JPS62289412A - Rear suspension for automobile - Google Patents

Abstract

PURPOSE:To improve both controllability and stability where a front and a rear link are adapted to secure a rear wheel to a car body side via elastic members in such a way as to be freely oscillated up and down by providing the elastic members while they are revolvingly displaced whereby changing a spring constant in the load input direction depending on deceleration. CONSTITUTION:Where a front and a rear link 2 and 3 extending in the car width direction are adapted to secure a rear wheel to a member 5 on a car body side via elastic members in such a way as to be freely oscillated up and down, the structure is constituted to be such that a spring constant in the load input direction from the links is changed by revolving the elastic members 7, which are provided respectively for the mounting sections of each link 2 and 3 to the member 5 on the car body side, around the oscillating center of the links. Displacement in rovolution of said elastic members 7 is effected through a link mechanism 11 with an electric motor 9 actuated. And the electric motor 9 is controlled by a controller 20 receiving the output from a deceleration sensor 19 in such a way that the spring constant of a front side elastic member 7 is made lower than that of a rear side elastic member 7 depending on deceleration at the time of deceleration.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a rear suspension for an automobile.

2. Description of the Related Art In a rear suspension of an automobile in which the rear wheel is supported by a vehicle body side member via a swinging member such as an arm or a link, a rubber bush or the like is interposed at the support point of the swinging member to the vehicle body side member. Setting the spring characteristics of the elastic member has a large effect on changes in the toe angle of the rear wheels caused by lateral forces when the vehicle turns.

Therefore, a hollow part is formed in the rubber bushing interposed at the support point of the swinging member to the vehicle body side member, and a structure is adopted in which hydraulic pressure can be introduced into the hollow part, and by controlling the hydraulic pressure, the hardness of the rubber bushing can be varied. A system has been developed that controls the toe angle change of the rear wheels in response to lateral force so that the toe-in tendency is strengthened at high speeds and the toe-in tendency is weakened at large steering turns. It is disclosed in the official gazette, Japanese Patent Application Laid-Open No. 60-146708, etc.

Problems that IJJ is trying to solve: However, with the method of introducing hydraulic pressure into the hollow part formed in the rubber bushing as described above, if high hydraulic pressure continues to be maintained in the hollow part of the rubber bushing, the durability of the rubber bushing decreases. Moreover, not only does this include the problem of oil resistance of the rubber bushing itself, but it also has the problem that it is fundamentally extremely difficult to realize a correspondence between hydraulic pressure and the spring characteristics of the rubber bushing.

Furthermore, there is a problem in that simply controlling the change in the toe angle of the rear wheels using the vehicle speed or steering angle cannot accurately respond to all driving modes of the vehicle.

The present invention aims to address the conventional problems as described above.

Means for Solving the Problems The present invention provides a parallel link type rear suspension in which a rear wheel is supported by two links on the front side and a rear side to a member on the vehicle body side so as to swing downward in an L direction. By rotating either or both of the front and rear elastic members interposed in the mounting portion of each rear link to the vehicle body side member, the link can be rotated around the swing center line of the link. The structure is configured such that the spring constant in the load input direction changes, and the elastic member is rotationally displaced relative to the link according to the deceleration of the vehicle, so that the spring constant of the backup elastic member is forward of the load input direction of the link during deceleration driving. This is characterized by the provision of an actuator that lowers the spring constant of the elastic member.

According to the function ■-, the amount of deflection of the elastic member due to the lateral force acting on the rear wheels during deceleration turning is larger on the Jij side elastic member than on the rear side elastic member, and the rear wheels are steered in the same direction as the front wheels. The toe angle changes in the direction of the toe angle, and the tendency of winding during deceleration turning, that is, the tendency of the turning radius to become smaller, is canceled out by the change in the toe angle, thereby obtaining steering characteristics in which the turning radius does not change.

Example Embodiments of the present invention will be explained below with reference to both figures.

1 to 4 show an embodiment of the present invention. In FIG. 1, 1 is a rear wheel, and the tips of the oil links 2 and 3 are pivoted to the rear wheel l. and link 2 after that
The proximal ends 21 and 31 of 3 are attached to a shaft 6 supported by a vehicle body side member 5 such as a cross member via an elastic member 7 as shown in FIG. 2 so as to be swingable in the L direction. ing. 4 is the rotation axis of the rear wheel 1.1.

Further, the tip of a radius rod 8 is attached to the rear wheel l, the base end 81 of which is attached to a vehicle body side member forward (or rearward) of the rear wheel via an elastic member so as to be able to swing by 1 ft. The radius rod 8 is configured to support the load acting in the longitudinal direction.

As shown in FIG. 2, the elastic member 7 includes an inner cylinder 71, an outer cylinder 72 concentric with the inner cylinder 71, and a rubber or the like interposed and fixed between the inner cylinder 71 and the outer cylinder 72. For example, as shown in FIG. 2(a), a gap 73a may be formed in a part of the elastic ring 73, or a second
By embedding an intermediate plate 73b such as a metal plate in a part of the elastic inner ring 73 as shown in FIG. is configured such that the spring constant changes depending on the angle, such as a high spring constant, and when the elastic member 7 is interposed between the shaft 6 and the link base end, By rotating the elastic member 7, it is possible to variably control the spring constant of the elastic member 7 relative to the main load on the rear wheel input via the link.

Although an electric motor or a hydraulic device may be used as the actuator for rotating the elastic member 7, the illustrated embodiment shows an example in which an electric motor 9 is used.

That is, the electric motor 9 is attached to the vehicle body side member 5, and rotationally displaces the elastic member 7 with respect to the link base end via the reduction gear lO, the link mechanism 11, etc.

FIG. 3 shows an example of a mounting portion of the elastic member 7.

That is, as shown in FIG. 3, the shaft 6 is fitted and supported via a bearing 13 in a cylindrical member 12 fixed to the vehicle body side member 5 by welding or the like so as to be able to rotate = T. Both end portions of the shaft 6 elastic member 7
The inner cylinder 71 of the link mechanism 11 is fitted to the inner cylinder 71 by means such as serration fitting, and the base end of the driven arm lie of the link mechanism 11 is fitted to the - end of the shaft 6 by means such as serration fitting. The nuts 14 are screwed onto the threaded portions at both ends of the shaft 6 and tightened to fix the elastic member 7, the driven arm llc, etc.

Of the elastic members 7 assembled and fixed to both ends of the shaft 6 as described above, a spherical collar 15 is press-fitted into the outer cylinder of the front elastic member 7a, and a retainer 16 is placed on the outer peripheral surface of the spherical collar 15. A spherical collar 15 is press-fitted into the outer cylinder of the rear elastic member 7b, and a retainer 16 is inserted into the outer peripheral surface of the spherical collar 15. The base end portion 31 of the backup link 3 is fitted and assembled so as to be rotatable.

In FIG. 3, reference numeral 17 indicates the driven arm llc of the link mechanism 11 and the connecting rod 1 (having a length adjustment mechanism).
The other end of the connecting rod llb is a joint that connects one end of the connecting rod llb to the tip of the driving arm lla fixed to the output shaft of the reducer IO, as shown in FIG. 1(a). are connected via. 18 is an oil seal.

The electric motor 9 has its rotation direction, rotation angle, etc. controlled by an output signal from a controller 20 based on a deceleration signal from an deceleration sensor 19 that detects the time rate of change in vehicle speed and emits a deceleration signal in accordance with the deceleration. It has become.

In the above, the left front and rear elastic members 7 are each 7a.
, 7b, and the front and rear elastic members on the right side are 7a'' and 7b, respectively.
b'', and the left and right elastic members 7b and 7b' on the rear side are fixed at p4 on the shaft 6 with a phase shift of 90'' from the left and right elastic members 7a and 7a' on the front side.

For example, during steady driving other than decelerating driving, as shown in Fig. 4 (
As shown in b), the left and right elastic members 7a, 7a' on the front side and the left and right elastic members 7b, 7b'' on the rear side are both intermediate springs in the front claw direction, that is, in the axial direction of the link. Set to maintain a constant state (a spring constant between a low spring constant and a high spring constant).

In this state, the elastic member 7a is affected by the cornering force as a lateral force acting on the rear wheel 1.1.

Even the deflection F□ of 7a', 7b, and 7b' is the same, and the toe angle of the rear wheels does not change when turning.

When the deceleration state is reached and the deceleration sensor 19 issues a deceleration signal, the controller 20 issues an output signal, and the motor 9 rotates at 1V, rotating the shaft 6 clockwise by 45''.

Then, the front and rear elastic members are rotated 45 inches clockwise relative to each link together with the shaft 6, as shown in Fig. 4 (b).
As shown in the figure, the elastic members 7a and 7a' on the front side in the main load input direction of each link have a low spring constant, and the elastic members 7b on the rear side,
7b' is in a state of high spring constant. In this state, the amount of deflection of the elastic members 7a, 7a" and 7b, 7b" (7) due to the cornering force as a lateral force acting on the rear wheel 1.1 is that the front elastic members 7a, 7a' are more deflected than the rear elastic member 7b. , 7b', the outer ring undergoes a toe-in change and the inner ring undergoes a toe-out change.

In general, in all types of automobiles, turning during deceleration is dangerous because it tends to curl, that is, the turning radius tends to gradually become smaller.

Therefore, as mentioned above, by rotating and displacing the elastic member 7 so that the front elastic member has a low spring constant and the rear elastic member has a high spring constant in response to lateral force in the deceleration state, the rear outer wheel is toe-in when decelerating and turning. , the inner wheel changes toe out, and the rear wheel l.

Since wheel 1.1 is slightly steered in the same direction as the front wheel, this change in the toe angle of rear wheel 1.1 acts to cancel the above-mentioned curling tendency, and the turning radius remains unchanged. It is possible to obtain the characteristics of
1- It is something that can be done.

In the case of the Mengi signal, a turning signal from a steering angle sensor, a lateral acceleration sensor, a yaw rate sensor, etc. is added to the deceleration signal from the deceleration sensor 19 as an information signal input to the controller 20, and the controller 20 detects the deceleration turning state. When this occurs, an output signal is issued to cause the elastic member 7 to
It is also possible to make the rotational displacement from the state shown in a) to the state shown in FIG. 4(o).

Additionally, in addition to the deceleration sensor 19, the vehicle speed is detected and a vehicle speed signal is manually sent to the controller 20 (a speed sensor is provided, and during steady driving other than deceleration, the springs of the front and rear elastic members 7 are activated according to the heavy speed). It is also possible to change the combination of constants.

An example thereof will be explained with reference to FIG.

That is, when traveling at low speed, as shown in FIG. 5(a), the front elastic member 7a,
7a' High spring constant, rear elastic members 7b, 7b
′ is a low spring constant, and the bending of the elastic member 7 due to the cornering force as a lateral force acting on the rear wheel 1.1 during turning is made more likely to be applied to the rear elastic members 7b, 7b′ than the front elastic members 7a, 7a′. so that it becomes large. Then, when turning, the toe angle changes so that the outer wheels are in the doorway and the inner wheels are in the toe-in state. This means that the rear wheels are steered in the opposite direction to the direction in which the front wheels are steered, resulting in good turning performance and the most favorable characteristics for low-speed steering, such as when parking the vehicle.

When running at medium speed, the elastic member 7 is rotated 45'' clockwise from the state shown in FIG.
The rear elastic member is set to have an intermediate spring constant in the left-right direction so that the amount of deflection due to cornering force is the same for both the front and rear elastic members. In this state, there is no toe angle change due to cornering force, and it is possible to measure the steering tendency during medium speed driving.

During high-speed driving, the elastic member 7 is further rotated 45'' clockwise from the state shown in FIG. 5(a), and the front elastic members 7a, 7a' are rotated against the left and right loads as shown in FIG. 5(c). is a low spring constant.

The rear elastic members 7b and 7b' have a high spring constant.

In this state, the deflection of the elastic member due to the cornering force is greater on the front side than on the rear side, and the toe angle changes such that the outer ring is toe-in and the inner ring is toe-out, as in the case of deceleration turning. This means that the rear wheels are steered in the same direction as the front wheels, so stability during high-speed running can be significantly improved.

can be controlled to the most preferable characteristics in each vehicle speed range as described below.

In the illustrated embodiment, both the front elastic member and the rear elastic member are rotated by the electric motor 9 to change the spring constants of all the elastic members. One of the elastic members, for example, the rear elastic member, is set to a high spring constant that does not change, and the other elastic member, for example, is configured so that only the front elastic member is rotated by the rotation of the electric motor 9. During deceleration, the Iiii side is set to a high spring constant. The elastic side elastic member may have a lower spring constant in the rightward direction, and the front elastic member may have a higher spring constant in the left-right direction during steady running other than during deceleration, or may have a lower spring constant during high-speed running.

Also, as an actuator for rotationally displacing an elastic member,
Not only an electric motor but also any hydraulic or vacuum actuator can be used.

Effects of the Invention According to the present invention configured as described above, in an automobile equipped with a parallel link type rear suspension, at least one of the elastic members interposed in each attachment support portion of the front and rear links to the vehicle body side member By rotating one elastic member around the hF swing center of the link, the spring constant in the direction of cocoon ball input from the link is changed, and the elastic member is rotated relative to the link during deceleration traveling. By displacing the rear wheels so that the toe angle of the rear wheels changes in the same direction as the front wheel steering direction during deceleration turning, the toe angle change of the rear wheels is reduced to reduce the tendency for the rear wheels to become entangled during deceleration turning, that is, the tendency for the turning radius to become smaller. Therefore, it is possible to obtain a steering characteristic in which the turning radius does not change, thereby improving maneuverability and improving safety.

In addition, in the unreleased IJJ, the elastic member has a directional spring constant, and the spring constant for the L outpost can be changed to α by simply rotating the elastic member, so the overall structure is extremely simple. In addition, it is possible to accurately perform variable control of the elastic constant, maintain the desired performance for a long period of time without reducing the service life of the elastic member, and make it possible to rotate and displace the elastic member. Since the front suspension does not directly act on the first stage, even if there is a failure in the actuator or the rotation transmission mechanism from the actuator to the elastic member, and the elastic member cannot be rotated, the movement will continue. There is almost no problem with the mechanical moat, which is extremely desirable from a safety standpoint, and can bring about great practical effects.

[Brief explanation of drawings]

FIGS. 1(A) and 1(O) are a plan view and a front view showing an embodiment of the present invention, and FIG. 2(A). (o) is a front view showing an example of the structure of the elastic member used in the present invention, and FIGS. 3(a) and 3(a) are specific structures of the attachment support part of the link to the vehicle body side member in FIG. 1. Cross-sectional top view and front view showing examples, Figures 4(a) and (o
) and Figure 5 (a). (a) and (c) are front views showing examples of rotation control modes of four elastic members on the front left and right and the rear left and right, which are interposed in the attachment support portion of the link to the vehicle body side member; Figure 4 (4)
, (a) is an example of eight modes of control according to deceleration, Fig. 5 (4)
, (α), and (c) respectively show examples of control modes depending on the vehicle speed. DESCRIPTION OF SYMBOLS 1... Rear wheel, 2, 3... Link, 5... Vehicle body side member, 6... Shaft, 7... Elastic member, 9... Electric motor, 19... Deceleration sensor , 20...controller. , 7+ffl +J 2 0 i3 Figure (i9

Claims (2)

[Claims] (1) In a parallel link type rear suspension for an automobile, in which the front and rear links supporting the rear wheels are respectively attached and supported via elastic members to the vehicle body side members so as to be able to swing up and down, each of the front and rear links is By rotating at least one of the front and rear elastic members respectively interposed in the attachment support portion to the vehicle body side member, the link is rotated about the swing center line of the link. The spring constant in the load input direction of the link is configured to change, and the elastic member is rotationally displaced relative to the link according to the deceleration during deceleration traveling, so that the spring constant of the rear elastic member is changed in the load input direction of the link. A rear suspension for an automobile, comprising an actuator that lowers the spring constant of a front elastic member. (2) In a parallel link type rear suspension for an automobile, in which the front link and the rear link supporting the rear wheels are respectively attached and supported via elastic members to the vehicle body side member so as to be able to swing up and down, the front link and the rear link supporting the rear wheels are rotatable to the vehicle body side member. To the shaft installed like this,
The spring constant in each direction is high and the spring constant in the direction perpendicular to the spring constant is low.The front and rear elastic members are fixed with a phase shift of 90 degrees from each other, and the outer periphery of the front and rear elastic members is The base ends of the front and rear links are fitted so as to be relatively rotatable, and an actuator is provided to rotate the shaft in accordance with the deceleration of the automobile, and the actuator is fixed to the shaft and the shaft. The front and rear elastic members rotate and the spring constant of the elastic members in the direction of load input from the front and rear links is low for the front elastic member and high for the rear elastic member during deceleration running. Rear suspension for automobiles.