JPH0210324Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a residual pressure release device mainly used when driving a fluid pressure cylinder with a closed center type three-position switching valve.

[Prior Art] Normally, when a workpiece is driven by a fluid pressure cylinder, the capacity of the cylinder is set to be large in order to move the workpiece smoothly without causing any movement delay. When the workpiece gets caught in the middle of the stroke, a large force of [piston diameter x set pressure] is acting on the cylinder, so as soon as the workpiece is removed, the cylinder suddenly pops out. There is a high risk of personal injury.

In particular, when using a closed center type 3-position switching valve, when pressure is sealed in the rod and head sides of the cylinder in the neutral position, the workpiece that is caught in that state may be removed. Difficult to remove.

If the work gets caught in this way,
It is necessary to release the residual pressure inside the cylinder in some way to safely remove the workpiece from being caught, without causing the cylinder to pop out, or by allowing the cylinder to move freely.

Conventionally, as a means for releasing the residual pressure, an independent switching valve a for releasing the residual pressure is used, as shown in FIG. However, in order to release the residual pressure in the cylinder due to a work being caught, etc., normally the directional control valve b is switched to the neutral position, and then the directional control valve for releasing the residual pressure is installed. Although there are many cases in which urgent action is required to switch the switch a, the operation takes time and requires complicated operations, and the same complicated operations are required when returning.

[Problems to be solved by the invention] In the event of an abnormality such as a work being caught, the present invention can eliminate the remaining cylinder by simply stopping the supply of pressure fluid to the supply port and opening the port to the atmosphere. The problem to be solved is to be able to release the pressure and return the residual pressure release mechanism to its original state simply by restarting the supply of pressure fluid to the supply port. be.

[Means for Solving the Problems] In order to achieve the above object, the residual pressure release device of the present invention includes a base equipped with a fluid supply port, two output ports, and two discharge ports, and a Equipped with a spacer that is placed between the directional control valve that switches the direction of fluid flow,
This spacer is provided with a supply communication hole, first and second output communication holes, and first and second discharge communication holes, which communicate with the supply port, output port, and discharge port, respectively. First and second residual pressure release holes are provided to communicate the output communication hole of the spacer with the atmosphere, and a spool is slidably inserted into the sliding hole provided in the spacer. At the same time, a piston equipped with a poppet valve element for opening and closing the second residual pressure release hole is installed at the other end of the spool. A technical means is provided in which the pressure receiving chamber is communicated with the supply communication hole, and the spool is urged by a return spring in the direction of opening the residual pressure release hole against the fluid pressure acting on the piston in the pressure receiving chamber. We are hiring.

[Function] Under normal conditions, fluid from the supply port flows into the pressure receiving chamber and acts on the piston to drive the piston and spool, so the poppet valve bodies provided therein reduce the first and second residual pressures. The open passage is closed. Therefore, the output port and the atmosphere are not communicated with each other, and the cylinder connected to the output port operates normally.

When the fluid pressure to the supply port is removed in an abnormal situation where the work is caught, the fluid pressure in the pressure receiving chamber decreases, so the piston and spool act on the biasing force of the return spring and each poppet valve body. The pressure is restored by the combined force with the fluid pressure from the output port, and the first and second residual pressure release holes are opened and communicated with the atmosphere. Therefore, the residual pressure in the head chamber and rod chamber of the cylinder is automatically discharged, making it possible to freely move the cylinder and remove the workpiece from getting caught.

In addition, simply by restarting the supply of pressure fluid to the supply port, the poppet valve body closes the first and second residual pressure release holes, and the residual pressure release mechanism returns to its original state. The cylinder connected to the port immediately operates normally.

[Effects of the invention] With the residual pressure release device of the present invention, in the event of an abnormality such as a work being caught, the system can simply stop the supply of pressure fluid to the supply port and open the port to the atmosphere.
By simply releasing the residual pressure in the cylinder and restarting the supply of pressure fluid to the above supply port,
The residual pressure release mechanism can be returned to its original state, and therefore the operation of releasing and returning the residual pressure can be easily performed in a short time.

In addition, the valve body that opens and closes the residual pressure release hole has a poppet structure, and its return force is obtained as a composite force of the urging force of the return spring and the fluid pressure from the output port acting on each poppet valve body. Therefore, it is possible to eliminate malfunctions caused by sticking of the valve body and ensure reliable operation.

Furthermore, in the present invention, the residual pressure release mechanism is configured as a separate entity from the valve body, so the residual pressure can be released by simply removing the supply pressure, regardless of the operating state of the valve body. This can be done automatically with a simple operation, and even if the spool becomes stuck or malfunctions, the residual pressure can be reliably released, and the residual pressure release mechanism is easy to maintain, replace, etc. , the safety of driving the fluid pressure cylinder can be increased.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings. The switching valve 1 shown in FIG. 2 consists of a base 2, a valve body 3, and a residual pressure release device 4 provided between them.

The base 2 has a fluid supply port 5, first and second output ports 6a, 6b connected to the head chamber and rod chamber of the cylinder, and first and second discharge ports 7a, 7b. , a supply hole 8 communicating with each of these ports, first and second output holes 9a, 9b, and first and second discharge holes 10.
a, 10b.

The valve body 3 also includes a supply hole 11 communicating with each hole of the base 2, first and second output holes 12a, 12b, and first and second discharge holes 13.
A sleeve 15 is disposed within the body 14 having the sleeves a and 13b.
A spool valve 16 is installed inside this sleeve 15.
The spool valve 16 is slidably inserted into the spool valve 16, and the spool valve 16 is driven by an appropriate operating means 17 to switch the flow direction of the fluid between the respective through holes.

Further, as is clear from FIG. 3, the residual pressure release device 4 has a supply communication hole 19, a first and a second supply communication hole 19, which connects the respective communication holes between the base 2 and the valve body 3. Output communication hole 20a, 2
0b, first and second discharge communication holes 21a, 21b
Attach the spacer 18 with
A spool 23 is movably inserted into a sliding hole 22 provided at 8 through a seal member 24, and a piston 25 that partitions a pressure receiving chamber 26 and a valve chamber 27 is fixedly attached to one end of the spool 23. , the piston 2
A first residual pressure release hole 29 is provided on the valve chamber 27 side of the valve chamber 5.
A poppet valve body 28 is attached to open and close the
A poppet valve body 30 for opening and closing the second residual pressure release hole 31 is attached to the other end of the spool 23.

The first residual pressure release hole 29 communicates the first output communication hole 20a with the atmosphere through the valve chamber 27 and a hole 32 provided in its side wall, and includes a valve seat facing the valve chamber 27. ing.

On the other hand, the second residual pressure release hole 31 is connected to the spacer 1
8 is connected to an orifice 33a on the valve seat body 33 fitted to the end of the valve seat body 33. The valve seat body 33 is fitted into an enlarged hole formed at an extension position of the sliding hole 22 of the spool 23 at the end of the spacer 18 via a sealing member, whereby the valve chamber 34 is inserted into the enlarged hole. The second residual pressure release hole 3
1 and has an orifice 33a that opens into the valve chamber 34, and the push rods 43, 43 of the manual return means 42, which will be described later, are inserted into the valve seat body 33 at a position that does not interfere with the orifice 33a. A hole is formed. In addition, the valve chamber 34
is open to the atmosphere through a through hole 35 provided in its side wall.

These valve seats 29a and orifices 33a are
When the spool 23 moves in the axial direction, the movement is relatively rapid, so the poppet valve body 2
8 and 30 are opened and closed almost simultaneously.

In order to ensure that the valve seat 29a and the orifice 33a can be opened and closed by the two poppet valve bodies described above, the poppet valve body 30 is provided with a hole that penetrates through the valve seat 29a and the orifice 33a, as is clear from FIGS. With both ends of the pin 36 fitted into the elongated hole 37 of the spool 23, the pin 36 is movably inserted into the valve hole 38 of the spool 23, and the bias spring 39 is inserted into the valve hole 38 of the spool 23.
is biased toward the orifice 33a. Therefore, even if there is a slight difference in the opening and closing strokes of the two poppet valve bodies 28 and 30, this difference is absorbed by the poppet valve body 30 moving back and forth within the range of the elongated hole 37.

Further, in order to drive the spool via the piston 25, the pressure receiving chamber 26 is communicated with the supply communication hole 19 through the through hole 40, and the piston 25
A return spring 41 is disposed between the valve chamber 27 and the side wall of the valve chamber 27, and the return spring 41 urges the piston 25 and the spool 23 in the direction of opening the valve seat 29a and the orifice 33a. As a result, the piston 25 and spool 23 are moved to the right by the fluid pressure flowing into the pressure receiving chamber 26 when fluid pressure is acting on the supply port 5, and the two poppet valve bodies 28 and 30 are moved to the right. Valve seat 29a and orifice 33a are closed. When the fluid pressure in the supply port 5 is removed, it returns to the position shown in _FIG .
The force acting on the poppet valve bodies 28, 30 due to the fluid pressure from the output communication holes 20a, 20b.
This is the combined force of F ₂ and F ₃ , and together with the fact that the valve bodies 28 and 30 have a poppet structure, it is possible to ensure their return.

Here, F ₂ = (d ₁ ² - d ₂ ² ) x 0.785 x ps F ₃ = d ₃ ² x 0.785 x ps - f ₄ However, ps: Secondary fluid pressure d ₁ : Seat of poppet valve body 28 Part diameter d ₂ : Shaft diameter of spool 23 d ₃ : Diameter of orifice 33a f ₄ : Biasing force of bias spring 39.

As described above, the return performance of the spool 23 is very high, but in consideration of the case where it does not return due to some reason, the spacer 18 is equipped with a manual return means 42 that can manually return the spool 23. It is attached. That is, the push rod 43 is slidably inserted into the valve seat body 33 at a position where it does not interfere with the orifice 33a, and the tip of the push rod 43 is inserted into the spool 2.
A pressing member 45 facing the end surface of 3 and exposed to the outside through the end cover 44 at its rear end.
is attached, and a manual spring 46 urges this push rod 43 to a retracted position with respect to the spool 23. Therefore, if the push rod 43 is moved forward via the push member 45 in the state shown in FIG.
3 can be returned to the position shown in FIG.

In the above embodiment, the first residual pressure release hole 29 is formed by providing a small-diameter stepped portion around the spool 23. Therefore, the sealing member 24 is required and the resulting sliding resistance is However, in the embodiment shown in FIG. 6, a first residual pressure release hole 29 is formed in the spacer 18, and a poppet valve body 2 is used to open and close the first residual pressure release hole 29.
8' has a double seal structure consisting of an inner seal member 47a and an outer seal member 47b. Therefore, the sealing member 2 as described above is attached to the spool 23.
4 is not necessary, and the accompanying sliding resistance can be eliminated and the return performance can be further improved.

Note that the return force F of the spool 23 in this embodiment is F=F ₁ +F ₃ +F ₄ . However, F ₁ and F ₃ are the same as in the first embodiment, and the force F ₄ acting on the poppet valve body 28' is F ₄ = (d ₄ ² - d ₅ ² ) x 0.785 x ps d ₄ : Diameter of the outer seal member 47b _d5 : Diameter of the inner seal member 47a.

7A and 7B show symbolically the connection state when the cylinder 48 is driven by the switching valve 1, and FIG. 7A shows the valve body 3 of the switching valve 1 as a symbol. When a position type is used, B corresponds to the switching valve shown in FIG. 2 when a three position type is used.

[Brief explanation of drawings]

Fig. 1 is a connection diagram of a conventional example, Fig. 2 is a sectional view showing an embodiment of the present invention, Fig. 3 is a plan view of the residual pressure release device, and Figs. 4 and 5 are main parts with different switching positions. FIG. 6 is an enlarged sectional view showing different embodiments of the present invention, and FIGS. 7A and 7B are connection diagrams of the present invention in use. DESCRIPTION OF SYMBOLS 1...Switching valve, 2...Base, 3...Valve body, 5...Supply port, 6a, 6b...Output port, 7a, 7b...Discharge port, 16...Spool valve, 17...Operation means , 18...Spacer, 1
9...Supply communication hole, 20a, 20b...Output communication hole, 21a, 21b...Discharge communication hole, 22...Sliding hole, 23...Spool, 25...Piston, 2
6... Pressure receiving chamber, 28, 30... Poppet valve body, 2
9, 31... Residual pressure release hole, 41... Return spring.

Claims (1)

[Scope of utility model registration request] A spacer is provided between a base having a fluid supply port, two output ports, and two discharge ports, and a directional switching valve that switches the direction of fluid flow between the ports. The spacer has first and second supply communication holes that communicate with the supply port, output port, and discharge port, respectively.
an output communication hole, and first and second exhaust communication holes, as well as first and second residual pressure release holes that communicate the first and second output communication holes with the atmosphere;
A spool is slidably inserted into a sliding hole provided in the spacer, and a piston equipped with a poppet valve element for opening and closing the first residual pressure release hole is attached to one end of the spool. At the other end of
A poppet valve body for opening and closing the second residual pressure release hole is provided, a pressure receiving chamber partitioned by the piston is communicated with the supply communication hole, and the fluid pressure acting on the piston is resisted in the pressure receiving chamber, A residual pressure release device for a directional switching valve, characterized in that the spool is biased by a return spring in the direction of opening the residual pressure release hole.