body 8c, the curls 9 are provided inward and upward in the vehicle width direction and outward and downward in the vehicle width direction with respect to the inner cylinder 8b. As a result, the anisotropic bushing 8 is set to have low rigidity in the radial direction along the inclination direction that is downward facing outward in the vehicle width direction.

Reinforcing plates 10 are embedded in the bush main body 8c at positions outside and above the inner cylinder 8b in the vehicle width direction and at positions inside and below the vehicle width direction, respectively. The rigidity is secured. In the rear wheel suspension system configured as described above, by the foot / brake,
When a braking force directed rearward in the vehicle front-rear direction is input to the contact surface of the wheel, the input causes a moment in the windup direction. This moment allows axle 1
On the other hand, a couple force that pushes down the front portion in the front-rear direction of the vehicle body and pushes up the rear portion in the front-rear direction of the vehicle body is input.

At this time, paying attention to the bushes 3 and 8 on the front side in the vehicle front-rear direction of the lower arm 2, the front portion of the lower arm 2 in the vehicle front-rear direction is relatively pushed upward by the wind-up moment, so that the lower arm 2 is integrated with the lower arm 2. The outer cylinders 3a and 8a side fixed to the upper cylinder move upward, and the inner cylinders 3b and 8b side move downward. At this time, since the anisotropic bush 8 on the vehicle body side is set to have a low rigidity inward and inward in the vehicle width direction, the inner cylinder 8 is
The b side moves inward in the vehicle width direction while moving relatively downward.

At this time, since the inner cylinder 8b side is attached to the axle 1, the front portion of the axle 1 in the vehicle front-rear direction moves inward in the vehicle width direction. As a result, a rotational displacement in the toe-in direction occurs in the axle 1. In addition,
When the wheel-side bush 8 (anisotropic bush) on the front side in the front-rear direction of the vehicle body bends, the vehicle-body side bush 3 also bends, but since the amount of deflection of the wheel-side anisotropic bushing 8 is larger, The front side in the vehicle front-rear direction of the axle 1 is displaced inward in the vehicle width direction.

As described above, when the foot brake is applied by stepping on the brake pedal, the toe change in the toe-in direction occurs in the axle 1 and further in the rear wheels, and the vehicle stability during braking is improved. Here, due to the wind-up moment, a relatively upward force is input to the front portion of the lower arm 2 in the front-rear direction of the vehicle body, and a force directed inward in the vehicle width direction is input due to a change in the toe-in of the axle 1. To be done. Therefore, as a whole, a force directed inward and upward in the vehicle width direction is input to the front portion of the lower arm 2 in the vehicle front-rear direction. At this time, in the anisotropic bushing 8 of the present embodiment, since the rigidity in the radial direction toward the inside in the vehicle width direction and upward is set to be high, the rigidity against the wind-up moment becomes high, and the unsprung mass during braking is increased. It is advantageous in preventing vibration and the like.

Considering a case where a force in the longitudinal direction of the vehicle body is input to the wheel center due to the rear wheels passing over a protrusion on the road surface when the vehicle is running, the wind-up moment input to the lower arm 2 is The opposite direction will be applied. That is, due to the action of front-rear force input to the wheel center, in the front portion of the lower arm 2 in the front-rear direction of the vehicle body, a force outward and downward in the vehicle width direction is input, but the anisotropic bush on the vehicle body side is input. In the case of No. 8, the rigidity of the bush 3 as a whole is set to be low by providing the curls 9, so that the bush 8 can be flexed more than before, and the longitudinal rigidity of the suspension is made lower than before. . That is, it is advantageous in reducing harshness as compared with the conventional case.

In the above embodiment, the anisotropic bush 8 is used.
The outer cylinder 8a side is fixed to the lower arm 2 and the inner cylinder 8b side is connected to the axle 1. However, the inner cylinder 8b side of the anisotropic bush 8 is connected to the lower arm 2 via a mounting bolt. And outer cylinder 8a
The side may be fixed to the axle 1. In this case, when paying attention to the anisotropic bush 8, when the front side of the lower arm 2 in the vehicle front-rear direction is pushed up by the above-described braking, the inner cylinder 8b integrated with the lower arm 2 moves upward. However, since the rigidity of the upper side and the outer side in the vehicle width direction is low, the inner cylinder 8b moves relatively upward and moves outward in the vehicle width direction. As a result, when viewed from the lower arm 2, the same action as above, such as the front side of the axle 1 in the vehicle front-rear direction being displaced inward in the vehicle width direction during braking,
Be effective.

Next, a fourth embodiment will be described. The same members as those in the above embodiment are designated by the same reference numerals.
The basic structure of the rear wheel suspension system of the fourth embodiment is the same as that of the third embodiment, except for the structure of the bush.
That is, an anisotropic bush is adopted as the bush 8 on the rear side of the vehicle body in the front-rear direction and on the wheel side, and the bush 3 having the same rigidity as that of the conventional one isotropically is adopted as the other bushes 3. ing.

The anisotropic bush 8 has the same structure as that of the anisotropic bush 8 described in the third embodiment (see FIG. 3), and is made of a rubber material between the inner cylinder 8b and the outer cylinder 8a. 8c is interposed, and the bush main body 8c
In the vehicle width direction inward and downward with respect to the inner cylinder 8b,
Also, a currant 9 is provided outside and above the vehicle width direction. As a result, the anisotropic bushing 8 is set to have low rigidity in the radial direction along the inclination direction that is directed outward in the vehicle width direction.

In the rear wheel suspension system configured as described above, when a braking force directed rearward in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot / brake or the like, a moment in the windup direction is generated by the input. To do. Due to this moment, a couple force that pushes the front side in the front-rear direction of the vehicle body downward and pushes up the rear side in the front-rear direction of the vehicle body is input to the axle 1.

At this time, paying attention to the bush 3 on the rear side of the lower arm 2 in the vehicle front-rear direction, the rear portion of the lower arm 2 in the vehicle front-rear direction is relatively pushed down by the wind-up moment, so that it is integrated with the lower arm 2. The outer cylinders 3a and 8a, which are fixed to, move downward, and the inner cylinders 3b and 8b side move to upper. At this time, since the anisotropic bush 8 on the vehicle body side is set to have a low rigidity at the outer side in the vehicle width direction and at the upper position, the inner cylinder 8b side moves relatively upward and outward in the vehicle width direction. Moving.

At this time, since the inner cylinder 8b side is attached to the axle 1, the rear portion of the axle 1 in the vehicle front-rear direction moves outward in the vehicle width direction. As a result, a rotational displacement in the toe-in direction occurs in the axle 1. In addition,
When the wheel-side bush 8 (anisotropic bush) on the rear side in the front-rear direction of the vehicle body bends, the vehicle-body side bush 3 also bends, but since the amount of deflection of the wheel-side anisotropic bush 8 is larger, As a result, the rear side of the axle 1 in the vehicle front-rear direction is displaced outward in the vehicle width direction.

In this way, when the foot brake is applied by stepping on the brake pedal, the toe change in the toe-in direction occurs in the axle 1 and further in the rear wheels, and the vehicle stability during braking is improved. Here, due to the wind-up moment, a downward force is input to a rear portion of the lower arm 2 in the vehicle front-rear direction, and a force outward toward the vehicle width direction is input due to a change in the toe-in of the axle 1. . Therefore, as a whole, a force directed outward and downward in the vehicle width direction is input to the front portion of the lower arm 2 in the vehicle front-rear direction. At this time, in the anisotropic bushing 8 of the present embodiment, the rigidity in the radial direction toward the outside in the vehicle width direction and upward is set to be high, so that the rigidity against the windup moment becomes high and the unsprung mass during braking is increased. It is advantageous in preventing vibration and the like.

Considering a case where a force in the vehicle front-rear direction is input to the wheel center when the rear wheels pass over a protrusion on the road surface when the vehicle is running, the wind-up moment input to the lower arm 2 is The opposite direction will be applied. That is, due to the action of the longitudinal force input to the wheel center, a force inward and upward in the vehicle width direction is input to the rear portion of the lower arm 2 in the vehicle longitudinal direction. In the bush 8, the rigidity of the entire bush is set to be low by providing the curls 9, so that the bush 8 can be flexed more than before, and the longitudinal rigidity of the suspension is made lower than before. . That is, compared to the conventional method, in reducing harshness,
Be advantageous.

In the above embodiment, the anisotropic bush 8 is used.
The outer cylinder 8a side is fixed to the lower arm 2 and the inner cylinder 8b side is connected to the axle 1. However, the inner cylinder 8b side of the anisotropic bush 8 is connected to the lower arm 2 via a mounting bolt. And outer cylinder 8a
It may be fixed to the side axle 1. In this case, when paying attention to the anisotropic bush 8, when the front side of the lower arm 2 in the vehicle front-rear direction is pushed down by the above-mentioned braking, the inner cylinder 8b integrated with the lower arm 2 moves downward. However, since the rigidity of the upper side and the inner side in the vehicle width direction is low, the inner cylinder 8b moves inward in the vehicle width direction while moving relatively downward. As a result, when viewed from the lower arm 2, the same action and effect as described above are exhibited, such that the rear side of the axle 1 in the vehicle front-rear direction is displaced outward in the vehicle width direction during braking.

In the third and fourth embodiments, the anisotropic bush 8 is provided only on one of the pair of bushes on the wheel side.
However, the pair of bushes on the wheel side may be the anisotropic bushes 8 described above.
Further, the anisotropic bushes 4 described in the first and second embodiments are adopted for the vehicle body side bushes as in the first and second embodiments, and all eight bushes are anisotropic. The bushes 4 and 8 may be used.

Next, the fifth embodiment will be described. First, the configuration will be described. As shown in FIG. 4, a wheel (not shown) is rotatably supported by an axle 20 which is a wheel supporting member. One end of a lower arm 21, which is an A-shaped arm, is vertically swingably connected to the lower region of the axle 20. The lower arm 21 extends inward in the vehicle width direction and is connected to a vehicle body-side member (not shown) via a pair of connecting points arranged in the vehicle front-rear direction.

Bushings 22 and 23 are interposed at the front and rear connecting points of the lower arm 21 and the vehicle body side member, respectively, so that they can be swung. The bushes 22,23
Each of which is composed of an inner cylinder 23b and an outer cylinder 23a, which are arranged in a nested manner at predetermined intervals, and a bush main body 23c made of a rubber body interposed between the two cylinders. The outer cylinder 23a side is a lower arm. 21 is integrally fixed to the inner cylinder 23b, and the inner cylinder 23b side is connected to the vehicle body side member via a mounting bolt.

Further, among the bushes 22 and 23, the bush 23 provided on the front side in the front-back direction of the vehicle body is
4 is an anisotropic bush 23. That is, as shown in FIG. 5, the curls 24 are provided inward and upward in the vehicle width direction and outward and downward in the vehicle width direction with respect to the inner cylinder 23b, respectively, so as to extend outward in the vehicle width direction. The radial rigidity along the downward tilt direction is set to be low.

Further, the upper region of the axle 20 and the vehicle body member are vertically swingably connected to each other via a camber control arm 25 which is an I arm. Further, the upper region of the axle 20 and the lower arm 21 are connected via a windup link 26. Also,
An arm extends rearward from the axle 20 in the front-rear direction of the vehicle body, and a toe control link 26 is connected to the tip of the arm so as to be vertically swingable. The toe control link 26 extends inward in the vehicle width direction, and its inner end portion is connected to a vehicle body side member via a bush 22 whose axis is vertically oriented.

This toe control link 26 is shown in FIG.
As shown in, the wheel side end is located on the vehicle width direction front side with respect to the vehicle body side end, so that the axis is inclined in the vehicle body front-rear direction. Further, a straight line L1 passing through the vehicle body side attachment point and the wheel side attachment point on the lower arm 21 in the vehicle longitudinal direction rear side.
And a straight line L2 along the axis of the toe control link 26
The lower arms 21 are arranged so that and intersect in the vehicle width direction outward in a plan view.

In the rear wheel suspension system configured as described above, when a braking force directed rearward in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot brake or the like, a moment in a windup direction is generated by the input. To do. Due to this moment, a couple force is input to the lower arm 21 by pushing down the front side in the vehicle front-rear direction and pushing up the rear side in the vehicle front-rear direction.

At this time, paying attention to the anisotropic bush 23 provided on the front side in the vehicle front-rear direction of the lower arm 21, the front portion of the lower arm 21 in the vehicle front-rear direction is pushed downward by the wind-up moment, so that the lower arm 21 is pushed down. Outer cylinder 2 fixed integrally with
The 3a side moves downward, and the inner cylinder 23b side relatively moves upward.

At this time, since the rigidity of the anisotropic bush 23 on the vehicle body side is set to be low inward and upward in the vehicle width direction, the inner cylinder 23b side moves relatively upward while moving in the vehicle width direction. Move inward. However, since the inner cylinder 23b side is attached to the vehicle body side member, the outer cylinder 23a side, that is, the vehicle body front portion in the vehicle front-rear direction front side of the lower arm 21 moves outward in the vehicle width direction. As a result, the lower arm 2
1 is given a rotational displacement in the toe-out direction.

Due to the rotational displacement in the toe-out direction generated in the lower arm 21, as shown in FIG. 7, the wheel side mounting point of the lower arm 21 is centered on the vehicle body side mounting point on the vehicle body front and rear direction rear side. The wheel 20 is pivotally displaced rearward, whereby the wheel-side attachment point of the toe control link 26 is also pivotally displaced through the axle 20 in the vehicle front-rear direction about the vehicle-body-side attachment point.

At this time, a trapezoidal link is formed by the vehicle body side member, the toe control link, the axle 20, and the straight portion connecting the vehicle body side connection point on the rear arm rear side of the lower arm 21 and the wheel side connection point. In addition, the toe control link has a wheel-side connecting point in plan view,
Since it is arranged to be inclined to the front side in the front-rear direction of the vehicle body, and the instantaneous center of rotation C1 of the axle 20 is located outward in the vehicle width direction, the rotational displacement of the lower arm 21 in the toe-out direction causes the axle 20 to rotate with respect to the axle 20. A rotational displacement in the toe-in direction is given.

In this way, when the foot brake is applied by stepping on the brake pedal, the toe change in the toe-in direction occurs in the axle 20 and further in the rear wheels, and the vehicle stability during braking is improved. Further, considering a case where a force in the vehicle front-rear direction is input to the wheel center when the rear wheels pass over a protrusion on the road surface when the vehicle is traveling, the lower arm 21
The windup moment input to is in the opposite direction.

That is, due to the action of the longitudinal force input to the wheel center, a force outward and upward in the vehicle width direction is input to the front portion of the lower arm 21 in the vehicle longitudinal direction. In the isotropic bush 23,
Since the rigidity of the bush 22 is set low by providing the curls 24, the bush 22 can be flexed more than before, and the longitudinal rigidity of the suspension is made lower than before. That is, compared to the conventional
It is advantageous in reducing harshness.

In the above embodiment, the anisotropic bush 2 is used.
Although the outer cylinder 23a side of 3 is fixed to the lower arm 21 and is connected to the inner cylinder 23b side vehicle body side member, the inner cylinder 23b side of the anisotropic bush 23 is attached to the lower arm 21 via a mounting bolt. It may be connected and fixed to the body member on the outer cylinder 23a side.

In this case, paying attention to the anisotropic bushing 23, when the front side of the lower arm 21 in the vehicle front-rear direction is pushed down by the braking as described above, the lower arm 2 is pushed down.
The inner cylinder 23b, which is integrated with 1, moves downward, but since the rigidity of the lower side and the outer side in the vehicle width direction is low, the inner cylinder 23b moves downward while moving outward in the vehicle width direction. , The same action and effect as above are exhibited.

Further, in the above embodiment, the wind up link 26 is connected to the upper region of the axle 20 and the lower arm 21.
The lower arm 21 and the toe control link 26, or the lower arm 21 and the camber control arm 25 may be connected to each other. Next, a sixth embodiment will be described. The same members as those in the fifth embodiment are designated by the same reference numerals.

The basic construction of the sixth embodiment is the same as that of the fifth embodiment, except for the construction of the bush connecting the lower arm 21 and the vehicle body side member. In other words, the bush 22 installed on the front side in the front-rear direction of the vehicle body employs the same isotropic bush 22 as the conventional one, and the bush installed on the rear side in the front-rear direction of the vehicle body has the above-mentioned fifth feature. An anisotropic bushing 23, which is similar to that described in the embodiment (see FIG. 5), is set to have low rigidity in the radial direction along the inclination direction that is downward outward in the vehicle width direction. It was done.

In the rear wheel suspension system configured as described above, when a braking force directed rearward in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot brake or the like, a moment in the windup direction is generated by the input. To do. Due to this moment, a couple force is input to the lower arm 21 by pushing down the front side in the vehicle front-rear direction and pushing up the rear side in the vehicle front-rear direction.

At this time, paying attention to the anisotropic bush 23 provided on the rear side of the lower arm 21 in the vehicle front-rear direction, the wind-up moment pushes the rear arm rear-side portion of the lower arm 21 upward. Outer cylinder 2 fixed integrally with the lower arm 21
The 3a side moves upward, and the inner cylinder 23b side relatively moves downward.

At this time, since the rigidity of the anisotropic bush 23 on the vehicle body side is set to be low outward and downward in the vehicle width direction, the inner cylinder 23b side moves relatively downward while moving in the vehicle width direction. Move out. However, since the inner cylinder 23b side is attached to the vehicle body side member, the outer cylinder 23a side, that is, the vehicle body side portion of the lower arm 21 on the vehicle front-rear direction front side moves inward in the vehicle width direction. As a result, the lower arm 2
1 is given a rotational displacement in the toe-out direction.

Due to the rotational displacement in the toe-out direction generated in the lower arm 21, as shown in FIG. 8, the wheel side mounting point of the lower arm 21 is rearward in the vehicle front-rear direction centering on the vehicle body side mounting point in the vehicle front-rear direction front side. The wheel-side attachment point of the toe control link 26 is also pivotally displaced in the vehicle body front-rear direction around the vehicle-body-side attachment point via the axle 20.

At this time, a trapezoidal link is formed by the vehicle body side member, the toe control link 26, the axle 20, and the straight portion connecting the vehicle body side connection point on the rear arm rear side of the lower arm 21 and the wheel side connection point. In addition, the toe control link 26 is arranged such that the wheel-side connecting point is tilted to the front side in the vehicle front-rear direction in plan view.
Since the instantaneous center of rotation of the axle 20 is located outward in the vehicle width direction, the rotational displacement of the lower arm 21 in the toe-out direction imparts rotational displacement in the toe-in direction to the axle 20.

In this way, when the foot brake is applied by stepping on the brake pedal, a toe change in the toe-in direction occurs in the axle 20 and further in the rear wheels, and the stability of the vehicle during braking is improved. Further, considering a case where a force in the vehicle front-rear direction is input to the wheel center when the rear wheels pass over a protrusion on the road surface when the vehicle is traveling, the lower arm 21
The windup moment input to is in the opposite direction.

That is, due to the action of the longitudinal force input to the wheel center, the force acting outward and upward in the vehicle width direction is input to the front portion of the lower arm 21 in the vehicle longitudinal direction, but the difference on the vehicle body side is input. In the isotropic bush 23,
Since the rigidity of the bush 22 is set low by providing the curls 24, the bush 22 can be flexed more than before, and the longitudinal rigidity of the suspension is made lower than before. That is, compared to the conventional
It is advantageous in reducing harshness.

In the above embodiment, the anisotropic bush 2 is used.
Although the outer cylinder 23a side of 3 is fixed to the lower arm 21 and the inner cylinder 23b side is connected to the vehicle body side member, the inner cylinder 23b of the anisotropic bush 23 is described.
The side may be connected to the lower arm 21 via a mounting bolt and fixed to the vehicle body side member on the outer cylinder 23a side.

In this case, paying attention to the anisotropic bush 23, when the front side of the lower arm 21 in the front-rear direction of the vehicle body is pushed up by the above braking, the lower arm 2
The inner cylinder 23b, which is integrated with 1, moves upward, but because of the low rigidity in the upper direction and the inner side in the vehicle width direction, the inner cylinder 23b moves upward while moving inward in the vehicle width direction. , The same action and effect as above are exhibited.

In the fifth and sixth embodiments, the anisotropic bush 23 is adopted only at one of the wheel-side mounting points of the lower arm 21. On the other hand, both the anisotropic bush 23
May be adopted. Next, a seventh embodiment will be described. The same members as those in the fifth embodiment are designated by the same reference numerals.

The basic construction of the seventh embodiment is similar to that of the fifth embodiment, and is arranged at the position where the lower arm 21 and the toe control link 26 are arranged and at the vehicle body-side connecting point of the lower arm 21 on the front side in the vehicle front-rear direction. The composition of the bush is different. That is, as shown in FIG. 9, the configuration of the bush interposed at the vehicle body side connecting point on the front side in the vehicle front-rear direction of the lower arm 21 is as shown in FIG. Since the curls 31 are formed at the inward and downward positions, respectively, the rigidity in the radial direction is set to be low along the inclination direction that is upward toward the vehicle width direction outward.

Further, in the toe control link 26, as shown in FIG. 10, the wheel side end portion is located rearward in the vehicle width direction with respect to the vehicle body side end portion, so that the axis is inclined in the vehicle body front-rear direction. There is. Further, the straight line passing through the vehicle body side attachment point and the wheel side attachment point on the rear side in the vehicle body front-rear direction of the lower arm 21 and the straight line along the axis of the toe control link 26 may intersect inward in the vehicle width direction in plan view. The lower arm 21 is disposed in the.

In the rear wheel suspension system configured as described above, when a braking force directed rearward in the vehicle front-rear direction is input to the ground contact surface of the wheel by a foot brake or the like, a moment in a windup direction is generated by the input. To do. Due to this moment, a couple force is input to the lower arm 21 by pushing down the front side in the vehicle front-rear direction and pushing up the rear side in the vehicle front-rear direction.

At this time, paying attention to the anisotropic bush 30 provided on the front side in the vehicle front-rear direction of the lower arm 21, the front portion of the lower arm 21 in the vehicle front-rear direction is pushed downward by the wind-up moment, so that the lower arm 21. Outer cylinder 3 fixed integrally with
The 0a side moves downward, and the inner cylinder 30b side relatively moves upward.

At this time, since the rigidity of the anisotropic bush 30 on the vehicle body side is set to be low at the outer side and the upper side in the vehicle width direction, the inner cylinder 30b side moves relatively upward while moving in the vehicle width direction. Move out. However, since the inner cylinder 30b side is attached to the vehicle body side member, the outer cylinder 30a side, that is, the vehicle body side portion of the lower arm 21 on the vehicle front-rear direction front side moves inward in the vehicle width direction. As a result, the lower arm 2
A rotational displacement in the toe-in direction is given to 1.

Due to the rotational displacement of the lower arm 21 in the toe-in direction, as shown in FIG. 11, the wheel side mounting point of the lower arm 21 is centered on the vehicle body side mounting point on the vehicle body front and rear direction rear side. The toe control link 26 is pivotally displaced forward, whereby the wheel side attachment point of the toe control link 26 is also pivotally displaced forward in the vehicle body front-rear direction around the vehicle body side attachment point via the axle 20.

At this time, a trapezoidal link is constituted by the vehicle body side member, the toe control link, the axle 20, and the straight portion connecting the vehicle body side connection point on the rear arm rear side of the lower arm 21 and the wheel side connection point. In addition, the toe control link has a wheel-side connecting point in plan view,
Since the axle 20 is tilted rearward in the vehicle front-rear direction, and the instantaneous rotation center of the axle 20 is located inward in the vehicle width direction, the displacement of the A-shaped arm in the toe-in direction causes the axle 20 to rotate relative to the axle 20. A rotational displacement in the toe-in direction is given.

As described above, when the foot brake is applied by stepping on the brake pedal, a toe change in the toe-in direction occurs in the axle 20 and further in the rear wheels, and the stability of the vehicle during braking is improved. Further, considering a case where a force in the vehicle front-rear direction is input to the wheel center when the rear wheels pass over a protrusion on the road surface when the vehicle is traveling, the lower arm 21
The windup moment input to is in the opposite direction.

That is, due to the action of the longitudinal force input to the wheel center, the force forward and outward in the vehicle width direction is input to the front portion of the lower arm 21 in the vehicle longitudinal direction. In the isotropic bush 30,
By providing the curls 31, since the rigidity of the entire bush 22 is set low and the bending direction is the direction of forming the curls 31, the bushing 22 can be flexed more than before and the longitudinal rigidity of the suspension can be improved. It is lower than before. That is, it is advantageous in reducing harshness as compared with the conventional case.

In the above embodiment, the anisotropic bush 3 is used.
The outer cylinder 30a side of No. 0 is described as being fixed to the lower arm 21 and connected to the inner cylinder 30b side vehicle body side member. However, the inner cylinder 30b side of the anisotropic bush 30 is attached to the lower arm 21 via a mounting bolt. It may be connected and fixed to the body member on the outer cylinder 30a side.

In this case, when paying attention to the anisotropic bush 30, when the front side of the lower arm 21 in the front-rear direction of the vehicle body is pushed down by the braking as described above, the lower arm 2 is pushed down.
Although the inner cylinder 30b that is integrated with 1 moves downward, the inner cylinder 30b moves inward in the vehicle width direction while moving downward because the rigidity of the lower inner side in the vehicle width direction is low. , The same action and effect as above are exhibited.

[0120]

As described above, in the rear wheel suspension system of the present invention, the toe-in change is generated in the rear wheel at the time of braking by the simple means of changing the structure of the bush so that the toe-in change occurs at the time of braking. There is an effect that the vehicle stability can be achieved. At the same time, by setting the rigidity of a part of the bush low, the longitudinal rigidity of the suspension is set low, and the harshness and the like can be reduced and the riding comfort of the vehicle can be improved.

As the means for setting the rigidity of the bush to be low, for example, the means described in claim 5 can be easily adopted.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a rear wheel suspension device according to a first embodiment of the present invention.

FIG. 2 is a side view showing an anisotropic bush according to a first embodiment of the present invention.

FIG. 3 is a side view showing an anisotropic bush according to a third embodiment of the present invention.

FIG. 4 is a schematic perspective view showing a rear wheel suspension device according to a fifth embodiment of the present invention.

FIG. 5 is a side view showing an anisotropic bush according to a fifth embodiment of the present invention.

FIG. 6 is a schematic plan view showing a positional relationship between a lower arm and a toe control link according to a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a behavior during braking of the fifth embodiment according to the present invention.

FIG. 8 is a diagram showing a behavior during braking of a sixth embodiment according to the present invention.

FIG. 9 is a side view showing an anisotropic bush according to a seventh embodiment of the present invention.

FIG. 10 is a schematic plan view showing a positional relationship between a lower arm and a toe control link according to a seventh embodiment of the present invention.

FIG. 11 is a diagram showing a behavior during braking of the seventh embodiment according to the present invention.

FIG. 12 is a perspective view showing a conventional rear wheel suspension device.

FIG. 13 is a diagram showing a behavior of the conventional rear wheel suspension system during braking.

[Explanation of symbols]

 1 Axle 2 Lower arm (H type arm) 3 Bushing 4 Anisotropic bushing 4a Outer cylinder 4b Inner cylinder 4c Bush body 5 Curling 8 Anisotropic bushing 9 Curling 26 Toe control link 23 Anisotropic bushing 24 Curling

Claims (5)

[Claims] 1. A lower region of a wheel support member and a vehicle body side member are connected by an H-shaped arm extending in a vehicle width direction,
The H-shaped arm and the wheel support member, and the H-shaped arm and the vehicle body-side member are swingably connected at two points arranged in the vehicle body front-rear direction via bushes whose swing axes are oriented in the vehicle body front-rear direction. In the rear wheel suspension device, at least one of the bushes interposed at the connection point between the H-shaped arm and the vehicle body-side member is radially rigid along the inclination direction that is directed upward in the vehicle width direction outward direction. A rear wheel suspension characterized in that it is made up of an anisotropic bush with a low height. 2. The lower region of the wheel support member and the vehicle body side member are connected by an H-shaped arm extending in the vehicle width direction,
The H-shaped arm and the wheel support member, and the H-shaped arm and the vehicle body-side member are swingably connected at two points arranged in the vehicle body front-rear direction via bushes whose swing axes are oriented in the vehicle body front-rear direction. In the rear wheel suspension device, at least one of the bushes interposed at the connection point between the H-shaped arm and the wheel support member has a radial rigidity along an inclination direction that is directed upward in the vehicle width direction outward direction. A rear wheel suspension characterized in that it is made up of an anisotropic bush with a low height. 3. The lower region of the wheel support member and the vehicle body side member are connected by an A-shaped arm extending in the vehicle width direction,
In the rear wheel suspension device, the wheel supporting member and the vehicle body side member are connected to each other by a toe control link extending in the vehicle width direction at a position rearward of the A-shaped arm in the vehicle front-rear direction. Of the two points that line up in the front-rear direction of the vehicle body connecting
It is composed of an anisotropic bush with a low rigidity in the radial direction along the inclination direction that is directed downward in the vehicle width direction, and the axis of the toe control link is directed outward in the vehicle width direction. A plane that is tilted forward in the front-rear direction and that passes through the other connecting point of the two points connecting the A-arm and the vehicle body-side member and the wheel-side mounting point and a straight line that passes through the axis of the toe control link are planes. A rear wheel suspension system characterized in that a toe control link and an A-shaped arm are arranged so as to intersect with each other in the vehicle width direction on the wheel side. 4. A lower region of the wheel support member and a vehicle body side member are connected by an A-shaped arm extending in the vehicle width direction,
In the rear wheel suspension device, the wheel supporting member and the vehicle body side member are connected to each other by a toe control link extending in the vehicle width direction at a position rearward of the A-shaped arm in the vehicle front-rear direction. The rubber bush interposed at one of the two connecting points of the vehicle body side member and the vehicle body side member in the front-rear direction is arranged in the radial direction along the inclination direction that is upward toward the vehicle width direction outward. It is composed of an anisotropic bush whose rigidity is set low, and the axis of the toe control link is inclined outward in the vehicle width direction to the rear side in the vehicle front-rear direction, and the A-shaped arm and the vehicle body side member are connected to each other. The toe control link and A are arranged so that a straight line passing through the other connecting point of the two points and the wheel chamfering attachment point and a straight line passing through the axis line of the toe control link intersect in the vehicle width direction on the vehicle body side in plan view. A rear wheel suspension device characterized in that a mold arm is arranged. 5. The anisotropic bush is realized by lowering the rigidity of the position where the curls are formed by providing the bush body which is an elastic body with the curls. The rear wheel suspension system described in any of 1.