JPH0440048Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a closed center type three-position three-port valve.

[Prior Art] A first and second port, an output port, first and second valve seats formed opposite to each other in a flow path that communicates the output port with the first and second ports, and The valve has poppet-shaped first and second valve members biased by a spring in a direction to close the valve seat of the valve member, and a support between these valve members, and the opening/closing operation of the second valve seat by the second valve member is controlled by the second valve member. The 3-port valve, which opens and closes the first valve seat by transmitting the signal to the first valve member using a support, was first opened in 1988.
This is already known from Publication No. 146671.

However, the above-mentioned known 3-port valve is a 2-position valve and cannot cut off communication between the ports, so this valve is used as a vacuum pressure control valve that alternately applies vacuum pressure and air pressure to the suction pad. If you use it, you will waste a lot of air, and
For the same reason, it cannot be used as a mixing valve to mix two fluids or fluids with different temperatures, so there is a demand for an inexpensive closed center type 3-position 3-port valve that can cut off communication between ports. There is.

[Problem to be solved by the invention] The problem to be solved by the invention is to provide an inexpensive closed center type 3-position 3-port valve by simply modifying an existing 2-position 3-port valve. It is in.

[Means for Solving the Problems] In order to solve the above problems, the closed center type 3-position 3-port valve of the present invention has a first port, a second port,
A port, an output port, first and second valve seats formed opposite to each other in a flow path that communicates the output port with the first port and the second port, and a spring in a direction to close these valve seats. A three-port valve comprising a main valve section having biased poppet-shaped first and second valve members, and a pilot section for driving the first and second valve members, the pilot section comprising: A holder is provided that is driven by supplying and discharging pilot fluid to first and second pilot chambers partitioned by a piston, the first valve member is attached to a support pressed by the holder, and the first valve member is attached to a support that is pressed by the holder, A second valve member is slidably installed in the holder via a travel spring, and the holder has an axial length that allows the second valve member to close the second valve seat when the piston is in a neutral position. The support is characterized in that the support has an axial length such that a gap is formed between the piston and the holder at a neutral position of the piston and the holder.

[Operation] When the pilot fluid is supplied to the first pilot chamber, the piston is driven and the holder moves to a position where the support is pressed down, so that the second valve member maintains the closed state of the second valve seat, and 1st
The valve member opens the first valve seat, and the first port and the output port communicate with each other.

When the first pilot chamber is opened to the atmosphere and pilot fluid is supplied to the second pilot chamber, the piston is driven in the opposite direction, and the first valve member closes the first valve seat by releasing the pressure on the support by the holder. At the same time, since the second valve member opens the second valve seat, the second port and the output port communicate with each other.

When both the first and second pilot chambers are opened to the atmosphere, the piston moves to the neutral position and both the first and second valve members close their corresponding valve seats, thereby cutting off communication between the ports.

[Example] Figure 1 shows an example of the present invention, in which the three positions 3
The port valve includes a main valve section 11 and a pilot section 12, and the illustrated example shows a case where this valve is used as a vacuum pressure control valve.

The valve body 14 in the main valve section 11 has a first port 15 connected to a vacuum source 1 such as a vacuum pump,
A first valve seat 18 in a flow path communicating with the first port 15, comprising an output port 16 connected to the suction pad 2 and a second port 17 communicating with the high pressure air source 3 or the atmosphere; The second valve seats 19 in the flow path communicating with the valve body 17 are disposed coaxially and facing away from each other, and the second valve seats 19 in the flow path communicating with the valve body 17
A second valve chamber 24 in which the second valve seat 19 opens between the pilot part main body 21 screwed onto the valve seat 19 side,
A first valve chamber 22 in which the first valve seat 18 opens is formed between the pilot part 21 and a cover 23 screwed on the opposite side, and the output port 16 is connected to the first valve chamber 22.
It communicates with a flow path 25 between the valve chamber 22 and the second valve chamber 24 .

The pilot section main body 21 of the pilot section 12 has a cylinder 29 formed between an intermediate partition wall 27 and a cover 28 screwed to the end, and a piston 30 sliding inside the cylinder 29. It is divided into a first pilot chamber 31 on the cover side and a second pilot chamber 32 on the partition wall side. They each communicate with the second pilot port 34, which was opened in 2013.

The rod 35, which has one end fixed to the piston 30, has a holder 3 at its tip that passes through the partition wall 27 in an airtight manner.
A second valve member 42 that opens and closes the second valve seat 19 is slidably inserted into the holder 36 and moved in the valve closing direction by the biasing force of a travel spring 43. When the second valve member 42 is biased, the stepped portion formed on the periphery of the second valve member 42 engages with the opening edge of the holder 36, thereby preventing the second valve member 42 from jumping out from the holder 36, and the flange on the outer circumference of the holder 36 and the partition wall 2
A second spring 40 that biases the second valve member 42 in a direction to close the second valve seat 19 is compressed between the second valve member 7 and the second valve seat 19 .

On the other hand, the first valve member 38 that opens and closes the first valve seat 18 is urged in the valve-closing direction by a first spring 39 that is compressed between the cover 23 and the first valve member 38 that opens and closes the first valve seat 18. A leg portion of the support 44 extends through the flow path 25 and projects into the second valve chamber 24 . The holder 36 has an axial length that allows the second valve member 42 to close the second valve seat 19 when the piston 30 is in the neutral position, and the support 44 has an axial length that allows the second valve member 42 to close the second valve seat 19.
It has an axial length that creates a slight gap between it and the peripheral flange of the holder 36 in the neutral position.

Next, the operation of the above embodiment will be described.

FIG. 1 shows a state in which the pilot chambers 31 and 32 are both in communication with the outside air and the piston 30 is in the neutral position, and the second valve member 42 is in the neutral position due to the urging force of the travel spring 43 and the second spring 40. The second valve seat 19 is closed, and the first valve member 38 closes the first valve seat 18 by the biasing force of the first spring 39. In this case, since there is a gap between the flange of the holder 36 and the support 44, the valve member 3
There is no problem in closing the valve seats 18 and 19 by the valve seats 8 and 42.

When pilot fluid is supplied to the first pilot chamber 31, the piston 30 is driven downward, and the holder 36 moves to a position where the support 44 is moved downward. Therefore, the second valve member 42 maintains the closed state of the second valve seat 19, and the first valve member 38 opens the first valve seat 18, so that the first port 15 and the output port 16 are connected to the flow path. 25. This allows the output port 16 to connect to the vacuum source 1
Since the vacuum pressure is applied to the suction pad 2 by connecting to the suction pad 2, the suction pad 2 can suction and hold a desired article. In this case, the second valve member 42 is
Since it slides within the holder 36 against the biasing force of the travel spring 43, no overload is applied to the second valve member 42.

When the first pilot chamber 31 is opened to the atmosphere and the pilot fluid is supplied to the second pilot chamber 32,
The piston 30 is driven in the opposite direction and the holder 36
moves upward, the second valve member 42 opens the second valve seat 19, and the first valve member 38 opens the first spring 3.
Since the first valve seat 18 is closed by the urging force of 9, the second port 15 and the output port 16 are connected to the flow path 25.
Compressed air from the air source 3 is supplied to the output port 16 through communication. Therefore, the suction pad 2 releases the suctioned article.

When the pilot fluid in the second pilot chamber 32 is discharged, the second valve member 42 closes the second valve seat 19 due to the biasing force of the second spring 40, and at the same time, the piston 30 and the support 36 It slides to the illustrated neutral position where the biasing force of the travel spring 43 is balanced, and both valve members 38 and 42 close the valve seats 18 and 19, cutting off communication between the ports, so unlike a two-position valve, The amount of air flowing out from the suction pad 2 can be reduced.

In addition, when vacuum pressure is applied to the suction pad 2, if the pilot fluid pressure stops acting due to an accident such as a power outage, the communication between the ports will be cut off, and the suction pad 2 will immediately remove the article. The adsorption retention function will not be lost.

When a self-holding mechanism for self-holding the stroke position of the piston 30 in the pilot section is provided, for example, a permanent magnet is provided on the inner surface of the partition wall 27 and the inner surface of the cover 28 in the pilot section main body 21, and the piston 30 is attracted to it. Alternatively, the cover 28 may be provided with a mechanical detent mechanism or the like for engaging an engaging ball or the like with the piston extension. Thereby, communication between the ports can be maintained even if fluid pressure ceases to act on the pilot chamber.

In the above embodiment, a known 2-position 3-port valve can be made into a 3-position valve by slight modification, so the main parts can be shared with the existing 2-position 3-port valve, so it can be closed. The center type 3-position 3-port valve can be made inexpensive.

In addition, since the three-position valve of the above embodiment can cut off communication between ports at the intermediate position of switching,
By connecting the first and second ports 15 and 17 to different types of fluids or fluids having different temperatures, it is possible to form a mixing valve that mixes these fluids.

[Effects of the invention] According to the invention, an existing 2-position 3-port valve can be made into a 3-position valve by slight modification, so a closed center type 3-position 3-port valve can be made inexpensive. It can be done.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a closed center type three-position three-port valve according to the present invention. 11...Main valve section, 12...Pilot section, 15
...First port, 16... Output port, 17...
2nd port, 18...First valve seat, 19...Second valve seat, 30...Piston, 31...First pilot chamber, 32...Second pilot chamber, 36...Holder, 38...No. 1 valve member, 42... second valve member,
43...Travel spring, 44...Support.

Claims (1)

[Claims for Utility Model Registration] The first port 15, the second port 17, and the output port 16 are formed opposite to each other in a flow path that communicates the output port 16 with the first port 15 and the second port 17. a main valve portion 11 having first and second valve seats 18, 19, poppet-shaped first and second valve members 38, 42 biased by a spring in a direction to close these valve seats; 1. A three-port valve equipped with a pilot section 12 for driving second valve members 38, 42, in which the pilot section 12 is connected to first and second pilot chambers 29, 32 partitioned by a piston 30. Holder 3 driven by supply and discharge of pilot fluid
6, the first valve member 38 is attached to a support 44 pressed by the holder 36, and the second valve member 42 is slidably installed in the holder 36 via a travel spring 43. the holder 36 has an axial length that allows the second valve member 42 to close the second valve seat 19 when the piston 30 is in the neutral position;
6. A closed center type three-position three-port valve, characterized in that the valve has an axial length such that a gap is formed between the valve and the holder 36 at the neutral position of the valve.