check valve device

Abstract

To provide a check valve device having such a structure that pressure fluid hardly leaks out of a flow passage blocked by a valve.SOLUTION: A flow passage (2) is formed in a block (1), and a main valve (3) and an auxiliary valve (4) are provided in series in the halfway of the flow passage (2). A primary side chamber (5), an intermediate chamber (7), and a secondary side chamber (6), constituting a part of the flow passage (2), are formed in order from one end side to the other end side of the flow passage (2). A pilot valve (60) is operated to open the main valve (3) and the auxiliary valve (4).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a check valve device, and more particularly to a technique for a check valve device that is forcibly opened by a pilot valve. [Background technology]

[0002] A conventional check valve device of this type is described in Patent Document 1 (Japanese Utility Model Application Laid-Open Publication No. 52-116722). This conventional technology is configured as follows. An accommodating hole is formed in the block in the vertical direction. A cylindrical main valve member is inserted into the accommodating hole so as to be movable in the vertical direction. A main valve seat is formed circumferentially on the inner peripheral wall of the accommodating hole. A main valve surface capable of abutting against the main valve seat is formed circumferentially on the lower end of the main valve member. A main valve seat is formed circumferentially on the inner peripheral wall of the accommodating hole in the cylindrical hole of the main valve member, and a main valve surface capable of abutting against the main valve seat is formed on the main valve member. The cylindrical hole of the main valve member has a large diameter hole and a small diameter hole that pass through it in order from the top. A sub-valve member is inserted into the large diameter hole so as to be movable in the vertical direction. A sub-valve seat is formed on the peripheral edge of the small diameter hole on the large diameter hole side. A sub-valve surface is formed circumferentially on the lower end of the sub-valve member so as to be able to abut against the sub-valve seat. A valve-closing spring is attached between the sub-valve member and the block, and the valve-closing spring urges the sub-valve member toward the sub-valve seat, and the main valve member, pushed by the sub-valve member, is urged toward the main valve seat. A piston is movably inserted into the lower part of the housing bore, and a pilot portion protrudes upward from the piston. The upper small-diameter portion of the pilot portion is inserted into the small-diameter bore of the main valve member, allowing the pilot portion to abut against the sub-valve member. An advance spring attached to the working chamber below the piston moves the piston upward. When pressurized fluid is supplied to the working chamber above the piston, the piston retracts downward. In this check valve device, a supply / discharge passage as one end of the flow path is formed in the right wall of the block and communicates with the housing bore. Within the housing bore, the flow path branches into a first branch path and a second branch path. The first branch path is formed by the valve face and valve seat opening gap of the main valve member. The second branch path is formed by the small-diameter hole in the main valve member, the valve face and valve seat opening gap of the sub-valve member, the large-diameter hole in the main valve member, and a through-hole formed in the peripheral wall of the main valve member. The first branched passage and the second branched passage join at a supply and discharge passage formed in the left wall of the block. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 52-116722 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned prior art has the following problems. The above-mentioned flow path is divided into a first branch path and a second branch path within the block. If either the main valve that opens and closes the first branch path or the sub-valve that opens and closes the second branch path cannot close for some reason, for example, due to the presence of foreign matter such as dust, compressed air (pressurized fluid) will leak. Compared to when only one valve is provided per flow path within a block, the valve device of the prior art has two sets of valves, each for one branch path, which increases the possibility of a malfunction in which the valve cannot be closed and pressurized fluid leaks. An object of the present invention is to provide a check valve device having a structure that makes it difficult for pressurized fluid to leak from a flow path blocked by a valve. [Means for solving the problem]

[0005] In order to achieve the above object, the present invention provides a check valve device configured as follows, as shown in, for example, FIGS. 1 to 4 and 5. A main valve 3 and a sub-valve 4 are arranged in series in a flow path 2 formed in a block 1. A primary side chamber 5, an intermediate chamber 7, and a secondary side chamber 6, which constitute part of the flow path 2, are formed in this order from one end to the other end of the flow path 2. A pilot valve 60 opens and closes the main valve 3 and the sub-valve 4. The main valve 3 connects and disconnects the secondary side chamber 6 and the intermediate chamber 7. The main valve 3 is configured as follows: A cylindrical main valve member 41 is axially movably inserted into a receiving hole 10 formed in the block 1. A main valve surface 45 is formed on the outer peripheral wall of the main valve member 41 and is able to abut against a main valve seat 46 formed circumferentially on the inner peripheral wall of the receiving hole 10. A valve-closing spring 47 biases the main valve member 41 toward the main valve seat 46. The sub-valve 4 connects and disconnects the primary side chamber 5 and the intermediate chamber 7. The sub-valve 4 is configured as follows. A sub-valve member 50 is inserted into a cylindrical bore 48 of the main valve member 41 so as to be axially movably, and faces the main valve member 41 with a predetermined gap in the axial direction so as to be able to abut against the main valve member 41. A sub-valve surface 55 is formed on the outer peripheral wall of the sub-valve member 50, and is able to abut against a sub-valve seat 56 formed circumferentially on the inner peripheral wall of the accommodating hole 10. The pilot valve 60 has a pilot valve member 63. The pilot valve member 63 is inserted into the block 1 so as to be movably toward the sub-valve member 50, and faces the sub-valve member 50 with a predetermined gap in between. The pilot valve member 63 is urged in a direction away from the sub-valve member 50 by a retraction spring 66 mounted in the accommodating hole 10, and is moved toward the sub-valve member 50 by pressurized fluid supplied to an operating chamber 76 provided in the block 1.

[0006] The present invention has the following advantages. In the above check valve device, the main valve and the sub-valve are provided in series in one flow path. Therefore, the pressurized fluid in the secondary chamber is blocked by the main valve and the sub-valve. Therefore, even if one of the main valve and the sub-valve cannot close for some reason, the other valve closes, preventing the pressurized fluid from leaking from the secondary chamber. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view of a check valve device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram similar to FIG. 1 illustrating the operation of the check valve device. [Figure 3] FIG. 3 is a diagram similar to FIG. 1 illustrating the operation of the check valve device. [Figure 4] FIG. 4 is a diagram similar to FIG. 1 illustrating the operation of the check valve device. [Figure 5] FIG. 5 is a view similar to FIG. 4 showing a check valve device according to a modification of the above embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described below with reference to FIGS. The check valve device of the present invention includes a rectangular metal block 1 and a flow path 2 for supplying and discharging compressed air (pressure fluid). A main valve 3 and a sub-valve 4, which open and close the flow path 2, are arranged in series along the flow path 2. A primary chamber 5, an intermediate chamber 7, and a secondary chamber 6 are formed in this order from one end to the other end of the flow path 2 to form part of the flow path 2. The primary chamber 5 is connected to a compressed air source that supplies the compressed air (pressure fluid). The secondary chamber 6 is connected to a working chamber of an actuator. The main valve 3 connects and disconnects the secondary chamber 6 from the intermediate chamber 7. The sub-valve 4 connects and disconnects the primary chamber 5 from the intermediate chamber 7. As a result, all of the compressed air supplied from the compressed air source to the primary chamber 5 flows into the intermediate chamber 7 through the valve-open gap of the sub-valve 4, and the compressed air in the intermediate chamber 7 is supplied to the working chamber of the actuator through the valve-open gap of the main valve 3 and the secondary chamber 6.

[0009] In the check valve device described above, even if compressed air leaks from either the main valve 3 or the sub-valve 4 due to some cause, such as the presence of foreign matter such as dust, when compressed air is supplied from the compressed air source to the primary side chamber 5 and then the supply is stopped, the other valve is closed, so the structure is such that compressed air can be prevented from leaking out of the secondary side chamber.

[0010] As shown in FIGS. 1 to 4, the check valve device is configured as follows. An accommodation hole 10 is formed in a rectangular metal block 1 (made of iron in this embodiment) so as to penetrate in the left-right direction. An annular step 11 is formed on the inner peripheral wall near the center of the accommodation hole 10, and a cylindrical primary filter 12 is inserted from the left so as to fit closely against the step 11. The primary filter 12 has an inner cylinder 13, an outer cylinder 14, a wire mesh 15 sandwiched between the inner cylinder 13 and the outer cylinder 14, and U-shaped fixtures 16 that grip the right end of the inner cylinder 13, the right end of the outer cylinder 14, and the left end of the inner cylinder 13, the left end of the outer cylinder 14, respectively.

[0011] A cylindrical member 21, which is in close contact with the left end of the primary filter 12 via a sealing member 20, is hermetically inserted into the accommodation hole 10. The cylindrical member 21 has four holes, a first hole 22 to a fourth hole 25, formed in order from the left, and the diameters of the first hole 22 to the fourth hole 25 decrease in order from the first hole 22. A secondary filter 30, which is in close contact with an annular step 29 between the first hole 22 and the second hole 23, is inserted into the first hole 22. An annular gap 31 is formed between the outer peripheral surface of the secondary filter 30 and the inner peripheral surface of the first hole 22. The secondary filter 30 has the same configuration as the primary filter 12.

[0012] A left cover member 32 that engages with the left end of the tubular member 21 is hermetically inserted into the accommodation hole 10, and the left cover member 32 is prevented from coming out of the accommodation hole 10 by a retaining ring 33. The left cover member 32 has a base portion 34 that is hermetically inserted into the accommodation hole 10, and a tubular portion 35 that protrudes to the right from the base portion 34. The right wall of the base portion 34 is hermetically sealed to the left end of the secondary-side filter 30 via a ring-shaped sealing member 36. Therefore, the inner space and outer space of the secondary-side filter 30 are partitioned by the secondary-side filter 30, the tubular member 21, and the left cover member 34. The tubular portion 35 is inserted into a tubular hole 37 of the secondary-side filter 30 with a predetermined annular gap 38 between them.

[0013] A cylindrical main valve member 41 of the main valve 3 is slidably inserted into the cylindrical bore 39 of the cylindrical portion 35. A flange portion 42 protrudes radially outward from the right end of the main valve member 41, and a tapered portion is formed on the outer peripheral wall of the flange portion 42 so that it tapers toward the right. A circumferential groove is formed in the tapered portion, and a sealing member such as an O-ring is fitted into the circumferential groove. A main valve surface 45 is formed on the outer peripheral surface of the sealing member. The main valve surface 45 is engageable with a main valve seat 46 formed circumferentially on the inner peripheral wall of the third hole 24 of the cylindrical member 35. A valve-closing spring 47 is fitted between the main valve member 41 and the bottom wall of the cylindrical bore 39 of the cylindrical portion 35, and the valve-closing spring 47 urges the main valve member 41 rightward toward the main valve seat 46 relative to the left cover member 32.

[0014] The sub-valve member 50 of the sub-valve 4 is inserted into the cylindrical bore 48 of the main valve member 41 via a sealing member 51 so as to be axially movable in a hermetically sealed manner. A flange portion 52 protrudes radially outward from the right end of the sub-valve member 50, and a tapered portion is formed on the outer peripheral wall of the flange portion 52 so as to taper toward the right. A circumferential groove is formed in the tapered portion, and a sealing member such as an O-ring is fitted in the circumferential groove. A sub-valve surface 55 is formed on the outer peripheral surface of the sealing member. The sub-valve surface 55 is engageable with a sub-valve seat 56 formed circumferentially on the inner peripheral wall of the fourth hole 25 of the cylindrical member 21.

[0015] The cross-sectional area S of the sealing portion formed by the main valve surface 45 and main valve seat 46 of the main valve 3 is set to be larger than the cross-sectional area T of the sealing portion formed by the sub-valve surface 55 and main valve seat 56 of the sub-valve 4. Therefore, the force with which the compressed air in the secondary-side chamber 6 presses against the sealing portion of the main valve 3 in the closed state is greater than the force with which the compressed air in the secondary-side chamber 6 presses against the sealing portion of the sub-valve 4 in the closed state. The main valve member 41 is constantly pushed to the right by the valve-closing spring 47. As a result, when the force with which the compressed air in the primary-side chamber 5 presses against the sub-valve member 50 exceeds the force with which the compressed air in the secondary-side chamber 6 presses against the sub-valve member 50 while both the main valve 3 and the sub-valve 4 are closed, the sub-valve 4 opens. Compressed air flows into the intermediate chamber 7 through the valve-opening gap of the sub-valve 4. At this time, the main valve 3 is still closed. Furthermore, the volume of the intermediate chamber 7 is made smaller than those of the primary side chamber 5 and the secondary side chamber 6, thereby preventing sudden changes in pressure in the primary side chamber 5. This prevents repeated opening and closing of the sub-valve 4 due to sudden pressure changes (occurrence of chattering), and as a result, prevents wear and damage to the components of the sub-valve 4 due to chattering.

[0016] As described above, even when the pressure in the primary chamber 5 reaches the pressure value at which the sub-valve 4 opens, the main valve 3 does not open. The pressure in the primary chamber 5 continues to increase, and when it exceeds the combined force of the compressed air in the secondary chamber 6 and the biasing force of the valve-closing spring 47, the main valve 3 opens. This causes the pressurized fluid in the primary chamber 5 and the intermediate chamber 7 to flow into the secondary chamber 6 through the valve-opening gap of the main valve 3, causing a sudden drop in the pressure in the primary chamber 5, which may cause the main valve 3 to chatter. In such a case, the main valve 3 may be affected by chattering, but the sub-valve 4 is located away from the sub-valve seat 56, preventing wear and damage due to chattering.

[0017] When the sub-valve 4 and the main valve 3 are opened, the pressure difference between the primary-side chamber 5 and the secondary-side chamber 6 disappears, so the force pushing the sub-valve member 50 from the primary-side chamber 5 cancels out the force pushing the sub-valve member 50 from the secondary-side chamber 6. Similarly, the force pushing the main valve member 41 from the primary-side chamber 5 cancels out the force pushing the main valve member 41 from the secondary-side chamber 6, and only the biasing force of the valve-closing spring 47 acts on the main valve member 41. Therefore, while the compressed air passing through the valve-opening gap of the main valve 3 experiences a pressure loss corresponding to the biasing force of the valve-closing spring 47, the compressed air passing through the valve-opening gap of the sub-valve 4 experiences no or only a small pressure loss. Therefore, the pressure loss of the compressed air passing through the valve-opening gaps of the main valve 3 and the sub-valve 4 can be kept small compared to when the main valve 3 and the sub-valve 4 are each biased by a valve-closing spring.

[0018] In the check valve device, a pilot valve 60 is provided in the block for switching the sub-valve 4 and the main valve 3 from a closed state to an open state. The pilot valve 60 is configured as follows.

[0019] A cylinder bore 61 is formed by a portion of the accommodating bore 10, and the portion of the accommodating bore 10 to the right of the stepped portion 11 is the cylinder bore 61. A pilot valve member 63 is hermetically inserted into the cylinder bore 61 so as to be axially movable. The pilot valve member 63 has a main body portion 64 that is hermetically inserted into the cylinder bore 61, and an engaging portion 65 that has a smaller diameter than the main body portion 64 and protrudes leftward. The engaging portion 65 is insertable into the fourth hole 25 of the tubular member 21 and can abut against the sub-valve member 50. A retraction spring 66 is attached within the cylinder bore 61 between the right wall of the tubular member 21 and the left wall of the main body portion 64 of the pilot valve member 63. The retraction spring 66 urges the pilot valve member 63 rightward relative to the tubular member 21.

[0020] A large-diameter hole 70 constituting part of the accommodating hole 10 is formed so as to continue to the right side of the cylinder bore 61. A cylindrical filter 72 is inserted into the large-diameter hole 70 so as to fit closely to a step 71 between the large-diameter hole 70 and the cylinder bore 61. The filter 72 has a structure similar to that of the primary-side filter 12 and the secondary-side filter 30. A right-side cover member 73 is hermetically inserted into the large-diameter hole 70 so as to fit closely to the right end of the filter 72 via a sealing member, and a left-side small-diameter portion 74 of the right-side cover member 73 is inserted into the cylindrical hole of the filter 72. The right-side cover member 73 is prevented from coming off the large-diameter hole 70 by a retaining ring 75.

[0021] The main body 64 of the pilot valve member 63 is received by the right cover member 73. An operating chamber 76 is formed between the right surface of the pilot valve member 63 and the right cover member 73. A supply and discharge path 78 for compressed operating air is formed in the lower right part of the block 1 within the operating chamber 76 and communicates with an annular gap 77 formed between the outer peripheral surface of the filter 72 and the inner peripheral surface of the large diameter hole 70. Compressed air from a compressed air source is supplied and discharged through the supply and discharge path 78.

[0022] In the check valve device of this embodiment, the primary-side chamber 5 is defined by the space between the tubular member 21 and the pilot valve member 63 within the accommodating hole 10. A main valve chamber (intermediate chamber) 7 is formed within the tubular bore of the tubular member 21 so as to communicate with the sub-valve chamber 5. A primary-side supply / discharge passage 80 is formed near the center of the lower part of the block 1. The primary-side supply / discharge passage 80 communicates with an annular gap 81 formed between the inner circumferential surface of the accommodating hole 10 and the outer circumferential surface of the primary-side filter 12. The primary-side supply / discharge passage 80 is connected to a compressed air source. As a result, compressed air from the compressed air source is supplied to and discharged from the sub-valve chamber 5 through the primary-side supply / discharge passage 80, the annular space 81, and the primary-side filter 12.

[0023] A secondary supply / discharge passage 82 is formed in the upper left part of the block 1. The secondary supply / discharge passage 82 communicates with an annular gap 83 formed between the inner circumferential surface of the accommodation hole 10 and the outer circumferential surface of the tubular member 21. The annular gap 83 is also communicated with the inside of the tubular hole by a through hole 84 formed in the tubular wall of the tubular member 21. As a result, the secondary supply / discharge passage 82 communicates with the secondary chamber 6 through the annular space 83, the through hole 84, the first hole 22 of the tubular member 21, and the secondary filter 30. The secondary supply / discharge passage 82 is communicated with the working chamber of the actuator.

[0024] In this embodiment, the flow path 2 is composed of a primary supply / discharge path 80, an annular space 81, a primary chamber 5, an intermediate chamber 7, a secondary chamber 6, a through hole 84, an annular space 83, a secondary supply / discharge path 82, and the like.

[0025] As shown in FIGS. 1 to 4, the check valve device operates as follows. In the initial state (valve closed state) of FIG. 1, compressed air in the primary supply / discharge passage 80 is discharged to the outside. In addition, compressed air in the operating supply / discharge passage 78 is also discharged to the outside. Therefore, the pressure of the compressed air in the primary chamber 5, which communicates with the primary supply / discharge passage 80, is approximately atmospheric pressure. Therefore, the pressing force due to the pressure of the compressed air in the secondary chamber 6 and the biasing force of the valve-closing spring 47 move the main valve member 41 to the right, causing the main valve surface 45 of the main valve member 41 to engage with the main valve seat 46, thereby closing the main valve 3. In addition, the pressing force due to the pressure of the compressed air in the secondary chamber 6 moves the sub-valve member 50 to the right, causing the sub-valve surface 55 of the sub-valve member 50 to engage with the sub-valve seat 56, thereby closing the sub-valve 4.

[0026] When compressed air from the compressed air source is supplied to the actuator through the check valve device, the compressed air from the compressed air source first passes through the primary supply / discharge passage 80 and the primary filter 12 and is supplied to the primary chamber 5. At this time, compressed air from the compressed air source is not supplied to the operating chamber 76. Then, the pressing force of the compressed air pressure in the primary chamber 5 and the biasing force of the retraction spring 66 push the pilot valve member 63 to the right, and the pilot valve member 63 is received on the right side by the right cover member 73. The compressed air in the primary chamber 5 also pushes the sub-valve member 50 to the left. When the pressing force of the compressed air pressure in the primary chamber 5 exceeds the pressing force of the compressed air pressure in the secondary chamber 6, the compressed air in the primary chamber 5 moves the sub-valve member 50 to the left. As a result, the sub-valve face 55 is separated from the sub-valve seat 56, opening the sub-valve 4. Therefore, the compressed air in the primary chamber 5 flows into the intermediate chamber 7 through the valve opening gap. When the pushing force due to the pressure of the compressed air in the intermediate chamber 7 exceeds the resultant force of the pushing force due to the pressure of the compressed air in the secondary chamber 6 and the biasing force of the valve-closing spring 47, the compressed air in the intermediate chamber 7 moves the sub-valve member 50 and the main valve member 41 to the left. As a result, the main valve face 45 is separated from the main valve seat 46, and the main valve 3 is opened. Thus, compressed air from the compressed air source is supplied to the working chamber of the actuator through the primary chamber 5, the intermediate chamber 7, the secondary chamber 6, and the secondary supply / discharge passage 82.

[0027] When the supply of compressed air from the compressed air source is stopped, the pressing force due to the pressure of the compressed air in the secondary-side chamber 6 and the biasing force of the valve-closing spring 47 move the main valve member 41 to the right, closing the main valve 3. In addition, the pressing force due to the pressure of the compressed air in the secondary-side chamber 6 moves the sub-valve member 50 to the right, closing the sub-valve 4.

[0028] When the compressed air in the working chamber of the actuator is discharged to the outside, the compressed air in the primary side chamber 5 is discharged to the outside, and compressed air from the compressed air source is supplied to the working chamber 76 through the supply and discharge path 78 for operation and the filter 72. Then, the pushing force due to the pressure of the compressed air in the working chamber 76 moves the pilot valve member 63 to the left against the biasing force of the retraction spring 66. Next, the engaging portion 65 of the pilot valve member 63 is inserted into the cylindrical hole of the tubular member 21, pushing the sub-valve member 50 to the left and opening the sub-valve 4. Subsequently, the flange portion 52 of the sub-valve member 50 pushes the main valve member 41 to the left and opening the main valve 3. As a result, the compressed air in the working chamber of the actuator is discharged to the outside through the check valve device.

[0029] The above embodiment has the following advantages. In the check valve device described above, a main valve 3 and a sub-valve 4 are provided in series in one flow path 2. Therefore, the compressed air in the secondary chamber 6 is blocked by the main valve 3 and the sub-valve 4, and even if one of the main valve and the sub-valve cannot be closed for some reason, the other valve is closed, preventing the pressurized fluid from leaking from the secondary chamber 6.

[0030] 5 shows a modified embodiment of the present invention. In this modified embodiment, components that are the same as (or similar to) those in the above embodiment will be described with the same reference numerals as in the above embodiment.

[0031] The modified example of the above embodiment differs from the above embodiment in the following respects. As shown in Figure 5, a first supply / discharge passage 78 for actuation, which communicates with the large diameter hole 70 of the accommodating hole 10, is formed in the lower right part of the block 1. The first supply / discharge passage 78 is connected to a compressed air source. In addition, a second supply / discharge passage 87 for actuation, which communicates with the large diameter hole 70 of the accommodating hole 10, is formed in the upper right part of the block 1. The second supply / discharge passage 87 is connected to a release chamber, which is the working chamber of the actuator. In addition, a secondary supply / discharge passage 82 is connected to a lock chamber, which is the working chamber of the actuator.

[0032] When the compressed air in the lock chamber of the actuator is discharged to the outside, the compressed air in the sub-valve chamber 5 is also discharged. Compressed air from the compressed air source is supplied to the release chamber of the actuator through the first supply / discharge passage 78 for actuation, the filter 72, and the second supply / discharge passage 87, and the compressed air supplied to the actuation chamber 76 moves the pilot valve member 63 to the left. Next, the engaging portion 65 of the pilot valve member 63 is inserted into the cylindrical bore 39 of the cylindrical member 21, pushing the sub-valve member 50 to the left and opening the sub-valve 4. Subsequently, the flange portion 52 of the sub-valve member 50 pushes the tip of the main valve member 41 to the left, opening the main valve 3. This connects the secondary supply / discharge passage 82 to the primary supply / discharge passage 80 through the main valve chamber 7 and the sub-valve chamber 5. As a result, the compressed air in the lock chamber of the actuator is discharged to the outside through the flow path 2 of the check valve device.

[0033] The above embodiments can be modified as follows. The pressure fluid may be other gases or liquids such as pressure oil or water instead of the compressed air exemplified above. Of course, various other modifications can be made within the scope of what can be imagined by those skilled in the art. [Explanation of symbols]

[0034] 1: Block, 2: Flow path, 3: Main valve, 4: Sub-valve, 5: Primary side chamber, 6: Secondary side chamber, 7: Intermediate chamber, 10: Receiving hole, 41 Main valve member, 45: Main valve face, 46: Main valve seat, 47: Valve closing spring, 48: Cylindrical hole, 50 Sub-valve member, 55: Sub-valve face, 56: Sub-valve seat, 60: Pilot valve, 63: Pilot valve member, 66: Retraction spring, 76: Working chamber.

Claims

[Claim 1] A check valve device comprising: a main valve (3) and an auxiliary valve (4) arranged in series in the middle of a flow path (2) formed in a block (1); a primary side chamber (5), an intermediate chamber (7), and a secondary side chamber (6) formed in this order from one end side to the other end side of the flow path (2) so as to constitute a part of the flow path (2); and a pilot valve (60) for operating and opening the main valve (3) and the auxiliary valve (4), The main valve (3) that connects and disconnects the secondary side chamber (6) and the intermediate chamber (7) is a cylindrical main valve member (41) that is axially movably inserted into a receiving hole (10) formed in the block (1); a main valve surface (45) formed on an outer peripheral wall of the main valve member (41) so as to be able to abut against a main valve seat (46) formed circumferentially on an inner peripheral wall of the accommodation hole (10); a valve-closing spring (47) that biases the main valve member (41) toward the main valve seat (46), The sub-valve (4) connects and disconnects the primary side chamber (5) and the intermediate chamber (7), an auxiliary valve member (50) that is inserted into the cylindrical hole (48) of the main valve member (41) so as to be movable in the axial direction and that faces the main valve member (41) so as to be able to abut against it with a predetermined gap in the axial direction; a sub-valve surface (55) formed on an outer peripheral wall of the sub-valve member (50) so as to be able to come into contact with a sub-valve seat (56) formed circumferentially on an inner peripheral wall of the accommodating hole (10), The pilot valve (60) a pilot valve member (63) that is inserted into the block (1) so as to be movable toward the sub-valve member (50) and that faces the sub-valve member (50) so as to be able to abut against it with a predetermined gap, the pilot valve member (63) being urged in a direction away from the sub-valve member (50) by a retraction spring (66) that is mounted in the accommodating hole (10) and being moved toward the sub-valve member (50) by pressurized fluid supplied to an operating chamber (76) provided in the block (1).

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