JPH067364Y2 - Pressure control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a pressure control valve for controlling a line pressure from a fluid supply source to obtain a control pressure, and is applied to, for example, an active suspension of a vehicle. Is suitable.

[Conventional technology]

As a conventional pressure control valve for a vehicle, for example, the actual opening number 59
Some are described in Japanese Patent Publication No. -150046.

In this conventional example, the pressure supplied to the lockup chamber is regulated by a pressure control unit using a pressure reducing valve to control the engagement force of the lockup clutch, and the line pressure is controlled by a proportional solenoid and a fixed orifice. A pilot pressure is generated, and this is supplied to one end of the spool of the pressure reducing valve, and the converter pressure as a hydraulic pressure source is supplied to the other end of the spool, and the converter pressure and pilot pressure are balanced. The spool moves so that the converter pressure is reduced in response to this and supplied as lockup pressure to the lockup chamber.

[Problems to be solved by the invention]

However, in the above-mentioned conventional pressure control valve, since the pilot pressure is generated by using the pilot pressure generation mechanism by the fixed orifice and the thrust of the proportional solenoid, the line pressure is always consumed by the pilot pressure generation mechanism. Moreover, since its flow rate cannot be narrowed down much in relation to the responsiveness of the spool, if it is applied to an active suspension of a vehicle, the operating rate of the hydraulic pump will increase and the load on the engine will also increase. There are problems that the fuel efficiency is lowered and it is not practical, and that the fixed orifice is used in the pilot system, so that the responsiveness is greatly changed due to the change in viscosity due to the change in oil temperature.

In view of this, the present invention configures the pressure reducing valve that forms the pilot pressure so that the fluid is not consumed in the closed state when the spool does not need to be moved without using the fixed throttle. It is an object of the present invention to provide a pressure control valve that can solve the problems.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention has a main spool 6 movable in a main valve housing 2 and an input port 2.
A feedback chamber 6h in which the control pressure P _C is fed back as an urging force for urging the main spool 6 in the direction of closing c is supplied, and a pilot pressure P _PP for urging the main spool 6 so as to oppose the urging force is supplied. And a pilot pressure chamber 6g for controlling the control pressure P _C and the pilot pressure P
_The input port 2c and the input / output port 2d or the input / output port 2d and the drain port 2e are made to communicate with each other according to the moving position of the main spool 6 which is determined based on the pressure difference with _PP, and based on the pilot pressure P _PP . In the pressure control valve that outputs the control pressure P _C from the input / output port 2d, the control pressure is input as the primary pressure, and the input control pressure is reduced using the pilot spool 7 to form the pilot pressure. A valve 5 is provided, and the pressure reducing valve 5 causes the thrust of the proportional solenoid 8 to act on the pilot spool 7 in a direction to increase the pilot pressure and feeds back the pilot pressure to reduce the pilot pressure. To generate a pressure proportional to the thrust of the proportional solenoid 8.

[Action]

In this invention, the pressure control valve supplies the control pressure to the feedback chamber of the three-way spool valve, and also supplies the pilot pressure to the pipe pressure chamber formed on the opposite side of the feedback chamber with the spool interposed therebetween. The control pressure is generated according to the pilot pressure, and the pressure reducing valve feeds back the pilot pressure in the pilot pressure reducing direction to act on the pilot spool, and the proportional solenoid thrust force is applied to the pilot spool in the pilot pressure increasing direction. Generates pilot pressure proportional to the thrust of the proportional solenoid. Therefore, when the control pressure does not fluctuate, the pilot pressure is not regulated, the input flow rate is cut off, and the energy consumption is reduced.

〔Example〕

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

FIG. 1 is a sectional view showing an embodiment of the present invention.

In the figure, reference numeral 1 is a pressure control valve, which has a relatively large insertion hole 2
a and a main valve housing 2 of a bottomed cylindrical shape in which a through hole 2a that is continuous with the lower end thereof and is slightly smaller in diameter than the through hole 2a are formed coaxially, and an through hole 2a that closes the upper end of the main valve housing 2 is coaxial. And a pressure reducing valve housing 3 having an insertion hole 3a that is communicated with each other and has a diameter considerably smaller than that of the pressure reducing valve housing 3. A main pressure control unit 4 is provided in the main valve housing 2 and a main pressure control unit 4 is provided in the pressure reducing valve housing 3. A pressure reducing valve portion 5 is formed as a pressure reducing valve for supplying a pilot pressure to each.

The main pressure control unit 4 includes the insertion holes 2 a, 2 of the main valve housing 2.
The main spool 6 is provided in the b so as to be slidable in the axial direction. And the insertion hole 2a of the main valve housing 2
An input port 2c, an input / output port 2d, and a drain port 2e are formed in that order from the lower side on the inner peripheral surface corresponding to.

On the other hand, the main spool 6 has a land 6a facing the input port 2c and a land 6 facing the drain port 2e.
b is formed, and both lands 6a, 6 are provided at the lower end.
The land 6c inserted into the insertion hole 2b having a diameter smaller than b is formed, and the annular groove portion 6 between the lands 6a and 6b is formed inside.
A communication hole 6f is provided that connects d with the step 6e between the land 6a and the land 6c. A pilot pressure chamber 6g is provided between the upper end of the insertion hole 2a of the valve housing 2 and the upper end of the land 6b of the spool 6, and the pilot pressure chamber 6g is formed between the lower end of the insertion hole 2a of the valve housing 2 and the lands 6a and 6c of the spool 6. In the meantime, the feedback chamber 6h becomes the land 6 of the spool 6.
A damper chamber 6i is formed between the lower end of c and the bottom of the insertion hole 2b, and the damper chamber 6i is connected to an oil tank 18 of a hydraulic source, which will be described later, via a fixed throttle 6k.

Further, the spool 6 is biased downward by an offset spring 6l inserted between the upper end surface of the land 6b and the upper end surface of the insertion hole 2a of the valve housing 2.

The pressure reducing valve unit 5 includes a spool 7 (pilot spool) axially slidably disposed in the insertion hole 3a of the pressure reducing valve housing 3, and an actuator 8a integrally connected to the spool 7.
And a proportional solenoid 8 having an exciting coil 8b.

An input port 3b and a drain port 3c are formed on the inner peripheral surface of the valve housing 3 with a predetermined space therebetween, and the input port 3b is an input / output of the main pressure control unit 4 via a hydraulic pipe or an internal communication passage 3d. It communicates with the port 2d.

The spool 7 has lands 7a and 7b that face the input ports 3b and 3c, and a communication passage 7d that connects the annular groove 7c between the lands 7a and 7b and the lower end surface of the spool 7 is formed inside.

A fixed throttle 10 is provided between the insertion hole 2a of the main valve housing 2 and the insertion hole 3a of the pressure reducing valve housing 3, and a feedback chamber 7f is formed between the fixed throttle 10 and the lower end surface of the spool 7. The offset spring 9 is inserted in the feedback chamber 7f, and the spool 7 is biased upward by the offset spring 9.

The input port 2c of the valve housing 2 is connected to the hydraulic power source 13 via the hydraulic pipe 12, and the input / output port 2d
Is connected to the pressure chamber of the hydraulic cylinder of the active suspension 15 to be controlled via the hydraulic pipe 14.

The hydraulic pressure source 13 includes a hydraulic pump 17 connected to the output shaft of an engine (not shown) connected to the hydraulic pipe 12 via a check valve 16 and an unload valve connected between the hydraulic pipe 12 and the tank 18. 19 and an accumulator 20 and a pressure switch 21 connected to the downstream side of the unload valve 19 of the hydraulic pipe 12, and outputs a predetermined line pressure P _L set by the unload valve 19.

The active suspension 15 has a hydraulic cylinder 21 interposed between the unsprung part and the sprung part of the vehicle, and the upper end of the cylinder tube 21a is rotatably attached to the vehicle body side member 22. , Piston rod 21b
Is attached to the wheel side member 23, and a coil spring 24 that supports a static load of the vehicle body is interposed between the vehicle body side member 22 and the wheel side member 23.

The pressure chamber 21d defined by the piston 21c fixed to the upper end of the piston rod 21b of the hydraulic cylinder 21 is connected to the input / output port 2d of the pressure control valve 1 via the hydraulic pipe 14 and has a fixed throttle. It communicates with the accumulator 26 via 25. Here, the fixed throttle 25 absorbs only vibration input of a relatively high frequency (7 to 8 Hz or higher) corresponding to the unsprung resonance frequency range of the vehicle transmitted to the pressure chamber 21d of the hydraulic cylinder 21. Acts like.

On the other hand, the vehicle body-side member 22 is provided with a vertical acceleration detector 27 for detecting a posture change state of the vehicle body. From the vertical acceleration detector 27, a posture change of the vehicle body, that is, a posture change made by a voltage signal according to the vertical acceleration. A detection signal is output, and this is supplied to the control device 28.

The control device 28 uses the pressure control valve 1 to set a predetermined offset pressure P.
An offset pressure setting circuit 29 for outputting an offset pressure command value V ₁ for outputting _O , and the vertical acceleration detector 2
An integrating circuit 30 to which the vertical acceleration detection signal of 7 is supplied;
And an adder 31 for adding the outputs of both circuits 29, 30. Here, the integration circuit 30 includes the vertical acceleration detector 2
The vertical acceleration detection signal ‖ of 7 is integrated to calculate a vertical speed calculation value Kn‖ proportional to the vertical acceleration, and this is supplied as a command value V ₂ to the adder 31.
The command value V ₃ added to the offset command value V _{1 at 1} is supplied to the proportional solenoid 8 of the pressure reducing valve section 5 in the pressure control valve 1.

Next, the operation of the above embodiment will be described. Now, the pressure control unit 4
Assuming that the pilot pressure P _PF from the pressure reducing valve unit 5 is not supplied to the pilot pressure chamber 6g, the main spool 6 is urged downward by the offset spring 6l, so that the land 6a causes the input port 2c to move. The closed state is released, whereby the line pressure P _L maintained at a predetermined value from the hydraulic power source 13 is supplied to the input / output port 2d via the annular groove 6d, which is the active suspension 1.
5 is supplied to the pressure chamber 21d of the hydraulic cylinder 21. At this time, the hydraulic oil supplied from the hydraulic pressure source 13 into the annular groove 6d is supplied to the feedback chamber 6h through the communication passage 6f, so that the pressure in the feedback chamber 6h rises and the main spool 6 is moved to the offset spring 6l. The input port 2c is closed by the land 6a, the main spool 6 is maintained at a position where the biasing force of the offset spring 6l and the pressing force of the pressure in the feedback chamber 6h are balanced, and the output from the input / output port 2d is output. The controlled control pressure P _C is low.

In this state, for example, assuming that the vehicle is traveling at a constant speed on a flat and smooth road without unevenness, the vertical acceleration detector 27 does not oscillate such as pitch, roll and bounce in the vehicle body in this traveling state. The vertical acceleration detection signal ‖ is substantially zero, and the vertical speed calculated value ‖ obtained by integrating this signal by the integrating circuit 30 is also zero. Therefore, the control device 28 outputs the offset pressure command value V ₁ output from the offset pressure setting circuit 29.
A command value V ₃ consisting of nothing is output, and this is supplied to the proportional solenoid 8 of the pressure reducing valve unit 5.

Then, since the proportional solenoid 8 is energized, the actuator 8a is lowered by an amount corresponding to the command value V ₃ supplied thereto, and the spool 7 is lowered against the offset spring 9. Therefore, the blocked state of the input port 3b by the land 7a of the spool 7 is released, and the input port 3b is released.
The feedback chamber 7f and the annular groove 7c and the communication passage 7d.
Is communicated via. At this time, since the control pressure P _C output from the input / output port 2d of the main pressure control unit 4 is supplied to the input port 3b of the pressure reducing valve unit 5, the pressure P _PF of the feedback chamber 7f rises, In response to this, the spool 7 is raised and the land 7a closes the input port 3a.

Here, the pressure P _PF of the feedback chamber 7 f is the cross-sectional area of the lower end surface of the spool 7 is A _PF , the thrust of the proportional solenoid 8 is F _S , and the setting force of the offset spring 9 is f _PS.
Then, the pressure is adjusted according to the following equation.

P _PF = (F _S −f _PS ) / A _PF (1) This pressure P _PF of the feedback chamber 7f is introduced as pilot pressure into the pilot pressure chamber 6g of the main pressure control unit 4 via the fixed throttle 10. As the internal pressure increases, the main spool 6 descends, whereby the closed state of the input port 2c by the land 6a is released,
The line pressure P _L from the hydraulic pressure source 13 is supplied to the input / output port 2d via the annular groove 6d, and the control pressure P _C thereof is controlled to a predetermined offset pressure P _O. Then, this control pressure P _C
Is supplied to the pressure of the pressure chamber 21d of the hydraulic cylinder 21, and the pressure is controlled to the offset pressure P _O.

At this time, since the line pressure P _L input to the annular groove 6d is introduced into the feedback chamber 6h via the communication passage 6f, the pressure in the feedback chamber 6h rises, and the set force of the offset spring 6l and the pilot pressure are increased. P
_The main spool 6 is raised against the pressing force based on _PP , and the land 6a closes the input port 2c.

Therefore, the control pressure P _C of the main spool 6 is obtained when the cross-sectional area of the feedback chamber 6h is A _MF , the cross-sectional area and pressure of the pilot pressure chamber are A _PP and P _PP , and the set force of the offset spring 6l is f _MS. The pressure is adjusted as expressed by the following equation (2).

P _C = (A _PP · P _PP + f _MS ) / A _MF (2) Further, in the damper chamber 6i at the lower end of the main spool 6,
The back pressure P _R is applied via the fixed throttle 6k. The fixed throttle 6k has a function of suppressing a sudden movement of the main spool 6 because it causes a pressure difference with respect to the flow rate fluctuation of the damper chamber 6i accompanying the movement of the main spool 6.

Considering this back pressure P _R , the control pressure P _C is
It can be expressed by equation (3).

P _C = {(A _PP · P _PP + f _MS ) − (A _PP −A _MF ) · P _R } / A _MF (3) At this time, in a steady state where there is no change in the attitude of the vehicle, Since the command value V ₃ is maintained at the offset command value V ₁ and the thrust of the proportional solenoid 8 of the pressure reducing valve unit 5 is maintained at a constant value, the pressure P _PF of the feedback chamber 7f of the pressure reducing valve unit 5 and the main pressure P _PF Since the hydraulic oil does not move between the control valve 4 and the pilot pressure chamber 6g, the pressures in both chambers 7f and 6g are equal (P _PF = P _PP ). In this steady state, the control pressure P _C can be expressed by the following expression (4) from the expressions (1) and (3).

Therefore, the control pressure P _C can be almost set by appropriately selecting the parameter of the second term on the right side of the following equation (4). Can be

Here, the cross-sectional area _{A PP} pilot pressure chamber 6g is much larger than the product _A MF · _{A PF} of the cross-sectional area of the feedback chamber 6h and _{7f (A PP ‖A MF · A} PF), proportional solenoid With respect to the thrust force F _{S of} 8, the control pressure P _C can obtain a high pressure.

Since the control pressure P _C is supplied to the hydraulic chamber 21d of the hydraulic cylinder 21 of the active suspension 15, a thrust force corresponding to the offset pressure P _O is generated in the hydraulic cylinder 21 to cause the vehicle body side member 22 and the wheel side. The space between the members 23 is controlled to be in a neutral state.

In this state, when the tire rides on the road surface convex portion and a vibration input of a relatively low frequency corresponding to the sprung resonance frequency range is input to the pressure chamber 21d via the wheel side member 23 and the piston rod 21b, Due to this vibration input, the pressure in the pressure chamber 21d is increased, and the increased pressure is transmitted to the main pressure control unit 4 through the hydraulic pipe 14.

For this reason, the pressure in the feedback chamber 6h of the main pressure control unit 4 rises, so that the main spool 6 moves to the pilot pressure P.
It further rises against the pressing force of the _PP and the offset spring 6l, whereby the annular groove 6d and the drain port 2
There is communication with e. Therefore, the hydraulic oil in the pressure chamber 21d of the hydraulic cylinder 21, the hydraulic pipe 14 and the annular groove 6d is returned to the oil tank 18, and in response to this, the amount of increase in pressure due to riding on the road convex portion is reduced. At this time, due to the movement of the main spool 5, back pressure P _R is supplied to the damper chamber 6i via the fixed throttle 6k to give a damping force to the main spool 6, and the pilot pressure chamber 6g is boosted. For the boosted amount, the hydraulic oil in the pilot pressure chamber 6g is fixed in the throttle 1.
0 is supplied to the feedback chamber 7f of the pressure reducing valve section 5, the feedback chamber 7f is cut off from the ports 3b and 3c, and the confined spool 7 is raised to raise the annular groove 7c.
Is opened, the oil is returned to the oil tank 18 through the communication passage 7d and the drain port 3c. Therefore, the movement of the main spool 6 is not hindered.

Then, the pressure P _MF of the feedback chamber 6h decreases as the amount of pressure increase due to riding on the road convex portion decreases, and the main spool 6 lowers accordingly, and when the control pressure P _C becomes the offset pressure P _O , the land 6 b is reached. The drain port 2e is closed by this.

Thus, when the main spool 6 is lowered, since the pilot pressure P _PP in pilot pressure chamber 6g is reduced, the spool 7 of the pressure reducing valve portion 5 is lowered from the neutral position, the input port 3b and the feedback chamber 7f Are communicated with each other through the annular groove 7c of the spool 7 and the communication passage 7d, and the control pressure P
_{Since C} is supplied to the feedback chamber 7f, the above (1)
The pressure of the feedback 7f is adjusted according to the formula.

Further, since the fixed throttle 10 is provided between the pilot pressure chamber 6g and the feedback chamber 7f, the pressure P of the pilot pressure chamber 6g generated by the movement of the main spool 6 is increased.
The pressure change of _PP is attenuated and transmitted to the pressure P _PF of the feedback chamber 7f.

Further, the vibration input of the relatively high frequency corresponding to the unsprung resonance frequency range due to the fine unevenness of the road surface is applied to the hydraulic cylinder 21.
Is transmitted to the pressure chamber 21d of the pressure control valve 1 in this case, the pressure fluctuation of the pressure chamber 21d due to the vibration input is absorbed by the fixed throttle 25 and the accumulator 26 and is not transmitted to the pressure control valve 1. The main spool 6 is never activated.

From this constant speed running state, for example, a brake pedal (not shown) is depressed to bring the vehicle into a braking state, and when a nose dive occurs in the vehicle body, the upper and lower parts mounted on the vehicle body side member 15 corresponding to the active suspension on the front wheel side. The acceleration detector 27 outputs a vertical acceleration detection signal ‖ having a positive value corresponding to the posture change of the vehicle body. Therefore, the integration circuit 30 of the control device 28 outputs the posture change suppression command value + V _{2 which} is the vertical velocity calculated value Kn · ‖ obtained by integrating the vertical acceleration detection signal ‖, and this is added to the offset command value V ₁ by the adder 31. It is added and supplied to the proportional solenoid 8 as a command value V ₃ . Therefore, since the thrust force F _S is increased, the spool 7 of the pressure reducing valve unit 5 is lowered from the neutral position, which increases the pressure in the feedback chamber 7f as described above, and accordingly, the main pressure control unit is increased. 4 pilot pressure chamber 6g
, The main spool 6 goes down,
The control pressure P _C is increased according to the equation (5). In this way, when the control pressure P _C increases, the hydraulic cylinder 21
The pressure in the pressure chamber 21d also increases, and as a result, the hydraulic cylinder 21 generates an urging force against the change in the posture of the vehicle body to suppress the change in the posture of the vehicle body.

On the contrary, when the vehicle body side member 22 is raised, a negative vertical acceleration detection signal is output from the vertical acceleration detector 27 in response to this, so that the command value V ₃ for the proportional solenoid 8 is offset to the offset command value V _1. Further, the pressure P _PF of the feedback chamber 7f of the pressure reducing valve unit 4 is reduced accordingly, and the pilot pressure P _PP of the pilot pressure chamber 6g of the main pressure control unit 4 is reduced, so that the main spool 6 is neutralized. The control pressure P _C is decreased by increasing from the position. In response to this, the pressure in the pressure chamber 21d of the hydraulic cylinder 21 also decreases, so that the generation of the urging force that promotes the rise of the vehicle body side member 22 is suppressed.

Similarly, when the vehicle shifts to a turning state and a roll occurs in the vehicle body, the pressure in the pressure chamber 21d of the hydraulic cylinder 21 is increased with respect to the contraction-side active suspension 15 to increase the extension-side active type. By reducing the pressure of the pressure chamber 21d with respect to the suspension 15, the anti-roll effect can be exerted, and control can also be performed to suppress changes in the attitude of the vehicle body such as bounce and pitch. .

As described above, according to the above-described embodiment, in the steady state in which the main spool 6 is stationary, the pilot pressure P _PP in the pilot pressure chamber 6g of the main pressure control unit 4 is maintained at a constant value, and the pressure is reduced accordingly. Since the pressure P _PF of the feedback chamber 7f of the valve portion 5 is also maintained at a constant value, the land 7a of the spool 7 can block the input port 3b, and the main spool 6 descends to drop the pilot pressure chamber 6g.
Input port 3 only when pilot pressure P _PP of decreases
Since b and the feedback chamber 7f are communicated with each other to consume the control pressure P _C , the consumption of the line pressure P _L from the hydraulic power source 13 can be reduced, and the operation of the hydraulic pump 17 should be stopped at this time. Therefore, the load on the engine can be reduced and the fuel consumption can be improved.

Further, the opening degree between the input port 3b of the pressure reducing valve section 5 and the land 7a of the spool 7 depends on the pressure P of the feedback chamber 7f.
_{Since PF} is determined so as to be balanced with the thrust of the proportional solenoid 8, even when the main spool 6 moves quickly, the space between the input port 3b and the land 7a is sufficiently opened, and the pilot pressure P _PP of the pilot pressure chamber 6g is set. A quick response is possible to maintain constant.

Further, by using the control pressure P _C as the supply pressure to the input port 3b of the pressure reducing valve unit 5, the control pressure P _L is compared with the case where the line pressure P _L from the hydraulic pressure source 13 is directly used.
_When the set pressure of _C is low, the differential pressure at the position of the input port 3b does not become large, the sensitivity of the pressure reducing valve section 5 does not have to be excessively high, and there is an advantage that stability can be improved.

In the above embodiment, the case where the hydraulic cylinder is applied as the actuator has been described, but the present invention is not limited to this, and it goes without saying that other hydraulic cylinders such as a hydraulic cylinder and a pneumatic cylinder can be applied. .

Further, in the above embodiment, the case where the vertical velocity calculation signal obtained by integrating the detection signal of the vertical acceleration detector 27 is applied as the posture change detection value has been described, but the present invention is not limited to this, and the vehicle body side member 22 is not limited thereto. And wheel side member 23
May be detected, and the pressure control valve 1 may be controlled by the differential value of the relative displacement detection signal. Further, the lateral acceleration detector or the longitudinal acceleration detector detects the posture change due to the roll or pitch of the vehicle. However, this may be integrated to control the pressure control valve.

Further, in the above-described embodiment, the case where the main pressure control unit 4 and the pressure reducing valve unit 5 are integrally configured has been described, but the present invention is not limited to this, and both are configured separately, and the pilot pressure chamber 6g and the feedback are provided. The chamber 7f may be communicated with a hydraulic pipe including the fixed throttle 10 or a hydraulic pipe having a predetermined length and pipe diameter set to a predetermined damping rate.

Further, although the invention is applied to the case where the pressure control of the active suspension is performed in the above-mentioned embodiment, the invention is not limited to this, and may be applied to the pressure control of a device using another fluid pressure. Of course.

[Effect of device]

As described above, according to the present invention, the pilot chamber in which the control pressure is supplied to one spool end side of the three-way spool valve and the pilot pressure is supplied to the other spool end side In a pressure control valve that generates a control pressure according to the pilot pressure by forming a pressure chamber, the control pressure is input as a primary pressure, and the input control pressure is reduced by using a pilot spool to reduce the input pressure. A pressure reducing valve for forming pilot pressure is provided, and the pressure reducing valve acts on the pilot spool in the direction of increasing the thrust of the proportional solenoid and feeds back the pilot pressure to reduce the pilot pressure. Since the pressure is proportional to the thrust of the proportional solenoid, the pressure is reduced when pressure is not adjusted. The input flow rate to the valve is cut off, energy consumption can be reduced, responsiveness can be improved, and a fixed throttle is not required on the input side of the pressure reducing valve. It is possible to obtain an effect such that there is little change in responsiveness, and in particular, responsiveness deterioration at low temperatures is small. Furthermore, an extremely large pressure difference is not generated between the control pressure that is the primary pressure of the pressure reducing valve and the pilot pressure that is the secondary pressure, and the pressure is reduced in all regions from the low pressure side to the high pressure side of the control pressure. The sensitivity of the valve can be maintained substantially constant, and the stability of pressure control can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. In the figure, 1 is a pressure control valve, 2 is a main valve housing, 3 is a pressure reducing valve housing, 4 is a main pressure control unit, 5 is a pressure reducing valve unit, 6 is a main spool, 6g is a pilot pressure chamber, 6h is a feedback chamber, 6i is a damper chamber, 6k is a fixed throttle, 6l is an offset spring, 7 is a spool (pilot spool), 7f is a feedback chamber, 8 is a proportional solenoid, 9 is an offset spring, 10 is a fixed throttle, 13
Is a hydraulic power source, 15 is an active suspension, 21 is a hydraulic cylinder, and 21a is a pressure chamber.

Claims (3)

[Scope of utility model registration request] And 1. A main valve housing main spool 6 movable in 2, and the feedback chamber 6h of the control pressure P _C as a biasing force for biasing the main spool 6 in a direction that closes the input port 2c is fed back, A pilot pressure chamber 6g to which the pilot pressure P _PP for biasing the main spool 6 is provided so as to face the biasing force, and is determined based on the pressure difference between the control pressure P _C and the pilot pressure P _PP. Depending on the moving position of the main spool 6, the input port 2c and the input / output port 2d, or the input / output port 2
d and the drain port 2e are communicated, and the pilot pressure P _PP
In the pressure control valve that outputs the control pressure P _C based on the above from the input / output port 2d, the control pressure is input as the primary pressure, and the input control pressure is reduced using the pilot spool 7 to obtain the pilot pressure. A pressure reducing valve 5 to be formed is provided, and the pressure reducing valve 5 is provided with respect to the pilot spool 7.
The thrust of the proportional solenoid 8 acts in a direction to increase the pilot pressure, and the pilot pressure is fed back to act in a direction to reduce the pilot pressure to generate a pressure proportional to the thrust of the proportional solenoid 8. Characteristic pressure control valve. 2. The pressure control valve according to claim 1, wherein the pilot pressure of the pressure reducing valve 5 is supplied to the pilot pressure chamber 6g through the throttle 10. 3. The spool comprises a land 6a facing the feedback chamber 6h, a land 6b facing the pilot pressure chamber 6g, and a land 6c connected to the land 6a and having a diameter smaller than that of the land 6c. 3. The pressure control valve according to claim 1, wherein a damper chamber 6i into which a drain pressure is introduced via a throttle 6k is formed by the main valve housing 2 and the main valve housing 2.