Shut-off valve

Abstract

To provide a shutoff valve capable of reducing wear on a metal valve body by suppressing the pressing force of high-pressure gas and the elastic repulsive force of a spring from acting simultaneously on the valve body when the valve is shut off. [Solution] A casing (2) having a flow path (3) for a working fluid (e.g., high-pressure hydrogen gas) extending in the direction of the central axis, a valve stem (1) extending in the direction of the central axis, a valve body formed at the tip of the valve stem, a valve seat formed near the end of the flow path (3), an actuator (11) provided at the end of the casing (2) opposite the valve seat in the direction of the central axis and having the function of moving the valve stem (1) in the direction of the central axis, an elastic repulsive force eliminating device (20) having the function of eliminating the elastic repulsive force of a valve stem engagement portion operating spring (4), and a valve stem operating shaft accommodating device (40) having the function of eliminating the elastic repulsive force of a pressure adjustment spring (44).

Description

Technical Field

[0001] The present invention relates to a shut-off valve for high-pressure fluids such as high-pressure hydrogen gas, and more particularly to a shut-off valve in which a valve body and a valve seat are made of metal.

Background Art

[0002] In conventional shut-off valves for high-pressure fluids, such as high-pressure hydrogen gas, if the valve body is made of resin, the sealing performance at low pressure is good, but there is a problem in that the durability at high pressure is low. On the other hand, when a metal valve body is used, there is no problem with strength including durability, but there is a problem in that the sealing performance at low pressure is low. In order to solve the problem of sealing performance under low pressure in such a metal valve body, it is effective to press the metal valve body against the valve seat in advance by a spring. However, under high pressure, a large pressing force by the high-pressure gas and the elastic repulsive force of the spring act on the valve body at the same time, so there is a problem that the metal valve body is consumed.

[0003] As another prior art, a shut-off valve has been proposed in which the slidability, sealing performance, and durability are improved in a sliding portion (see Patent Document 1). Although such prior art (Patent Document 1) is useful, in a shut-off valve in which a metal valve body is pressed against a valve seat by a spring, it is not a technique intended to solve the problem that the pressing force by the high-pressure gas and the elastic repulsive force of the spring act on the valve body at the same time and cause it to be consumed when the valve is shut off.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] This invention was proposed in view of the problems of the prior art described above, and aims to provide a shut-off valve in which a metal valve body is pressed against a valve seat by a spring, which can reduce wear on the metal valve body by suppressing the simultaneous action of the pressing force due to high-pressure gas and the elastic rebound force of the spring on the valve body when the valve is shut off. [Means for solving the problem]

[0006] The shut-off valve (100) of the present invention is A casing (2) having a fluid channel (3) formed in which a fluid (e.g., high-pressure air, high-pressure nitrogen gas) extends in the direction of the central axis, A valve stem (1: valve shaft) is arranged within the flow path (3) and extends in the direction of the central axis, The valve body (1AT) formed at the tip of the valve stem, A valve seat (3AT) formed near the end of the flow path (3) within the casing (2), The valve closing mechanism (10) presses the valve body (1AT) against the valve seat (3AT), The valve closing mechanism (10) consists of an actuator (11) and a valve closing force adjustment mechanism (50). The valve closing force adjustment mechanism (50) comprises a pressure transmission chamber (5) and a valve stem operating shaft housing device (40). The valve stem operating shaft housing device (40) includes a valve stem operating shaft (13) that engages with the valve stem (1) and moves in the central axis direction by the actuator (11), and a pressure regulating spring (44) disposed between the valve stem operating shaft (13) and the actuator (11). The valve stem operating shaft (13) is equipped with a sealing mechanism (30) that prevents fluid from flowing into the actuator (11) side. 、 A sealing mechanism (30) is provided in the flow path (3) formed in the central axis direction of the casing (2) and in which the valve stem (1) extends, and the sealing mechanism (30) is A member (32: C-ring) formed in a C-shape by cutting out a part of the circumference of a ring, The member (33: hollow cylinder-flange composite member) has a hollow cylindrical region (33A) and a flange (33B) that extends radially outward on the valve body (1AT) side (upper side) in the central axis direction (up and down direction) of the shut-off valve 100 in the said region (33A), and the hollow cylindrical region (33A) of the member (33) having the hollow cylindrical region (33A) and flange (33B) is inserted into the central hollow portion (32A) of the C-shaped member (32). A backup ring (34) and an O-ring (35) are placed on the flange (33B). Multiple units are provided, each consisting of the C-shaped member (32: C-ring), the member (33) having a hollow cylindrical region (33A) and a flange (33B), and a backup ring (34) and an O-ring (35) placed on the flange (33B) of the member (33) having the hollow cylindrical region (33A) and flange (33B). It is characterized by the following: In the present invention, a spring can be provided between the valve stem (1) and the valve stem operating shaft (13) in the pressure transmission chamber (5).

[0007] Furthermore, in the present invention, The actuator (11) is A shaft support member (14) that engages with the valve stem operating shaft (13), A transmission member (15: fluid supply section bottom 12A, spring pressing section 16) connected to the shaft support member (14), An actuator drive fluid supply unit (12) to which actuator drive fluid (e.g., high-pressure air, high-pressure nitrogen gas) is supplied or discharged, It has a shaft support member operating spring (18) which is provided at a position opposite to the actuator drive fluid supply unit (12) and engages with the transmission member (15), Preferably, the transmission member (15) moves in the central axis direction due to the supply or discharge of drive fluid to the actuator drive fluid supply unit (12) and the shaft support member operating spring (18).

[0008] In the shut-off valve (100) of the present invention 、 before In the flow path (3) through which the valve stem (1) extends, regions (31A) with a larger inner diameter are intermittently formed at equal intervals in the axial direction, and it is preferable that the C-shaped member (32: C-ring) is fitted into these regions (31A). [Effects of the Invention]

[0009] According to the present invention having the above configuration, the actuator (11) of the valve closing mechanism (10) can seat the valve body (1AT) on the valve seat (3AT), and at that time, the elastic rebound force of the spring (4) also acts in the direction of seating the valve stem (1) on the valve seat (3AT). However, the elastic repulsive force of the spring (4) can be eliminated by the elastic repulsive force elimination device (20) of the valve closing mechanism (10), and the pressure regulating spring (44) can be eliminated by the valve stem operating shaft housing device (40). Therefore, the force for seating the valve body (1AT) at the tip of the valve stem (1) on the valve seat (3AT) is only the force transmitted from the actuator (11), and the elastic repulsive force of the pressure regulating spring (44) does not act on the valve body (1AT) by the amount of the elastic repulsive force of the spring (4) and the valve stem operating shaft housing device (40). As a result, damage to the metal valve body (1AT) and the valve seat (3AT) is reduced.

Brief Description of the Drawings

[0010] [Figure 1] It is an explanatory cross-sectional view showing the state in which the shut-off valve according to the illustrated embodiment is open. [Figure 2] It is a partial enlarged explanatory cross-sectional view of part A in FIG. 1. [Figure 3] It is an explanatory cross-sectional view showing the state immediately after the shut-off valve shown in FIG. 1 is closed. [Figure 4] It is an explanatory cross-sectional view showing the state after a predetermined time has elapsed since the shut-off valve shown in FIG. 1 is closed. [Figure 5] It is an explanatory cross-sectional view showing the seal mechanism in the illustrated embodiment. [Figure 6] It is a perspective view of the hollow cylinder / flange composite member used in the seal mechanism of FIG. 5. [Figure 7] It is a perspective view of the C-ring used in the seal mechanism of FIG. 5. [Figure 8] It is an explanatory cross-sectional view showing a modified example of the embodiment.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, referring to FIGS. 1 to 4, the shut-off valve according to the embodiment of the present invention will be described. In the illustrated embodiment, high-pressure hydrogen gas is used as the fluid, and an example of a shut-off valve used in a filling device for filling a fuel cell vehicle (FCV) with high-pressure hydrogen gas as fuel is shown. Figures 1 and 2 show the shut-off valve 100 in the open state according to the illustrated embodiment. In Figure 1, the shut-off valve 100 includes a casing 2 in which a high-pressure hydrogen gas flow path 3 extending in the central axis direction (vertical direction in Figure 1) is formed, a valve stem 1 (valve shaft) positioned within the flow path 3 and extending in the central axis direction, a valve body 1AT (tapered portion: see Figure 2) formed at the tip of the valve stem 1 (upper end of the valve stem 1 in Figure 1), a valve seat 3AT (tapered portion: see Figure 2) formed near the end of the flow path 3 within the casing 2 (lower end of the flow path 3D in Figure 2), and a valve closing mechanism 10 that presses the valve body 1AT against the valve seat 3AT. Details of part A in Figure 1, including the valve body 1AT (tapered portion) formed on the valve stem 1 and the valve seat 3AT (tapered portion) formed near the end of the flow path 3, will be described later with reference to Figure 2.

[0012] In Figure 1, the valve closing mechanism 10 includes an actuator 11 and a valve closing force adjustment mechanism 50. The actuator 11 is located near the end of the flow path 3 opposite to the valve seat 1AT in the direction of the central axis (downward in Figure 1) and has the function of moving the valve stem 1 in the direction of the central axis. The valve closing adjustment mechanism 50 includes an elastic repulsion force release device 20, a valve stem operating shaft housing device 40, and a sealing mechanism 30. The actuator 11 includes an actuator drive fluid supply unit 12 to which actuator drive fluid (e.g., high-pressure air, high-pressure nitrogen gas) is supplied or discharged, and a transmission member 15. 、The transmission member 15 has a shaft support member operating spring 18. The transmission member 15 has a fluid supply section bottom 12A and a spring pressing section 16, and has the function of supplying or discharging actuator drive fluid to the actuator drive fluid supply section 12 to the shaft support member 14 (of the valve stem operating shaft housing device 40) and converting it into movement of the shaft support member 14 in the central axis direction. Below the transmission member 15, the shaft support member operating spring 18 is positioned so as to surround the shaft 14A of the shaft support member 14, and the shaft 14A is connected to the spring pressing section 16 via a coupling section 16A. The spring 18, by its elastic rebound force, biases the shaft support member 14 upward in the central axis direction via the transmission member 15 and the shaft 14A, thereby biasing the valve stem operating shaft 13 and the valve stem 1 upward in the central axis direction. In Figure 1, the actuator drive fluid supply unit 12 is supplied with drive fluid by a supply means (not shown), and the dimension of the actuator drive fluid supply unit 12 in the central axis direction (vertical direction) is shown to be larger (compared to Figures 3 and 4). In the states shown in Figures 3 and 4, which will be described later, the drive fluid is discharged from the actuator drive fluid supply unit 12 by a discharge means (not shown), and the dimension of the actuator drive fluid supply unit 12 in the central axis direction (vertical direction) is smaller (compared to Figure 1). Reference numeral 2-3 indicates the actuator side casing.

[0013] The shaft 14A of the shaft support member 14 is positioned in the actuator-side casing 2-3. The shaft support member 14 is configured to have a larger diameter than the shaft 14A and supports the valve stem operating shaft 13. The valve stem operating shaft 13 extends in the direction of the central axis and is connected to the valve stem 1. When the shut-off valve 100 shown in Figure 1 is open, the lower end of the shaft 14A abuts against the stopper 17 at the lower end of the actuator 11. On the other hand, when the shut-off valve 100 shown in Figures 3 and 4 is closed, the lower end of the shaft 14A moves away from the stopper 17. The valve stem operating shaft housing device 40, located midway between the actuator 11 and the elastic rebound force dissipation device 20, has the upper part of the shaft support member 14, the lower part of the valve stem operating shaft 13, the valve stem operating shaft engagement portion 42 that engages with the valve stem operating shaft 13, and the pressure adjustment spring 44 arranged within a hollow housing portion 46. The base portion 13A of the valve stem operating shaft 13 is housed in the shaft support member recess 14B formed in the upper part of the shaft support member 14, thereby connecting the shaft support member 14 and the valve stem operating shaft 13. The pressure regulating spring 44 surrounds the shaft support member 14 and the base 13A of the valve stem operating shaft 13. The lower part of the pressure regulating spring 44 abuts against the bottom of the hollow housing 46, and the upper part of the pressure regulating spring 44 abuts against the valve stem operating shaft engagement portion 42.

[0014] The elastic rebound force dissipation device 20 includes a pressure transmission chamber 5, a spring 4, and a spring support member 7. The pressure transmission chamber 5 houses the end of the valve stem 1 opposite to the valve body 1AT (the lower end of the valve stem 1) and the end of the valve stem operating shaft 13 on the valve stem 1 side (the upper end of the valve stem operating shaft 13). The pressure transmission chamber 5 is provided with a valve stem engagement portion 6 that engages with the valve stem 1, and one end (upper end) of the spring 4 is attached to the valve stem engagement portion 6. The pressure transmission chamber 5 also houses a spring support member 7 that engages with the valve stem operating shaft 13, and the spring support member 7 has a flange 7A (flange of the spring support member) that can contact the other end (lower end) of the spring 4. The spring support member 7 houses the valve stem operating shaft 13's valve stem 1 side end (upper end), and the valve stem operating shaft 13 and the valve stem 1 are connected via the spring support member 7 and the valve stem engaging portion 6.

[0015] High-pressure hydrogen gas from a filling device (not shown) flows into the pressure transmission chamber 5 through the suction port 2A of the casing 2, the suction port side passage 3A (see Figure 2), and the valve operating passage 3C (see Figure 2). Therefore, the pressure of the high-pressure hydrogen gas acts on the pressure transmission chamber 5. When the pressure in the pressure transmission chamber 5 rises above a predetermined value (set on a case-by-case basis by the elastic rebound force of the pressure adjustment spring 44), the valve stem operating shaft 13 moves in a direction away from the spring 4 (downward) due to the pressure difference between the pressure transmission chamber 5 and the hollow housing 46.

[0016] In Figure 1, high-pressure hydrogen gas flows into the shut-off valve 100 from the intake port 2A and is discharged from the discharge port 2B toward the equipment downstream (FCV side). Details of the high-pressure hydrogen gas flow path 3 communicating from the intake port 2A to the discharge port 2B are shown in Figure 2, which is a partial enlargement of section A in Figure 1. In Figure 2, the metal casing 2 has a main body casing 2-1 and a discharge side casing 2-2, and the main body casing 2-1 and the discharge side casing 2-2 are connected by a casing screw portion 22. The main body casing 2-1 has a high-pressure hydrogen gas intake port 2A, which communicates with the valve operating flow channel 3C via the intake side flow channel 3A and the flow channel space 3B. The flow channel space 3B communicates with the discharge side flow channel 3D formed in the main body casing 2-1 and the discharge side flow channel 3E formed in the discharge side casing 2-2, and communicates with the high-pressure hydrogen gas discharge port 2B. A metal valve stem 1 is positioned in the hollow portion of the valve operating passage 3C and passage space 3B of the main body casing 2-1, and the tip of the valve stem 1 (upper end in Figure 2) constitutes a valve body 1AT having a tapered surface. A tapered surface is formed at the end of the discharge-side flow path 3D on the flow path space 3B side, and this tapered surface constitutes the valve seat 3AT. The valve seat 3AT and the valve body 1AT at the tip of the valve stem 1 constitute the shut-off valve. Reference numeral 23 indicates an O-ring.

[0017] In Figures 1 and 2, which show the shut-off valve in the open state, the tapered surface formed at the end of the flow path space 3B of the discharge-side flow path 3D, which forms the valve seat 3AT, is separated from the tapered surface at the tip of the valve stem 1 that constitutes the valve body 1AT. On the other hand, in Figures 3 and 4, which show the shut-off valve in the closed state, the tapered surface of the valve body 1AT is seated on the tapered surface that constitutes the valve seat 3AT. In Figure 2, when the shut-off valve is open, the high-pressure hydrogen gas supplied from the intake port 2A (arrow A1) flows into the flow path space 3B via the intake port side flow path 3A. The high-pressure hydrogen gas that has flowed into the flow path space 3B is discharged from the discharge port 2B downstream (FCV side equipment: not shown) via the discharge port side flow path 3D and the discharge port side flow path 3E formed in the discharge port side casing 2-2 (arrow A2).

[0018] For example, when changing from the closed state of the shut-off valve 100 shown in Figures 3 and 4 to the open state of the shut-off valve 100 shown in Figure 1, the actuator drive fluid is supplied to the actuator drive fluid supply unit 12 (by a supply means not shown). When drive fluid is supplied to the actuator drive fluid supply unit 12, the fluid pressure increases the dimension of the actuator drive fluid supply unit 12 in the central axis direction (vertical direction), and the bottom portion 12A of the fluid supply unit and the spring pressing portion 16 (transmission member 15) descend in the direction of arrow D against the elastic rebound force of the shaft support member operating spring 18.

[0019] Since the spring pressing portion 16 is connected to the shaft 14A of the shaft support member at the connecting portion 16A, when the spring pressing portion 16 descends, the shaft support member 14 descends in the direction of arrow D. When the shaft support member 14 descends in the direction of arrow D, the valve stem operating shaft 13, which is connected to the shaft support member 14 via the shaft support member recess 14B, also descends in the direction of arrow D. As the valve stem operating shaft 13 descends in the direction of arrow D, the valve stem 1 also descends in the direction of arrow D via the spring support member 7. As the valve stem 1 descends, the valve body 1AT (tapered surface, Figure 2) at the tip of the valve stem 1 separates from the valve seat 3AT (tapered surface, Figure 2) formed in the discharge port side flow path 3D, and the shut-off valve 100 opens.

[0020] Figure 3 shows the transition from the state in which the valve is open and high-pressure hydrogen gas is flowing (Figure 1) to the state in which the shut-off valve 100 is closed. When changing from the state in Figure 1 to the state in Figure 3, the actuator drive fluid is discharged from the actuator drive fluid supply unit 12. When the drive fluid is discharged and the pressure inside the actuator drive fluid supply unit 12 decreases, the elastic rebound force of the shaft support member operating spring 18 reduces the central axis direction (vertical direction) dimension of the actuator drive fluid supply unit 12. As a result, the bottom portion 12A of the fluid supply unit and the spring pressing portion 16 rise in the direction of arrow U.

[0021] Since the spring pressing portion 16 is connected to the shaft 14A at the coupling portion 16A, when the spring pressing portion 16 rises, the shaft support member 14 rises in the direction of arrow U. When the shaft support member 14 rises in the direction of arrow U, the elastic repulsive force of the pressure regulating spring 44 acts on the valve stem operating shaft engagement portion 42, causing the valve stem operating shaft 13 to rise in the direction of arrow U. As the valve stem operating shaft 13 rises in the direction of arrow U, the spring support member 7 presses against the spring 4 and the valve stem engagement portion 6, causing the valve stem 1 to rise. As the valve stem 1 rises, the valve body 1AT (tapered surface, Figure 2) at the tip of the valve stem 1 seats on the valve seat 3AT (tapered surface) formed in the discharge port side flow path 3D, and the shut-off valve 100 closes.

[0022] According to the shut-off valve 100 of the illustrated embodiment, after a predetermined time has elapsed from the state shown in Figure 3, the pressing force from the pressure regulating spring 44 is reduced, and the elastic rebound force of the spring 4 disappears. The mechanism will be explained with reference to Figure 4. As shown in Figure 3, even when the shut-off valve 100 is closed with the tapered surface 1AT (Figure 2) at the tip of the valve stem 1 seated on the tapered surface 3AT (valve seat: Figure 2), the high-pressure hydrogen gas flowing in from the intake port 2A flows through the intake port side passage 3A and the passage space 3B into the valve operating passage 3C. In Figure 4, which shows the state after a predetermined time has elapsed since the shut-off valve 100 was closed, the high-pressure hydrogen gas that has flowed through the valve operating passage 3C flows into the pressure transmission chamber 5. Due to the pressure of the incoming high-pressure hydrogen gas, the valve stem operating shaft 13 moves towards the hollow housing 46 side where there is no pressure. At the same time, the spring support member 7 engaged with the valve stem operating shaft 13 also descends in the direction of arrow D (the direction in which the valve body 1AT of the valve stem 1 separates from the valve body 1AT).

[0023] When the flange 7A of the spring support member 7 descends by a predetermined amount or more in the direction of arrow D, the spring 4 moves from a state in contact with the flange 7A (as shown in Figure 3) to a state separated from it, as shown in Figure 4. In other words, the spring 4, which was compressed by the rising flange 7A, is released from its compressed state and becomes extended as the flange 7A descends and separates from it. Therefore, the elastic repulsive force of the spring 4 pressing the valve stem engagement portion 6 in the direction of arrow U disappears.

[0024] As a result, the force required to close the valve is reduced by the amount of the elastic repulsive force of the spring 4, leaving only the pressure of the high-pressure hydrogen gas. In this way, by adjusting the force pressing on the valve stem 1 with the pressure of the fluid acting on it, the pressing force due to the added fluid pressure can be reduced. Therefore, it is possible to prevent a force greater than the force required to close the valve from being applied, thus reducing damage to the valve body 1AT and valve seat 3AT.

[0025] Here, the axial position of the valve stem operating shaft 13 moves due to the vertical movement of the flange 7A of the spring support member 7, but since the valve stem 1 is connected to the valve stem engagement portion 6, the vertical movement of the flange 7A of the spring support member 7 and the vertical movement of the valve stem 1 are not synchronized. Therefore, the position of the valve stem 1 in Figures 3 and 4 is the same, and the state in which the tapered surface of the valve body 1AT at the tip of the valve stem (Figure 2) is seated on the valve seat 3AT (Figure 2) is maintained. Although not shown in the diagram, it is also possible to open and close the shut-off valve using an electric motor instead of using fluid pressure.

[0026] Next, with reference to Figures 5 to 7, the sealing mechanism of the shut-off valve shown in Figures 1 to 4 will be explained. Multiple seals are necessary to prevent high-pressure hydrogen from leaking from the sliding part of the valve stem; therefore, the shut-off valves shown in Figures 1 to 4 are equipped with a sealing mechanism. In Figures 1, 3, and 4, a sealing mechanism 30 is provided at the position where the valve stem operating shaft 13 slides. In Figure 5, the sealing mechanism 30 has a structure in which multiple units combining an O-ring 35, a backup ring 34, a hollow cylindrical / flange composite member 33, and a C-ring 32 are stacked in layers. In the flow path 3 formed in the central axis direction (vertical direction) of the casing 2 (Figures 1 to 4) and through which the valve stem operating shaft 13 extends, multiple regions with a large inner diameter 31A (enlarged diameter portion) are formed intermittently at equal intervals in the central axis direction (two locations in the example of Figure 5) in the hollow portion 31 through which the valve stem operating shaft 13 slides.

[0027] The C-ring 32 in the sealing mechanism 30, which is installed in the hollow portion 31 on which the valve stem operating shaft 13 slides, has a shape in which a part of the circumference of the ring is cut out and fits into the enlarged diameter portion 31A of the hollow portion 31. A hollow cylindrical-flange composite member 33 is positioned above the C-ring 32. The hollow cylindrical-flange composite member 33 has a hollow cylindrical region 33A (main body) that extends in the central axis direction (vertical direction), and the hollow cylindrical-flange composite member 33 is inserted into the hollow portion 32A at the radial center of the C-ring 32. A flange 33B extending radially outward is formed on the main body 33A of the hollow cylindrical-flange composite member 33, and a backup ring 34 and an O-ring 35 are placed on the flange 33B. Another backup ring 34 is provided above the O-ring 35, so that the O-ring 35 is sandwiched between the two backup rings 34, 34. The sealing mechanism 30 is constructed by stacking multiple units (combination C32-35) consisting of an O-ring 35, two backup rings 34, 34, a hollow cylindrical / flange composite member 33, and a C-ring 32. Figure 5 shows a state in which combination C32-35 is stacked in two layers.

[0028] By adopting this configuration, it is possible to easily arrange multiple stages of seals and reliably prevent leakage of high-pressure hydrogen gas by forming an enlarged diameter portion 31A into which the C-ring 32 fits, without increasing the inner diameter of the portion (hollow portion) in which the valve stem operating shaft 13 slides. Furthermore, the sealing mechanism 30 can be positioned not only at the sliding position of the valve stem operating shaft 13, but also at any position where the shaft (including the valve stem 1) slides. Although not shown in the diagram, a cup seal can be used instead of the O-ring 35. In that case, it is preferable to position the cup seal so that the upper part of the cup seal is facing the open direction in Figures 1, 3, and 4.

[0029] The hollow cylindrical / flange composite member 33 and the C-ring 32 are shown in Figures 6 and 7, respectively. The backup ring 34 is made of resin and is provided to prevent the O-ring 35 from rupturing due to a portion of the O-ring 35 extending under high pressure and entering the gap with the inner wall (so-called "O-ring overhang").

[0030] The hollow cylindrical-flange composite member 33 shown in Figure 6 is made of metal and has a hollow cylindrical main body 33A that extends in the central axis direction (vertical direction) and a flange 33B (flange 33B on the upper edge of the main body 33A) located above the main body 33A and extending radially outward. When installing the sealing mechanism 30, the hollow cylindrical portion of the main body 33A is inserted into and fitted into the hollow portion 32A of the C-ring 32. This prevents the C-ring 32 from contracting radially inward. When installing the sealing mechanism 30, the backup ring 34 and O-ring 35 are placed on the flange 33B which extends radially outward.

[0031] The C-ring 32 shown in Figure 7 is made of metal and is formed in a C-shape with a portion of the annular circumference cut out, and multiple (four in the illustrated embodiment) slits 32B are formed at roughly equal intervals in the circumferential direction. By forming the slits 32B, the C-ring 32 is made more likely to expand radially outward, making it easier to insert the main body 33A of the hollow cylinder / flange composite member 33 into the hollow portion 32A in the radial center of the C-ring 32. Note that the number of slits 32B may be less than three or five or more (for example, two to six). The axial dimension TS of the C-ring 32 (vertical direction in Figures 1, 3, and 4) is set to be thicker than the radial dimension TR. The ratio of the radial dimension TR to the axial dimension TS of the C-ring 32 is set in the range of 1:1 to 1:10. This is because a thicker axial dimension TS of the C-ring 32 makes it less likely for the C-ring 32 to shrink radially. The axial dimension TS of the C-ring 32 is set to a value that can withstand the shear force acting in the axial direction. At the cut 32B, the radial thickness of the C-ring 32 is reduced. As described above, the main body 33A of the hollow cylindrical-flange composite member 33 is inserted into the hollow portion 32A of the C-ring 32, and the flange 33B of the hollow cylindrical-flange composite member 33, which is positioned adjacent to the upper part of the C-ring 32, covers the C-ring 32. Therefore, even if the radial thickness is reduced due to the cut, there is no risk of the function of the sealing mechanism 30 being impaired.

[0032] Figure 8 shows a modified example of the embodiment described in Figures 1 to 7. In the shut-off valve 100 of the embodiment shown in Figures 1 to 7, a spring 4 is provided in the pressure transmission chamber 5, but in the modified example shown in Figure 8, no spring is provided. In the modified example shown in Figure 8, although the spring 4 is not provided, fluid pressure is applied to the pressure transmission chamber 5-1 when fluid flows into the shut-off valve 100 because of the presence of the sealing mechanism 30. Since fluid pressure is applied to the upper part of the valve stem operating shaft 13 that presses against the valve stem 1, a counterforce is applied to the pressure regulating spring 44, which can reduce the pressing force on the valve stem 1. Therefore, the pressing force on the valve stem 1 does not become an excessive pressing force due to the addition of fluid pressure to the pressure from the actuator 11, thus preventing damage to the valve seat 3AT and valve body 1AT. The other configurations and effects of the modified example in Figure 8 are the same as those of the embodiments in Figures 1 to 7.

[0033] The illustrated embodiments are for illustrative purposes only and are not intended to limit the technical scope of the present invention. [Explanation of Symbols]

[0034] 1. Valve stem 1AT... Valve body 2. Casing 3...flow channel 3AT...Valve seat 4. Spring 5, 5-1... Pressure transmission chamber 6. Valve stem engagement section 7. Spring support member 7A...Flange (Flange of spring support member) 10. Valve closing mechanism 11. Actuator 12. Fluid supply unit for actuator drive 12A...Bottom of fluid supply section 13. Valve stem acting shaft 14. Shaft support member 15. Transmission member 16. Spring pressing section 20. Elastic rebound force elimination device 30. Seal mechanism 31A... Region with a large inner diameter in the flow path 32. C-shaped component (C-ring) 32A···Hollow part of C ring 32B...C-ring break 33. Hollow cylinder-flange composite member 33A...Hollow cylindrical region (main body) of hollow cylinder / flange composite member 33B...Flange of hollow cylindrical-flange composite member 34... Backup ring 35···O-ring 40. Valve stem acting shaft housing device 50... Valve closing force adjustment mechanism 100...Shut-off valve

Claims

1. A casing in which a fluid channel extending in the direction of the central axis is formed, A valve stem is disposed within the aforementioned flow path and extends in the direction of the central axis, The valve body formed at the tip of the valve stem, A valve seat formed near the end of the flow path within the casing, The valve closing mechanism has a valve body that presses against the valve seat, The valve closing mechanism consists of an actuator and a valve closing force adjustment mechanism. The valve closing force adjustment mechanism comprises a pressure transmission chamber and a valve stem operating shaft housing device. The valve stem operating shaft housing device includes a valve stem operating shaft that engages with the valve stem and moves in the central axis direction by the actuator, and a pressure regulating spring disposed between the valve stem operating shaft and the actuator. The valve stem operating shaft is equipped with a sealing mechanism that prevents fluid from flowing into the actuator side. A sealing mechanism is provided in the flow path formed in the central axis direction of the casing and in which the valve stem extends, and the sealing mechanism is, A member formed in a C-shape by cutting out a part of the circumference of a ring, The member has a hollow cylindrical region and a flange that extends radially outward on the valve body side in the central axis direction of the region, and the hollow cylindrical region of the member with the flange is inserted through the central hollow portion of the C-shaped member. A backup ring and an O-ring are placed on the flange. A shut-off valve characterized by having multiple stages of combinations consisting of the C-shaped member, the member having a hollow cylindrical region and a flange, and a backup ring and O-ring placed on the flange of the member having the hollow cylindrical region and flange.

2. The shut-off valve according to claim 1, wherein a spring is provided between the valve stem and the valve stem operating shaft in the pressure transmission chamber.

3. The actuator is A shaft support member that engages with the valve stem operating shaft, A transmission member connected to the shaft support member, An actuator drive fluid supply unit to which actuator drive fluid is supplied or discharged, It has a shaft support member operating spring that is provided at a position opposite to the actuator drive fluid supply unit and engages with the transmission member, The shut-off valve according to either claim 1 or 2, wherein the transmission member moves in the central axis direction due to the supply or discharge of drive fluid to the actuator drive fluid supply unit and the shaft support member operating spring.

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