JPS62289410A - Rear suspension for automobile - Google Patents

Abstract

PURPOSE:To attempt improvement of running stability particularily at high speed by providing a shaft which is rotated depending on car speed, on a car body side whereby adapting elastic members to secure rotatably a front and a rear link which support a rear wheel in such a way as to be freely oscillated up and down, onto said shaft while their spring constants are made different. CONSTITUTION:Where a front and a rear link 2 and 3 extending in the car width direction are adapted to secure a rear wheel 1 to a member 5 on a car body side via elastic members in such a way as to be freely oscillated up and down, a front and a rear elastic member 7a and 7b where a spring constant in one direction is made high, and a spring constant in the direction normally intersecting the aforesaid direction is made low, are fixed on a shaft 6 secured rotatably on the member 5 on the car body side in such a way as to be shifted each other by 90 deg. in phase. And the shaft 6 is rotated by an electric motor 9 through a link mechanism 11. 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 front side elastic member 7 is lower than that of a rear 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 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. The spring characteristics of the elastic member are as follows:
Ride comfort.

and have a major impact on steering stability, etc.! However, in general, the spring characteristics of the E valve regulating member are determined as a compromise between various requirements such as vibration and noise reduction of heavy bodies, four corridors for ride comfort, and direction of steering stability. This is Tingdong.

In contrast, a rubber bushing has been developed in which a hollow part is formed in the rubber bushing, and by introducing hydraulic pressure into the hollow part, the hardness of the rubber bushing can be controlled to varying degrees. , Japanese Patent Publication No. 60-14670
It will be published in Gazette No. 8 Kasa.

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 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 the rubber bushing itself have a problem with its oil resistance, but it also has the problem that it is basically extremely difficult to realize a corresponding relationship between the hydraulic pressure and the spring characteristics of the rubber bushing.

Means for Solving the Problems The present invention provides a parallel link type rear suspension for an automobile in which a front link and a rear link supporting a rear wheel are respectively attached and supported to a vehicle body side member via an elastic member so as to be movable under E. In this case, the front and rear elastic members, each having a high spring constant in one direction and a low spring constant in the perpendicular direction, are attached to a shaft rotatably attached to a member on the side of the vehicle body, and the front and rear elastic members are attached to each other by 90".
The base ends of the front and rear links are fitted to the outer peripheries of the front and rear elastic members so that they can rotate relative to each other, and the shafts are fixed to each other in a phase-shifted state. The invention is characterized in that it is provided with an actuator that rotates in accordance with the movement.

According to the operation description, before the actuator is fixed to the shaft with a phase of 90'' to W by rotating the shaft,
The rear elastic members rotate together as an axis, changing the spring constant of each of the front and rear elastic members in response to the lateral force acting on the rear wheel, and changing the toe angle of the rear wheel. For example, at low speeds, the toe angle is in the opposite direction to the turning direction, at medium speeds, there is no change in toe angle, and at high speeds, the toe angle is in the same direction as the turning direction, so that it can be controlled as appropriate to suit the driving conditions. .

Example Embodiments of the present invention will be described 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 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 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 movable in the L''FF direction. .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 so that the base end 81 is swingably attached to a vehicle body member forward (or rearward) of the rear wheel via an elastic member, and acts on the rear wheel l. 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 an inner cylinder 71 and an outer cylinder
2, and an elastic ring 73 made of an elastic member such as rubber interposed and fixed between the elastic ring 73 and a gap 73a formed in a part of the elastic ring 73, for example, as shown in FIG. 2(A). For example, by embedding an intermediate plate 73b such as a metal plate in a part of the elastic inner ring 73 as shown in FIG.
The spring constant is configured to change depending on the angle, such as a low spring constant in the linear direction and a high spring constant in the Y-Y line direction perpendicular to the linear direction, and the elastic member 7 is connected between the shaft 6 and the link base end. By rotating the elastic member 7 with respect to the base end of the link, the spring constant of the elastic member 7 relative to the load applied to the rear wheel manually applied via the link can be variably controlled. It has become.

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 ilO, the link mechanism 11, and the like.

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 rotatably fitted and supported via a bearing 13 into 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 by means such as serration fitting, and the base end of the driven arm llc of the link mechanism 11 is fitted to one 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. 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 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 10, 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 vehicle speed signal from a sensor that detects the running state, such as a vehicle speed sensor 19 that detects heavy speed.

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 7, respectively.
b', and the rear left and right elastic members 7b and 7b' are assembled with an angular displacement of 90° relative to the front left and right elastic members 7a and 7a'', 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-right direction (the axial direction of the link 2) and have a low spring constant in the vertical direction, and the left and right elastic members 7b and 7b' on the rear side have a spring constant in the left-right direction. The spring constant is low in the axial direction of the link 3 and high in the vertical direction. In this state, the amount of deflection of the elastic members 7a, 7a'' and 7b, 7b'' due to the cornering force as a lateral force acting on the rear wheel 1.1 during turning is smaller than that of the front elastic members 7a, 7a'' than the rear elastic member 7b, 7b'' is larger, so the rear wheel on the side farther from the turning center (hereinafter referred to as the outer wheel) is toe-out, and the rear wheel on the side closer to the turning center (hereinafter referred to as the inner wheel) is in the toe-in condition. In this way, when the outer wheel changes toe-out and the inner wheel changes toe-in when turning, it means that the rear wheels 1.1 are steered in the opposite direction □ with respect to the steering direction of the steered wheels, so turning performance is good. For example, this is the most preferable characteristic when steering at a low speed such as when parking in a garage, and when the vehicle is running in a low speed range, the controller 20 is set to the state shown in FIG. 4(A) by the signal from the vehicle speed sensor 19. By maintaining the suspension characteristics as described in item 1, it is possible to obtain suspension characteristics with a focus on turning performance.

When the vehicle is running in a medium speed range, the controller 20 issues an output signal t) in response to a signal from the vehicle speed sensor 19, and the electric motor 9 rotates to move the drive side arm lla as shown in FIG. 1(a).
is rotated clockwise, and the left and right shafts 6, 6 are rotated 45° clockwise via the connecting row, door llb, and driven side arm lie. Then, all the elastic members 7 on the front and rear sides are integrated with the shafts 6, 6, and each link 2, 3
45'' clockwise relative to the base end portions 21, 31 of 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 t 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.

Since the amount of deflection of 7b' is the same, the toe angle of both the outer and inner wheels does not change, and the steering tendency at medium speed can be measured.

In the high vehicle speed range, the controller 20 issues an output signal in response to the signal from the heavy speed sensor 19, causing the electric motor 9 to rotate and rotate the shaft 6 further 45° 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'' has a high spring constant on the left and right sides, and the outer wheel changes toe-in and the inner wheel changes toe-out due to the cornering force when turning. This means that the rear wheels 1.1 turn in the same direction as the steered wheel. Since the vehicle is steered, stability during high-speed driving can be significantly improved.

Additionally, when turning during acceleration, a front-engine, front-drive vehicle (hereinafter referred to as a FF vehicle) tends to have a larger turning radius, that is, it tends to understeer. In the case of a vehicle (hereinafter referred to as an FR vehicle or RR vehicle), on the contrary, the turning radius tends to become smaller, that is, there is a tendency to oversteer. Therefore, the controller 20 calculates the rate of change over time, that is, acceleration/deceleration, from the vehicle speed signal from the vehicle speed sensor 19, and adds a steering sensor, lateral acceleration sensor, or yaw rate sensor, etc. to detect the turning state, and When turning under acceleration, for example, in a FF vehicle, the electric motor 9 is operated to rotate the shaft 6 and the elastic member 7 so that the outer ring is toe-out and the inner ring is toe-in, as shown in Figure 4 (a). In addition, in the case of an FR or FF vehicle, the electric motor 9 is operated to rotationally displace the shaft 6 and the elastic member 7 so that the outer ring is toe-in and the inner ring is toe-out as shown in Fig. 4 (c). By doing so, the steering characteristic during accelerated turning can be corrected to a neutral characteristic, that is, a characteristic in which the turning radius hardly changes during accelerated turning.

Furthermore, when turning while decelerating, the turning radius tends to become smaller for both FF, FR, and RR cars, so when turning while decelerating from a fixed position, the outer wheel The electric motor 9 is set so that the inner ring is toe-in and the inner ring is toe-out.
By operating the shaft 6 and the elastic member 7 to rotationally displace it, the turning radius can be corrected to a characteristic that hardly changes.

As shown in E, the spring constant of the elastic member can be changed and controlled to suit the current running conditions by an extremely simple operation of simply rotating the shaft 6 according to various running conditions.

Although the above embodiment shows an example in which the shaft 6 is rotationally displaced by the electric motor 9, in the present invention, an actuator other than the electric motor 9 is used as the actuator for rotationally displacing the shaft 6. For example, any hydraulic or vacuum actuator may be employed.

Effects of the Invention According to the present invention, the front and rear elastic members interposed in the shaft attachment portions of the front and rear links to the vehicle body side members, respectively, have directionality of spring constant. By rotating the single shaft on which the rear link is attached, the front and rear elastic members rotate together with the shaft, thereby increasing the front and rear elasticity of the front and rear links in the load input direction. The spring constant of the member can be changed in various combinations depending on the rotation angle, the overall structure is extremely simple, the spring constant can be accurately controlled, and the elastic member The desired mechanism can be maintained for a long period of time without reducing the service life of the actuator, and since the suspension load does not directly act on the f-stage, which rotationally displaces the elastic member, in the unlikely event that the actuator Even if there is a failure in the rotation transmission mechanism leading to the shaft and the elastic member cannot be rotated, there will be almost no hindrance to running 1 aim, and this is extremely desirable from a safety perspective.
This can bring great benefits to S users.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(a) are side explanatory views and front explanatory views showing embodiments of the present invention, and FIGS. 2(a) and (O) are structural examples of elastic members used in the present invention. The front view, Figures 3 (A) and (1+), respectively, are a cross-sectional view and a front view showing a specific structural example of the support part for attaching the link to the vehicle body side member in Figure 1; Figure 54 ( A), (Iff), and (C) are front views respectively showing examples of rotation control modes of the four elastic members on the front left and right and the rear left and right that are interposed in the attachment support part of the link to the vehicle body side member. be. l... Rear wheel, 2, 3... Link, 5... Vehicle body side member, 6... Axis, 7... Elastic member, 9... Electric motor, 19... Heavy speed sensor , 20...controller. that's all

Claims (1)

[Claims] 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 via elastic members to the vehicle body side members so as to be able to swing up and down, the shaft is rotatably attached to the vehicle body side members. The front and rear elastic members are each fixed with a phase shift of 90° from each other, with a high spring constant in one direction and a low spring constant in the direction perpendicular to the spring constant. A rear suspension for an automobile, characterized in that the base ends of the front and rear links are fitted on the outer periphery so that they can rotate relative to each other, and an actuator is provided to rotate the shaft according to driving conditions. .