JP2005163860A - Directional selector valve with relief function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact directional selector valve with a relief function also reduced in cost. <P>SOLUTION: A relief valve 20 is formed in a spool 13 of the directional selector valve 10. A pressure chamber 21 communicating with a port B, a piston hole 22 communicating with one end of the pressure chamber, and a drain passage 19 communicating with the peripheral surface of the piston hole and a tank port T2 are formed in the axis of the spool 13 of the valve 10. A piston 24 forming the main valve of the relief valve 20 is stored in the hole 22, energized by a spring 27 to make it abut on a valve seat 23 at one end of the hole to cut out the port B from the port T3. The piston comprises a passage 31 having an orifice 30 allowing the pressure chamber to communicate with the spring chamber 26 at the other end, a first passage 32 communicating with the spring chamber, and a second passage 33 communicating with the drain passage 19. A spool hole 28 opening to the pressure chamber is formed at the axis of the piston, and a spool 34 forming the pilot valve is stored in the hole. The spool comprises a passage 38 allowing the passage 32 to communicate with the passage 23, energizes the spool in the pressure chamber direction by the spring 39, and cuts out the communication of the passage 32 with the passage 33. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a directional control valve with a relief function that is compact by incorporating the function of a relief valve into the directional control valve.

  In general hydraulic devices, relief valves are often installed on the inlet side and outlet side of the direction switching valve of the hydraulic circuit for setting the working pressure and for safety measures.

  FIG. 4A shows an overall view of a conventional direction switching valve having a relief valve attached to the inlet. The symbol is shown in FIG. The direction switching valve 50 is an electromagnetically operated 2/2 valve (2-port 2-position valve). The spool 53 is accommodated in the spool hole 52 of the valve body 51, and the spool 53 is attached by a centering spring 54 provided at one end thereof. The spool 53 is positioned at the center position where the round portion 53a blocks communication between the port B and the port B2 formed in the valve body 51, and the main spool 53 is spring-loaded by the solenoid 55 attached to the other end of the spool 53. It moves against 54 and connects port B and port B2. The G1 / 2 port of the external B port line is connected to the port B by a screw connection g1, and the G1 / 2 port of the external B2 port line is connected to the port B2 by a screw connection g2. Due to the communication between the ports B and B2, oil from the B port line flows through the port B to the port B2 and flows out to the B2 port line.

  The relief valve 56 is a cartridge type, and an attachment port 57 is formed in the valve body 51, the port 57 is communicated with a B port passage Lb that communicates the port B with the spool hole 52, and the relief valve 56 is attached to the port 57. A relief valve 56 is installed at the entrance of the direction switching valve 50. When an abnormal pressure is generated in the B port line connected to the direction switching valve 50 and the relief valve 56 performs a relief operation, oil from the B port line passes through the drain passage 58 of the relief valve 56 from the B port passage Lb. It flows out to the tank port T3 of the valve body 51. The G1 / 2 port of the external T3 tank port line is connected to the tank port T3 by a screw connection g3.

  Oil leaking into the pressure tube of the solenoid 55 is discharged to the tank port T through the tank port passage Lt of the valve body 51. An external T tank port line G1 / 4 port is connected to the tank port T by screw connection. The spring chamber 54a in which the spring 54 of the one-way switching valve 50 is arranged is connected to the tank port passage Lt by a passage 59 and a passage (not shown), and oil leaked into the spring chamber 54a is discharged to the tank port T.

  As described above, in the configuration of the valve device in which the relief valve is attached to the inlet or the outlet of the direction switching valve, each of the direction switching valve and the relief valve is provided even if the circuit such as the B port passage Lb is configured by piping or a manifold block. Was required and the space efficiency was poor. In addition, the man-hours for piping and manifold blocks have increased, and the cost has increased.

  Accordingly, an object of the present invention is to provide a direction switching valve with a relief function that is compact and can be reduced in cost by incorporating the function of a relief valve into the direction switching valve.

In order to solve the above-mentioned problems, a directional control valve with a relief function according to the present invention has a connection between ports formed around the spool hole of the valve body by moving a spool accommodated in the spool hole of the valve body. In the direction switching valve that releases the connection,
A pressure chamber communicating with a port connected to the line to be relief-controlled at the axial center of the spool at a position close to a port connected to a line to be relief-controlled among the ports of the valve body, and the pressure chamber and one end thereof Forming a piston hole that communicates, forming a drain passage that communicates with a tank line in the valve body, and communicating the drain passage with the peripheral surface of the piston hole,
The main piston is accommodated in the piston hole, a pilot spool hole that opens to the pressure chamber is formed in the axial center of the main piston, and the pilot spool is accommodated in the pilot spool hole,
The main piston communicates a port connected to a line where relief control is desired and a main spring chamber formed at the other end of the piston hole, a pilot passage having an orifice in the middle, and a downstream side of the orifice of the pilot passage Or a first passage communicating with the spring chamber and a second passage communicating with the drain passage, and the piston is biased by a main spring disposed in the spring chamber, whereby the piston Abuts on the valve seat formed on the inner wall surface of the valve body surrounding one end of the hole, shuts off the port connected to the line to be relief-controlled and the drain passage;
The pilot spool includes a communication passage communicating the first passage and the second passage, and the pilot spool is disposed in a pilot spring chamber formed at the other end of the pilot spool hole. And the first passage and the second passage are shut off by being biased toward the pressure chamber by
When the pressure of the port connected to the line where the relief control is desired reaches a predetermined value or more, the pilot spool moves against the urging force of the pilot spring due to the pressure, and the communication passage is connected to the first passage and the second passage. The main piston chamber is connected to the main spring chamber by a pressure difference between the main spring chamber and a port connected to a line to be subjected to relief control. It is made to move against an urging force, whereby the pressure chamber and the drain passage are communicated with each other, and the fluid of the port connected to the line to be subjected to the relief control is released to the drain passage.

  In the above directional control valve with a relief function, the fluid from the port of the valve main body connected to the line for which relief control is desired acts on one end of the main piston and the pilot spool in the main spool, and at the same time through the pilot passage, 1 enters the main spring chamber from the pilot passage and acts on the other end of the main piston. When the fluid pressure of the port rises and exceeds the urging force of the pilot spring, the pilot spool moves against the pilot spring, and the pilot spool communication passage communicates with the pilot passage of the main piston, thereby Fluid from the port enters the drain passage through the pilot passage, the first passage, the communication passage, and the second passage, or through the pilot passage, the main spring chamber, the first passage, the communication passage, and the second passage. The pressure in the main spring chamber drops due to the flow and pressure loss due to the pilot passage orifice, creating a differential pressure between the port and the main spring chamber, and the main piston moves against the urging force of the main spring to open the valve. Then, the port and the drain passage communicate with each other, and fluid escapes from the port to the drain passage. Pressure which is connected to the bets line is regulated so as not to over adjust the pressure set by the pilot spring.

  According to the directional control valve with a relief function of the present invention, the balance piston type relief valve basically has a compact component configuration by consolidating the functions of the pilot valve in the main piston, and the size of the relief valve is larger than that of the conventional product. Was significantly reduced, and a relief valve could be constructed and incorporated in the spool of the direction switching valve. Thereby, it is not necessary to separately attach a relief valve to the direction switching valve, the processing of the valve mounting port is unnecessary, the space is small, and the cost can be reduced.

  Examples of the present invention will be described in detail below. FIG. 1 is a block diagram showing an embodiment of a directional control valve with a relief function of the present invention. The directional switching valve 10 </ b> A with a relief function of the present embodiment is configured with a balance piston type relief valve 20 in a part of the main spool 13 of the directional switching valve 10. In this embodiment, the direction switching valve 10 is an electromagnetically operated 2/2 valve (2-port 2-position valve), and includes a solenoid 15 in the valve body 11. A main spool hole 12 is formed in the valve body 11, and a port B and a port B2 are communicated with the peripheral surface of the main spool hole 12.

  A main spool 13 having a round portion 13a in the center is accommodated in the main spool hole 12, a centering spring 14 is provided on one end side of the main spool 13, and the solenoid 15 is provided on the other end side of the main spool 13. ing. The centering spring 14 biases the main spool 13 toward the other end, thereby positioning the main spool 13 at a central position where the round portion 13a blocks communication between the port B and the port B2. . The solenoid 15 pushes the main spool 13 with the push pin 15a by exciting the electromagnet to move the main spool 13 against the spring 15, and the round portion 13a that blocks communication between the port B and the port B2 is connected to the port. It opens in the direction of B2, and the port B and the port B2 are communicated. Thereby, the oil from the B port line connected to the port B flows through the port B to the port B2, and flows out to the B2 port line connected to the port B2.

  A tank port T3 is connected to the peripheral surface following the port B of the main spool hole 12, and the oil that has entered the pressure tube 15b of the solenoid 15 is discharged to the tank port T3. The spring chamber 14a in which the spring 14 at one end of the main spool hole 12 is arranged is connected to the tank port T3 by a passage 17, and the oil that has entered the spring chamber 14a is discharged to the tank port T3.

  In this embodiment, in order to perform relief control of the B port line connected to the port B of the direction switching valve 10, the balance piston type relief valve 20 is configured in the other end portion near the port B of the main spool 13. FIG. 2 shows an enlarged view of the relief valve.

  As shown in FIG. 2, a pressure chamber 21 communicating with the port B by a passage 21 a and a piston hole 22 having one end communicating with the pressure chamber 21 are formed in the shaft center of the main spool 13. A drain passage 19 that communicates with the peripheral surface of the piston hole 22 through the passage 19a at a position near one end and communicates with the tank port T3 of the valve body 11 is formed in the wall portion surrounding the hole 22. A main piston 24 is accommodated in the piston hole 22, and a tapered valve seat 23 on which one end of the main piston 24 is seated is formed on the inner wall surface of the main spool 13 surrounding one end of the piston hole 22. A main spring 27 is arranged in a main spring chamber 26 formed at the end to constitute the main valve of the balance piston type relief valve 20.

  The main spring 27 urges the main piston 24 toward the pressure chamber 21 to bring one end of the main piston 24 into contact with the valve seat 23, thereby shutting off the pressure chamber 21 and the drain passage 19. For example, the port B connected to the pressure chamber 21 via the passage 21a and the tank port T3 connected to the drain passage 19 are blocked. The main spring chamber 26 is formed by attaching a plug 25 to the other end of the piston hole 22 from the outer surface of the main spool 13 via a sealing material, and the main spring 27 is attached to the inside of the plug 25, thereby 26.

  A pilot spool hole 28 that opens to the pressure chamber 21 is formed in the axial center of the main piston 24. Further, the main piston 24 is provided on a longitudinal pilot passage 31 having one end communicating with the pressure chamber 21 through the orifice 30 and the other end communicating with the main spring chamber 26, and an inner peripheral surface of the piston 24. A first passage 32 in the circumferential direction communicating with the pilot passage 31 on the downstream side of 30 and one end communicated with the peripheral surface of the pilot spool hole 28 at a position closer to the pressure chamber 21 than the first passage, and the other end A second passage 33 communicating with the drain passage 19 is formed.

  The pilot spool 34 is accommodated in the pilot spool hole 28, and a communication passage 38 that communicates the first passage 32 and the second passage 33 of the main piston 24 is formed on the peripheral surface of the pilot spool 34. A pilot spring 39 is arranged in a pilot spring chamber 37 formed at the other end of the hole 28, and a pilot valve of the balance piston type relief valve 20 is configured in the main piston 24. The pilot spring 39 urges the pilot spool 34 toward the pressure chamber 21, thereby moving the position of the communication passage 38 toward the pressure chamber 21, and the first passage 32 and the second passage of the main piston 24. 33 communication is cut off.

  The pilot spool 34 is improved in sliding stability by a sliding O-ring 40 attached to a peripheral surface near one end to prevent oil front leakage, and a ring stopper 41 attached to the main piston 24 at one end of the pilot spool hole 28. To prevent the pilot spool hole 28 from coming off. The passage 35 opened to the pilot spring chamber 37 is a passage for discharging the oil accumulated in the pilot spring chamber 37 and does not communicate with the first passage 32. The passage 35a penetrates the main piston 24 and passes through the passage 19a. Then, it communicates with the drain passage 19.

  The operation of the relief function in the directional switching valve with relief function 10A will be described. In the block position where the main spool 13 blocks the port B and the port B2, the pressure oil acting on the port B is the pressure chamber of the main spool 13. 21 and acts on one end of the main piston 24 and the pilot spool 34 of the relief valve 20, and at the same time enters the first passage 32 from the pilot passage 31 and enters the main spring chamber 26 from the pilot passage 31. Acts on the other end. When the pressure of the port B is not more than the relief set pressure (adjusted pressure) controlled by the pilot spring 39, that is, not more than the urging force of the pilot spring 39, the pilot spool 34 is in the position shown in FIG. Since the first passage 32 and the second passage 33 are blocked, the main piston 24 is in a position in contact with the valve seat 23 in the figure, and the relief valve 20 is closed.

  When the pressure of the port B rises due to an abnormality such as a hydraulic pump provided in the B port line connected to the port B and exceeds the urging force of the pilot spring 39, the pilot spool 34 resists the pilot spring 39. The communication passage 38 of the pilot spool 34 communicates with the first and second passages 32 and 33 of the main piston 24, and the pressure chamber 21 and the drain passage 19 communicate with each other. As a result, oil flows from the pressure chamber 21 to the drain passage 19 via the pilot passage 31, the first passage 32, the communication passage 38 and the second passage 33, and the main spring chamber is caused by pressure loss due to the orifice 30 of the pilot passage 31. The pressure of 26 is reduced, and a differential pressure is generated between the pressure chamber 21 and the main spring chamber 26. As a result, the main piston 24 moves against the urging force of the main spring 27, opens away from the valve seat 23, the pressure chamber 21 and the drain passage 19 communicate with each other, and the port B and the tank port T3 are connected. Communicating, pressure oil escapes from port B to tank port T3.

  Due to the oil flow from the port B to the tank port T3, the pressure in the pressure chamber 21 drops instantaneously, and the pilot spool 34 moves toward the pressure chamber 21 by the urging force of the pilot spring 39. The communication between the first and second passages 32 and 33 of the main piston 24 by the communication passage 38 is blocked. Along with this, the pressure drop in the main spring chamber 26 disappears, the main piston 24 moves toward the pressure chamber 21 by the urging force of the pilot spring 39, contacts the valve seat 23 and closes. As a result, no oil flows out from the port B to the tank port T3, and when the pressure at the port B recovers and rises, the communication passage 38 of the pilot spool 34 is connected to the first and second main pistons 24 as described above. 2, the main piston 24 is opened, and the pressure oil in the port B is released to the tank port T3. Such opening and closing of communication between the first and second passages 32 and 33 of the main piston 24 by the communication passage 38 of the pilot spool 34 is repeated until the pressure of the B port line is reduced to the relief pressure set by the pilot spring 39. The B port line pressure is controlled so as not to exceed the regulated pressure.

  When the main spool 13 communicates the port B and the port B2, if an abnormal pressure rise occurs due to, for example, a surge in the B2 port line connected to the port B2, the abnormal pressure is changed from the port B2 to the port B. Therefore, the pressure in the pressure chamber 21 is increased, so that the relief control of the B2 port line can be performed by the similar relief operation by the relief valve 20. That is, when the port B and the port B2 communicate with each other, relief control is performed not only for the B port line but also for the B2 port line.

  However, in order to ensure the relief of the B2 port line, it is preferable to configure a relief valve dedicated to the B2 port line in the main spool 13 of the direction switching valve 10. That is, at a position close to the port B2, a pressure chamber communicating with the port B2 and a piston hole with one end communicating with the pressure chamber are provided in the axial center of the main piston 13, and the main piston is accommodated in the piston hole. In the same manner as described above, a main valve and a pilot valve may be incorporated in the main piston to provide a relief valve.

  As described above, in the present invention, the balance piston type relief valve basically has the function of the pilot valve integrated in the main piston to form a compact component structure. Therefore, the size of the relief valve is about 50 times that of the conventional product. %, The relief valve can be constructed and incorporated in the spool of the direction switching valve. Thereby, it is not necessary to separately attach a relief valve to the direction switching valve, the processing of the valve mounting port is unnecessary, the space is small, and the cost can be reduced.

  An overall view of the direction switching valve 10A with a relief function of the present embodiment is shown in FIG. As shown in FIG. 3A, the G1 / 2 port of the external B port line is connected to the port B by the screw coupling f1, and the G1 / 2 port of the external B2 port line is connected to the port B2. They are connected by a coupling f2. The G1 / 4 port of the external T3 tank port line is connected to the tank port T3 by screw connection. The symbol of the direction switching valve 10A with the relief function is as shown in FIG.

  In the above embodiment, the present invention is applied to an electromagnetically operated two-port / 2-position directional switching valve. However, the present invention is applicable to various types of multiple-port / multi-position such as a 4-port / 3-position valve. It can be applied to a direction switching valve. The operation method of the direction switching valve can also be applied to various types such as manual operation and pilot operation.

It is a block diagram which shows one Example of the direction switching valve with a relief function of this invention. It is a block diagram which shows the part of the balance piston type relief valve comprised by the main spool of the direction switching valve with a relief function of FIG. It is the whole figure (a) which shows the direction switching valve with a relief function of FIG. 1, and the figure (b) which shows the symbol. It is the whole figure (a) which shows the conventional direction switching valve which attached the relief valve separately, and the figure (b) which shows the symbol.

Explanation of symbols

10A: Directional switching valve with relief function, 10: Directional switching valve,
11: Valve body, 13: Main spool, 19: Drain passage,
20: Balance piston type relief valve, 21: Pressure chamber, 22: Piston hole,
23: Valve seat, 24: Main piston, 26: Main spring chamber,
27: main spring, 28: spool hole, 30: orifice,
31: Pilot passage, 32: First passage, 33: Second passage,
34: Pilot spool, 38: Communication passage, 39: Pilot spring,
B, B2: Port, T3: Tank port

Claims (1)

In the direction switching valve that performs connection and disconnection between ports formed around the spool hole of the valve body by moving the spool accommodated in the spool hole of the valve body,
A pressure chamber communicating with a port connected to the line to be relief-controlled at the axial center of the spool at a position close to a port connected to a line to be relief-controlled among the ports of the valve body, and the pressure chamber and one end thereof Forming a piston hole that communicates, forming a drain passage that communicates with a tank line in the valve body, and communicating the drain passage with the peripheral surface of the piston hole,
The main piston is accommodated in the piston hole, a pilot spool hole that opens to the pressure chamber is formed in the axial center of the main piston, and the pilot spool is accommodated in the pilot spool hole,
The main piston communicates a port connected to a line where relief control is desired and a main spring chamber formed at the other end of the piston hole, a pilot passage having an orifice in the middle, and a downstream side of the orifice of the pilot passage Or a first passage communicating with the spring chamber and a second passage communicating with the drain passage, and the piston is biased by a main spring disposed in the spring chamber, whereby the piston Abuts on the valve seat formed on the inner wall surface of the valve body surrounding one end of the hole, shuts off the port connected to the line to be relief-controlled and the drain passage;
The pilot spool includes a communication passage communicating the first passage and the second passage, and the pilot spool is disposed in a pilot spring chamber formed at the other end of the pilot spool hole. And the first passage and the second passage are shut off by being biased toward the pressure chamber by
When the pressure of the port connected to the line where the relief control is desired reaches a predetermined value or more, the pilot spool moves against the urging force of the pilot spring due to the pressure, and the communication passage is connected to the first passage and the second passage. The main piston chamber is connected to the main spring chamber by a differential pressure between the main spring chamber and a port connected to a line to be subjected to relief control. A direction with a relief function that moves against an urging force, thereby causing the pressure chamber and the drain passage to communicate with each other, and allows fluid in a port connected to a line to be subjected to relief control to escape to the drain passage. Switching valve.

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