Flow control valve

Abstract

To provide a flow control valve that handles high-pressure gas as the working fluid, is capable of operating under the high-pressure load of the high-pressure gas, and is resistant to wear. [Solution] The flow control valve (100) of the present invention comprises a cam plate (11) with an inclined surface, a drive source (20) that rotates the cam plate, a cam follower (12) that has a cam follower roller (12A) pressed against the surface of the cam plate and moves in the direction of the central axis of the flow control valve due to the inclination of the cam plate, and a valve stem support (13). The cross-sectional area of ​​the flow path and the flow rate vary depending on the insertion dimension (Lt) of the valve stem (1) into the flow path (3). The cam follower is rod-shaped overall, with the cam follower rollers provided near both ends. The thickness dimension of the cam plate (11) is small in the radially outward direction and large in the radially inward direction. The cam follower roller (12A) is frustoconical, and the inclined surface of the cam plate has a shape complementary to the frustoconical portion of the cam follower roller.

Description

Technical Field

[0004] , , , , , , ,

[0001] The present invention relates to a flow control valve, for example, a flow control valve for high-pressure gas of the needle valve type.

Background Art

[0002] As a flow control valve for high-pressure gas, there is a type in which the valve body of the high-pressure gas control valve reciprocates in the axial direction of the shaft to adjust the valve opening degree. In such a conventional flow control valve, there are those in which the valve body or the shaft is actuated by an actuator such as a stepping motor (for example, Patent Document 1), and those in which an air valve is provided separately and actuated by air. However, in the case of a flow control valve for high-pressure gas, since the pressure of the high-pressure gas as the working fluid acts on the valve body, it is necessary to operate with a large load to reciprocate the valve body, and there is a problem that the actuator or the air valve itself becomes large. In addition, there is a problem that equipment for controlling the large actuator or the air valve itself is required.

[0003] Here, by using a rotary device such as a motor as a power source and converting the rotary motion into a linear motion by a screw mechanism, it is possible to reciprocate the valve body in the axial direction of the shaft to adjust the valve opening degree. And if a motor is used as the power source, it is possible to directly control the valve opening degree by controlling the motor. However, in order to convert the rotary motion into a linear motion by the screw mechanism, the pressure of the high-pressure gas as the working fluid acts on the screw thread of the screw mechanism, resulting in wear of the screw engagement part and a problem with durability.

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 flow control valve that handles high-pressure gas as a working fluid, which can withstand the load caused by the high pressure of the high-pressure gas and is less prone to wear. [Means for solving the problem]

[0006] The flow control valve (100) of the present invention is A cam plate (11) having a slope formed on its surface (cam surface 11A), A drive source (20: for example, an electric motor) rotates the cam plate (11) via a reduction mechanism (21), A cam drive (12: cam drive rod) has a rotating part (12A: roller or bearing) that is pressed against the surface (11A: cam surface) of the cam plate (11), and moves in the direction of the central axis (C) of the flow control valve (100) (or valve stem 1) due to the inclination of the surface (11A) of the cam plate (11), It has a valve stem support portion (13) which has one end connected to a cam follower (12) and the other end connected to a valve stem (1), The cross-sectional area and flow rate of the flow path vary depending on the dimension (Lt) to which the valve stem (1) is inserted into the flow path (3: small diameter section 3A and large diameter section 3B). The cam follower (12) is configured as a rod, and cam follower rollers (12A) are provided near both ends that are rotatably pressed against the surface (11A) of the cam plate (11). The cam plate (11) is characterized by having a small thickness dimension in the radially outward direction (direction of arrow SU) and a large thickness dimension in the radially inward direction, having an inclination on the side (front or upper) of the cam plate (11) on which the cam follower (12) rolls (the front or upper side), having a frustoconical shape at the part of the cam follower roller (12A) that contacts the cam plate (11), and having a shape complementary to the frustoconical portion of the cam follower roller (12A).

[0007] In the present invention, it is preferable that the frustoconical portion of the cam-driven roller (12A) is set such that the point (VT) where the extensions of the edges of the frustoconical shape intersect is the rotation center (RC) of the cam plate (11).

[0008] Furthermore, in the present invention, it is preferable that a measuring device (22) is provided for measuring the amount of rotation of the output shaft of the drive source (20: motor) or the amount of rotation of the gears constituting the reduction mechanism (21), and a control device (control unit CU: see Figure 16) is provided for controlling the flow rate of the flow control valve (100) based on the measurement results of the measuring device (22).

[0009] In the flow control valve (100) of the present invention, a valve stem (1) with a small diameter tip (1A) and a main body (2) having a flow path (3) formed therein are provided, wherein the valve stem tip (1A) is positioned to be insertable into the small diameter portion (3A) of the flow path (3) formed in the main body (2), and a gap (δ) exists between the outer circumference of the valve stem tip (1A) and the inner circumferential surface of the small diameter portion (3A) of the flow path, and it is preferable that the valve opening or flow rate fluctuates depending on the position of the valve stem (1) in the direction of the central axis (C) with respect to the flow path (3). [Effects of the Invention]

[0010] According to the present invention having the above configuration, when the rotation of the drive source (20: electric motor) is transmitted to the cam plate (11) via the reduction mechanism (21), the cam plate (11) rotates. Since a slope is formed on the surface (11A: cam surface) of the cam plate (11), the driven element (12: cam driven rod) that is pressed against and in contact with the cam surface (11A) moves in the direction of the central axis (C) due to this slope. As a result, the valve stem (1) and valve body (1AT) connected to the cam driven element (12) also move in the direction of the central axis (C), and the dimension (Lt) into which the valve stem (1) is inserted into the flow path (3: small diameter flow path 3A and large diameter flow path 3B) changes, causing the flow path cross-sectional area and flow rate to change. By controlling the rotation angle of the cam plate (11) and thereby controlling the circumferential position of the cam plate surface (11A) that contacts the cam follower (12), the central axis (C) position of the cam follower (12) in contact with the cam surface (11A) can be adjusted. As a result, the position of the valve stem (1) in the flow path (3) changes, the dimension (Lt) to which the valve stem (1) is inserted into the flow path (3) changes, and the flow path cross-sectional area and flow rate change. In other words, the rotation of the cam plate (11) adjusts the position of the valve stem (1) in the direction of the central axis (C), and the dimension (Lt) to which the valve stem (1) is inserted into the flow path (3) is adjusted, thereby controlling the flow path cross-sectional area and flow rate.

[0011] In this invention, a cam plate (11) rotates using a rotating device such as a drive source (20) as a power source, and a cam follower (12) moves in the direction of the central axis (C) by the cam plate (11). By converting rotational motion into linear motion, the valve body (1AT) is made to reciprocate in the direction of the valve stem (1) axially, thereby adjusting the valve opening. Furthermore, if a motor (20) is used as the drive source, the valve opening can be directly controlled by controlling the motor (20). Furthermore, according to the present invention, the screw mechanism does not convert rotational motion into linear motion, and the pressure of the working fluid, which is high-pressure gas, does not act on the screw threads of the screw mechanism. Therefore, wear on the screw threads does not occur, and the durability of the flow control valve is improved.

[0012] As mentioned above, in flow control valves for high-pressure gases such as high-pressure hydrogen gas, the pressure of the high-pressure gas acts on the valve body, and conventionally, a large actuator or air valve was required to move the valve body back and forth. According to the present invention, by appropriately arranging bearings or rollers to reduce resistance, the cam plate (11) can be rotated without using a large amount of power, and the position of the valve stem (1) in the direction of the central axis (C) can be adjusted. Therefore, there is no need to provide a large actuator or air valve as in the conventional technology. Furthermore, by measuring the amount of rotation of the motor (20), which is the drive source, or the amount of rotation at a predetermined point in the reduction mechanism, the positions of the cam surface (11A) and the cam follower (12) can be identified. Additionally, by controlling the amount of rotation of the motor (20) or the amount of rotation at a predetermined point in the reduction mechanism (21), the axial (C) position of the valve stem (1) can be accurately controlled, making it possible to accurately control the flow rate of high-pressure gas according to the required characteristics.

[0013] In the present invention, the thickness dimension of the cam plate (11) in the radially outward direction (dimension in the direction of arrow SU) is small, and the thickness dimension in the radially inward direction is large. The surface (11A) of the cam plate (11) on the side (front side or upper side) where the cam follower (12) rolls is inclined, and the portion of the cam follower roller (12A) that contacts the cam plate (11) is configured in the shape of a frustocone. The inclined surface of the cam plate (11) is complementary in shape to the frustocone portion of the cam follower roller (12A). As a result, when the cam follower roller (12A) rotates along the surface (11A) of the cam plate in a circular trajectory, the difference in inner wheel size is eliminated, and slippage does not occur. This prevents wear on the cam follower roller (12A). [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view illustrating a flow control valve according to an embodiment of the present invention. [Figure 2] This characteristic diagram shows the desirable flow control valve opening-hydrogen flow rate characteristics for hydrogen refueling of FCVs. [Figure 3] This is an enlarged explanatory cross-sectional view showing the relative position of the shaft tip and the small-diameter flow path portion when the flow control valve according to the illustrated embodiment is closed. [Figure 4] This is an enlarged explanatory cross-sectional view showing the relative position between the shaft tip and the small-diameter flow path of the flow control valve in the low-flow region. [Figure 5] This is an enlarged explanatory cross-sectional view showing the relative position of the shaft tip and the small-diameter section of the flow path at the boundary between the low-flow region and the high-flow region of the flow control valve. [Figure 6]It is an enlarged explanatory cross-sectional view showing the relative position between the tip of the shaft and the small-diameter part of the flow path in the state of the large flow rate region of the flow rate adjustment valve. [Figure 7] It is a perspective view of the flow rate adjustment valve shown in FIG. 1. [Figure 8] It is a perspective view showing the omission of the casing in FIG. 7. [Figure 9] It is a perspective view showing the cam plate. [Figure 10] It is a perspective view showing the state in which the cam plate, the cam follower rod, the cam follower roller, and the shaft support part are combined. [Figure 11] It is an exploded cross-sectional view showing the structure of the cam follower roller at the end of the cam follower rod. [Figure 12] It is an explanatory view showing the problem when the shape of the cam follower roller is cylindrical. [Figure 13] It is an explanatory view showing that the problem described in FIG. 12 is solved when the shape of the cam follower roller is conical. [Figure 14] It is an explanatory view showing the external force acting in the case of the conical shape of the cam follower roller. [Figure 15] It is a flowchart showing the opening and closing control in the illustrated embodiment. [Figure 16] It is a block diagram of a control device for executing the control of FIG. 15. [Figure 17] It is an explanatory cross-sectional view showing the seal mechanism in the illustrated embodiment. [Figure 18] It is a perspective view of the hollow cylinder / flange composite member used in the seal mechanism of FIG. 1. [Figure 19] It is a perspective view of the C-ring used in the seal mechanism of FIG. 1.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the illustrated embodiment, the working fluid is, for example, high-pressure hydrogen gas. First, embodiments of the present invention will be described with reference to FIGS. 1 to 16. In Figure 1, which shows a cross-section of the flow control valve 100 according to the illustrated embodiment, the working fluid, high-pressure hydrogen gas, flows in from an inlet (not shown) (indicated by arrow A1), and is supplied downstream of the discharge port 2B via the flow path adjustment section 10 (arrow A2). In Figure 1, the flow path adjustment unit 10 has a valve body and a valve seat, and has the function of adjusting the flow rate by changing the valve opening. Details of the flow path adjustment unit 10 will be described later with reference to Figures 2 to 6.

[0016] In Figure 1, the flow control valve, which is shown as a whole by reference numeral 100, comprises a main body 2 (flow path adjustment casing), a shaft support 13 (valve stem support), a cam plate 11, a cam driven rod 12 (cam driven element), an electric motor 20 (drive source), and a reduction mechanism 21. A flow path 3 (see Figures 3 to 6) is formed in the main body 2, and the flow path 3 is part of the flow path adjustment section 10. The shaft support section 13 supports the shaft 1 (valve stem), and the shaft 1 is equipped with a shaft tip 1A (valve stem tip: see Figures 3 to 6). The electric motor 20 rotates the cam plate 11 via a reduction mechanism 21. A spring 15 is interposed between the contact portion 2E on the main body portion 2 and the contact portion 13E near the lower end of the shaft support portion 13, and the shaft support portion 13 is pressed downward by the spring 15 as shown in Figure 1. The flow control valve 100 has a cam plate side casing 14 and a shaft support casing 16. The cam plate side casing 14 surrounds the area from near the lower end of the shaft support 13 to below the cam driven rod 12 and the cam plate 11. The shaft support casing 16 surrounds the area from near the lower end of the main body 2 to near the lower end of the shaft support 13 and the spring 15.

[0017] The thickness of the cam plate (thickness in the vertical direction in Figure 1) changes smoothly in the radial and circumferential directions. The cam drive rod 12 is rod-shaped overall and has cam drive rollers 12A near both ends that are rotatably pressed against the surface 11A (upper surface: Figures 8 and 9) of the cam plate 11. The cam drive rollers 12A are rotatably pressed against the surface 11A of the cam plate 11 by the elastic force of the spring 15.

[0018] In Figure 1, elongated hole contact bearings 12B are provided at both ends of the cam driven rod 12, and are inserted into elongated holes 14A (see Figure 7) formed in the cam plate side casing 14, and are movable within the elongated holes 14A in the longitudinal direction (vertical direction in Figure 1). The bearing 12B for contact with the elongated hole is a bearing that can withstand radial loads.

[0019] In Figure 1, the cam drive rod 12 is mounted directly above the cam plate 11 and connected to the base 13A of the shaft support portion 13, which extends in the direction of the central axis C, via a connecting bearing 12C. The connecting bearing 12C is a bearing that receives thrust loads. The other end of the shaft support portion 13 (the end away from the cam drive rod 12: the upper end in Figure 1) is connected to the shaft 1.

[0020] In Figure 1, the reduction mechanism 21 is a mechanism that reduces and transmits the rotational speed of the output of the electric motor 20, which is the drive source. However, it is not limited to the structure shown, and conventionally known structures can be applied. However, in the illustrated embodiment, a reduction mechanism equipped with thrust bearings and the like that can withstand operation under conditions where high-pressure hydrogen gas is added is employed. Although not explicitly shown, thrust bearings can be attached to the gears of the reduction mechanism 21. The gear 21-1, which is located closest to the cam plate 11 among the gears constituting the reduction mechanism 21, and the cam plate 11 are integrated by fitting a key 17 into it. Although not shown in Figure 1, the illustrated embodiment includes a control unit CU (control device: see Figure 16) for controlling the flow rate of the flow control valve 100. It also has a measuring device 22 (rotation amount sensor: see Figure 16) for measuring the amount of rotation of the output shaft of the drive source (electric motor 20) or the amount of rotation of the gears constituting the reduction mechanism 21.

[0021] Next, the flow path adjustment unit 10 will be described with reference to Figures 2 to 6. In Figure 2, the characteristic relationship between the opening degree of the flow control valve and the hydrogen flow rate is shown by characteristic curve L1 (L11, L12). When the valve is opened from the closed state (origin in Figure 2), the flow rate gradually increases and moves to the upper region of Figure 2, transitioning from the low flow rate region R1 with a small opening degree to the high flow rate region R2 with an increased opening degree. In the low flow rate region R1, the slope θ1 of the characteristic curve L11 is small and the pressure rise is small, which minimizes damage to the fuel tank and various piping of the FCV (fuel cell vehicle) being refueled. On the other hand, in the high flow rate region R2, the slope θ2 of the characteristic curve L12 is large, resulting in a large hydrogen flow rate, which can meet the demand for high-speed hydrogen refueling. The operation of the flow control valve in the low flow rate region R1 will be explained with reference to Figures 3 to 5, and the operation of the flow control valve in the high flow rate region R2 will be explained with reference to Figure 6. In Figure 2, the symbol L13 indicates the boundary between the low flow rate region R1 and the second flow rate region R2. The state at boundary L13 will be explained with reference to Figure 5.

[0022] In Figure 3, a flow path 3 is formed in the flow path forming section 2C of the main body 2. The flow path 3 has a small-diameter section 3A that communicates with the outlet 2B, a large-diameter section 3B that communicates with the inlet 2A, and a tapered section 3AT that connects them. Arrow 2A indicates the direction of the inlet. A tapered shaft tip portion 1AT is formed on the inlet side (lower side in Figure 3) of the shaft tip 1A, and the tapered shaft tip portion 1AT is continuous with the shaft 1. In the state shown in Figure 3, the shaft tip 1A is inserted into the small-diameter flow path section 3A, and the tapered shaft tip section 1AT is in contact with the tapered flow path section 3AT, so the flow control valve 100 is closed. In Figure 3, a small radial annular gap δ exists between the outer surface of the shaft tip 1A and the inner surface of the small-diameter flow path 3A. When the flow control valve 100 is open, hydrogen flows through the annular gap δ at a small flow rate. The hydrogen flow rate in this case depends on the flow resistance in the annular gap δ, and this flow resistance is determined by the axial length of the shaft Lt (shaft tip insertion length) in which the shaft tip 1A is inserted into the small-diameter flow path 3A.

[0023] Figure 4 shows the state after moving shaft 1 to the lower side of Figure 3, compared to the state in Figure 3 where the valve is closed. In Figure 4, the tapered portion 1AT at the tip of the shaft is separated from the flow path tapered portion 3AT, and the flow control valve 100 is open. The shaft tip insertion length Lt is shorter compared to the state in Figure 3. In the state shown in Figure 4, the shaft tip insertion length Lt is relatively long, so the flow resistance in the annular gap δ is large, and the flow rate of hydrogen gas flowing through the gap δ is small. As shaft 1 descends further and the shaft tip insertion length Lt becomes shorter, the flow resistance in the gap δ decreases, and the hydrogen gas flow rate increases. In the flow control valve 100 according to the illustrated embodiment, the flow resistance is varied by changing the shaft tip insertion length Lt in which the shaft tip 1A is inserted into the small diameter flow path portion 3A, thereby allowing for fine adjustment of the flow rate of hydrogen gas flowing through the annular gap δ.

[0024] In the state shown in Figure 5, the end face 1AB of the shaft tip 1A aligns with the boundary 3C between the small-diameter flow path 3A and the tapered flow path 3AT. In Figure 5, the shaft tip insertion length Lt (see Figures 3 and 4) is zero. Figure 5 shows the state of the boundary L13 (Figure 2) between the small flow rate region R1 and the large flow rate region R2 in the illustrated flow control valve 100.

[0025] In Figure 6, which shows the state after further lowering of shaft 1 from the state in Figure 5, the end face 1AB of the shaft tip 1A is located below the boundary 3C between the small-diameter flow path 3A and the tapered flow path 3AT. The flow path through which hydrogen gas flows is composed of the region between the outer surface of the shaft tip 1A and the inner surface of the flow path tapered section 3AT. Its cross-sectional area is far larger than that of the annular gap δ, resulting in low flow resistance and a high hydrogen gas flow rate (high flow rate region R2). Furthermore, if shaft 1 descends further from the state shown in Figure 6, the cross-sectional area of ​​the hydrogen gas flow path increases dramatically. According to the illustrated flow control valve 100, the transition from the valve closed state to the low flow state to the high flow state is performed continuously and smoothly by moving the shaft tip 1A from the small diameter flow path section 3A towards the arrow 2A side (downward). Due to continuous operation, the hydrogen gas flow rate is low when the valve is opened immediately after closing, gradually increasing (low flow rate region R1), and then rapidly increasing from the state shown in Figure 5 (L13 in Figure 2) onward (high flow rate region R2). Here, the configuration of the flow path adjustment unit 10 shown in Figures 2 to 6 is merely illustrative. The flow path adjustment unit 10 in the illustrated embodiment can also be configured in the same way as, for example, the flow control valve shown in Patent Document 1.

[0026] In Figure 7, elongated holes 14A are formed on both sides of the cam plate side casing 14, and elongated hole contact bearings 12B, which are provided at the end of the cam driven rod 12 (Figure 8), are inserted into the elongated holes 14A. As a result, when the cam plate 11 (Figure 8) rotates due to the rotation of the motor 20 (drive source) transmitted via the reduction mechanism 21, the shaft support portion 13 and the shaft 1 do not rotate together around the central axis C, but move in the direction of the central axis C.

[0027] As shown in Figures 1 and 8, the shaft support portion 13 is connected to the cam driven rod 12 so as to surround it, and the shaft support portion 13 and the cam driven rod 12 are pressed toward the cam plate 11 by the spring 15. When the electric motor 20 rotates the cam plate 11, the inclination of the upper surface 11A of the cam plate 11 causes the cam drive rod 12 and the shaft support portion 13 to move in the direction of the central axis C of the shaft 1.

[0028] In Figure 8, when the cam plate 11 rotates, the inclination of the cam plate surface 11A causes the position of the cam plate surface 11A in the direction of the central axis C, where the two cam drive rollers 12A near both ends of the cam drive rod 12 are in contact, to change, causing the cam drive rod 12 to move in the direction of the central axis C. When the cam driven rod 12 moves in the direction of the central axis C, the shaft 1 (Figure 1) moves via the shaft support part 13 (Figure 1) connected to the cam driven rod 12, thereby adjusting the valve opening of the flow control valve 100. In other words, by controlling the rotation angle of the cam plate 11, the position of the cam driven rod 12 and the shaft 1 in the direction of the central axis C can be adjusted, and the valve opening degree of the flow control valve 100 can be controlled.

[0029] In the illustrated embodiment, the electric motor 20 is used as a power source, and the cam plate 11 and driven rod 12 convert rotational motion into linear motion, thereby allowing the valve body 1AT (Figures 3 to 6) to reciprocate in the axial direction C of the shaft 1 and adjust the valve opening. Furthermore, according to the illustrated embodiment, since a screw mechanism for converting rotational motion to linear motion is not employed, the pressure of the working fluid, high-pressure hydrogen gas, does not act on the threads of the screw mechanism, and no wear or damage occurs to the screw threads. As a result, the durability of the flow control valve 100 is improved. Furthermore, by appropriately arranging bearings on the driven rod 12, shaft support section 13, and reduction mechanism 21 to reduce resistance, the cam plate 11 can be rotated without using a large amount of power, and the position of the shaft 1 in the direction of the central axis C can be adjusted. Therefore, there is no need to provide large actuators or air valves as in conventional technology. By measuring the rotation amount of the electric motor 20 or the rotation amount of a predetermined point in the reduction mechanism 21, the positions of the cam plate surface 11A and the cam follower 12 can be identified, and by controlling the rotation amount, the position of the shaft 1 in the direction of the central axis C can be precisely controlled, making it possible to precisely control the flow rate of the high-pressure gas.

[0030] As shown in Figure 9, the cam surface 11A has inclined surfaces 11S (11S-1, 11S-2), flat surfaces 11F (11F-11, 11F-12, 11F-21, 11F-22), and a stepped portion 11ST, which correspond to the displacement of the amount of movement of the shaft 1 (Figure 1). The inclined surfaces 11S and flat surfaces 11F are formed so as to be point-symmetric with respect to the center of the opening 11B in the center of the cam plate 11. The flat surface 11F is provided to prevent inconvenience caused by the electric motor 20 (Figure 1) rotating too much, causing the cam plate 11 to rotate too much and the valve opening to be adjusted to deviate from a predetermined range. In other words, because of the flat surface 11F, even if the electric motor 20 and the cam plate 11 rotate too much, the shaft 1 will not be displaced more than necessary, preventing the valve opening from becoming larger or smaller than a predetermined amount, and ensuring that the opening and closing of the flow control valve 100 are performed within a predetermined range. This prevents damage to the valve seat 3AT and shaft 1.

[0031] The inclined surfaces 11S-1 and 11S-2, in the direction of movement SU of shaft 1, start at the same height as the flat surfaces 11F-11 and 11F-21, and gradually protrude in the direction of arrow SU relative to the flat surfaces 11F-11 and 11F-21 in the circumferential direction CL. After the inclined surfaces 11S-1 and 11S-2 have passed the position where they protrude the most in the direction of arrow SU, they reach the flat surfaces 11F-12 and 11F-22. The circumferential distance of the flat surfaces 11F-11 and 11F-21 is shorter than that of the inclined surfaces 11S-1 and 11S-2. Stepped sections 11ST are formed at the boundary between flat surface 11F-12 and flat surface 11F-21, and at the boundary between flat surface 11F-22 and flat surface 11F-11. In Figure 9, the height of the stepped section 11ST in the direction of arrow SU is indicated by the symbol H. The height dimension H of the stepped section 11ST is equal to the distance the central axis of the shaft moves when the valve at the shaft tip 1A is rapidly opened (Figure 3), or the distance from the position of the shaft tip 1A in Figure 3 (valve closed position of the flow control valve 100) to the position of the shaft tip 1A in Figure 6 (high flow region of the flow control valve 100).

[0032] Referring primarily to Figure 9, the normal opening and closing of the flow control valve 100 by the rotation of the cam plate 11 and the case of rapid opening will be explained. In normal valve opening and closing, the cam plate 11 rotates, while the cam driven rod 12 does not. However, the cam driven rollers 12A near both ends of the rod move relative to the cam plate 11 (relative rotation) while in contact with the inclined surfaces 11S-1 and 11S-2 of the cam plate 11, in a point-symmetrical manner with respect to the central opening 11B of the cam plate 11. In this process, the axial position of the shaft 1 is determined according to the amount that the inclined surface 11S protrudes toward the shaft 1 at the contact point between the cam-driven roller 12A and the inclined surface 11S (the amount that protrudes toward the arrow SU), and the valve opening of the flow control valve 100 is adjusted. For example, when the cam plate 11 moves in the direction of arrow CL, the amount of protrusion increases, and the shaft 1 moves in the direction that closes the flow control valve 100. On the other hand, when the cam plate 11 moves in the opposite direction of arrow CL, the amount of protrusion decreases, and the shaft 1 moves in the direction that opens the flow control valve 100. When the amount of protrusion increases and the contact position reaches a position adjacent to the flat surface 11F-12 or 11F-22, the flow control valve 100 is closed. On the other hand, when the amount of protrusion decreases and the contact position reaches a position adjacent to the flat surface 11F-11 or 11F-21, the flow control valve 100 is opened.

[0033] When the flow control valve 100 is in a closed state, and the cam plate 11 rotates in the direction of arrow CL, the contact position between the cam driven roller 12A and the inclined surface 11S moves beyond the stepped portion 11ST to the flat surface 11F-11 or 11F-21. At this time, the cam driven roller 12A descends by a height H in the direction of arrow SU on the stepped portion 11ST, and the shaft 1 moves in the direction that opens the flow control valve 100. As a result, the flow control valve 100 instantly opens completely from a closed state (rapid valve opening).

[0034] In Figure 10, which shows the assembled state of the cam plate 11, cam drive rod 12, cam drive roller 12A, and shaft support portion 13, the upper end of the valve stem support portion 13 is connected to the shaft 1 (valve stem). As shown in Figure 1, the lower end of the valve stem support portion 13 is connected to the cam drive rod 12 (cam drive element). The portion of the cam-driven roller 12A that contacts the cam plate surface 11A (upper surface) is formed in the shape of a truncated cone or a frustocone. In the cam-driven rod 12, a first thrust bearing 12D, a thrust bearing housing member 12E, a second thrust bearing 12F, and a fastening member 12G are provided radially outward from the cam-driven roller 12A. The second thrust bearing 12F and the thrust bearing housing member 12E constitute the elongated hole contact bearing 12B shown in Figures 1, 7, and 8.

[0035] As shown in Figure 11, an exploded cross-sectional view of the mounting structure of the cam-driven roller 12A, a bearing 12H that receives radial loads is arranged inside the cam-driven roller 12A. A bearing 12I that receives radial loads is arranged inside the thrust bearing housing member 12E. A first thrust bearing 12D is interposed radially inward of the thrust bearing housing member 12E (in the axial direction of the cam-driven rod 12, on the left side in Figure 11), and a second thrust bearing 12F is interposed radially outward (in the axial direction of the cam-driven rod 12, on the right side in Figure 11). As will be described later with reference to Figure 14, a force indicated by the symbol RA always acts radially outward on the frustoconical member of the cam-driven roller 12A. However, the first thrust bearing 12D supports the radially outward force RA, preventing the cam-driven roller 12A from shifting (moving) radially outward. In addition, the first thrust bearing 12D has the function of absorbing the rotational difference between the rotatable cam-driven roller 12A and the non-rotating thrust bearing housing member 12E. The two cam-driven rollers 12A positioned on the cam-driven rod 12 rotate in opposite directions to each other, causing twisting in the rod 12. The second thrust bearing 12F absorbs the twisting of the rod and has the function of preventing the fastening member 12G from loosening due to this twisting.

[0036] In contrast to the illustrated embodiment, the problems in the case where the shape of the cam-driven roller 12A is cylindrical (prior art) will be explained with reference to Figure 12. When the cam plate 11 rotates, the cylindrical member 12P rolls along the surface 11A of the cam plate in a circular trajectory as shown by trajectory α, acting as a cam-driven roller. At this time, the distance the cam-driven roller travels along the surface 11A of the cam plate varies depending on its distance from the rotation center of the cam plate 11. On the other hand, the distance traveled by the cylindrical member 12P in one rotation is constant, so slippage occurs at some point along dimension R of the cylindrical member 12P. To eliminate this, the ratio of the distance traveled by the cam-driven rod 12 to the distance traveled by the cam-driven roller 12A in one rotation must be equal, regardless of the distance from the rotation center of the cam plate 11.

[0037] In contrast, the illustrated embodiment employs a frustoconical member as the cam-driven roller 12A. If the virtual vertex VT of the frustoconical member 12A (the virtual vertex of the cone assuming the roller 12A is cone-shaped) coincides with the rotation center RC of the cam plate 11, and if the intersection of the extensions of the edges on both sides of the frustoconical shape coincides with the rotation center RC of the cam plate 11, then the ratio of the travel distance of the cam driven rod 12 to the travel distance of the cam driven roller 12A when it rotates once becomes equal, and slippage is prevented. In the illustrated embodiment, the virtual vertex VT of the frustoconical roller 12A coincides with the rotation center RC of the cam plate 11.

[0038] In Figure 14, which shows the frustoconical member 12A on the cam plate surface 11A viewed from the side, a downward pressing force F1 is constantly acting on the frustoconical member 12A, which is a cam-driven roller, due to the high pressure of the working gas. Therefore, a radially outward force RA is constantly acting on the frustoconical member 12A. A first thrust bearing 12D, shown in Figures 10 and 11, is provided to support the radially outward force RA acting on the frustoconical member 12A.

[0039] The opening and closing control of the flow control valve 100 described above will be explained primarily with reference to Figure 15. In Figure 15, in step S1, the rotational speed of the electric motor 20 (Figure 1) is measured by the rotational speed measuring device 22 (see Figure 16). When measuring the rotational speed, instead of measuring the electric motor 20, the rotational speed of any gear in the reduction mechanism 21 (Figure 1) may be measured. In step S2, the valve opening degree of the flow control valve 100 is calculated and determined based on the amount of rotation (of either the electric motor 20 or the gear of the reduction mechanism 21) measured in step S1. In calculating the valve opening of the flow control valve 100, the amount of movement in the direction of the central axis C of the shaft 1 is calculated based on the amount of rotation measured in step S1, and the valve opening of the flow control valve 100 is calculated. Here, various parameters may be determined by calculation, but it is also possible to specify formulas or diagrams that show the relationships between them in advance and determine the necessary parameters from those formulas or diagrams.

[0040] In the following step S3, the valve opening of the flow control valve 100 calculated and determined in step S2 is compared with a target value (valve opening in Figure 2). The target value of the valve opening is, for example, a target value with elapsed time as a parameter, and is, for example, the characteristic shown in Figure 2, but it may also be determined by parameters other than elapsed time. In step S4, based on the comparison results from step S3, it is determined whether the valve opening of the flow control valve 100 determined in step S2 is within a predetermined range of the target value. If the result of the determination in step S4 indicates that the valve opening of the flow control valve 100 is smaller than the predetermined range of the target value, the process proceeds to step S5. If the valve opening is larger than the predetermined range of the target value, the process proceeds to step S6. If the valve opening of the flow control valve 100 is within the predetermined range of the target value (step S4 is "Yes"), the process proceeds to step S7 without rotating the electric motor 20.

[0041] In step S5 (when the valve opening is smaller than a predetermined range of the target value), the electric motor 20 is rotated by a predetermined small amount in the direction of increasing the valve opening of the flow control valve 100. In step S6 (when the valve opening is greater than a predetermined range of the target value), the electric motor 20 is rotated by a predetermined small amount in the direction of decreasing the valve opening of the flow control valve 100. In step S7 (if the valve opening is within a predetermined range of the target value), it is determined whether or not the hydrogen gas filling using the system including the flow control valve 100 has been completed. If step S7 determines that "filling is complete" (step S7 is "Yes"), the hydrogen gas filling operation is terminated. If it is not "filling complete" (step S7 is "No"), the process returns to step S1 (a loop of step S7 being "No"). Although not shown in Figure 15, in the case of rapid valve opening, it is determined whether the flow control valve 100 is in a closed state and whether rapid opening should be performed according to the hydrogen filling protocol. If rapid opening should be performed, the electric motor 20 is rotated to move the contact position between the cam driven roller 12A and the inclined surface 11S of the cam plate 11 from the flat surfaces 11F-12 and 11F-22, over the stepped portion 11ST, to the flat surfaces 11F-21 and 11F-11.

[0042] The control unit CU, which controls the opening and closing of the flow control valve 100 as explained with reference to Figure 15, will now be explained with reference to Figure 16. In Figure 16, the control unit CU includes a valve opening determination block B1, a comparison block B2, a control signal output block B3, and a memory block B4. The valve opening determination block B1 acquires the detected rotation amount from the electric motor rotation amount detection sensor 22 (measuring device), which measures the rotation amount of the electric motor 20, via the signal transmission line SL1. As described above, instead of measuring the rotation amount of the electric motor 20, the rotation amount of any gear in the reduction mechanism 21 may be measured. The valve opening determination block B1 acquires the "rotation amount of the electric motor 20 - valve opening of the flow control valve 100" stored in the memory block B4 via the signal transmission line SL2. The relationship between the rotation amount of the electric motor 20 and the amount of central axis protrusion at the contact point between the cam plate inclined surface 11S and the cam driven roller 12A (the amount of movement in the direction of the central axis C of the shaft 1 and the shaft tip 1A) or the valve opening degree of the flow control valve 100 can be predetermined, and the valve opening degree of the flow control valve can be calculated from the rotation amount of the electric motor 20, etc., based on this predetermined relationship.

[0043] The valve opening determination block B1 has the function of calculating and determining the valve opening of the flow control valve 100 by comparing the detected rotational amount of the electric motor 20, etc., with the "rotational amount of the electric motor 20 - valve opening characteristics of the flow control valve 100". The "valve opening of the flow control valve 100" determined in valve opening determination block B1 is transmitted to comparison block B2 via signal transmission line SL3.

[0044] Comparison block B2 obtains the target value of the valve opening of the flow control valve 100 (for example, a target value with elapsed time as a parameter) from memory block B4 via signal transmission line SL4. The comparison block B2 has the function of comparing the valve opening of the flow control valve 100 determined by the valve opening determination block B1 with the target value of the valve opening. The comparison result from comparison block B2 is transmitted to control signal output block B3 via signal transmission line SL5.

[0045] The control signal output block B3 has the function of outputting a control signal to the electric motor 20 via the signal transmission line SL6 so that the valve opening of the flow control valve 100 becomes a target value (or a value within a predetermined range from the target value) based on the comparison result by the comparison block B2. As explained in steps S5 and S6 of Figure 15, the control signal is either a "control signal to rotate the electric motor 20 in a direction that increases the valve opening of the flow control valve 100" or a "control signal to rotate the electric motor 20 in a direction that decreases the valve opening of the flow control valve 100". Memory block B4 has the function of storing information and data necessary for the opening and closing control of the flow control valve 100 and providing it to each functional block as needed. The information and data stored in memory block B4 include, for example, specification data for the components that make up the flow control valve 100 (shaft 1, main body 2, flow path 3, cam plate 11, inclined surface 11S of the cam plate 11, cam driven rod 12, electric motor 20, reduction mechanism 21), the rotation amount of the electric motor 20 - valve opening degree of the flow control valve 100 characteristics, and target values ​​for the valve opening degree of the flow control valve 100.

[0046] Next, the sealing mechanism will be described with reference to Figures 17, 18, and 19. To prevent high-pressure hydrogen from leaking from the sliding part of the shaft 1 (valve stem), a sealing mechanism 30 is provided in the flow control valve 100 at the position where the shaft 1 slides on the valve stem support part 13. To avoid complexity in the illustration, the sealing mechanism 30 is not shown in Figure 1.

[0047] In Figure 18, the hollow cylinder-flange composite member 33 has a hollow cylindrical region 33A (main body) that extends in the central axis direction (vertical direction), and the hollow cylinder-flange composite member 33 is inserted into the hollow portion 32A (Figure 17) at the radial center of the C-ring 32. This prevents the C-ring 32 from contracting radially inward. 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 (Figure 17) are placed on the flange 33B. The backup ring 34 is provided above the O-ring 35, and the O-ring 35 is sandwiched between the two backup rings 34, 34. The sealing mechanism 30 shown in Figure 17 is constructed by stacking multiple units C32-35, each consisting of an O-ring 35, two backup rings 34, 34, a hollow cylindrical / flange composite member 33, and a C-ring 32. Figure 17 shows a state where two units C32-35 are stacked.

[0048] By adopting this configuration, the enlarged diameter portion 31A into which the C-ring 32 fits can be formed without increasing the inner diameter of the hollow portion in which the valve stem operating shaft 13 slides. This allows for easy arrangement of the sealing mechanism 30, which is constructed by stacking multiple stages of units C32-35, and reliably prevents leakage of high-pressure hydrogen gas. Furthermore, the sealing mechanism 30 can be positioned at any position where the shaft slides, not just at the sliding position of the valve stem operating shaft 13. 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 open side is facing upwards (towards the discharge port 2B in Figure 1).

[0049] The C-ring 32 shown in Figure 19 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 cylindrical 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 Figure 1) 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.

[0050] The backup ring 34, which is not shown as a separate item, is made of resin and prevents the O-ring 35 from rupturing at the point where a portion of the O-ring 35 extends under high pressure and enters the gap with the inner wall (so-called "O-ring overhang").

[0051] The illustrated embodiments are for illustrative purposes only and are not intended to limit the technical scope of the present invention. [Explanation of Symbols]

[0052] 1. Shaft (valve stem) 1A... Small diameter tip 2. Main body 3...flow channel 3A... Small diameter section of the flow path 3B...Large diameter channel section 11. Cam plate 11A... Cam surface (top surface of cam plate) 12. Cam-driven rod (cam-driven element) 12A... Cam-driven roller 13...Valve stem support part 20. Electric motor (power source) 21...Reduction mechanism 22. Measuring devices 100... Flow control valve C... the central axis of the shaft CU... Control Unit (Control Device) Lt... Dimensions of the shaft being inserted into the flow path RC... Center of rotation of the cam plate δ···Gap between the outer circumference of the shaft tip and the inner surface of the small diameter section of the flow path

Claims

1. A cam plate with a slope formed on its surface, A drive source that rotates the cam plate via a reduction mechanism, A cam follower having a rotating part that is pressed against the surface of the cam plate, and which moves in the direction of the central axis of the flow control valve due to the inclination of the surface of the cam plate, It has a valve stem support portion, one end of which is connected to a cam follower and the other end of which is connected to a valve stem. The cross-sectional area of ​​the flow path and the flow rate vary depending on the dimensions to which the valve stem is inserted into the flow path. The cam follower is configured as a rod, and cam follower rollers are provided near both ends that are rotatably pressed against the surface of the cam plate. A flow control valve characterized in that the thickness dimension of the cam plate is small in the radially outward direction and large in the radially inward direction, the surface of the cam plate on which the cam follower rolls is inclined, the portion of the cam follower roller that contacts the cam plate is configured as a frustoconical shape, and the inclined surface of the cam plate is complementary in shape to the frustoconical portion of the cam follower roller.

2. The flow control valve according to claim 1, wherein the frustoconical portion of the cam-driven roller is set such that the point where the extensions of the edges of the frustoconical shape intersect becomes the rotation center of the cam plate.

Images