JPS59190015A - Vehicle suspension control device - Google Patents

Abstract

PURPOSE:To enhance the stability of an off-road vehicle upon running at a high speed with the use of a suspension control device, by providing such an arrangement that a selector valve and an accumulator are incorporated in the suspension control device, and therefore, a logic valve arranged in parallel with a restrictor valve is opened and closed in association with vehicle oscillation characteristic signals. CONSTITUTION:A hydraulic pressure in an oil chamber 8 in a hydraulic cylinder 6 is increased by the push-up of a travel means 1, and therefore, oil from the oil chamber 8 flows into an accumulator 11 through a restrictor valve 9. At this time detection signals from a vehicle body pitch rate gyro and a vehicle body vertical accelerometer which are not shown are delivered as oscillation characteristic signals 17 to a selector valve 18 which is therefore changed over into a position 18b. With this arrangement oil in the oil chamber 8 flows into the accumulator 11 through a logic valve 17 to reduce the damping characteristics, and therefore, shocks exerted to the vehicle body is damped. If the vehicle body pitches down, the position of the selector valve 18 is changed to a position 18a to increase the damping force. Thereby, the stability of the vehicle body and as well the comfortability thereof may be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle suspension control system suitable for driving under adverse conditions such as uneven ground and sloped ground.

In conventional vehicles traveling on rough terrain, for example, as shown in the first diagram, a suspension system f constituted by a hydraulic cylinder e is used to support a vehicle body g, for each of a plurality of vehicle traveling means C, such as wheel wheels that engage and rotate with rollers a. One that is suspended is known. In this case, the oil chamber of the hydraulic cylinder e is throttled by the valve 1 and the I parallel to it.
J IJ-7 It is connected to the accumulator 1 sealed with gas through the valve j, and the traveling means C is
When the pressure in the oil chamber rises due to an impact, fluid is caused to flow into the accumulator 1 through the throttle valve, causing the hydraulic cylinder θ to perform a buffering action, and when the impact is removed, the throttle valve increases. Generally, the fluid is returned to the Ws chamber from the accumulator 1 through the valve m and the check valve n, and the valve m and the check valve n are returned to their original state while undergoing damped vibration.

In such a device, the fluid flowing from the oil chamber hill due to the impact is restricted by the fixed throttle valve j-, and the damping force is
As shown in the figure, only one type of change can be obtained that increases with the operating speed, which has the disadvantage of poor riding comfort.Also, if the throttle valve is set large, the damping force will be reduced and the shock mitigation property will be improved, but the damping time will be This results in increased rolling and pitching of the vehicle body, and the drawback that the vehicle body cannot be stabilized at high speeds.

The present invention aims to solve these drawbacks, and the first invention is to suspend a vehicle body on wheels or other vehicle traveling means via a hydraulic cylinder, and to apply the hydraulic pressure of the hydraulic cylinder to an accumulator via a throttle valve. In the type of hydraulic cylinder that exerts a buffering effect by connecting to the throttle valve, a logic valve is provided in parallel with the throttle valve, and the pressure chamber of the logic valve is controlled by a vibration characteristic signal of the vehicle body. The second invention is characterized in that the logic valve is selectively connected to the accumulator to allow the logic valve to open and to the oil chamber to maintain the logic valve closed through an actuated switching valve. The vibration characteristic signal is obtained from calculated values of a pitch angular velocity signal, a four wheel angular velocity signal, and a vertical acceleration signal of the vehicle body. It is characterized by being composed of two valves.

The third embodiment of the present invention will be described with reference to the attached drawings.
In the figures and FIG. 4, (1) indicates a vehicle running means consisting of wheels (3) rotating a crawler (2), and (4) indicates a vehicle body. ) to the left and right of the arm (
4a) and a piston (7) of a hydraulic cylinder (6) attached to the vehicle body (41) via a rod (5).
connected to. The oil chamber (8) of the piston (7) is a valve unit equipped with a throttle valve (9) as shown in FIG.
(Connected to, for example, an accumulator circle filled with gas via 101. Mutsu α3) is a relief valve and a check valve provided in parallel with the throttle valve (9), and the relief valve θ2 is connected to the cylinder (6). ) is activated when the pressure in the oil chamber (8) of the check valve (8) becomes higher than the set pressure, and allows fluid to flow through the valve.

The above configuration is not particularly different from the conventional one, but in the present invention, a logic valve (one group) having a differential seat type valve configuration is provided in parallel with the throttle valve (9), and its pressure chamber is (
10 is connected to a switching valve (181) that switches υ according to the vehicle body vibration characteristic signal 071, and the switching valve θ~ is in the position @ (18a
) or (18b), the pressure chamber (16) is connected to the accumulator (11) or the accumulator aυ so that the logic valve θ can be opened by the high pressure of the hydraulic cylinder (6). At high pressure, the logic valve (the pressure chamber α6) closes, and the oil chamber (8) of the hydraulic cylinder (6) closes.
) is now selectively connected.

To further explain this, the switching valve (181 is in position (18
a), when the pressure in the oil chamber (8) of the hydraulic cylinder (6) increases, that is, when the traveling means +11 receives an impact, the oil chamber (
Since the high pressure of 8) acts on the logic valve (pressure chamber 06 of 15J), the logic valve Q5) remains in the closed state, and the oil chamber (
Similar to the conventional system, the high-pressure fluid in step 8) is transferred to the accumulator (
1υ, and if the flow rate is large, the pressure in the oil chamber (8) becomes high, so the accumulator (
It flows into ID. When the impact decreases, the pressure in the oil chamber (8) decreases, so the pressure from the accumulator συ to the throttle or valve (1) decreases.
4) and the check valve (131), the flow rate moves to the oil chamber (8), and the operation of the piston (7) stops when the pressure in the core oil chamber (8) and the accumulator (11) become the same pressure. However, a large damping force is obtained in the cylinder (6).

- When the changeover valve (18) is in position lid (18b), if the flow rate from the oil chamber (8) is small, it will flow to the accumulator 01) via the throttle valve (9), but if it increases to some extent, it will flow to the pressure chamber ( The logic valve (151) into which the low pressure of the accumulator (1]) is introduced into 1G) is opened by the pressure of the oil chamber (8), and the pressure of the oil chamber (8) and the accumulator (11) is increased through the valve (151). Equal di, cylinder (6)
Fluid flows in the trench where the operation stops. When the number of surgical areas decreases, the pressure in the oil chamber (8) of the cylinder (6) decreases, so the pressure is increased from the high-pressure accumulator (old) to the oil chamber (8) through the throttle valve a (a) and the check valve (13). When the fluid returns to 81 and the piston (by pushing the sword back) and the oil chamber (8) become the same pressure, the piston (7) will stop.
In this case, the open fluid between the oil chamber (8) and the accumulator (11) can easily circulate, so that a small damping force can be obtained in the cylinder (6).

This change in damping force is as shown in Figure 5.
When ~ is at position 1if (18a), there will be a large damping force as shown by curve A, and when ~ is at position (18b), there will be a large damping force as shown by curve B.
This results in a low damping force as shown in .

The oscillation characteristic signal θη inputted to the switching valve Q81 is generated by a vehicle oscillation detection device (
It is obtained by arithmetic processing in the entire signal processing device (1). Each signal obtained via the demodulator (24) and the integrator (25) is processed by the weighting function processor (26), and the drive circuit (2η) of the switching valve 08) is configured with a comparator. (2) The process of adding each signal in the adder C0 connected through δ is considered to be scary.(30) is a manual changeover switch for manually operating the changeover valve α mark; (3]) (3(6) C3J indicates power supply money.

Car body pitch rate gyro (2υ outputs a pitch angular velocity signal according to the pitching of the car body (4), car body roll rate gyro (2υ outputs a roll angular velocity signal according to the rolling of the car body (4), and also outputs a roll angular velocity signal according to the rolling of the car body (4), and Accelerometer (2
3) outputs an acceleration signal for the vertical movement of the vehicle body (4), and these detected values are changed in the weighting function processor (26), and the changed one or more signals are sent to the adder.
The calculation process is carried out in . This calculated value is compared with the input from the reference device (3 functions) by a comparator (28), and the comparison value is input to the drive circuit (27) for the switching valve with a 0 mark.The comparator (28)
It is preferable that the reference device G is provided with a dead zone element and that an appropriate dead zone can be set by adjusting the input from the reference device G.

In addition, five traveling means (1) are provided on the left and right sides of the vehicle body (4), and a logic valve (lω) is installed in each hydraulic cylinder (6).
and a switching valve 081, the sixth
As shown in the figure, each switching valve (181) (18a) (18b) controls the suspension from the front to the rear on the right side of the vehicle body (4).
) (18c) (18d) (18e), and each switching valve 08 that controls suspension from the front to the rear on the left side is respectively (18f).
(1sω(18h)(1a1)(18j) When tossed, the pitch angular velocity signal from the car body pitch rate gyro (21) is transferred to the switching valve (1) that controls the rear left and right suspension of the car body (4).
8c) (18d) (18e) (j8h) (181) (1
8j) has switching valves (18a) (18b) that control the front left and right suspension by a code converter (3!il (support)) C371.
221
The roll angular velocity signal from the left switching valve (18f)
The signals are inputted to the code converter end as signals having opposite signs to those of the switching valves (18a) to (18e) on the right side.

Vehicle body vibration characteristic signal characteristic m′ output from the signal processing device
@aη can be used as a signal to configure the throttle valve (9) interposed in the circuit from the oil chamber (8) of the hydraulic cylinder (6) to the accumulator αυ as a variable throttle valve and change its throttle area. In this case, the damping force curves A and B shown in FIG.

In this case, the variable throttle valve (9) fully automatic controller) T=I-
LaO! From control by signal θ force via 1 to control 1 by manual controller (41) to switch (4υ(4
It is preferable that the switch be made freely switchable by the switch 21.

The operation is performed on a vehicle traveling on flat land, and the vehicle body (
The vehicle having a plurality of vehicle traveling means (1) on the left and right sides of 4) will be described as follows.

Now, when the vehicle encounters a protruding obstacle, the vehicle traveling means (1) in front of the vehicle body (4) is pushed up, and the vehicle body (4) is moved to a pitch where the front of the vehicle body (4) is lifted up via the hydraulic cylinder (6). It will be in an up state. At the same time as this push-up, the oil chamber (8) of the traveling means (hydraulic cylinder (6) of 1, 1) that ran over the obstacle becomes high pressure, and the oil flows to the accumulator 01 through the throttle valve (9). At this time, the vehicle pitch rate gyro (2I) and vehicle vertical accelerometer (23) measure the pitching and vertical conditions of the vehicle body. When e-catching occurs, a lateral signal is output, and the oscillation characteristic signal 07) is input to the switching valve (I81), it is switched to position (18b).

Therefore, the fluid in the oil chamber (8J) can flow into the logic valve (old accumulator via 151') which operates as a relief valve, resulting in a small damping force characteristic as shown by curve B in Fig. 4, and the vehicle body +41 In addition, in this case, the traveling means (4) at the rear of the vehicle body (4)
1), since the oscillation characteristic signal a71 is not input to the logic valve (I51 switching valve), it is controlled to a large damping force characteristic by the throttle valve (9), and as the vehicle body (4) pitches up, the vehicle body The rear part of the vehicle (4) can be prevented from sinking, and the pitching of the vehicle body (4) when it runs over an obstacle can be reduced.

When the vehicle body (4) crosses an obstacle and pitches down forward, the hydraulic cylinder (6) of the vehicle body (4J's forward traveling means (I+) moves to the switching valve α position (18a), causing a large The cylinder (6) of the rear traveling means (1) running over an obstacle is controlled to a small damping force characteristic by the signal θ force, and pitching is reduced.

If the running means on either the left or right side of the vehicle body (4) runs into an obstacle and the vehicle body (4) tilts, each running element (12) on the negative side runs over the obstacle and the vehicle body (4) tilts. , each hydraulic cylinder (6) of each traveling means on the negative side is controlled to a small reducing force characteristic by a signal generated by the roll rate gyro (2) of the vehicle body, and at the same time, the hydraulic cylinders of each traveling means on the other side are controlled to a large damping force. The force characteristics are controlled, and thus the vehicle body (4) receives a moderate S impact, and the vehicle body (4) on the other side can be prevented from washing, allowing the vehicle to travel in a stable posture with little rolling.

When driving on a flat road with no obstacles, the logic valve α5) is closed because there is no vibration characteristic signal 07) input to the switching valve α, and each cylinder (6) is controlled to have a large damping force characteristic, so the vehicle can run at high speed. can be done.

When the logic valve (151) is closed and fluid flows from the oil chamber (8) to the old actuator, the operating speed of the piston (7) of the cylinder (6) is high and even when a large flow rate flows, a constant flow occurs. The damping force can be controlled to be stable, and the disadvantage of increasing the damping force due to an increase in the operating speed of the piston, which occurs when conventional control is performed using only a throttle, can be eliminated.

Further, if the throttle valve (9) is constructed as a variable throttle valve and the vibration characteristic signal ση is inputted to the throttle valve to throttle the throttle valve, even better damping force characteristics can be controlled, and the impact mitigation performance can be increased.

In this way, according to the present invention, a logic valve is provided in parallel with the throttle valve in the circuit from the oil chamber of the hydraulic cylinder that suspends the vehicle body to the accumulator, and the pressure chamber is actuated by the vibration characteristic signal of the vehicle body to connect the accumulator and the oil chamber. Since the opening and closing of the logic valve is controlled by the pressure of the oil chamber, the damping force of the hydraulic cylinder is changed in size according to the vibration of the vehicle body, thereby suppressing the vibration of the vehicle body. be able to. According to the second invention, the vehicle body vibration characteristic signal for operating the switching valve is obtained from the calculated values of the vehicle body's pitch angular velocity signal, roll angular velocity signal, and vertical acceleration signal. By controlling the damping force of the hydraulic cylinder, it is possible to further improve the stability of the vehicle body and the ride comfort. Furthermore, according to the third aspect of the invention, since the throttle valve through which fluid flows from the oil chamber to the accumulator is controlled by the vibration characteristic signal, the damping force characteristics of the hydraulic cylinder can be varied more widely, and the vibration of the vehicle body can be varied. There are effects such as being able to be more adapted to the situation.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the conventional example, Fig. 2 is its damping force characteristic curve diagram, Fig. 3 is a cut side view of the embodiment of the present invention, Fig. 4 is a diagram of its main parts, Fig. 5 is its damping force characteristic curve diagram, No. 6
The figure is a diagram of a processing device for oscillation characteristic signals. (1) Vehicle traveling means (4) Vehicle
Body (6)...Hydraulic cylinder (8)...Oil
Pressure (9)... Throttle valve old]...
・Accumulator 051...Logic valve (
16)...Pressure Palm surface...Sway characteristic signal (
18) Switching valve patent applicant Director of the Technology Research Headquarters, Defense Agency

Claims (1)

[Scope of Claims] 1. A vehicle body is suspended on wheels or other vehicle running means via a hydraulic cylinder, and the hydraulic cylinder is connected to an accumulator via an oil chamber full throttle valve to provide a buffering effect to the hydraulic cylinder. In the type that reduces the flow rate, a logic valve is provided in parallel with the throttle valve, and the pressure reed of the logic valve is
It is characterized by being selectively connected to the accumulator to allow the logic valve to open and to the oil chamber to maintain the logic valve closed via a switching valve operated by a vehicle body vibration characteristic signal. Vehicle suspension control system. 2. By suspending the vehicle body on wheels or other vehicle running means via a hydraulic cylinder, and connecting the oil chamber of the hydraulic cylinder to an accumulator via a throttle valve, the hydraulic cylinder does not have a buffering effect. In the type with which the throttle valve is connected, a logic valve is provided in parallel with the throttle valve, and the pressure chamber of the logic valve is
selectively connected to an accumulator to allow the logic valve to open and to a nuclear oil chamber to maintain the logic valve closed via a switching valve that moves according to a vehicle body vibration characteristic signal; , the vibration characteristic signal is a pitch angular velocity signal of the vehicle body. A vehicle suspension control device characterized in that a roll angular velocity signal and a vertical acceleration signal are obtained from calculated values. (v) A system in which the vehicle body is suspended on wheels or other vehicle running means via a hydraulic cylinder, and the oil chamber of the hydraulic cylinder is connected to an accumulator via a throttle valve to provide a buffering effect to the hydraulic cylinder. In the vehicle, the throttle valve is constituted by a variable throttle valve operated in accordance with a vehicle body vibration characteristic signal, and a logic valve is provided in parallel with the variable throttle valve, and the pressure fund of the logic valve and the vehicle body vibration characteristic signal are arranged in parallel with the variable throttle valve. A vehicle suspension control device selectively connected to an accumulator to allow the logic valve to open and to the oil chamber to maintain the logic valve closed via a switching valve operated by the .