JP2787394B2 - Automatic setting pressure reducing valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve for adjusting the elastic force of a pressure setting spring for setting a fluid pressure on the secondary side by changing the advance / retreat position of an adjusting screw. Automatic setting pressure reducing valve to be performed.
The automatic setting pressure reducing valve is configured to change the biasing state of the pressure setting spring by rotating an adjusting screw screwed to a bearing formed on the valve casing of the pressure reducing valve by an electric motor and moving the adjusting screw in the axial direction. The drive of the electric motor is controlled based on the relationship between the position of the adjusting screw and the set pressure. In this automatic setting pressure reducing valve, as the adjusting screw is tightened to compress the pressure setting spring, the force generated by the pressure setting spring increases, and there has been a problem that the torque of the actuator is insufficient.

[0002]

2. Description of the Related Art A solution to this problem is disclosed in Japanese Patent Publication No. Hei 3-8.
No. 1166. In this method, the adjusting member is attached to the adjusting screw, and the adjusting member is tightened by arranging a magnetic member that attracts the magnetic member when the adjusting screw is tightened, opposite to the adjusting member. Accordingly, the attraction force of the magnetic member is increased to absorb the force generated by the pressure setting spring, thereby preventing the actuator from running out of torque.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
While the force generated by the pressure setting spring is proportional to the tightening amount of the adjusting screw, the attraction force of the magnetic member is proportional to the square of the tightening amount, so that insufficient torque of the actuator cannot be effectively prevented. There was a problem that required an actuator having a relatively large torque. Therefore, a technical problem of the present invention is to make the generated force of the pressure setting spring proportional to the absorbing force for absorbing the generated force.

[0004]

The technical means of the present invention, which has been taken to solve the above technical problem, is to move an adjusting screw screwed to a bearing formed on a valve casing in the axial direction by rotating the adjusting screw. is, the pressure setting spring on one side by the movement
Pressure-responsive member on which other elastic force acts and secondary pressure acts on the other surface
Is configured to adjust the set pressure of the valve by changing the energizing state of the pressure setting spring for an automatic setting pressure reducing valve in which the axial movement of the adjusting screw to perform by an actuator, said pressure responding member Separately, a bellows having one end abutting on the fixed wall of the valve casing and the other end abutting on the adjusting screw is arranged, and a secondary pressure is introduced into the bellows to urge the adjusting screw against the pressure setting spring. It was made.

[0005]

The operation of the above technical means is as follows.
The adjusting screw receives a bellowing force due to the generated force of the pressure setting spring and the secondary pressure in the direction opposite to the generated force according to the tightening amount. Since the secondary pressure is proportional to the position of the adjusting screw, that is, the amount of compression of the pressure setting spring, the force generated by the pressure setting spring and the force of the bellows opposed thereto are proportional. Therefore, the generated force of the pressure setting spring received by the adjusting screw can be canceled by the force of the bellows, and even if the actuator has a small torque, the adjusting screw can be rotated and moved in the axial direction.

[0006]

An embodiment showing a specific example of the above technical means will be described (see FIG. 1). Inlet 1 and outlet 2 in valve casing,
A main valve port 3 is formed, and the main valve port 3 is opened and closed by a main valve body 5 urged in a valve closing direction by a main valve spring 4. The piston 9 is slidably disposed in the cylinder 10, and the lower piston rod of the piston 9 abuts on the upper projection of the main valve body 5. The fluid pressure on the outlet 2 side acts on the lower surface of the piston 9, and the fluid pressure on the inlet 1 side is introduced into the upper surface of the piston 9 under control of the pilot valve 13 through the primary pressure passages 11 and 12. Pilot valve 1
3 is urged by a spring in the valve closing direction and is pressure-responsive via a valve rod.
It hits the lower surface of the diaphragm 14 as a member, and receives an operating force in the valve opening direction due to its displacement.

The lower end of a pressure setting spring 16 abuts on the upper surface of the diaphragm 14 via a diaphragm retainer 15, and an elastic force acts. The lower end of the adjusting screw 19 contacts the upper end of the pressure setting spring 16 via the spring receiving member 17 and the ball 18, and the amount of compression of the pressure setting spring 16 is adjusted by the advance and retreat of the adjusting screw 19 to rotate the diaphragm. The elastic force acting on 14 can be adjusted. Adjustment screw 19
Is screwed to a bearing 21 fixed to a spring housing case 20 which forms a part of the valve case. Diaphragm 1
The lower surface of 4 faces the diaphragm chamber 25 through the secondary side detection passage 24 communicating with the outlet 2.

When the adjusting screw 19 rotates left and right, the elastic force of the pressure setting spring 16 for pushing down the diaphragm 14 changes. Therefore, when the diaphragm 14 is displaced downward, the pilot valve 13 is pushed down and opened, and the fluid at the inlet 1 is introduced above the piston 9 through the passages 11 and 12, and
The main valve element 5 is pushed down by the piston 9 to open the main valve port 3, and the fluid at the inlet 1 flows to the outlet 2. When the pressure on the secondary side rises, the diaphragm chamber 2 passes through the secondary side detection passage 24.
5 also increases, and the diaphragm 14 is displaced upward. As a result, the pilot valve 13 is pushed up to close the valve, the supply fluid above the piston 9 decreases, the main valve body 5 is pushed up by the main valve spring 4, and the main valve port 3 is closed. By repeating the above, the pressure on the secondary side is maintained at a desired value.

To change the set pressure, the adjusting screw 19 is rotated to change the urging force of the pressure setting spring 16 on the diaphragm 14. A mechanism for rotating the adjusting screw 19 will be described below. Actuator 2 on top of adjusting screw 19
6, a fitting hole 28 for fitting the output shaft 27 is formed, and two notches 29 are formed around the fitting hole 28. Output shaft 2
7, the pin 30 is penetrated and fixed, the both ends of the pin 30 are fitted into the notches 29, and the output shaft 27 is fitted into the fitting holes 28. Actuator 26 is a reduction gear 3 having an output shaft 27
1 and a motor 32 coupled to the input side of the speed reducer 31. The motor 32 is fixed to a mount 33 fixed to the housing case 20 and covered by a cover 34. A cylindrical bellows 22 having one end in contact with the mounting base 33 and the other end in contact with the step of the adjusting screw 19 is arranged around the adjusting screw 19. Belo
A secondary pressure is introduced into the interior of the nozzle 22 via a conduit 23.

A control means 35 for supplying a drive signal to the electric motor 32 is disposed in the cover 34. The relationship between the position of the adjusting screw 19 and the set pressure is stored in the control means 35 in advance. In response to rotation of the output shaft 27 at a fixed position, the adjusting screw 19 moves axially while rotating via the pin 30. A potentiometer 36 for detecting the position of the adjusting screw 19 in the axial direction is mounted on the mounting table 32.

When an arbitrary set pressure to be set is input, the control means 35 rotates the electric motor 32 based on the functional relationship between the position of the adjusting screw 19 and the set pressure, and sets the adjusting screw 1.
9 is adjusted to adjust the elastic force of the pressure setting spring 16. When it is detected by the potentiometer 36 that the adjusting screw 19 has been displaced to the position to be stopped, the control means 3
5 stops the drive of the electric motor 32. Secondary pressure is introduced into bellows 22 via conduit 23. The force of the bellows 22 due to the secondary pressure cancels out the generated force of the pressure setting spring 16 received by the adjusting screw 19.

[0012]

As described above, according to the present invention, the bellows in which the secondary pressure is applied cancels the force generated by the pressure setting spring, so that it is possible to use an actuator with a small torque. it can. Therefore, a small and inexpensive automatic setting pressure reducing valve can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an automatic setting pressure reducing valve according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inlet 2 Outlet 3 Main valve port 5 Main valve body 14 Diaphragm 16 Pressure setting spring 19 Adjusting screw 21 Bearing 22 Bellows 23 Conduit 26 Actuator 27 Output shaft 35 Control means 36 Potentiometer

Claims (1)

(57) [Claims] 1. A valve casing is rotated the screw bound adjusting screw in the bearing portion formed in the moving axially, the two on the other side acts an elastic force of the pressure setting spring is on one side by the movement
An automatic set pressure reducing mechanism configured to adjust the set pressure of the valve by changing the biasing state of the pressure setting spring with respect to the pressure responsive member on which the next pressure acts, and to move the adjusting screw in the axial direction by an actuator. In the valve, before
Apart from the pressure responsive member, a bellows is disposed , one end of which contacts the fixed wall of the valve casing and the other end of which contacts the adjusting screw,
An automatic setting pressure reducing valve that introduces secondary pressure into the bellows and urges the adjusting screw against the pressure setting spring.