JPH09101826A - Pressure proportional control valve and method for controlling pressure of the control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain quick and highly accurate pressure control for a load with different capacity by compensating a real pressure signal by pilot pressure when real pressure is controlled at object pressure. SOLUTION: When a load L is connected and an object pressure signal Vs is outputted from an external device 40a, a compensation part 44 inputs a real pressure signal Vo from a pressure sensor 38 and outputs a compensation signal ΔVcs to an adder 45, which outputs an added value between the signal ΔVcs and the real pressure signal V, to a subtractor 41 as a compensated pressure signal Vc. The subtractor 41 outputs a deviation signal 6V, obtained by subtracting the compensated pressure signal Vc from the object pressure signal V, to a PWM circuit 43 through an amplifier 42 to control the open of an air feeding solenoid valve 30 or an exhausting solenoid valve 31 and control the pilot pressure Pp of a main valve 120. During the control of the pilot pressure Pp at the object pressure Ps , the deviation signal ΔVo becomes a signal subtracting a minimum compensation signal ΔVcs in accordance with the capacity of the load L, so that the pilot pressure Pp is quickly controlled in accordance with the load L and the real pressure Po is controlled at the object pressure Ps .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the fluid pressure on the output side and changes the pilot pressure based on the pressure detection signal to operate the main valve to control the output pressure to a set pressure. The present invention relates to a pressure control method and a pressure control device in the pressure proportional control valve.

[0002]

2. Description of the Related Art A pressure proportional control valve for operating a main valve by a pilot system is internally provided with a control unit for controlling an output pressure to a target pressure PS. This control unit inputs a target pressure signal VS corresponding to the target pressure PS from the outside, and calculates the deviation between this target pressure signal VS and the actual pressure signal VO corresponding to the actual output pressure (hereinafter referred to as the actual pressure) Po. A certain deviation signal .DELTA.V (= VS-VO) is obtained. Then, the control unit controls the pilot pressure PP on the basis of the deviation signal ΔV. That is, the actual pressure signal VO is fed back, and the actual pressure VO
Is controlled to match the target pressure PS, and the pilot pressure PP is controlled to control the actual pressure PO to the target pressure PS.

As a pressure proportional control valve of this type, there is a pressure proportional control valve (electropneumatic regulator) proposed in Japanese Patent Laid-Open No. 2-284213. In this pressure proportional control valve, pilot pressure for operating the main valve is controlled by a pair of solenoid valves for air supply and exhaust. In this pressure proportional control valve, the solenoid valve for air supply or exhaust is controlled to open based on the deviation signal .DELTA.V between the target pressure signal VS and the actual pressure signal VO at that time to control the pilot pressure PS. Then, the main valve is operated by the operating force generated by the difference between the pilot pressure PS and the actual pressure P0, and the actual pressure P0 becomes the target pressure Ps.

However, with this pressure proportional control valve, the greater the load capacity, the more difficult it becomes to control the pilot pressure PS. That is, the larger the load capacity, the longer the time until the actual pressure P0 is controlled to the target pressure Ps. Further, the actual pressure Po may not be controlled to the target pressure PS (so-called overshoot or hunting).

In order to solve such a problem, the present applicant has proposed a pressure proportional control valve disclosed in Japanese Patent Laid-Open No. 19868/1993. FIG. 14 shows the pressure proportional control valve.
This control valve includes a flow passage 1 connecting the outflow port 110 and the pressure sensor 111 to a flow passage 1 communicating with the pilot chamber 113.
14 are formed. An orifice 115 is provided in this flow path 114. When the load capacity is large, it takes a long time for the actual pressure PO to reach the target pressure PS, and the pilot pressure PP in the pilot chamber 113 becomes excessively high. When the pilot pressure PP becomes excessively high, the pilot pressure PP is discharged to the outflow port 110 via the orifice 115. As a result, when the actual pressure P0 reaches the target pressure Ps, the pilot pressure Pp is controlled to an appropriate pressure (approximately the target pressure Ps). Therefore, even if the load capacity is large, the actual pressure P0 can be calculated at high speed and with high accuracy (ie,
The target pressure PS can be controlled (with a short transient response time).

Further, the above publication proposes another pressure proportional control valve shown in FIG. With this pressure proportional control valve,
The outflow port 110 communicates with the feedback chamber 116, and the feedback chamber 116 communicates with the pressure sensor 111 via the flow path 117. And the orifice 11
The flow path 114 provided with 5 is communicated with the flow path 117. In this pressure proportional control valve, the pressure sensor 111 detects the pressure in the feedback chamber 116. Then, when the pilot pressure PP increases, the actual pressure Po introduced into the feedback chamber 116 is increased by the pilot pressure PP, so the pressure detected by the pressure sensor 111 becomes a pressure value higher than the actual actual pressure Po. Become. That is, the pressure detected by the pressure sensor 111 is a pressure obtained by advancing the actual pressure P0 with time. Therefore, by controlling the pilot pressure PP on the basis of the pressure in the feedback chamber 116, the excessive increase of the pilot pressure PP is suppressed more effectively together with the effect of the orifice 115.

Further, the publication proposes another pressure proportional control valve shown in FIG. In this pressure proportional control valve, in addition to the above-mentioned orifice 115, a pressure sensor 118 for detecting the pilot pressure PP is provided in addition to the pressure sensor 111 for detecting the actual pressure PO. Then, when the pilot pressure PP detected by the pressure sensor 118 increases from the actual pressure P0 over a predetermined value, or when the time until the two pressures coincide with each other exceeds a predetermined time, based on the detected pilot pressure PP. Pressure control. As a result, the pilot pressure PP is controlled to an appropriate pressure when the actual pressure PO reaches the target pressure PS,
The actual pressure P0 can be controlled at a higher speed and with higher accuracy.

[0008]

However, in each of the pressure control valves described above, the pilot pressure PP is discharged through the orifice 115 having a constant hole diameter. Therefore, it is impossible to control the pilot pressure PP to an appropriate pressure when the actual pressure PO reaches the target pressure PS for loads having different capacities. Therefore, when the pressure proportional control valve is installed, the pressure proportional control valve is connected to a load that actually controls the pressure, and a confirmation test of the set time is performed. If good control is not performed, the orifice 115 having a hole diameter that allows good control is replaced. Further, the orifice 115
Since the control state changes due to the dimensional error of the hole diameter, an additional confirmation test was required.

Further, as another solution, a servo amplifier may be provided in the control unit, and the servo amplifier may control the drive circuit for driving the solenoid valves for air supply and exhaust. That is, it is possible to adjust the gain of the servo amplifier according to the capacity of the load so that the pilot pressure PP becomes the set pressure when the actual pressure P0 reaches the target pressure Ps.

However, even in this case, it is necessary to adjust the gain of the servo amplifier and test the control state to determine the gain according to the load controlled by the user. Therefore, the adjustment requires knowledge about control, and the confirmation test must be repeated many times, so that the adjustment work cannot be easily performed.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to control loads of different capacities without requiring control knowledge or adjustment work requiring a great amount of work time. A pressure control method and a pressure proportional control valve in a pressure proportional control valve capable of performing high-speed and highly accurate pressure control.

[0012]

In order to solve the above problems, the invention according to claim 1 operates a main valve for controlling an actual pressure supplied to a load by opposition to a feedback pressure of the actual pressure. The proportional pressure control that controls the actual pilot pressure to the target pressure by controlling the deviation between the target pressure signal corresponding to the target pressure and the actual pressure signal that is the detected value of the actual pressure to be small. In the pressure control method for the valve, when the actual pressure is controlled to the target pressure, the actual pressure signal is compensated so that the pilot pressure is controlled to a pressure that is in balance with the feedback pressure with respect to the target pressure.

Further, according to the second aspect of the present invention, the pilot pressure for operating the main valve for controlling the actual pressure supplied to the load by opposition to the feedback pressure of the actual pressure is set as the target pressure corresponding to the target pressure. In the pressure control method in the pressure proportional control valve, which controls the deviation between the signal and the actual pressure signal that is the detected value of the actual pressure to be small, and controls the actual pressure to the target pressure. Generate a compensation component signal that is proportional to the product of the rate of change and a correction amount that is set in advance according to the load capacity, add this compensation component signal to the actual pressure signal to generate the compensation pressure signal, and then set the target pressure. The pilot pressure is controlled based on the deviation between the signal and the compensation pressure signal.

According to the invention of claim 3, in the operation of the invention of claim 2, the correction amount is changed according to the load capacity based on the rate of change of the actual pressure signal.
Further, in the invention according to claim 4, the pilot pressure for operating the main valve for controlling the actual pressure supplied to the load by the pressure opposing to the feedback pressure of the actual pressure is set to the target pressure signal corresponding to the target pressure. In the pressure control method of the pressure proportional control valve, which controls the actual pressure to the target pressure by controlling the deviation from the actual pressure signal that is the detected value of the pressure, the target pressure signal and the actual pressure signal And a first deviation signal that is a deviation between the first deviation signal and a pilot pressure detection signal that is a detection value of pilot pressure and the actual pressure signal. The second deviation signal, which is the deviation from the operating force signal, is obtained, and the pilot pressure is controlled so as to reduce the second deviation signal.

Further, according to the invention of claim 5, a pressure sensor for detecting an actual pressure and outputting an actual pressure signal corresponding to the actual pressure, a pilot pressure adjusting means for adjusting the pilot pressure, and a target pressure are set. A subtraction unit for inputting a corresponding target pressure signal and the actual pressure signal to obtain a deviation signal between the target pressure signal and the actual pressure signal, and a control for controlling the pilot pressure adjusting means so that the deviation signal becomes small. And a rate of change of the actual pressure signal,
Compensation means for outputting a compensation component signal proportional to a product of a preset correction amount according to the capacity of the load, and the compensation component signal is added to the pressure detection signal to generate a compensation pressure signal,
The subtraction unit outputs the compensation pressure signal to the subtraction unit, and the subtraction unit subtracts the compensation pressure signal from the target pressure signal to obtain the deviation signal.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the compensating means differentiates the actual pressure signal and outputs a differential signal proportional to the rate of change thereof, and Compensation component signal generating means for generating a compensation component signal by multiplying the differential signal output by the differentiating component by the compensation amount, and the compensation amount previously set according to the capacity of the load based on the change rate of the actual pressure signal. The correction amount changing means is changed to.

According to a seventh aspect of the present invention, in the invention according to the fifth aspect, the compensating means differentiates the actual pressure signal and outputs a differential signal proportional to a rate of change thereof, and the differential circuit, The differential signal output from the differentiating means is composed of a microcomputer unit for generating a compensation component signal by multiplying a correction amount preset according to the capacity of the load, and the microcomputer unit is configured to change the rate of change of a plurality of different actual pressure signals. A storage unit that stores correction amount data including a correction amount set in advance for each change rate,
It comprises a correction amount setting means for obtaining a change rate of an actual pressure signal obtained with respect to a test pressure signal input in advance and obtaining a correction amount corresponding to the obtained change rate from the correction amount data.

Further, the invention according to claim 8 is driven by an operating force generated by the facing relationship between the pilot pressure and the actual pressure, and the main valve for controlling the actual pressure and the actual pressure are detected to detect the actual pressure. A first pressure sensor that outputs an actual pressure signal corresponding to the pressure and a pilot pressure adjusting unit that adjusts the pilot pressure are provided, and the pilot pressure adjusting unit is based on the target pressure signal corresponding to the target pressure and the actual pressure signal. Is operated to control the pilot pressure to operate the main valve, and the pilot pressure is detected in the pressure proportional control valve that controls the actual pressure to the target pressure,
A second pressure sensor that outputs a pilot pressure detection signal corresponding to the pilot pressure, and an operation force signal generation unit that generates an operation force signal corresponding to the operation force acting on the main valve from the actual pressure signal and the pilot pressure detection signal. And a first subtraction unit that generates a first deviation signal between the target pressure signal and the actual pressure signal, and a second subtraction unit that generates a second deviation signal between the first deviation signal and the operating force signal. And pilot pressure control means for controlling the pilot pressure adjusting means based on the second deviation signal.

Therefore, according to the first aspect of the present invention,
When the actual pressure is controlled to the target pressure, the actual pressure signal is compensated so that the pilot pressure is controlled to a pressure that balances the feedback pressure with respect to the target pressure. As a result, once the actual pressure is controlled to the target pressure, the pilot pressure increases beyond the pressure that is in balance with the feedback pressure of the target pressure, so that the main valve is operated and the actual pressure exceeds the target pressure. Things will disappear. Therefore, by changing the compensation amount for the actual pressure signal according to the capacity of the load, it becomes possible to perform appropriate pressure control even for loads of different capacities.

According to the second aspect of the invention, the compensating pressure signal is generated by adding the compensating component signal corresponding to the load capacity to the actual pressure signal. Therefore, the deviation signal is a signal whose magnitude is suppressed more than the difference between the target pressure signal and the actual actual pressure signal. By controlling the pilot pressure with this deviation signal, even if it takes time for the actual pressure to reach the target pressure, the pilot pressure becomes a pressure that balances with the target pressure when the actual pressure reaches the target pressure. Can be controlled.

Furthermore, the compensation component signal is obtained as an amount proportional to the product of the rate of change of the actual pressure signal and a correction amount preset according to the load capacity. When the actual pressure signal approaches the target pressure signal, the deviation becomes smaller, so the rate of change of the actual pressure signal becomes smaller. Therefore, when the actual pressure reaches the target pressure, the rate of change approaches 0, and the compensation component signal approaches 0. As a result, the deviation approaches 0 when the actual pressure reaches the target pressure, and the amount of change in pilot pressure at that time becomes small. Therefore, when the actual pressure approaches the target pressure, the pilot pressure can be controlled to the target pressure with high accuracy.

Since the compensating component signal is set according to the capacity of the load, as long as the pilot pressure is controlled to a pressure that balances the target pressure when the actual pressure first reaches the target pressure, the compensating component signal is controlled. The value of the signal can be set to a minimum. As a result, the pilot pressure is rapidly controlled according to the capacity of the load based on the large deviation compensated by the minimum compensation component signal, so that the actual pressure is rapidly controlled toward the target pressure. Therefore, it becomes possible for the user to control the actual pressures of the loads having different capacities to the target pressure at high speed and with high accuracy, without the user having to adjust the control characteristics of the pilot pressure according to the capacities of the loads.

According to the invention of claim 3, according to claim 2,
In addition to the effect of the invention described in (1), it becomes possible to automatically set the correction amount according to the capacity of the load. According to the invention described in claim 4, the pilot pressure is controlled so that the second deviation signal, which is the deviation between the first deviation signal and the operating force signal, becomes zero. That is, the pressure deviation, which is the first deviation signal, and the operating force, which is the second deviation signal, are controlled to match. As a result, when the first deviation signal becomes small,
Since the operating force is also controlled to be small, the pilot pressure is controlled so that the operating force becomes 0 when the actual pressure reaches the target pressure. Therefore, the actual pressure is controlled to the target pressure with high accuracy regardless of the load capacity. Further, a high operating force can be obtained at the initial stage of control. As a result, the pilot pressure can be brought close to the target pressure rapidly at the initial stage of control, so that the actual pressure is controlled to the target pressure at high speed.

According to the invention described in claim 5, the pressure sensor outputs an actual pressure signal corresponding to the actual pressure. The compensating means generates a compensation component signal from the actual pressure signal, and the adder produces a compensation pressure detection signal by adding the compensation component signal to the actual pressure signal. The subtraction unit subtracts the compensation pressure signal from the target pressure signal to obtain the deviation signal. Therefore, the obtained deviation signal has a signal value whose magnitude is suppressed as compared with the case where no compensation is performed. When the control means controls the pilot pressure adjusting means with this deviation signal, it becomes possible to control the pilot pressure to a pressure value in which the pilot pressure is balanced with the target pressure when the actual pressure reaches the target pressure. Further, the compensation component signal is generated as an amount proportional to the product of the rate of change of the actual pressure signal and a correction amount preset according to the load capacity. As a result, the deviation signal becomes smaller as the actual pressure signal approaches the target pressure signal, so the rate of change of the actual pressure signal becomes smaller. Therefore, when the actual pressure reaches the target pressure, the differential signal approaches 0, and the compensation component signal approaches 0. Therefore, when the actual pressure reaches the target pressure, the deviation signal approaches 0, and the change amount of the pilot pressure at that time becomes small. Therefore, when the actual pressure approaches the target pressure, the pilot pressure can be controlled to the target pressure with high accuracy. Since the compensation component signal is set according to the capacity of the load, as long as the pilot pressure is controlled to a pressure that balances the target pressure when the actual pressure first reaches the target pressure, the value of the compensation component signal is set. Can be set to a minimum. As a result, the pilot pressure is rapidly controlled according to the load capacity by the large deviation signal compensated by the minimum compensation component signal, so that the actual pressure is rapidly controlled toward the target pressure. Therefore, the user can control the actual pressures of the loads having different capacities to the target pressure at high speed and with high accuracy, without the user having to adjust the control characteristics of the pilot pressure according to the capacities of the loads.

According to the invention of claim 6, claim 5
In addition to the effect of the invention described in (1), the rate of change of the actual pressure is obtained as a differential signal of the differentiating circuit, and the differential signal is multiplied by the correction amount signal generating means to generate a compensation amount signal. The correction amount changing unit changes the correction amount to a value according to the load capacity based on the change rate of the actual pressure. Therefore, it is possible to easily configure the circuit using a differentiating circuit or the like.

According to the invention of claim 7, claim 5
In addition to the effect of the invention described in (3), the microcomputer unit obtains the change rate of the actual pressure signal obtained with respect to the test pressure signal input in advance, and stores the correction amount corresponding to the load capacity based on this change rate. It is calculated from the correction amount data of the copy. In this way, a correction amount according to the capacity of the load is set in advance, and in the pressure control of this load, a compensation component signal is generated from the set correction amount and the change rate of the actual pressure signal. Therefore, the microcomputer can be used to set the correction amount according to the capacity of the load, so that the control unit can be easily configured.

According to the invention described in claim 8, the second deviation signal which is a deviation between the first deviation signal and the operating force signal is 0.
Since the pilot pressure is controlled so that when the actual pressure approaches the target pressure and the first deviation signal decreases, the operating force is also controlled to decrease. Then, when the actual pressure reaches the target pressure, the pilot pressure is controlled so that the operating force becomes zero. As a result, the actual pressure is controlled to the target pressure with high accuracy regardless of the load capacity. Further, a high operating force can be obtained at the initial stage of control. As a result, the pilot pressure can be brought close to the target pressure rapidly, so that the actual pressure is controlled to the target pressure at high speed.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 4 shows the structure of the electromagnetic proportional control valve 1.
The electromagnetic proportional control valve 1 includes a first housing 2, and a flow path 3 extending in the up-down direction is formed inside the first housing 2. The flow path 3 is in communication with the outside through an inflow port 4, an outflow port 5 and an exhaust port 6. A valve seat 7 is formed in the flow passage 3 between the inflow port 4 and the outflow port 5, and a valve seat 8 is formed in the flow passage 3 between the outflow port 5 and the exhaust port 6. The inflow port 4 is supplied with air having a high supply pressure PI from an external air supply source (not shown).

A valve housing 9 is arranged at the lower end of the flow path 3,
The valve body 11 is accommodated in the accommodation chamber 10 of the valve accommodation body 9 so as to be vertically slidable. The valve body 11 is arranged at a position where the upper surface of the valve body 11 comes into contact with the valve seat 7 by the return spring 12 arranged in the accommodation chamber 10 (hereinafter, this state is referred to as an air supply closed position). In addition, the valve body 11 is formed with a communication hole 11 a for communicating the flow path 3 with the storage chamber 10. Therefore,
Since the air in the storage chamber 10 is communicated with the flow passage 3 and the pressure in the storage chamber 10 is maintained at the pressure in the flow passage 3, the valve body 11 moves smoothly.

A second housing 15 is arranged above the first housing 2. A valve accommodating portion 16 is formed at the center of the lower surface of the second housing 15, and the valve accommodating portion 16 is fitted and inserted in the upper portion of the flow path 3. This valve housing 16
A valve element 18 is accommodated in the accommodation chamber 17 so as to be vertically slidable. The valve body 18 is arranged at a position (hereinafter, this state is referred to as an exhaust position) where the lower surface of the valve body 18 comes into contact with the valve seat 8 by a return spring 19 arranged in the accommodation chamber 17.

A rod 20 penetrating the valve body 18 and the second housing 15 is disposed in the flow path 3. Rod 2
A ring 21 is fixed at a position facing the lower surface of the valve body 18 in the outer peripheral portion of 0. The ring 21 allows the rod 20 to move downward with respect to the valve body 18 and also to move upward together with the valve body 18.
A communication hole 22 that communicates the flow path 3 with the storage chamber 17 is formed in the rod 20. Then, the inside of the accommodation chamber 17 is maintained at the pressure of the flow path 3. As a result, the valve body 18 moves smoothly. When the rod 20 moves downward, the rod 20 moves the valve body 11 downward. Further, the rod 20 is arranged at a position (hereinafter, referred to as a neutral position) for maintaining the valve body 11 at the air supply closed position and the valve body 18 at the exhaust gas closed position.

When the rod 20 moves downward from the neutral position, the rod 20 moves the valve body 11 downward from the air supply closing position. Then, the inflow port 4 and the outflow port 5 are communicated with each other via the valve seat 7. At this time, the valve 1
The exhaust port 8 is arranged in the exhaust closed position so that the outflow port 5 and the exhaust port 6 are isolated from each other. Conversely, when the rod 20 moves upward from the neutral position, the ring 21 engages the valve body 18 and the rod 20 moves the valve body 18 upward from the exhaust closed position. Then, the outflow port 5 and the exhaust port 6 are communicated with each other via the valve seat 8. At this time, the valve body 11 is arranged at the air supply closed position, and the inflow port 4 and the outflow port 5 are isolated. The valve body 11, 18 and the rod 20 constitute a main valve 120.

A feedback chamber 23 is formed in the upper part of the second housing 15, and the feedback chamber 23 is connected to the outflow port 5 via a flow path 24. A third housing 25 is arranged above the second housing 15. A pilot chamber 26 is formed below the third housing 25 so as to face the feedback chamber 23. Feedback room 23 and pilot room 26
A diaphragm 27 is arranged at the boundary with the pair of pressure plates 28 on the upper end of the rod 20.
It is clamped and fixed by. The pressure receiving area of the diaphragm 27 on the pilot chamber 26 side and the pressure receiving area of the feedback chamber 23 on the diaphragm 27 are formed to be equal. Therefore, the pressure in the pilot chamber 26 (hereinafter referred to as pilot pressure PP)
And the pressure in the feedback chamber 23 (hereinafter referred to as feedback pressure PF) are equal, the diaphragm 27
Is placed at a position (hereinafter, referred to as a neutral position) where the operating force does not act and the diaphragm 27 is not deformed. And
When the diaphragm 27 is in the neutral position, the rod 20
Is also placed in the neutral position.

Therefore, when the pilot pressure PP is higher than the feedback pressure PF, a downward operation force acts on the rod 20 and air is supplied from the inflow port 4 to the outflow port 5. On the contrary, when the pilot pressure PP is lower than the feedback pressure PF, an upward operating force acts on the rod 20 and air is exhausted from the outflow port 5 to the exhaust port 6.

On the upper surface of the third housing 25, an air supply solenoid valve 30 and an exhaust solenoid valve 31 are arranged. Both solenoid valves 30 and 31 are shielded from the outside by a cover 32 arranged on the third housing 25. The inside of the cover 32 is communicated with the outside through a communication hole 33. In the present embodiment, the air supply solenoid valve 30 and the exhaust solenoid valve 3
1 configures pilot pressure adjusting means.

The air supply solenoid valve 30 is in communication with the inflow port 4 via a flow path 34, and is also in communication with the pilot chamber 26 via a flow path 35. The inflow port 4 communicates with the pilot chamber 26 only while the air supply solenoid valve 30 is controlled to be opened. The exhaust electromagnetic valve 31 controls opening / closing of a flow path 36 that connects the pilot chamber 26 and the cover 33. The electromagnetic valve 31 for exhaust makes the pilot chamber 26 communicate with the inside of the cover 33, that is, the outside air only while being controlled to be opened. In addition, each solenoid valve 3
0 and 31 are respectively connected to a control unit 37 arranged in the cover 33.

A pressure sensor 38 is arranged above the third housing 25. The feedback pressure PF is applied to the pressure receiving surface of the pressure sensor 38 via the flow path 39. The pressure sensor 38 controls the feedback pressure P
F, that is, the actual pressure signal VO corresponding to the pressure (actual pressure P0) of the outflow port 5 is output to the control unit 37.

Next, the structure of the controller 37 will be described. FIG.
Shows a pressure proportional control valve block diagram. Control unit 37
Is a subtracter 41 as a subtraction unit, an amplifier 42, a pulse width modulation circuit unit (hereinafter, PWM (Pulse Width Modulation)
The circuit section 43, a compensation section 44, and an adder 45 as an addition section. The PWM circuit section constitutes a control means, and the compensating section 44 constitutes a compensating means.

The subtractor 41 receives the target pressure signal VS from the external device 40a. The target pressure signal VS is a signal for designating the pressure of the outflow port 5 to be set (that is, the target pressure PS for special distinction from the actual pressure PO) and is generated by the external device 40a. . or,
The subtracter 41 receives the compensation pressure signal V from the adder 45 described later.
Enter C. The subtracter 41 subtracts the compensation pressure signal VC from the target pressure signal VS and calculates the difference between the deviation signals .DELTA.V (= VS
-VC) to the amplifier 42. The amplifier 42 amplifies the deviation signal ΔV and outputs the amplified signal to the PWM control unit 43 as a control deviation signal ΔVCR.

The PWM circuit section 43 is formed of a known circuit configuration including a carrier triangular wave generation circuit, a comparator, a drive circuit and the like. The PWM circuit unit 43 controls the control deviation signal Δ
A control drive signal VD consisting of a pulse train having a duty ratio uniquely determined with respect to VCR is output to the air supply solenoid valve 30 or the exhaust solenoid valve 31. That is, the PWM circuit unit 43
When the control deviation signal .DELTA.VCR is positive, outputs a control drive signal VD having a duty ratio that increases corresponding to the magnitude of the control deviation signal .DELTA.VCR to the air supply solenoid valve 30.
Further, when the control deviation signal ΔVCR is negative, the PWM circuit section 43 outputs to the exhaust solenoid valve 31 a control drive signal VD having a duty ratio that increases corresponding to the magnitude of the control deviation signal ΔVCR. The air supply side solenoid valve 30 is provided with the inflow port 4 and the pilot chamber 26 only while the control drive signal VD is on.
And communicate with. The exhaust side solenoid valve 31 communicates the pilot chamber 26 with the outside air only while the control drive signal VD is on.

The adder 45 receives the actual pressure signal VO from the pressure sensor 38. The compensator 44 receives the actual pressure signal VO from the pressure sensor 38 and outputs a compensation component signal ΔVCS corresponding to the actual pressure signal VO to the adder 45. The adder 45 adds the actual pressure signal VO and the compensation component signal ΔVCS,
The added value is output to the subtractor 41 as a compensation pressure signal VC (= VO + ΔVCS).

Next, the structure of the compensator 44 will be described in detail. FIG.
As shown in FIG. 4, the compensating section 44 is composed of a differentiating circuit 46 as a compensation component signal generating means and a time constant setting circuit 47 as a correction amount changing means. Also, the time constant setting circuit 4
7 is composed of a differentiating circuit 48, an absolute value circuit 49 and a time constant changing circuit 50 connected in series.

FIG. 3 shows the differentiating circuit 46 and the time constant setting circuit 4.
7 is a circuit diagram showing details of FIG. The differentiating circuit 48 has a known circuit configuration including an operational amplifier 51, a capacitor 52, and a resistor 53. The differentiating circuit 48 differentiates the input actual pressure signal VO with respect to time and outputs the differentiated signal to the absolute value circuit 49. That is, the differentiating circuit 48 determines the actual pressure P
A differential signal, which is a signal of the change amount of O 2 per unit time, is generated.

The actual pressure signal VO has a smaller increasing rate or decreasing rate as the load L having a larger capacity. On the contrary, the actual pressure signal VO has a larger increase rate or decrease rate as the load L having a smaller capacity. Therefore, the differential signal has a smaller positive or negative value as the load L having a larger capacitance. On the contrary, the differential signal has a larger positive or negative value as the load L having a smaller capacitance.

The absolute value circuit 49 includes operational amplifiers 54 and 5
5, the diodes 56 and 57, and the resistors 58 to 63 have a known circuit configuration. The absolute value circuit 49
The absolute value of the input differential signal is taken and the absolute value is output to the time constant changing circuit 50 as a differential absolute value signal. That is, the absolute value circuit 49 generates a signal of the amount of change of the actual pressure signal VO irrespective of the changing direction, that is, a differential absolute value signal.

Therefore, the differential absolute value signal has a larger value as the load L having a larger capacity. On the contrary, the differential absolute value signal has a smaller value as the load L having a smaller capacity. The time constant changing circuit 50 comprises a known electronic volume 50a. The resistance value R of the electronic volume 50a is controlled by the differential absolute value signal. That is, the resistance value R increases as the value of the differential absolute value signal decreases (that is, the load L having a large capacity), and conversely, the value of the differential absolute value signal increases (that is, the load L having a small capacity increases. ) It is controlled to decrease.

The differentiating circuit 46 is formed by a known circuit configuration including an operational amplifier 64, the electronic volume 50a and a capacitor 65. The actual pressure signal VO is input to the inverting input terminal of the operational amplifier 64 via the capacitor 65. Negative feedback is applied between the inverting input terminal and the output terminal of the operational amplifier 64 via the electronic volume control 50a. The non-inverting input terminal of the operational amplifier 64 is grounded. The differentiating circuit 46 differentiates the actual pressure signal VO and adds it as a compensation component signal .DELTA.VCS which is the product of this differential value and the time constant CR which is the product of the resistance value R of the electronic volume 50a and the capacitance C of the capacitor 65. Output to 45.

That is, the differentiating circuit 46 uses the actual pressure signal VO.
The signal obtained by multiplying the rate of change of .DELTA.
It is generating VCS. That is, in this embodiment, the correction amount is configured by the time constant CR of the differentiating circuit 46. Therefore, the time constant CR is set such that the compensation component signal ΔVCS has a larger value as the load L has a larger capacity, and conversely has a smaller value as the load L has a smaller capacity.

The adder 45 is composed of a known differential amplifier circuit including an operational amplifier 66 and resistors 67 to 70. The compensation input signal ΔVCS is input to the inverting input terminal of the operational amplifier 66 via the resistor 67. Also, the operational amplifier 66
The non-inverting input terminal of is connected to the actual pressure signal VO via the resistor 68.
Enter A resistor 70 is connected between the output terminal and the inverting input terminal of the operational amplifier 66, and the non-inverting input terminal is grounded via the resistor 69. That is, the adder 45 generates a signal obtained by adding the compensation amount ΔVCS to the actual pressure signal VO, that is, the compensation pressure signal VC. Therefore, the compensating pressure signal VC output from the adder 45 has the same value as the actual pressure signal VO, and when there is a pressure change, the load L having a larger capacity has a larger value, and conversely, the load L having a smaller capacity has a larger value. It becomes a small value.

The time constant CR set by the time constant setting circuit 47, that is, the relationship of the time constant CR with respect to the differential absolute value signal, is the change amount of the actual pressure signal VO per time, that is,
The value is determined in advance by experiments or the like according to the capacity of the load L. The time constants CR determined in correspondence with the loads L of different capacities thus obtained in the experiments are as follows: the pilot pressure PP is the target pressure when the actual pressure PO first reaches the target pressure PS. As long as it is controlled by PS, that is, as long as no overshoot or undershoot occurs, the minimum value is determined.

That is, the time constant C larger than this minimum value
The compensation pressure signal V is calculated from the compensation component signal ΔVCS obtained by R.
When the pilot pressure PP is controlled by the deviation signal ΔV between the target pressure signal VS and the compensation pressure signal VC, the pilot pressure PP becomes the target pressure PS when the actual pressure PO first reaches the target pressure PS. Controlled. This is because the larger the time constant CR, the smaller the deviation signal ΔVO, and the shorter the average opening time of the solenoid valve 30 for air supply.
The rate of increase in pilot pressure PP decreases. Therefore, the time until the pilot pressure PP reaches the target pressure PS becomes longer, and the time until the actual pressure PO is controlled to the target pressure PS becomes longer. Therefore, in order to minimize the time until the actual pressure P0 is controlled to the target pressure Ps, the time constant CR is such that the pilot pressure Pp is controlled to the target pressure Ps when the actual pressure P0 first reaches the target pressure Ps. The minimum value is set as long as it is performed.

Next, the operation of the pressure proportional control valve configured as described above will be described. When the load L having a certain capacity is connected to the pressure proportional control valve 1 and the target pressure signal VS corresponding to the target pressure PS is output from the external device 40a, the subtractor 41 outputs the compensation pressure signal VC from the target pressure signal VS. The deviation signal ΔV obtained by subtracting is subtracted from PW via the amplifier 42.
It is output to the M circuit unit 43. The PWM circuit unit 43 controls to open either the air supply solenoid valve 30 or the exhaust solenoid valve 31 at a duty ratio corresponding to the deviation signal ΔV.

At this point, the actual pressure P0 is 0 and the compensation pressure signal VC is 0, so the deviation signal .DELTA.V (= VS-
VC = VS-VO-ΔVCS) becomes positive and the solenoid valve for air supply 3
0 is controlled to open. By controlling the opening of the air supply solenoid valve 30,
Supply air PI is introduced into the pilot chamber 26 from the inflow port 4, and the pilot pressure PP increases. Then, the pilot pressure PP becomes larger than the feedback pressure PF, and the downward operating force acts on the diaphragm 27, and the diaphragm 27 moves downward from the neutral position. Then, the rod 20 moves the valve body 11 downward from the air supply closed position,
Supply of air from the inflow port 4 to the outflow port 5 is started.

When air is supplied to the outflow port 5, the actual pressure Po and the feedback pressure PF of the outflow port 5 gradually increase according to the capacity of the load L. Therefore, the actual pressure signal VO from the pressure sensor 38 also rises by the amount of change according to the magnitude of the capacity of the load L. At this time, the time constant setting circuit 47 sequentially sets a time constant CR which is predetermined based on the differential signal of the actual pressure signal VO and corresponding to the change amount of the actual pressure signal VO per unit time. Then, the differentiating circuit 46
Outputs a compensation component signal .DELTA.VCS which is the product of the differential signal of the actual pressure signal VO and the time constant CR at that time.

This compensation component signal .DELTA.VCS is added to the actual pressure signal VO at that time, and the compensation pressure signal VC (= VO + .DELTA.V)
CS) is generated. Therefore, as shown in FIG. 5, the compensation pressure signal VC has a larger value than the compensation pressure signal VC when the compensation indicated by the chain double-dashed line is not performed. As a result, the deviation signal ΔV also has a smaller value than when no compensation is performed.

At the initial stage of control, a large deviation signal Δ
Since the solenoid valve 30 for air supply is controlled by V with a long average opening time, the pilot pressure PP rapidly rises. As a result, downward operation force (illustrated as positive operation force in FIG. 5)
Since VF rises sharply, the actual pressure P0 rises sharply.

When the actual pressure P0 approaches the target pressure Ps and the deviation signal ΔV becomes smaller, the average opening time of the air supply solenoid valve 30 becomes shorter, so the rate of increase of the pilot pressure Pp decreases. As a result, the downward operating force VF decreases, and the actual pressure PO approaches the target pressure PS while the rate of increase decreases.

At this time, the actual pressure P0 is first the target pressure P0.
As long as the pilot pressure PP is controlled to the target pressure PS when it reaches S, the minimum time constant CR is set according to the load L at this time. Therefore, the compensation component signal ΔV
CS has a minimum size according to the load L at this time. That is, the deviation signal Δ obtained from the compensation pressure signal VC
V is a minimum compensation component signal ΔVCS according to the capacity of the load L.
Is subtracted, the magnitude of the signal does not become significantly smaller than the deviation signal ΔV when no compensation is performed. As a result, the air supply solenoid valve 30 is controlled to open with a high average opening time, so that the pilot pressure PP is rapidly controlled to the target pressure PS in accordance with the load L. Therefore, the actual pressure Po is rapidly controlled to the target pressure PS.

When the actual pressure P0 approaches the target pressure Ps, the deviation signal .DELTA.V becomes smaller, so that the rate of increase of the actual pressure signal V0 approaches zero and the differential signal also approaches zero. Therefore, the compensation signal ΔVCS approaches 0, and the deviation signal ΔV gradually converges to 0. As a result, the average opening time of the exhaust electromagnetic valve 31 is shortened and the amount of air exhausted from the pilot chamber 26 is reduced, so that the pilot pressure PP is highly accurate and the target pressure P
Controlled by S. When the actual pressure P0 reaches the target pressure Ps, the pilot pressure Pp and the actual pressure P0 are balanced, and the operating force acting on the diaphragm 27 becomes zero.
As a result, the actual pressure Po is controlled to the target pressure PS with high accuracy.

Next, a case will be described in which a load L having a capacity different from the previous load L is connected to the pressure proportional control valve 1. The actual pressure signal VO output with respect to the target pressure signal VS is the amount of change per time according to its capacity.
Therefore, the time constant CR corresponding to the amount of change in the new actual pressure signal VO is set in the differentiating circuit 46, and the compensation component signal .DELTA.VCS with this time constant CR as the correction amount is output. And
The PWM circuit section 43 controls opening of the air supply solenoid valve 30 or the exhaust solenoid valve 31 by the deviation signal ΔV compensated by the compensation component signal ΔVCS. As a result, even when loads L having different capacities are connected and used, the pilot pressure PP is rapidly controlled to the target pressure PS according to the capacities, and the target pressure is reached when the actual pressure P0 reaches the target pressure PS. Pressure PS
Is controlled. Therefore, even when the capacity of the load L changes, the actual pressure P0 is controlled to the target pressure PS at high speed and with high accuracy according to the capacity of the load L.

According to the pressure proportional control valve of the present embodiment detailed above, the following effects can be obtained. (A) A differential signal of the actual pressure signal VO output by the time constant setting circuit 47 with respect to the input of the target pressure signal VS, that is,
The time constant CR corresponding to the capacity of the load L is set based on the rate of change of the actual pressure signal VO corresponding to the capacity of the load L. Then, the deviation signal ΔV is compensated by the compensation component signal ΔVCS which is the product of the time constant CR and the change rate. This time constant CR is such that when the opening control of the air supply solenoid valve 30 or the exhaust solenoid valve 31 is performed by the deviation signal ΔV compensated by the compensation component signal ΔVCS with the time constant CR as the correction amount, the actual pressure P0 is At the time when the target pressure PS is first reached, the pilot pressure PP is set to a minimum value in advance according to the capacity of the load L as long as it is controlled to the target pressure PS. As a result, the average opening time of the solenoid valve 30 for supply air becomes long and the pilot pressure PP is rapidly controlled to the target pressure PS, so that the actual pressure PO is controlled to the target pressure PS at high speed.

Also, the compensation component signal ΔVCS is set to a time constant CR,
Since it is generated by the product of the rate of change of the actual pressure signal VO, when the actual pressure PO reaches the target pressure PS,
The compensation signal ΔVCS can be set to zero. Therefore, when the actual pressure PO reaches the target pressure PS, the deviation signal .DELTA.V can be gradually converged to 0, so that the pilot pressure PP can be controlled to the target pressure PS with high accuracy. Therefore, the actual pressure Po can be controlled to the target pressure PS with high accuracy. As a result of the above, loads L of various capacities
On the other hand, the actual pressure P0 can be controlled to the target pressure Ps at high speed and with high accuracy without performing control knowledge and adjustment work that requires a great deal of work time.

Further, even when the capacity of the connected load L changes, a new time constant CR is set based on the actual pressure signal VO output according to the new capacity, and this time constant CR is set. The deviation signal ΔV is compensated by the compensation component signal ΔVCS generated by the above. Therefore, even if the capacity of the load L connected to the pressure proportional control valve 1 changes, the pressure control can be performed at high speed and with high accuracy.

(B) Rather than operating the air supply solenoid valve 30 and the exhaust air solenoid valve 31 at the same time to control the pilot pressure PP, the air supply solenoid valve 30 or the air supply solenoid valve 30 is controlled based on the deviation signal ΔV. Since only one of the exhaust electromagnetic valves 31 is operated, air consumption due to control can be suppressed to the minimum.

(C) For the same reason as in (b) above, since the operation of each solenoid valve 30, 31 can be minimized,
The life of each solenoid valve 30, 31 can be extended. (D) Since an expensive member such as an orifice having a particularly high dimensional accuracy is not used, the cost can be reduced.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. In this embodiment, the input signal switching unit 80 is provided in the preceding stage of the subtractor 41 in the first embodiment,
The difference from the first embodiment is that the differential constant setting unit 47 is replaced with a microcomputer unit 81 including a one-chip microcomputer. Therefore, the input signal switching unit 80 and the microcomputer unit 8
Only one configuration will be described in detail, and the same configurations as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, the input signal switching section 80
Is composed of a changeover switch 82 and a variable resistance portion 83 to which a predetermined voltage Vcc is applied. The variable resistance portion 83 generates the test pressure signal VI from the predetermined voltage VCC. The test pressure signal VI is a signal for determining the time constant CR which is the correction amount for the load L.

The change-over switch 82 is switch-controlled by the microcomputer 81, and the target pressure signal VS from the external device 40a is outputted.
Either one of the terminal to which is input and the terminal connected to the variable resistance portion 83 is connected to the subtractor 41.

The microcomputer section 81 includes a central processing unit (hereinafter,
MPU 84, read-only memory (hereinafter, ROM) 85, readable and rewritable memory (hereinafter,
RAM 86, analog-digital converter (hereinafter referred to as A / D converter) 87, digital-analog converter (hereinafter referred to as D / A converter) 88, and input / output interface (hereinafter referred to as I / O) And 89. The MPU 84 has an input / output interface 8
A changeover switch 82 is connected via 9. Also, M
The external device 40b is connected to the PU 84 via the input / output interface 89. The MPU 84 receives the setting command signal SC from the external device 40b. In the present embodiment, the differentiating circuit 46 and the microcomputer section 81 constitute the compensating section 44 as compensating means. And M
The PU 84 constitutes a correction amount setting means, and the ROM 85 constitutes a storage unit.

The ROM 85 stores a control program for determining the time constant CR of the differentiating circuit 46 based on the test pressure signal VI. Further, the ROM 85 stores correction amount data including a time constant CR for each change rate of the actual pressure signal VO. Each rate of change in the correction amount data is the amount of change per hour of the actual pressure signal VO when the test pressure signal VI is input in the state where the loads L having different capacities are connected, that is, the load L. It is set to the value corresponding to the capacity. The time constant CR is determined in advance by experiments or the like according to the capacity of the load L. That is, the time constant CR corresponding to the differential value equal to the change amount of the actual pressure signal VO of a certain load L over time is compensated by the compensation pressure signal VC which is compensated by the compensation amount signal .DELTA.VCS whose correction amount is this time constant CR. When the deviation signal .DELTA.V is obtained at, the pilot pressure PP is the target pressure P when the actual pressure P.sub.o reaches the target pressure P.sub.S first.
The minimum value is determined as long as it is controlled by S.

The RAM 86 temporarily stores the data of the actual pressure signal VO obtained with respect to the test pressure signal VI. The MPU 84 performs time constant setting processing based on the control program. This time constant setting process is first performed only once when the load L having a certain capacity is connected to the pressure proportional control valve 1 and the supply pressure PI is supplied to the inflow port 4. That is, the MPU 84 calculates the rate of change corresponding to the capacity of the load L from the actual pressure signal VO obtained with respect to the test pressure signal VI with the load L of a certain capacity connected. Then, the MPU 84 obtains the time constant CR corresponding to the calculated change rate from the correction amount data stored in the ROM 85. Further, the MPU 84 outputs to the differentiating circuit 46 a time constant setting signal for setting the calculated time constant CR as the time constant CR of the differentiating circuit 46. Here, the calculated time constant setting signal is stored and held in a non-volatile memory or the like (not shown). In this way, after the time constant setting process is performed and the time constant CR corresponding to the capacity of the load L is determined in the differentiating circuit 46, the time constant CR is used for pressure control by the target pressure signal VS when actually operating. used. That is, in the differentiating circuit 46, the electronic volume 50a is controlled by the time constant setting signal from the microcomputer 81 and is set to the time constant CR based on the time constant setting signal.

The external device 40b is connected to the microcomputer 81 and outputs to the microcomputer 81 a test command signal SC for executing the above-mentioned time constant setting processing. next,
The operation of the pressure proportional control valve configured as described above will be described with reference to the flowchart shown in FIG.

After the load L having a certain capacity is connected to the pressure proportional control valve 1 and the supply pressure PI is supplied to the inflow port 4,
When the test command signal SC is input from the external device 40b (step 1, hereinafter simply referred to as S1), the MPU 84 makes R
The time constant setting signal (hereinafter referred to as the minimum time constant setting signal) having the minimum value among the time constants CR of the data table stored in the OM 85 is passed through the D / A converter 88 to the differentiating circuit 4.
It outputs to 6 (S2). As a result, the minimum value is set as the time constant CR of the differentiating circuit 46. Where the time constant C
The reason why R is set to the minimum is to know the capacity of the load L by obtaining the actual pressure signal VO in the state in which the compensation is not performed by minimizing the compensation component signal ΔVCS for the actual pressure signal VO by the test pressure signal VI. is there. Therefore, originally, it is desirable to set the time constant CR to 0 and the compensation component signal ΔVCS to 0, but it is difficult to set the time constant CR to 0 because of the circuit configuration. Therefore, set it to the minimum value. I have to.

Next, the MPU 84 switches the changeover switch 82 to the variable resistance section 83 and outputs the test pressure signal VI set by the variable resistance section 83 to the subtractor 41 (S).
3). When the PWM control circuit unit 43 controls the open air solenoid valve 30 or the exhaust solenoid valve 31 to open based on the deviation signal ΔV between the test pressure signal VI and the actual pressure signal VO, the actual pressure P
O increases at an increasing rate according to the capacity of the load L. And
The pressure sensor 38 outputs an actual pressure signal VO having a characteristic corresponding to the capacity of the load L.

Next, the MPU 84 outputs the actual pressure signal VO
A / D converted data by the A / D converter 87 is stored in the RAM 8
6 (S4). Therefore, this actual pressure signal VO
Is a response characteristic in a state where compensation is performed by the minimum compensation component signal ΔVCS generated from the minimum time constant CR,
It can be considered that the compensation is hardly performed. Then, the MPU 84 uses the actual pressure signal VO stored in the RAM 86.
The rate of change of the actual pressure signal VO (hereinafter referred to as pressure gradient) is calculated from the data of (S5). Therefore, the calculated pressure gradient has a value corresponding to the capacity of the connected load L.

Next, the MPU 84 selects two rate of change, the magnitude of which is closest to the calculated pressure gradient, from the correction amount data stored in the ROM 85 (S6). And MPU84
Calculates the time constant CR corresponding to the calculated pressure gradient from each time constant CR corresponding to both change rates. (S7). This calculation method is calculated from the relationship with the time constant that requires a change in the load L. For example, the ratio of the pressure gradient to both rate of change is calculated from the time constant CR corresponding to both rate of change to the time constant to the pressure gradient. Calculate CR. This time constant CR is a value that enables optimum pressure control for this load L. Next, the MPU 84 outputs a time constant setting signal corresponding to the calculated time constant CR to the differentiating circuit 46 (S
8). As a result, the time constant CR of the differentiating circuit 46 is set to the time constant CR corresponding to the time constant setting signal.

Upon completion of the above time constant setting processing, the MPU 84 switches the changeover switch 82 to the terminal side to which the target pressure signal VS is input (S9). Then, the input of the test pressure signal VI is stopped and the signal input to the subtractor 41 becomes 0, so that the deviation signal ΔV becomes negative. Therefore, the deviation signal .DELTA.V controls the exhaust electromagnetic valve 31 to open, and the pilot pressure PP is exhausted, so that the air is exhausted from the outflow port 5 side and the target pressure Po becomes zero. This completes the time constant setting process.

Now, the pressure proportional control valve 1 in which the optimum time constant CR is set according to the capacity of the load L thus connected is set.
A target pressure signal VS corresponding to a predetermined target pressure PS is input to the external device 40a. Then, the air supply solenoid valve 30 is controlled to open at the duty ratio based on the deviation signal ΔV between the target pressure signal VS and the compensation pressure signal VC. As a result, air is introduced into the pilot chamber 26, the pilot pressure PP rises, and a downward operating force acts on the diaphragm 27, so that air is introduced from the inflow port 4 to the outflow port 5.

When air is introduced into the outflow port 5, the target pressure PO and the feedback pressure PF increase at an increasing rate according to the capacity of the load L. When the actual pressure signal VO of this increase rate is input to the differentiating circuit 46, the compensation signal ΔV obtained by multiplying the differentiating signal by the time constant CR set by the microcomputer 81.
CS is generated and output to the adder 45. Then, the deviation signal ΔV is generated by the compensation pressure signal VC obtained by adding the compensation component signal ΔVCS obtained to the actual pressure signal VO.

The time constant CR is set to the minimum value in accordance with the capacity of the load L as long as the pilot pressure PP is controlled to the target pressure PS when the target pressure PO first reaches the target pressure PS. . As a result, when the air supply solenoid valve 30 or the exhaust solenoid valve 31 is controlled to be opened by the deviation signal ΔV compensated by the minimum compensation component signal ΔVCS, the pilot pressure PP is rapidly controlled to the target pressure PS. Therefore, this pilot pressure PP causes the target pressure PO to reach the target pressure P
Controlled by S at high speed.

Further, the compensation component signal ΔVCS is the actual pressure signal VO
Since it is generated by the product of the differential signal of and the time constant CR,
At the time when the target pressure P0 reaches the target pressure Ps, the deviation signal .DELTA.V becomes zero. As a result, since the pilot pressure PP is controlled to the target pressure PS with high accuracy, the target pressure PO is controlled to the target pressure PS with high accuracy.

When performing pressure control of the load L having different capacity, after connecting the load L to the pressure proportional control valve 1, the test command signal S is sent from the external device 40b to the microcomputer 81 again.
Enter C. Then, the microcomputer unit 81 executes the time constant setting process again. As a result, the time constant CR of the differentiating circuit 46 is set to the time constant CR according to the capacity of the load L, so that the pressure control of the newly connected load L can be performed at high speed and with high accuracy. Become.

According to the pressure proportional control valve described in detail above, the following effects can be obtained. (A) When a load L having a certain capacity is connected, first, the microcomputer unit 81 performs a time constant setting process for determining a time constant CR capable of performing optimum pressure control for the load L. That is, the preset test pressure signal VI is input with the time constant CR of the differentiating circuit 46 set to the minimum, and the actual pressure signal VO corresponding to this test pressure signal VI is obtained. Then, the pressure gradient of this actual pressure signal VO is calculated,
From this pressure gradient, the optimum time constant CR for the capacity of the load L is determined and set as the time constant CR of the differentiating circuit 46. Note that the microcomputer unit 81 is provided with correction amount data corresponding to a time constant CR capable of optimally compensating for a different rate of change (that is, a pressure gradient with respect to the load L having a different capacity) in advance through experiments or the like. ing. Then, in the time constant setting process, the time constant CR corresponding to the calculated pressure gradient is calculated from the correction amount data. Therefore, the pressure control of each load L can be performed at high speed and with high accuracy only by causing the microcomputer unit 81 to perform the differential constant setting process for the load L of various capacities before performing the pressure control.

(B) In the present embodiment, unlike the first embodiment, since the time constant CR corresponding to the capacity of the load L is set only once at the beginning, an existing microcomputer having a slow processing speed is used. Then, the microcomputer unit 81 can be configured.
Therefore, the time constant setting circuit 47 in the first embodiment is
Since it is cheaper than the above, the pressure proportional control valve 1 can be provided at low cost. The pressure proportional control valve 1 of the present embodiment can be used when the capacity of the connected load L does not change during use.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. In this embodiment, in the first embodiment, the controller 37 is changed to a controller 90 having a different internal structure, and a pressure sensor 91 for detecting the pilot pressure PP of the pilot chamber 26 is provided. Only that point is different from the first embodiment. Therefore, only the configuration of the control unit 90 and the pressure sensor 91 will be described in detail, and the same configurations as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 9, the pressure sensor 91 has a third
The pilot pressure PP is applied to the housing 25 through the flow path from the pilot chamber 26. The pressure sensor 91 outputs a pilot pressure detection signal VPP corresponding to the pressure in the pilot chamber 26 to the control unit 90. In the present embodiment, the first pressure sensor in the pressure sensor 38 is
The pressure sensor 91 constitutes a second pressure sensor.

Next, the structure of the control unit 90 will be described. FIG.
As shown in, the control unit 90 controls the subtracters 92, 93, 9
4, amplifiers 95, 96, 97, 98 and PMW circuit unit 4
And 3. In the present embodiment, the subtractor 9
The second subtraction unit is configured by 2 and the second subtraction unit is configured by the subtractor 93. Also, the subtractor 94 and the amplifier 9
An operating force signal generation unit is constituted by 7,98. Further, the PMW control section 43 and the amplifier 96 constitute a pilot pressure control means.

The subtractor 92 receives the target pressure signal VS corresponding to the target pressure PS from the external device 40a. Further, the subtractor 92 inputs the actual pressure signal VO from the pressure sensor 38. The subtractor 92 subtracts the actual pressure signal VO from the target pressure signal VS and calculates the difference between them by the first deviation signal .DELTA.V1 (= VS-.
VO) to the amplifier 95. Therefore, the first deviation signal .DELTA.V1 is a pressure deviation between the target pressure PS and the actual pressure PO, and is a necessary (target) manipulated variable.

The amplifier 95 amplifies the first deviation signal ΔV1 and uses the amplified signal as a correction deviation signal ΔVH to the subtractor 9
Output to 3. Here, the correction deviation signal ΔVH is used as a target signal of the manipulated variable for bringing the pressure deviation close to zero.

The subtractor 93 inputs an operation force signal VF described later from the amplifier 98. Then, the subtractor 93 subtracts the operating force signal VF from the correction deviation signal ΔVH, and the difference is used as a second deviation signal ΔV2 (= ΔVH-VF) to amplify the amplifier 9.
6 is output. That is, the second deviation signal ΔV2 becomes a deviation signal of the operating force. The amplifier 96 uses the second deviation signal ΔV.
Amplifies H and outputs the amplified signal to the PWM circuit unit 43 as a control deviation signal ΔVCR.

The PWM circuit section 43 controls the control deviation signal ΔVCR.
On the other hand, the control drive signal VD composed of a pulse train having a duty ratio uniquely determined is output to the air supply solenoid valve 30 or the exhaust solenoid valve 31. That is, when the control deviation signal .DELTA.VCR is positive, the control drive signal VD is output to the air supply solenoid valve 30. When the control drive signal ΔVCR is negative, the control drive signal VD is output to the exhaust solenoid valve 31.

On the other hand, the amplifier 97 receives the pilot pressure detection signal VPP from the pressure sensor 91. The amplifier 97 amplifies the pilot pressure detection signal VPP with an amplification factor equal to the ratio of the pressure receiving area on the feedback chamber 23 side of the diaphragm 27 to the pressure receiving area on the pilot chamber 26 side, and the correction pressure signal V
It is output to the subtractor 94 as a PC. The corrected pressure signal VPC is
It is the amount of pilot pressure PP converted to feedback pressure PF. That is, the corrected pressure signal VPC is the diaphragm 2
This corresponds to the force of operating 7 downward. This is because the operating force of the diaphragm 27 is a value obtained by multiplying the pilot pressure PP by the pressure-receiving area of the diaphragm 27 on the pilot chamber 26 side, and the pilot pressure PO of the feedback chamber 23 is the feedback pressure of the diaphragm 27.
When the pressure receiving area on the pilot chamber 26 side of the diaphragm 27 and the pressure receiving area on the feedback chamber 23 side are different, the pressure is generated by the opposing relationship with the upward operating force, which is a value obtained by multiplying the pressure receiving area on the side of the pressure chamber. This is because it is necessary to convert the pilot pressure PP into the feedback pressure PF in order to compare the forces. In the present embodiment, since the pressure receiving area of the diaphragm 27 on the pilot chamber 26 side and the pressure receiving area of the feedback chamber 23 on the diaphragm 27 are the same, the amplification factor is 1.

The subtractor 94 receives the actual pressure signal VO from the pressure sensor 38. Here, the actual pressure signal VO corresponds to the force that operates the diaphragm 27 upward. The subtractor 94 uses the correction pressure signal VPC corresponding to the downward operation force.
Subtract the actual pressure signal VO corresponding to the upward operating force from
An amplifier 98 as a pressure deviation signal .DELTA.V3 (= VPC-VO).
Output to Therefore, the pressure deviation signal .DELTA.V3 has a value corresponding to the operating force actually applied to the diaphragm 27.

The amplifier 98 amplifies the pressure deviation signal ΔV3 and outputs this signal to the subtractor 93 as an operating force signal VF. Therefore, the operation force signal VF has a value corresponding to the downward operation force that actually acts on the diaphragm 27.

Therefore, the second deviation signal ΔV2 obtained by subtracting the operation force signal VF from the first deviation signal ΔV1 corresponds to the insufficient operation force (that is, the operation force deviation) required to obtain the target pressure PS. Signal to do. Further, the amplification factors of the amplifier 95 and the amplifier 98 are determined from the relationship of the operating force required for the pressure deviation.

Next, the operation of the pressure proportional control valve 1 configured as above will be described with reference to FIG. When the target pressure signal VS in the subtractor 92 is input after the load L is connected, the first deviation signal ΔV1 which is the target operation amount becomes maximum and the operation force signal VF is 0. The second deviation signal .DELTA.V2, which is the deviation signal, becomes maximum. As a result,
Since the air supply solenoid valve 30 is controlled to open at the maximum duty ratio so that the operating force is maximized, the pilot pressure PP increases and a downward operating force is generated due to the pressure difference from the feedback pressure PF. Since the diaphragm 27 is driven downward by this operating force, air is introduced from the inflow port 4 into the outflow port 5 and the actual pressure P0 rises. At the same time, since the feedback pressure PF rises, the actual pressure signal VO which gradually rises from 0 according to the capacity of the load L is input to the subtractors 92 and 94. Therefore, since the actual pressure P0 approaches the target pressure Ps, the magnitude of the first deviation signal .DELTA.V1 gradually decreases.

The second deviation signal ΔV2 is the pilot pressure P
As P increases, the downward operating force increases, approaches the target pressure PS, and approaches zero. That is, the first deviation signal .DELTA.V1 and the operation force signal VF are controlled so as to coincide with each other. The actual pressure P0 rises and approaches the target pressure Ps.
When the deviation signal .DELTA.V1 becomes smaller, the target operating force becomes smaller. Therefore, the air supply solenoid valve 30 is designed to reduce the operating force.
The average opening time is shortened and the increase rate of the pilot pressure PP decreases. Then, the operating force signal VF that has once risen decreases.

Then, when the actual pressure P0 reaches the target pressure Ps, the operating force becomes 0 and the operation of the air supply solenoid valve 30 is stopped. As a result, the actual pressure P0 is accurately controlled to the target pressure Ps.

Further, the second deviation signal .DELTA.V2 obtained by subtracting the operating force signal VF from the first deviation signal .DELTA.V1 is controlled to be zero. That is, the average opening time of both solenoid valves 30, 31 is controlled so that the pilot pressure PP is such that the operating force matches the first deviation signal .DELTA.V1. Therefore,
The operating force has a characteristic that it is large in the initial stage of control and becomes smaller in the latter stage of control. As a result, at the initial stage of control, the average opening time of the solenoid valve 30 for air supply becomes longer, so that the pilot pressure P
P rapidly increases toward the target pressure PS. And
In the latter half of the control, the average opening time of the air supply solenoid valve 30 becomes shorter, so the pilot pressure PP is controlled to the target pressure PS with high accuracy. Therefore, the actual pressure P0 is controlled to the target pressure Ps at high speed and with high accuracy. When the first deviation amount .DELTA.V1 is 0, the operating force becomes 0, so that the actual pressure P.sub.0 is controlled to the target pressure P.sub.S at high speed and with high accuracy regardless of the capacity of the load L.

According to the pressure proportional control valve of the present embodiment detailed above, the following effects can be obtained. (A) The actual pressure P0 is detected and the target pressure PS and the actual pressure P are detected.
The first deviation signal .DELTA.V1 which is the difference from O is obtained, and the pilot pressure PP is detected to obtain the operating force signal VF. Then, from the first deviation signal ΔV1 to the operation force signal VF
To obtain the second deviation signal .DELTA.V2, and the air supply solenoid valve 30 or the exhaust solenoid valve 31 is controlled to open based on the second deviation signal .DELTA.V2. As a result, the actual pressure Po
Is controlled to the target pressure PS, and the pilot pressure PP is adjusted so that the operating force becomes 0 when the target pressure PS is reached.
Is controlled. Further, since the operating force in which the first deviation signal .DELTA.V1 and the operating force signal VF coincide with each other is obtained, the operating force becomes large in the initial stage of control and becomes smaller in the latter stage of control. Therefore, the air supply solenoid valve 30 can be driven with a longer average opening time in the initial period of control, and the air supply solenoid valve 30 or the exhaust electromagnetic valve 31 can be driven with a shorter average opening time in the latter period of control. As a result, it is possible to control the actual pressure P0 to the target pressure Ps at high speed and with high accuracy without performing adjustment work or the like according to the capacity of the load L.

(B) Since the air supply solenoid valve 30 and the exhaust solenoid valve 31 are switched to perform the open control, air consumption associated with the control can be minimized. (C) Since the operation of each solenoid valve 30, 31 can be minimized, the life of each solenoid valve 30, 31 can be extended.

(D) Since expensive parts such as a highly accurate orifice are not used, the cost can be reduced.
The present invention is not limited to the above-mentioned embodiments, but may be configured as follows.

Further, the pressure proportional control valve of this embodiment can also be constructed as follows. (1) In the first embodiment, the differential constant setting unit 4
7 may be omitted, and the time constant CR of the differentiating circuit 46 may be fixed to the time constant CR corresponding to only the load L of a specific capacity. That is, from the outside of the pressure proportional control valve 1, the resistor 50 of the differentiating circuit 46 or the capacitor 65 itself, or
The pressure proportional control valve 1 corresponding to only the capacity of the load L to be used may be set by configuring either of the values to be changeable. With this configuration, the pressure proportional control valve 1 can be provided at low cost.

(2) In the second embodiment, the microcomputer section 81 is provided outside the pressure proportional control valve 1, and the pressure proportional control valve 1 is provided only when the time constant CR of the differentiating circuit 46 is set at the start of use. You may make it connect. further,
The microcomputer 81 may be incorporated in the external device 40a for inputting the target pressure signal VS corresponding to the target pressure PS to the proportional control valve 1.

(3) In the second embodiment, a microcomputer capable of high-speed processing is used as the microcomputer unit 81, the pressure gradient of the input actual pressure signal VO is sequentially calculated, and the differentiation circuit unit is based on this pressure gradient. The time constant CR of 46 may be sequentially set. According to this configuration, since the optimum time constant CR is sequentially set with respect to the input actual pressure signal VO, high-speed and highly accurate pressure control can be performed even when the capacity of the load L changes during use. It can be carried out.

Further, in the second embodiment, the microcomputer 81 is composed of a microcomputer capable of high-speed processing, and the microcomputer operates a drive circuit for driving the solenoid valves 30 and 31 based on the deviation signal ΔV. The control operation signal may be generated. According to this configuration, the carrier triangular wave generation circuit, the comparator, and the like that configure the PWM circuit unit 43 can be eliminated, and thus the control unit 3
7 can be downsized.

(4) In each of the above embodiments, as the pilot pressure adjusting means, the 2-position 2-port air supply solenoid valve 3 is used.
0 and a solenoid valve 31 for exhaust were used. As shown in FIG. 12, these were replaced by an orifice 100 and a nozzle flapper mechanism 101.
Alternatively, the pilot pressure PP may be controlled by constantly supplying air to the pilot chamber and controlling the drive of the nozzle flapper mechanism 101 by the drive circuit 102. In this case, the nozzle flapper mechanism 10
1 may be duty controlled by a pulse drive signal,
Alternatively, the switching control may be simply performed.

Further, the pilot pressure PP may be controlled by the switching control of the single 2-position 3-port solenoid valve 103 shown in FIG. In this example, the control deviation signal ΔV of the above-described embodiment is input to the comparator 104 to determine whether it is positive or negative, an on / off drive signal is generated based on the determined signal, and this drive signal is output to the drive circuit 105. By doing so, the solenoid valve 103 is controlled to be switched to two positions.

(5) In the first and second embodiments, the electronic volume 50a may be replaced with a variable resistance multiplier. Further, the electronic constant 50a may be replaced with a fixed resistance, and the time constant CR may be changed by changing the capacitance of the capacitor 65. At that time, the capacitor 65 may be a variable capacitance multiplier.

(6) In each embodiment, the differentiation circuit 46
The differential signal corresponding to the change rate of the actual pressure signal VO is obtained. Instead of the differentiating circuit 46, a high-speed microcomputer may be used to calculate the rate of change of the actual pressure signal VO. In this case, this microcomputer sets a correction amount capable of performing optimum compensation based on the change amount of the actual pressure signal VO from the stored correction amount data. Then, the data corresponding to the compensation component signal .DELTA.VCS is obtained from the product of the set correction amount and the change rate of the actual pressure signal VO, and the compensation component signal .DELTA.CS is generated based on this data.

(7) As the differentiating circuit 46, a circuit having an operational amplifier 64 is used. However, this is composed of another differentiating circuit, for example, a differentiating circuit in which a capacitor and a resistor are connected in series, or a coil. Alternatively, a differentiating circuit or a differentiating circuit including a capacitor may be used. In this case, the time constant is CR in the differentiation circuit composed of the capacitor and the resistor. In the differentiating circuit including the coil, the time constant is L (inductance). Further, in the differentiating circuit composed of a capacitor, the time is C (capacitance). Therefore,
In each case, the compensation component signal ΔVCS can be directly obtained by setting each time constant as the correction amount.

(8) Instead of directly taking out the compensation component signal ΔVCS from the differentiating circuit 46, by connecting a multiplier to the output side of the differentiating circuit 46 and changing the gain of this multiplier according to the capacity of the load, The output of the multiplier is the compensation component signal ΔV
It may be configured to be CS. That is, in this case, the differentiating circuit 46 and the multiplier constitute the compensation component signal generating means, and the multiplier constitutes the correction amount changing means.

(9) In the first, second, and third embodiments, the open control of the air supply solenoid valve 30 and the exhaust solenoid valve 31 is not performed by duty control using a pulse signal but turned on.
It may be a simple switching control by an off signal.

The technical ideas other than the claims that can be understood from the above-described embodiments will be described below along with their effects. (1) In the pressure proportional control valve according to the fifth and eighth aspects, the pilot pressure adjusting means is duty-controlled by a pulse train signal. With this configuration, the pilot pressure can be controlled with high accuracy without using a component such as a nozzle flapper mechanism that requires high dimensional accuracy. (2) In the pressure proportional control valve according to claim 5, the compensating means differentiates the actual pressure signal VO to generate a differential signal, and the differential signal is multiplied by a correction amount inputted from the outside. It is composed of differentiating means for generating ΔVCS. According to this configuration, it is not necessary to provide the microcomputer unit 81 or the like for setting the correction amount in the pressure proportional control valve 1 main body, and only when the correction amount is set for a certain load L, the microcomputer unit 81 or the like is provided. Since the optimum correction amount can be set for the capacity of the load L by connecting to the differentiating means, the structure of the pressure proportional control valve can be simplified and provided at low cost.

[0116]

As described in detail above, claims 1, 2, and
According to the inventions described in 4, 5, and 8, pressure control can be performed at high speed and with high accuracy even for loads having different capacities without requiring specialized knowledge or adjustment work requiring a great amount of work time.

According to the invention described in claims 3 and 6,
In addition to the effect of the invention described in claim 1, it is possible to automatically obtain a compensation component signal capable of performing optimum pressure control according to the capacity of the load. Therefore, the adjustment work according to the load capacity performed by the user can be completely abolished.

According to the invention described in claim 6, in addition to the effect of the invention described in claim 5, since the differential circuit can obtain the differential signal corresponding to the rate of change of the actual pressure signal, The compensating means can be easily constructed.

According to the invention described in claim 7, in addition to the effect of the invention described in claim 5, it is possible to easily obtain a compensation component signal capable of performing optimum pressure control according to the capacity of the load. Since it can be set, pressure control of loads of various capacities can be easily performed. Moreover, since the compensating means can be easily configured by an existing microcomputer, the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a pressure control device for a pressure control valve according to a first embodiment.

FIG. 2 is a block diagram showing a configuration of a compensation unit.

FIG. 3 is a circuit diagram of a compensation unit.

FIG. 4 is a sectional view of a pressure proportional control valve.

FIG. 5 is a graph showing step response characteristics.

FIG. 6 is a block diagram of a pressure proportional control valve according to a second embodiment.

FIG. 7 is a flowchart of a control program for the microcomputer unit.

FIG. 8 is a block diagram of a pressure proportional control valve according to a third embodiment.

FIG. 9 is a sectional view of a pressure proportional control valve.

FIG. 10 is a step response characteristic diagram of each signal and actual pressure.

FIG. 11 is a block diagram of another example of pilot pressure adjusting means.

FIG. 12 is a similar configuration diagram.

FIG. 13 is a cross-sectional view of a conventional pressure proportional control valve.

FIG. 14 is a sectional view of the same.

FIG. 15 is a sectional view of the same.

[Explanation of symbols]

11 ... Valve body constituting main valve, 18 ... Valve body, 20 ...
Similarly, rod, 30 ... solenoid valve for air supply as pilot pressure adjusting means, 31 ... solenoid valve for exhausting, 38 ... first pressure sensor, 41 ... subtractor as subtracting section, 43 ... control means and pilot pressure control PMW circuit section as means,
44 ... Compensation section as compensation means, 45 ... Adder as addition section, 46 ... Differentiation circuit, 47 ... Time constant setting circuit as correction amount setting means, 81 ... Microcomputer section, 84 ... MPU as correction amount setting means , 85 ... ROM as a storage unit,
91 ... 2nd pressure sensor, 92 ... 1st subtraction part, 93 ...
2nd subtraction part, 94 ... Subtractor which comprises an operation force signal generation part, 97 ... Amplifier which comprises an operation force signal generation part, 98 ...
Similarly, amplifier, 120 ... Main valve, PF ... Feedback pressure, PO ... Actual pressure, PP ... Pilot pressure, PS ... Target pressure, VC ... Compensation pressure signal, VF ... Operating force signal, VO ... Actual pressure signal, VPP ... Pilot pressure Detection signal, VS ... Target pressure signal, ΔV ... Deviation signal, ΔV1 ... First deviation signal, Δ
V2 ... Second deviation signal, .DELTA.VCS ... Compensation component signal.

Claims (8)

[Claims] 1. A pilot pressure (PP) for operating a main valve (120) for controlling an actual pressure (PO) supplied to a load (L) by opposition to a feedback pressure (PF) of the actual pressure (PO). Is controlled so as to reduce the deviation (ΔVO) between the target pressure signal (VS) corresponding to the target pressure (PS) and the actual pressure signal (VO) which is the detected value of the actual pressure (PO). In the pressure control method of the pressure proportional control valve in which (PO) is controlled to the target pressure (PS), the pilot pressure (PP) is the target when the actual pressure (PO) is controlled to the target pressure (PS). A pressure control method in a pressure proportional control valve adapted to compensate an actual pressure signal (VO) so as to be controlled to a pressure balanced with a feedback pressure (PF) with respect to the pressure (PS). 2. A pilot pressure (PP) for operating a main valve (120) for controlling an actual pressure (PO) supplied to a load (L) by opposition to a feedback pressure (PF) of the actual pressure (PO). Is controlled so as to reduce the deviation (ΔVO) between the target pressure signal (VS) corresponding to the target pressure (PS) and the actual pressure signal (VO) which is the detected value of the actual pressure (PO). In a pressure control method in a pressure proportional control valve in which (PO) is controlled to a target pressure (PS), a preset value is set according to the rate of change of the actual pressure signal (VO) and the capacity of the load (L). A compensation component signal (ΔVCS) proportional to the product of the correction amount (CR) is generated, and this compensation component signal (ΔVCS) is generated.
VCS) is added to the actual pressure signal (PO) to generate a compensation pressure signal (VC), and the pilot pressure (PP) is controlled based on the deviation between the target pressure signal (VS) and the compensation pressure signal (VC). Pressure control method for pressure proportional control valve. 3. Based on the rate of change of the actual pressure signal (VO),
The pressure control method for a pressure proportional control valve according to claim 2, wherein the correction amount (CR) is changed according to the capacity of the load (L). 4. A pilot pressure (PP) for operating a main valve (120) for controlling an actual pressure (PO) supplied to a load (L) by opposition to a feedback pressure (PF) of the actual pressure (PO). Is controlled so as to reduce the deviation (ΔVO) between the target pressure signal (VS) corresponding to the target pressure (PS) and the actual pressure signal (VO) which is the detected value of the actual pressure (PO). In a pressure control method in a pressure proportional control valve in which (PO) is controlled to a target pressure (PS), a first deviation signal (deviation between the target pressure signal (VS) and the actual pressure signal (V) is given. .DELTA.V1) and an operating force signal (VF) corresponding to the operating force is obtained from the pilot pressure detection signal (VPP) which is the detected value of the pilot pressure (PP) and the actual pressure signal (VO). Deviation signal (ΔV1) and operating force signal (VF 2) which is the deviation from
Of the second deviation signal (ΔV2)
A pressure control method in a pressure proportional control valve in which the pilot pressure (PP) is controlled so as to reduce V2). 5. The actual pressure (P O) is detected and the actual pressure (P O) is detected.
Pressure sensor (38) for outputting an actual pressure signal (VO) corresponding to O), pilot pressure adjusting means (30, 31) for adjusting pilot pressure (PP), and target pressure corresponding to target pressure (PS) Signal (VS),
The actual pressure signal (VO) is input and the target pressure signal (VS
) And the actual pressure signal (VO), a subtraction section (41) for obtaining a deviation signal (ΔV), and a control means for controlling the pilot pressure adjusting means (30, 31) so that the deviation signal (ΔV) becomes smaller (4
3) In the pressure proportional control valve, the compensation is proportional to the product of the rate of change of the actual pressure signal (VO) and a correction amount (CR) preset according to the capacity of the load (L). Compensation means (4) that outputs the minute signal (ΔVCS)
4) and the compensation component signal (ΔVCS) is added to the pressure detection signal (VO) to generate a compensation pressure signal (VC), and the compensation pressure signal (VC) is output to the subtraction unit (41). Division (4
5), wherein the subtraction unit (41) subtracts the compensation pressure signal (VC) from the target pressure signal (VS) to obtain the deviation signal (ΔV). 6. A differentiating circuit (46) for differentiating the actual pressure signal (VO) and outputting a differential signal proportional to the rate of change thereof, and a differentiating means for outputting the differential signal (46). Correction amount (C
The compensation amount signal generating means (46) for generating the compensation amount signal (ΔVCS) multiplied by R) and the correction amount (C) based on the change rate of the actual pressure signal (VO).
The pressure proportional control valve according to claim 5, further comprising a correction amount changing means (47) for changing R) to a value set in advance according to the capacity of the load (L). 7. The compensating means (44) differentiates the actual pressure signal (VO) and outputs a differential signal proportional to the rate of change thereof, and a differential signal output by the differentiating means, Compensation component signal (ΔVCS) multiplied by a correction amount that is preset according to the capacity of the load
And a microcomputer unit (81) for generating a plurality of actual pressure signals (VO
), And a storage unit (85) for storing correction amount data including a correction amount set in advance for each change ratio,
Correction amount setting means (84) for obtaining a change rate of the actual pressure signal (VO) obtained with respect to the test pressure signal (VI) input in advance and obtaining a correction amount corresponding to the obtained change rate from the correction amount data. And the pressure proportional control valve according to claim 5. 8. Pilot pressure (PP) and actual pressure (PO)
The main valve (120) which is driven by the operating force generated by the facing relationship of (1) and controls the actual pressure (PO) and the actual pressure (PO) are detected and the actual pressure signal corresponding to the actual pressure (PO) The first pressure sensor (3
8) and pilot pressure adjusting means (30, 31) for adjusting the pilot pressure (PP), based on the target pressure signal (VS) and the actual pressure signal (VO) corresponding to the target pressure (PS). In a pressure proportional control valve for driving the pilot pressure adjusting means (30, 31) to control the pilot pressure (PP) and operating the main valve (120) to control the actual pressure (PO) to the target pressure (PS). , The pilot pressure (PP) is detected and the pilot pressure (PP
), A second pressure sensor (91) that outputs a pilot pressure detection signal (VPP), and an operating force that acts on the main valve (120) from the actual pressure signal (VO) and the pilot pressure detection signal (VPP). An operation force signal generator (94, 9) for generating an operation force signal (VF) corresponding to
7, 98), and a first subtraction unit (92) for generating a first deviation signal (ΔV1) between the target pressure signal (VS) and the actual pressure signal (VO).
And a second subtraction unit (9) for generating a second deviation signal (ΔV2) between the first deviation signal (ΔV1) and the operating force signal (VF).
3) and a pilot pressure control means (43) for controlling the pilot pressure adjusting means (30, 31) based on the second deviation signal (ΔV2).