JPH0753008Y2 - Direction switching valve - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional control valve used in industrial equipment utilizing fluid pressure.

[0002]

2. Description of the Related Art A pressure fluid supply port, an output port and a discharge port, a valve hole in which these ports are opened, a discharge valve seat formed between the output port and the discharge port of the valve hole, and a slide on the valve hole. A valve rod in which a first seal member that is inserted as much as possible and that cuts off the communication between the supply port and the output port and a poppet-type second seal member that opens and closes the discharge valve seat from the discharge port side are fitted, and the valve rod A directional control valve including a valve portion having pistons attached to both axial ends thereof and a fluid pressure drive portion for exerting a fluid pressure on the piston is already known without particular exemplification. In order to make the stroke of the valve rod constant in this directional control valve, it is necessary that the poppet-shaped second seal member that opens and closes the discharge valve seat seals the discharge valve seat at a fixed position. However, in the above directional control valve, when the fluid pressure of the fluid in the valve portion increases, the poppet-shaped sealing member expands in diameter,
There is a problem that the seal position is likely to change.

[0003]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a directional valve in which a poppet type seal member can seal a discharge valve seat at a substantially constant position regardless of fluctuations in fluid pressure. Especially.

[0004]

In order to solve the above problems, the present invention provides a pressure fluid supply port, an output port and a discharge port, a valve hole in which these ports are open, an output port and a discharge port of the valve hole. A discharge valve seat formed in between, a first seal member that is slidably inserted into the valve hole and that cuts off communication between the supply port and the output port, and a poppet-type first seal member that opens and closes the discharge valve seat from the discharge port side. (2) A directional control valve comprising a valve rod having a seal member fitted therein, a valve portion having pistons attached to both axial ends of the valve rod, and a fluid pressure drive portion for applying a fluid pressure to the piston. The second sea
Of the valve seat and the inwardly sloping surface that constitutes the valve seat sealing surface.
And a cylindrical outer peripheral surface of the axially outward of, the piston of the discharge port side, substantially all of the outer peripheral surface of the second seal member
A pressing portion that covers the surface and prevents the diameter expansion, and a second sealing portion
Ventilation that connects the contact part between the material and the piston to the discharge port
It is characterized by having a hole .

[0005]

The outer peripheral surface of the second seal member covers substantially the entire surface thereof.
Since it is pressed by the pressing part of the piston on the discharge side, the seat of the valve seat
Diameter does not increase due to fluid pressure acting on the seal or the sealing member.
Therefore, the valve seat seal may be repeated and the fluid pressure may fluctuate.
Also, the sealing position of the discharge valve seat of the second sealing member is constant. Repeated opening and closing of the exhaust valve seat by the second seal member
Fluid flowing into the contact part between the second member and the piston due to
Is discharged to the discharge port through the ventilation hole provided in the piston.
As a result, the fluid pressure flowing into the abutting part causes
And the second seal member is pushed out from the pressing portion of the piston.
Since this will not happen, the discharge of the second seal member
The seal position of the valve seat can be made constant.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an embodiment of the present invention, in which this directional control valve comprises a valve portion 1 and a pilot valve 2 constituting a fluid pressure operating portion. The valve unit 1 includes a valve body 4 and end plates 5 and 6 on both sides in the axial direction thereof. The valve body 4 has a pressure fluid supply port P, output ports A and B, and a discharge port E.
A, EB, and an axial valve hole 7 in which these ports open are formed, and discharge valve seats 8, 8 are formed between the output ports A, B and the discharge ports EA, EB in the valve hole 7. . Further, sleeves 9a and 9b are fitted between the end plates 5 and 6 and both ends of the valve hole 7, and the inner diameter of the sleeve 9b is made smaller than the inner diameter of the sleeve 9a. The sleeves 9a and 9b are hermetically sealed. Sliding pistons 10 and 1
1 is attached to both ends of a valve rod 12 that slides in a valve hole 7 so as to be integrally slidable by attaching bolts, and is provided between the end plates 5 and 6 and the pistons 10 and 11 and pressure chambers 13 and 14 respectively.
Is formed.

The valve rod 12 includes a valve rod main body 16, a spacer 17 fitted in a central portion of the main body 16 in the axial direction, and a spool-shaped first seal member 1 sequentially fitted on both sides thereof.
8 and 18, seal member pressing rings 19 and 19, and poppet-shaped second seal members 20 and 20. These seal members are made of an elastic material such as synthetic rubber. The first seal members 18 and 18 are provided to disconnect the communication between the ports P and A and P and B by sliding the valve rod 12, and to open and close the discharge valve seats 8 and 2.
0 and 20 are inwardly inclined toward the center of the valve stem body 16.
Valve seat sealing surfaces 20a, 20a
It has a cylindrical outer peripheral surface 20b, 20b. Also,
The pistons 10 and 11 are provided with second seal members 20, 2
No. 0 outer peripheral surfaces 20b, 20b are pressed to substantially the entire surface of the outer peripheral surface 20b, 20b to prevent expansion of the diameter, and vent holes 10b ...
And 11b ... This vent hole 10b, ...
. And 11b ... together with the grooves on the side surfaces of the second seal members 20, 20 as well as the second seal members 20, 20 and the piston 10,
The air is prevented from being contained in the contact portion with 11 .

On the other hand, in the pilot valve 2 as a fluid pressure drive unit, the pilot inlet port 23 and the pilot outlet port 24 are communicated with each other by exciting the solenoid 2a, and the pilot outlet port 24 is released by deenergizing the solenoid 2a.
The pilot inlet port 23 is configured as a well-known 3-port solenoid valve that communicates with the pilot exhaust port 25. The pilot inlet port 23 is connected to the pressure accumulating chamber 27 that communicates with the supply port P by the passage 26, and the pilot outlet port 24 is connected to the pressure chamber 13. The pilot exhaust port 25 communicates with the exhaust port E formed in the end plate 5, and the pressure chamber 14 communicates with the pressure accumulating chamber 27 by a passage 28. Reference numeral 30 in the figure,
Reference numeral 30 is a guide ring for the pistons 10 and 11.

In the above embodiment, when the solenoid 2a of the pilot valve 2 is deenergized, the pressure chamber 14 is supplied with fluid from the pressure accumulating chamber 27 and the fluid in the pressure chamber 13 is discharged from the exhaust port E. Piston 1
0 and 11 and the valve rod 12 move to the left in the figure, and the port P
And B and A and EA communicate with each other, and communication between ports P and A and B and EB is blocked (see the upper half of the valve rod 12). When the solenoid 2a is excited, the pilot fluid pressure supplied to the pressure chamber 13 causes the pistons 10, 1
1 and the valve rod 12 are moved to the right in the figure, the ports P and A and the ports B and EB are communicated with each other, and the ports P and B and the ports A and EA are blocked (also see the lower half). Due to the reciprocating movement of the valve rod 12, the fluid pressure of the fluid flowing between the ports P and A and between the ports P and B acts in the direction of expanding the diameter of the second seal members 20, 20.
Has a cylindrical outer peripheral surface 20b, 20b having pistons 10, 1
Pressing portion 10a provided on the 1, because it is more pressing in 11a
Moreover , the diameter expansion is prevented. Therefore, even if the fluid pressure of the fluid flowing through the valve portion 1 changes, the second seal members 20, 20
Can seal the discharge valve seats 8, 8 in a fixed position. In addition, the second seal member 20, 20,
By repeatedly opening and closing the valve seats 8, 8, the second seal part
At the contact part between the materials 20, 20 and the pistons 10, 11, air is
The inflowing air is provided to the pistons 10 and 11
Through vent holes 10b, ... And 11b ,.
Is discharged to the contact parts EA and EB and flows to the contact part.
The second seal members 20 and 20 are moved by the fluid pressure that has entered.
It will not be pushed out from the holding parts 10a, 11a.
Therefore, also by this, the discharge by the second seal members 20, 20
The sealing positions of the valve seats 8 and 8 can be made constant.

The directional control valve of the present invention is not limited to the 5-port valve, and the fluid pressure drive unit is not limited to the pilot valve.

[0011]

According to the directional control valve of the present invention, the poppet type second seal member for opening and closing the discharge valve seat is prevented from expanding in diameter by the holding portion provided on the discharge side piston, so that the valve seat seal is prevented.
Even if the valve is repeatedly used or the fluid pressure fluctuates , the discharge valve seat can be always sealed at the same position, so that the stroke of the valve rod can be made constant. Also, the second member and the piston
The fluid flowing into the abutment part of the
The contact part is discharged through the discharge port.
The second seal member moves to the piston due to the fluid pressure flowing into the
Since it is not pushed out from the presser section, this
Also makes the sealing position of the discharge valve seat constant by the second sealing member
can do.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an example.

[Explanation of symbols]

1 valve part, 2 pilot valve, 7 valve hole, 8 discharge valve seat, 10 and 11 piston, 10a and 11a retainer part, 12 valve rod, 18 1st seal member, 20
Second seal member, P supply port, A, B output port, EA, EB discharge port.

Claims (1)

[Scope of utility model registration request] 1. A pressure fluid supply port, an output port and a discharge port, a valve hole in which these ports are opened, a discharge valve seat formed between the output port and the discharge port of the valve hole, and a slide on the valve hole. A valve rod in which a first seal member that is inserted as much as possible and that cuts off the communication between the supply port and the output port and a poppet-type second seal member that opens and closes the discharge valve seat from the discharge port side are fitted, and the valve rod In a directional control valve including a valve portion having pistons attached to both axial ends of the valve and a fluid pressure drive portion for applying a fluid pressure to the piston, the second seal member is a valve seat sealing surface. direction
And a cylindrical outer peripheral surface axially outward thereof, wherein the piston on the discharge port side covers substantially the entire outer peripheral surface of the second seal member and prevents expansion of its diameter. ,
Connect the contact portion between the second seal member and the piston to the discharge port.
A directional control valve, characterized in that it has a vent hole for passage.