JPS6324165B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a hydraulic actuator that is installed together with a flow control valve in the circuit of a hydraulic actuator used in a feeding device for movable parts such as slide tables in machine tools. This invention relates to a mechanically operated shut-off valve that controls the feed rate of a section.

[Prior art and its problems]

This type of mechanically operated shut-off valve has traditionally been
For example, it has been proposed in Japanese Utility Model Publication No. 37-485 and Japanese Patent Publication No. 30528-1982.

However, in the shutter-off valve proposed in Publication No. 37-485, the valve element is a pilot valve and is mechanically operated and moved by a cam plate installed on a movable part such as a slide table. It is small in size, and by opening and closing the pilot passage with the same valve body, the poppet can be opened and closed via the piston and rod to open and close the main passage. need to be larger),
Even if the liquid supplied to the hydraulic actuator (hydraulic cylinder) is at a high pressure and large flow rate, there is no need to increase the size of the pilot valve body by simply enlarging the main passage, the poppet, and the piston that opposes it. The spring force that returns the valve body to its original position may be small. Therefore, the pushing up force (reaction force) acting on the movable parts such as the slide table can be reduced, and the machining accuracy of the machine tool can be improved. However, the pilot passage adopted in the shut-off valve of the same publication is connected to the oil tank by a conduit pipe, although it is branched from the middle part of the main passage provided in the valve body, so the space required for piping is secured. Not only is this necessary, but the cost increase required for piping is unavoidable. In addition, in the shut-off valve of the same publication, the poppet has the function of a check valve, so it is possible to quickly return the movable parts such as the slide table without installing a separate large check valve. In this shut-off valve, it is necessary to dispose a piston larger than the poppet in opposition to the poppet, so it is not possible to reduce the size of the valve.

On the other hand, the shut-off valve proposed in Japanese Patent Publication No. 54-30528 does not have a pilot valve, so although the problem caused by connecting the pilot passage to the oil tank via a conduit pipe does not occur, the slide table A valve body that is mechanically operated and moved by a cam plate installed on a movable part is configured to directly shut off all liquid flowing within the shut-off valve, and the liquid is at a high pressure and large flow rate. In such cases, the valve body must be made larger. However, when the valve body is enlarged, the spring force for returning the valve body to its original position becomes large, and a large mechanical operating force is required. In this case, the movable parts such as the slide table are pushed and moved by a large reaction force, resulting in a decrease in the machining accuracy of the machine tool.
In addition, in this shut-off valve, when the valve body is mechanically operated and moved, the valve body blocks not only the flow of liquid to one side but also the flow to the other side, so movable parts such as the slide table etc. If it is necessary to return the liquid quickly, a large check valve that allows free flow of liquid in the other direction must be provided in parallel to the valve body, making the valve large.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and the mechanically operated shut-off valve has two ports through which liquid flows in and out, a main passage connecting these two ports, and a middle part of the main passage. A valve body having a pilot passage that branches and connects to one port, the valve body being movably inserted into a branch part of the main passage and the pilot passage in the valve body, and seated on an annular valve seat provided in the main passage. The main passage is closed by a spring force when liquid does not flow toward the pilot passage through a small hole that constantly communicates the pilot passage with the other port. a poppet that moves against a spring force to open the main passage when liquid flows through the small hole toward the pilot passage; a valve body that is movably fitted into the pilot passage in the valve body; When the robot is moved by a mechanical operation received from a movable part such as the slide table, the pilot passage is closed, and when the mechanical operation is released, the pilot passage is returned to its original position by a spring force. an annular valve having a pilot valve that opens and is exposed to liquid supplied to said one port even when said poppet closes said main passage and is subjected to hydraulic pressure against a spring force acting on said poppet; A pressure receiving surface is formed on the poppet, and a check valve is provided in the pilot passage to prevent flow from the one port to the small hole through the pilot passage. be.

[Action of the invention]

In the shutoff valve according to the present invention, when one port is connected to the tank and liquid from the hydraulic actuator flows into the other port, when the pilot valve is open, the liquid directs the small hole toward the pilot passage. Because of the flow, the poppet moves against the spring force to open the main passage, through which the liquid flows freely from the other port to the one port, resulting in rapid forward movement by the hydraulic actuator. . Furthermore, when the pilot valve is closed by mechanical operation in such a state, the liquid no longer flows through the small hole toward the pilot passage, so that the poppet closes the main passage by the spring force. Therefore, at this time, liquid does not flow from the other port to the one port through the main passage, and the flow rate control valve provides a slow feed operation by the hydraulic actuator. On the other hand, if one port is connected to a pressure source and liquid is supplied to a hydraulic actuator from the other port, the check valve installed in the pilot passage will prevent the liquid from flowing regardless of whether the pilot valve is open or closed. The flow to the small hole is blocked, and the poppet receives liquid pressure from the pressure source supplied to one port on its annular pressure receiving surface and moves against the spring force to open the main passage. Liquid flows in free flow from one port to the other through the passageway, providing quick return action by the hydraulic actuator.

〔Effect of the invention〕

In the shut-off valve according to the present invention, each of the above-mentioned operations can be achieved by the valve body, poppet, pilot valve, and check valve, and even if the liquid flowing through the main passage has a high pressure and a large flow rate, the valve body of the pilot valve By keeping the check valve small and enlarging the main passage and poppet, optimum control of the liquid can be achieved. Therefore,
According to this shut-off valve, in any case, the shut-off valve can be operated with a small mechanical operating force that resists the weak spring force of the return spring that urges the small valve body to its original position. As a result, the reaction force acting on movable parts such as the slide table can be reduced, and the machining accuracy of the machine tool can be improved.

Furthermore, in the shutoff valve according to the present invention, even when the poppet closes the main passage, the annular pressure receiving surface is exposed to the liquid supplied to one port and receives the liquid pressure against the spring force of the return spring. In addition, a check valve is installed in the pilot passage to prevent flow from one port to the small hole, and the poppet acts as a large check valve that allows free flow from one port to the other port. Therefore, movable parts such as the slide table can be returned quickly without separately providing a large check valve, and the shut-off valve can be configured compactly.

Further, in the shut-off valve according to the present invention, a pilot passage is provided in the valve body,
Since it branches from the middle part of the main passage and communicates with one of the ports, there is no need for piping for refluxing the liquid flowing through the pilot passage, making it possible to save space and reduce costs.

〔Example〕

An embodiment of the present invention will be described below based on the drawings. FIG. 1 shows an example in which the mechanically operated shut-off valve V ₁ according to the present invention is combined with a flow rate control valve V ₂ and implemented in a feed control device for a machine tool. A hydraulic cylinder 93 that reciprocates the slide table 92 of the machine, a 4-port 3-position electromagnetic switching valve 94, and a shut-off valve that control the operation of the hydraulic cylinder 93.
Consists of V ₁ and flow control valve V ₂ . Solenoid switching valve 94
has solenoids a and b, and each port has a conduit 81 connected to the left chamber 93a of the hydraulic cylinder 93, and a conduit 81 connected to the first port 11 of the valve body 10 of both valves _V1 and _V2 . A conduit 82, a conduit 83 connected to a pressure source 95, and a conduit 84 connected to a tank 96 are connected, respectively.

The shut-off valve _V1 consists of a valve body 10, a cylindrical poppet 20 assembled to the valve body 10, a pilot valve 30, and a check valve 40, and is mechanically operated by a cam plate 91. The valve body 10 includes the first port 11 described above, the second port 12 to which the conduit 85 connected to the right chamber 93b of the hydraulic cylinder 93 is connected, and a substantially L-shaped main passage connecting both ports 11 and 12. 13, and a pilot passage 14 branching from an intermediate portion of the main passage 13 and continuing to the first port 11,
A poppet 20 is installed at the connecting portion of both passages 13 and 14, that is, a branching portion, and a pilot valve 30 and a check valve 4 are installed in the pilot passage 14.
0 is installed.

The poppet 20 is fitted into a large-diameter inner hole 14a of a pilot passage 14, which has a larger diameter than the main passage 13, so as to be movable in the vertical direction, and is biased upward by a return spring 22. A tapered valve portion 20a on which an annular valve seat 13a is seated, and a small hole 20b that allows constant communication between the second port 12 and the pilot passage 14.
have. Therefore, the poppet 20 closes the main passage 13 by the spring force of the return spring 22 when the liquid does not flow through the small hole 20b toward the pilot passage 14, and when the liquid does not flow through the small hole 20b toward the pilot passage 14. Small hole 2 when flowing
Due to the differential pressure generated by 0b, it moves downward against the spring force and opens the main passage 13. (The small hole described above functions similarly even if it is provided in the valve body 10.)
The poppet 20 also has an annular pressure receiving surface A that is exposed to the liquid supplied to the first port 11 even when the main passage 13 is closed and receives liquid pressure against the spring force. When pressure fluid is supplied to port 11, it moves downward under the action of check valve 40 to open main passage 13 and allow free flow of fluid from first port 11 to second port 12. Furthermore, the poppet 20 has a protrusion 20c and a notch 20 at its upper end.
d to reduce the shock when the valve portion 20a of the poppet 20 is seated on the valve seat 13a.

The pilot valve 30 is connected to the pilot passage 14.
Valve case 3 fitted into valve body 10 inside
1. It consists of a valve spool 32 that is fitted into the valve body 10 and the valve case 31 so as to be movable in the vertical direction and is urged upward by a return spring 33 via a retainer 34. The valve body 10 is attached to the upper end of the valve spool 32. The cam plate 91 protrudes outward.
A roller 35 that is pushed down by the roller 35 is rotatably assembled. This pilot valve 30 is
When the roller 35 and the cam plate 91 are engaged and the valve spool 32 is moved down, the pilot passage 1
4 is closed, and the pilot passage 14 is closed at other times.
is in the open state.

The flow rate control valve _V2 consists of a pressure compensating valve 50 and a variable throttle valve 60, which are interposed in a communicating passage 15 that connects both ports 11 and 12, independently of the main passage 13 and the pilot passage 14, and a shut-off valve V2. ₁ , when the fluid flow from the second port 12 to the first port 11 is blocked, the flow rate of the fluid flowing from the second port 12 to the first port 11 is controlled.

In this embodiment configured as described above, when the solenoid a of the electromagnetic switching valve 94 is excited from the state shown in the figure, pressure fluid from the pressure source 95 flows through the conduit 81 and flows into the left chamber 93a of the hydraulic cylinder 93. ,
Also, the liquid in the right chamber 93b of the hydraulic cylinder 93 passes through the conduit 85, the valve body 10, and the conduit 82 to the tank 96.
The slide table 92 is driven forward to the right. However, at the beginning of this forward drive, the roller 35 and the cam plate 91 are not engaged, and the pilot valve 30 keeps the pilot passage 14 open, so the hydraulic cylinder 9
A part of the liquid that returns to the tank 96 from the right chamber 93b of the valve body 10 flows from the main passage 13 to the pilot passage 14 through the small hole 20b of the poppet 20 in the valve body 10, and the remainder of the liquid mainly flows through the small hole of the poppet 20. The second port 1 is opened through the main passage 13, which is opened by the flow of liquid through 20b.
2 to the first port 11, and the slide table 92 is rapidly moved. Thus, the cam plate 91 engages the roller 35 and the valve spool 32
When the valve is moved downward, the pilot passage 14 closes, liquid no longer flows through the small hole 20b of the poppet 20, and the differential pressure across the small hole 20b disappears. When this happens, the poppet 20 is connected to the return spring 2.
2, the valve portion 20a seats on the valve seat 13a and closes the main passage 13. After the main passage 13 is closed in this way, the liquid that has flowed into the valve body ₁₀ is transferred from the second port 12 to the first
Since the fluid flows to the port 11 and the flow rate is controlled by the flow rate control valve _V2 , the slide table 92 is moved slowly and processed by the machine tool. This slow movement of the slide table 92 is stopped by demagnetizing the solenoid a.

Furthermore, when the solenoid b of the electromagnetic switching valve 94 is energized, pressure fluid from the pressure source 95 flows into the right chamber 93b of the hydraulic cylinder 93 via the conduit 82, the valve body 10, and the conduit 85, and also flows into the left chamber 93b of the hydraulic cylinder 93. Room 9
The fluid in 3a flows back to tank 96 through conduit 81, and slide table 92 is driven backward to the left. Therefore, during this backward drive, at least the check valve 40 (when the roller 35 and the cam plate 91 are engaged, the pilot valve 30 also) is connected from the first port 11 to the second port 12 through the pilot passage 14. In order to block the pressure fluid that is about to flow and prevent the pressure fluid from acting on the lower surface of the poppet 20, the poppet 20 is moved downward by the pressing force of the pressure fluid that acts on its pressure receiving surface A, and the first port is closed. 11 to the second port 12 allowing free flow of pressure fluid. Therefore, the slide table 92 is quickly returned. This quick return of the slide table 92 is stopped by demagnetizing the solenoid b, and the slide table 92 returns to the illustrated state.

By the way, in this embodiment, the shutoff valve _V1 is connected to the poppet 20 and the pilot valve 30.
By opening and closing the pilot valve 30, the poppet 20 can be moved to open and close the main passage 13, so even if the liquid flowing through the main passage 13 is at a high pressure and large flow rate,
By enlarging only the main passage 13 and poppet 20 while the valve spool 32 and check valve 40 of the pilot valve 30 remain small, the liquid can be optimally controlled. Therefore, according to this shut-off valve _V1 , in any case, the operation is performed by a small mechanical operating force that resists the weak spring force of the return spring 33 that urges the small valve spool 32 to its original position. The shut-off valve _V1 can be operated, the pushing up force (reaction force) acting on the slide table 92 can be reduced, and the machining accuracy of the machine tool can be improved. Also this shut off valve
According to V ₁ , since the main passage 13 is closed by the poppet 20 , the main passage 13 is effectively shut off, and the above-mentioned delay of the slide table 92 is controlled by the flow rate control valve V ₂ . Feed is precisely controlled.

In addition, in this embodiment, the shutoff valve V ₁
Even when the main passage 13 is closed, the poppet 20 has an annular pressure receiving surface that is exposed to the liquid supplied to the first port 11 and receives liquid pressure against the spring force of the return spring 22. A check valve 40 for blocking the flow to the small hole 20b is interposed in the passage 14, and the poppet 20 is connected to the first
Since it also functions as a check valve that allows free flow from the port 11 to the second port 12, the slide table 92 can be returned quickly without separately providing a large check valve _.
can be configured compactly. Furthermore, in this embodiment, the pilot passage 14 is provided in the valve body 10 and branches from the middle part of the main passage 13 and communicates with the first port 11, so that the liquid flowing through the pilot passage 14 can be refluxed. There is no need for piping for this purpose, and space and cost savings can be achieved.

In the above embodiment, the pilot valve 30 with the valve spool 32 as the valve body was used as the pilot valve, but the pilot valve 130 with the poppet 132 shown in FIG. 2 as the valve body was adopted as the pilot valve. It is also possible to do so. The pilot valve 130 includes a valve seat 131 fitted to the valve body 110 in the pilot passage 114, and a poppet fitted into the valve seat 131 so as to be movable in the vertical direction and urged upward by a return spring 133 via the retainer 134. 132, the poppet 13 is fitted into the valve body 110 so as to be movable in the vertical direction, and is connected to the poppet 13 via a spring holder 135 and a coil spring 136.
2, and a plunger 138 that is fitted into the cover 110A of the valve body 110 so as to be able to move downward from the position shown in the figure and comes into contact with the top surface of the rod 137. Roller 13
9 is rotatably assembled. In this pilot valve 130, a coil spring 136
Since the installation load is zero and the spring constant is larger than that of the return spring 133, the coil spring 136 functions as an operating force transmission member until the poppet 132 is seated on the valve seat 131, and thereafter. is rod 13
7. Functions as a buffer that allows the plunger 138 and roller 139 to move downward. Further, in this pilot valve 130, a through hole 132a is formed in the axis of the poppet 132, and a through hole 132a is formed in the axis of the poppet 132.
The seat diameter and seal diameter of the poppet 132 are substantially the same, so that the poppet 132 is not affected by hydraulic pressure. In the pilot valve 30, both seal diameters of the valve spool 32 are made substantially the same, so that the valve spool 32 is not affected by hydraulic pressure.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram in which a mechanically operated shut-off valve according to the present invention is used in combination with a flow rate control valve in a feed control device for a machine tool, and Fig. 2 is a partial sectional view showing another embodiment of the present invention. It is. Explanation of symbols, 10... Valve body, 11... First port (one port), 12... Second port (other port), 13... Main passage, 13a...
Valve seat, 14...Pilot passage, 20...Poppet, 20a...Valve portion, 20b...Small hole, 22...
Return spring, 30...Pilot valve, 32...Valve spool (valve body), 33...
Return spring, 40...Check valve, 91
...Cam plate, 92...Slide table,
93...hydraulic cylinder (hydraulic actuator),
A...Pressure receiving surface, V1...mechanically operated shut-off valve, V2...flow control valve.

Claims (1)

[Claims] 1. A mechanically operated shut-off valve that is connected in parallel to a flow rate control valve in the circuit of a hydraulic actuator used in a feed device for a movable part such as a slide table in a machine tool, and controls the feed speed of the movable part by the flow control valve. A valve body having two ports through which liquid flows in and out, a main passage connecting these two ports, and a pilot passage branching from the middle part of this main passage and continuing to one port, and the main passage in this valve body. The pilot passage and the other port have a tapered valve part that is movably inserted into a branching part between the passage and the pilot passage, seats on an annular valve seat provided in the main passage, and closes the main passage. When the liquid does not flow toward the pilot passage, the main passage is closed by a spring force, and when the liquid flows through the small hole towards the pilot passage, the main passage is closed against the spring force. A poppet that moves to open the main passage, and a valve body that is movably inserted into the pilot passage in the valve body, and when moved by a mechanical operation received from a movable part such as the slide table, the pilot A pilot valve is provided which closes the passage and returns to its original position by a spring force to open the pilot passage when the mechanical operation is released, and which also closes the main passage when the poppet closes the main passage. forming an annular pressure-receiving surface on the poppet that is exposed to the liquid supplied to the port and receives liquid pressure against the spring force acting on the poppet;
The mechanically operated shut-off valve further comprises a check valve provided in the pilot passage for blocking flow from the one port to the small hole via the pilot passage.