Relief valve

Abstract

To provide a relief vale capable of restraining back leakage of fluid from between a seat presser and a seat.SOLUTION: A relief valve comprises a seat 3 that is a valve body having an annular seal part 30 projecting from an annular bottom part 31, a disc 5, on which the seat is arranged, a seat presser 4 for fixing the seat, energization means 7 for energizing the disc, and a valve body 2, which is mounted to a valve space 92 of fluid equipment 9, and in which the disc to which the seat is fixed to inside by the seat presser, and the energization means are mounted. The seat presser penetrates through a center part 32 of the annular bottom part 31 of the seat, and has a small diameter part 41, on which a male screw part 41a screwed with a female screw part 51 is formed, and a large diameter part 40 coupled with the small diameter part. The large diameter part comprises an annular collar part 42 projecting in a radial direction. A contact face 42a contacting the annular bottom part of the annular collar part is inclined, so that thickness of the annular collar part becomes gradually thinner from an outside diameter to an inside diameter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a relief valve that allows a fluid to flow to the outside when abnormal pressure occurs in the fluid flowing inside a fluid device. [Background technology]

[0002] The relief valve disclosed in Patent Document 1 uses a coil spring to press a valve body holder, which holds a valve body (seat) that abuts against the valve seat, toward the valve seat. When the pressure in the flow passage on the valve seat side exceeds a predetermined pressure and exceeds the pressing force of the coil spring, the valve body separates from the valve seat, allowing the fluid to flow from the internal flow passage to the exhaust flow passage.

[0003] In this type of relief valve, the seat, which is the valve body, is held by the valve body holder, but when the pressure in the flow path becomes high and the seat separates from the valve seat, high-pressure fluid flows between the seat and the valve body holder, and in some cases the seat may rise up or come off from the valve body holder. In this case, when the pressure in the flow path returns to a predetermined pressure, the seat, which is the valve body, will not abut against the predetermined position on the valve seat. In this state, there is a problem that the fluid in the flow path always flows out into the exhaust flow path. For this reason, a method has been proposed in which the seat 300, which is the valve body, is fixed to the valve body holder (disk 500) by a seat retainer 400 as shown in FIG. 8.

[0004] The relief valve 100 shown in Figure 8(a) is arranged in a valve space 92 of a fluid device 9, and the fluid device 9 is connected to a pressure chamber 90 connected to an internal flow path (not shown) and a discharge flow path 91 that releases internal fluid to the outside when abnormal pressure occurs inside, via the valve space 92 in which the relief valve 100 is arranged.

[0005] The relief valve 100 is composed of a cylindrical valve body 2 having a plurality of notches 22 formed on the circumferential surface at one end side, a disk 500 having a seat 300 serving as a valve body fixed in a recess 50 by a seat retainer 400, a spring retainer 600 disposed on the other end side of the valve body 2 via a retaining ring 8, and a coil spring 700 disposed between the disk 500 and the spring retainer 600. The seat 300 serving as the valve body is pressed against a bottom surface 92a of the valve space 92 serving as a valve seat surface by attaching the valve body 2 to a valve space 92 of a fluid device 9, disposing the disk 500, the coil spring 700, and the spring retainer 600 inside the valve body 2, pressing the spring retainer 600 toward the seat 300, and fixing the spring retainer 600 with the retaining ring 8. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-152845 A Summary of the Invention [Problem to be solved by the invention]

[0007] Normally, when the sheet 300 is pressed against the bottom surface 92a of the valve space 92 and the pressure in the pressure chamber 90 is below a predetermined value (below the pressing force of the coil spring 700), the fluid flowing through the internal flow path of the fluid device 9 does not flow out into the exhaust flow path 91.

[0008] As shown in Fig. 8(a), the sheet 300 is an annular member having a hole in the center through which the sheet retainer 400 passes, and is composed of an annular disk portion 320 and an annular seal portion 310 formed protruding from the annular disk portion 320. The sheet retainer 400, which has a threaded portion 41 that passes through the hole of the sheet 300 and screws into a screw hole 51 of a disk 500, has an annular flange portion 410 that abuts against the annular disk portion 320 and presses the annular disk portion 320 of the sheet 300 as the threaded portion 41 screws into the annular disk portion 320. The contact surfaces 320a, 410a between the annular disk portion 320 and the annular flange portion 410 are flat and parallel to each other, and the contact form is surface contact, so there is a risk of so-called back leakage occurring, in which the fluid in the pressure chamber 90 leaks into the exhaust flow path 91 through the gap indicated by the arrow U in Fig. 8(b).

[0009] An object of the present invention is to provide a relief valve capable of suppressing back leakage of fluid from between a seat and a seat retainer that screws into a disk. [Means for solving the problem]

[0010] The valve according to the present invention, which has been made to solve the above problems, A relief valve in which a biasing means biases a seat against a valve seat formed on a peripheral edge of an open end of a pressure chamber connected to a flow path of a fluid device, and when pressure in the pressure chamber exceeds a predetermined value, the seat moves away from the valve seat against the biasing force of the biasing means to release fluid in the pressure chamber to the outside of the flow path, a seat that serves as a valve body having an annular seal portion protruding from an annular bottom portion; a disk having a recess in which the sheet is placed; a sheet holder for fixing a sheet to the disk; a biasing means for biasing the disk toward the valve seat; a valve body that is attached to a valve space connected to a pressure chamber of the fluid device and that has a disk with the seat fixed thereto by a seat presser and an urging means built therein; The sheet retainer has a small diameter portion that penetrates the central hole portion of the annular bottom portion of the sheet and has a locking portion that locks into a locking hole formed in the disk, and a large diameter portion that is connected to the small diameter portion, and the large diameter portion is provided with an annular flange portion that protrudes radially, and the surface of the annular flange portion that abuts against the annular bottom portion and the abutment surface of the annular flange portion that abuts against the annular flange portion of the annular bottom portion are non-parallel before tight assembly.

[0011] In the valve of the present invention, the contact surface of the sheet retainer that presses the sheet with the sheet and the contact surface of the sheet with the sheet retainer are non-parallel before assembly and close contact, and after assembly and close contact, a part of the contact point generates a stronger pressing force than other parts, as if it were in line contact.

[0012] In this case, the surface that abuts against the annular bottom portion of the annular flange can be made non-parallel before both sides are assembled and sealed by gradually reducing the thickness of the annular flange from the outer diameter side to the inner diameter side, and the surface that abuts against the annular flange of the sheet can be made non-parallel by gradually reducing the thickness of the annular bottom portion from the inner diameter side to the outer diameter side.

[0013] In this case, the bottom surface of the recess in the disk may be provided with a circular protrusion, or the upper end of the recess may form a circular flange facing inward, and the inner circular surface of the flange may be provided with a circular protrusion.

[0014] Furthermore, the locking hole and the locking portion may be a female threaded hole and a male threaded portion that screws into the female threaded hole, respectively.

[0015] Furthermore, in these cases, a valve body incorporating a disk with a seat fixed by a seat retainer and a biasing means may be installed in the valve space. Effect of the Invention

[0016] According to the valve of the present invention, the contact surface of the seat retainer that presses the seat with the seat is non-parallel before assembly and tight contact, and after assembly and tight contact, part of the contact area becomes like a line contact where the seat is in strong contact, resulting in the creation of areas that are strongly pressed.As a result, compared to uniform surface contact, the contact between the upper surface of the annular bottom of the seat and the annular flange of the seat retainer exhibits better sealing properties, and a relief valve can be provided that can suppress so-called back leakage. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a front cross-sectional view showing the relief valve of the present invention in a closed state. [Diagram 2] FIG. 4 is a front cross-sectional view showing the relief valve in an open state. [Diagram 3] FIG. 2 is a perspective view showing a valve body of the relief valve. [Figure 4] 1 shows the seat portion of the relief valve, where (a) is an enlarged cross-sectional view with a partial cutout showing the state immediately before the seat is attached to the disk, (b) is an enlarged cross-sectional view with a partial cutout showing the state in which the seat is fixed by a seat retainer, (c) is an enlarged cross-sectional view with a partial cutout of a modified seat portion showing the state immediately before the seat is attached to the disk, and (d) is an enlarged cross-sectional view with a partial cutout showing the state in which the seat of (c) is fixed by a seat retainer. [Diagram 5] 1A shows another modified example of the seat portion of the relief valve, in which (a) shows an example in which an annular protrusion is provided on the bottom surface of the recessed portion of the disc, and (b) shows an example in which an annular protrusion is provided on the annular flange portion facing inward at the upper end portion of the recessed portion of the disc. [Figure 6] FIG. 4 is a front cross-sectional view showing another embodiment of a relief valve of the present invention. [Figure 7] FIG. 11 is a front cross-sectional view showing still another embodiment of a relief valve of the present invention. [Figure 8] FIG. 1 is a schematic diagram of a conventional relief valve, in which (a) is a cross-sectional view of the valve attached to a fluid device, and (b) is an enlarged cross-sectional view with a partial cutaway illustrating the state of back leakage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, preferred embodiments of the valve according to the present invention will be described with reference to the drawings. The shapes of the components and their relative positions described in the examples are merely illustrative and are not intended to limit the scope of the present invention unless otherwise specified. In addition, for convenience, the directions of the components may be referred to as up, down, left, right, etc. according to the directions on the drawings, but these do not limit the scope of the present invention.

[0019] <Embodiment 1> 1 to 3 show a relief valve according to a first embodiment of the present invention. FIG. 1 is a front cross-sectional view of a relief valve 1 of the present invention. The relief valve 1 of the present invention is attached to a valve space 92 that communicates with a pressure chamber 90 branched off from an internal flow path of a fluid device 9. This valve space 92 communicates with a discharge flow path 91 in addition to the pressure chamber 90. In this relief valve 1, a biasing means 7 made of, for example, a coil spring biases a sheet 3 against a valve seat formed on the periphery of an open end of the pressure chamber 90 that is connected to the flow path of the fluid device 9, and when the pressure in the pressure chamber 90 exceeds a predetermined value, the sheet 3 moves away from the valve seat against the biasing force of the biasing means 7 to discharge the fluid in the pressure chamber 90 to a discharge flow path 91 that is outside the flow path.

[0020] This relief valve 1 comprises a seat 3 which is a valve body having a circular sealing portion 30 protruding from a circular bottom portion 31, a disk 5 which has a recess 50 for accommodating this seat 3, a seat retainer 4 which fixes the seat 3 to the disk 5, a biasing means 7 which biases the disk 5 towards the valve seat, and a valve body 2 which is attached to a valve space 92 which communicates with a pressure chamber 90 of a fluid device 9 and which incorporates the disk 5 with the seat 3 fixed thereto by the seat retainer 4 and the biasing means 7.

[0021] The seat retainer 4 of the relief valve 1 of the present invention has a small diameter portion 41 which penetrates the central hole 32 of the annular bottom portion 31 of the seat 3 and has a male thread portion 41a which screws into the female thread portion 51 formed in the disk 5, and a large diameter portion 40 which is continuous with the small diameter portion 41, and the large diameter portion 40 is provided with an annular flange portion 42 which protrudes in the radial direction, and the abutment surface 42a of the annular flange portion 42 which abuts against the annular bottom portion 31 is inclined so that the thickness of the annular flange portion 42 gradually decreases from the outer diameter side toward the inner diameter side, forming a truncated cone shape.

[0022] The procedure for assembling this relief valve 1 is to first attach the valve body 2 to the valve space 92 of the fluid device 9. At this time, in the illustrated example, the end face 21 on the side where the notched portion 22 of the valve body 2 is formed abuts against the bottom face (top face in the illustrated example) 92a of the valve space 92, but this abutment is not necessary, and the valve body 2 is fixed by screwing the male thread 23 formed on the outer periphery of the valve body 2 with a predetermined torque into the female thread 93 formed on the inner periphery of the valve space 92. At this time, the outer periphery of the other end of the valve body 2 is formed with a two-face width 25 as shown in Fig. 3, but it may be formed into a polygonal shape such as a hexagon.

[0023] Also, the valve space 92 is isolated from the outside by a seal material (e.g., an O-ring) S arranged in a seal groove 24 formed on the other end side of the male thread 23. The disk 5, which has the seat 3, which is a valve body, fixed by the seat retainer 4, the biasing means 7, and the bottom plate 6 that receives the biasing means 7 are arranged in the space 20 inside the valve body 2, and the bottom plate 6 is pressed against the seat 3 side, and the retaining ring 8 is attached to the annular groove of the space 20 to prevent the bottom plate 6 from falling out to the outside, and the protruding seal part 30 of the seat 3 is pressed against the bottom surface (top surface in the figure) 92a of the valve space 92, which is the valve seat surface. This blocks communication between the pressure chamber 90 and the valve space 92. In this embodiment, an example is shown in which the bottom plate 6 is locked by the retaining ring 8, but it is also possible to form a female thread near the open end of the space 20 inside the valve body 2 and lock the bottom plate with a set screw that screws into the female thread. In this case, the pressing force of the biasing means 7 can be adjusted, and the relief pressure can be changed as desired.

[0024] <Sheet holder> As described above, the sheet presser 4 of the present invention has a truncated cone shape in which the contact surface 31a and the contact surface 42a of the annular bottom 31 of the sheet 3 are inclined so that the thickness of the annular flange 42 gradually decreases from the outer diameter side toward the inner diameter side. As a result, as shown in Figures 4(a) to (b), the outermost periphery of the contact surface 42a of the annular flange 42 of the sheet presser 4 greatly deforms the contact surface 31a, and the contact between the sheet 3 and the sheet presser 4 changes from a surface contact where the pressure is weak and uniform to a line contact where the pressure is strong on a certain line (part of the figure P1), effectively suppressing back leakage. As shown in Figure 4(a), the contact surface 31a of the sheet 3 and the contact surface 42a of the sheet presser 4 are not parallel before assembly and adhesion. Figure 4(b) shows the state after assembly and adhesion.

[0025] Also, as shown in FIG. 4(c), the contact surface 31a of the sheet holder 4 with the annular flange 42 can be inclined so that the thickness of the annular bottom 31 gradually decreases from the inner diameter side toward the outer diameter side. In this case, when the sheet holder 4 is screwed into the disk 5, as shown in FIG. 4(d), the portion where the pressing force becomes strong is the inner diameter side P2 portion of the sheet 3. There is an advantage in that the manufacturing cost can be reduced by inclining the contact surface 31a of the sheet 3 rather than the contact surface 42a of the sheet holder 4. In FIG. 4(c), the contact surface 31a of the sheet 3 and the contact surface 42a of the sheet holder 4 are also not parallel before assembly and tight contact. FIG. 4(d) shows the state after assembly and tight contact.

[0026] <Modification> 5(a) and (b) show a modification of the first embodiment.

[0027] In Fig. 5(a), an annular protrusion 52 is formed on the bottom surface 50a of the recess 50 of the disk 5. Also, in Fig. 5(b), an annular flange 51 is formed on the upper end of the recess 50 of the disk 5 facing inward, covering the annular bottom portion 31 on the outer circumferential side of the seal portion 30 of the sheet 3, and an annular or V-shaped protrusion 53 is formed on the inner annular surface of the annular flange 51.

[0028] The annular protrusions 52 and 53 bite into the contact surface with the bottom surface 50a of the recess 50 of the sheet 3, and even if there is some leakage from the contact surface 31a of the sheet 3 and the surface 42a of the sheet retainer 4, the protrusions 52 and 53 prevent leakage into the discharge flow path 91. Note that a plurality of protrusions 52 and 53 may be provided on the same plane.

[0029] <Embodiment 2> FIG. 6 shows a relief valve 1A according to a second embodiment of the present invention.

[0030] This relief valve 1A is similar to the first embodiment except for the shape of the valve body 2 and the configuration of the valve space 92 of the fluid device 9, and therefore a description thereof will be omitted.

[0031] <Valve body> In the first embodiment, the interior 20 of the valve body 2 was a through hole, but in this embodiment, it is cylindrical with a bottom, and one end side of the end face 21 where the cutout portion 22 is formed has the same shape, but the other end side is not through and forms a flange 26, and this flange 26 has a bolt mounting hole 26a opening in it to align with a screw hole 94 formed near the open end of the valve space 92 of the fluid device 9.

[0032] A seal groove 27 is formed on the outer circumferential surface of the valve body 2, and a seal material S, such as an O-ring, is attached to isolate the valve space 92 from the outside. The valve body 2 is fixed by screwing a fastening means 8, such as a hexagon socket head bolt, from the bolt mounting hole 26a into the screw hole 94.

[0033] Since the valve body 2 is not attached to the valve space 92 of the fluid device 9 by screwing it (if the seat 3 is attached and then screwed, the sealing portion 30 of the seat 3 will come into sliding contact with the bottom surface 92a (top surface in the illustrated example) of the valve space 92 which serves as the valve seat, which could degrade the seat performance), the seat 3 can be attached to the internal space 20 of the valve body 2 with the disk 5 fixed to the recess 50 by the seat retainer 4 and the biasing means 7 consisting of a coil spring or the like already in place, and no bottom plate or retaining ring is required, thereby reducing the number of parts.

[0034] <Embodiment 3> FIG. 7 shows a relief valve 1B according to a third embodiment of the present invention.

[0035] Unlike the above-mentioned embodiment, this relief valve 1B does not have the disk 5 to which the seat 3 is fixed by the seat holder 4 and the valve body 2 to which the biasing means 7 is built, and the bottom plate 6 to which the respective members and the biasing means 7 are received is directly arranged in the valve space 92 of the fluid device 9, and a retaining ring 8 is attached to a groove 95 formed in the vicinity of the open end of the valve space 92, so that the disk 5 to which the seat 3 is fixed by the seat holder 4, the biasing means 7, and the bottom plate 6 are held in the valve space 92. A seal material (e.g., an O-ring) S is arranged on the peripheral surface of the bottom plate 6 to isolate the valve space 92 from the outside. In addition, a male thread is not formed on the small diameter part of the seat holder 4, and the seat 3 is fixed to the disk 5 by forming an engagement part 43 that is press-fitted into the engagement hole 54 of the disk 5. It goes without saying that the configuration in which the seat holder 4 is press-fitted into the disk 5 can be applied to the first and second embodiments. In addition, it is also possible to eliminate the locking portion 43 of the sheet holder 4, provide a hole in the center of the sheet holder 4, form a cylindrical portion in the center of the disk 5 that is inserted into the hole, and fix the sheet 3 by crimping the tip of the cylindrical portion.

[0036] In the third embodiment, the valve body is omitted, which contributes to a significant reduction in the cost of the device. Also, the seat holder 4 is press-fitted into the disk 5, which omits the formation of a screw portion and reduces costs. [Industrial Applicability]

[0037] The relief valve of the present invention can suppress back leakage while preventing the sealing member from falling off, and can therefore be suitably used as a device for discharging fluid to the outside when abnormal pressure occurs in the fluid flowing through a wide range of fluidic devices. [Explanation of symbols]

[0038] 1 Relief valve 2 Valve body 20. Interior Space 22 Notch 3 Sheets 30 Seal part 31 Circular bottom 32 Center hole 4 Sheet holder 42 Annular flange 5 Disc 50 Recess 51 Flange 52 Circular protrusion 53 Circular protrusion 6 Bottom plate 7. Actuating means 9 Fluid equipment 90 Pressure Chamber 91 Exhaust flow path 92 Valve space

Claims

1. A relief valve in which a biasing means biases a seat against a valve seat formed on a peripheral edge of an open end of a pressure chamber connected to a flow path of a fluid device, and when pressure in the pressure chamber exceeds a predetermined value, the seat moves away from the valve seat against the biasing force of the biasing means to release fluid in the pressure chamber to the outside of the flow path, a seat that serves as a valve body having an annular seal portion protruding from an annular bottom portion; a disk having a recess in which the sheet is placed; a sheet holder for fixing a sheet to the disk; a biasing means for biasing the disk toward the valve seat, A disk having the seat fixed by a seat presser and a biasing means are installed in a valve space connected to a pressure chamber of the fluid device, The seat retainer has a small diameter portion that penetrates a central hole portion of the annular bottom portion of the seat and has a locking portion that locks into a locking hole formed in the disk, and a large diameter portion that is connected to the small diameter portion, and the large diameter portion is provided with an annular flange portion that protrudes radially, and a surface of the annular flange portion that abuts against the annular bottom portion and a contact surface of the annular flange portion that abuts against the annular flange portion of the annular bottom portion are non-parallel to each other before tightly assembled.

2. 2. The relief valve according to claim 1, wherein a thickness of the surface of the annular flange that abuts against the annular bottom portion is gradually reduced from an outer diameter side toward an inner diameter side.

3. 2. The relief valve according to claim 1, wherein a thickness of the annular bottom portion of the seat that abuts against the annular flange portion is gradually reduced from an inner diameter side toward an outer diameter side.

4. 4. The relief valve according to claim 1, wherein a bottom surface of the recess of the disk is provided with an annular protrusion.

5. 5. The relief valve according to claim 1, wherein the disk has an inwardly directed upper end portion of a circular flange, and the inner circular surface of the flange is provided with a circular protrusion.

6. 6. The relief valve according to claim 1, wherein the locking hole and the locking portion are a female threaded hole and a male threaded portion that screws into the female threaded hole, respectively.

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