Double eccentric valve

Abstract

A flow path (11) of a double eccentric valve is provided with a press-fit portion (10) for a valve seat (13). The press-fit portion (10) includes: a first contact surface (31) which intersects with the direction of press-fitting (DP) into the press-fit portion (10) of the valve seat (13) and with which the valve seat (13) comes in contact; and a second contact surface (32). The first contact surface (31) and the second contact surface (32) are adjacent to each other so as to be separated by a level difference in the direction of press-fitting (DP). The valve seat (13) includes a valve seat base portion (21) made of a rigid material, and a sealing member (22) is provided inside the valve seat base portion (21). The valve seat base portion (21) has, at an end thereof in the direction of press-fitting (DP), a contact portion (21a) that contacts the first contact surface (31). The sealing member (22) has, at an end thereof in the direction of press-fitting (DP), a protrusion (22a) that contacts the second contact surface (32). The protrusion (22a) contacts the second contact surface (32) at a position that is separated from the contact portion (21a) of the valve seat base portion (21) in the direction of press-fitting (DP).

Description

Double eccentric valve

[0001] The technology disclosed in this specification relates to, for example, a double eccentric valve used in a flow path of a fuel cell system.

[0002] Conventionally, as this type of technology, for example, the technology "double eccentric valve" described in Patent Document 1 below is known. This double eccentric valve includes a housing including a flow path, a valve seat provided in the flow path, a valve body provided corresponding to the valve seat, a sealing member provided on the valve seat and interposed between the valve body and the valve seat when the valve body seats on the valve seat to seal between the valve body and the valve seat, and a rotating shaft for rotating the valve body. The valve seat and the sealing member are in contact with the same plane (contact surface) formed in the press-fitting portion in a state of being press-fitted into the press-fitting portion of the flow path.

[0003] Japanese Patent Application Laid-Open No. 2022-52262

[0004] By the way, in the double eccentric valve described in Patent Document 1, in order to prevent leakage between the press-fitting portion and the valve seat, the end portion of the sealing member in the press-fitting direction of the valve seat is pressed against the contact surface of the press-fitting portion, and by ensuring a "crushing allowance" by this pressing, the sealing performance by the sealing member is ensured. Therefore, in order to press-fit the valve seat into the press-fitting portion and ensure the sealing performance by the sealing member, a press-fitting load exceeding the reaction force of the sealing member is required. Therefore, it has not been easy to assemble the valve seat into the press-fitting portion while ensuring the sealing performance by the sealing member.

[0005] This disclosed technology has been made in view of the above circumstances, and its object is to facilitate the assembly of a double eccentric valve into a press-fitting portion of a valve seat while ensuring the sealing performance by a sealing member.

[0006] (1) To achieve the above objective, one aspect of the present disclosure provides a double eccentric valve comprising: a housing including a fluid passage; a valve seat provided in the passage and having a valve hole; a valve body having a sealing surface formed on its outer circumference and provided corresponding to the valve seat; the valve seat including a sealing member made of an elastic material that contacts the sealing surface of the valve body to seal the space between the valve body and the valve seat when the valve body is seated on the valve seat in a fully closed position; and a rotating shaft for rotating the valve body, the axis of the rotating shaft which is the rotation center of the valve body being positioned away from the sealing surface of the valve body in the direction in which the axis of the valve body extends, and away from the axis of the valve body in the radial direction of the valve body. In the valve, the flow path is provided with a press-fit section into which a valve seat is press-fitted. The press-fit section intersects with the press-fitting direction of the valve seat into the press-fit section and includes a first contact surface and a second contact surface into which the valve seat abuts. The first and second contact surfaces are adjacent to each other, separated by a step in the press-fitting direction. The valve seat includes a valve seat base made of a rigid material, and a sealing member is provided inside the valve seat base. The valve seat base has a contact portion at its end in the press-fitting direction into the press-fit section that abuts against the first contact surface. The sealing member has a protrusion at its end in the press-fitting direction into the press-fitting section that abuts against the second contact surface. The protrusion is intended to abut the second contact portion at a position further in the press-fitting direction than the contact portion of the valve seat base.

[0007] In this embodiment, by press-fitting the valve seat into the press-fit portion of the flow path, the contact portion of the valve seat base, made of a rigid material, contacts the first contact surface of the press-fit portion, and the protrusions of the sealing member, made of an elastic material, contact the second contact surface. In this press-fit state, the contact portion of the valve seat base contacts the first contact surface, restricting the press-fitting direction of the valve seat. Furthermore, the protrusions of the sealing member contact the second contact surface and are crushed, sealing the space between the valve seat and the press-fit portion. Therefore, to ensure the sealing performance by the sealing member, only the protrusions need to be crushed, reducing the reaction force of the sealing member and reducing the press-fitting load of the valve seat into the press-fit portion.

[0008] The technology described in (2) is intended to be used in the manner of (1) for adjusting the air flow rate in a fuel cell system.

[0009] According to this embodiment, a double eccentric valve used for adjusting the air flow rate in a fuel cell system can be made to perform the same function as the technology described in (1) above.

[0010] (1) According to the technology described above, the sealing performance of the double eccentric valve can be ensured by the sealing member, and the assembly of the valve seat to the press-fit portion can be facilitated.

[0011] According to the technology described in (2), the same effect as the technology described in (1) can be obtained as a double eccentric valve used for adjusting the air flow rate in a fuel cell system.

[0012] A schematic diagram showing a fuel cell system in which a double eccentric valve is used according to one embodiment. A perspective view showing a double eccentric valve according to one embodiment. A perspective view showing a double eccentric valve in a partially cutaway state in a fully closed state according to one embodiment. A perspective view showing a double eccentric valve in a partially cutaway state in a fully open state according to one embodiment. A side view showing the valve seat, valve body, and rotating shaft of a double eccentric valve in a fully closed state according to one embodiment. A cross-sectional view of the double eccentric valve along line A-A in Figure 5 according to one embodiment. A cross-sectional view showing the area around the valve seat and press-fit section according to one embodiment. An enlarged view showing the valve seat and press-fit section, specifically the area enclosed by the dashed-dotted circle in Figure 7, according to one embodiment. A cross-sectional view showing the state immediately before the valve seat is press-fitted into the press-fit section according to one embodiment.

[0013] Hereinafter, one embodiment of the double eccentric valve, used as a fluid flow path in a fuel cell system, will be described in detail with reference to the drawings.

[0014] [About the Fuel Cell System] A fuel cell system using a double eccentric valve will be described. Figure 1 shows a schematic configuration of the fuel cell system 101 of this embodiment. As shown in Figure 1, the fuel cell system 101 has a fuel cell (hereinafter referred to as "FC stack") 111, a hydrogen system 112, and an air system 113.

[0015] The FC stack 111 generates electricity by receiving a supply of fuel gas (hydrogen gas) and an oxidizer gas (air). Specifically, the FC stack 111 generates electricity by receiving hydrogen gas from the hydrogen system 112 and air from the air system 113. The electricity generated by the FC stack 111 is supplied to a drive motor (not shown) via, for example, an inverter (not shown).

[0016] The hydrogen system 112 includes a hydrogen supply passage 121 and a hydrogen discharge passage 122. The hydrogen supply passage 121 is a passage for supplying hydrogen gas from a hydrogen tank (not shown) to the FC stack 111. The hydrogen discharge passage 122 is a passage for discharging hydrogen gas (hydrogen off-gas) discharged from the FC stack 111.

[0017] The air system 113 includes an air supply passage 131, an air discharge passage 132, and a bypass passage 133. The air supply passage 131 is a passage for supplying air to the FC stack 111 from outside the fuel cell system 101. The air discharge passage 132 is a passage for discharging air (air-off gas) discharged from the FC stack 111. The bypass passage 133 is a passage for allowing air to flow from the air supply passage 131 to the air discharge passage 132 without passing through the FC stack 111.

[0018] The air system 113 includes an inlet sealing valve 141 in the air supply passage 131. The inlet sealing valve 141 is a valve that opens and closes the air supply passage 131 and switches between supplying and shutting off air to the FC stack 111. In this embodiment, a double eccentric valve 1, which will be described later, is used as the inlet sealing valve 141.

[0019] Furthermore, the air system 113 includes an outlet sealing valve 142 in the air discharge passage 132. The outlet sealing valve 142 is a valve that opens and closes the air discharge passage 132 and switches between discharging and shutting off the air-off gas from the FC stack 111. In this embodiment, a double eccentric valve 1, which will be described later, is used as the outlet sealing valve 142.

[0020] Furthermore, the air system 113 includes a bypass valve 143 in the bypass passage 133. The bypass valve 143 is a valve that controls the flow rate of air in the bypass passage 133. Note that a double eccentric valve 1, which will be described later, may be used as the bypass valve 143.

[0021] In the fuel cell system 101 described above, hydrogen gas supplied to the FC stack 111 from the hydrogen supply passage 121 is used for power generation in the FC stack 111. Hydrogen gas not used for power generation is discharged to the outside as hydrogen off-gas from the FC stack 111 via the hydrogen discharge passage 122. In addition, air supplied to the FC stack 111 from the air supply passage 131 is used for power generation in the FC stack 111. Air not used for power generation is discharged to the outside as air off-gas from the FC stack 111 via the air discharge passage 132.

[0022] [Regarding the double eccentric valve] Next, we will describe the double eccentric valve used as the inlet sealing valve 141, outlet sealing valve 142, and bypass valve 143 in the FC stack 111 described above.

[0023] Figure 2 shows a perspective view of the double eccentric valve 1 of this embodiment. As shown in Figure 2, the double eccentric valve 1 comprises a valve section 2, a motor section 3 containing a motor, and a reduction gear section 4 containing a plurality of gears. The valve section 2 includes a pipe section 12 having a flow path 11. A valve seat 13, a valve body 14, and a rotating shaft 15 are arranged in the flow path 11. The rotational force of the motor is transmitted to the rotating shaft 15 via a plurality of gears. In this embodiment, the pipe section 12 constitutes part of the housing 6. The motor of the motor section 3 and the plurality of gears of the reduction gear section 4 are covered by this housing 6. The housing 6 is made of a metal such as aluminum.

[0024] Figure 3 shows a perspective view of the double eccentric valve 1 with the valve section 2 in the fully closed state partially cut away. Figure 4 shows a perspective view of the double eccentric valve 1 with the valve section 2 in the fully open state partially cut away. As shown in Figures 3 and 4, a stepped press-fit section 10 is formed in the pipe section 12. In this embodiment, the valve seat 13 is assembled by press-fitting it into this press-fit section 10.

[0025] The valve seat 13 is annular in shape and has a circular or substantially circular valve bore 16 in the center. An annular seat surface 17 is formed on the edge of the valve bore 16. In this embodiment, the valve seat 13 includes a sealing member 22 for sealing the space between the valve seat 13 and the valve body 14. The seat surface 17 is formed on the sealing member 22. Details of the valve seat 13 will be described later.

[0026] The valve body 14 is disc-shaped, and an annular sealing surface 18 corresponding to the seat surface 17 is formed on its outer circumference. The valve body 14 is fixed to the rotating shaft 15 and rotates integrally with the rotating shaft 15, contacting and separating from the valve seat 13.

[0027] Figure 5 shows a side view of the double eccentric valve 1, including the valve seat 13, valve body 14, and rotating shaft 15 in the fully closed state. Figure 6 shows the double eccentric valve 1 in a cross-sectional view along line A-A in Figure 5. As shown in Figure 6, the axis L1 of the rotating shaft 15 extends parallel to the radial direction of the valve body 14 and valve bore 16, and is positioned eccentrically from the center P1 of the valve bore 16 in the radial direction of the valve bore 16. In conjunction with this, the sealing surface 18 of the valve body 14 is positioned eccentrically in the direction in which the axis L2 of the valve body 14 extends from the axis L1 of the rotating shaft 15.

[0028] As shown in Figures 5 and 6, the valve body 14 includes a fixing portion 14b that protrudes from its upper plate surface 14a and is fixed to the rotating shaft 15. The rotating shaft 15 has a pin 15a that protrudes from the tip of the rotating shaft 15 at a position offset radially from its axis L1. The fixing portion 14b is fixed to the rotating shaft 15 via the pin 15a. Also, as shown in Figure 6, the fixing portion 14b is positioned on the axis L2 of the valve body 14, and the valve body 14 including the fixing portion 14b has a symmetrical shape with respect to the axis L2 of the valve body 14.

[0029] In this configuration, the double eccentric valve 1 is displaced from a fully closed state (see Figure 3) where the sealing surface 18 of the valve body 14 abuts against the seat surface 17 of the valve seat 13, to a fully open state (see Figure 4) where the sealing surface 18 of the valve body 14 is separated from the seat surface 17 of the valve seat 13, by rotating the valve body 14 around the axis L1 of the rotation shaft 15.

[0030] [Regarding the structure of the valve seat and press-fit section] Figure 7 shows a cross-sectional view (a cross-sectional view of the valve seat 13 cut along its axial direction) of the area around the valve seat 13 and the press-fit section 10. Figure 8 shows an enlarged view of the area S1 enclosed by the dashed-dotted circle in Figure 7. Figure 9 shows a cross-sectional view (a cross-sectional view of the valve seat 13 cut along its axial direction) of the state immediately before the valve seat 13 is press-fitted into the press-fit section 10. In Figures 7 and 9, the valve body 14 and the rotating shaft 15 are omitted for the sake of explanation.

[0031] As shown in Figures 7 to 9, the valve seat 13 includes a valve seat base 21 made of a rigid material and a sealing member 22 made of an elastic material that is provided inside the valve seat base 21. Both the valve seat base 21 and the sealing member 22 are formed in an annular shape (more specifically, an annular or substantially annular shape). The valve seat base 21 is formed of a metal plate such as stainless steel and has a channel-shaped radial cross-section. The sealing member 22 is formed of rubber in a substantially cylindrical shape. The sealing member 22 is integrally attached to the valve seat base 21 by means of baking or other methods.

[0032] The press-fit portion 10 is formed in a stepped shape on the lower inner wall of the flow path 11. The press-fit portion 10 comprises a first contact surface 31, a second contact surface 32, and a press-fit surface 33. The first contact surface 31 and the second contact surface 32 are formed so as to intersect (perpendicular to) the press-fit direction DP of the valve seat 13 into the press-fit portion 10. The first contact surface 31 and the second contact surface 32 are formed adjacent to each other in the radial direction, separated by a step in the press-fit direction DP. The first contact surface 31 and the second contact surface 32 form an annular shape in plan view. The first contact surface 31 is the surface to which one end (lower side) of the valve seat base 21 in the axial direction (up and down direction in Figures 7 and 8) abuts. The second contact surface 32 is the surface to which one end (lower side) of the seal member 22 in the axial direction (up and down direction in Figures 7 and 8) abuts. The second contact surface 32 is positioned at a location offset from the first contact surface 31 in the press-fit direction DP (downward in Figure 8).

[0033] The valve seat base 21 has a flat contact portion 21a at its end in the press-fitting direction DP that contacts the first contact surface 31.

[0034] The sealing member 22 has a protrusion 22a at its end in the press-fitting direction DP that contacts the second contact surface 32. This protrusion 22a is formed continuously in an annular shape in the circumferential direction of the sealing member 22. The tip of this protrusion 22a is positioned further in the press-fitting direction DP than the contact portion 21a of the valve seat base 21. As shown in Figure 8, this protrusion 22a contacts the second contact surface 32, and at least a part of it is crushed by the pressure, sealing the space between the valve seat 13 and the press-fit portion 10. Note that, as shown in Figure 9, when the protrusion 22a is not in contact with the second contact surface 32, it is not crushed and protrudes in the press-fitting direction DP. That is, the protrusion 22a contacts the second contact surface 32 at a position further in the press-fitting direction DP than the contact portion 21a of the valve seat base 21.

[0035] The seat surface 17 of the sealing member 22 is formed at the end of the sealing member 22 opposite to the side of the second contact surface 32 (upper side) in the axial direction (up and down direction in Figures 7 and 8). When the double eccentric valve 1 is in the fully closed state (see Figure 3), the seat surface 17 contacts the sealing surface 18 of the valve body 14, sealing the space between the valve seat 13 and the valve body 14.

[0036] Furthermore, as shown in Figure 8, the press-fit portion 10 is formed with a press-fit guide portion 34 that guides the valve seat base 21 to the press-fit surface 33 when the valve seat 13 is pressed into the press-fit surface 33 in the press-fit direction DP.

[0037] [Operation and Effects of the Double Eccentric Valve] According to the configuration of the double eccentric valve 1 of this embodiment described above, by press-fitting the valve seat 13 into the press-fit portion 10 of the flow path 11, the contact portion 21a of the stainless steel valve seat base 21 comes into contact with the first contact surface 31 of the press-fit portion 10, and the protrusion 22a of the rubber sealing member 22 comes into contact with the second contact surface 32. In this press-fit state, the contact portion 21a of the valve seat base 21 comes into contact with the first contact surface 31, restricting the press-fitting of the valve seat 13 in the press-fitting direction DP. In other words, the contact portion 21a of the valve seat base 21 can function as a stopper that restricts the press-fitting of the valve seat 13 into the press-fit portion 10. In addition, the protrusion 22a of the sealing member 22 comes into contact with the second contact surface 32 and is crushed, sealing the space between the valve seat 13 and the press-fit portion 10. Therefore, in order to ensure the sealing performance of the sealing member 22, only the protrusion 22a needs to be crushed, reducing the reaction force of the sealing member 22 and the press-fitting load of the valve seat 13 into the press-fitting portion 10. As a result, the sealing performance of the double eccentric valve 1 can be ensured by the sealing member 22, and the assembly of the valve seat 13 into the press-fitting portion 10 can be made easier.

[0038] According to the configuration of this embodiment, the valve seat base 21 is formed from a metal plate such as stainless steel, and its radial cross-section is channel-shaped. Therefore, the weight of the valve seat base 21 can be reduced, and consequently, the weight of the valve seat 13 can be reduced.

[0039] According to the configuration of this embodiment, the double eccentric valve 1 described above is used in the FC stack 111 shown in Figure 1 as an inlet sealing valve 141, an outlet sealing valve 142, and a bypass valve 143 for adjusting the air flow rate. Therefore, the same operation and effects as described above can be obtained when using the double eccentric valve 1 in the fuel cell system 101.

[0040] Furthermore, this disclosed technology is not limited to the embodiments described above, and it can be implemented by appropriately modifying a part of the configuration without departing from the spirit of the disclosed technology.

[0041] In the above embodiment, the double eccentric valve 1 was implemented in various valves 141 to 143 used in the airflow path of the fuel cell system 101, but the implementation of the double eccentric valve is not limited to a fuel cell system.

[0042] 1 Double eccentric valve 6 Housing 10 Press-fit section 11 Flow path 13 Valve seat 14 Valve body 15 Rotating shaft 16 Valve hole 21 Valve seat base 21a Contact section 22 Seal member 22a Ridge 31 First contact surface 32 Second contact surface 101 Fuel cell system 141 Inlet sealing valve 142 Outlet sealing valve 143 Bypass valve DP Press-fit direction L1 Axis (of the rotating shaft) L2 Axis (of the valve body)

Claims

1. A double eccentric valve comprising: a housing including a fluid passage; a valve seat provided in the fluid passage and having a valve hole; a valve body having a sealing surface formed on its outer circumference and provided corresponding to the valve seat; the valve seat including a sealing member made of an elastic material for sealing the space between the valve body and the valve seat by contacting the sealing surface of the valve body when the valve body is seated on the valve seat in a fully closed position; a rotating shaft for rotating the valve body; the axis of the rotating shaft, which is the rotation center of the valve body, is positioned away from the sealing surface of the valve body in the direction in which the axis of the valve body extends, and is positioned away from the axis of the valve body in the radial direction of the valve body; wherein the fluid passage is provided with a press-fit portion into which the valve seat is press-fitted; the press-fit portion includes a first contact surface and a second contact surface that intersect with the press-fitting direction of the valve seat into the press-fitting portion and into which the valve seat abuts; the first contact surface and the second contact surface are adjacent to each other with respect to a step in the press-fitting direction; The valve seat includes a valve seat base made of a rigid material, the sealing member is provided inside the valve seat base, the valve seat base has a contact portion at its end in the direction of press-fitting into the press-fit portion that contacts the first contact surface, and the sealing member has a protrusion at its end in the direction of press-fitting into the press-fit portion that contacts the second contact surface, the protrusion contacts the second contact surface at a position further away in the press-fitting direction than the contact portion of the valve seat base, characterized in that it is a double eccentric valve.

2. A double eccentric valve according to claim 1, characterized in that it is used for adjusting the flow rate of air in a fuel cell system.

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