JPH017901Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an electromagnetic valve, and particularly to an electromagnetic valve in which a main valve switches between three positions: an intermediate position and positions on both sides thereof.

[Background technology]

When it is desired to stop a piston at an intermediate position in a fluid pressure operated device such as an air cylinder, a three-position direct acting type or pilot type solenoid valve is used.

In such a three-position solenoid valve, when the main valve is operated between three positions, an intermediate position and positions on both sides, a coil spring is used to return the main valve to the intermediate position, and the spring force is used to return the main valve to the intermediate position. Normally, the main valve is returned to an intermediate position.

However, since the magnitude of such spring force varies depending on the position of the main valve, the return operation of the main valve to the intermediate position becomes unstable, and the speed of the return operation fluctuates, making it difficult to return quickly. There are other problems.

Therefore, in order to solve this problem, an auxiliary piston that returns the main valve to the intermediate position and a spring that applies a biasing force to the auxiliary piston to return the main shaft are provided at both ends of the main valve in the axial direction. There is a solenoid valve with a structure (for example, described in Japanese Patent Publication No. 57-59469).

However, in this electromagnetic valve, since the auxiliary piston and its spring are respectively disposed on both ends of the main valve in the axial direction, the axial dimension becomes large due to the space therebetween.

Further, since a spring must be provided for each auxiliary piston, at least one pair of springs is required, and it is also necessary to form a pair of fluid chambers for operating the auxiliary piston.

[Purpose of invention]

An object of the present invention is to provide a solenoid valve that can be made smaller and have a simpler structure, in which the main valve can be reliably returned to an intermediate position.

[Summary of the idea]

The present invention is a solenoid valve that switches the main valve between three positions, an intermediate position and positions on both sides thereof, and a pair of main pistons that return the main shaft of the main valve disposed at both ends toward the intermediate position. Auxiliary pistons are arranged between the main pistons facing each other, and a spring for returning the main shaft to an intermediate position is provided in the space between the pair of auxiliary pistons, and the space is connected to the auxiliary pistons. This type of electromagnetic valve can be made smaller by using a structure in which a fluid pressure chamber is used for operation, and the return operation of the main valve to the intermediate position is performed by the biasing force of the spring and the fluid pressure applied to the auxiliary piston. and simplification of the structure.

〔Example〕

FIG. 1 shows a sectional view of a solenoid valve that is an embodiment of the present invention.

The solenoid valve in this embodiment is a so-called three-position pilot type solenoid valve, and has a structure in which a main valve portion 1 is provided with pilot valves 2, 2 (only one of which is shown in cross-sectional view) on both sides.

The main valve portion 1 has a so-called spool valve type structure, and a main shaft 4 is provided at the axial center of the main body 3 so as to be freely movable in the axial direction. Lip seals 5, 6, 7, and 8 are fitted to the main shaft 4 at four locations, and V-shaped gaskets 9 and 10 are provided near both ends of the main shaft 4 and the main body 3. Further, the main body 3 is formed with a supply port 11 for supplying pressurized air, output ports 12 and 13, and exhaust ports 14 and 15 for exhaust. Each of the output ports 12 and 13 communicates with each of the chambers formed on both sides of the piston of the cylinder 16.

On the other hand, the pilot valve 2 includes a solenoid 32 wound around a bobbin 31, a core 33 in the bobbin 31, a plunger 34, and a plunger spring 3.
5, shedding coil 36, plunger 34
It has a valve body 37 which is provided at the tip and opens and closes the passage 51 and communicates with the space 53, a movable valve body 38 which is interlocked with the plunger 34 by a pin P, a spring 39 which biases the movable valve body 38, and a cap 40. are doing.

The pin P is fitted into a hole passing through the inside of the pilot valve 2 with a gap serving as a fluid passage. An adapter cap 17 is coupled to the left end of the main body 3, and a housing portion 17a in which a discharge port 26 is formed is formed at both ends of the main body 3.
are arranged respectively. This adapter cap 1
7, two auxiliary pistons 4 are slidably fitted to the left end of the main shaft 4 via a spring 43.
1 and 42 are arranged. Further, an O-ring 44, a V-shaped seal 45 and an O-ring 4 are provided on the inner and outer circumferential sides of each of the auxiliary pistons 41 and 42, respectively.
6. A V-shaped seal 47 is fitted.

Furthermore, a main piston 48 is provided on the left and right end surfaces of the main shaft 4.
is fixed with bolt 49. Further, a V-shaped seal 50 is fitted on the outer peripheral side of the main piston 48.

Air pressure from the supply port 11 is constantly supplied between the auxiliary pistons 41 and 42 in this embodiment through the passages 51 and 52, and the main shaft 4 is It is maintained at the intermediate position shown in FIG. Furthermore, the air pressure from the supply port 11 is supplied and discharged from the passage 51 to the space 53 on the pilot valve 2 side of the main piston 48 by switching control of the pilot valve 2, and the main shaft 4 is moved from the intermediate position to the right or left side. It's getting old.

To explain the operation of this embodiment, Fig. 1 shows the main shaft 4.
If you want to move the main shaft 4 to the right from this state while keeping it at the intermediate position, when the pilot valve 2 on the left side is energized and switched, the air pressure from the supply port 11 will pass through the passage 51 and pass through the pilot valve 2. The main piston 48 moves the main shaft 4 to the right against the pressing force of the auxiliary piston 42 and the urging force of the spring 43. At this time, the auxiliary piston 4
2 moves to the right at the same time as the main shaft 4.

When returning the main shaft 4 to the intermediate position, the pilot valve 2 is switched by cutting off the power to the left pilot valve 2, and when the air pressure supplied to the space 53 is discharged, the pressing force of the auxiliary piston 42 and the spring 4
The main shaft 4 is maintained at an intermediate position by the biasing force 3.

Further, when the main shaft 4 is moved to the left side, the right pilot valve 2 is energized to perform switching control, and when the main shaft 4 is returned to the intermediate position, the energization is cut off.

In this embodiment, the space 5 of the main piston 48
3, by supplying and discharging air pressure from the supply port 11 while switching and controlling it with the pilot valve 2, the biasing force of the spring 43 and the auxiliary pistons 41, 42 are
By using the pressing force of , the main shaft 4 of the main valve portion 1 can be quickly and reliably moved from the intermediate position in FIG. 2 to the left or right or returned to the intermediate position.

In addition, in the embodiment, at an intermediate position of the main shaft 4, the supply port 11, the output ports 12, 13, and the output port 1
This is a so-called closed center three-position solenoid valve in which the supply ports 1 and 13 and the discharge ports 14 and 15 are closed.
1 and the output ports 12 and 13 are closed, and the output ports 12 and 1 are closed.
It can also be implemented in a so-called exhaust center type three-position solenoid valve, etc., which communicates the discharge ports 14 and 15 with the exhaust center.

Further, the main pistons 18, 18 in the embodiment are connected to the main shaft 4.
It is also possible to simply touch without fixing it to both ends of the
The right main piston 48 in the second embodiment is also connected to the main shaft 4 in the same way.
It is clear that it is sufficient to simply abut it without fixing it to.

〔effect〕

A pair of auxiliary pistons are disposed opposite to each other between the main pistons on both ends of the main shaft of the main valve, and a spring for returning the main shaft to an intermediate position is provided in the space between the pair of auxiliary pistons. At the same time, by using a structure in which the space is used as a fluid pressure chamber for operating the auxiliary piston, the main shaft can be shortened in the axial direction, and the spring for operating the pair of auxiliary pistons can be used in common with the fluid pressure chamber. Therefore, this type of solenoid valve can be made smaller and have a simpler structure.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a solenoid valve that is an embodiment of the present invention. 1... Main valve part, 2... Pilot valve, 3... Main body, 4
...Main shaft, 11... Supply port, 12, 13... Output port, 1
4, 15...Discharge port, 16...Cylinder, 17...Adapter cap, 18...Main piston, 20...Spring,
21... Auxiliary piston, 25... Passage, 30... Space,
32...Solenoid, 34...Plunger, 41,4
2... Auxiliary piston, 43... Spring, 48... Main piston, 51, 52... Passage, 53... Space.

Claims (1)

[Scope of utility model registration request] In a solenoid valve that switches the main valve between three positions: an intermediate position and positions on both sides thereof, a pair of auxiliary pistons that return the main shaft of the main valve to the intermediate position, with the main pistons disposed at both ends, move toward each other. A spring is provided between the main pistons facing each other, and a spring is provided in the space between the pair of auxiliary pistons for returning the main shaft to an intermediate position. 1. A solenoid valve, characterized in that the main valve has a pressure chamber, and the return operation of the main valve to an intermediate position is performed by the biasing force of the spring and the fluid pressure applied to the auxiliary piston.