JPH0620803B2 - Car suspension - Google Patents

Description

The present invention relates to automotive suspension.

The suspension device of the vehicle supports the weight of the vehicle,
It has the role of buffering irregularities in the road surface, and of course not only the riding comfort,
Pitching and rolling during driving, as well as stability and responsiveness during turning, are seriously affected. Therefore, it is desirable that the characteristics of the suspension of the front and rear wheels of the automobile can be appropriately changed so that the movement characteristics can be variously changed. For example, the actual exploitation 56-147107
In Japanese Patent Laid-Open No. 55-65741, a control for increasing the damping force of all the shock absorbers by detecting the roll speed (roll angle change rate) using a steering sensor for detecting a change in steering angle and a vehicle speed sensor. There has been proposed a device that prevents the roll speed at the time of turning from exceeding a predetermined value by controlling the hardware. According to this device, the roll speed becomes slower at the time of turning, and it is possible to achieve both the longitudinal performance and the improvement of riding comfort, but it is possible to reduce the roll angle itself, that is, the roll angle change amount, only by controlling the shock absorber. I can't.

On the other hand, in order to reduce the roll angle change amount, a spring force variable spring is provided in parallel with the damper of the shock absorber as shown in Japanese Utility Model Laid-Open No. 56-39311, and the spring force of this spring is strengthened. It is possible to control. Further, at the same time, in order to make the damping force of the damper variable, the damper described above is used.
The damping force variable damper shown in No. 107 etc. may be used.

However, in this way, using the variable spring and variable damper,
If both are switched to hard or soft at the same time, the driving stability and the riding comfort change suddenly, which is not desirable.

It is therefore an object of the present invention to provide a suspension in which the entire suspension is not switched to soft or hard so that steering stability and riding comfort do not suddenly change.

A vehicle suspension according to the present invention is a vehicle suspension including a damping force variable damper for suspending a vehicle wheel on a vehicle body and a spring force variable spring, and a damping force adjusted to increase the damping force of the variable damper. Adjusting means, spring force adjusting means for adjusting to increase the spring force of the variable spring, electric signal generating means for outputting an electric signal that is a function of any one of a roll angle, a pitch angle and a browsing amount of an automobile, An electric signal is received from the signal generating means, and when the electric signal is larger than a predetermined first set value and smaller than a second set value which is larger than the first set value, an actuation signal for increasing the damping force adjusting means. On the other hand, when the electric signal is larger than the second set value, both the damping force adjusting means and the spring force adjusting means are output. Characterized in that it comprises a control means for outputting an operation signal to Mel so.

That is, in the present invention, if any one of the roll angle, the pitch angle, and the amount of browsing changes moderately from the state where the spring and the damper are softly set, only the damper is made hard, and the high degree is set. If it is changing, both the spring and damper are set to hard, so it is possible to prevent a sudden change in suspension characteristics from soft to hard, and at the same time, to improve ride comfort and control at a high level. It is possible to achieve both stability and stability.

In other words, if any one of the roll angle, pitch angle, and amount of bowing changes moderately, only the damper will be hard, and the suspension will be harder than if both the spring and damper were hard. It can be prevented from passing and the ride quality can be maintained. Furthermore, steering stability can be improved more than when both the spring and the damper are softly set.

Furthermore, if only the spring is made hard, the riding comfort will be the same as if only the damper were made hard, but the damping capacity of the damper will not reach the repulsive force of the spring, making the vehicle easily vibrating and changing the road surface. It reacts sensitively to the driver's operation and causes pitching and browsing. That is, when only the spring is made hard, the steering stability becomes worse than when only the damper is made hard. In the present invention, since only the damper is made hard, it is possible to slow the roll of the vehicle while maintaining the riding comfort, and to prevent pitching and browsing which adversely affect the steering stability.

Hereinafter, a suspension of an automobile according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing suspension of an automobile according to an embodiment of the present invention, and FIG. 2 is a system diagram of main parts thereof.

A front wheel suspension 1 and a rear wheel suspension 2 are provided in association with the front and rear wheels, respectively. The suspensions 1 and 2 are respectively springs 3
a, 4a and oleo dampers 3b, 4b, shock absorbers 3, 4 are provided, and air springs 5, 6 constituted by a diaphragm made of a suitable elastic material are provided around the dampers 3b, 4b. There is. The dampers 3b, 4
Reference numeral b is a variable damper whose damping force is adjustable, and therefore the orifice provided on the piston (not shown) has a variable diameter. Plungers (not shown) driven by solenoids 7 and 8 are provided in the piston rods 3c and 4c in order to change the diameter of the orifice, and the plungers are rotated by the excited solenoids 7 and 8. Thus, the diameter of the orifice is reduced, the damping force of the dampers 3b and 4b is increased, and the suspension characteristics of the suspensions 1 and 2 are made hard. The air springs 5 and 6 are connected to the control air chambers 11 and 12 by air pipes 9 and 10, respectively,
The air springs 5 and 6 and the air chamber 11 are operated by the operation of the solenoid valves 13 and 14 provided at the inlets of the chambers 11 and 12.
The communication state between 12 is controlled. In this example, when the solenoids of the solenoid valves 13 and 14 are excited, the communication is cut off. In this way, the air springs 5 and 6 and the air chamber 1
When the communication between 1 and 12 is cut off, the air springs 5 and 6
Since the effective volume of the air chamber is reduced, the spring force of the air springs 5 and 6 becomes strong, and the suspension characteristics of the suspensions 1 and 2 become hard.

A controller 15 excites the solenoids 7 and 8 for adjusting the damping force of the variable dampers 3b and 4b and the solenoid valves 13 and 14 for adjusting the spring force of the air springs 5 and 6. The controller 15 is connected to a roll sensor 16 that detects the amount of change in the attitude of the automobile to detect a roll and outputs a roll signal S _θ indicating the roll amount. Controller 1
5 includes first and second comparators 17 and 18, as shown in FIG. 3, and one input end of the first and second comparators 17 and 18 is connected to the roll sensor 16. The roll sensor 16 is connected to the output terminal, and the roll signal S _θ is input from the roll sensor 16. First and second reference voltage generators 19 and 20 are connected to the other input ends of the first and second comparators, respectively. The first reference voltage generator 19 is adapted to generate a voltage V1 larger than the voltage V2 generated by the second reference voltage generator 20.
The output terminals of the first and second comparators 17 and 18 are connected to first and second switching transistors 21 and 22 for controlling on / off of the supply of current to the solenoid valves 13 and 14 and the solenoids 7 and 8, respectively. It is connected.
In the controller 15 having the above configuration, V2 <S _θ <V
When it is 1, only the second comparator 18 outputs the Hi signal, and accordingly only the second transistor 22 is turned on, so that only the solenoids 7 and 8 are excited and only the damping force of the damper is strengthened. On the other hand, when V2 <V1 <S _θ , the Hi signal is output from both the first and second comparators 17 and 18. Accordingly, the first and second transistors 21, 2
Since both 2 are turned on, the solenoid valves 13, 14 as well as the solenoids 7, 8 are powered, thus making both the damper and the spring hard.

In the above description, the damper and the spring are controlled according to the state of the roll, but similar control may be performed at the time of starting or braking. Also,
Of course, instead of hardening the damper first, the spring may be hardened first.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a suspension of an automobile according to an embodiment of the present invention, FIG. 2 is a system diagram of a main part of the suspension shown in FIG. 1, and FIG. 3 is FIG. 6 is a circuit diagram showing an electronic control system of the suspension shown in FIG. 1, 2 ... Suspension, 3b, 4b ... Oreo damper, 5, 6 ... Air spring, 7, 8 ... Solenoid, 1
3, 14 ... Solenoid valve, 15 ... Controller, 16 ... Roll sensor.

Claims (1)

[Claims] 1. A suspension of an automobile including a damping force variable damper for suspending a vehicle wheel on a vehicle body and a spring force variable spring, wherein damping force adjusting means for adjusting the damping force of the variable damper to increase. A spring force adjusting means for adjusting the spring force of the variable spring, an electric signal generating means for outputting an electric signal which is a function of any one of the roll angle, the pitch angle and the amount of browsing of the automobile, and the electric signal generating means. The electric signal is larger than the predetermined first set value and smaller than the second set value larger than the first set value, the actuating signal is output to increase the damping force adjusting means. , When the electric signal is larger than a second set value, an actuation signal is output so as to increase both the damping force adjusting means and the spring force adjusting means. Automotive suspension equipped with a control unit that.