Pressure relief valve

Abstract

To provide a pressure release valve capable of suppressing the height in the axial direction.SOLUTION: The pressure release valve 2 includes the base member 5 inserted into the opening 91 formed in the case 9 and fixed to the edge portion 92 of the opening 91 and having the vent hole 512 communicating the internal space of the case 9 with the external space of the case 9 and the valve seat 511, the valve member 4 having the shaft portion 415 prevented from coming off from the base member 5, the seal portion 42 coming into contact with and separating from the valve seat 511 to open and close the vent hole 512, and the first engaging portion 414 provided outside the shaft portion 415 in the radial direction, and the cap 3 covering the valve seat 511 and the seal portion 42 with the seal portion 42 in contact with the valve seat 511 to close the vent hole 512 and having the second engaging portion 312 engaging with the first engaging portion 414 by rotating in the first direction around the shaft portion 415.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pressure relief valve that is attached to a case that houses, for example, an electricity storage device, and that relieves pressure inside the case. [Background technology]

[0002] Hybrid vehicles and electric vehicles generally use power storage devices such as batteries and capacitors. The power storage device is housed inside a case installed inside the vehicle. When the power storage device is a battery such as a lithium-ion battery, a chemical reaction in the battery's electrolyte can generate gas, causing the pressure inside the case to increase. Therefore, a pressure relief valve is attached to the case to reduce the pressure inside the case.

[0003] Patent Document 1 discloses a pressure release device for a battery pack. The protective cover of the pressure release device described in Patent Document 1 has a snap receiver. The snap receiver has a snap hole. The snap hole is provided near the bottom end of the snap receiver, extends through the inner and outer surfaces of the snap receiver, and fits into a snap member on the mounting base. This allows the protective cover to be snapped onto the mounting base from top to bottom.

[0004] However, the pressure release device described in Patent Document 1 has the problem that it is difficult to keep the axial height of the pressure release device low because the protective cover is snapped onto the mounting base from top to bottom. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-93355 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a pressure relief valve whose axial height can be kept low. [Means for solving the problem]

[0007] One aspect of the present invention is a pressure release valve comprising: a base member that is inserted into an opening formed in a case and fixed to the edge of the opening, has a vent hole that connects the internal space of the case with the external space of the case, and has a valve seat; a valve member that has an axial portion that prevents the valve member from coming out of the base member, a seal portion that moves toward and away from the valve seat to open and close the vent hole, and a first engagement portion that is located radially outward from the axial portion; and a cap that covers the valve seat and the seal portion with the seal portion in contact with the valve seat to close the vent hole, and has a second engagement portion that engages with the first engagement portion by rotating in a first direction around the axial portion.

[0008] According to one aspect of the present invention, the first engagement portion of the valve member is located radially outward from the axial portion of the valve member. The second engagement portion of the cap engages with the first engagement portion of the valve member by rotating in a first direction around the axial portion of the valve member. In this way, the cap having the second engagement portion engages with the valve member having the first engagement portion by rotating in the first direction around the axial portion of the valve member. This allows the axial height of the pressure release valve of the present invention to be kept low compared to when the cap is attached to the valve member along the axis. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a pressure relief valve whose axial height can be kept low. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing a pressure relief valve according to the present embodiment. [Figure 2] FIG. 2 is an exploded view illustrating the pressure relief valve according to the present embodiment. [Figure 3]FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 4] 2 is a cross-sectional view taken along the cutting plane BB shown in FIG. 1. [Figure 5] FIG. 10 is a cross-sectional view showing a pressure release valve according to a modified example of the present embodiment. [Figure 6] FIG. 2 is a perspective view illustrating a valve member according to the present embodiment. [Figure 7] FIG. 2 is a perspective view illustrating a cap according to the present embodiment. [Figure 8] FIG. 2 is a perspective view illustrating a state before the cap of the present embodiment is placed on the valve member. [Figure 9] 10 is a perspective view showing a state before an engaging portion of the cap and an engaging portion of the valve member are engaged with each other. FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along a cutting plane CC shown in FIG. [Figure 11] FIG. 10 is a cross-sectional view taken along a cutting plane DD shown in FIG. 9. [Figure 12] 10 is a perspective view showing a state after the engaging portion of the cap and the engaging portion of the valve member have engaged with each other. FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along the cutting plane EE shown in FIG. [Figure 14] 13 is a cross-sectional view taken along the cutting plane FF shown in FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiments described below are preferred examples of the present invention, and therefore various technically preferable limitations are applied thereto, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is particularly limited. Furthermore, in each drawing, similar components are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0012] FIG. 1 is a perspective view showing a pressure relief valve according to this embodiment. FIG. 2 is an exploded view showing the pressure relief valve according to this embodiment. FIG. 3 is a cross-sectional view taken along the cutting plane AA shown in FIG. FIG. 4 is a cross-sectional view taken along the cutting plane BB shown in FIG.

[0013] The pressure release valve 2 of this embodiment is attached to a case 9 that houses an electricity storage device or the like, and when the pressure inside the case 9 increases, it releases the gas inside the case 9 and releases the pressure inside the case 9.

[0014] Examples of the power storage device housed in case 9 include batteries (lithium ion batteries, etc.) used in hybrid vehicles including plug-in hybrid vehicles, electric vehicles, etc. However, the power storage device housed in case 9 is not limited to these. Furthermore, the contents housed in case 9 are not limited to power storage devices.

[0015] 2, the case 9 has an opening 91. An edge 92 of the opening 91 has a flange 922. The flange 922 protrudes radially inward from an inner circumferential surface 921 of the edge 92. Here, in this specification, the "front side" refers to the side of the case 9 facing the external space S2 (see FIG. 3) of the case 9, or the direction from the internal space S1 (see FIG. 3) of the case 9 toward the external space S2 of the case 9. Also, in this specification, the "rear side" refers to the side of the case 9 facing the internal space S1 of the case 9, or the direction from the external space S2 of the case 9 toward the internal space S1 of the case 9.

[0016] As shown in FIG. 2, the pressure release valve 2 includes a cap 3, a valve member 4, a base member 5, a sealing ring 6, a biasing member 7, and a locking member 8.

[0017] The base member 5 is fixed to the edge 92 of the opening 91 of the case 9 by rotating in a first direction A11 (see FIG. 1) about the axis A1. The base member 5 is released from the edge 92 of the opening 91 of the case 9 by rotating in a second direction A12 (see FIG. 1) about the axis A1, i.e., the direction opposite to the first direction A11.

[0018] The axis A1 is the axis of the base member 5, as well as the axes of the cap 3, the valve member 4, the seal ring 6, the biasing member 7, and the locking member 8. In other words, the axis of the base member 5 coincides with the axes of the cap 3, the valve member 4, the seal ring 6, the biasing member 7, and the locking member 8.

[0019] As shown in FIG. 2, the base member 5 has an annular portion 51, a ceiling portion 52, and a rib 53. The annular portion 51 has a substantially circular ring shape and forms the radially outermost portion of the base member 5. The annular portion 51 has a valve seat 511. The valve seat 511 has a front surface, i.e., a surface facing the seal portion 42 of the valve member 4. As shown in FIGS. 3 and 4, when the base member 5 is fixed to the edge portion 92 of the opening 91 of the case 9, the valve seat 511 is disposed on the periphery of the opening 91 of the case 9.

[0020] The ceiling portion 52 has a disk shape and is provided inside the annular portion 51. Specifically, the ceiling portion 52 is provided on the front side of the annular portion 51 in the radial center of the base member 5. The ceiling portion 52 has a through hole 521. The through hole 521 is formed in the radial center of the ceiling portion 52 and penetrates the ceiling portion 52 in the direction of the axis A1.

[0021] The rib 53 is connected to the ceiling portion 52 and the insertion portion 54 (see FIGS. 3 and 4). That is, the ceiling portion 52 is connected to the insertion portion 54 via the rib 53. The insertion portion 54 is the portion that is inserted into the opening 91 of the case 9, and is connected to the inner circumferential surface 513 of the annular portion 51 (see FIG. 3). As a result, the ceiling portion 52 is connected to the annular portion 51 via the rib 53 and the insertion portion 54.

[0022] 2, the base member 5 of this embodiment has a plurality of ribs 53. The plurality of ribs 53 are spaced apart from one another in the circumferential direction. Ventilation holes 512 are formed between adjacent ribs 53. The ventilation holes 512 communicate between an internal space S1 of the case 9 and an external space S2 of the case 9.

[0023] The valve member 4 has a base portion 41 and a seal portion 42. The base portion 41 is formed from a material harder than the material of the seal portion 42, and has a ceiling portion 411, a peripheral wall portion 412, and a flange portion 413. The ceiling portion 411 has a disk shape and is provided in the radial center of the valve member 4.

[0024] The peripheral wall portion 412 is connected to the outer peripheral edge of the ceiling portion 411 and extends from the outer peripheral edge of the ceiling portion 411 toward the back side, i.e., the side of the base member 5. The flange portion 413 is connected to the tip of the peripheral wall portion 412 in the extension direction and extends radially outward from the tip of the peripheral wall portion 412 in the extension direction.

[0025] The seal portion 42 is made of an elastic material such as rubber or an elastic elastomer, and is formed integrally with the flange portion 413 of the base portion 41. The seal portion 42 extends radially outward from the outer peripheral edge of the flange portion 413 and also extends from the outer peripheral edge of the flange portion 413 toward the back side, i.e., the side of the base member 5. The seal portion 42 moves toward and away from the valve seat 511 of the base member 5 to open and close the vent hole 512.

[0026] The base 41 further has an engagement portion 414 and a shaft portion 415. The engagement portion 414 is an example of a "first engagement portion" of the present invention. The engagement portion 414 is provided on the front surface of the ceiling portion 411 and is formed to extend in the circumferential direction near the outer circumferential edge of the ceiling portion 411. As shown in FIG. 3, the engagement portion 414 is provided radially outward of the shaft portion 415 and engages with the engagement portion 312 of the cap 3. For example, the engagement portion 414 is provided radially between the shaft portion 415 and the seal portion 42. This will be described in detail later.

[0027] The shaft portion 415 is connected to the radial center of the ceiling portion 411 and extends from the ceiling portion 411 along the axis A1 toward the back side, i.e., the side of the base member 5. The shaft portion 415 is inserted into a through-hole 521 formed in the ceiling portion 52 of the base member 5 and prevents the valve member 4 from coming off the base member 5. In other words, the shaft portion 415 is a portion that prevents the valve member 4 from coming off the base member 5. This will be described in detail later.

[0028] 4, the shaft portion 415 has an engaging portion 416. The engaging portion 416 is provided at the tip of the shaft portion 415 in the extension direction, and extends radially outward from the outer circumferential surface of the shaft portion 415. The engaging portion 416 engages with the engaging portion 811 of the locking member 8.

[0029] As shown in FIG. 2, the protrusion 421 protrudes from the front surface of the flange portion 413 toward the front side. The protrusion 421 of this embodiment is an example of the "biasing portion" of the present invention. The protrusion 421 is provided between the engagement portion 414 and the seal portion 42 in the radial direction. As shown in FIG. 4, the protrusion 421 is interposed between the front surface of the flange portion 413 and the back surface of the cap 3, and biases the cap 3 toward the front side, i.e., in a direction away from the valve member 4.

[0030] The cap 3 has a ceiling portion 31, a peripheral wall portion 32, and a flange portion 33. The ceiling portion 31 has a disk shape and is provided in the radial center of the cap 3. The ceiling portion 31 has a through hole 311. The through hole 311 is formed near the outer peripheral edge of the ceiling portion 31, extending in the circumferential direction, and penetrates the ceiling portion 31 in the plate thickness direction (i.e., the direction of the axis A1). An engagement portion 312 is provided at the edge of the through hole 311. The engagement portion 312 of this embodiment is an example of a "second engagement portion" of the present invention.

[0031] 3, the engaging portion 312 protrudes from the edge of the through-hole 311 toward the inside of the through-hole 311, and engages with an engaging portion 414 provided on the ceiling portion 411 of the valve member 4. That is, the engaging portion 414 of the valve member 4 is inserted into the through-hole 311 of the cap 3, and the cap 3 rotates around the shaft portion 415 (i.e., around the axis A1) in the first direction A11 (see FIG. 1), whereby the engaging portion 312 of the cap 3 engages with the engaging portion 414 of the valve member 4. This will be described in detail later. In this way, the cap 3 is attached to the valve member 4 and covers the valve member 4.

[0032] The peripheral wall portion 32 is connected to the outer peripheral edge of the ceiling portion 31 and extends from the outer peripheral edge of the ceiling portion 31 toward the back side, i.e., the side of the valve member 4. The flange portion 33 is connected to the tip of the peripheral wall portion 32 in the extension direction and extends radially outward from the tip of the peripheral wall portion 32 in the extension direction. As shown in FIGS. 3 and 4 , when the cap 3 is attached to the valve member 4, the flange portion 33 covers the seal portion 42 of the valve member 4 and the valve seat 511 of the base member 5. This allows the cap 3 to prevent water sprayed from, for example, a high-pressure washer from directly hitting the seal portion 42 of the valve member 4.

[0033] The seal ring 6 is a so-called "O-ring" and is made of an elastic material such as rubber and has a circular ring shape. As shown in Figures 3 and 4, the seal ring 6 is attached to an annular protrusion 514 formed on the back side of the valve seat 511 of the base member 5. The seal ring 6 is interposed between the base member 5 and the case 9, and biases the base member 5 toward the front side.

[0034] The biasing member 7 is a coil spring formed by, for example, winding a wire rod of a predetermined diameter at a predetermined pitch. As shown in Figures 3 and 4, the biasing member 7 is disposed radially outside the shaft portion 415 of the valve member 4 and is supported by the shaft portion 415.

[0035] The locking member 8 has a tubular portion 81 and a flange portion 82. The tubular portion 81 has a substantially cylindrical shape and is provided in the radial center of the locking member 8. The tubular portion 81 has an engagement portion 811. The engagement portion 811 is provided inside the tubular portion 81 and extends radially inward from the inner circumferential surface of the tubular portion 81. The engagement portion 811 engages with an engagement portion 416 provided on the shaft portion 415 of the valve member 4 when the locking member 8 rotates in the second direction A12 (see FIG. 1). As a result, the locking member 8 is attached to the tip of the shaft portion 415 of the valve member 4, as shown in FIG. 4.

[0036] The flange portion 82 is connected to the tip of the cylindrical portion 81 in the direction of the axis A1, and extends radially outward from the tip of the cylindrical portion 81. As shown in FIGS. 3 and 4, the flange portion 82 sandwiches the urging member 7 together with the ceiling portion 52 of the base member 5. In other words, the urging member 7 is sandwiched in a contracted state between the flange portion 82 of the locking member 8 and the ceiling portion 52 of the base member 5.

[0037] As a result, the locking member 8 is biased in the direction of arrow A18 shown in FIGS. 3 and 4, i.e., toward the rear side. Because the locking member 8 is attached to the tip of the shaft portion 415 of the valve member 4, the valve member 4 is biased by the biasing member 7 via the locking member 8 in the direction of arrow A18 shown in FIGS. 3 and 4, i.e., toward the rear side. Therefore, when the pressure inside the case 9 is normal, the seal portion 42 contacts the valve seat 511 of the base member 5 and closes the vent hole 512. This seals the internal space S1 of the case 9. Furthermore, as shown in FIGS. 3 and 4, when the seal portion 42 contacts the valve seat 511 of the base member 5 and closes the vent hole 512, the flange portion 33 of the cap 3 covers the seal portion 42 of the valve member 4 and the valve seat 511 of the base member 5.

[0038] When the pressure in the internal space S1 of the case 9 increases, the valve member 4 receives a force toward the front side from the gas inside the case 9 through the vent hole 512. When the pressure in the internal space S1 of the case 9 increases above a predetermined value, the valve member 4, cap 3, and locking member 8 move integrally toward the front side while resisting the biasing force of the biasing member 7. As a result, the gas in the internal space S1 of the case 9 passes through the vent hole 512, passes through the gap formed between the seal portion 42 of the valve member 4 and the valve seat 511 of the base member 5, and passes through the gap formed between the flange portion 33 of the cap 3 and the annular portion 51 of the base member 5, and is released into the external space S2 of the case 9.

[0039] At this time, the maximum movement position (full stroke position) of the valve member 4, cap 3, and locking member 8 is determined by the flange portion 82 of the locking member 8 abutting against the rib 53 of the base member 5. In other words, the locking member 8 attached to the shaft portion 415 of the valve member 4, together with the rib 53 of the base member 5, determines the maximum movement position of the valve member 4, cap 3, and locking member 8. In this way, the shaft portion 415 of the valve member 4 and the locking member 8 prevent the valve member 4 from coming off the base member 5. In other words, the shaft portion 415 of the valve member 4 and the locking member 8 function as a retaining portion for preventing the valve member 4 from coming off the base member 5.

[0040] FIG. 5 is a cross-sectional view showing a pressure release valve according to a modified example of this embodiment. FIG. 5 corresponds to a cross-sectional view taken along the line AA in FIG. In addition, in cases where the components of the pressure release valve 2A of this modified example are similar to the components of the pressure release valve 2 of this embodiment described above with reference to Figures 1 to 4, duplicate explanations will be omitted as appropriate, and the following explanation will focus on the differences.

[0041] The valve member 4A of the pressure release valve 2A according to this modification has a base portion 41A and a seal portion 42. The base portion 41A has an engagement portion 416. The engagement portion 416 of this modification is an example of the "first engagement portion" of the present invention. The engagement portion 416 is provided on the outer peripheral surface of the peripheral wall portion 412 of the base portion 41A. In this respect, the valve member 4A of this modification differs from the valve member 4 of the present embodiment described above with reference to FIGS. 1 to 4. The engagement portion 416 protrudes radially outward from the outer peripheral surface of the peripheral wall portion 412 and extends circumferentially along the outer peripheral surface of the peripheral wall portion 412.

[0042] The cap 3A has a ceiling portion 31, a peripheral wall portion 32A, and a flange portion 33. The peripheral wall portion 32A has a through hole 321. The through hole 321 is formed in the circumferential direction along the outer circumferential surface of the peripheral wall portion 32A and penetrates the peripheral wall portion 32A in the thickness direction (i.e., the radial direction). An engagement portion 322 is provided on the edge of the through hole 321. In this respect, the cap 3A of this modified example differs from the cap 3 of the present embodiment described above with reference to FIGS. 1 to 4. The engagement portion 322 of this modified example is an example of the "second engagement portion" of the present invention.

[0043] The engaging portion 322 protrudes from the edge of the through-hole 321 toward the inside of the through-hole 321 and engages with an engaging portion 416 provided on the peripheral wall portion 412 of the valve member 4A. That is, the engaging portion 416 of the valve member 4A is inserted into the through-hole 321 of the cap 3A, and the cap 3A rotates around the shaft portion 415 (i.e., around the axis A1) in the first direction A11 (see FIG. 1), whereby the engaging portion 322 of the cap 3A engages with the engaging portion 416 of the valve member 4A. In this way, the cap 3A is attached to the valve member 4A and covers the valve member 4A. The other structures are the same as those of the pressure release valve 2 according to this embodiment described above with reference to FIGS.

[0044] Next, the valve member 4 and the cap 3 of this embodiment will be further described with reference to the drawings. FIG. 6 is a perspective view showing the valve member of this embodiment.

[0045] 1 to 4, the engaging portion 414 is provided on the front surface of the ceiling portion 411, and is formed to extend in the circumferential direction near the outer periphery of the ceiling portion 411. The engaging portion 414 is provided radially outward of the shaft portion 415, and has a first wall portion 414a, a second wall portion 414b, and a third wall portion 414c.

[0046] The first wall portion 414a protrudes from the front surface of the ceiling portion 411 toward the front side, and extends in the circumferential direction along the outer periphery of the ceiling portion 411.

[0047] The second wall portion 414b is connected to an end portion of the first wall portion 414a in the first direction A11 and, like the first wall portion 414a, protrudes toward the front side from the front surface of the ceiling portion 411. The height that the second wall portion 414b protrudes from the front surface of the ceiling portion 411 is the same as the height that the first wall portion 414a protrudes from the front surface of the ceiling portion 411. The second wall portion 414b extends radially outward from the end portion of the first wall portion 414a in the first direction A11.

[0048] The third wall portion 414c is connected to the front end portion of the first wall portion 414a and the front end portion of the second wall portion 414b, and similar to the first wall portion 414a, extends in the circumferential direction along the outer circumferential edge of the ceiling portion 411. As shown in FIG. 6, the third wall portion 414c functions as the ceiling portion of the engagement portion 414.

[0049] The third wall portion 414c has a protrusion 414d. The protrusion 414d is provided at an end of the third wall portion 414c in the second direction A12 and protrudes from the rear surface of the third wall portion 414c toward the rear side, i.e., from the rear surface of the third wall portion 414c toward the ceiling portion 411. As shown in Fig. 6, the end of the engagement portion 414 in the second direction A12 does not have a wall portion (the second wall portion 414b in the example shown in Fig. 6) like the end of the engagement portion 414 in the first direction A11, but rather opens as an opening.

[0050] 6 has four engagement portions 414. However, the number of engagement portions 414 is not limited to four, and may be, for example, three, five or more.

[0051] FIG. 7 is a perspective view showing the cap of this embodiment. As described above with reference to FIGS. 1 to 4, the engaging portion 312 protrudes from the edge of the through hole 311 toward the inside of the through hole 311. Specifically, the engaging portion 312 is formed on the first hole edge 311a of the through hole 311, and protrudes from the first hole edge 311a toward the inside of the through hole 311. The first hole edge 311a is an edge portion on the outer circumferential side of the through hole 311 that is formed to extend in the circumferential direction. The engaging portion 312 extends in the circumferential direction along the first hole edge 311a of the through hole 311. Furthermore, the engaging portion 312 has a thickness that allows it to fit into the engaging portion 414 of the valve member 4. This will be described in detail later.

[0052] 7, the engaging portion 312 is spaced apart from the second hole edge 311b of the through hole 311 in the circumferential direction. In other words, a gap 311c exists between the engaging portion 312 and the second hole edge 311b of the through hole 311. The second hole edge 311b of the through hole 311 is an edge portion of the through hole 311 that is located closer to the second direction A12 than the first hole edge 311a, and is formed to extend in the radial direction. As will be described later, a protrusion 414d of the engaging portion 414 of the valve member 4 fits into the gap 311c.

[0053] Note that the engaging portion 312 does not necessarily have to be spaced apart from the second hole edge 311b in the circumferential direction, as long as a groove or space is provided in which the protrusion 414d of the engaging portion 414 of the valve member 4 fits. For example, the engaging portion 312 may be connected to the second hole edge 311b, and a recess into which the protrusion 414d of the engaging portion 414 of the valve member 4 can fit may be provided at the connection portion between the engaging portion 312 and the second hole edge 311b.

[0054] 7 has four engaging portions 312. However, the number of engaging portions 312 is not limited to four, and may be, for example, three or five or more.

[0055] Next, the operation when the engaging portion 312 of the cap 3 and the engaging portion 414 of the valve member 4 engage with each other will be described with reference to the drawings. FIG. 8 is a perspective view showing the state before the cap of this embodiment is placed on the valve member. FIG. 9 is a perspective view showing the state before the engaging portion of the cap and the engaging portion of the valve member are engaged with each other. FIG. 10 is a cross-sectional view taken along the cutting plane CC shown in FIG. FIG. 11 is a cross-sectional view taken along the cutting plane DD shown in FIG. FIG. 12 is a perspective view showing the state after the engaging portion of the cap and the engaging portion of the valve member have engaged with each other. FIG. 13 is a cross-sectional view taken along the cutting plane EE shown in FIG. FIG. 14 is a cross-sectional view taken along the cutting plane FF shown in FIG.

[0056] First, as indicated by arrow A13 in Fig. 8, the cap 3 is placed on the valve member 4 in a state where the seal portion 42 of the valve member 4 is in contact with the valve seat 511 of the base member 5 to close the vent hole 512. At this time, the position of the through-hole 311 of the cap 3 is aligned with the position of the engagement portion 414 of the valve member 4.

[0057] 9, the engaging portion 414 of the valve member 4 is inserted into the through-hole 311 of the cap 3. In this state, as shown in FIG. 11, the flange portion 33 of the cap 3 covers the seal portion 42 of the valve member 4 and the valve seat 511 of the base member 5. Also, as shown in FIGS. 10 and 11, the engaging portion 414 of the valve member 4 is located on the first direction A11 side of the engaging portion 312 of the cap 3 inside the through-hole 311. In other words, the engaging portion 312 of the cap 3 is not yet engaged with the engaging portion 414 of the valve member 4.

[0058] Subsequently, when the cap 3 rotates in the first direction A11 around the axis A1, the engaging portion 312 of the cap 3 moves in the first direction A11 around the axis A1 and approaches the engaging portion 414 of the valve member 4. In other words, the engaging portion 414 of the valve member 4 moves in the second direction A12 around the axis A1 inside the through-hole 311 relative to the cap 3 and approaches the engaging portion 312 of the cap 3.

[0059] 11, the distance between the front surface of the ceiling portion 411 and the back surface of the third wall portion 414c in the direction of the axis A1 is longer than the thickness of the engaging portion 312 of the cap 3. In addition, the distance between the front surface of the ceiling portion 411 and the back end of the protrusion portion 414d in the direction of the axis A1 is the same as the thickness of the engaging portion 312 of the cap 3 or slightly shorter than the thickness of the engaging portion 312 of the cap 3.

[0060] Therefore, as the end of the third wall portion 414c on which the protrusion 414d is provided bends toward the front side along the direction of the axis A1, the engaging portion 312 of the cap 3 passes between the front surface of the ceiling portion 411 and the rear end of the protrusion 414d. In other words, as the end of the third wall portion 414c on which the protrusion 414d is provided bends toward the front side along the direction of the axis A1, the protrusion 414d climbs over the engaging portion 312 from the end side of the engaging portion 312 in the first direction A11 and moves toward the end side of the engaging portion 312 in the second direction A12.

[0061] Next, when the cap 3 is further rotated in the first direction A11 around the axis A1, as shown in FIGS. 12 to 14, the engaging portion 312 of the cap 3 fits between the front surface of the ceiling portion 411 and the back surface of the third wall portion 414c. Also, as shown in FIG. 14, the protrusion 414d of the engaging portion 414 of the valve member 4 fits into the gap 311c formed between the engaging portion 312 of the cap 3 and the second hole edge 311b of the through-hole 311. In this way, as shown in FIGS. 12 to 14, the engaging portion 312 of the cap 3 engages with the engaging portion 414 of the valve member 4.

[0062] 13 and 14, when the engaging portion 312 of the cap 3 engages with the engaging portion 414 of the valve member 4, the second hole edge 311b of the through hole 311 abuts against the end of the engaging portion 414 of the valve member 4 in the second direction A12. As a result, the second hole edge 311b of the through hole 311 restricts the cap 3 from further rotating in the first direction A11 around the axis A1.

[0063] On the other hand, as shown in Figures 13 and 14, when the engagement portion 312 of the cap 3 engages with the engagement portion 414 of the valve member 4, the inner surface of the second wall portion 414b (i.e., the inner surface facing the second direction A12) is spaced apart from the engagement portion 312 of the cap 3 in the circumferential direction.

[0064] 13, when the engaging portion 312 of the cap 3 is engaged with the engaging portion 414 of the valve member 4, the inner surface of the second wall portion 414e may abut against the engaging portion 312 of the cap 3. In this embodiment, the second wall portion 414e shown by the dashed double-dashed line is an example of the "stopper portion" of the present invention provided at the end of the engaging portion 414 of the valve member 4 in the first direction A11.

[0065] As described above, in the pressure release valve 2 according to this embodiment, the engaging portion 414 of the valve member 4 is provided radially outward of the shaft portion 415 of the valve member 4. The engaging portion 312 of the cap 3 engages with the engaging portion 414 of the valve member 4 by rotating in the first direction A11 around the shaft portion 415. In this way, the cap 3 having the engaging portion 312 engages with the valve member 4 having the engaging portion 414 by rotating in the first direction A11 around the shaft portion 415 of the valve member 4. As a result, the height of the pressure release valve 2 according to this embodiment in the direction of the axis A1 can be kept low compared to when the cap 3 is attached to the valve member 4 along the axis A1.

[0066] Furthermore, the second hole edge 311b of the through hole 311, which is located closer to the second direction A12 than the first hole edge 311a of the through hole 311, where the engagement portion 312 of the cap 3 is formed, abuts against the engagement portion 414 of the valve member 4, thereby restricting the rotation of the cap 3 in the first direction A11. Therefore, the pressure release valve 2 according to this embodiment can restrict the rotation of the cap 3 in the first direction A11 inside the through hole 311 of the cap 3. This allows the height of the pressure release valve 2 according to this embodiment in the direction of the axis A1 to be kept even lower.

[0067] 13, the second wall portion 414e comes into contact with the engaging portion 312 formed on the first hole edge 311a of the through hole 311 of the cap 3, and functions as a stopper. Therefore, in this case, the pressure release valve 2 according to this embodiment can restrict the rotation of the cap 3 in the first direction A11 inside the through hole 311 of the cap 3. This allows the pressure release valve 2 according to this embodiment to have an even lower height in the direction of the axis A1.

[0068] Furthermore, the engaging portion 414 of the valve member 4 moves in the second direction A12 inside the through hole 311 of the cap 3 relative to the cap 3 and engages with the engaging portion 312 of the cap 3. Therefore, the engaging portion 414 of the valve member 4 can guide the rotation of the engaging portion 312 formed on the first hole edge 311a of the through hole 311 of the cap 3. This improves the efficiency of the work of attaching the cap 3 to the valve member 4.

[0069] Furthermore, the protrusion 421 of the valve member 4 is provided between the engagement portion 414 of the valve member 4 and the seal portion 42 of the valve member 4 in the radial direction, and urges the cap 3 in a direction away from the valve member 4. Therefore, the protrusion 421 of the valve member 4 can urge the cap 3 in a direction away from the valve member 4 in the vicinity of the engagement portion 414 of the valve member 4 and the engagement portion 312 of the cap 3. This makes it possible to suppress vibration of the cap 3 relative to the valve member 4 when the engagement portion 312 of the cap 3 is engaged with the engagement portion 414 of the valve member 4.

[0070] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiments can be partially omitted or arbitrarily combined in a different manner from the above. [Explanation of symbols]

[0071] 2: Pressure release valve, 2A: Pressure release valve, 3: Cap, 3A: Cap, 4: Valve member, 4A: Valve member, 5: Base member, 6: Seal ring, 7: Biasing member, 8: Lock member, 9: Case, 31: Ceiling portion, 32: Circumferential wall portion, 32A: Circumferential wall portion, 33: Flange portion, 41: Base portion, 41A: Base portion, 42: Seal portion, 51: Annular portion, 52: Ceiling portion, 53: Rib, 54: Insertion portion, 81: Cylindrical portion, 82: Flange portion, 91: Opening, 92: Edge portion, 311: Through hole, 311a: First hole edge, 311b: Second hole edge, 311c: Gap, 312: Engagement portion, 321: Through hole, 322: Engagement portion, 411: Ceiling portion, 412: Peripheral wall portion, 413: Flange portion, 414: Engagement portion, 414a: First wall portion, 414b: Second wall portion, 414c: Third wall portion, 414d: Protrusion portion, 414e: Second wall portion, 415: Shaft portion, 416: Engagement portion, 421: Protrusion portion, 511: Valve seat, 512: Vent hole, 513: Inner peripheral surface, 514: Protrusion portion, 521: Through hole, 811: Engagement portion, 921: Inner peripheral surface, 922: Flange portion

Claims

1. a base member that is inserted into an opening formed in the case and fixed to an edge of the opening, the base member having a vent hole that connects an internal space of the case with an external space of the case, and the base member having a valve seat; a valve member having a shaft portion that prevents the valve member from coming off the base member, a seal portion that comes into contact with and separates from the valve seat to open and close the vent hole, and a first engagement portion that is provided radially outward of the shaft portion; a cap having a second engaging portion that covers the valve seat and the sealing portion when the sealing portion is in contact with the valve seat to close the vent hole, and that engages with the first engaging portion by rotating in a first direction around the shaft portion; A pressure relief valve comprising:

2. The cap has a through hole that penetrates the cap in a plate thickness direction, the second engaging portion is formed on a first hole edge of the through hole, 2. The pressure release valve according to claim 1, wherein a second hole edge of the through hole, which is located on the second direction side opposite the first direction from the first hole edge, abuts against the first engagement portion to restrict rotation of the cap in the first direction.

3. 3. The pressure release valve according to claim 2, wherein the first engaging portion has a stopper portion provided at an end in the first direction and abutting against the second engaging portion.

4. 3. The pressure release valve according to claim 2, wherein the first engaging portion moves in the second direction inside the through hole relative to the cap as the cap rotates in the first direction, and engages with the second engaging portion.

5. 2. The pressure release valve according to claim 1, wherein the valve member has a biasing portion disposed between the first engaging portion and the sealing portion in the radial direction and biasing the cap in a direction away from the base member.

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