JPS62289409A - Rear suspension for automobile - Google Patents

Abstract

PURPOSE:To attempt improvement of running stability particularily at high speed where a front link is 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 car speed. CONSTITUTION:In a parallel link type rear suspension, the links 2 and 3 of a front wheel extending in the car width direction are adapted to secure a rear wheel 1 to the 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. And displacement in revolution 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 car speed sensor 19 in such a way that the spring constant of a rear side elastic member 7 is made lower than that of a front side elastic member 7 in case of running at high speed.

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 automatic lj.

Conventional technology For example, in an automatic type using a parallel link rear suspension in which the rear wheels are supported vertically and swingably by front and rear links, when a lateral force is applied to the rear wheels such as when turning, the amount of lateral displacement due to the lateral force is calculated. It has been generally known that stability at high speeds can be improved by making the front link larger than the rear link so that the toe angle of the outer rear wheel (hereinafter referred to as the outer wheel) tends to be toe-in with respect to the turning center. well known.

However, this approach has the disadvantage that while stability in high-speed driving ranges is improved, turning performance in low-speed driving ranges is deteriorated.

Therefore, a hollow part is formed in the rubber bushing inserted at the axle attachment point of the front and rear links to the vehicle body side member, and the hydraulic pressure is introduced into the hollow part, and the hydraulic pressure introduced into the hollow part is controlled depending on the vehicle speed. By changing the hardness of the rubber bushings, the hardness of the rubber bushings can be changed in accordance with the vehicle speed, and a system has been developed in which the rear wheels tend to toe-in against lateral forces only when driving at high speeds. -146
It is published in Publication No. 707.

Problems to be Solved by the Invention However, in the method of introducing hydraulic pressure into the hollow part formed in the rubber bushing as described above, if a high hydraulic pressure is maintained in the hollow part (except when driving at high speed, the hydraulic pressure in the hollow part will be low). (maintained in a high state), the durability of the rubber bushing is reduced, and not only does it include problems with the oil resistance of the rubber body, but also basically it is difficult to realize the correspondence between hydraulic pressure and the spring characteristics of the rubber bushing. The problem is that it is extremely difficult.

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 vehicle body side member so as to be able to swing up and down. By rotating either or both of the elastic members before and after the elastic member installed in the axle stone part of each link on the vehicle body side member around the swing center line of the link, the load can be input from the link. The front elastic member is configured to have a structure in which the spring constant in the direction changes, and is provided with an actuator that rotationally displaces the elastic member relative to the link depending on the vehicle speed. It is characterized by being configured to be low, and the rear elastic member to be high.

According to the function and description, when running at medium or low speeds, the front and rear elastic members have the same spring constant, or the spring constant of the rear elastic member is lower than that of the front side, to ensure accurate turning performance, and when running at high speeds. At this time, the spring constant of the front elastic member is lower than that of the rear side, and the outer wheels of the rear wheels tend to toe-in and the inner wheels tend to toe-out due to lateral force during turning, which can significantly improve high-speed stability.

Example Examples of the present invention will be described below with reference to both cases.

1 to 4 show an embodiment of the present invention. In FIG. 1, l is a rear wheel, and the front and rear links 2 and 3 have front and rear links 2 and 3 pivotally attached to the rear wheel 1. , the previous and next links 2
The proximal ends 21 and 31 of 3 are attached to a shaft 6 supported by the vehicle body side member 5 of the cross member shade via an elastic member 7 as shown in FIG. 2 so as to be swingable in the L direction. There is. 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 1, and its base end 81 is attached to a member on the vehicle body side forward (or rearward) of the rear wheel so as to be swingable via an elastic member. The radius rod 8 is configured to support the load 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
As shown in Figure (1), by embedding an intermediate plate 73b such as a metal plate in a part of the elastic inner ring 73, for example, the spring constant is set to be low in the x-X direction, and the Y-Y line perpendicular thereto is The spring constant is configured to change depending on the angle, such as a high spring constant in the direction, 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 the electric motor 9 is
The elastic member 7 is rotationally displaced with respect to the link base end via the lO, the link mechanism 11, and the like.

FIG. 3 shows a specific example of the attachment portion of the elastic member 7. As shown in FIG.

That is, as shown in FIG. 3, the shaft 6 rotates n1 via a bearing 13 on a cylindrical member 12 fixed to the vehicle body side member 5 by welding or the like.
The inner cylinder 71 of the elastic member 7 is fitted to both end portions of the shaft 6 in an R stage such as by serration fitting,
In addition, the base end of the driven arm llc of the link mechanism 11 is fitted to one end of the shaft 6 by means of a serration fitting, and the cheat 2 14 is screwed into the threaded portions at both ends of the shaft 6. The elastic member 7, the driven arm llc, etc. are fixed by tightening together.

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. The base end 21 of the front link 2 is fitted and assembled so as to be rotatable, and the spherical collar 15 is press-fitted into the outer cylinder of the rear elastic member 7b. The base end portion 31 of the rear link 3 is fitted and assembled so as to be rotatable.

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

The direction and angle of rotation of the electric motor 9 are controlled by output signals from a controller 20 based on a vehicle speed signal from a sensor that detects a running state, such as a vehicle speed sensor 19 that detects vehicle speed.

In the above, the left front and rear elastic members 7 are each 7a
, 7b, and the front and rear elastic members 7 on the right side are respectively 7a',
7b'', and assemble the left and right elastic members 7b and 7b' on the rear side with an angular displacement of 90@ with respect to the left and right elastic members 7a and 7a' on the front side, for example, as shown in Fig. 4 (A). The left and right elastic members 7a and 7a' on the front side have a high spring constant in the left and right direction (the axial direction of the link 2) and have a low spring constant in the L5 direction, and the left and right elastic members 7b and 7b'' on the rear side The spring constant is low in the direction (axial direction of the link 3) and high in the downward direction. In this state, the elastic members 7a, 7a'' and 7b,
The deflection of 7b' is larger in the rear elastic members 7b, 7b' than in the front elastic members 7a, 7a'', so the 1 (ring (hereinafter referred to as the outer ring) on the side far from the center of rotation is toe-out and the center of rotation is The rear wheel (hereinafter referred to as the F inner wheel) on the side closer to the front wheel is in a toe-in state.When turning, the outer wheel changes toe-out and the inner wheel changes toe-in. Since wheel 1.1 has been steered in the opposite direction, the turning performance is good, and this is the most desirable characteristic when steering at low speeds, such as when driving at a low speed, for example, when driving in a low vehicle speed range. When the controller 20 maintains the state shown in FIG. 4(a) in response to a signal from the vehicle speed sensor 19, suspension characteristics focusing on turning performance can be obtained as described above.

When the vehicle is traveling in a medium speed range, the controller 20 issues an output signal in response to a signal from the vehicle speed sensor 19, and the electric motor 9 rotates to rotate the driving arm lla clockwise in FIG. 1 (0). , the left and right shafts 6, 6 clockwise through the connecting rod llb and the driven arm 11c.
5" rotation. Then, together with the shaft 6.6, all the elastic members 7 on the front and rear sides are rotated 45" clockwise with respect to the base ends 21, 31 of each link 2, 3. As shown in FIG. 4(a), all the elastic members 7a, 7a''
, 7b.

7b' is in a state of an intermediate spring constant (a spring constant between a low spring constant and a high spring constant) in the main load direction input from each link, that is, in the left-right direction, and the front elastic member 7a is affected by the cornering force when turning. 7a'' and the rear elastic member 7b.

7b'' is the same, and the toe angles of both the outer and inner wheels do not change, making it possible to measure the direction of maneuverability during medium-speed running.

In the high vehicle speed range, the controller 20 issues an output signal in response to the signal from the vehicle speed sensor 19, causing the electric motor 9 to rotate and rotate the shaft 6 further 45 inches clockwise than in the middle vehicle speed range.

Then, as shown in FIG. 4(C), the front elastic member 7a,
7a'' has a low spring constant on the left and right, and the rear elastic member 7b
, 7b' are in a state where the spring constant is high on the left and right sides, and the outer ring changes toe-in and the inner ring changes toe-out due to cornering force during turning. This means that the rear wheels 1. Since this means that the vehicle has been steered, the stability during high-speed running can be significantly improved.

The above embodiment shows an example in which 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 so that the manner in which the toy changes due to cornering force can be controlled. However, one of the front elastic member and the rear elastic member, for example, the rear elastic member is set to an intermediate spring constant where the spring constant does not change, and the other side, for example, only the front elastic member is rotated by the rotation of the electric motor 9, and at low speeds. has a high spring constant in the left-right direction to tend to toe-out of the outer wheels; when driving at medium speeds, it has an intermediate spring constant in the left-right direction to suppress changes in the toe angle of the rear wheels when turning, and when driving at high speeds, it has a low spring constant in the left-right direction when turning. The outer ring may also have a tendency to toe-in.

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.

Advantages of the Invention According to the present invention configured as described above, in an automobile equipped with a parallel link suspension suspension system, elastic members interposed in respective mounting support portions of front and rear links to vehicle body members are provided. At least one elastic member is connected to the L of the link.
The structure is structured such that the spring constant in the front pawl input direction from the link changes by rotating around the center of downward swing, and the elastic member is rotationally displaced relative to the link according to the vehicle speed to achieve high-speed running steering. By changing the toe angle of the rear wheels in the same direction as the front wheel steering direction, it is possible to achieve remarkable high-speed running stability without deteriorating turning performance during medium or low-speed running.

Further, in the present invention, the elastic member has a directionality of a spring constant,
Since the spring constant for the main load can be arbitrarily changed and set by simply rotating the elastic member, the overall structure is extremely simple and the spring constant can be accurately controlled. It is possible to maintain the desired function for a long period of time without reducing the service life of the elastic member, and since the suspension load does not directly act on the means for rotationally displacing the elastic member, in the unlikely event that the actuator or actuator Even if there is a failure in the rotation transmission mechanism leading to the elastic member and the elastic member cannot be rotated, there is almost no problem with the running function, and it is extremely desirable from a safety standpoint, and it has a great practical effect. It's something you get.

[Brief explanation of the drawing]

FIGS. 1(A) and 1(0) are a side explanatory view and a front only explanatory view showing an embodiment of the present invention, and FIG. 2(A). (α) is a front view showing an example of the structure of the elastic member used in the present invention, and FIG. (0) is a cross-sectional plan view and a front view showing a specific structural example of the attachment support part of the link to the vehicle body side member in FIG. 1, and FIGS. 4 (a), (o), and (c) are the vehicle body of the link. It is a front view which shows the example of the rotation control aspect of the four elastic members of front left and right and rear side left and right which are interposed in the attachment support part to a side member, respectively. l... Rear wheel, 2.3... Link, 5... Vehicle body side member, 6... Axis, 7... Elastic member, 9... Electric motor, 19... Vehicle speed sensor, 20...controller. More than 1 Figure/lz Lola← 3 Figure <A) 1:! 7'4 ko

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 structure has a structure in which the spring constant in the direction of load input changes, and an actuator is provided to rotationally displace the elastic member relative to the link depending on the vehicle speed. An automobile rear suspension characterized by a low spring constant. (2) In a parallel link type rear suspension for an automobile, in which the front and rear links that support the rear wheels are respectively attached and supported to the vehicle body side member via elastic members so as to be able to swing up and down, On the attached shaft,
The front and rear elastic members, each having a high spring constant in one direction and a low spring constant in the orthogonal direction, are fixed with a phase shift of 90° 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 that they can rotate relative to each other, and an actuator is provided to rotate the shaft in accordance with the vehicle speed. The rear suspension for an automobile is characterized in that the elastic member rotates so that the spring constant in the direction of load input from the front and rear links during high-speed running is made low for the front elastic member and high for the rear elastic member. .