JPH0342294Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The invention is a normally open type valve that is equipped with a pilot valve driven by electromagnetic force, and the main valve is opened and closed by the pressure difference between the inlet and the back chamber. It relates to electromagnetic valves and is used to control the opening and closing of passages in various fluid systems.

[Prior art and its problems] A normally open solenoid valve, in which the pilot valve opens during a power outage to open the main valve, but closes when power is applied to close the main valve, is fixedly located on the central axis of the solenoid coil. The pilot valve is connected to the tip of the plunger so that the back chamber of the main valve body communicates with the outlet side of the valve body during a power outage, but is cut off when the power is turned on. It is set up and configured. Therefore, the total lift of the pilot valve element is the lift of the main valve element plus its own lift, which not only increases the overall height, but also causes the operation of the pilot valve element to be opposite to that of a normally closed solenoid valve. Therefore, it is unavoidable that the distance between the plunger and the pole piece becomes considerably large. Therefore,
Not only is it not possible to reduce the overall size due to the increased overall height and the need to increase the size of the electromagnetic coil to increase the attraction force, but also because the attraction force of the plunger is strong, when it hits a pole piece. This can cause a large impact and reduce durability.

[Purpose of the invention] The purpose of the invention is to provide a normally open solenoid valve whose pilot valve operates in the same direction as a normally closed solenoid valve, which is small in size and which can open and close a fluid passage with a weak suction force. .

[Means for Solving the Problems] In the present invention, a plunger and a pole piece are arranged movably in the direction of the central axis with the plunger facing upward, and the inlet and outlet of the valve body are arranged on the central axis of the electromagnetic coil. A main valve body facing the main valve seat between the pole pieces is disposed on the central axis with its upper surface in contact with the lower end face of the pole piece, and the main valve body communicates the back chamber on one side of the pole piece with the inlet. a pilot valve hole and a pilot valve seat that communicate with the back chamber and the outlet; a pilot valve body facing the pilot valve seat; and a direction in which the pilot valve body is separated from the pilot valve seat. A return spring acting on the pole piece is built into the lower end of the pole piece, the pilot valve body is connected to the plunger by a push rod passing through the pole piece, and the distance between the plunger and the pole piece is set at the distance between the plunger and the pole piece. A means for solving the above-mentioned problems is achieved by configuring the opening/closing lift of the pilot valve body to be equal to the opening/closing lift of the pilot valve body.

[Operation] When the electromagnetic coil is out of power, the pilot valve element is separated from the pilot valve seat by the elastic force of the return spring, opening the back chamber to the outlet and opening the main valve. When the electromagnetic coil is energized, the plunger is attracted to the pole piece, and the pilot valve element is seated on the pilot valve seat, increasing the pressure in the back chamber into which the fluid pressure at the inlet is introduced. The total lift of the pilot valve body is independent of the lift of the main valve body, and is only its own opening/closing lift, and since the distance between the plunger and the pole piece is equal to the opening/closing lift of the pilot valve body, after seating, the main valve body, pole piece , the plunger moves down together to close the main valve.

The distance between the plunger and the pole piece is equal to the opening/closing lift of the pilot valve body itself, so it is small; the electromagnetic coil can be made smaller because it can be attracted with a weak suction force; the pilot valve body and its return spring are built into the pole piece. As a result, the overall size is reduced.

[Embodiment] An embodiment of the present invention will be described based on the drawings. A fluid inlet 1 and an outlet 2, and a main valve seat 3 between them.
A cylindrical guide 5 is provided vertically above the main valve seat 3 of the valve body 6 having It is movably fitted. A lid 9 is screwed and fixed to the upper part of the guide 5, and a coil case 11 containing a built-in electromagnetic coil 10 is placed and fixed on the upper end of the cover 9. A plunger 13 and a pole piece 14 are fitted into the guide tube 12 so as to be movable in the direction of the central axis, with the plunger 13 facing upward.

The main valve body 7 has a pilot valve seat 17 provided above with a primary pressure passage 8 that communicates a space, that is, a back chamber 15, with the inlet 1, and a pilot valve hole 16 that opens the back chamber 15 to the valve hole 4. Lower end cylindrical portion 14 of pole piece 14
The end face of the main valve body 7 surrounds the pilot valve seat 17.
is in contact with the top surface of A pilot valve body 18 disposed opposite the pilot valve seat 17 is built into the lower end cylindrical portion 14a, is actuated by a return spring 19 that acts in a direction away from the pilot valve seat 17, and is inserted through the pole piece 14. A push rod 20 protruding from the plunger 13 is connected to the plunger 13, and the pilot valve hole 16, pilot valve seat 17, and pilot valve body 18 constitute a pilot valve 21. Furthermore, the distance between the plunger 13 and the pole piece 14 is the same as that of the pilot valve body 18 regardless of the lift of the main valve body 7.
Its own opening and closing is equal to the lift.

In this embodiment configured in this way, the electromagnetic coil 1
During a power outage when power is not supplied to 0, the pilot valve body 1
8 is separated from the pilot valve seat 17 by the elastic force of the return spring 19, and passes through the primary pressure passage 8 to the back chamber 1.
The fluid pressure at the inlet 1 introduced into the lower end cylindrical portion 14
The pressure in the back chamber 15 does not increase because the air is discharged through the through hole 22 of a, the pilot valve hole 16, and the main valve hole 4 to the outlet 2. Therefore, the pressure in the back chamber 15 does not increase. The fluid pressure pushes up the main valve body 7 and the pole piece 14 to open the main valve (the first,
(See Figure 2).

When the electromagnetic coil 10 is energized, the plunger 13 is attracted to the pole piece 14, and the push rod 20 pushes the pilot valve body 18 to seat on the pilot valve seat 17 and close the pilot valve hole 16. That is, since the fluid pressure at the inlet 1 introduced into the back chamber 15 is not released, the pressure in the back chamber 15 increases, and while the pilot valve hole 16 is maintained in a closed state, the main valve body 7, the pole piece 14,
The plunger 13 is lowered together, and the main valve body 7 is seated on the main valve seat 3, closing the main valve hole 4 as shown in FIG.

Next, when the electromagnetic coil 10 is turned off, the plunger 13 is released from the pole piece 14, so the pilot valve body 18 is separated from the pilot valve seat 17 by the elastic force of the return spring 19, and the fluid pressure in the back chamber 15 is released from the outlet. 2, the main valve body 7 is pushed up by the fluid pressure at the inlet 1 and returns to the state shown in FIGS. 1 and 2.

[Effect of the invention] According to the invention, the plunger and the pole piece are disposed on the central axis of the electromagnetic coil so as to be movable in the direction of the central axis, and the lower end surface of the pole piece is brought into contact with the upper surface of the main valve body. and a pilot valve hole are provided in the main valve body, the pilot valve body and a return spring are built into the lower end of the pole piece, and the distance between the plunger and the pole piece is made equal to the opening/closing lift of the pilot valve body. , the overall height can be made sufficiently low. In addition, since the distance between the plunger and the pole piece is as small as the opening/closing lift of the pilot valve body itself, regardless of the lift of the main valve body, suction can be achieved with a weak suction force, and a small electromagnetic coil can be used to reduce the overall size. can. Furthermore, due to the small spacing, when the plunger hits the pole piece, the impact is small and durability is excellent, and the pilot valve and the main valve can be opened and closed reliably.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention when the valve is open, FIG. 2 is an enlarged partial view of FIG. 1, and FIG. 3 is a partial vertical cross-sectional view when the valve is open. 1...Inlet, 2...Outlet, 3...Main valve seat, 6...
... Valve body, 7 ... Main valve body, 8 ... Primary pressure passage, 1
0... Electromagnetic coil, 13... Plunger, 14...
... pole piece, 15 ... back chamber, 16 ... pilot valve hole, 17 ... pilot valve seat, 18 ... pilot valve body, 21 ... pilot valve.

Claims (1)

[Scope of utility model registration request] A plunger and a pole piece are arranged on the central axis of the electromagnetic coil so as to be movable in the direction of the central axis, with the plunger facing upward, and a main valve body is arranged opposite to the main valve seat between the inlet and outlet of the valve body. The main valve body is arranged on the central axis with its upper surface in contact with the lower end surface of the pole piece, and the main valve body communicates with the primary pressure passage that communicates the back chamber on one side of the pole with the inlet and the back chamber with the outlet. A pilot valve hole and a pilot valve seat are provided, and a pilot valve body facing the pilot valve seat and a return spring acting in a direction to separate the pilot valve body from the pilot valve seat are built in the lower end of the pole piece. The pilot valve body is of a normally open type, and the pilot valve body is connected to the plunger by a push rod passing through the pole piece, and further, the distance between the plunger and the pole piece is equal to the opening/closing lift of the pilot valve body. solenoid valve.