pressure relief valve

Abstract

To provide a pressure release valve capable of suppressing deformation such as twisting.SOLUTION: A pressure release valve 10 comprises: a case 20 that includes a discharge hole 25 communicating with an opening part, and is fixed to a surface of a housing; a valve member 30 that includes a cover 31 covering the discharge hole in a closed position, and is movable from the closed position in a first direction to open the discharge hole; and a seal member 50 that is located between the case and the valve member, and surrounds the discharge hole in a plan view. The seal member includes: a body part; an inside seal 53 that is located inside the body part, and protrudes from the body part in the first direction; and an outside lip 54 that is located outside the body part, and protrudes from the body part in the first direction. A distance between the case and the valve member in the first direction in a space in which the seal member is arranged when the valve member is in the closed position is referred to as a reference distance. A ratio of a dimension of the outside lip in the first direction to the reference distance is 1.00 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure relief valve for regulating the pressure inside a housing. [Background technology]

[0002] A pressure relief valve is a device for adjusting the pressure inside a housing. The housing is, for example, a battery pack installed in an automobile. Devices such as battery cells are housed and sealed inside the battery pack. The pressure relief valve is attached to a housing such as a battery pack. For example, the pressure relief valve is arranged to cover an opening formed in the housing. When the pressure inside the housing exceeds a threshold, the pressure relief valve operates to release fluid inside the housing to the outside. The pressure relief valve can prevent damage to devices inside the housing due to an increase in pressure. This improves the safety of the battery pack.

[0003] Several pressure relief valves have been proposed. For example, the pressure relief valve disclosed in Patent Document 1 includes a case with a discharge hole formed therein and a cover that forms a passage for discharging gas discharged from the discharge hole. The case is provided with a valve mechanism that can open and close the discharge hole. An annular seal member is provided between the valve member of the valve mechanism and the case to seal the discharge hole from the outside. The seal member is pressed by the valve member and the case when the valve member is in a closed position.

[0004] The sealing member of a pressure relief valve may be hit by a high-energy fluid, such as a jet of high-pressure water cleaning. If the seal member is deformed, such as curled, by the impact of the fluid, it will be difficult to seal the discharge hole. To solve this problem, for example, Patent Document 2 proposes a sealing member that includes an annular inner seal and an annular outer seal that have the same cross-sectional shape. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7059226 [Patent Document 2] Patent No. 5093554 Summary of the Invention [Problem to be solved by the invention]

[0006] If the inner seal and outer seal have the same cross-sectional shape, the pressure from the valve member and case is distributed to both the inner seal and the outer seal. This reduces the pressure applied to each seal, which is thought to make it difficult to sufficiently prevent deformation such as curling.

[0007] An object of the present invention is to provide a pressure relief valve that can solve these problems. [Means for solving the problem]

[0008] The present invention relates to the following [1] to [9]. [1] A pressure relief valve that releases fluid from an opening in a housing when the internal pressure of the fluid inside the housing increases, a case fixed to a surface of the housing, the case including a discharge hole communicating with the opening; a valve member including a cover covering the drain hole in a closed position, the valve member being movable from the closed position in a first direction to open the drain hole; a seal member positioned between the case and the valve member and surrounding the discharge hole in a plan view, the seal member includes a main body portion, an inner seal located inside the main body portion and protruding from the main body portion in the first direction, and an outer seal located outside the main body portion and protruding from the main body portion in the first direction, a reference distance is a distance between the case and the valve member in the first direction in a space in which the seal member is disposed when the valve member is located at the closed position; a ratio of the dimension of the outer lip in the first direction to the reference distance being 1.00 or less;

[0009] [2] In the pressure relief valve described in [1], the inner seal may include a lower seal that protrudes from the main body portion toward the case and contacts the case in the closed position, and an upper seal that protrudes from the main body portion toward the valve member and contacts the valve member in the closed position.

[0010] [3] In the pressure relief valve according to [1] or [2], the dimension of the outer lip in the first direction may be smaller than the dimension of the inner seal in the first direction.

[0011] [4] In the pressure relief valve described in any one of [1] to [3], the outer lip may include a lower lip protruding from the main body portion toward the case, and a gap may be formed between the lower lip and the case in the closed position.

[0012] [5] In the pressure release valve according to any one of [1] to [3], a gap may be formed between the outer lip and the valve member in the closed position.

[0013] [6] In the pressure release valve described in [5], the main body may have a through-hole formed therein, the through-hole penetrating the main body in the first direction.

[0014] [7] A pressure relief valve that releases fluid from an opening in a housing when the internal pressure of the fluid inside the housing increases, a case fixed to a surface of the housing, the case including a discharge hole communicating with the opening; a valve member including a cover covering the drain hole in a closed position, the valve member being movable from the closed position in a first direction to open the drain hole; a seal member positioned between the case and the valve member and surrounding the discharge hole in a plan view, the seal member includes a main body portion, an inner seal located inside the main body portion and protruding from the main body portion in the first direction, and an outer seal located outside the main body portion and protruding from the main body portion in the first direction, A pressure relief valve, wherein the outer seal has a through hole formed therein that passes through the outer seal in a radial direction of the discharge hole.

[0015] [8] In the pressure relief valve described in [7], the inner seal and the outer seal may be in contact with the case and the valve member in the closed position, and the main body portion may have a through hole formed therein that penetrates the main body portion in the first direction.

[0016] [9] A pressure relief valve that releases fluid from an opening in a housing when the internal pressure of the fluid inside the housing increases, a valve member including a cover that covers the opening in a closed position and that is movable from the closed position in a first direction to open the opening; a seal member positioned between the housing and the valve member and surrounding the opening in a plan view, the seal member includes a main body portion, an inner seal located inside the main body portion and protruding from the main body portion in the first direction, and an outer seal located outside the main body portion and protruding from the main body portion in the first direction, a reference distance is a distance between the housing and the valve member in the first direction in a space in which the seal member is disposed when the valve member is located at the closed position; a ratio of the dimension of the outer lip in the first direction to the reference distance being 1.00 or less; [Effects of the Invention]

[0017] According to the present invention, deformation such as curling of the sealing member can be suppressed. [Brief explanation of the drawings]

[0018] [Figure 1]FIG. 2 is a partial cross-sectional view showing an example of a pressure relief valve. [Figure 2] FIG. 2 is a plan view illustrating an example of a sealing member. [Figure 3] FIG. 2 is a partial cross-sectional view showing an example of a sealing member. [Figure 4] FIG. 10 is a cross-sectional view illustrating an example of a seal member in a closed position. [Figure 5] FIG. 4 is a cross-sectional view showing an example of a seal member removed from a case and a valve member. [Figure 6] 10 is a cross-sectional view showing an example of the function of a sealing member. FIG. [Figure 7] 10 is a cross-sectional view showing an example of the function of a sealing member. FIG. [Figure 8] FIG. 10 is a cross-sectional view showing an example of the function of a sealing member in a comparative example. [Figure 9] FIG. 10 is a cross-sectional view showing an example of a seal member in a closed position in a first modified example. [Figure 10] FIG. 10 is a cross-sectional view showing an example of a seal member removed from a case and a valve member in a first modified example. [Figure 11] FIG. 10 is a cross-sectional view showing an example of a seal member in a closed position in a second modified example. [Figure 12] FIG. 11 is a cross-sectional view showing an example of a seal member in a closed position in a third modified example. [Figure 13] FIG. 13 is a cross-sectional view showing an example of a seal member in a closed position in a fourth modified example. [Figure 14] FIG. 11 is a cross-sectional view showing an example of a seal member removed from a case and a valve member in a fourth modified example. [Figure 15] FIG. 13 is a cross-sectional view showing an example of a seal member in a closed position in a fifth modified example. [Figure 16] FIG. 10 is a partial cross-sectional view showing a pressure release valve according to a sixth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described with reference to the accompanying drawings, in which the scale and aspect ratios of the drawings have been appropriately changed and exaggerated from those of the actual objects for ease of understanding.

[0020] FIG. 1 is a partial cross-sectional view showing an example of a pressure relief valve 10. The pressure relief valve 10 is attached to the surface of a housing (not shown). The housing is, for example, a battery pack mounted in an automobile. Devices such as battery cells are housed and sealed inside the battery pack. The housing includes an opening that penetrates the housing. The pressure relief valve 10 is attached to the surface of the housing so as to cover the opening.

[0021] The pressure relief valve 10 operates to release fluid such as gas inside the housing to the outside when the pressure inside the housing exceeds a threshold. The pressure inside the housing is also referred to as internal pressure.

[0022] The pressure release valve 10 comprises a case 20 including a discharge hole 25 communicating with the opening, a valve member 30 covering the discharge hole 25 of the case 20, and an elastic member 40 biasing the valve member 30. The pressure release valve 10 further comprises a seal member 50. The seal member 50 is located between the case 20 and the valve member 30. The pressure release valve 10 may further comprise a second seal member 60. The second seal member 60 is located between the case 20 and the surface of the housing.

[0023] (case) The case 20 includes a lower surface 21 facing the surface of the housing and an upper surface 22 located on the opposite side of the lower surface 21 in the first direction D1. For example, the case 20 includes a plate including the lower surface 21 and the upper surface 22. The first direction D1 is a normal direction to the surface of the housing. The term "lower" used with respect to components of the pressure relief valve 10 means that the component is relatively close to the housing. Conversely, the term "upper" means that the component is relatively far from the housing. For example, the distance from the lower surface 21 of the case 20 to the housing is smaller than the distance from the upper surface 22 of the case 20 to the housing.

[0024] The upper surface 22 includes a main surface 23. The main surface 23 may include an area that does not overlap the valve member 30 in a plan view. "Plan view" means that an object is viewed along the normal direction of the surface of the housing. The upper surface 22 may include a groove 24 that is recessed downward relative to the main surface 23. The above-mentioned seal member 50 may be disposed in the groove 24.

[0025] (Valve member) The valve member 30 is configured to be movable in a first direction D1 from a closed position to an open position. The valve member 30 includes at least a cover 31. The cover 31 includes a lower surface 311 and an upper surface 312. When the valve member 30 is in the closed position, the cover 31 covers the discharge hole 25 of the case 20. When the cover 31 moves in the first direction D1 from the closed position to the open position, the discharge hole 25 is opened, and fluid such as high-pressure gas is discharged from the inside of the housing to the outside.

[0026] The valve member 30 may include a shaft 32 extending downward from the lower surface 311 of the cover 31. The shaft 32 may be inserted into the elastic member 40.

[0027] (elastic member) When the valve member 30 is in the closed position, the elastic member 40 biases the valve member 30 toward the case 20 and the housing in the first direction D1. The elastic member 40 expands and contracts in the first direction D1 in response to movement of the valve member 30 in the first direction D1. The elastic member 40 is, for example, a spring. When the force that the valve member 30 receives from the internal pressure of the housing in the first direction D1 becomes greater than the biasing force that the valve member 30 receives from the elastic member 40, the valve member 30 moves from the closed position toward the open position.

[0028] (Sealing material) The seal member 50 is a member for more reliably sealing the inside of the housing when the valve member 30 is in the closed position. The seal member 50 can prevent dust, water, etc. from entering the inside of the housing from the outside. The seal member 50 is located between the lower surface 311 of the cover 31 and the upper surface 22 of the case 20.

[0029] 1, the seal member 50 includes an inner seal 53 and an outer lip 54. "Outer" refers to a direction away from the center of the discharge hole 25 in a plan view. "Inner" refers to a direction toward the center of the discharge hole 25 in a plan view. The outer lip 54 is located outward of the inner seal 53.

[0030] Fig. 2 is a plan view showing an example of seal member 50. In Fig. 2, discharge hole 25 is drawn with a dotted line to show the positional relationship of discharge hole 25 with respect to seal member 50. Seal member 50 surrounds discharge hole 25 in plan view.

[0031] 3 is a partial cross-sectional view showing an example of a seal member 50. As shown in Figures 2 and 3, the seal member 50 may include an inner main body portion 51, an outer main body portion 52, an inner seal 53, an outer lip 54, and a main body portion 55. The inner main body portion 51, the outer main body portion 52, the inner seal 53, the outer lip 54, and the main body portion 55 have an annular shape surrounding the discharge hole 25 in a plan view.

[0032] The shape of the seal member 50 is not particularly limited as long as the seal member 50 surrounds the discharge hole 25 in a plan view. For example, the seal member 50 may be circular or elliptical in a plan view. In the following description, the direction from the center of the seal member 50 to the outside in a plan view is also referred to as the radial direction.

[0033] 4 is a cross-sectional view showing an example of a seal member 50 in the closed position. The main body portion 55 connects the inner seal 53 and the outer lip 54. The main body portion 55 includes a lower surface 551 and an upper surface 552. The inner seal 53 is located inward of the main body portion 55 and protrudes from the main body portion 55 in the first direction D1. For example, the inner seal 53 includes a lower seal 531 that protrudes downward from the lower surface 551 and an upper seal 532 that protrudes upward from the upper surface 552. The outer lip 54 is located outward of the main body portion 55 and protrudes from the main body portion 55 in the first direction D1. For example, the outer lip 54 includes a lower lip 541 that protrudes downward from the lower surface 551 and an upper lip 542 that protrudes upward from the upper surface 552.

[0034] The inner main body portion 51 protrudes inward from the inner seal 53. The inner main body portion 51 includes a lower surface 511 and an upper surface 512. The lower surface 511 of the inner main body portion 51 may be located on the same plane as the lower surface 551 of the main body portion 55. The upper surface 512 of the inner main body portion 51 may be located on the same plane as the upper surface 552 of the main body portion 55. The inner seal 53 protrudes from the inner main body portion 51 in the first direction D1.

[0035] The outer body portion 52 protrudes outward from the outer lip 54. The outer body portion 52 includes a lower surface 521 and an upper surface 5222. The lower surface 521 of the outer body portion 52 may be located on the same plane as the lower surface 551 of the body portion 55. The upper surface 522 of the outer body portion 52 may be located on the same plane as the upper surface 552 of the body portion 55. The outer lip 54 protrudes from the outer body portion 52 in the first direction D1.

[0036] 4 indicates the distance (also referred to as the reference distance) between the upper surface 22 of the case 20 and the lower surface 311 of the cover 31 of the valve member 30 in the first direction D1 when the valve member 30 is in the closed position. The reference distance S0 is defined in the space in which the outer lip 54 of the seal member 50 is disposed. In this embodiment, since the seal member 50 is disposed in the groove 24 of the case 20, the reference distance S0 is the distance between the bottom surface of the groove 24 and the lower surface 311 of the cover 31.

[0037] Reference numeral 57 in Fig. 4 denotes a space (also referred to as a first space) located between the main body 55 and the case 20 in the first direction D1, and located between the inner seal 53 and the outer lip 54 in a plan view. Reference numeral 58 in Fig. 4 denotes a space (also referred to as a second space) located between the main body 55 and the valve member 30 in the first direction D1, and located between the inner seal 53 and the outer lip 54 in a plan view.

[0038] As shown in FIG. 4, the lower seal 531 of the inner seal 53 contacts the groove 24 of the case 20. The upper seal 532 of the inner seal 53 contacts the underside 311 of the cover 31. As described above, the valve member 30 receives a biasing force from the elastic member 40 toward the case 20. Therefore, the valve member 30 presses the seal member 50 toward the case 20. As a result, the seal member 50 is elastically compressed in the first direction D1. The reference distance S0 is determined so that the force of the valve member 30 pressing the seal member 50 toward the case 20 and the elastic restoring force generated in the seal member 50 are balanced.

[0039] Of the two surfaces that the seal member 50 comes into contact with, the surface that can move relative to the housing, such as the underside 311 of the cover 31, is also referred to as the moving surface and is indicated by the reference numeral 72. Of the two surfaces that the seal member 50 comes into contact with, the surface that remains stationary relative to the housing, such as the bottom surface of the groove 24 of the case 20, is also referred to as the stationary surface and is indicated by the reference numeral 71.

[0040] 4, the upper lip 542 of the outer lip 54 may be in contact with the lower surface 311 of the cover 31. In this case, the second space 58 is sealed. On the other hand, the lower lip 541 of the outer lip 54 does not have to be in contact with the bottom surface of the groove 24 of the case 20. For example, a gap 543 may be formed between the lower lip 541 and the bottom surface of the groove 24 of the case 20. In this case, the first space 57 communicates with the external space via the gap 543.

[0041] 5 is a cross-sectional view showing an example of a seal member 50 removed from the case 20 and the valve member 30. The inner seal 53 of the seal member 50 has a dimension S1 (also referred to as a first longitudinal dimension) in the first direction D1. The outer lip 54 of the seal member 50 has a dimension S2 (also referred to as a second longitudinal dimension) in the first direction D1. The second longitudinal dimension S2 may be smaller than the first longitudinal dimension S1. The ratio S2 / S1 of the second longitudinal dimension S2 to the first longitudinal dimension S1 is, for example, 0.98 or less, or may be 0.95 or less, or may be 0.90 or less.

[0042] The second vertical dimension S2 of the outer lip 54 may be equal to or less than the reference distance S0, thereby preventing the first space 57 and the second space 58 from being tightly sealed. The ratio S2 / S0 of the second vertical dimension S2 to the reference distance S0 is, for example, equal to or less than 1.00, and may be equal to or less than 0.95, or may be equal to or less than 0.90.

[0043] The first vertical dimension S1 of the inner seal 53 is greater than the reference distance S0. The ratio S1 / S0 of the first vertical dimension S1 to the reference distance S0 is, for example, 1.02 or greater, or may be 1.05 or greater, or may be 1.10 or greater.

[0044] Next, the function of the seal member 50 when the valve member 30 is in the closed position will be described with reference to FIGS.

[0045] When the valve member 30 is in the closed position, as shown in FIG. 6, a fluid F may collide with the valve member 30 from the outside. The fluid F may be, for example, a jet of high-pressure cleaning water. The fluid F is particularly likely to collide with the lower lip 541 of the outer lip 54. When the fluid F collides with the lower lip 541, the lower lip 541 tilts inward. When the lower lip 541 tilts inward, the first space 57 becomes narrower.

[0046] In the present embodiment, a gap 543 is formed between the lower lip 541 and the case 20. Because the first space 57 communicates with the external space via the gap 543, even if the first space 57 becomes narrow, an increase in pressure in the first space 57 can be suppressed. This can suppress the lower seal 531 of the inner seal 53 from being pressed inward. This can suppress deformation, such as curling, of the inner seal 53.

[0047] Furthermore, in this embodiment, the second vertical dimension S2 of the outer lip 54 is equal to or shorter than the reference distance S0. Therefore, the pressing force applied from the valve member 30 to the outer lip 54 can be made smaller than the pressing force applied from the valve member 30 to the inner seal 53. This ensures that the pressing force applied from the valve member 30 to the inner seal 53 is sufficiently large. Therefore, even if the fluid F collides with the inner seal 53 from the outside, deformation such as curling up of the inner seal 53 can be suppressed.

[0048] As the jet becomes stronger, the inclination of the lower lip 541 increases. When the inclination of the lower lip 541 increases, the inclined lower lip 541 comes into contact with the case 20, as shown in FIG. 7. This prevents the lower lip 541 from tilting further inward. In the state shown in FIG. 7, the outer lip 54 is only lightly in contact with the case 20 and the valve member 30. Even in the state shown in FIG. 7, the pressing force applied from the valve member 30 to the outer lip 54 is smaller than the pressing force applied from the valve member 30 to the inner seal 53.

[0049] FIG. 8 is a cross-sectional view showing an example of the function of the seal member 50 in a comparative embodiment. In the comparative embodiment, the outer lip 54 has the same cross-sectional shape as the inner seal 53. In this case, the pressing force applied from the valve member 30 to the outer lip 54 is the same as the pressing force applied from the valve member 30 to the inner seal 53. That is, in the comparative embodiment, the pressing force applied from the valve member 30 to the seal member 50 is evenly distributed to the inner seal 53 and the outer lip 54. Therefore, the pressing force applied from the valve member 30 to the inner seal 53 in the comparative embodiment is smaller than the pressing force applied from the valve member 30 to the inner seal 53 in this embodiment. Therefore, deformation such as curling is likely to occur in the inner seal 53.

[0050] In contrast, in the present embodiment, the pressing force applied from the valve member 30 to the sealing member 50 is preferentially distributed to the inner seal 53. This makes it possible to prevent deformation such as curling of the inner seal 53. This can therefore improve the safety of the housing of the battery pack or the like.

[0051] It should be noted that various modifications can be made to the above-described embodiment. Below, modifications will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the above-described embodiment, and duplicated explanations will be omitted. Furthermore, if it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified embodiment, the explanations thereof may be omitted.

[0052] (First Modification) Fig. 9 is a cross-sectional view showing an example of the seal member in the closed position in the first modified example. As shown in Fig. 9, the distance between the case 20 and the valve member 30 in the space where the outer lip 54 is disposed may be greater than the distance between the case 20 and the valve member 30 in the space where the inner seal 53 is disposed. For example, a step may be formed on the surface of the case 20 or the valve member 30 located between the inner seal 53 and the outer lip 54 in a plan view. In the example shown in Fig. 9, a step 241 is formed on the bottom surface of the groove 24 of the case 20 located between the inner seal 53 and the outer lip 54 in a plan view.

[0053] FIG. 10 is a cross-sectional view showing an example of the seal member 50 removed from the case 20 and valve member 30 shown in FIG. 9. The outer lip 54 may have the same cross-sectional shape as the inner seal 53. For example, the second vertical dimension S2 may be the same as the first vertical dimension S1. Even in this case, according to this modification, the second vertical dimension S2 of the outer lip 54 can be set to be equal to or less than the reference distance S0. Therefore, for example, a gap 543 can be formed between the lower lip 541 and the case 20. Therefore, as in the above-described embodiment, deformation such as curling can be suppressed in the inner seal 53.

[0054] (Second Modification) FIG. 11 is a cross-sectional view showing an example of the seal member 50 in the closed position in the second modified example. In this modified example, as in the above-described embodiment, the second vertical dimension S2 of the outer lip 54 is equal to or less than the reference distance S0. Therefore, a gap is formed between the outer lip 54 and the case 20 or the valve member 30. As shown in FIG. 11, a gap 543 may be formed between the upper lip 542 of the outer lip 54 and the lower surface 311 of the cover 31. This allows the pressing force applied from the valve member 30 to the outer lip 54 to be smaller than the pressing force applied from the valve member 30 to the inner seal 53. This ensures a sufficiently large pressing force applied from the valve member 30 to the inner seal 53. Furthermore, because the second space 58 is connected to the external space, an increase in pressure in the second space 58 can be suppressed. This prevents deformation, such as curling, of the inner seal 53.

[0055] As shown in Fig. 11, a through-hole 553 may be formed penetrating the main body 55 in the first direction D1. This allows the first space 57 to communicate with the external space via the second space 58. Therefore, even if the first space 57 becomes narrow, an increase in pressure in the first space 57 can be suppressed. This prevents the lower seal 531 of the inner seal 53 from being pressed inward. This prevents deformation, such as curling, from occurring in the inner seal 53. Furthermore, it is possible to prevent the generation of a force that pushes up the valve member 30.

[0056] There are no particular limitations on the number and arrangement of the through holes 553. For example, the seal member 50 may include a plurality of through holes 553 arranged in the circumferential direction of the seal member 50.

[0057] (Third Modification) Fig. 12 is a cross-sectional view showing an example of the seal member 50 in the closed position in the third modified example. As shown in Fig. 12, the outer lip 54 includes a lower lip 541 but does not necessarily include an upper lip 542. This makes it possible to suppress an increase in pressure in the second space 58, as in the second modified example. Therefore, it is possible to suppress deformation, such as curling, of the inner seal 53. Although not shown, a through hole 553 may be formed in this modified example, penetrating the main body portion 55 in the first direction D1.

[0058] (Fourth Modification) 13 is a cross-sectional view showing an example of the seal member 50 in the closed position in the fourth modified example. As shown in FIG. 13, the lower lip 541 of the outer lip 54 may be in contact with the case 20, and the upper lip 542 may be in contact with the valve member 30.

[0059] FIG. 14 is a cross-sectional view showing an example of the seal member 50 removed from the case 20 and valve member 30 shown in FIG. 13. In this modified example, as in the above-described embodiment, the second vertical dimension S2 of the outer lip 54 is equal to or less than the reference distance S0. Furthermore, the second vertical dimension S2 is smaller than the first vertical dimension S1. Therefore, in the state shown in FIG. 13, the outer lip 54 only lightly touches the case 20 and the valve member 30. Even in the state shown in FIG. 13, the pressing force applied from the valve member 30 to the outer lip 54 is smaller than the pressing force applied from the valve member 30 to the inner seal 53. Therefore, the pressing force applied from the valve member 30 to the inner seal 53 can be ensured to be sufficiently large. Therefore, deformation such as curling of the inner seal 53 can be suppressed.

[0060] (Fifth Modification) FIG. 15 is a cross-sectional view showing an example of the seal member 50 in the closed position in the fifth modified example. As shown in FIG. 15, the outer seal 54 may be formed with a through-hole 544 that penetrates the outer lip 54 in the radial direction of the discharge hole 25. In the example shown in FIG. 15, the through-hole 544 is formed in the lower lip 541 of the outer lip 54. Therefore, the first space 57 can communicate with the external space via the through-hole 544. As a result, even if the first space 57 becomes narrow, an increase in pressure in the first space 57 can be suppressed. Therefore, the lower seal 531 of the inner seal 53 can be suppressed from being pressed inward. As a result, deformation such as curling can be suppressed from occurring in the inner seal 53.

[0061] There are no particular limitations on the number and arrangement of the through holes 544. For example, the seal member 50 may include a plurality of through holes 544 arranged in the circumferential direction of the seal member 50.

[0062] In this modification, the ratio S2 / S0 of the second longitudinal dimension S2 to the reference distance S0 may be equal to or less than 1.00 or may exceed 1.00. Preferably, the second longitudinal dimension S2 of the outer lip 54 is smaller than the first longitudinal dimension S1 of the inner seal 53.

[0063] (Sixth Modification) In the above-described embodiment and modified examples, an example was described in which the seal member 50 was positioned between the case 20 and the valve member 30. In this modified example, an example in which the seal member 50 is positioned between the housing and the valve member 30 will be described.

[0064] 16 is a partial cross-sectional view showing a pressure relief valve 10 according to this modification. The pressure relief valve 10 is attached to a surface 82 of a housing 80. The housing 80 includes an opening 85 penetrating the housing 80. The surface 82 of the housing 80 may include a groove 84 recessed downward relative to a main surface 83.

[0065] The valve member 30 is configured to be movable in a first direction D1 from a closed position to an open position. When the valve member 30 is in the closed position, the cover 31 of the valve member 30 covers an opening 85 of the housing 80. In the closed position, the cover 31 faces a main surface 83 of a surface 82 of the housing 80. When the cover 31 moves in the first direction D1 from the closed position to the open position, the opening 85 is opened, and a fluid such as high-pressure gas is discharged from the inside of the housing 80 to the outside.

[0066] The seal member 50 is positioned between the housing 80 and the valve member 30. The seal member 50 may be disposed in a groove 84 of the housing 80. As in the above-described embodiment, the seal member 50 includes at least an inner seal 53, an outer lip 54, and a main body 55. When the valve member 30 is in the closed position, the lower seal of the inner seal 53 contacts a surface 82 of the housing 80, and the upper seal of the inner seal 53 contacts a lower surface 311 of the cover 31. In this modified example, the surface 82 of the housing 80 is the stationary surface 71. In this modified example, the space located between the main body 55 and the housing 80 in the first direction D1 and between the inner seal 53 and the outer lip 54 in a plan view is the first space. In this modified example, when the valve member 30 is in the closed position, the distance between the surface 82 of the housing 80 and the lower surface 311 of the cover 31 of the valve member 30 in the first direction D1 is the reference distance S0.

[0067] The configuration of the outer lip 54 may be the same as the configuration of the outer lip 54 in the above-described embodiment. For example, when the valve member 30 is in the closed position, a gap may be formed between the lower lip of the outer lip 54 and the bottom surface of the groove 84 in the housing 80. Because the first space communicates with the external space via the gap, even if the first space becomes narrow, an increase in pressure in the first space can be suppressed. This prevents the lower seal of the inner seal 53 from being pressed inward. This prevents deformation, such as curling, of the inner seal 53.

[0068] The configuration of the outer lip 54 may be the same as the configuration of the outer lip 54 in any of the variations described above.

[0069] (Other variations) Several variations may be combined with the above-described embodiments. [Explanation of symbols]

[0070] 10 Pressure relief valve 20 cases 21 Bottom side 22 Top side 24 groove 25 Discharge hole 30 Valve member 31 Cover 311 Bottom surface 312 Top surface 40 Elastic member 50 sealing material 53 Inner seal 531 Lower seal 532 Upper seal 54 outer lip 541 Lower lip 542 Upper lip 543 Gap 544 Through hole 55 Main body 551 Bottom side 552 Top surface 553 Through hole 60 second seal member 80 cabinets 82 Surface 84 Ditch 85 Opening

Claims

1. A pressure relief valve that releases fluid from an opening in the housing when the internal pressure of the fluid inside the housing increases, a case fixed to a surface of the housing, the case including a discharge hole communicating with the opening; a valve member including a cover that covers the drain hole in a closed position and that is movable relative to the housing in a first direction from the closed position to open the drain hole; a seal member positioned between the case and the valve member and surrounding the discharge hole in a plan view, the seal member includes a main body portion, an inner seal located inside the main body portion and protruding from the main body portion in the first direction, and an outer lip located outside the main body portion and protruding from the main body portion in the first direction, When the valve member is in the closed position, the inner seal contacts the case and the valve member; a reference distance is a distance between the case and the valve member in the first direction in a space in which the seal member is disposed when the valve member is located at the closed position; a ratio of the dimension of the outer lip in the first direction to the reference distance is 1.00 or less.

2. 2. The pressure relief valve of claim 1, wherein the inner seal includes a lower seal that projects from the body portion toward the case and contacts the case in the closed position, and an upper seal that projects from the body portion toward the valve member and contacts the valve member in the closed position.

3. 2. The pressure relief valve of claim 1, wherein a dimension of the outer lip in the first direction is smaller than a dimension of the inner seal in the first direction.

4. the outer lip includes a lower lip that protrudes from the body portion toward the case; 4. The pressure relief valve according to claim 2, wherein a gap is formed between the lower lip and the case in the closed position.

5. 4. The pressure relief valve of claim 2, wherein a gap is formed between the outer lip and the valve member in the closed position.

6. The pressure relief valve according to claim 5 , wherein the main body portion has a through-hole formed therein that penetrates the main body portion in the first direction.

7. A pressure relief valve that releases fluid from an opening in the housing when the internal pressure of the fluid inside the housing increases, a case fixed to a surface of the housing, the case including a discharge hole communicating with the opening; a valve member including a cover that covers the drain hole in a closed position and that is movable relative to the housing in a first direction from the closed position to open the drain hole; a seal member positioned between the case and the valve member and surrounding the discharge hole in a plan view, the seal member includes a main body portion, an inner seal located inside the main body portion and protruding from the main body portion in the first direction, and an outer lip located outside the main body portion and protruding from the main body portion in the first direction, When the valve member is in the closed position, the inner seal contacts the case and the valve member; A pressure relief valve, wherein the outer lip has a through hole formed therein that passes through the outer lip in a radial direction of the discharge hole.

8. the inner seal and the outer lip contact the case and the valve member in the closed position; The pressure relief valve according to claim 7 , wherein the main body portion has a through-hole formed therein that penetrates the main body portion in the first direction.

9. A pressure relief valve that releases fluid from an opening in the housing when the internal pressure of the fluid inside the housing increases, a valve member including a cover that covers the opening in a closed position and that is movable relative to the housing in a first direction from the closed position to open the opening; a seal member positioned between the housing and the valve member and surrounding the opening in a plan view, the seal member includes a main body portion, an inner seal located inside the main body portion and protruding from the main body portion in the first direction, and an outer lip located outside the main body portion and protruding from the main body portion in the first direction, when the valve member is in the closed position, the inner seal contacts the housing and the valve member; a reference distance is a distance between the housing and the valve member in the first direction in a space in which the seal member is disposed when the valve member is located at the closed position; a ratio of the dimension of the outer lip in the first direction to the reference distance is 1.00 or less.

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