JP2002023858A - Pilot type pressure proportional control valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pilot type pressure proportional control valve system for quietly and precisely controlling supply pressure with high responsiveness. SOLUTION: A pilot type pressure proportional control valve 10 is provided with a first diaphragm chamber 16 and a second diaphragm chamber 17 separated by a pilot valve 14 constituted as a diaphragm structure, and the second diaphragm chamber 17 is communicated with an output port 12. Also, this pilot type pressure proportional control valve 10 is provided with an electromagnetic valve 25 for supply arranged between the first diaphragm chamber 16 and a supply air source, an orifice 26 arranged between the first diaphragm chamber 16 and an exhaust pipe, and a pressure gauge 29 for measuring the pressure of the output port 12. An electromagnetic valve 25 for supply of the pilot type pressure proportional control valve 10 is controlled, and the pressure of the first diaphragm chamber 16 is made correspond to the measured value of the pressure gauge 29 so that the position of a main valve can be controlled, and that the pressure of the output port 12 can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot type pressure proportional control valve system for controlling the pressure of a fluid flowing through a main valve by controlling an opening degree of a main valve by controlling an air pressure supplied to the pilot valve. Things.

[0002]

2. Description of the Related Art Conventionally, a pilot type pressure proportional control valve has been used. FIGS. 10A and 10B show the structure.
Shown in (A) is AA sectional drawing of (b). The pilot pressure proportional control valve 100 has a supply port 101, an exhaust port 102, and an output port 103 formed in a body. The pilot valve 105 has a diaphragm structure, and includes a first diaphragm chamber 106 and a second diaphragm chamber 107 isolated by the pilot valve 105. Further, a supply solenoid valve (not shown) for supplying air pressure to the first diaphragm chamber 106 is attached. Further, the second diaphragm chamber 107 and the output port 103 of the main valve are communicated by the communication passage 104. Thereby, the output pressure of the main valve to be controlled is applied to the second diaphragm chamber 107.

A first valve seat 111 and a second valve seat 112 are formed on the body. A first valve body 109 that comes into contact with or separates from the first valve seat 111 is slidably held. In addition, the second valve seat abuts or separates from the second valve seat 112.
The valve body 110 is slidably held. First valve body 10
9 is the first return spring 1 in the direction in which it comes into contact with the first valve seat 111.
13. In addition, the second valve body 110
It is urged by a second return spring 114 in a direction in which it comes into contact with the second valve seat 112.

Next, the pilot type pressure proportional control valve 1
The operation of 00 will be described. A control device (not shown) supplies air at a predetermined pressure, which is a pilot pressure, to the first diaphragm chamber 106 from a supply solenoid valve. When the pressure in the first diaphragm chamber 106 and the pressure in the second diaphragm chamber 107 are equal and the pilot valve 105 is in the neutral position as shown in FIG.
The output port 103 is not in communication with the supply port 101 or the exhaust port 102 because the second valve body 110 is in contact with the second valve seat 112.

[0005] The output port 10 is controlled by the pilot pressure.
3, the pilot valve 105 moves downward, and the pilot valve shaft 108 moves the second valve body 110
Supply port 101 and output port 10
3 and the supply air flows to the output port 103. When the pressure of the output port 103 rises,
Since the pilot valve 105 moves upward and the pilot valve shaft 108 pushes up the first valve body 109, the output port 102 and the output port 103 communicate with each other, and the output air flows to the exhaust port 102. This allows a fluid at a predetermined pressure to flow from the output port 103.

However, it is difficult to control the air pressure supplied to the first diaphragm chamber 106 to a desired pressure accurately and with high responsiveness using only one supply solenoid valve. On the other hand, as a supply electromagnetic valve, a method of controlling supply pressure with high accuracy and high responsiveness by using two pulse-type electromagnetic valves is known. For example, in Japanese Patent Application Laid-Open No. 9-72458, a first pilot valve is provided for a vacuum pressure control valve.
A first supply electromagnetic valve provided between the diaphragm chamber and the supply air source, and a first exhaust electromagnetic valve provided between the first diaphragm chamber and the exhaust pipe; A pilot pressure proportional control valve system is disclosed that controls the position of a diaphragm valve by controlling a valve and a first exhaust solenoid valve, and controls the pressure of fluid flowing through a main valve.

[0007]

However, the conventional pilot pressure proportional control valve system has the following problems. That is, when a pulse-type supply solenoid valve and a pulse-type exhaust solenoid valve are used to control the air pressure supplied to the first diaphragm chamber, the beating noise of the exhaust solenoid valve using fluid as a medium is obtained. It was transmitted to the exhaust duct, etc., and sometimes caused a problem as noise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a pilot type pressure proportional control valve system which controls a supply pressure quietly, accurately and with high responsiveness. I do.

[0009]

In order to solve the above problems, a pilot type pressure proportional control valve system according to the present invention is provided.
By controlling the air pressure supplied to the pilot valve,
In a pilot pressure proportional control valve system for controlling a pressure of a fluid flowing through a main valve by controlling an opening degree of a main valve, a pilot valve has a diaphragm structure, a first diaphragm chamber isolated by a diaphragm, and a second diaphragm. A second diaphragm chamber is communicated with an output port of the main valve, and a supply solenoid valve provided between the first diaphragm chamber and a supply air source, and a second solenoid valve is provided between the first diaphragm chamber and the exhaust pipe. And a pressure gauge for measuring the pressure of the output port.
The position of the main valve is controlled by making the pressure in the diaphragm chamber correspond to the value measured by the pressure gauge.

According to the configuration of the present invention, since the exhaust solenoid valve conventionally provided is not used, no noise is generated by the exhaust solenoid valve. By providing an orifice in the first diaphragm chamber in place of the exhaust solenoid valve, a constant amount of exhaust is constantly performed, and the supply air pressure is controlled by the supply solenoid valve. If the opening degree of the supply solenoid valve is made larger than the communication amount of the orifice, the pressure in the first diaphragm chamber rises. If the opening degree of the supply solenoid valve is made smaller than the communication amount of the orifice, the pressure in the first diaphragm chamber is increased. Drops. Therefore, by controlling the opening of the supply solenoid valve, the pressure in the first diaphragm chamber is controlled to the pilot pressure. Here, by using a pulse-type solenoid valve as the supply solenoid valve, control with higher responsiveness and higher responsiveness is performed.

On the other hand, since the second diaphragm chamber communicates with the output port of the main valve, if the pressure of the output port decreases or increases, the pressure of the second diaphragm chamber also decreases or increases. Then, the balance with the first diaphragm chamber is lost, the opening of the main valve is controlled, and the pressure of the second diaphragm chamber and the output port is controlled to the pilot pressure. Further, the output port of the main valve communicates with the second diaphragm chamber, and the pressure is measured by a pressure gauge. Therefore, feedforward control is possible by predicting a pressure change corresponding to the measurement value of the pressure gauge and controlling the supply solenoid valve.

However, in the pilot-type pressure proportional control valve having this configuration, exhaust is performed only through the orifice. Although the displacement of the orifice is almost constant, a certain degree of error occurs due to variations in the production and the environment in use. Therefore, even if the opening of the supply solenoid valve is controlled in accordance with the measurement value of the pressure gauge, a slight error may occur. Since the error appears again in the measured value of the pressure gauge, it can be corrected by further controlling the opening of the supply solenoid valve, but there is a problem in accuracy and responsiveness.

In order to solve the above-mentioned problems, a pilot type pressure proportional control valve system according to the present invention controls an air pressure supplied to a pilot valve, thereby controlling an opening degree of a main valve to control a fluid flowing through the main valve. In a pilot-type pressure proportional control valve system in which two pilot-type pressure proportional control valves for controlling pressure are integrally formed by sharing an output port of each main valve, an input port of a first main valve communicates with a supply air source. The input port of the second main valve is communicated with the exhaust pipe,
The pilot valves each have a diaphragm structure, and the first
The first diaphragm isolated by the first diaphragm of the pilot valve
A diaphragm chamber, a second diaphragm chamber, a third diaphragm chamber and a fourth diaphragm chamber separated by a second diaphragm of a second pilot valve, wherein the first diaphragm chamber and the third diaphragm chamber are communicated with an exhaust pipe; , Second
A first supply solenoid valve provided between the diaphragm chamber and the supply air source, a first orifice provided between the second diaphragm chamber and the exhaust pipe, and a fourth supply port between the fourth diaphragm chamber and the supply air source. A second supply solenoid valve provided therebetween, a second orifice provided between the fourth diaphragm chamber and the exhaust pipe, and a pressure gauge for measuring a pressure of an output port; By controlling the solenoid valve and the second supply solenoid valve, the second
The positions of the first main valve and the second main valve are controlled by making the pressures in the diaphragm chamber and the fourth diaphragm chamber correspond to the measured values of the pressure gauge.

According to the structure of the present invention, since the exhaust solenoid valve conventionally provided is not used, no noise is generated by the exhaust solenoid valve. Since the second diaphragm chamber and the fourth diaphragm chamber each include a supply solenoid valve and an orifice, the pressure in each diaphragm chamber is controlled by controlling each supply solenoid valve. Here, by using a pulse-type solenoid valve as the first and second supply solenoid valves, control with higher responsiveness and higher responsiveness is performed.

Since the pressure at the output port is measured by a pressure gauge, a pressure difference from the pilot pressure can be obtained quickly and easily. By controlling the two supply solenoid valves in accordance with the obtained differential pressure, the opening degrees of the two main valves are controlled, and the output port communicates with the supply air source or the exhaust pipe. Further, in this configuration, by providing two main valves, air supply and exhaust to the output port can be performed simultaneously. Therefore, even if there is a variation in the exhaust amount of the orifice, the variation can be absorbed by controlling the two main valves of supply and exhaust, so that higher accuracy and responsiveness can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying a pilot type proportional pressure control valve system of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows the configuration of a first embodiment of a pilot pressure proportional control valve system. The pilot pressure proportional control valve 10 is connected to the supply port 1
1, an output port 12, and an exhaust port (not shown) are formed in the body. The pilot valve 14 has a diaphragm structure, and includes a first diaphragm chamber 16 and a second diaphragm chamber 17 isolated by the pilot valve 14. A pilot valve shaft 15 is fixed to the pilot valve 14.

The body includes a first valve seat 18 and a second valve seat 18.
A valve seat 19 is formed, and a first valve body 20 that contacts or separates from the first valve seat 18 is slidably held. In addition, a second valve body 21 that contacts or separates from the second valve seat 19 is slidably held. The first valve body 20 is urged by a first return spring 22 in a direction in which it comes into contact with the first valve seat 18. The second valve element 21 is urged by a second return spring 23 in a direction in which the second valve element 21 contacts the second valve seat 19.

A supply solenoid valve 25 for connecting the first diaphragm chamber 16 to a supply air source and supplying air pressure to the first diaphragm chamber 16 and an orifice 26 for exhausting the first diaphragm chamber 16 are provided. . This solenoid valve uses a pulse-type solenoid valve that opens and closes in time according to the pulse frequency of an input pulse signal. Further, the second diaphragm chamber 17 is communicated with the output port 12, and a pressure gauge 29 for measuring the pressure Pc of the output port 12 is connected to constantly measure the pressure Pc. The measured pressure Pc is input to the control device 24, and the control device 24 controls the supply electromagnetic valve 25.

Next, the pilot type pressure proportional control valve 1
The operation of 0 will be described. FIG. 1 shows a neutral state, in which a first diaphragm chamber 16 and a second diaphragm chamber 1 are arranged.
7, the pilot valve 14 is not moving in any direction, so the pilot valve shaft 15 is also in a neutral state. That is, the first valve body 20 is pressed against the first valve seat 18 by the first return spring 22, and the second valve body 21
The output port 12 is not in communication with another port because it is pressed against the second valve seat 19 by the return spring 23. The pressure Pc of the output port 12 is measured by the pressure gauge 29.

Here, when the pressure Pc of the output port 12 is changed, the differential pressure between the desired pressure Pp and the pressure Pc measured by the pressure gauge 29 is set between the first diaphragm chamber 16 and the second diaphragm chamber 17. The supply electromagnetic valve 25 is controlled so as to cause the occurrence. In this embodiment, the supply electromagnetic valve 25 is a pulse-type electromagnetic valve, and is driven by an electric pulse signal having a constant period. By changing the time ratio between the ON time and the OFF time of the valve during the fixed pulse, the amount of air passing through the valve is changed. Thereby, an accurate valve opening can be obtained with a high response speed. Orifice 2
6 is substantially constant, a predetermined air pressure can be supplied to the first diaphragm chamber 16 by the opening degree of the supply solenoid valve 25. Since the pressure in the second diaphragm chamber 17 is Pc, the differential pressure is generated by setting the pressure in the first diaphragm chamber 16 to Pp.

When the pressure Pc is to be increased, the pressure of the first diaphragm chamber 16 is made larger than that of the second diaphragm chamber 17 by increasing the opening of the supply solenoid valve 25. As a result, the pilot valve 14 moves downward,
Since the pilot valve shaft 15 and the second valve body 21 are pushed down, the second valve seat 19 is opened. Therefore, the output port 12 communicates with the supply port 11, and air is supplied from the supply air source, so that the pressure Pc increases.

When the pressure Pc is reduced, the pressure of the first diaphragm chamber 16 is made smaller than that of the second diaphragm chamber 17 by reducing the opening of the supply solenoid valve 25. As a result, the pilot valve 14 moves upward, and the pilot valve shaft 15 and the first valve body 20 are pushed up, so that the first valve seat 18 is opened. Therefore, the output port 12 communicates with the exhaust port, and the air is exhausted, so that the pressure Pc decreases.

Therefore, according to the pilot type pressure proportional control valve 10 of this embodiment, no noise is generated because the exhaust solenoid valve is not used. Further, since the first diaphragm chamber 16 is provided with the supply solenoid valve 25 which is a pulse-type solenoid valve, an accurate opening can be obtained with high responsiveness. Since the communication amount of the orifice 26 is constant,
The first diaphragm chamber 1 depends on the opening degree of the supply solenoid valve 25.
6 is controlled, and it is possible to control the pilot valve 14 accurately and with high responsiveness. Further, since the pressure Pc of the output port 12 is constantly measured by the pressure gauge 29, a differential pressure from the output pressure Pp can always be obtained accurately and with high responsiveness. Therefore, the differential pressure between the first diaphragm chamber 16 and the second diaphragm chamber 17 is equal to the output pressure Pp and the pressure Pc.
The supply pressure can be controlled by the supply solenoid valve 25 accurately and with high responsiveness so as to obtain a pressure difference between the pressure and the pressure.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
Will be described in detail with reference to the drawings. FIG. 2 shows the configuration of a second embodiment of the pilot type pressure proportional control valve system. The pilot pressure proportional control valve 30
This is a configuration in which two two-port pressure proportional valves are integrated with their output ports in common. A supply port 31, an output port 32, and an exhaust port 33 are formed in the body. The pilot valves 34 and 35 have a diaphragm structure. The first diaphragm chamber 36 and the second diaphragm chamber 37 are isolated by the pilot valve 34, and the third diaphragm chamber 38 and the fourth diaphragm chamber 39 are isolated by the pilot valve 35. Be provided. A pilot valve shaft 40 is fixed to the pilot valve 34, and a pilot valve shaft 41 is fixed to the pilot valve 35.

The body includes a first valve seat 42 and a second valve seat 42.
A valve seat 43 is formed, and a first valve body 44 that contacts or separates from the first valve seat 42 is slidably held. Further, a second valve body 45 that comes into contact with or separates from the second valve seat 43 is slidably held. The first valve body 44 is urged by a first return spring 46 in a direction in which it comes into contact with the first valve seat 42. Further, the second valve body 45 is urged by a second return spring 47 in a direction in which it comes into contact with the second valve seat 43.

The first diaphragm chamber 36 and the third diaphragm chamber 38 are always connected to the exhaust port 33 and are exhausted. A first orifice 50 that connects the second diaphragm chamber 37 and the exhaust port 33 and exhausts the second diaphragm chamber 37, and a second orifice 51 that similarly exhausts the fourth diaphragm chamber 39 are attached. A first supply solenoid valve 52 for connecting the second diaphragm chamber 37 to a supply air source and supplying air pressure to the second diaphragm chamber 37;
Similarly, the second diaphragm chamber 39 supplies air pressure to the fourth diaphragm chamber 39.
A supply solenoid valve 53 is attached. Each of these solenoid valves uses a pulse-type solenoid valve that opens and closes in time according to the pulse frequency of the input pulse signal. Further, a pressure gauge 54 for measuring the pressure Pc is connected to the output port 32, and the pressure Pc is constantly measured. The measured pressure Pc is input to the control device 49, and the control device 49 causes the first supply solenoid valve 52 and the second supply
The supply solenoid valve 53 is controlled.

Next, the pilot type pressure proportional control valve 3
The operation of 0 will be described. FIG. 2 shows a neutral state, in which the first supply solenoid valve 52 and the second supply solenoid valve 5
3 is closed and the first orifice 50 and the second orifice 51 are in communication with the exhaust pipe, so that all of the first diaphragm chamber 36, the second diaphragm chamber 37, the third diaphragm chamber 38, and the fourth diaphragm chamber 39 are provided. Exhaust port 3
3 and the same pressure. Therefore, the pilot valve 34 and the pilot valve 35 are in a no-load state, the first valve body 44 is provided by the first return spring 46, and the second valve body 45 is provided by the second return spring 47.
, Respectively, against the first valve seat 42 or the second valve seat 43. Therefore, the output port 32 is not in communication with either the supply port 31 or the exhaust port 33.
The pressure Pc of the output port 32 is measured by the pressure gauge 54.

Here, when the pressure Pc of the output port 32 is changed, the two solenoid valves of the first supply solenoid valve 52 and the second supply solenoid valve 53 are controlled to change the second diaphragm chamber 3.
7. Change the pressure in the fourth diaphragm chamber 39. When increasing the pressure Pc, the pressure of the second diaphragm chamber 37 is increased by increasing the opening of the first supply solenoid valve 52. Thereby, the pilot valve shaft 40 and the first
Since the valve body 44 is moved to the left in the drawing, the first valve seat 42 is opened. Accordingly, the output port 32 and the supply port 31 communicate with each other, and air is supplied from the supply air source, so that the pressure Pc increases.

When reducing the pressure Pc, the second
The pressure of the fourth diaphragm chamber 39 is increased by increasing the opening of the supply solenoid valve 53. As a result, the pilot valve shaft 41 and the second valve body 45 are moved rightward in the drawing, so that the second valve seat 43 is opened. Therefore output port 3
2 communicates with the exhaust port 33 and exhausts air, so that the pressure Pc decreases.

In this embodiment, the pilot valve shaft 40 connecting the output port 32 and the supply port 31 is separate from the pilot valve shaft 41 connecting the output port 32 and the exhaust port 33. The opening degrees of both the first valve seat 42 and the second valve seat 43 can be controlled.
Therefore, finer and freer control is possible, and the responsiveness is further improved.

Therefore, according to the pilot type pressure proportional control valve 30 of this embodiment, the first supply solenoid valve 52 is provided in the second diaphragm chamber 37 and the fourth diaphragm chamber 39 is provided.
Is provided with a second supply solenoid valve 53. Since these solenoid valves are pulse-type solenoid valves, the control device 49 can obtain an accurate opening with high responsiveness. Since the communication amount between the first orifice 50 and the second orifice 51 is constant, it is possible to control the pilot valve 34 and the pilot valve 35 accurately and with high responsiveness by controlling these two solenoid valves. is there. Also, the pressure P of the output port 32
Since c is always measured by the pressure gauge 54, the pressure difference from the required output pressure can always be obtained accurately and with high responsiveness. Therefore, the pilot valve 34 and the pilot valve 35 are controlled in accordance with the pressure difference, and the first valve body 44 and the second valve body 4 are controlled.
5 can be controlled accurately and with high responsiveness.

Further, according to the pilot type pressure proportional control valve 30 of this embodiment, the circulation of the output port 32 and the supply port 31 is performed by the pilot valve 34, and the output port 3
2 and the exhaust port 33 are independently controlled by the pilot valve 35, so that both can be communicated by changing the opening degree, and control with higher responsiveness is possible.

The present embodiment is merely an example and does not limit the present invention. Therefore, naturally, the present invention can be variously modified and improved without departing from the gist thereof.

[0035]

According to the structure of the present invention, since the conventionally provided exhaust solenoid valve is not used, no noise is generated by the exhaust solenoid valve. By providing an orifice in the first diaphragm chamber in place of the exhaust solenoid valve, a constant amount of exhaust is constantly performed, and the supply air pressure is controlled by the supply solenoid valve. Therefore, by controlling the opening of the supply solenoid valve, the pressure in the first diaphragm chamber is controlled to the pilot pressure. Here, by using a pulse-type solenoid valve as the supply solenoid valve, control with higher responsiveness and higher responsiveness is performed. Further, the output port of the main valve communicates with the second diaphragm chamber, and the pressure is measured by a pressure gauge. Therefore, feedforward control is possible by predicting a pressure change corresponding to the measurement value of the pressure gauge and controlling the supply solenoid valve, so that the supply pressure can be controlled with higher accuracy and responsiveness. .

According to the structure of the present invention, since the conventionally provided exhaust solenoid valve is not used, no noise is generated by the exhaust solenoid valve. Since the second diaphragm chamber and the fourth diaphragm chamber each include a supply solenoid valve and an orifice, the pressure in each diaphragm chamber is controlled by controlling each supply solenoid valve. Here, by using a pulse-type solenoid valve as the first and second supply solenoid valves, control with higher responsiveness and higher responsiveness is performed. Also, since the pressure at the output port is measured with a pressure gauge,
The differential pressure from the pilot pressure can be obtained quickly and easily. By controlling the two supply solenoid valves in accordance with the obtained differential pressure, the opening degrees of the two main valves are controlled, and the output port communicates with the supply air source or the exhaust pipe. Furthermore, in this configuration, by providing two main valves, air supply and exhaust to the output port can be performed simultaneously. Therefore, higher responsiveness can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a pilot pressure proportional control valve according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a configuration of a pilot pressure proportional control valve according to a second embodiment.

FIG. 3 is a sectional view showing a configuration of a conventional pilot pressure proportional control valve.

[Explanation of symbols]

 Reference Signs List 10 pilot-type pressure proportional control valve 14 pilot valve 16 first diaphragm chamber 17 second diaphragm chamber 25 supply solenoid valve 26 orifice 29 pressure gauge 30 pilot-type pressure proportional control valve 31 supply port (input port of first main valve) 32 Output Port 33 Exhaust Port (Input Port of Second Main Valve) 34 Pilot Valve 35 Pilot Valve 36 First Diaphragm Chamber 37 Second Diaphragm Chamber 38 Third Diaphragm Chamber 39 Fourth Diaphragm Chamber 50 First Orifice 51 Second Orifice 52 First supply solenoid valve 53 Second supply solenoid valve 54 Pressure gauge

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (2)

[Claims] 1. A pilot type proportional pressure control valve system for controlling the pressure of a fluid flowing through a main valve by controlling an opening degree of a main valve by controlling an air pressure supplied to the pilot valve, wherein the pilot valve has a diaphragm. A first diaphragm chamber isolated by the diaphragm;
A diaphragm chamber, wherein the second diaphragm chamber is communicated with an output port of the main valve, and a supply solenoid valve provided between the first diaphragm chamber and a supply air source; An orifice provided between the exhaust pipe and a pressure gauge for measuring the pressure of the output port, and controlling the supply solenoid valve to measure the pressure in the first diaphragm chamber by the measurement value of the pressure gauge By responding to
A pilot pressure proportional control valve system, wherein the position of the main valve is controlled. 2. A pilot-type pressure proportional control valve for controlling the pressure of the fluid flowing through the main valve by controlling the opening degree of the main valve by controlling the air pressure supplied to the pilot valve,
In the pilot pressure proportional control valve system in which the output ports of the respective main valves are integrally formed in common, the input port of the first main valve is connected to the supply air source, and the input port of the second main valve is connected to the exhaust pipe. Wherein each of the pilot valves has a diaphragm structure, a first diaphragm chamber and a second diaphragm chamber isolated by a first diaphragm of a first pilot valve, and a third diaphragm isolated by a second diaphragm of a second pilot valve. A first diaphragm chamber and a fourth diaphragm chamber, the first diaphragm chamber and the third diaphragm chamber being communicated with an exhaust pipe, and a first supply electromagnetic provided between the second diaphragm chamber and a supply air source. A valve, a first orifice provided between the second diaphragm chamber and an exhaust pipe, a fourth diaphragm chamber and a supply air source A second orifice provided between the fourth diaphragm chamber and the exhaust pipe, and a pressure gauge for measuring the pressure of the output port, The first main valve and the second main valve are controlled by controlling the first supply solenoid valve and the second supply solenoid valve so that the pressure in the second diaphragm chamber and the pressure in the fourth diaphragm chamber correspond to the measurement value of the pressure gauge. A pilot pressure proportional control valve system, wherein the position of the second main valve is controlled.