JPH05248565A - Fluid pressure control valve - Google Patents

Abstract

PURPOSE:To enable a fluid pressure control valve using a solenoid as an actuator to attain the first objective of improving control pressure resposiveness and convergence quality at the time of changing target control pressure, and the second objective of maintaining both responsiveness and convergence quality compatible with each other at the time of changing the target control pressure, and responding to a demand, if any, for the change of the control pressure responsiveness. CONSTITUTION:A piezoelectric element 12 is so constituted as to radially laid in a spool 6 or a valve port 2, and the sliding motion of the spool 6 is stopped with the elongation of the element 12 via voltage application thereto. This piezoelectric element 12 may also be constituted as to expand and contact depending upon the application or the non-application of voltage and axially laid in the spool 6 or the valve port 2, in series to springs 7 and 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure control valve which is applied to an active hydraulic suspension system or the like and uses a solenoid as an actuator.

[0002]

2. Description of the Related Art Conventionally, as a fluid pressure control valve using a solenoid as an actuator, for example, the actual opening shovel 64-218 is used.
The one described in No. 78 is known.

According to this conventional source, a pilot pressure is generated according to a control command to a solenoid, and when the pilot pressure is higher than the control pressure, the spool moves so as to connect the supply port and the control port, and vice versa. When the pilot pressure is lower than the control pressure, the spool moves so as to connect the return port and the control port, and when the pilot pressure and the control pressure are the same pressure, the spool moves to the position that closes the supply port and the return port. As described above, the spool operates so as to eliminate the pressure difference between the pilot pressure according to the control command and the control pressure being fed back, and the valve for controlling the fluid pressure is shown.

[0004]

However, in the above-mentioned conventional fluid pressure control valve, since the spool is supported by springs at both ends, the supply port and the control port communicate with each other. When fluid force acts on the spool due to the oil flow when the return port and the control port communicate with each other, the spring expands and contracts due to the fluid force, causing the spool to swing, for example, changing the control pressure from a low pressure to a high pressure target value. When starting, the response pressure is inferior and the convergence property is inferior in actually obtaining the control pressure of the target value from the control command.

Further, in the conventional fluid pressure control valve, since the spring constant of the spring supporting the spool is constant, when the spring constant is lowered in order to improve the responsiveness, the convergence is poor. Moreover, when the spring constant is increased to improve the convergence, the response is inferior, and it is not possible to achieve both the response and the convergence. In addition, in a system to which this fluid pressure control valve is applied (for example, an active hydraulic suspension system), it is preferable that the damping force is high under a certain use environment, and the damping force is low under another use environment. If there is a demand to change the damping force obtained by the control pressure, such as that is preferable, it is not possible to meet the demand.

The present invention has been made in view of the above problems, and in a fluid pressure control valve using a solenoid as an actuator, when the target control pressure is changed, the response and convergence of the control pressure are enhanced. Is the first subject.

A second object is to satisfy both the responsiveness and the convergence when changing the target control pressure, and to respond to the change request of the control pressure responsiveness.

[0008]

In order to solve the above-mentioned first problem, in the fluid pressure control valve of the present invention, the piezoelectric element is attached to the spool or the valve hole in the radial direction and is expanded by applying a voltage to the piezoelectric element. The structure is such that the sliding of the spool is stopped.

That is, the supply port formed in the valve hole,
A return port and a control port, a spool movably arranged in the valve hole in the axial direction to switch a supply port and a return port to generate a control pressure to the control port, and springs arranged at both end positions of the spool. A pilot pressure chamber provided on one end side of the spool, a solenoid for producing a pilot pressure according to a control command, a feedback control pressure chamber provided on the other end side of the spool, and attached to the spool or valve hole. The piezoelectric element is arranged in a radial direction to stop the sliding of the spool when the spool is extended by applying a voltage.

In order to solve the above second problem, in the fluid pressure control valve of the present invention, a piezoelectric element that expands and contracts depending on the presence or absence of voltage application is attached to the spool or the valve hole in series with the spring in the axial direction. did.

That is, the supply port formed in the valve hole,
A return port and a control port, a spool movably arranged in the valve hole in the axial direction to switch a supply port and a return port to generate a control pressure to the control port, and springs arranged at both end positions of the spool. A pilot pressure chamber provided on one end side of the spool, a solenoid for producing pilot pressure according to a control command, a feedback control pressure chamber provided on the other end side of the spool, and a spring in the spool or valve hole. Comprises an axially arranged piezoelectric element mounted in series.

[0012]

The operation of the present invention will be described.

For example, when the target control pressure is changed from low pressure to high pressure, a high pressure side target set value slightly higher than the target control pressure and a low pressure side target set value slightly lower than the target control pressure are determined. First, the pilot pressure is increased by a control command to the solenoid. Then, the spool slides against the spring due to the differential pressure between the pilot pressure and the control pressure, and then a voltage is applied to the piezoelectric element at the time when a predetermined time for the communication between the supply port and the control port has elapsed and the spool slides. Motion is stopped. At this point, the control command to the solenoid is stopped.

When the control pressure reaches the target set value on the high pressure side, the voltage to the piezoelectric element is cut off and the force for stopping the spool is released, so that the differential pressure between the control pressure and the pilot pressure resists the spring. Then, the spool slides, and thereafter, when a predetermined time has elapsed for the return port and the control port to communicate with each other, a voltage is applied to the piezoelectric element and the sliding of the spool is stopped. When the control pressure reaches the target set value on the low pressure side, the voltage to the piezoelectric element is cut off, and the restraint on the spool is released, causing the spool to move against the spring due to the differential pressure between the control pressure and pilot pressure. , The spool slides into a position that closes both the return port and the control port. At this point, it is checked whether the control pressure is in the target control pressure range.If it is in the target control pressure range, the control is terminated. If it is outside the target control pressure range, the pressure range is narrowed down and a new one is created. The high pressure side target set value and the low pressure side target set value are determined, and the same control operation as described above is repeated.

Therefore, in both the pressure increasing mode in which the supply port and the control port communicate with each other and the pressure reducing mode in which the return port and the control port communicate with each other, the spool is in the stopped state due to the constraint by the piezoelectric element, and the spring force by the spring is canceled. Therefore, even if the fluid force due to the flow of fluid acts on the spool, the supply port does not close, the hydraulic pressure rises due to the response in a short time from the control command, and the spool is supported by the piezoelectric element to support the spring. There is no associated run-out of the spool, and it is possible to prevent the overshoot and undershoot of the control oil pressure from continuing for a long time, and converge to the control pressure area in a short time.

The operation of the invention according to claim 2 will be described.

For example, when the target control pressure is changed from low pressure to high pressure, the voltage to the piezoelectric element is cut off during the sliding movement of the spool, and the voltage is applied to the piezoelectric element when the supply port and the return port are opened, as in the above. Is applied. This keeps the spring constant low during the sliding movement of the spool, and provides a response that quickly slides according to the force acting on the spool. The constant is kept high, the swinging motion of the spool is suppressed against the fluid force acting on the spool, and high convergence is obtained.

In addition, for example, when applied to an active hydraulic suspension system, it is preferable that the damping force is large with respect to the movement of the vehicle body at the sprung resonance frequency. It is preferable that the damping force is small with respect to the movement of the vehicle body. For such a request,
In the sprung resonance frequency range, voltage is applied to the piezoelectric element,
If the spring constant of the spring that supports the spool is increased, it becomes difficult to connect the supply port and the return port to the control pressure port, and the high pressure of the damper unit is maintained and the damping force increases. In the sprung-unsprung resonance frequency region, if the voltage of the piezoelectric element is cut off and the spring constant of the spring supporting the spool is lowered, it becomes easier to connect the supply port and the return port to the control pressure port, and the damper is connected. It is possible to meet not only the direct control by the damping valve etc. but also the hydraulic pressure control side in response to the change request of the damping force such that the damping force in the unit decreases.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure will be described.

FIG. 1 is a sectional view showing a fluid pressure control valve of a first embodiment corresponding to the present invention described in claim 1 applied to an active hydraulic suspension.

As shown in FIG. 1, the fluid pressure control valve of the first embodiment has a valve hole 2 formed in a valve body 1 in a cylindrical shape.
And a supply port 3 formed in communication with the valve hole 2.
The return port 4 and the control port 5 are arranged in the valve hole 2 so as to be movable in the axial direction, and the supply port 3 and the return port 4 are provided.
To generate a control pressure for the control port 5, a first spring 7 and a second spring 8 arranged at both ends of the spool 6, and a pilot pressure chamber provided at one end of the spool 6. 9, a solenoid 10 for producing a pilot pressure according to a control command, a feedback control pressure chamber 11 provided on the other end side of the spool 6, and a spool 6 attached to the spool 6 and extended by voltage application to slide the spool 6. And a piezoelectric element 12 arranged in a radial direction to stop the movement.

The supply port 3 is connected to a hydraulic pressure source (not shown), the return port 4 is connected to a reserve tank (not shown), and the control port 5 is connected to a control pressure chamber of a damper unit (not shown). ..

Both ends of the spool 6 are supported by both springs 7 and 8 which are preloaded so as to maintain a neutral position with respect to a small external force, and when a fluid force acts in the axial direction of the spool 6, a flow is generated. It slides in the axial direction according to the direction of action of physical strength.

The pilot pressure in the pilot pressure chamber 9 is
It is adjusted by a poppet 13 driven by a solenoid 10. That is, the pilot pressure chamber 9 has an orifice 1
4a communicates with the supply pressure oil passage 14 and also communicates with the drain chamber 17 through a valve seat hole 16 formed in the partition wall 15, so that the poppet 13 arranged at a position facing the valve seat hole 16 can communicate with the drain chamber 17. The hydraulic pressure in the pilot pressure chamber 9 is adjusted according to the forward / backward position. For example, when the poppet 13 moves in the direction to close the valve seat hole 16, the drain amount is suppressed to be small, and the hydraulic pressure in the pilot pressure chamber 9 rises, and when the poppet 13 moves in the direction to open the valve seat hole 16. , The drain amount increases, and the hydraulic pressure in the pilot pressure chamber 9 decreases.

A control pressure oil passage 18 having an orifice 18a formed in the spool 6 is communicated with the feedback control pressure chamber 11 to maintain the control pressure.

The piezoelectric element 12 is constituted by laminating a large number of ceramic piezoelectric element single bodies having electrodes formed on the front and back surfaces and electrically connecting the respective ceramic piezoelectric element single bodies in parallel. A bolt 19 is provided at one end of the valve, and a spool stopper 20 is provided at the other end of the spool stopper 20 in pressure contact with the valve hole 2. The piezoelectric elements 12 arranged in the radial direction mean that the stacking direction of the single ceramic piezoelectric elements is the radial direction.

The element cord 21 connected to the piezoelectric element 12 is embedded in a seal 22 provided in the valve body 1 and is provided in an oil-tight state while keeping the followability to the sliding of the spool 6 to the outside. I try to pull it out.

The element code 21 connected to the piezoelectric element 12 and the solenoid code 23 connected to the solenoid 10 are connected to the output side of the suspension control unit 24. This suspension control unit 2
Reference numeral 4 inputs necessary information from a sensor, a switch or the like, calculates a target control pressure according to the information and predetermined control contents, and outputs a control command to the solenoid 10 and the piezoelectric element 12 to obtain the target control pressure. ..

Next, the operation will be described.

(A) Fluid pressure control processing operation FIG. 2 is a flow chart showing the flow of the fluid pressure control processing operation performed by the suspension control unit 24.
Each step will be described below.

In step 50, when the target control pressure is changed in the main routine in which the target control pressure is calculated depending on the vehicle state, the target control pressure and the valve actuation signal are input to the subroutine side which performs the fluid pressure control process.

In step 51, a high pressure side target set value A slightly higher than the target control pressure and a low pressure side target set value B slightly lower than the target control pressure are determined.

At step 52, an ON command is output to the solenoid 10.

In step 53, it is judged whether or not a predetermined time has elapsed from the solenoid ON command until the supply port 3 and the control port 5 communicate with each other in response to the opening operation response of the spool 6.

In step 54, YES in step 53.
When it is determined that a voltage is applied to the piezoelectric element 12, a command to apply the voltage is output.

At step 55, an OFF command is output to the solenoid 10.

At step 56, it is judged if the control pressure Pc is less than the high pressure side target set value A.

In step 57, when NO is determined in step 56, a command to turn off the voltage application to the piezoelectric element 12 is output.

In step 58, it is judged whether or not a predetermined time has passed from the piezoelectric element OFF command to the communication of the closing operation of the spool 6 until the return port 4 and the control port 5 communicate with each other.

At step 59, YES at step 58.
When it is determined that a voltage is applied to the piezoelectric element 12, a command to apply the voltage is output.

In step 60, it is judged whether the control pressure Pc is less than or equal to the low pressure side target set value B.

At step 61, YES at step 60.
When it is determined that the voltage is applied, a command to turn off the voltage application to the piezoelectric element 12 is output.

At step 62, it is judged if the control pressure Pc is a value within the target value band. If YES, the control is ended, and if NO, at step 63, the high pressure side slightly higher than the target control pressure is reached. The target set value A '(<A) and the slightly lower low pressure side target set value B'(> B) are determined, and step 5 is performed again.
The process from 2 is repeated.

(B) Fluid pressure control action during pressure increase For example, when the target control pressure is changed from low pressure to high pressure, a high pressure side target set value A slightly higher than the target control pressure and a low pressure side target set value B slightly lower than the target control pressure are determined. First, when the pilot pressure is increased by the ON command to the solenoid 6 (step 51) (step 52), the spool 6 is moved to the left side in FIG. 1 against the second spring 8 by the differential pressure between the pilot pressure and the control pressure. Direction, and then a voltage is applied to the piezoelectric element 12 (step 54) when a predetermined time in which the supply port 3 and the control port 5 communicate with each other elapses (step 54), and the spool 6 is locked by the extension of the piezoelectric element 12, The sliding is stopped. At this point, the ON command to the solenoid 6 is stopped (step 55).

The control pressure Pc is the high pressure side target set value A.
When the voltage reaches the first pressure, the voltage to the piezoelectric element 12 is cut off (step 57), and the force for stopping the spool 6 is released, so that the first spring 7 becomes a pressure difference between the control pressure and the pilot pressure.
The spool 6 slides against the force, and after that, when a predetermined time in which the return port 4 and the control port 5 communicate with each other elapses, a voltage is applied to the piezoelectric element 12 and the sliding of the spool 6 is stopped (step 59). ). Then, when the control pressure Pc reaches the low pressure side target set value B, the voltage to the piezoelectric element 12 is cut off (step 61), and the restraint of the spool 6 is released, so that the differential pressure between the control pressure and the pilot pressure is generated. The spool 6 starts to move against the spring 8, and the spool 6 slides to a position where both the return port 4 and the control port 5 are closed. At this point, it is checked whether or not the control pressure is within the target value band (step 62). If it is in the target value band, the control is terminated, and if it is outside the target value band, the pressure range is narrowed down further. The high pressure side target set value A'and the low pressure side target set value B'are newly determined (step 63), and the control operation similar to the above is repeated.

That is, looking at the target set value characteristic of the control pressure, the conventional example changes the target set value stepwise as shown by the solid line characteristic of FIG. As indicated by the dotted line characteristic of, the high pressure side target set value A is first set from the current control pressure, then the low pressure side target set value B is set, and further, the high pressure side target set value A ′ and the low pressure side are set. The target set value itself, such as the target set value B ′, is given with a gradual convergence characteristic.

Therefore, regarding the responsiveness, the supply port 3
Return port 4 even in boost mode where control port 5 communicates with
Even in the decompression mode in which the control port 5 and the control port 5 communicate with each other, the spool 6 is in a stopped state due to the constraint by the piezoelectric element 12 and the spring force of the springs 7 and 8 is canceled, so that the fluid force due to the fluid flow is applied to the spool 6. Supply port 3 even if it works
Does not close, and the hydraulic pressure rises in response to the control command in a short time.

Regarding the convergence, there is no swaying motion of the spool 6 due to the support of the spring due to the constraint of the spool 6 by the piezoelectric element 12, and as shown by the dotted line characteristic in FIG.
High pressure side target set values A, A'set higher than the target pressure
And low pressure side target set value B, which is set lower than the target pressure,
As shown in the conventional example shown by the solid line characteristic in FIG. 4, the convergence characteristic along B ′ is exhibited, and overshoot or undershoot of the control oil pressure for a long time is suppressed by the runout movement of the spool, and the target control pressure is set in a short time. Converge.

(C) Fluid pressure control action during depressurization In the fluid pressure control action during depressurization, the low pressure side target set value is first set from the current control pressure to perform the pressure reduction control, and then the high pressure side target setting. With regard to responsiveness and convergence, it is possible to obtain high responsiveness and high convergence like the fluid pressure control action at the time of pressure increase, simply by setting the value and performing pressure increase control. Become.

As described above, in the first embodiment, in the fluid pressure control valve using the solenoid 10 as the actuator, the piezoelectric element 1 is arranged on the spool 6 in the radial direction.
Since the structure in which the spool 2 is attached and the sliding of the spool 6 is stopped by the extension due to the voltage application to the piezoelectric element 12, the responsiveness and convergence of the control pressure can be improved when the target control pressure is changed.

In the first embodiment, the piezoelectric element 12 is attached to the spool 6 in a radial arrangement.
At the position of the valve hole 2 facing the spool 6, the valve body 1
The piezoelectric elements 12 may be provided in a radial arrangement while being embedded in the.

(Second Embodiment) First, the structure will be described.

FIG. 5 is a sectional view showing a fluid pressure control valve of a second embodiment corresponding to the present invention described in claim 2 applied to an active hydraulic suspension.

In the fluid pressure control valve of the second embodiment, as shown in FIG. 5, the arrangement of piezoelectric elements is different from that of the first embodiment. That is, in the second embodiment, the piezoelectric element 12 is axially arranged in series with the spring 7 and is attached to the spool 6 by adhering it with the epoxy resin 25 or the like.

Since the other structures are similar to those of the fluid pressure control valve of the first embodiment shown in FIG. 1, the corresponding structures are designated by the same reference numerals and the description thereof will be omitted.

Next, the operation will be described.

(A) Piezoelectric element control operation FIG. 6 is a flowchart showing the flow of the piezoelectric element control operation performed by the suspension control unit 24. Each step will be described below.

In step 64, the vibration level of the vehicle body is detected by the sensor signal from the G sensor or the like.

In step 65, a low-pass filter and a high-pass filter are applied to the vibration level of the vehicle body to determine whether or not the sprung resonance frequency range (around 1 Hz).

If YES at step 65,
Proceeding to step 66, the voltage to the piezoelectric element 12 is turned on.

In step 67, similarly to step 65, it is determined whether the vibration level of the vehicle body is in the sprung resonance frequency range (around 1 Hz).

If YES at step 67,
Returning to step 66, the voltage ON to the piezoelectric element 12 is maintained, and when NO is determined in step 67, the process proceeds to step 68, and the voltage to the piezoelectric element 12 is turned OFF.

(B) Suspension damping action When applied to an active hydraulic suspension system, as shown in FIG. 7, the damping force is large with respect to the movement of the vehicle body (fluffy vibration) at the sprung resonance frequency. It is preferable that the damping force be small with respect to the movement of the vehicle body (rough vibration) at the sprung-to-unsprung resonance frequency.

In response to such a demand, in the active hydraulic suspension system, since the damping force cannot be changed by the fluid pressure control valve, as shown by the dotted line characteristic in FIG.
While the reduction of the vehicle body vibration level in the sprung resonance frequency region is not sufficient, in the second embodiment, if it is in the sprung resonance frequency region, step 64 → step 65 in FIG.
→ Proceeding to step 66, by applying a voltage to the piezoelectric element 12, the springs 7 and 8 supporting the spool 6 are preloaded by the extension of the piezoelectric element 12 and the spring constants of the springs 7 and 8 are increased. .. As a result, it becomes difficult for the supply port 3 and the return port 4 to communicate with the control pressure port 5, and the high pressure of the damper unit is maintained and the damping force increases. That is, the hatched portion in FIG. 7 greatly reduces the vehicle body vibration level.

In the sprung-to-unsprung resonance frequency region, the process proceeds from step 67 to step 68 in FIG. 6, the voltage of the piezoelectric element 12 is cut off, the piezoelectric element 12 is shortened, and the spring 7, which supports the spool 6, The spring constant of No. 8 will be lowered. As a result, the supply port 3 and the return port 4 are easily communicated with the control pressure port 5, the damping force in the damper unit is reduced, and the damping force characteristic in the fluid pressure control valve is as shown in FIG. Therefore, although it is effective in the sprung resonance frequency region, the sprung to unsprung resonance frequency region exhibits a vehicle body vibration level similar to that of the conventional active hydraulic suspension system. The damping is mainly operated by a damping valve provided in the damper unit.

As described above, the request for changing the damping force can be met not only by the direct control by the damping valve but also by the hydraulic pressure control side.

(C) When using a piezoelectric element for hydraulic control For example, when the target control pressure is changed from a low pressure to a high pressure, the piezoelectric element 12 is moved during the sliding operation of the spool 6 as in the first embodiment.
To the piezoelectric element 12 when the supply port 3 and the return port 4 are opened.

As a result, during the sliding operation of the spool 6, the spring constant is kept low, and the response to quickly slide according to the force acting on the spool 6 is obtained, and the supply port 3 and the return port 4 are set. When the pressure is increased and the pressure is reduced when the spring is opened, the spring constant is kept high, and the oscillating movement of the spool 6 is suppressed to be small with respect to the fluid force acting on the spool 6, and high convergence is obtained.

As described above, in the second embodiment, in the fluid pressure control valve using the solenoid 10 as an actuator, the piezoelectric element 12 that expands and contracts depending on the presence / absence of voltage application.
Is configured so that it is attached to the spool 6 in series with the springs 7 and 8 in the axial direction. Therefore, when changing the target control pressure,
Both responsiveness and convergence can be achieved, and when there is a request for changing the control pressure responsiveness, the change request can be met.

Further, the fluid pressure control valve is applied to the active hydraulic suspension system so that the voltage is applied to the piezoelectric element 12 in the sprung resonance frequency range and the voltage to the piezoelectric element 12 is cut in the other resonance frequency range. Therefore, compared to the case where only the damping force control by the damping valve or the like is performed, it is possible to further improve the maneuverability and the riding comfort in a higher dimension.

In the second embodiment, one piezoelectric element 12 is provided, and the neutral position of the spool 6 is displaced when the piezoelectric element 12 is extended. It is half the amount of elongation, and since it is extremely small, it has almost no effect on hydraulic control.

(Third Embodiment) FIG. 9 is a sectional view showing a fluid pressure control valve of a third embodiment corresponding to the present invention according to claim 2 applied to an active hydraulic suspension.

The fluid pressure control valve of the third embodiment is an example in which two piezoelectric elements 12 are provided on both sides of the spool 6.

Therefore, in this third embodiment, in addition to the effect of the fluid pressure control valve of the second embodiment, two piezoelectric elements 12, 1 are used.
By simultaneously extending and shortening 2, the effect that the neutral position of the spool 6 can always be ensured is obtained.

In the second and third embodiments described above,
Although an example in which the piezoelectric element arranged axially is provided on the spool side is shown, the piezoelectric element may be provided on the valve hole side that receives the spring. In this case, wiring that follows the movement of the spool is not required, and it is simple. Simple wiring structure.

(Fourth Embodiment) FIG. 10 is a sectional view showing a fluid pressure control valve of a fourth embodiment corresponding to the present invention according to claim 2 applied to an active hydraulic suspension.

The fluid pressure control valve of the fourth embodiment is an example in which one piezoelectric element 12 is provided at an intermediate position of the spool 6.

Therefore, in this fourth embodiment, in addition to the effect of the fluid pressure control valve of the third embodiment, it is possible to always secure the neutral position of the spool 6 while being cost-effective with only one piezoelectric element 12. The effect is obtained.

Although the embodiments have been described with reference to the drawings, the fluid pressure control valve of the present invention is not limited to the application to the active hydraulic suspension system, and the responsiveness and the convergence are required. Can be applied to other hydraulic control systems.

[0081]

According to the present invention of claim 1, in a fluid pressure control valve using a solenoid as an actuator,
Piezoelectric elements are installed in the spool or valve hole in the radial direction, and the sliding of the spool is stopped by extension due to voltage application to the piezoelectric element, so when the target control pressure is changed, the response and convergence of the control pressure The effect that it can raise is obtained.

According to the second aspect of the present invention, in a fluid pressure control valve using a solenoid as an actuator, a piezoelectric element that expands and contracts depending on whether or not a voltage is applied is axially arranged in a spool or valve hole in series with a spring. Since it is configured to be attached with, it is possible to achieve both responsiveness and convergence when changing the target control pressure, and it is possible to respond to the change request when there is a change request for the control pressure responsiveness. Is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a fluid pressure control valve according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a fluid pressure control operation performed by a suspension control unit of the first embodiment control valve.

FIG. 3 is a characteristic diagram of a target set value when the target control pressure is increased.

FIG. 4 is a characteristic diagram of an actual control pressure change characteristic when the target control pressure is increased.

FIG. 5 is a sectional view showing a fluid pressure control valve according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a flow of a piezoelectric element control operation performed by a suspension control unit of the second embodiment control valve.

FIG. 7 is a vehicle body vibration level characteristic diagram of a vehicle equipped with an active hydraulic suspension system to which the control valve of the second embodiment is applied.

FIG. 8 is a damping force characteristic diagram of the active hydraulic suspension system to which the control valve of the second embodiment is applied.

FIG. 9 is a sectional view showing a fluid pressure control valve according to a third embodiment of the present invention.

FIG. 10 is a sectional view showing a fluid pressure control valve according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Valve body 2 Valve hole 3 Supply port 4 Return port 5 Control port 6 Spool 7 1st spring 8 2nd spring 9 Pilot pressure chamber 10 Solenoid 11 Feedback control pressure chamber 12 Piezoelectric element

Claims (2)

[Claims] 1. A supply port, a return port, and a control port formed in a valve hole, and a spool disposed in the valve hole so as to be movable in the axial direction, and switching the supply port and the return port to generate a control pressure to the control port. A spring arranged at both ends of the spool; a pilot pressure chamber provided at one end of the spool; a solenoid for producing pilot pressure according to a control command; and a solenoid provided at the other end of the spool. A fluid pressure control valve, comprising: a feedback control pressure chamber; and a piezoelectric element that is attached to the spool or the valve hole and is arranged in a radial direction to stop the sliding of the spool when the spool is extended by applying a voltage. 2. A supply port, a return port, and a control port formed in the valve hole, and a spool disposed in the valve hole so as to be movable in the axial direction, and switching the supply port and the return port to generate a control pressure to the control port. A spring arranged at both ends of the spool, a pilot pressure chamber provided at one end of the spool, a solenoid for producing pilot pressure according to a control command, and a solenoid provided at the other end of the spool. A fluid pressure control valve comprising: a feedback control pressure chamber; and an axially arranged piezoelectric element in which a spring is mounted in series with the spool or the valve hole.