JPS6316281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle suspension having a shock absorber.

As a damping force adjusting device for a shock absorber, for example, there is a device shown in FIG. 1 (Utility Application No. 1983-8394, previously filed by the present applicant).

In the figure, 1 is a vehicle such as an automobile, 2 and 3 are front wheels and rear wheels of the vehicle 1, 4 and 5 are hydraulic shock absorbers provided in the suspension of each wheel 2 and 3, and 6 is an engine. A sensor 7 detects the speed of the vehicle 1, and the shock absorber 5 is electronically controlled by a control signal from a control circuit 8 output based on the speed detected by the sensor 7.

The device shown in Fig. 1 detects the vehicle speed with a sensor 7, and when the vehicle speed is low, the damping force of the shock absorber 5 of the rear wheel 3 is set to be relatively higher than that of the front wheel, thereby improving turning performance. While achieving excellent neutral steering, the damping force of the rear wheel shock absorber 5 is controlled to be lower relative to the front wheel side by the above-mentioned control device above a certain vehicle speed, resulting in excellent stability at high speeds. The purpose is to obtain understeer characteristics and improve maneuverability.

Further, there are those shown in US Pat. No. 4,030,580 and No. 3,995,883 aimed at improving riding comfort.

However, since these conventional shock absorbers are designed to improve ride comfort or the lateral motion characteristics of the vehicle, the roll angle caused by the centripetal acceleration caused by the start of a turn increases when the steering wheel is turned. You cannot reduce the speed at which you move (roll rate). For this reason, there was a limit to the reduction of the shock absorber's damping force, which is necessary to improve ride comfort, and if the damping force was set too low, the occupants would feel a sudden lateral shake, which would make them uncomfortable. .

This invention was made by focusing on such conventional problems, and includes a steering sensor that emits a signal corresponding to the steering angle of the steered wheels when steering the steering wheel, and a steering sensor that responds to the steering angular velocity based on the signal from this steering sensor. a steering angle calculator that emits a signal corresponding to the running speed of the vehicle; a vehicle speed sensor that emits a signal that corresponds to the running speed of the vehicle; and signals from the steering angular velocity calculator and the vehicle speed sensor are input to respond to changes in centripetal acceleration when the vehicle turns. The object of the present invention is to improve the riding comfort of a vehicle by detecting a condition in which a roll speed exceeding a predetermined value occurs and thereby increasing the damping force of the shock absorber to prevent the occurrence of a roll speed exceeding a predetermined value.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 5.

First, the configuration will be described. Reference numerals 2 and 3 are front wheels and rear wheels of the vehicle 1, and 4 and 5 are shock absorbers provided on each wheel 2 and 3. 6 is the engine,
Sensor 7 detects vehicle speed, and sensor 9
Detects the steering angle or the steering angular velocity of the vehicle 1, or both. and control circuit 8
is based on the input from sensor 7 and sensor 9,
This is a control circuit for detecting a condition where a roll speed equal to or higher than a predetermined value corresponding to centripetal acceleration when a vehicle turns occurs.

FIG. 3 shows the internal structure of the shock absorbers 4 and 5, where 10 is a cylinder consisting of inner and outer cylinders 11 and 12, and 13 is a rod-shaped piston that moves within the cylinder 10. A damping force generating bottom valve 14 is provided at the bottom of the cylinder 10, which includes a compression side damping force generating orifice 15, a rebound side damping force generating orifice 16, and a non-return valve 17.
By working together, resistance is provided to the oil flow in the oil chambers A and B, and a damping force is generated. A damping force generating main valve 18 is provided at the lower end of the piston 13, and the damping force generating orifices 19, 20 on the compression side and the expansion side and the non-return valve 21 work together to distribute the oil between the oil chambers B and C. It is designed to provide resistance to flow and generate damping force. 22 is an oil seal, and 23 is a cap.

Further, the piston 13 is formed by an upper piston 24 and a lower piston 25 which are divided in the axial direction, and the lower piston 25 is provided with a bypass passage 26 that bypasses the damping force generating main valve 18 and directly communicates the oil chambers B and C. On the other hand, an actuator 27 having a solenoid 28 and a plunger 29 is installed inside the upper piston 24. Furthermore, the plunger 29 is connected to the bypass passage 2.
6, the actuator 27 operates the plunger 29 depending on whether the solenoid 28 is energized or de-energized, opens and closes the bypass passage 26, and directly communicates the oil chambers B and C. 30 is a return spring, 31 is a leader wire, and 32 is a filler.

FIG. 4 shows an example of the electric circuit of the device of the present invention. In this case, the signals from the vehicle speed sensor 7 and the steering sensor 9 are input to the control circuit 8, and when the respective conditions are met, the output is output. , this output causes solenoid 2 of the shock absorber in Fig.
8 to operate the plunger 29, the bypass passage 26 is closed and the damping force of the shock absorber is increased.

Next, the action will be explained.

When the steering wheel is not turned or when the vehicle speed is zero, at least one of the input signals to the control circuit 8 (output signals θ, v of the sensors 7 and 9) is zero, and in FIG. 4, aθ=0<α, bθ〓 =0<α or dv=
0<β. Therefore, the output signal from the control circuit 8 is also zero, and the solenoid 28 of the plunger 29 of the shock absorbers 4 and 5 is not energized.
The bypass passage 26 is open, and the damping force of the shock absorbers 4 and 5 is kept low to provide good riding comfort. When you turn the steering wheel,
The input signal θ from the steering sensor 9 to the control circuit 8 is combined with the signal v from the vehicle speed sensor 7 within the control circuit 8,
In Fig. 4, when dv≧β, aθ≧α or
When steering is performed such that bθ〓≧α, a valid output signal such as , is generated. When even one of these output signals is generated, the solenoid 28 of the plunger 29 in the outer wheel side shock absorber or the four-wheel shock absorber is energized via an amplifier (not shown), and as a result, the plunger 29 is It is pushed out against the force of the spring 30 and closes the bypass passage 26. Therefore, all the oil flowing between the oil chambers B and C passes through the damping force generating main valve 18. Therefore, the damping force increases and it is possible to prevent the vehicle from rolling due to centripetal acceleration during turning. Therefore, according to the device of the present invention, it is possible to use a shock absorber with a low damping force setting that provides good riding comfort when the steering wheel is not being steered, and to reduce the rolling speed of the vehicle when the steering wheel is being steered. Can be done.

In other words, the output signal is determined when the steering angle θ or the steering angular velocity θ is made greater than a predetermined value (aθ≧α or bθ〓≧α) when the vehicle travel speed dv≧β is greater than or equal to a predetermined value (aθ≧α or bθ≧α), respectively. It is determined that the roll speed is high during steering in the _E1 region or the _E2 region, which are shown with reverse hatching, and the damping force of the shock absorber is increased to reduce the roll speed of the vehicle. However, since the roll speed is slow in the other region D in FIG. 6, the damping force is kept low to ensure ride comfort. Note that the output signal has the effect of increasing the damping force while the vehicle turns while the steering angle remains constant, and the output signal prevents the roll speed from exceeding a predetermined value when the steering angular speed is high even if the steering angle is small. It is possible.

In addition, the output signal is
When dv≧β, the roll speed is determined to be high during steering when the value c (aθ+bθ〓) corresponding to the sum of the steering angle and the steering angular velocity is greater than or equal to a predetermined value α, that is, during steering in the G region shown in FIG. This increases the damping force of the absorber and reduces the roll speed. However, in the other region F, the roll speed is slow, so the damping force is kept low to ensure ride comfort. Note that even if only one of aθ and bθ〓 is large, it is difficult to increase the damping force, so that the damping force is not increased unnecessarily.

Figure 5 shows an example of an electric circuit for increasing the damping force of the shock absorber of the wheel on the opposite side to the steering direction.This is a comparator that does not output when the steering sensor is in neutral but outputs when turning to the right. 33
A comparator 34 that outputs when turning left is added to the circuit shown in Fig. 4, and an AND circuit and an amplifier circuit are used to generate an output that operates the left shock absorbers 4 and 5, and an output that operates the right shock absorbers 4 and 5. The output shall be obtained.

That is, in this case, since the control circuit has a circuit for determining the steering direction, when turning to the right, it outputs an output signal and attaches the solenoids 28 of the shock absorbers 4 and 5 provided on the front and rear wheels on the left side of the vehicle. By forcing the bypass passage 26 to close, the left shock absorber 4, which is on the outside of the turn,
When turning left, an output signal is output to increase the damping force of the shock absorbers 4 and 5 on the right side of the vehicle.

In this way, by increasing the damping force of the shock absorbers of the front and rear wheels on only one side of the vehicle during steering, the deterioration of ride comfort caused by increasing the damping force can be reduced, and the roll speed of the vehicle can be reduced to a small value. can be kept.

In this embodiment, the damping force on the contraction side of the shock absorber on the opposite side to the steering direction is increased. However, since the shock absorber has a higher damping force on the extension side, the shock absorber on the same side as the steering direction is increased. Needless to say, the damping force on the extension side of the absorber may be increased.

As explained above, according to this invention,
When the steering wheel is not being steered, a shock absorber with a low damping force setting provides a good ride.
When the steering wheel is turned, the damping force of the shock absorber increases, so that an effect can be obtained in that the rolling speed of the vehicle can be prevented from becoming excessive.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional shock absorber damping force adjustment device, FIG. 2 is a perspective view of the device of the present invention,
Fig. 3 is a longitudinal sectional view of the shock absorber, Fig. 4 is a circuit diagram showing an example of the electric circuit of the device of the present invention, Fig. 5 is a diagram of another embodiment, and Figs. 6 and 7 are explanatory diagrams of the operation. It is. 1...Vehicle, 2...Front wheel, 3...Rear wheel, 4,5
...Shock absorber, 6...Engine, 7...
...Vehicle speed sensor, 8...Control circuit, 9...Steering sensor.

Claims (1)

[Scope of Claims] 1. In a vehicle suspension in which at least one of the front wheels and the rear wheels is equipped with a shock absorber having a built-in valve device that inputs an external electric signal to vary the damping force, the steering wheel A steering sensor that emits a signal corresponding to the steering angle, a steering angular velocity calculator that emits a signal corresponding to the steering angular velocity based on the signal from the steering sensor, a vehicle speed sensor that emits a signal corresponding to the traveling speed of the vehicle, and these steering angular velocities. A control circuit receives signals from an arithmetic unit and a vehicle speed sensor, detects a condition in which a roll speed of a predetermined value or higher corresponding to a change in centripetal acceleration occurs when the vehicle turns, and issues a signal to operate the valve device; A suspension for a vehicle, characterized in that the ride comfort of the vehicle is improved by increasing the damping force of the shock absorber through the operation of the valve device to prevent the roll speed from exceeding a predetermined value. 2. The vehicle suspension according to claim 1, wherein the control circuit includes a circuit for determining the steering direction, and emits a signal to operate a valve device of a shock absorber provided in the front and rear wheels on one side of the vehicle. Shion. 3. In a vehicle suspension in which at least one of the front wheels or the rear wheels is equipped with a shock absorber having a built-in valve device that changes the damping force by inputting an external electric signal, a signal corresponding to the steering angle of the steered wheel is provided. a steering sensor that emits a signal, a steering angular velocity calculator that emits a signal corresponding to the steering angular velocity based on a signal from the steering sensor, a vehicle speed sensor that emits a signal that corresponds to the traveling speed of the vehicle, these steering sensors, the steering angular velocity calculator, and A signal from a vehicle speed sensor is input to detect a condition in which a roll speed of a predetermined value or more corresponds to a change in centripetal acceleration when the vehicle turns, which is comprised of a steering angle, a steering angular velocity, and a signal indicating a traveling speed of the vehicle of a predetermined value or more. and a control circuit that issues a signal to actuate the valve device, and the actuation of the valve device increases the damping force of the shock absorber to prevent the roll speed from exceeding a predetermined value, thereby improving the ride comfort of the vehicle. A vehicle suspension characterized by: 4. The vehicle suspension according to claim 3, wherein the steering angle and the steering angular velocity are each compared with separately determined predetermined values. 5. The vehicle suspension according to claim 3 or 4, wherein the value corresponding to the sum of the steering angle and the steering angular velocity is compared with a predetermined value. 6. Claims 3 to 5, wherein the control circuit includes a circuit for determining the steering direction, and generates a signal to operate a valve device of a shock absorber provided in the front and rear wheels on one side of the vehicle. A suspension for a vehicle as described in any of the above.