Pilot Check Valve

Abstract

To provide a pilot check valve capable of holding residual pressure in a fluid compressor when a residual pressure exhausting portion is failed.SOLUTION: A pilot check valve 10 has a first body 18 that has input and output ports 11 and 12, a main channel 13 that communicates with these ports, and a check valve body 14 that is provided in the main channel and permits a flow of a pressure fluid from the input port toward the output port. The valve body prevents a flow from the output port toward the input port side by the supplying and draining of a pilot fluid or permits the same flow. The check valve has a residual pressure exhaust channel 15 that is connected to a center hole 37 of the main channel at one end and is connected to an exhaust hole 56 of the body at the other end, a seal member 48 provided in the exhaust channel, and a push rod 45 that moves the check valve body to a position where the flow from the output port side toward the input port side of the main channel is permitted, and simultaneously moves a seal portion to a position where a flow from a connecting portion toward the exhaust hole is permitted.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pilot check valve having a residual pressure exhaust function for exhausting residual pressure in fluid pressure equipment such as a fluid pressure cylinder. [Background technology]

[0002] Conventionally, a pilot check valve has been known which includes an input port for connection to a pressure fluid source, an output port for connection to a fluid pressure device such as a fluid pressure cylinder, a main flow path connecting the input port and the output port, and a check valve element which is provided on the main flow path and allows a fluid to flow from the input port toward the output port, and which can be selectively moved by supplying or discharging pilot air between a first position which blocks the flow from the output port toward the input port, and a second position which allows the same flow, as shown in Patent Document 1, for example.

[0003] The pilot check valve described in Patent Document 1 is provided with a residual pressure exhaust part that, when the fluid pressure device stops for some reason, can exhaust the pressurized fluid (residual pressure) trapped inside the fluid pressure device to the outside through a residual pressure exhaust passage and a vent hole, as necessary. This residual pressure exhaust part has a valve body that is opened and closed by the supply and discharge of pilot air, and when the pilot air pressure is acting, the valve body blocks the flow of pressurized fluid from the output port toward the vent hole through the residual pressure exhaust passage.

[0004] However, in such a conventional pilot check valve with residual pressure exhaust valve, the residual pressure exhaust flow path is connected to the main flow path downstream of the check valve body on the output port side. Therefore, if there is a problem with the sealing ability of the valve body in the residual pressure exhaust section, in an emergency such as a power outage, there is a risk that the pressurized fluid that should be contained in the fluid pressure device will be exhausted to the outside from the exhaust hole through the residual pressure exhaust flow path, and in that case, the check function of the check valve body provided in the main flow path will be lost. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-9662 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, a technical object of the present invention is to provide a pilot check valve that, in the unlikely event that a problem occurs in the sealing ability of the valve body in the residual pressure release section, can retain the pressurized fluid sealed downstream of the check valve body by the check function of the check valve body in that position in an emergency such as a power outage. [Means for solving the problem]

[0007] In order to solve the problems, the present invention provides a pilot check valve comprising: a first body having an input port and an output port; a main flow path provided in the first body and connecting the input port and the output port; and a check valve element provided on the main flow path and allowing a flow of pressure fluid from a primary side connected to the input port toward a secondary side connected to the output port, wherein the check valve element is configured so that, by supplying or discharging pilot fluid, the check valve element can be selectively moved to a position where it blocks the flow from the output port toward the input port and a position where it allows the flow. the pressure release valve has one end connected to a connection part formed on the primary side of the main flow path and the other end connected to an exhaust hole opened in the first body; a seal part provided on the residual pressure exhaust flow path and configured to block the flow of pressurized fluid from the connection part of the main flow path toward the exhaust hole; and an operating part that is capable of moving the check valve body to a position that allows the flow of pressurized fluid from the secondary side toward the primary side in the main flow path, and simultaneously moving the seal part to a position that allows the flow of pressurized fluid from the connection part of the main flow path toward the exhaust hole in the residual pressure exhaust flow path.

[0008] In this case, preferably, the first body is formed in a cylindrical shape extending in the axial direction and has a base end and a tip end at both axial ends, a through hole extending along the axial direction is formed within the first body, the input port is connected to a first opening that opens into the middle part of the first body in the axial direction, and the output port is connected to a second opening that opens into the base end part of the first body in the axial direction, the check valve element is supported at the axial base end part of the through hole extending in the axial direction so as to be axially movable, and the operating part is housed in the through hole on the axial tip side of the check valve element so as to be axially movable.

[0009] Also, preferably, the operating portion is a rod member extending along the through hole, the outer diameter of the rod member is smaller than the inner diameter of the through hole, and the gap formed between the outer peripheral surface of the rod member and the inner peripheral surface of the through hole forms the residual pressure exhaust flow path.

[0010] Preferably, the sealing portion has a groove formed in an annular shape on the outer peripheral surface of the rod member and a sealing member housed in the groove, the sealing member being a lip-type sealing member, and the lip portion of the sealing member is formed so as to incline radially outward as it progresses toward the base end in the axial direction.

[0011] Preferably, a portion of the through hole communicating the first opening and the second opening forms a portion of the main flow path, and a valve seat against which the check valve element can abut is formed at the axial base end of the through hole extending in the axial direction, and the check valve element is movable between a check position in which it abuts against the valve seat to block the flow of pressure fluid from the output port toward the input port, and a first open position in which it moves from the valve seat toward the axial base end to allow the same flow.

[0012] Preferably, the rod member is movable axially within the through hole by receiving a force directed toward the check valve body, and when the seal member is moved to a residual pressure exhaust position within the connection portion, a flow of pressurized fluid is permitted from the connection portion of the main flow path toward the exhaust hole, and when the check valve body is moved to a second open position axially closer to the base end than the first open position, a flow of pressurized fluid is permitted from the secondary side toward the primary side in the main flow path, and the rod member can, by moving in the axial direction, move the seal member to the residual pressure exhaust position and at the same time move the check valve body to the second open position.

[0013] Preferably, the check valve body is provided with a first return spring for biasing the valve body toward the valve seat, and the rod member is provided with a first return spring for biasing the check valve body toward the valve seat. Tip side A second return spring is provided to bias the

[0014] Preferably, an exhaust valve chamber is formed at the axial tip end side of the through hole, A piston that can slide within the through hole is provided inside the exhaust valve chamber and divides the exhaust valve chamber into a pressure chamber and a discharge chamber, and the first body is formed with a pilot port for introducing pilot pressure into the pressure chamber, and the exhaust hole that is located between the seal member and the piston and connects the discharge chamber to the outside.

[0015] Also preferably, Pilot Check Valve further includes a piston rod disposed on the axial tip side of the rod member and movable along the through hole, and an axial base end of the piston rod is inserted into the piston so as to be movable in the axial direction, and when the piston rod is pressed from a third opening that opens at the axial tip of the first body toward the axial base end side, the piston rod presses the rod member to move it toward the axial base end side, and is capable of moving the seal member to the residual pressure release position and simultaneously moving the check valve body to the second open position.

[0016] Furthermore, preferably, when the axial direction is defined as an X-axis direction, a direction orthogonal to the X-axis direction is defined as a Z-axis direction, and a direction orthogonal to the X-axis and Z-axis directions is defined as a Y-axis direction, the first body extends in the X-axis direction, a second body extending in the Z-axis direction orthogonal to the X-axis direction and having the output port at one end is connected to a base end side of the first body in the X-axis direction, a pilot body is connected to a tip end portion of the first body in the X-axis direction and is fitted onto the first body to be rotatable about the X-axis, a connecting pipe portion is connected to a base end side of the pilot body in the X-axis direction and is fitted onto the first body to be rotatable about the X-axis, an annular body is connected to the connecting pipe portion and is rotatable about a Y-axis orthogonal to the X-axis and Z-axis, and a cylindrical connecting portion is connected to the second body to be rotatable about the Z-axis and connects a base end portion of the first body to the second body. [Effects of the Invention]

[0017] As described above, according to the present invention, a pilot check valve can be provided which, in the unlikely event that a defect occurs in the sealing ability of the valve body in the residual pressure release section, can retain the pressurized fluid sealed downstream of the check valve body by the check function of the check valve body in that position in an emergency such as a power outage. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view of a pilot check valve according to an embodiment of the present invention; FIG. [Figure 2] FIG. 2 is a side view of the pilot check valve. [Figure 3] 3 is a cross-sectional view of the pilot check valve taken along the line III-III in FIG. 2. [Figure 4] FIG. 2 is a partial perspective view of a check valve body. [Figure 5] FIG. 4 is a partial cross-sectional view of the pilot check valve in a state in which the piston rod is pressed by the pilot pressure. [Figure 6] FIG. 4 is a partial cross-sectional view of the pilot check valve in a state where the piston rod is pressed. [Figure 7] FIG. 1 is a circuit diagram of a pneumatic circuit using a pilot check valve, showing a state in which the pressure fluid is blocked. [Figure 8] FIG. 8 is a circuit configuration diagram when pressure fluid is supplied to extend the fluid pressure cylinder from the state of FIG. 7. [Figure 9] FIG. 8 is a circuit configuration diagram when pressure fluid is supplied to contract the fluid pressure cylinder from the state of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0019] A pilot check valve according to the present invention will be described below. In this embodiment, a pilot check valve having three ports, an input port, an output port, and a pilot port, and capable of retaining residual pressure in a fluid pressure cylinder will be described. In addition, the case where the pressure fluid flowing through the pilot check valve is compressed air will be described.

[0020] 1 to 6 show one embodiment of a pilot-operated check valve according to the present invention. This pilot-operated check valve 10 has an input port 11 connected to a solenoid-operated directional control valve 72, 75 (see FIG. 7), an output port 12 connected to a fluid pressure device such as a fluid pressure cylinder 80 (see FIG. 7), a main flow path 13 connecting the input port 11 and the output port 12, a check valve element 14 located midway along the main flow path 13 and allowing the flow of pressure fluid from the primary side connected to the input port 11 to the secondary side connected to the output port 12, a residual pressure exhaust flow path 15 located closer to the input port 11 than the check valve element 14, a seal member 48 movably located in the residual pressure exhaust flow path 15 and blocking the flow of pressure fluid from the output port 12 to the residual pressure exhaust flow path 15, and a pilot port 55 for introducing a pilot fluid.

[0021] The output port 12 is provided at a base end 18b in the axial direction of a body 18 that is substantially cylindrical and extends elongated along the first axis L1. body A mounting portion 24 is provided on the outer surface of the valve 18 so as to be rotatable about an axis L1, and a connecting pipe portion 23 is provided on the mounting portion 24 and protrudes in the direction of a third axis L3 that is perpendicular to the axis L1 and a second axis L2 (described later). An annular body 25 is provided on the connecting pipe portion 23 so as to be rotatable about the axis L3, and an input port 11 is provided at the tip of the annular body 25 in the extending direction. Details of the mounting portion 24, the connecting pipe portion 23, and the annular body 25 will be described later.

[0022] In addition, a substantially cylindrical check valve body 20 extending along a second axis L2 perpendicular to the first axis L1 is attached to the base end of the body 18, and the output port 12 opens to one end (lower end) in the axial direction of a main body 21 (second body) arranged inside the check valve body 20.

[0023] A connecting pipe 23 is provided in an intermediate portion of the body 18 in the axial direction L1, and is fitted onto the outer peripheral surface of the body 18. The connecting pipe 23 is formed in a cylindrical shape that protrudes from the side surface of the body 18 and extends along a third axis L3 that is perpendicular to the first and second axes L1, L2. An annular body 25 is attached to the connecting pipe 23, and the input port 11 is provided in a port block 26 connected to one end of the annular body 25.

[0024] The body 18 has a substantially cylindrical pilot body 28 that is fitted onto the tip end 18a of the body 18 and extends along the first axis L1. The pilot port 55 is provided in a port block 29 that is connected to a cylindrical port forming portion 28a formed in the pilot body 28.

[0025] The main flow path 13 is formed to extend from the input port 11 through the annular body 25, the connecting pipe portion 23, the inside of the body 18, and the check valve body 20 to the output port 12 of the main body 21. The body 18, the check valve body 20, the connecting pipe portion 23, the annular body 25, and the pilot body 28 can be formed from a metal material such as an aluminum alloy, a synthetic resin material, or the like.

[0026] The following provides a more detailed explanation of the configuration of the pilot check valve 10. First, the connecting pipe 23 has a cylindrical mounting portion 24 formed at its base end in the axial direction L3, and the mounting portion 24 is fitted onto the inner surface of the body 18 via two O-rings 24a, thereby airtightly attaching the mounting portion 24 to the body 18.

[0027] The annular body 25 is elbow-shaped and airtightly connected to a connecting pipe portion 23 provided on the side surface of the body 18 via an O-ring 25a so as to be rotatable in forward and reverse directions about the central axis (third axis L3) of the connecting pipe portion 23, and an input port 11 is formed in a port block 26 attached to the tip of the annular body 25. A second flow path hole 25b inside the annular body 25 communicates with a connecting hole 23a inside the connecting pipe portion 23. The central axis of the connecting pipe portion 23, i.e., the third axis L3, is perpendicular to both the first axis L1 and the second axis L2, and the input port 11 opens in a direction perpendicular to the third axis L3.

[0028] The body 18 is airtightly attached with its base end insertion portion 18c inserted through a seal member 31 from the open end side of the connection portion 20a that opens into the side surface of the check valve body 20, thereby closing the open end of the check valve body 20. The body 18 has a through hole 18d therein that extends in the direction of the axis L1.

[0029] The check valve body 20 has a cylindrical main body 21 whose central axis is the second axis L2, and a cylindrical connecting portion 22 fitted onto the outer periphery of the main body 21. The cylindrical connecting portion 22 is rotatably fitted onto the main body 21 via an O-ring (not shown) on its inner surface, whereby the cylindrical connecting portion 22 is connected to the main body 21 so as to be rotatable in both forward and reverse directions about the second axis L2. Therefore, the body 18, the annular body 25, the pilot body 28, etc. connected to the cylindrical connecting portion 22 can rotate relative to the main body 21 about the second axis L2.

[0030] The main body 21 is formed at one end (lower end) of the second axis L2 with a connection portion 21a for directly fitting into a mounting hole of a fluid pressure device. The output port 12 is formed inside the connection portion 21a, and the outer periphery of the connection portion 21a is provided with irregularities. The connection portion 21a may be male threaded or may be configured to be connected to the fluid pressure device via piping. The main body 21 is also formed with a second communication hole 21b extending from the output port 12 along the axis L2, and multiple branch holes 21c extending radially and communicating with the second communication hole 21b. The multiple branch holes 21c communicate with a second annular flow passage 20b formed between the inner periphery of the cylindrical connecting portion 22 and the outer periphery of the main body 21, and the second annular flow passage 20b communicates with a third communication hole 20c formed in the cylindrical connecting portion 22 of the check valve body 20.

[0031] A check valve chamber 33 is formed inside the insertion portion 18c, and is part of the through hole 18d and extends along the axial direction L1. The check valve chamber 33 communicates with the third communication hole 20c of the check valve body 20. proximal end A spring support part 34 is inserted into the spring support part 34. The spring support part 34 is formed in a cylindrical shape, and has a communicating hole 34a (second opening) formed inside it that penetrates in the axial direction L1, and a plurality of cutout holes 34b formed in the outer periphery at intervals in the circumferential direction. In addition, a step part 34c that protrudes radially outward and extends annularly is formed at the base end part in the axial direction L1 of the spring support part 34, and one end part of the first return spring 36 is engaged in a state of contact with this step part 34c.

[0032] A first annular flow passage 32 (first opening) surrounding the body 18 is formed between the inner peripheral surface of the mounting portion 24 of the connecting pipe portion 23 attached to the body 18 and the outer peripheral surface of the body 18. This first annular flow passage 32 communicates with the connecting hole 23a of the connecting pipe portion 23 and with a plurality of first communication holes 35 extending radially within the body 18. These first communication holes 35 communicate with a check valve chamber 33 adjacent to a central hole 37 (connection portion) formed in the center of the body 18 and extending in the axial direction L1. The central hole 37 constitutes a part of the through hole 18d. An annular valve seat 38 surrounding the central hole 37 is formed at the boundary between the check valve chamber 33 and the central hole 37.

[0033] Within the check valve chamber 33, the check valve element 14 is disposed so as to be displaceable along the axis L1 by being supported by a first return spring 36 attached between the check valve element 14 and a spring support portion 34. The check valve element 14 is formed with a disc-shaped valve plate portion 14a and a protrusion portion 14b protruding from the tip of the valve plate portion 14a in the direction of the axis L2, and one end of the first return spring 36 is engaged with the spring support portion 34, while the other end of the first return spring 36 is engaged with the protrusion portion 14b. The check valve element 14 opens and closes the main flow path 13 connecting the input port 11 and the output port 12 by moving the valve plate portion 14a into and out of contact with a valve seat 38, and the first return spring 36 constantly biases the check valve element 14 toward the check position (see FIG. 3) where it seats on the valve seat 38.

[0034] When pressure fluid flows in the forward direction through the main flow path 13 from the input port 11 to the output port 12, the check valve element 14 is pushed by this flow and moves to a first open position P1 (see FIG. 5) where it is separated from the valve seat 38 while compressing the first return spring 36, thereby opening the main flow path 13 and allowing the pressure fluid to flow in the forward direction. On the other hand, when pressure fluid flows in the reverse direction from the output port 12 to the input port 11, the check valve element 14 is pushed by this flow and the biasing force of the first return spring 36 and moves to a check position P2 (see FIG. 3) where it seats on the valve seat 38, closing the main flow path 13 and preventing the pressure fluid from flowing in the reverse direction. That is, this state of the check valve 14 is a "function-on" state in which the check valve element 14 can perform its original check function.

[0035] A residual pressure release valve hole 42 is formed inside the body 18. The residual pressure release valve hole 42 is part of the through-hole 18d and communicates with the central hole 37, extending toward the base end in the axial L1 direction. A push rod 45 (operating part) is housed in the residual pressure release valve hole 42 so that it can slide along the axial L1 direction. A gap 43 through which air can pass is formed between the outer surface of the push rod 45 and the inner surface of the residual pressure release valve hole 42, and this gap 43 forms a residual pressure release flow path 15 that extends along the axial L1 direction. The residual pressure release flow path 15 communicates with the central hole 37. That is, the residual pressure release flow path 15 extends from the central hole 37 toward the tip end in the axial L1 direction.

[0036] The push rod 45 has a rod portion 45a and a small-diameter, shaft-shaped pressing portion 45b extending from the base end of the rod portion 45a in the axial direction L1, and the tip of the pressing portion 45b faces the check valve body 14 within the central hole 37. A ring groove 45d (sealing portion) is formed in an annular shape at the tip of the rod portion 45a, and a seal member 48 (sealing portion) is housed in this ring groove 45d.

[0037] The seal member 48 is formed in an annular shape and has a lip portion 48a that slopes radially outward as it extends toward the tip end in the axial direction L1. The tip end of the lip portion 48a is pressed against the inner surface of the residual pressure release valve hole 42 to close the residual pressure release flow path 15 and prevent the flow of pressurized fluid from the tip end to the base end in the axial direction L1. That is, when the seal member 48 is pressed against the inner surface of the residual pressure release valve hole 42, the residual pressure release flow path 15 is blocked. When the seal member 48 is displaced as the push rod 45 moves axially toward the base end and moves to the residual pressure release position P3 where the central hole 37 is located, the lip portion 48a moves away from the axial base end of the residual pressure release valve hole 42 to open the residual pressure release flow path 15 and is housed within the central hole 37 without closing the central hole 37 and allowing the flow of pressurized fluid (see FIG. 5 ).

[0038] An annular flange 45c protruding radially outward is formed at the axially L1 tip of the rod portion 45a of the push rod 45. A spring accommodating groove 42a having an inner diameter larger than the outer diameter of the rod portion 45a is formed at the axially L1 tip of the residual pressure release valve hole 42. A radially extending annular step 42b is formed at the axially L1 base end of the spring accommodating groove 42a. A second return spring 50, a compression coil spring, is disposed between the flange 45c and the step 42b of the spring accommodating groove 42a, with the rod portion 45a inserted therethrough and accommodated in the spring accommodating groove 42a. The second return spring 50 constantly biases the push rod 45 toward the axially L1 tip. The outer diameter of the flange 45c is slightly smaller than the inner diameter of the spring accommodating groove 42a. Therefore, the flange portion 45c is movable in the spring accommodating groove 42a in the direction of the axis L1.

[0039] The pilot body 28 attached to the tip of the body 18 has a cylindrical attachment portion 28b attached to the outer peripheral surface of the base end of the body 18, and an annular port forming portion 28a protruding from the side of the attachment portion 28b. The pilot body 28 is attached to the body 18 so as to be retained and rotatable about the axis L1 by fitting an annular locking step formed on the tip of the body 18 into an annular groove formed on the inner peripheral surface of the attachment portion 28b.

[0040] A residual pressure exhaust communication hole 28c, which communicates with the residual pressure exhaust valve hole 42, is formed along the axial direction L1 on the inside of the inner circumferential surface of the mounting portion 28b. The inner diameter of the residual pressure exhaust communication hole 28c is larger than that of the residual pressure exhaust valve hole 42, and an exhaust valve chamber 30 is formed within the residual pressure exhaust communication hole 28c. A piston 51 is provided within the exhaust valve chamber 30, dividing the exhaust valve chamber 30 into a pressure chamber 30a and an exhaust chamber 30b, and is slidable within the residual pressure exhaust communication hole 28c along the axial direction L1. A gap through which air can flow is formed between the radially outer surface of the piston 51 and the inner surface of the residual pressure exhaust communication hole 28c, and this gap forms a residual pressure exhaust flow path 15 (see FIG. 5) that extends along the axial direction L1. The residual pressure exhaust flow path 15 communicates with the pressure chamber 30a and the exhaust chamber 30b.

[0041] A ring-shaped groove extending in the circumferential direction is formed on the outer peripheral surface of the piston 51, and a seal member 53 is fitted in this groove to seal between the outer peripheral surface of the piston 51 and the inner peripheral surface of the residual pressure release communication hole 28c. This seal member 53 has a lip-type structure similar to the seal member 48 described above, but differs in that the orientation of the lip portion 48a is different. The lip portion 53a of the seal member 53 is inclined radially outward as it approaches the tip side in the axial L1 direction. Therefore, the lip portion 53a prevents the flow of pressurized fluid from the tip side to the base end side in the axial L1 direction, while also preventing the flow of pressure fluid in the axial L1 direction. Base end This allows the flow of pressurized fluid from the nozzle to the tip.

[0042] A recessed groove 51a recessed toward the tip end is formed in the base end of the piston 51, and the flange portion 45c of the push rod 45 is housed in this recessed groove 51a while abutting against it. The depth of the recessed groove 51a is approximately the same as the thickness of the flange portion 45c. The base end surface of the piston 51 is formed in an annular shape around the axis L1 and extends in a direction perpendicular to the axis L1. When the base end surface of the piston 51 abuts against the tip end surface of the body 18, these surfaces abut airtightly against each other, blocking the residual pressure release flow path 15. For this reason, a notched hole 19 shown in FIG. 4 is formed in the tip end of the body 18. This notched hole 19 allows the residual pressure release flow path 15 to remain open even when the base end surface of the piston 51 abuts against the tip end surface of the body 18.

[0043] A through-hole 51b penetrating along the axis L1 direction is provided in the center of the piston 51, and the base end of the piston rod 54 is fitted into this through-hole 51b via an O-ring 54a attached to the base end of the piston rod 54 in the axis L1 direction, thereby airtightly attaching the piston rod 54 to the through-hole 51b of the piston 51. The piston rod 54 is fitted into the through-hole 51b of the piston 51 so as to be slidable in the axis L1 direction (see FIG. 5).

[0044] A cylindrical cover member 60 is attached to the residual pressure release hole 28c on the tip side of the mounting portion 28b. The cover member 60 is inserted through an opening 28e (third opening) that opens at the axial tip of the residual pressure release hole 28c and fitted into the residual pressure release hole 28c via an O-ring 61 attached to the base end of the cover member 60 in the axial L1 direction, thereby airtightly attaching it to the residual pressure release hole 28c. The cover member 60 also has multiple steps formed on its outer circumferential surface, and these steps abut against engaging steps formed on the inner surface of the residual pressure release hole 28c, thereby positioning the cover member 60 in the axial L1 direction relative to the mounting portion 28b. The cover member 60 is also attached to the mounting portion 28b in a non-detachable manner by engaging locking protrusions formed on its outer circumferential surface with engaging recesses formed on the inner surface of the residual pressure release hole 28c.

[0045] The port forming portion 28a, formed on the side surface of the mounting portion 28b, is cylindrical and extends in a direction perpendicular to the first axis L1, and the pilot port 55 is formed in a port block 29 that is inserted into an opening on one end side of the port forming portion 28a. A communication hole 28d is formed in the bottom of the port forming portion 28a, and this communication hole 28d communicates with the pressure chamber 30a. This communication hole 28d is an orifice with a reduced cross-sectional area and can increase the pilot pressure introduced into the pressure chamber 30a.

[0046] The mounting portion 28b is also formed with an exhaust hole 56 that communicates with the exhaust chamber 30b. This exhaust hole 56 exhausts air from the exhaust chamber 30b to the outside as the piston 51 moves toward the tip end in the direction of the axis L1, and can also exhaust residual pressure from the fluid pressure cylinder 80 (see FIG. 7), as will be described in detail later.

[0047] In the pilot check valve 10 configured as described above, when pilot fluid is introduced into the pressure chamber 30a from the pilot port 55, the piston 51 is pressed toward the base end in the axial L1 direction, moving the push rod 45 toward the base end against the bias of the second return spring 50. Furthermore, the tip of the push rod 45 abuts against the check valve element 14, moving the valve element 14 toward the base end in the axial L1 direction against the bias of the first return spring 36. In this state, the seal member 48 is located closer to the base end in the axial L1 direction than the central hole 37 and closes the residual pressure release flow path 15. Therefore, the check valve element 14 moves away from the valve seat 38, opening the main flow path 13, allowing the flow of pressurized fluid from the input port 11 toward the output port 12.

[0048] Next, a fluid pressure circuit in the case where a fluid pressure device (fluid pressure cylinder 80) is controlled using the pilot check valve 10 will be described.

[0049] FIG. 7 shows an example of a fluid pressure circuit for controlling a fluid pressure cylinder 80, which is an example of a fluid pressure device. In this fluid pressure circuit, pressurized fluid discharged from a pressure fluid source 71 is supplied to two solenoid directional control valves 72, 75, and pilot check valves 10a, 10b are connected between the fluid pressure cylinder 80 and the two solenoid directional control valves 72, 75, respectively. These two pilot check valves 10a, 10b have the same configuration. One of the two solenoid directional control valves 72, 75 is a directional control solenoid valve 72 that switches the extension / retraction direction of the fluid pressure cylinder 80, and the other is a pilot pressure supply solenoid valve 75 that supplies pilot pressure to the pilot check valves 10a, 10b. The directional control solenoid valve 72 is a three-position, five-port type directional control valve, and the pilot pressure supply solenoid valve 75 is a two-position, five-port type directional control valve. These solenoid valves 72 and 75 have a detent function that allows them to maintain the switching positions (101, 102, 201).

[0050] The fluid pressure circuit will be described in further detail below, but the specific configuration of the two symbolized pilot check valves 10a, 10b will be referred to in FIGS. 1 to 6.

[0051] 7, the input ports P of the directional switching solenoid valve 72 and the pilot pressure supply solenoid valve 75 are connected to a pressure fluid source 71 via a supply passage 73, the first output port A1 of the directional switching solenoid valve 72 is connected to the input port 11 of the first pilot check valve 10a via a first output passage 74, and the second output port A2 of the directional switching solenoid valve 72 is connected to the input port 11 of the second pilot check valve 10b via a second output passage 76. In addition, the output port 12 of the first pilot check valve 10a is connected to the head side port 83 of the fluid pressure cylinder 80 via a first communication passage 77, and the output port 12 of the second pilot check valve 10b is connected to the rod side port 82 of the fluid pressure cylinder 80 via a second communication passage 84.

[0052] Furthermore, the pilot port 55 of the first pilot check valve 10a is connected to the first output port B1 of the pilot pressure supply solenoid valve 75 through a first pilot supply passage 86, and the pilot port 55 of the second pilot check valve 10b is connected to the first output port B1 through a second pilot supply passage 87 and the first pilot supply passage 86. The second pilot supply passage 87 branches off from the first pilot supply passage 86 and is connected to the pilot port 55 of the second pilot check valve 10b.

[0053] 7 shows a state in which the pressurized fluid source 71 is cut off from the fluid pressure circuit, so that no pressurized fluid is supplied, the directional switching solenoid valve 72 is in its initial position occupying the neutral position 100, and the pilot pressure supply solenoid valve 75 is in its initial position occupying the first switching position 200, where no pilot pressure is supplied. At this time, the check valve bodies 14 of the first pilot check valve 10a and the second pilot check valve 10b are both in a "function-on" state in which they can perform their check function because no pilot fluid is supplied, and the seal member 48 closes the residual pressure exhaust flow path 15 (see FIG. 3). Therefore, the pressurized fluid in the head-side pressure chamber 88 and the rod-side pressure chamber 89 of the fluid pressure cylinder 80 is contained as it is, because the main flow path 13 is closed by the check valve bodies 14 of the first pilot check valve 10a and the second pilot check valve 10b.

[0054] From this state, as shown in FIG. 8, when the pressurized fluid source 71 is connected to the fluid pressure circuit and the first solenoid 72a of the direction switching solenoid valve 72 is excited and the direction switching solenoid valve 72 is switched to the first switching position 101, the pressurized fluid from the pressurized fluid source 71 is supplied to the input port P of the direction switching solenoid valve 72 through the supply path 73, and at the same time is supplied to the input port 11 of the first pilot check valve 10a through the first output path 74.

[0055] Furthermore, when the pressurized fluid source 71 is connected to the fluid pressure circuit and the first solenoid 75a of the pilot pressure supply solenoid valve 75 is excited to switch the pilot pressure supply solenoid valve 75 to the second switch position 201, the pressurized fluid from the pressurized fluid source 71 is supplied to the input port P of the pilot pressure supply solenoid valve 75 through the supply path 73, and is supplied to the pilot port 55 of the first pilot check valve 10a through the first pilot supply path 86. As a result, the first pilot check valve 10a introduces pilot fluid from the pilot port 55 into the pressure chamber 30a, moves the push rod 45 via the piston 51, and opens the main flow path 13 with the check valve element 14, thereby entering a "function-off" state (see FIG. 5).

[0056] Therefore, the pressurized fluid supplied to the input port 11 of the first pilot check valve 10a is discharged from the output port 12 through the main flow path 13 of the first pilot check valve 10a and introduced into the head side pressure chamber 88 of the fluid pressure cylinder 80.

[0057] On the other hand, in the second pilot check valve 10b, pilot fluid is supplied to the pilot port 55 from the first pilot supply passage 86 through the second pilot supply passage 87, so that the second pilot check valve 10b is set to a "function-off" state and the main flow passage 13 is set to an open state. As a result, the pressurized fluid in the rod-side pressure chamber 89 of the fluid pressure cylinder 80 is discharged to the outside through the second communication passage 84, the output port 12 of the second pilot check valve 10b, the main flow passage 13, the input port 11, the second output passage 76, and the directional switching solenoid valve 72. As a result, the fluid pressure cylinder 80 extends as shown in FIG. 8.

[0058] Next, to maintain the fluid pressure cylinder 80 in the extended state, as shown in FIG. 7 , the directional switching solenoid valve 72 is switched to the neutral position 100, and the pilot pressure supply solenoid valve 75 is switched to the first switch position 200. When the directional switching solenoid valve 72 is switched to the neutral position 100 and the pilot pressure supply solenoid valve 75 is switched to the first switch position 200, the check valve element 14 of the first pilot check valve 10a is pressed against the valve seat 38 by the pressure fluid flowing in the reverse direction and the return action of the first return spring 36, thereby closing the main flow path 13 and exhibiting a check function. As a result, the pressure fluid in the head side pressure chamber 88 of the fluid pressure cylinder 80 is contained within the head side pressure chamber 88. Furthermore, the pressure fluid in the rod side pressure chamber 89 of the fluid pressure cylinder 80 is also contained within the rod side pressure chamber 89. Therefore, the fluid pressure cylinder 80 is maintained in the extended position.

[0059] 9, when the fluid pressure cylinder 80 is to be retracted, the second solenoid 72b of the direction switching solenoid valve 72 is excited to switch the direction switching solenoid valve 72 to the second switch position 102, and the first solenoid 75a of the pilot pressure supply solenoid valve 75 is excited to switch the direction switching position to the second switch position 201. Then, the actions of the first pilot check valve 10a and the second pilot check valve 10b are reversed to those when the fluid pressure cylinder 80 is to be extended, and pressure fluid is supplied from the direction switching solenoid valve 72 to the rod side pressure chamber 89 of the fluid pressure cylinder 80 through the second pilot check valve 10b, and pressure fluid in the head side pressure chamber 88 is discharged from the first pilot check valve 10a through the first discharge port E1 of the direction switching solenoid valve 72, causing the fluid pressure cylinder 80 to retract and return to its initial position.

[0060] The above explanation is an example in which the fluid pressure circuit operates normally. However, if an abnormal situation occurs, for example, when the fluid pressure cylinder 80 is extended as shown in FIG. 8, and the power supply to the directional switching solenoid valve 72 and the pilot pressure supply solenoid valve 75 is cut off and the sealing member 48 of the first pilot check valve 10a itself develops a defect in its sealing ability and loses its check function, the supply of pilot fluid from the pilot port 55 will be stopped and the introduction of compressed fluid from the input port 11 will also be stopped. As a result, the push rod 45 will move toward the tip side in the direction of the axis L1 due to the return action of the second return spring 50 and the pressure fluid flowing through the residual pressure release path 15.

[0061] As a result, the push rod 45 is moved toward the tip side in the direction of the axis L1, and the check valve element 14 shown in Fig. 3 is pressed by the pressure fluid flowing in the reverse direction and the return action of the first return spring 36 to seat on the valve seat 38, closing the main flow path 13 and achieving a "function-on" state in which the check function is exerted. Therefore, the pressure fluid in the head-side pressure chamber 88 of the fluid pressure cylinder 80 can be contained within the head-side pressure chamber 88 as is.

[0062] Meanwhile, the second pilot check valve 10b is also de-energized, so no pilot fluid is supplied. Therefore, the push rod 45 is pushed by the return action of the second return spring 50 toward the tip end in the axial direction L1, and the check valve element 14 shown in Fig. 3 is pushed by the pressure fluid flowing in the reverse direction and the return action of the first return spring 36 to seat on the valve seat 38, closing the main flow path 13 and achieving a "function-on" state in which the check function is exercised. Therefore, the pressure fluid in the rod-side pressure chamber 89 of the fluid pressure cylinder 80 can be contained within the rod-side pressure chamber 89.

[0063] As a result, the fluid pressure cylinder 80 is held in the extended position, thereby preventing malfunction of fluid pressure equipment connected to the fluid pressure cylinder 80. Note that if a defect occurs in the sealing member 48 of the second pilot check valve 10b, or if a defect occurs in the sealing member 48 of both the first and second pilot check valves 10a, 10b, the same applies as when the sealing member 48 of the first pilot check valve 10a is damaged, and therefore a description thereof will be omitted.

[0064] As described above, the pilot check valves 10a, 10b of the present embodiment are configured so that even if a defect occurs in the sealing ability of the sealing member 48, the check valve body 14 performs the check function of closing the main flow path 13 in an emergency such as when the power supply to the directional switching solenoid valve 72 and the pilot pressure supply solenoid valve 75 is stopped, and therefore the pressure fluids (residual pressures) in the head side and rod side pressure chambers 88, 89 of the fluid pressure cylinder 80 can be maintained as they are.

[0065] Incidentally, when it is desired to exhaust the residual pressure held in the fluid pressure cylinder 80 from the fluid pressure cylinder 80, the direction switching solenoid valve 72 is switched to the neutral position 100, and the pilot pressure supply solenoid valve 75 is switched to the first switching position 200, and then, as shown in FIG. 5, each piston rod 54 of the pilot check valves 10a, 10b is pressed toward the base end side in the direction of the axis L1.

[0066] When the piston rod 54 is pressed, as shown in FIG. 6 , the piston rod 54 moves toward the base end in the axial L1 direction, and the piston 51 and the push rod 45 also move toward the base end in the axial L1 direction. The piston 51 then abuts against the axial tip of the body 18 and is prevented from moving. The push rod 45 then moves toward the base end in the axial L1 direction relative to the piston 51, causing the check valve element 14 to move via the push rod 45 to a second open position P4, which is located closer to the base end in the axial L1 direction than the first open position P1. At the same time, the seal member 48 moves toward the central hole 37. As a result, the check valve element 14 moves away from the valve seat 38 to open the main flow path 13, and the seal member 48 opens the residual pressure release flow path 15. Therefore, the output port 12 communicates with the pilot port 55 and the exhaust hole 56 through the main flow path 13 and the residual pressure exhaust flow path 15, so that the residual pressure in the head side pressure chamber 88 of the fluid pressure cylinder 80 can be discharged to the outside through the first pilot check valve 10a. Similarly, the residual pressure in the rod side pressure chamber 89 of the fluid pressure cylinder 80 can be discharged to the outside through the second pilot check valve 10b.

[0067] In the pilot check valve 10 according to this embodiment, the pilot body 28 having the pilot port 55 is rotatable about the axis L1 (X-axis) relative to the body 18, the connecting pipe portion 23 is rotatable about the axis L1 relative to the body 18, the annular body 25 is rotatable about the axis L3 (Y-axis) relative to the connecting pipe portion 23, and further, the cylindrical coupling portion 22 is rotatable about the axis L2 (Z-axis) relative to the main body 21. This increases the degree of freedom in the piping direction of the piping connected to the ports connected to these bodies. [Explanation of symbols]

[0068] 10, 10a, 10b Pilot check valve 11 Input Ports 12 output ports 13 Main channel 14 Check valve body 15 Residual pressure exhaust flow path 18 Body (1st Body) 18d through hole 28e opening (3rd opening) 30 Exhaust valve chamber 30a Pressure chamber 30b Exhaust chamber 32 First annular flow path (first opening) 34a Communication hole (second opening) 36 First return spring 37 Central hole (connection part) 45 Push rod (operating part) 45d ring groove (seal, groove) 48 Sealing material (sealing part) 50 Second return spring 51 Piston 54 Piston rod 55 Pilot Port 56 Exhaust vent L1 1st axis (X axis) P1 1st open position P2 check position P3 Residual pressure release position P4 2nd open position

Claims

1. a first body having an input port and an output port; a main flow path provided in the first body and communicating between the input port and the output port; a check valve element provided on the main flow path and allowing a flow of pressure fluid from a primary side communicated with the input port toward a secondary side communicated with the output port, A pilot check valve configured to selectively move the check valve element between a position that blocks flow from the output port toward the input port and a position that allows the flow by supplying or discharging a pilot fluid, a residual pressure exhaust flow path having one end connected to a connection portion formed on the primary side of the main flow path and the other end connected to an exhaust hole opened in the first body; a seal portion provided on the residual pressure exhaust flow path and configured to block the flow of pressure fluid from a connection portion of the main flow path toward the exhaust hole; an operating portion that can move the check valve body to a position that allows the flow of pressure fluid from the secondary side toward the primary side in the main flow path, and simultaneously move the seal portion to a position that allows the flow of pressure fluid from the connecting portion of the main flow path toward the exhaust hole in the residual pressure exhaust flow path. A pilot check valve characterized by:

2. The first body is formed in a cylindrical shape extending in the axial direction and has a base end and a tip end at opposite ends in the axial direction, A through hole extending along the axial direction is formed in the first body, the input port is in communication with a first opening that opens at an axially intermediate portion of the first body, and the output port is in communication with a second opening that opens at an axially base end portion of the first body, The check valve element is supported at an axial base end of the through hole extending in the axial direction so as to be axially movable, The operation portion is accommodated in the through hole on the axial tip side of the check valve body so as to be movable in the axial direction.

2. The pilot check valve according to claim 1.

3. the operation portion is a rod member extending along the through hole, The outer diameter of the rod member is smaller than the inner diameter of the through hole, a gap formed between an outer peripheral surface of the rod member and an inner peripheral surface of the through hole forms the residual pressure exhaust flow path; 3. The pilot check valve according to claim 2.

4. The seal portion has a groove formed in an annular shape on an outer circumferential surface of the rod member, and a seal member accommodated in the groove, The seal member is a lip-type seal member, and a lip portion of the seal member is formed so as to incline radially outward as it progresses toward the base end in the axial direction.

4. The pilot check valve according to claim 3.

5. a part of the through hole communicating between the first opening and the second opening forms a part of the main flow path, a valve seat against which the check valve element can abut is formed at a base end of the through hole extending in the axial direction; the check valve element is movable between a check position where it abuts against the valve seat to prevent the flow of pressure fluid from the output port toward the input port, and a first open position where it moves from the valve seat toward the base end in the axial direction to allow the flow.

5. The pilot check valve according to claim 4.

6. the rod member is movable in the axial direction within the through hole by receiving a force directed toward the check valve body, When the seal member is moved to a residual pressure exhaust position in the connection portion, a flow of pressurized fluid from the connection portion of the main flow path toward the exhaust hole is permitted, When the check valve element is moved to a second open position that is closer to the axial base end than the first open position, a flow of pressure fluid from the secondary side to the primary side in the main flow path is permitted. The rod member is capable of moving the seal member to the residual pressure release position and the check valve element to the second open position by moving in the axial direction.

6. The pilot check valve according to claim 5.

7. The check valve body is provided with a first return spring that biases the valve body toward the valve seat, The rod member is provided with a second return spring that biases the rod member toward the tip end in the axial direction.

7. The pilot check valve according to claim 5 or 6.

8. An exhaust valve chamber is formed at the axial tip side of the through hole, a piston slidably disposed within the through hole in the exhaust valve chamber, the piston dividing the exhaust valve chamber into a pressure chamber and a discharge chamber; The first body is formed with a pilot port for introducing a pilot pressure into the pressure chamber, and the exhaust hole is located between the seal member and the piston and communicates the discharge chamber with the outside.

7. The pilot check valve according to claim 6.

9. the pilot check valve further includes a piston rod disposed at the axial tip of the rod member and movable along the through hole, The axial base end of the piston rod is inserted into the piston so as to be axially movable relative to the piston, When the piston rod is pressed from a third opening portion that opens at the axial tip of the first body toward the axial base end side, the piston rod presses the rod member to move it toward the axial base end side, thereby moving the seal member to the residual pressure release position and simultaneously moving the check valve body to the second open position.

9. The pilot check valve of claim 8.

10. When the axial direction is defined as the X-axis direction, the direction perpendicular to the X-axis direction is defined as the Z-axis direction, and the direction perpendicular to the X-axis direction and the Z-axis direction is defined as the Y-axis direction, The first body extends in the X-axis direction, a second body extending in a Z-axis direction perpendicular to the X-axis direction and having the output port at one end thereof is connected to a base end side of the first body in the X-axis direction; a pilot body is connected to a tip end of the first body in the X-axis direction and fitted onto the first body so as to be rotatable around the X-axis; a connecting pipe portion fitted onto the first body so as to be rotatable about the X axis is connected to a base end side of the pilot body in the X axis direction, an annular body is connected to the connecting pipe portion so as to be rotatable about a Y axis perpendicular to the X axis and the Z axis; a cylindrical connecting portion that is fitted onto the second body so as to be rotatable around the Z axis and that connects a base end of the first body to the second body is connected to the second body; 10. The pilot check valve according to claim 2, wherein the valve is a pilot-operated check valve.

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