Relief valve

Abstract

To provide a relief valve for suppressing the occurrence of a liquid reservoir phenomenon when a housing is installed on a mounted member in a horizontal state, while downsizing the relief valve.SOLUTION: A relief valve 15 includes: a cylindrical housing 20 mounted on a mounted member 10 having a relief hole 10a for fluid; a valve seat 24 provided at one end of the housing 20; and a valve element 30 provided in the housing 20 movably in an axial direction so as to be normally seated on the valve seat 24 and removed from the valve seat 24 when the pressure of fluid exceeds a predetermined value. The valve seat 24 is protruded radially inward from an opening part on one end side of the housing 20, and is formed in an annular shape having a hollow part as an introduction port 25 for fluid. At least one end of the housing 20 is inserted into the relief hole 10a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to a relief valve.

Background Art

[0002] Conventionally, for example, there is a relief valve described in Patent Document 1. The cylindrical body of the relief valve has a cylindrical portion that communicates with the inlet of the valve seat at its tip and extends in the axial direction. The tip-side half of the body is screwed into the relief hole of the member to be attached. Note that the body corresponds to the "housing" referred to in this specification.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the conventional example, since the body has a cylindrical portion, the axial length of the body becomes long, leading to an increase in the size of the relief valve. Also, for example, when the body is installed horizontally on the member to be attached, a liquid accumulation phenomenon may occur where a part of the fluid (gas, liquid, etc.) accumulates in the cylindrical portion.

[0005] The problem to be solved by the technology disclosed in this specification is to suppress the occurrence of the liquid accumulation phenomenon when the housing is installed horizontally on the member to be attached while miniaturizing the relief valve.

Means for Solving the Problems

[0006] To solve the above problems, the technology disclosed in this specification takes the following means.

[0007] The first means is a relief valve comprising a cylindrical housing attached to an attachment member having a fluid relief hole, a valve seat provided at one end of the housing, and a valve body movably provided axially within the housing, which normally seats on the valve seat and disengages from the valve seat by a pressure exceeding a predetermined value of the fluid. The valve seat is formed in an annular shape that projects radially inward at an opening on one end side of the housing and has a hollow portion as an inlet for the fluid. At least one end of the housing is configured to be inserted into the relief hole.

[0008] According to the first means, the valve seat of the housing is formed in an annular shape that projects radially inward at an opening on one end side of the housing and has a hollow portion as an inlet for the fluid. Therefore, by omitting the cylindrical portion of the body according to the conventional example and shortening the axial length of the housing, the relief valve can be miniaturized. Further, by inserting at least one end of the housing into the relief hole of the attachment member, the amount of protrusion of the housing from the attachment member can be reduced. Further, by omitting the cylindrical portion of the body according to the conventional example, the occurrence of a liquid pooling phenomenon when the housing is installed horizontally on the attachment member can be suppressed.

[0009] The second means is the relief valve of the first means, wherein the wall surface of the inlet is a tapered surface whose inner diameter gradually decreases from the inlet side to the outlet side.

[0010] According to the second means, when the housing is installed horizontally on the attachment member, the occurrence of a liquid pooling phenomenon occurring at the inlet can be suppressed.

[0011] The third means is the relief valve of the first or second means. An annular contact portion that can be seated on the valve seat is formed on the valve body. A disc-shaped seal member that elastically seals between the valve body and the valve seat is provided within the contact portion. The outer peripheral surface of the protruding portion that protrudes from the contact portion of the valve body in the free state of the seal member is a tapered surface whose outer diameter gradually increases from the tip side toward the base side. It is a relief valve.

[0012] According to the third means, the outer peripheral surface of the protruding portion that protrudes from the contact portion of the valve body in the free state of the seal member is a tapered surface whose outer diameter gradually increases from the tip side toward the base side. For this reason, compared with the case where the outer peripheral surface of the protruding portion is a cylindrical surface with a constant outer diameter from the tip side toward the base side, the volume of the space between the housing and the protruding portion in a state where the free protruding portion of the seal member contacts the valve seat can be reduced. Therefore, it is possible to suppress the occurrence of a liquid pooling phenomenon generated in the space between the housing and the protruding portion while suppressing a decrease in the seal surface pressure. In addition, it is possible to suppress the occurrence of freezing at low temperatures due to water pooling in the space between the housing and the protruding portion, and to suppress malfunction of the valve body.

[0013] The fourth means is the relief valve of the third means. The valve seat has a protrusion that can bite into the protruding portion in a line contact state. It is a relief valve.

[0014] According to the fourth means, by the protrusion of the valve seat biting into the protruding portion of the seal member in a line contact state, the seal surface pressure can be increased and the sealing performance can be improved.

Effects of the Invention

[0015] According to the technology disclosed in this specification, it is possible to suppress the occurrence of a liquid pooling phenomenon when the housing is installed horizontally on the member to be attached while miniaturizing the relief valve.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments for carrying out the technology disclosed in this specification will be described with reference to the drawings.

[0018] [Embodiment 1] In this embodiment, for example, a relief valve used in a fuel cell system for generating electric power for driving a motor mounted on a vehicle is exemplified. FIG. 1 is a front view showing the relief valve, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1, as viewed in the arrow direction. Note that the orientation related to the relief valve is defined as shown by the arrows in FIGS. 1 and 2, but it does not specify the arrangement direction of the relief valve.

[0019] As shown in FIG. 2, in the attached member 10, a hollow cylindrical relief hole 10a communicating with the hydrogen gas supply path of a fuel cell system (not shown) is formed. The relief hole 10a extends in the front-rear direction, that is, the horizontal direction. A plurality (two are shown, one above and one below in FIG. 2) of bolt holes 10b are formed in the attached member 10.

[0020] (Relief Valve 15) The relief valve 15 includes a housing 20, a valve body 30, and a spring 40. The relief valve 15 maintains the pressure of the hydrogen gas in the hydrogen gas supply path of the fuel cell system at a predetermined set pressure. The hydrogen gas corresponds to the "fluid" referred to in this specification.

[0021] (Housing 20) The housing 20 has a housing body 21 and a spring receiving member 26. The housing body 21 is formed in a substantially cylindrical shape. The front half of the housing body 21 is configured to be inserted into the relief hole 10a of the member to be attached 10 with a slight gap therebetween. The portion of the housing body 21 inserted into the relief hole 10a is referred to as a connection portion 22.

[0022] At the central portion in the axial direction of the housing body 21, a plurality (two in the up-and-down direction in this embodiment) of mounting pieces 23 protruding radially outward are formed (see FIG. 1). Bolt insertion holes 23a are formed in both mounting pieces 23. Both bolt insertion holes 23a respectively correspond to both bolt holes 10b of the member to be attached 10.

[0023] The housing body 21 has a valve seat 24 at the tip opening (left end opening in FIG. 2) of the connection portion 22. The valve seat 24 is formed in an annular shape protruding radially inward at the tip opening of the connection portion 22. The hollow portion of the valve seat 24 is a hydrogen gas inlet 25. The valve seat 24 is formed in a right-angled triangular cross-sectional shape having a seat surface 24a formed of a plane perpendicular to the axis 21L of the housing body 21 and a tapered surface 25a whose inner diameter gradually decreases from the inlet side (front side) to the outlet side (rear side) of the inlet 25. The wall surface of the inlet 25 is the tapered surface 25a.

[0024] The spring receiving member 26 is cylindrical and has an annular receiving portion 26a protruding radially inward at one end portion (rear end portion) thereof. The spring receiving member 26 is fitted into the other end portion (right end portion in FIG. 2) of the housing body 21 and fixed to the housing body 21 by caulking or the like. The hollow portion of the receiving portion 26a is an outlet 27.

[0025] An O-ring 28 made of rubber is mounted in an annular O-ring groove formed on the outer peripheral surface at the central portion in the axial direction of the connection portion 22 of the housing body 21.

[0026] (Valve body 30) The valve body 30 has a valve main body 31 and a seal member 37. The valve main body 31 is formed in a cylindrical shape with a bottom step. The valve main body 31 has a small-diameter cylindrical portion 32 formed in the front half, a large-diameter cylindrical portion 33 formed in the rear half, and an end plate portion 34 that closes the front-end opening of the small-diameter cylindrical portion 32. A plurality (four in this embodiment) of communication holes 35 penetrating in the radial direction are formed in the small-diameter cylindrical portion 32. An annular contact portion 36 is formed on the outer peripheral portion of the front surface of the end plate portion 34. Further, the seal member 37 is formed in a disc shape. The seal member 37 is attached to the valve main body 31 so as to fill the inside of the contact portion 36. The seal member 37 is made of rubber and has elasticity.

[0027] The valve body 30 is provided movably in the axial direction (front-rear direction) within the housing main body 21. The contact portion 36 can be seated on the valve seat 24. By the movement of the valve body 30, the contact portion 36 seats (comes into contact) and leaves the seat (separates) with respect to the valve seat 24. In FIG. 2, the closed valve state of the valve body 30, that is, the state where the front surface of the contact portion 36 is seated on the seat surface 24a of the valve seat 24, is shown.

[0028] (Spring 40) The spring 40 is a coil spring. The front end portion of the spring 40 is in contact with the stepped portion between the large-diameter cylindrical portion 33 and the small-diameter cylindrical portion 32 of the valve body 30. The rear end portion of the spring 40 is in contact with the receiving portion 26a of the spring receiving member 26. The spring 40 has elasticity to bias the valve body 30 leftward, that is, in the valve closing direction. Note that the housing 20, the spring receiving member 26, the valve main body 31, and the spring 40 are all made of metal.

[0029] (Attachment of the relief valve 15 to the attached member 10) As shown in FIG. 2, the connection portion 22 of the housing 20 is inserted into the relief hole 10a of the attached member 10. Thereby, the space between the attached member 10 and the connection portion 22 is elastically sealed by the O-ring 28. Further, bolts 12 are screwed into both bolt holes 10b of the attached member 10 through the bolt insertion holes 23a of both attachment pieces 23 of the housing 20, respectively. In this way, the relief valve 15 is attached to the attached member 10.

[0030] (Operation of Relief Valve 15) Normally, the valve body 30 is held in the closed state by the spring 40. In the closed state, the contact portion 36 is seated on the valve seat 24. Also, the space between the valve body 30 and the valve seat 24 is elastically sealed by the seal member 37.

[0031] When the hydrogen gas in the relief hole 10a, that is, the hydrogen gas supply path, exceeds a predetermined value, the valve body 30 is moved rearward against the biasing force of the spring 40 by that pressure and is thus opened. That is, the contact portion 36 and the seal member 37 of the valve body 30 are separated from the valve seat 24. As a result, the hydrogen gas is discharged from the discharge port 27 of the housing 20 through the relief hole 10a, through the gap between the housing body 21 and the valve body 30, the communication hole 35, and inside the valve body 31. Also, when the pressure of the hydrogen gas decreases, the valve body 30 is closed by the biasing force of the spring 40.

[0032] (Details of Seal Member 37) FIG. 3 is a cross-sectional view schematically showing a state during closing of the valve body 30. As used in this specification, the “state during closing of the valve body 30” refers to a state in which the front end of the seal member 37 in the free state is in contact with the seating surface 24a of the valve seat 24. As shown in FIG. 3, a bead portion 38 protrudes in an annular shape on the front surface of the seal member 37. In the free state of the seal member 37, the tip (top) of the bead portion 38 is in contact with the seating surface 24a of the valve seat 24. Also, when the contact portion 36 of the valve body 30 is seated on the seating surface 24a of the valve seat 24, the bead portion 38 is pushed into the contact portion 36 by utilizing the elasticity of the seal member 37. In this embodiment, the outer diameter of the seal member 37 is 37d, and the diameter passing through the apex of the bead portion 38 is 38d.

[0033] (Operation and Effect of Embodiment 1) According to Embodiment 1, the valve seat 24 of the housing 20 is formed in an annular shape that protrudes radially inward at one end opening (front end opening) of the housing 20 and has a hollow portion as the inlet 25. Therefore, by omitting the cylindrical portion of the body according to the conventional example and shortening the axial length of the housing 20, the relief valve 15 can be miniaturized.

[0034] Further, at least one end portion (front end portion) of the housing 20 is inserted into the relief hole 10a of the member to be attached 10, so that the amount of protrusion of the housing 20 from the member to be attached 10 can be reduced. This is effective in improving the mountability on the vehicle. Also, by designing the position of the attachment piece 23 with respect to the housing body 21 according to the surrounding situation of the relief valve 15, the amount of protrusion of the housing body 21 from the member to be attached 10 can be reduced.

[0035] Also, by omitting the cylindrical portion of the body according to the conventional example, the occurrence of a liquid pooling phenomenon (a water pooling phenomenon in this embodiment) when the housing 20 is installed in a horizontal state on the member to be attached 10 can be suppressed. Thereby, the occurrence of freezing at low temperatures due to water pooling can be suppressed.

[0036] Also, the wall surface of the inlet 25 is a tapered surface 25a whose inner diameter gradually decreases from the inlet side to the outlet side. Therefore, when the housing 20 is installed in a horizontal state on the member to be attached 10, the occurrence of a liquid pooling phenomenon occurring in the inlet 25 can be suppressed.

[0037] [Embodiment 2] Since this embodiment is a modification of the seal member 37 of Embodiment 1, the modified portion will be described. This embodiment is a related art related to the technology disclosed in this specification. The parts related to the modification of this embodiment are labeled with numbers in the 100s. In this embodiment, the bead portion 38 of the seal member 37 in Embodiment 1 (see FIG. 3) is omitted.

[0038] As shown in Fig. 4, the seal member 137 has an overhanging portion 138 that protrudes from the contact portion 36 of the valve body 30 in a free state. The outer peripheral portion of the front surface (the left side surface in Fig. 4) of the overhanging portion 138 is in surface contact with the seat surface 24a of the valve seat 24. The outer peripheral surface of the overhanging portion 138 is a cylindrical surface 138a with a constant outer diameter 138d. In the present embodiment, the outer diameter 138d is the same as the diameter 38d passing through the apex of the bead portion 38 in Embodiment 1 (see Fig. 3). Thus, by setting the outer diameter 138d of the overhanging portion 138 to be smaller than the outer diameter 37d of the seal member 37 in Embodiment 1 (see Fig. 3), it is possible to suppress a decrease in the seal surface pressure while the overhanging portion 138 is in surface contact with the seat surface 24a of the valve seat 24. Note that the outer diameter of the seal member 137 and the inner diameter of the contact portion 36 are the same as the outer diameter 138d of the overhanging portion 138.

[0039] [Embodiment 3] Since the present embodiment is a modification of the seal member 137 in Embodiment 2 (see Fig. 4), the modified portion will be described. The parts related to the modification of the present embodiment are labeled with numbers in the 200s. As shown in Fig. 5, the outer peripheral surface of the overhanging portion 238 of the seal member 237 is a tapered surface 238a whose outer diameter gradually increases from the tip side to the base side. In the present embodiment, the minimum diameter 238d of the overhanging portion 238 is the same as the outer diameter 138d of the overhanging portion 138 in Embodiment 2 (see Fig. 4). Also, the maximum diameter 238e of the overhanging portion 238 is the same as the outer diameter 37d of the seal member 37 in Embodiment 1 (see Fig. 3).

[0040] (Advantages of Embodiment 3) According to this embodiment, the outer peripheral surface of the protruding portion 238 that protrudes from the contact portion 36 in the free state of the seal member 237 is a tapered surface 238a whose outer diameter gradually increases from the tip side toward the base side. Therefore, compared with Embodiment 2 (see FIG. 4), the volume of the space S between the housing 20 and the protruding portion 238 in a state where the free protruding portion 238 of the seal member 237 is in surface contact with the seating surface 24a of the valve seat 24 can be reduced. Therefore, it is possible to suppress the occurrence of a liquid pooling phenomenon that occurs in the space S between the housing 20 and the protruding portion 238 without reducing the seal surface pressure. In addition, it is possible to suppress the occurrence of freezing at low temperatures due to water pooling in the space S between the housing 20 and the protruding portion 238, and suppress malfunction of the valve body 30.

[0041] [Embodiment 4] Since this embodiment is a modification of the valve seat 24 of the housing 20 in Embodiment 3 (see FIG. 5), the modified portion will be described. As shown in FIG. 6, a protrusion 24b that can bite into the protruding portion 238 of the seal member 237 in a line contact state is formed on the inner peripheral portion of the valve seat 24. The protrusion 24b is formed in a triangular cross-sectional shape with a sharp tip.

[0042] (Advantages of Embodiment 4) According to this embodiment, by the protrusion 24b of the valve seat 24 biting into the protruding portion 238 of the seal member 237 in a line contact state, the seal surface pressure can be increased and the sealing performance can be improved.

[0043] [Other Embodiments] The technology disclosed in this specification is not limited to the above-described embodiments, and can be implemented in various other forms. For example, the relief valve 15 may be used not only for hydrogen gas but also for controlling the pressure of various fluids such as gases and liquids. Also, the insertion amount of the housing body 21 with respect to the relief hole 10a may be increased or decreased according to the axial length of the relief hole 10a. Also, the wall surface of the inlet 25 may be a straight surface. Also, the number of sets of the bolt holes 10b, the bolts 12, and the attachment pieces 23 may be increased or decreased. Also, the attachment piece 23 may be omitted and the housing body 21 may be screwed into the relief hole 10a.

Description of Symbols

[0044] 10 Mounting member 10a Relief hole 15 Relief valve 20 Housing 24 Valve seat 24a Seat surface 24b Protrusion 25 Inlet 25a Tapered surface (wall surface) 30 Valve body 36 Contact portion 37 Sealing member 38 Bead portion 137 Sealing member 138 Overhanging portion 237 Sealing member 238 Overhanging portion 238a Tapered surface

Claims

1. A cylindrical housing attached to a member to be attached having a relief hole for fluid, A valve seat provided at one end of the housing, A valve body provided movably in the axial direction within the housing, which normally seats on the valve seat and separates from the valve seat by a pressure exceeding a predetermined value of the fluid, A relief valve comprising: The valve seat is formed in an annular shape that projects radially inward at an opening on one end side of the housing and has a hollow portion as an inlet for the fluid, At least one end portion of the housing is configured to be inserted into the relief hole. The relief valve.

2. The relief valve according to claim 1, wherein a wall surface of the inlet is a tapered surface whose inner diameter gradually decreases from an inlet side toward an outlet side. The relief valve.

3. The relief valve according to claim 1 or 2, An annular contact portion capable of seating on the valve seat is formed on the valve body, A disc-shaped seal member for elastically sealing between the valve body and the valve seat is provided within the contact portion, An outer peripheral surface of an overhanging portion that protrudes from the contact portion in a free state of the seal member is a tapered surface whose outer diameter gradually increases from a tip side toward a base side. The relief valve.

4. The relief valve according to claim 3, wherein the valve seat has a protrusion capable of biting into the overhanging portion in a line contact state. The relief valve.

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