JPH0442611Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is suitable for driving fluid pressure cylinders, etc.
This relates to a three-port valve.

[Prior Art] Conventionally, first and second valve seats between a first port (output port) and second and third ports (supply and discharge ports) are provided opposite to each other, and these valve seats are arranged opposite to each other. Behind the first and second valve bodies that open and close the seats, first and second springs that bias these valve bodies toward their respective valve seats are installed, and the first and second valve seats are compressed. The opening/closing mechanism for individually opening the valve body includes a rod on which first and second valve bodies are slidably mounted, and first and second locking shoulders that individually engage both valve bodies on the rod. A three-position, three-port valve having the following is known, for example, from Japanese Patent Publication No. 15880/1983.

However, the above-mentioned known valve has a problem in that it lacks consideration for blow-through between ports.

That is, when the first and second valve bodies open their valve seats due to fluctuations in fluid pressure or the like while the first and second valve bodies are being driven,
Creates an atrium where the supply port and discharge port communicate directly. This blow-through poses a problem in terms of energy conservation when a large valve is used to drive an actuator because the flow rate of pressure fluid is large.

In order to prevent the blow-through between the ports, for example, the biasing force of the first and second springs may be increased to increase the return speed of the valve body, or the time required for the locking shoulder to lock onto the valve body may be increased. It is possible to increase the play stroke, but the former increases the driving force of the rod, and the latter increases the stroke of the rod and increases the size of the valve, so neither is preferable.

[Problems to be Solved by the Invention] A technical problem to be solved by the invention is to reliably prevent blow-through between ports in a three-position port valve.

[Means for Solving the Problems] In order to solve the above problems, the three-position three-port valve of the present invention has the first and second valve seats between the pressure fluid output port and the supply and discharge ports facing away from each other. A 3-port valve in which the valve seats are opened and closed by the first and second valve bodies, respectively.
First and second back chambers having approximately the same diameter as the first and second valve seats are defined behind the first and second valve bodies, respectively, by pressure equalizing holes bored in both the valve bodies. In addition to communicating with the output port, a first
and an opening/closing mechanism that compresses first and second springs that bias the second valve body toward their respective valve seats, and closes the first and second valve seats together and opens them individually. A piston driven by fluid pressure, a rod on which the first and second valve bodies are slidably mounted, and first and second locking shoulders that individually lock on both the valve bodies on the rod. It is configured as having the following.

[Function] When the piston and its rod are at rest, the first and second pistons, which are slidably attached to the rod,
The valve body closes the valve seat by the biasing forces of the first and second springs. In this case, since the fluid pressures acting on both sides of the first and second valve bodies are balanced by the pressure equalizing holes, the first and second valve bodies can securely hold the valve seat regardless of the fluid pressure at the port. Close.

When the piston and rod are actuated by pilot fluid pressure, one locking shoulder on the rod causes one valve body to open the valve seat and the other valve body to close the valve seat. Also, when the piston and rod are driven in opposite directions, the other valve body opens the valve seat due to the other locking shoulder. Therefore, the three-port valve can take three positions.

In this case, the driving force of the piston is
Since the fluid pressure acting on both sides of the valve body is balanced by the pressure equalizing hole, it can be made small enough to compress the spring, and the first and second valve bodies have pressure equalization on both sides. Since the acting fluid pressure is balanced, the biasing force of the closing spring quickly closes the first and second valve seats regardless of fluctuations in fluid pressure, so the biasing force of the closing spring can be increased. Blow-through between the supply port and the discharge port can be reliably prevented without increasing the driving force of the rod.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

In the embodiment shown in FIG. 1, the valve body 1 is provided with a pressure fluid supply port 3, an output port 2 and a discharge port 4, with a valve connecting them between the output port 2 and the supply and discharge ports 3, 4. 1st and 2nd
Valve seats 5a and 5b are formed on the same axis in a back-to-back state, and can be opened and closed by first and second valve bodies 6a and 6b, respectively.

The first valve body 6a includes a valve part 7a that opens and closes the first valve seat 5a, and a cylindrical part 8a whose sliding movement in the axial direction is guided by the guide cylinder part 9a of the valve body 1,
A pressure equalizing hole 12a is formed in the first valve body 6a with a first back chamber 11a defined behind the first valve body 6a.
The valve element 6a is communicated with the output port 2 to balance the fluid pressures acting on both sides of the valve element 6a. Furthermore, a first spring 1 is installed in the first back chamber 11a.
3a is compressed, and this spring 13a urges the first valve body 6a toward the first valve seat 5a.

Further, the second valve body 6b is connected to the first valve body 6a.
It has a valve part 7b and a cylindrical part 8b, and communicates the second back chamber 11b behind it with the output port 2 through the pressure equalizing hole 12b in the valve body 6b. It is biased toward the second valve seat 5b by a second spring 13b contracted therein. In addition, in the figure, 9b indicates a guide cylinder part.

The opening/closing mechanism for opening and closing the first and second valve bodies 6a and 6b includes a piston 21 that is slidably inserted in the valve body 1 in the axial direction, and a first valve body that is partitioned on both sides of the piston 21. and second pilot room 22
a, 22b are pilot solenoid valves 23a, 23b.
This allows communication between an air source (not shown) and the atmosphere to be independently switched between the pilot chamber 22 and the atmosphere.
The piston 21 is configured to be able to be driven in the axial direction by supplying and discharging the pilot fluid in the pistons a and 22b. Rod 24 integrally fixed to the piston 21
are the first adapter 25a in the valve body 1, the first
and second valve bodies 6a, 6b and second adapter 25b
A sleeve 26 is fitted and fixed to the portion sandwiched between the first and second valve bodies 6a and 6b, and the first and second valve bodies are fitted to both ends of the sleeve 26 so as to be slidable in the axial direction. First and second locking shoulders 27a, 27b are formed to lock onto the second valve bodies 6a, 6b individually. In addition, in the figure, 28a and 28b indicate bearings.

In the 3-port valve configured as described above, the first and second ports are controlled by a pair of pilot solenoid valves 23a and 23b
When both the pilot chambers 22a and 22b are evacuated, as shown in FIG. Second
The valve seats 5a, 5b are closed together by the first and second valve bodies 6a, 6b urged by their springs 13a, 13b. In this case, the first and second valve bodies 6
The fluid pressure acting on both sides of a and 6b is equalized by the pressure equalizing hole 12.
a, 12b, the first and second valve bodies 6a, 6b are biased by the biasing forces of the first and second springs 13a, 13b, regardless of the fluid pressure of the output port 2. The first and second valve seats 5a and 5b are securely closed.

In this state, if the pilot fluid is supplied only to the first pilot chamber 22a by one of the solenoid valves 23a, the piston 21 moves downward as shown in the figure, so that the second valve latched to the second latching shoulder 27b While the body 6b compresses the second spring 13b, the second valve seat 5
Open b. At this time, the rod 24 freely slides relative to the first valve body 6a, and therefore the first valve body 6a
a is the first valve seat 5 due to the biasing force of the first spring 13a.
a is kept closed. Contrary to the above,
If the pilot fluid is supplied only to the second pilot chamber 22b, the first valve body 6a, which is locked to the first locking shoulder 27a on the rod 24, moves upward while compressing the first spring 13a, and the first valve seat Only 5a is opened.
Therefore, the three-port valve can take three positions.

In the three-port valve shown in FIG. 1, since the valve body is in a pressure-balanced state, there are no restrictions on the direction of fluid flow or the level of pressure between the ports.

Therefore, the first and second valve bodies 6a, 6b are
The first and second valve seats 5a, 6a are quickly moved by the small biasing forces of the first and second springs 13a, 13b.
Since the ports 3 and 4 are closed to prevent blow-through between the ports 3 and 4, there is no need to increase the urging force of the springs 13a and 13b or the stroke of the rod 24.

FIG. 2 is for showing an example of the above-mentioned driving style, 61 is a double-acting actuator, 62 and 63 are the above-mentioned 3-port valves, 64 and 65 are air sources, and the outputs of the 3-port valves 62 and 63 are shown in FIG. port 62
a, 63a are communicated with the rod chamber 66 and head chamber 67 of the double-acting actuator 61, and the second port 6
2b, 63b are opened to the atmosphere, and third port valves 62c, 63c are communicated with air sources 64, 65. Both the 3-port valves 62 and 63 can each take three positions, so there are 9 positions in total.
The standard driving mode is realized. The number of driving modes is such that, for example, the pressures of the pair of air sources 64 and 65 are different or one is dependent on the other, or the exhaust port pressures of a pair of 3-port valves are different or one is dependent on the other. By setting the number of driving modes to be 9, the amount of change X can be increased to 9.

[Effects of the invention] The 3-port valve of the present invention has a mechanism for opening and closing a pair of valve bodies, which consists of a piston driven by pilot fluid pressure, a rod on which the pair of valve bodies are slidably mounted, and a piston on the rod. The first valve is individually engaged with both valve bodies of the
and a second locking shoulder, the pair of valve elements can take three positions: a position where the valve seats are both closed, and a position where the valve seats are individually opened.

In addition, since the fluid pressure acting on both sides of the pair of valve bodies is equal, the first and second valve bodies quickly and reliably close the valve seat by the biasing force of the spring, regardless of the magnitude of the fluid pressure. , it is possible to prevent blow-through between the supply port and the discharge port, and the driving force of the valve body can be reduced.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a configuration diagram showing an example of a double-acting actuator drive circuit using them, and Fig. 3 is an example of an actuator drive circuit using a conventional 3-port valve. FIG. 2, 62a, 63a...output port, 3, 62
b, 63b...supply port, 4, 62c, 63c
...Exhaust port, 5a...First valve seat, 5b...Second valve seat, 6a...First valve body, 6b...Second valve body,
11a...first back chamber, 11b...second back chamber, 12
a, 12b... pressure equalization hole, 13a... first spring, 1
3b...Second spring.

Claims (1)

[Scope of utility model registration request] A three-port device in which first and second valve seats between a pressure fluid output port and a supply and discharge port are provided opposite to each other, and these valve seats are opened and closed by the first and second valve bodies, respectively. In the valve, first and second back chambers having substantially the same diameter as the first and second valve seats, which are defined behind the first and second valve bodies, are provided in pressure equalizing holes bored in both the valve bodies. Therefore, first and second springs that communicate with the output ports and urge the first and second valve bodies toward their respective valve seats are compressed in their back chambers, and the first and second springs are connected to the output ports. An opening/closing mechanism for closing the valve seats together and opening them individually,
A piston driven by pilot fluid pressure, a rod on which the first and second valve bodies are slidably mounted, and first and second locks that individually engage both valve bodies on the rod. A 3-position 3-port valve characterized by having a shoulder.