JPS6126691Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pilot type switching valve that slows down the moving speed of the valve at the end of its closing, thereby alleviating the shock in the main circuit when the valve is closed.

Conventionally, in this type of pilot type switching valve, as shown in FIG. As shown in FIG. A method in which a speed control valve (speed controller) 9 is connected in the middle of the pilot passage between the switching valve 7 and the pilot valve 8, and the speed when the switching valve 7 is opened and closed is controlled by the speed control valve 9. It has been known.

However, in these conventional devices, the method shown in FIG. 1 has the disadvantage that the speed control section is a fixed type, and therefore cannot be controlled in response to pressure fluctuations of the pilot fluid. In addition, although the method shown in Figure 2 can cope with pressure fluctuations in the pilot fluid, the speed is controlled in the same way from the start to the end of valve closing, so the overall switching speed related to valve operation is This had the disadvantage that it was slow. Furthermore, both types have the disadvantage that if the pilot fluid pressure fluctuates during operation, the speed changes accordingly, and they cannot respond to pressure fluctuations.

The present invention provides a pilot type switching valve that can always close the valve at a constant delay speed without being affected by pressure fluctuations of the pilot fluid at the end of closing the valve.

The details of the present invention will be explained below using examples.
As shown in FIG. 3, the valve body 10 has a valve chamber 1 inside.
1 and a piston chamber 12 following it, connection ports 13 and 14 to the main circuit are opened in the valve chamber 11,
The valve seat 1 is inserted into the valve chamber 11 between the connection ports 13 and 14.
5 is formed. There is a spool 1 in the valve chamber 11.
6 is slidably inserted, and a pet portion 17 is formed at one end of the valve seat 15 to form a two-way valve. A piston 18 is slidably inserted into the piston chamber 12 and is integrally configured to interlock with the spool 16. The spool 16 is normally pressed to the right in the figure by the spring 19, and the two-way valve is in a closed state. A pilot valve 20 for supplying and discharging pilot fluid to and from the piston chamber 12 is mounted on the side surface of the valve body 10. This pilot valve 20 has a supply port 21, an output port 22, and a discharge port 23. The supply port 21 is connected to a fluid pressure source P, and the output port 22 is connected to a communication port 24 opened to the side surface of the valve body 10. This port 24 communicates with the right side chamber 12a of the piston 18.

On the other hand, a breathing hole 25 that opens to the outside is opened in the left side chamber 12b of the piston 18, that is, the back pressure side chamber, and a check valve 26 and a variable crest valve 27 are installed in parallel in the middle of this breathing hole 25. It constitutes a hole control section. Furthermore, the check valve 26 is installed in a direction to block the flow from the outside, and the variable swell valve 27 is configured so that the amount of swell can be adjusted from the outside, as is clear from the figure. In addition, number 28 in the figure
The figure shows the breathing hole of the chamber in which the spring 19 is housed.

To explain the operation of the embodiment of the present application having the above configuration, FIG. 3 shows that the spool 16 is pressed to the right by the force of the spring 19,
shows a state in which the valve is seated on the valve seat 15 and is in the valve closed position.

First, when the pilot valve 20 is turned on, the supply port 21 and the output port 22 communicate with each other, and the pressure fluid flows through the output port 2.
2 through the port 24 to the piston chamber 18 right side chamber 1
2a and presses the piston 18. and piston 18 and spool 1 against the force of spring 19.
6 to the left in the figure, poppet part 17 and valve seat 1
5 to the open position, and when the piston 18 moves to the left, the air in the piston left chamber 12b passes through the check valve 26 and opens the breathing hole 25 in the above-mentioned breathing hole control section. to the atmosphere (of course, some of the air is
7). Therefore, spool 1
6 moves smoothly to the right.

Next, turn off the pilot valve 20,
The supply port 21 is closed, and the output port 22 and discharge port 23 communicate with each other. Therefore, the pressure fluid in the right chamber 12 of the piston 18 is discharged from the outlet 23 through the outlet 22 of the pilot valve 20 through the outlet 24, and the spring 1
9 force moves spool 16 and piston 18 to the right. At the same time, in the above-mentioned breathing hole control section, as the piston 18 moves, atmospheric air is sucked into the left side chamber 12b of the piston 18 through the breathing hole 25, but the check valve 26 is closed and the air is regulated by the variable crest valve 27. Only a minute flow rate of the air is sucked into the left side chamber 12b of the piston 18. Therefore, the piston 18 inside the left chamber 12b of the piston 18
This movement creates a low vacuum state, the rightward movement of the piston 18 slows down, and the spool 16 slowly returns so that the poppet portion 17 seats on the valve seat 15, completing the valve closing and creating the state shown in FIG. It returns to the body.

Conventionally, for example, when the piston 18 moves to the left in FIG. 3, the function of the breathing hole is to drain the air in the left chamber 12b of the piston 18 to the atmosphere so as not to generate back pressure that would hinder the movement of the piston 18. At the same time, when the piston 18 moves to the right, it acts to draw air from the atmosphere into the left side chamber 12b of the piston 18 so as not to create a low vacuum state that would hinder the movement of the piston 18. However, in the present invention, when the piston 18 moves to the right, by actively generating a low vacuum state in the left chamber 12b of the piston 18,
This valve is characterized in that the moving speed of the piston 18 is slowed down to absorb the shock in the main circuit that occurs when the valve is closed.

With the above configuration, the spool movement speed when the valve is closed can be fast at the beginning and slow at the end of closing, which not only makes it possible to absorb the shock in the main circuit that occurs when the valve closes in a short period of time. The moving speed of the spool can also be adjusted by operating the variable stop valve 27, and can be kept constant at all times without being affected by fluctuations in pilot fluid pressure.

In addition, although the above-mentioned embodiment shows the case where it is applied to a two-way valve, it may be applied to a three-way valve or a four-way pilot type switching valve, and the pilot type can be similarly applied to a single or double pilot type switching valve. It's something you get.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view showing a conventional example, FIG. 2 is a circuit explanatory diagram showing a conventional example, and FIG. 3 is a cross-sectional explanatory view of an embodiment according to the present invention. Explanation of symbols, 10... Valve body, 11... Valve seat,
12... Piston chamber, 13, 14... Connection port, 1
5... Valve seat, 16... Spool, 17... Poppet section, 18... Piston, 19... Spring, 20...
... Pilot valve, 21 ... Supply port, 22 ... Output port, 23 ... Discharge port, 24 ... Port, 25 ... Breathing hole, 26 ... Check valve, 27 ... Variable crest valve, 2
8...Breathing hole.

Claims (1)

[Scope of utility model registration request] A valve body having a valve chamber with a main circuit connection opening and a piston chamber following the valve chamber, a spool slidably inserted into the valve chamber, and a piston interlocked with the spool and slidably inserted into the piston chamber. and a pilot valve that is attached to the side of the valve body and supplies and discharges pilot fluid to the piston chamber, and a check valve and a variable crest valve are arranged in parallel in the middle of the breathing hole that opens to the back pressure side of the piston chamber. A pilot type switching valve characterized by being connected to.