JPH0226722Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a rear wheel suspension used in an automobile capable of co-steering the front and rear wheels.

(Prior Art) A suspension for rear wheels in which the rear wheels can be steered is disclosed in Japanese Utility Model Application Publication No. 192773/1983.

This rear wheel suspension suspends the rear wheel using a strut with two lateral links.
A trailing arm is provided whose rear end is pivotally connected to the kingpin shaft of the strut via a rubber bushing, one lateral link is pivotally connected to the strut on the rotation center of the rear wheel, and a servo valve is attached to the other lateral link. The rear wheel steering actuator is connected to the rear wheel steering actuator, which is driven via the rear wheel steering actuator.

Further, as a rear wheel steering actuator, there is an actuator as shown in FIG. 3, which is used in a rear wheel steering device for a vehicle (Japanese Patent Application No. 15335/1982) previously filed by the present applicant.

Reference numeral 16 denotes a rear wheel steering actuator, which includes a cylindrical housing 17 and a steering rod 18 passing through the center of the housing 17, and oil chambers 17a, 1 at both ends of the housing 17.
A reaction force chamber 17c having an inner diameter larger than that of the oil chambers 17a and 17b is provided in the center of the housing 17 so as to communicate the oil chambers 17a and 17b. Free pistons 19 and 20 for receiving springs are slidably fitted into the reaction force chamber 17c, and these free pistons 1
A spring 21 is inserted between 9 and 20 in a compressed state.

The operating rod 18 has free pistons 19, 20
and spring 21, and also passes through the steering rod 1.
Pistons 18a and 18b which are slidably provided in oil chambers 17a and 17b are respectively fixed to the pistons 8, and these pistons 18a and 18b sandwich free pistons 19 and 20. Therefore, the steering rod 18 can move to the right or left only when hydraulic pressure that can push the piston 18a or piston 18b with a force exceeding the reaction force of the spring 21 is applied to the oil chamber 17a or 17b. It's becoming like that.

The oil chambers 17a and 17b of the rear wheel steering actuator 16 configured as described above include oil passages 22,
23, oil chambers 24a, 24b of a power cylinder 24 that assists in steering the front wheels are connected, respectively, and these oil chambers 24a, 24b are connected to oil passages 25, 2
6 and a control valve 27 to a pump 28 and an oil tank 29. Further, the control valve 27 connects one of the oil passages 25 and 26 to the pump 28 and the other to an oil tank 29 in accordance with the operation of the handle 30.

Here, when the handle 30 is steered to the left, for example, the oil passage 26 is communicated with the pump 28 and the oil passage 25 is communicated with the oil tank 29, so that the oil chamber 24b of the power cylinder 24 becomes high pressure, and the oil chamber 24
a becomes low pressure. As a result, power cylinder 2
4 serves to assist in steering the front wheels (not shown) to the left. At this time, the oil chambers 24a and 24b of the power cylinder 24 are connected to the oil chambers 17a and 17a of the rear wheel steering actuator 16 via the oil passages 22 and 23.
7b, the pressure in the oil chamber 17b is high and the pressure in the oil chamber 17a is low. As a result, by connecting both ends of the steering rod 18 of the rear wheel steering actuator 16 to the left and right rear wheels, the rear wheels can be steered in the right direction opposite to the front wheels.

Also, when the steering wheel 30 is steered to the right, the power cylinder 24 similarly works to assist steering the front wheels to the right, and the rear wheel steering actuator 16 steers the rear wheels in the opposite direction from the front wheels. It can be used to steer to the left.

Furthermore, the free pistons 19 and 20 are biased by the spring 21 in the actuator 16, and the rear wheels are always biased to the neutral position, so even if hydraulic pressure is not supplied from the power cylinder of the front wheels due to some failure, the rear The wheels are maintained in a neutral position, allowing the vehicle to continue moving.

(Problems to be Solved by the Invention) However, in the rear wheel suspension described in Utility Model Application Publication No. 58-192773, if the servo valve that drives the rear wheel steering actuator or its control device fails, Immediately, it becomes impossible to continue driving. Also, in the rear wheel suspension according to the earlier application, normal driving continues due to the action of the spring 21, but the spring 21 is compressed even if an excessive lateral force is applied due to unevenness of the road surface such as a rough road. It is necessary to make the spring 21 quite strong so that the rear wheels will not be steered. Therefore, it is necessary to increase the size of the rear wheel steering actuator.
It becomes necessary to significantly strengthen the support portion of the rear wheel steering actuator to the vehicle body.

In the rear wheel suspension described in Utility Model Application Publication No. 58-192773, one lateral link is pivoted to the strut at the center of rotation of the rear wheel, and most of the lateral force applied to the wheel is supported by one lateral link. However, as described in the previous application, if a large, strong spring is provided in the rear wheel steering actuator to ensure the neutral position, it will be difficult to store the spring. Therefore, the actuator becomes large, and it is difficult to make the rear wheel steering actuator sufficiently small in order to make the actuator large enough to generate the force to steer the rear wheels against a stronger spring.

(Means for solving the problem) The present invention was made to solve the above-mentioned problem, and the rear wheel is suspended by a strut having two links that support lateral force. In a rear wheel suspension in which a rear wheel steering actuator is provided on one link that has a low load sharing ratio, the rear wheel steering actuator is provided with a spring that biases the actuator to a neutral position, and the other link is provided with a spring that biases the actuator to a neutral position. It is arranged in an area surrounded by the intersection of the swing center of the upper end of the strut and the ground of a perpendicular line passing through the center of rotation of the rear wheel, and the center of action of the lateral force behind the vehicle by the maximum pneumatic rail.

(Function) The rear wheel suspension of the present invention as described above transfers most of the lateral force applied to the rear wheel to the intersection between the ground and the vertical line passing through the swing center of the upper end of the strut and the center of rotation of the rear wheel, and the maximum force. Since it is supported by the other link located in the area surrounded by the match rail and the center of action of lateral force at the rear of the vehicle, the force applied to the spring in the rear wheel steering actuator provided on one link is small and the spring is The size can be reduced, and the force required to steer the rear wheels against the spring force by the rear wheel steering actuator can also be reduced. Therefore, there is an effect that the rear wheel steering actuator can be synergistically downsized.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a plan view showing one embodiment of the rear wheel suspension of the present invention, in which 1 is an automobile body;
indicates the rear wheels, and arrow A indicates the front of the vehicle body. One end of the link 3 arranged at right angles to the longitudinal axis of the vehicle body 1 is
It is rotatably supported on the vehicle body 1 via a bush 4 made of an elastic body, and the other end of the link 3 is connected to a ball joint 5.
The lower end of the strut 7 is connected to a fixed bearing 6 which pivotally supports the rear wheel 2. The ball joint 5 is located at the strut 7 as shown in Figure 2.
The swing center B of the upper end of the rear wheel 2 and the rotation center 2a of the rear wheel 2
The line segment B-C connecting the point C where the perpendicular line intersects the ground 8, the center of action D of the lateral force applied to the rear wheels behind the vehicle by the maximum pneumatic rail from the point C, and the center of action D of the lateral force applied to the rear wheels. The range is defined by the line segment B-D connecting point B.

Here, the maximum pneumatic trail is a value obtained within the vehicle speed range in which the vehicle can travel, and is a value obtained by actual measurement.

Further, the front end of the radius slot 9 arranged in the longitudinal direction of the vehicle body 1 is rotatably supported on the vehicle body 1 via a bush 10 made of an elastic material.
The rear end of the link 3 is rotatably connected to the end of the link 3 to which the ball joint 5 is fixed via an elastic bush 11.

The bearing 6 is fixed to the lower end of the strut 7, and the upper end of the strut 7 is pivoted to the vehicle body 1 via an elastic body 12 so as to be able to swing around point B. Further, the bearing 6 rotatably supports the rear wheel 2. Further, an arm 6a is provided on the bearing 6 so as to protrude rearward, and one end of a link 13 arranged substantially parallel to the link 3 is connected to the arm 6 through a ball joint 14.
Connect to the end of a. The ball joint 14 is located behind the line segment BD, with a distance sufficiently larger than the distance between the link 3 and the line segment BD behind the link 3.

The other end of the link 13 is connected via a ball joint 15 to a steering rod 18 of a rear wheel steering actuator 16. The rear wheel steering actuator 16 is fixed to the vehicle body 1.

The actuator 16 has a built-in spring 21 similar to the actuator of Japanese Patent Application No. 59-15335, which is the earlier application mentioned above, so a detailed explanation will be omitted.

By doing as described above, in the rear wheel suspension of the present invention, most of the lateral force applied to the rear wheel is supported by the vehicle body 1 via the link 3.
Since the force applied to the rear wheel steering actuator 16 via the rear wheel steering actuator 16 becomes smaller, the rear wheel steering actuator 16 can be made smaller.

Note that since an elastic bushing 4 is interposed between the link 3 and the vehicle body 1, if a lateral force is applied to the rear wheel 2 from the outside, only the link 3 will be displaced toward the vehicle body 1. The rear wheels are in toe-in condition. This toe-in state is a favorable tendency in terms of running stability of the vehicle, so there is no problem.

(Effect of the invention) Thus, when the rear wheel suspension of the present invention is provided with a rear wheel steering actuator that has a built-in spring for maintaining the neutral position, the spring for maintaining the neutral position can be made small, and thereby In addition, the force for the rear wheel steering actuator to steer the rear wheels against the spring can also be reduced, so the rear wheel steering actuator can be synergistically miniaturized. Further, there is no need to particularly strengthen the support portion for attaching this rear wheel steering actuator to the vehicle body. Therefore,
The rear wheel suspension of the present invention has the excellent effect of not impairing the running stability of the vehicle, although it is small and lightweight.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the rear wheel suspension of the present invention with the strut removed, FIG. 2 is a side view thereof, and FIG. 3 is a schematic plan view showing the rear wheel steering actuator of the prior application. 1...Vehicle body, 2...Rear wheel, 2a...Rotation center,
3,13...Link, 4,10,11...Button, 5,14,15...Ball joint, 6...
...Bearing, 6a...Arm, 7...Strut,
8... Ground, 9... Radius slot, 12... Elastic body, 16... Rear wheel steering actuator, 18
...Steering rod.

Claims (1)

[Scope of utility model registration request] In a rear wheel suspension, the rear wheel is suspended by a strut having two links that support lateral force, and an actuator for rear wheel steering is provided on one of the two links, which has a smaller internal load sharing ratio. The steering actuator is provided with a spring that urges the actuator to the neutral position, and the other link is connected to the intersection of the ground and the perpendicular line passing through the swing center of the upper end of the strut and the center of rotation of the rear wheel and the maximum pneumatic rail. A rear wheel suspension characterized by being disposed within an area surrounded by a center of action of lateral force at the rear of the vehicle.