JP2787391B2 - 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.

[0002]

2. Description of the Related Art A conventional automatic setting pressure reducing valve is disclosed in, for example, JP-A-63-20603. This is configured to change the biasing state of the pressure setting spring by rotating an adjusting screw screwed to a bearing portion 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 screw and the set pressure.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
In a relatively short period of time, the bearing part of the valve casing and the adjusting screw wear out, which causes the relationship between the position of the adjusting screw and the set pressure to change, and the secondary fluid pressure can be adjusted to the set pressure. There was a problem that disappeared. This is because adjusting screws and valve casings are generally made of brass or cast iron in consideration of easiness of manufacture and cost, and therefore have relatively low hardness and are easily worn. Therefore, a technical problem of the present invention is to prevent the wear of the adjusting screw and the bearing part of the valve casing so that the fluid pressure on the secondary side can be accurately adjusted to the set pressure for a long period of time. .

[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
The setting pressure of the valve is adjusted by changing the biasing state of the pressure setting spring with respect to the pressure setting spring, and the axial movement of the adjusting screw is performed by the actuator based on the relationship between the position of the adjusting screw and the set pressure. In the automatic setting pressure reducing valve described above, a magnet is attached to an adjusting screw or a bearing portion, and a magnetic fluid attracted by the magnet is arranged in a screw portion between the adjusting screw and the bearing portion.

[0005]

The operation of the above technical means is as follows.
The magnetic fluid is made by suspending magnetic particles in a dispersion medium, and iron oxides such as ferrite and magnetite are used as the magnetic particles, and paraffin, water, ester oil, and silicon are used as the dispersion medium. Oil or the like is used. Since the magnetic fluid is arranged in the thread between the adjusting screw and the bearing of the valve casing, the adjusting screw and the bearing do not wear out, so that the relationship between the position of the adjusting screw and the set pressure is not correct. Will not occur.

[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. An annular groove is formed in the bearing portion 21 from the lower end, and the cylindrical magnet 22 is fixed. The magnetic fluid 23 is arranged in a thread between the adjusting screw 19 and the bearing 21. The lower surface of the diaphragm 14 passes through a secondary side detection passage 24 communicating with the outlet 2 and a diaphragm chamber 25.
Face

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 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, moves the adjusting screw 19 forward and backward, and presses the pressure setting spring 16.
Adjust the elastic force of When the potentiometer 36 detects that the adjusting screw 19 has been displaced to the position to be stopped, the control means 35 stops driving the electric motor 32. In the above embodiment, the magnet is attached to the bearing portion, but it can be attached to the adjusting screw.

[0012]

As described above, according to the present invention, since the magnetic fluid is disposed in the screw portion between the adjusting screw and the bearing portion of the valve casing, the adjusting screw and the bearing portion do not wear. Therefore, it is possible to obtain an automatically set pressure reducing valve capable of accurately adjusting the fluid pressure on the secondary side to the set pressure over a long period of time.

[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 Adjustment screw 21 Bearing part 22 Magnet 23 Magnetic fluid 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
The setting pressure of the valve is adjusted by changing the biasing state of the pressure setting spring with respect to the pressure response member on which the next pressure acts, and the axis of the adjusting screw is adjusted based on the relationship between the position of the adjusting screw and the setting pressure. In an automatic setting pressure reducing valve in which the direction is moved by an actuator, a magnet is attached to an adjusting screw or a bearing, and a magnetic fluid attracted by the magnet is arranged in a screw between the adjusting screw and the bearing, and the automatic setting pressure reducing valve valve.