JPH0629046Y2 - Pilot check valve for hydraulic suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a pilot check valve most suitable for use in a hydraulic suspension used for vehicle attitude control and the like.

(Prior Art) Conventionally, as a hydraulic suspension for controlling a vehicle height and a vehicle attitude, for example, a device described in JP-A-62-96115 is known.

In this conventional device, an actuator for adjusting the vehicle height is provided between the vehicle body and the axle, and the hydraulic pressure output from the pressure control valve allows the actuator to extend and retract to control the vehicle height and the vehicle attitude. It was.

(Problems to be solved by the invention) However, in such a conventional device, the drain circuit has no pilot check valve for leak prevention, so the engine is stopped and the hydraulic pressure supply is stopped. If so, the hydraulic pressure in the actuator and the accumulator is drained, and the vehicle height decreases to the minimum vehicle height. Moreover, when the engine is started, conversely, the vehicle height decreases from the lowered vehicle height to a predetermined value. Rise to height,
There was a problem that the driver felt uncomfortable.

Furthermore, in order to solve this problem, it is possible to install a pilot check valve in the middle of the drain circuit, but normally the operating pressure of the pilot check valve is
When applied to the spool of the check valve, there are variations in the valve opening pressure when the pressure rises and the valve closing pressure when the pressure falls, which causes a problem that the vehicle height when the vehicle is stopped is not constant.

In view of such a problem, the present invention provides a check valve that has no variation in the opening pressure when the pressure increases and the closing pressure when the pressure decreases, and further provides a check feeling. When installed in the drain circuit of the hydraulic suspension as described above, it is necessary to prevent the vehicle height from dropping or rising to the minimum vehicle height when the vehicle height / vehicle attitude control is stopped or started. To aim.

(Means for Solving Problems) In order to achieve the above-mentioned object, the present invention has a pressure receiving portion and opens when the hydraulic pressure introduced into the pressure receiving portion is equal to or higher than a predetermined value and closes when the hydraulic pressure is equal to or lower than a predetermined value. A valve portion, a pilot port communicated with the pressure receiving portion, a line pressure port connected to a line, and a drain port connected to a drain circuit are formed,
A line pressure and a pilot port are connected when the line pressure is equal to or higher than a predetermined value, and a hydraulic pressure detection unit that operates to connect the pilot port to the drain port when the line pressure is equal to or lower than the predetermined value is provided.

(Operation) In the suspension pilot check valve of the present invention configured as described above, when the line pressure is equal to or higher than the predetermined value, the line pressure port where the line pressure is introduced and the pressure receiving portion of the valve portion are detected in the hydraulic pressure detection portion. It is connected to the pilot port that is in communication with it, whereby the line pressure is introduced into the pressure receiving portion and the valve portion is opened.

On the other hand, when the line pressure is equal to or lower than the predetermined value, the pilot port and the drain port are communicated with each other, the hydraulic pressure is not introduced to the pressure receiving portion, and the valve portion closes.

As described above, in the present invention, the valve portion is not turned on or off according to the hydraulic pressure, but is turned on or off by the operation of the hydraulic pressure detection portion according to the line pressure.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, the configuration will be described.

FIG. 1 is a hydraulic suspension B to which a pilot check valve 9 for hydraulic suspension according to an embodiment of the present invention is applied.
FIG. 1 is an overall view showing a vehicle height adjustment actuator 1 provided between the vehicle body and the axle. The actuator 1 has a cylinder tube 1a, a piston 1b, and a piston rod 1c, and is formed so as to be capable of supplying a hydraulic pressure from a pressure control valve 2 to an internal fluid chamber of the cylinder tube 1a via an output circuit 3. The vehicle height can be adjusted by expanding and contracting based on the difference in pressure receiving area between the upper and lower sides. The actuator 1 is provided at the position of each wheel of the vehicle, and the attitude of the vehicle can be controlled by adjusting the vehicle height at each position. Further, the output circuit 3 is provided with an accumulator or the like that forms a gas spring.

The pressure control valve 2 has a hydraulic pressure supply circuit 5 that is hydraulically supplied from a pump P based on a control signal ic from the control circuit 4.
A well-known structure for controlling the output hydraulic pressure by selectively connecting the output circuit 3 and the drain circuit 6 reaching the tank T is used. The pump P is driven by the rotation of the engine E.

The control circuit 4 is connected to an input sensor group 4a and an ignition switch 4b which are composed of a G sensor, a vehicle speed sensor, a vehicle height sensor, and the like for detecting accelerations occurring in the front, rear, left, right, and up and down directions of the vehicle body. , Calculates the hydraulic pressure required to set the vehicle posture to a target posture such as horizontal, based on the input signal from the input sensor group 4a, and outputs the control signal ic to the pressure control valve 2 based on the calculation result. To do. Further, the control circuit 4 receives the ON signal of the ignition switch 4b and starts the above-mentioned control operation,
This control operation is stopped by the F signal.

The hydraulic pressure supply circuit 5 is provided with a relieve valve 7 on the upstream side and a check valve 8 on the downstream side. Further, the drain circuit 6 is provided with a pilot check valve 9 according to the embodiment of the present invention. An accumulator (not shown) for accumulating pressure is provided in the middle of the hydraulic pressure supply circuit 5 so that the hydraulic pressure is stably supplied.

The check valve 8 is a valve for preventing backflow, which has a normal structure and is opened when the supply liquid pressure exceeds a predetermined value.

The relief valve 7 is a body 1 as shown in FIG.
A valve hole 10a for a relief valve is formed in the upper part of the body 10 in a part of the body 0. Also,
A drain hole 10b communicating with the drain circuit 6 is formed perpendicularly to the intermediate portion of the valve hole 10a.

A valve seat 7a is slidably provided in the valve hole 10a, and a check ball 7c is biased in the valve seat 7a by a spring 7b in a valve closing direction.
Is provided. The valve seat 7a is biased by a spring 7e in the direction in which the drain port 7d formed in the valve seat 7a is opened in the drain hole 10b.

Then, the hydraulic pressure on the upstream side of the hydraulic pressure supply circuit 5 is introduced into one end side of the valve seat 7a into the valve hole 10a, while the other end side of the hydraulic pressure supply circuit 5 downstream thereof is introduced. Hydraulic pressure is introduced through the orifice 7f.

As shown in FIG. 1, the pilot check valve 9 is composed of a hydraulic pressure detection section 91 and a valve section 92.

The hydraulic pressure detection portion 91 is composed of a sub piston portion 91a, a check ball portion 91b, and a main piston portion 91c. That is, as shown in FIG. 3 which is a sectional view taken along the line III-III in FIG. 2, the hydraulic pressure supply circuit 5 is connected between the body 10 and the sub spring 91d provided at the upper end of the body 10 in contact with the upper spring. Back chamber 91e and line pressure port 9
1f and a sub-valve seat 91h having a hole 91g communicating with the line pressure port 91f, and a sub-piston 91j slidable in the sub-valve seat 91h and in contact with the lower end of the sub-spring 91d.
And form a sub-piston portion 91a.
The body 10 has a hydraulic pressure supply circuit 5 and the back chamber 91e.
And a communication hole 91q that communicates with the line pressure port 91f.

The check ball portion 91b includes a collar 91k contacting a lower portion of the sub valve seat 91h and a collar 91k.
a check ball 91m capable of slightly shifting the inside of k, a pilot port 91n is formed on the outer peripheral portion of the collar 91k, and a communication hole 9 for communicating the pilot port 91n with the inside of the collar 91k.
1p is formed.

The main piston portion 91c presses the collar 91k against the sub-valve seat 91h, has a communication hole 91s that communicates with the drain port 91r of the body 10, and a main seat valve 91t, and this main seat valve 91t.
a main piston 91v that is slidable inside t, a main spring 91w that presses the main piston 91v toward the check ball 91m, and a main spring 91v.
A stopper plate 91x for fixing the lower end of w, an adjusting bolt 91y for adjusting the fixing position of the stopper plate 91x, and a connector 91z for covering these
It is composed by.

Further, the sub piston portion 91a and the check ball portion 91
An O-ring 911 that seals the b, an O-ring 912 that seals the check ball portion 91b and the main piston portion 91c, and an O-ring 913 that seals the main piston portion 91c and the atmosphere side are provided.

Note that FIG. 3 shows a state in which the right half and the left half of the axis line are different, and in the right half, the check ball 91m is shifted to a position connecting the pilot port 91n and the drain port 91r. The left half shows a state in which the check ball 91m is shifted to a position connecting the pilot port 91n and the line pressure port 91f.

As shown in FIG. 2, the valve portion 92 is provided in the middle of the drain hole 10b of the body 10, and has a plug 92a to which the upstream side 6a of the drain circuit 6 is connected,
The check ball 9 is movably supported in the axial direction with respect to the plug 92a and is urged by a spring 92b.
2c and a ball retainer 92d, and the plug 92a are arranged and fixed in the middle of the drain hole 10b and are opened on the upstream side 6a of the drain circuit 6, and
This opening end has a seat hole 92e which is opened and closed by the check ball 92c, and further, the drain hole 10 is provided.
a collar 92g having a communication hole 92f communicated with b,
It is slidably provided on the opposite side of the plug 92a with the drain hole 10b interposed therebetween, and the tip end thereof can come into contact with the check ball 92c, and the base end side thereof is communicated with the pilot port 91n via a communication passage 92h. The drain piston 92m is provided with a pressure receiving surface (pressure receiving portion) 92k facing the back chamber 92j. In addition, in the valve portion 92 shown in FIG. Shows different states. The upper half shows a closed state in which the check ball 92c closes the seat hole 92e, and the lower half shows the check ball 92c in the seat hole 92e.
The valve opening state in which e is opened is shown.

Next, the operation of this embodiment will be described.

(A) During vehicle attitude control When the ignition switch 4b is turned on and the engine E is driven, hydraulic pressure is supplied from the pump P to the hydraulic pressure supply circuit 5, and the control circuit 4 outputs a signal from the input sensor 4a. Based on this, the control signal ic is output.

In this case, in the pilot check valve 9 of the embodiment,
As shown in the left half of the axis of FIG. 3, the hydraulic pressure of the hydraulic pressure supply circuit 5 is introduced into the back chamber 91e through the communication hole 91q, and when this hydraulic pressure exceeds a predetermined value, the sub-piston 91j is stroked. As a result, the check ball 91m is shifted, and the line pressure port 91f has a hole 91g and a communication hole 91.
It is connected to the pilot port 91n via p.

Therefore, in the valve portion 92, as shown in the lower half of the axis of FIG.
That is, a fluid pressure higher than a predetermined level of the fluid pressure supply circuit 5 is introduced, the fluid pressure is received by the pressure receiving surface 92k of the drain piston 92m, the drain piston 92m makes a stroke, and the check ball 92c is pushed to open the valve. It

Therefore, the drain circuit 6 is in a flowable state and drained from the pressure control valve 2 to the tank T.

Further, by operating the pressure control valve 2 based on the control signal ic, the vehicle height is increased when the output hydraulic pressure of the output circuit 3 is increased, and the vehicle height is also decreased when the output hydraulic pressure is decreased.

(B) When the ignition switch is off When the ignition switch 4b is turned off, the drive of the engine E is stopped and the pump P is stopped, and the operation of the control circuit 4 is stopped and the output of the control signal ic is stopped.

In this case, in the pilot check valve 9 of the embodiment,
The hydraulic pressure of the back chamber 91e into which the hydraulic pressure of the hydraulic pressure supply circuit 5 is introduced is reduced, the sub-piston 91j makes a stroke as shown in the right half of the axis line, the check ball 91m is shifted, and the pilot port 91n is drained. It is connected to the circuit 6.

Therefore, the back chamber 92j of the valve portion 92 becomes the atmospheric pressure, the hydraulic pressure received by the pressure receiving surface 92k of the drain piston 92m disappears, and the drain piston 92m moves to the spring 92.
It is pushed back to b and closed.

Therefore, the drain circuit 6 is cut off.

In this way, the valve portion 9 of the pilot check valve 9
Since the drain circuit 6 is cut off by 2 and the hydraulic pressure supply circuit 5 is also cut off by the check valve 8, the ignition switch 4b is turned off for the actuator 1.
The hydraulic pressure at that time is contained, so that the vehicle attitude and the vehicle height when the ignition switch 4b is OFF are maintained.

In this way, when the control is stopped, the vehicle posture change and the vehicle height decrease do not occur.
When the control is started by turning b on, the vehicle height is not increased.

As described above, in the pilot check valve 9 of the embodiment, the valve portion 92 that opens and closes the drain circuit 6 is
It does not stroke quantitatively according to the hydraulic pressure of the hydraulic pressure supply circuit 5, but operates ON / OFF when it is above or below a predetermined hydraulic pressure, so there is no variation in the operation and it operates with a sense of moderation. It has the characteristics of

Further, the hydraulic suspension unit of the embodiment to which this pilot check valve is applied has the characteristic that the vehicle attitude and vehicle height do not change when the control is stopped or started.

Although the embodiment has been described above with reference to the drawings, the specific configuration is not limited to this embodiment, and even if there are design changes and the like within the scope of the invention, the invention is included.

For example, in the embodiments, the pump driven by the engine rotation is shown, but it may be driven by an electric motor.

Further, in the embodiment, the control operation of the control circuit is stopped by turning off the ignition switch, but after the ignition switch is turned off for a predetermined time or a predetermined time in the accumulator downstream of the check valve of the hydraulic pressure supply circuit. The control operation may be continued while the hydraulic pressure is stored.

(Effect of the Invention) As described above, in the present invention, since the valve section is operated ON / OFF by the operation of the hydraulic pressure detection section according to the line pressure, there is no variation in the operation and a moderation feeling. In addition, when this check valve is applied to the drain circuit of the hydraulic suspension, there is an effect that the vehicle height when the control is stopped is unlikely to vary and the vehicle height is unlikely to change. It is a thing.

[Brief description of drawings]

FIG. 1 is an overall view showing a hydraulic suspension to which a pilot check valve for a hydraulic suspension according to an embodiment of the present invention is applied, FIG. 2 is a sectional view showing a main part of the pilot check valve of the embodiment, and FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2 showing a main part of the pilot check valve of the embodiment. 5 ... Fluid pressure supply circuit (line) 6 ... Drain circuit 9 ... Pilot check valve 91 ... Fluid pressure detection section 92 ... Valve section 91f ... Line pressure port 91n ... Pilot port 91r ... Drain port 92k ... Pressure receiving section (pressure receiving surface)

Claims (1)

[Scope of utility model registration request] 1. A valve portion having a pressure receiving portion, which opens when the hydraulic pressure introduced into the pressure receiving portion is greater than or equal to a predetermined value and closes when the hydraulic pressure is less than or equal to a predetermined value, and a pilot port and a line connected to the pressure receiving portion. A line pressure port connected to the line and a drain port connected to the drain circuit are formed.If the line pressure is above a predetermined level, the line port and pilot port are connected, and if the line pressure is below a predetermined level, the pilot port is connected to the drain port. A pilot check valve for a hydraulic suspension, comprising: a hydraulic pressure detection unit that operates so as to be connected to.