JP3373905B2 - Pilot operated switching valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot operated switching valve for a hydraulic actuator which operates by receiving a pressurized liquid from a pressure intensifier. 2. Description of the Related Art A pilot operation switching valve of this type is disclosed in Japanese Patent Publication No. Hei 5-12589. According to this, between an input chamber connected to a pressurized pump, which is a kind of air-operated pressure intensifier, and a return chamber to be drained, a single-acting type that communicates with both chambers via valve seats respectively. An output chamber connected to the hydraulic cylinder is formed. In the output chamber, two poppets biased by a common spring to be seated on each valve seat are installed back to back, and the poppet is opened and closed by a piston operated by the operation of a pilot solenoid valve. I have. [0003] However, in this configuration, when the hydraulic fluid is supplied to the hydraulic cylinder, the poppet sits on the valve seat between the output chamber and the return chamber, so that the high pressure from the pressure intensifier increases. Although it is advantageous in that the internal leakage of the pressure fluid can be reduced, since it is for a single-acting hydraulic cylinder having one working chamber, it is applied to a movable hydraulic actuator having two working chambers. In this case, there is a problem that a configuration for operating the hydraulic actuator is complicated because a switching valve is separately required. The present invention solves such a problem, and when supplying hydraulic fluid from a pressure intensifier to a hydraulic actuator, while maintaining the advantage of reducing internal leakage of the hydraulic fluid, a double-acting valve is provided by one valve. The present invention realizes a pilot-operated switching valve adapted to be applied to a hydraulic actuator. [0004] Therefore, in the present invention,
A double-acting type fluid in which the pressurized fluid from the pressure intensifier is supplied to one working chamber when operating in one direction, and is supplied to the other working chamber when returning in the other direction. A pilot operated switching valve for a pressure actuator, wherein a first output chamber connected to one working chamber of a hydraulic actuator is connected between a first input chamber connected to a pressure intensifier and a return chamber drained. The poppet is formed so as to communicate with both chambers via a first valve seat and a second valve seat, respectively, and seats on the first valve seat between the first input chamber and the first output chamber from the first input chamber side. Is installed, and a spring for biasing the poppet in the seating direction is provided.
A sliding hole connected to the return chamber, wherein the sliding hole has a second input chamber through which pressure fluid for return operation is led and a second output connected to the other working chamber of the hydraulic actuator; The second output chamber is formed in the sliding hole at a normal position obtained by the bias of a spring.
A spool that communicates with the input chamber and communicates with the return chamber and moves in the axial direction to an operating position against the urging of the spring so that the second output chamber communicates with the second input chamber and is isolated from the return chamber is slidable. And the spool contacts the poppet from the first output chamber side with the poppet portion seated on the second valve seat by moving to the operating position against the bias of the spring, and separates the poppet from the first valve seat. And a piston that moves by the pressure of a pilot chamber controlled to be supplied and discharged by a pilot solenoid valve in order to move the spool to an operating position against the bias of a spring. In such a pilot operation switching valve according to the present invention, when the spool is moved against the spring, the poppet is separated from the first valve seat by the protrusion of the spool, and the poppet of the spool is moved. The part is seated on the second valve seat, and the spool communicates between the second input chamber and the second output chamber, so that the pressurized liquid from the pressure intensifier is passed through the first input chamber and the first output chamber to one side. Guide the working chamber to actuate the hydraulic actuator in one direction or the second input chamber and the second output chamber to guide the hydraulic fluid to the other working chamber and return the hydraulic actuator to the other direction. Can be. When the hydraulic cylinder is operated in one direction by the hydraulic fluid from the pressure intensifier, the poppet portion of the spool is seated on the second valve seat. it can. As described above, since one valve can be used to operate the double-acting hydraulic actuator, the structure for operating the double-acting hydraulic actuator can be simplified. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a pilot operated switching valve is indicated by V, and 1 is a main body thereof provided with end covers 2 and 3. Body 1
Is provided with a valve hole 4 closed by end covers 2 and 3. Reference numeral 5 denotes a sleeve inserted and installed on the end cover 3 side of the valve hole 4. A first output chamber 6 is provided in the sleeve 5 and a first input chamber 8 communicating with the first output chamber 6 through the first valve seat 7. Is provided on the end cover 3 side of the first output chamber 6. Further, a return chamber 10 communicating with the first output chamber through a second valve seat 9 provided in the sleeve 5 is formed in the inner part of the valve hole 4 inside the sleeve 5. The remaining portion of the valve hole 4 is formed with a sliding hole 13 and a piston hole 14 which are slidably fitted so that the spool 11 and a piston 12 integrally formed with the spool 11 can be moved in the axial direction. are doing. The sliding hole 13 has a second
The output chamber 15 and the second input chamber 16 are axially spaced from each other with the second output chamber 15 facing the return chamber 10.
The second output chamber 15 according to the axial movement of the spool 11.
Control land 1 for selectively communicating with the return chamber and the second input chamber 16
7 are provided. A pilot chamber 18 is provided in the piston hole 14.
And the spring chamber 19 are formed on both sides of the piston 12 with the pilot chamber 18 on the end cover 2 side. The spring 20 installed in the spring chamber 19 causes the control land 17 to control the second output chamber 15 by the control land 17. It is urged to the normal position shown in FIG. A protrusion 21 extending into the first output chamber 6 is provided at an end of the spool 11 on the return chamber 10 side.
And the poppet portion 22 is formed, and the poppet portion 22 is seated on the second valve seat 9 by the axial movement of the spool 11 against the bias of the spring 20, and the projection 21 is moved to the first input chamber 8. A spherical poppet 23 that is seated on the first valve seat 8 from the side is brought into contact with the poppet 23 and is separated from the first valve seat 7. Reference numeral 24 denotes the poppet 23 in the first input chamber 8.
In the guide tube 24, a spring 25 for urging the poppet 23 to be seated on the first valve seat 7 is provided. Reference numeral 26 denotes a pilot solenoid valve which, when in a normal position, connects a pilot passage 27 provided in the main body 1 to the spring chamber 1.
9, the pilot chamber 18 communicates with the return chamber 10, and in the operating position, the spring chamber 19 communicates with the return chamber 10 and the pilot chamber 18 communicates with the pilot passage 27. Installed above. Reference numeral 28 denotes a spacer interposed between the sleeve 5 and the end cover 3, and reference numeral 29 denotes a first input hole communicating with the first input chamber 8;
0 is the first output hole leading to the first output chamber, 31 is the return chamber 10
A reference numeral 32 denotes a second output hole leading to the second output chamber 15, and a reference numeral 32 denotes a second input hole leading to the second input chamber 16. Such a pilot operation switching valve V is installed as shown in FIG. In FIG. 2, the valve V is shown with a suffix 1, 2 as a valve V1 for the output cylinder 50 and a valve V2 for the output cylinder 51. That is, reference numeral 34 in FIG. 2 denotes a pressure intensifier in which the pressure increasing effect is obtained by the rod 37 of the drive cylinder 36 which enters the pressure increasing chamber 35. The operation chambers 38, 39 on the head side and the rod side of the drive cylinder 36 are connected to a switching valve 40 by supply / discharge paths 41, 42, and a sequence valve 43 with a check valve is installed in the supply / discharge path 41. Have been. In addition, booster chamber 3
5, the sequence valve 43 and the switching valve 40 in the supply / discharge path 41
Are connected by a branch path 47 and the switching valve 40
, The control flow of the check valve 44 is obtained by the pilot pressure from the supply / discharge path 42. Reference numerals 50 and 51 denote double-acting output cylinders which perform processing such as punching.
The working chambers 52 on the head side of 0 and 51 are respectively connected to the first output holes 30 of the valves V1 and V2 via supply / discharge pipe lines 53, and the working chamber 54 on the rod side is a supply / discharge pipe. It is connected to the second output hole 32 via the path 55. And each valve V
1, the first input hole 29 of V2 is connected to the booster 3
4 and the valves V1, V2
The second input hole 33 is connected to the supply / discharge path 42 by a pipe 57, and the return hole 31 is connected to the tank T of the switching valve 40 by a pipe 58.
The pilot passage 27 of each of the valves V1 and V2 is connected to the hydraulic pressure source P of the switching valve 40 by a pipe 59.
It is connected to the supply path leading to. Next, the operation of this embodiment will be described. In FIG. 2, both output cylinders 50 and 51 are at rest with the pistons at the retreat end, and the valves V1 and V2 are in the normal position as shown in FIG. 1 with the pilot solenoid valve 26 in the normal position. . At this time, the first output chamber 6 is cut off from the first input chamber 8 by the poppet 23 seated on the first valve seat 7, and the second output chamber 15 is also cut off from the second input chamber 16 by the control land 17. Thus, both output chambers 6 and 15 are in communication with the return chamber 10. When machining is performed using one of the two output cylinders 50 and 51, for example, 50, the pilot solenoid valve 26 is switched to the operating position and the switching valve 40 is switched to the left position in the valve V1 connected to the output cylinder 50. As a result, in the valve V1, the spool 11 is moved to the operating position by the pressurized liquid introduced into the pilot chamber 18 via the piston 12 against the bias of the spring 20, and the second output chamber 15 is controlled. The poppet portion 22 is seated on the second valve seat 9, and the poppet 23 is separated from the first valve seat 7 by the projection 21 while being isolated from the return chamber 10 by the land 17 and communicating with the second input chamber 15. The first output chamber 6 is blocked from the return chamber 10 and communicates with the first input chamber 8. Then, the pressure liquid guided to the supply / discharge passage 41 by the switching valve 40 is introduced into the pressure-intensifying chamber 35 through the branch passage 47, and from there through the conduit 56, the first input chamber 8, and the first output chamber 6. The output cylinder 50 is introduced into the working chamber 52 of the output cylinder 50,
The piston moves forward until a processing tool portion (not shown) operated by the piston comes into contact with a work (not shown). When the pressure of the hydraulic fluid supplied from the hydraulic pressure source P rises due to the contact with the workpiece, the sequence valve 43 is opened, whereby the hydraulic fluid is introduced into the working chamber 38 of the drive cylinder 36 and the rod 37 Starts moving forward, whereby the pressure increasing action by the rod 37 in the pressure increasing chamber 35 is started. For this reason, the working chamber 52 of the output cylinder 50 is
An extremely high pressure fluid is guided to the, and the piston of the output cylinder 50 continues to advance to process the workpiece. The liquid in the working chamber 54 is supplied to the second output chamber 15 and the second input chamber 1 of the valve V1 with the advance of the piston.
6. Drained into the tank T through the conduit 58. When the machining is completed, the switching valve 40 is switched to the right position, whereby the pressure fluid guided to the supply / discharge passage 42 is
While being introduced into the working chamber of the driving cylinder 36, the working chamber 5 of the output cylinder 50 passes through the pipe 57 from the second input chamber 16 in the communicating state in the valve V <b> 1 to the second output chamber 15.
4 is introduced. And the pilot operated check valve 44
Is controlled by the pilot pressure from the supply / discharge passage 42, the drive cylinder 36 is operated to return, and the piston of the output cylinder 50 is also returned to the retracted end. When the return operation of each of the cylinders 36 and 50 is completed, the switching valve 40 is switched to the neutral position as shown in FIG. 2, the valve V1 is switched to the pilot solenoid valve 26 to the normal position, and the spool 11 is switched to the normal position. Returned by the spring 20, the poppet 23 is also seated on the first valve seat 7 and switched to the normal position again. When the output cylinder 51 is operated, the valve V2 in the above operation is switched to operate in the same manner as the output cylinder 50. In the present embodiment, when the high pressure fluid subjected to the pressure increasing action from the pressure increasing chamber 35 is supplied to the action chamber 52 of the output cylinder 50 or 51, the poppet portion 22 of the spool 11 is connected to the second valve. Since the user sits on the seat 9, internal leakage from the first output chamber 6 to the return chamber 10 can be extremely reduced. Further, since the first and second output chambers 6 and 15 are communicated with the return chamber 10 at the normal position, even if one of the valves V1 and V2 is switched to the operating position, the valve V maintained at the normal position.
In the case of 1 or V2, the pipelines 53 and 55 are not pressurized, and the durability of the pipelines 53 and 55 is increased. This is particularly advantageous when these pipelines 53 and 55 are formed of rubber hoses. Then, since the poppet 23 is seated on the first valve seat 7 from the first input chamber 8 side in the normal position, the valves V1,
Even if one of the valves V2 is switched to the operating position and the high pressure due to the pressure increase acts on the line 56, the valves V1, V which are in the normal position
On the other hand, the poppet 23 is further pressed by the valve seat 7 by the high pressure guided to the first input chamber 8, and the poppet 23 is tightly sealed, and leakage to the first output chamber 6 is suppressed well. In addition,
The output cylinders 50 and 51 can be replaced with a double-acting swing motor. As described above, according to the present invention, the double-acting hydraulic actuator can be operated with a single valve by receiving the pressurized liquid from the pressure intensifier so that the internal leakage is reduced. The structure for operating the pressure actuator is simplified. Further, since both the first and second output chambers are communicated with the return chamber at the normal position, even if a high pressure is introduced into the first and second input chambers, a pipe between each output chamber and the working chamber of the hydraulic actuator is provided. The hydraulic actuator can be stopped in a state where the passage is not pressurized, and the durability of this passage can be increased. Further, since the poppet is seated on the first valve seat from the side of the first input chamber, even if high-pressure hydraulic fluid from the pressure intensifier is introduced into the first input chamber at the normal position, the poppet is moved by the hydraulic fluid. The seat is firmly seated on the one valve seat, and leakage to the first output chamber side can be satisfactorily suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing one embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram showing a use state of one embodiment of the present invention. FIG. 3 is a diagram showing an embodiment of the present invention by circuit symbols. [Description of Signs] 6 First output chamber 7 First valve seat 8 First input chamber 9 Second valve seat 10 Return chamber 11 Spool 12 Piston 13 Sliding hole 15 Second output chamber 16 Second input chamber 18 Pilot chamber 20 , 25 spring 21 protrusion 22 poppet part 23 poppet 26 pilot solenoid valve 34 pressure intensifier 50, 51 hydraulic actuator (output cylinder) 52, 54 working chamber

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16K 31/36-31/42 F16K 11/07

Claims (1)

(57) [Claim 1] The pressure fluid from the pressure intensifier is supplied to one working chamber when operating in one direction, and the other is used when returning in the other direction. A pilot-operated switching valve for a double-acting hydraulic actuator in which hydraulic fluid is supplied to an action chamber,
A first output chamber connected to one of the working chambers of the hydraulic actuator is connected between the first input chamber connected to the pressure intensifier and a return chamber to be drained by the first valve seat and the second valve chamber. A poppet is formed so as to communicate through a valve seat, and a poppet seated from the first input chamber side is installed on a first valve seat between the first input chamber and the first output chamber, and the poppet is urged in a seating direction. And a sliding hole connected to the return chamber. The sliding hole has a second input chamber into which pressure fluid for return operation is guided and the other working chamber of the hydraulic actuator. And a second output chamber connected to the second input chamber is formed in the sliding hole at a normal position obtained by the bias of a spring. The second output chamber is connected to the second input chamber by an axial movement to an operating position that is in communication with the return chamber and that is opposed to the bias of the spring. And a poppet portion seated on the second valve seat by moving to a working position against the bias of the spring, and a poppet from the first output chamber side. And a protrusion that abuts against the first valve seat to separate the spool from the first valve seat, and moves the spool to the operating position against the bias of the spring. A pilot-operated switching valve characterized by having a piston that is moved by a piston.