ventilation component

Abstract

Ventilation component (1) to be attached to a housing (2) at a ventilation opening (5) of the housing (2), comprising: a gas-permeable membrane (10); a ventilation valve (20) comprising an elastic body and which is opened and closed by elastic deformation of the elastic body; and a structural element (30) that supports the gas-permeable membrane (10) and the ventilation valve (20), wherein in an installed state in which the ventilation component (1) is attached to the housing (2), ventilation is carried out between an inside of the housing (2) and an outside of the housing (2) by means of the gas-permeable membrane (10) and the ventilation valve (20) is opened to release a gas inside the housing (2) to the outside of the housing (2) when a difference between a pressure inside the housing (2) and a pressure outside the housing (2) is equal to or greater than a predetermined value, and the elastic body is made of a rubber whose rate of change of tensile strength, as determined by the formula (1) below, is 95% to 120%: Rate of change of tensile strength = 100 × first tensile strength / second tensile strength wherein the first tensile strength is a tensile strength determined when a test specimen made of the rubber, having a thickness of 2.0 mm and stamped into a No. 3 dumbbell shape, is heated according to the heat resistance test, method A, according to the Japanese Industrial Standard (JIS) K 6257:2010 and then subjected to a tensile test at a tensile speed of 500 mm / minute, and The second tensile strength is a tensile strength that is determined when the test specimen is subjected to a tensile test at a tensile speed of 500 mm / minute without being heated in accordance with the heat resistance test, procedure A. where the second tensile strength of the rubber is 5 to 10 MPa.

Description

TECHNICAL AREA

[0001] The present invention relates to a ventilation component. STATE OF THE ART

[0002] Traditionally, devices are known for compensating for a difference between a pressure inside a housing and a pressure outside the housing.

[0003] For example, patent document 1 describes a pressure compensation device that can be used for an enclosure where an undesirable difference between the pressure inside the enclosure and the pressure outside the enclosure should be avoided. This pressure compensation device has an inner and an outer surface and comprises a cage, a gas-permeable membrane, and a pressure relief valve. The cage comprises an inner half and an outer half. Inside the cage, the gas-permeable membrane and the pressure relief valve are arranged between the inner and outer halves. The pressure relief valve provides explosion protection.If the pressure on the inside is higher than the pressure on the outside, and the difference between them exceeds a threshold, a flow path is formed that allows the inside to be directly connected to the outside, so that any gas on the inside is immediately vented. The gas-permeable membrane does not contribute to explosion protection. The pressure relief valve has an outer circumferential section that seals a cage sealing surface using pressure derived from elasticity. For example, patent document 2 describes a rubber-elastic overpressure relief valve that safely vents excess internal pressure from sealed containers of a closed system, such as fuel cells, electrolysis tanks of secondary cells, reaction vessels, storage tanks, etc., or sealed piping systems, to the outside world, and a relief valve assembly with such a valve.For example, patent document 3 describes a check valve structure provided in a fluid flow path. DOCUMENT LISTPatent documents Patent document 1: DE 10 2017 003 360 B3 Patent document 2: EP 2 131 416 A1 Patent document 3: JP 2016 - 56 902 A SUMMARY OF THE INVENTION Technical Problem

[0004] Patent document 1 does not include detailed investigations regarding the material of an elastic body forming the pressure relief valve, and consequently, the technology described in patent document 1 offers room for improvement with regard to increasing the heat resistance of the pressure relief valve. Therefore, the present invention provides a venting component suitable for explosion protection and comprising a venting valve that is advantageous with respect to heat resistance. Solution to the problem

[0005] The present invention provides a ventilation component to be attached to a housing at a ventilation opening of the housing, comprising: a gas-permeable membrane; a ventilation valve comprising an elastic body and which is opened and closed by elastic deformation of the elastic body; and a structural element that supports the gas-permeable membrane and the ventilation valve, wherein in an installed state, where the ventilation component is attached to the housing, ventilation is carried out between an inside of the housing and an outside of the housing by means of the gas-permeable membrane, and the ventilation valve is opened to release gas from inside the housing to the outside of the housing when a difference between a pressure inside the housing and a pressure outside the housing is equal to or greater than a predetermined value, and the elastic body is made of a rubber whose rate of change of tensile strength, as determined by the formula (1) below, is 95% to 120%: Rate of change in tensile strength = 100 × first tensile strength / second tensile strength wherein the first tensile strength is a tensile strength determined when a test specimen made of the rubber, having a thickness of 2.0 mm and stamped into a No. 3 dumbbell shape, is heated according to the heat resistance test, method A, according to the Japanese Industrial Standard (JIS) K 6257:2010 and then subjected to a tensile test at a tensile speed of 500 mm / minute, and The second tensile strength is a tensile strength that is determined when the test specimen is subjected to a tensile test at a tensile speed of 500 mm / minute without being heated in accordance with the heat resistance test, procedure A. where the second tensile strength of the rubber is 5 to 10 MPa. Advantageous effects of the invention

[0006] The aforementioned ventilation component is suitable for ventilation aimed at explosion protection and includes a ventilation valve which is advantageous with regard to heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a view from below showing an example of a ventilation component of the present invention. Fig. Figure 2 is a cross-sectional view of the ventilation component, which is located in the Fig. 1 is shown, along line II-II. Fig. Figure 3 is a perspective view showing a ventilation opening of a housing. Fig. Figure 4 is a cross-sectional view showing a state where the ventilation component is attached to the housing. Fig. Figure 5 is a cross-sectional view showing a state where a ventilation valve is open. Fig. 6A is a top view of the ventilation valve. Fig. 6B is a top view of the ventilation valve. Fig. Figure 7 is a partially enlarged cross-sectional view of the ventilation component, which is located in the Fig. 1 is shown. DESCRIPTION OF EXECUTION FORMS

[0007] For example, the housing of an electrical component in a vehicle must have ventilation properties to eliminate pressure differentials that occur inside due to temperature changes. At the same time, the required level of ventilation can vary depending on phenomena occurring within the housing. For instance, preventing a battery pack from exploding requires the rapid release of a large amount of gas from inside the housing. In such cases, it is conceivable to install a ventilation component, comprising a gas-permeable membrane and a vent valve, at a ventilation opening in the housing.In this case, regular ventilation occurs via the gas-permeable membrane when the vent valve is closed. Conversely, if the pressure difference between the inside and outside of the housing increases to a predetermined value or higher, the vent valve opens, allowing a large quantity of gas to be released from the inside of the housing in a short time. The vent valve can be reused by employing a type of vent valve that is opened and closed by the elastic deformation of an elastic body within it.

[0008] In the pressure compensation device described in patent document 1, it is proposed to construct an outer circumferential section of the pressure relief valve from an elastically deformable material. However, according to patent document 1, no detailed investigations are carried out regarding the heat resistance of the pressure relief valve material. The present inventors have found that a venting component and a product to which the venting component is attached may be used in a high-temperature environment, and it is therefore extremely important to increase the heat resistance of the venting valve. With this in mind, the present inventors have conducted intensive investigations into techniques for increasing the heat resistance of the venting valve.As a result, the present inventors have discovered for the first time that, with regard to increasing the heat resistance of the ventilation valve, it is advantageous to form an elastic body incorporated into the ventilation valve from a rubber that fulfills a predetermined relationship with respect to tensile strength, and have thus invented a ventilation component of the present invention. It should be noted that a housing to which the ventilation component of the present invention is to be attached is not limited to a housing of an electrical component of a vehicle.

[0009] Embodiments of the present invention are described below with reference to the accompanying drawings. The following description provides examples of the present invention, and the present invention is not limited to the following embodiments.

[0010] As it is in the Fig. 1 and the Fig. As shown in Figure 2, a ventilation component 1 comprises a gas-permeable membrane 10, a ventilation valve 20, and a structural element 30. The ventilation component 1 is a component to be attached to a housing 2 with a ventilation opening 5, as shown in the Fig. 3 is shown. As it is in the Fig. As shown in Figure 4, the ventilation component 1 is to be attached to the housing 2 at the ventilation opening 5. As shown in the Fig. 4 and the Fig.As shown in Figure 5, the ventilation valve 20 comprises an elastic body and is opened and closed by elastic deformation of the elastic body. The structural element 30 supports the gas-permeable membrane 10 and the ventilation valve 20. In an installed state, with the ventilation component 1 attached to the housing 2, ventilation occurs between an inner and an outer surface of the housing 2 via the gas-permeable membrane 10. Furthermore, in the installed state, the ventilation valve 20 opens, allowing gas inside the housing 2 to escape to the outer surface when the pressure difference between the pressure inside the housing 2 and the pressure outside the housing 2 is equal to or greater than a predetermined value.In other words, when the difference between the pressure inside housing 2 and the pressure outside housing 2 is less than the specified value, the vent valve 20 is closed. The elastic body incorporated into the vent valve 20 is made of a rubber whose rate of change of tensile strength, as defined by formula (1) below, is 95% to 120%. In this description, this rubber is referred to as "heat-resistant rubber." In formula (1), the first tensile strength is determined when a test specimen made of the rubber, with a thickness of 2.0 mm and stamped into a No. 3 dumbbell shape, is heated according to the heat resistance test, method A, specified in JIS K 6257:2010, and then subjected to a tensile test at a tensile rate of 500 mm / minute.Furthermore, the second tensile strength is a tensile strength that is determined when the aforementioned test specimen is subjected to a tensile test at a tensile speed of 500 mm / minute without being heated in accordance with the aforementioned heat resistance test, Method A. Rate of change in tensile strength = 100 × first tensile strength / second tensile strength

[0011] Since the elastic body incorporated into the vent valve 20 is made of heat-resistant rubber, it is unlikely that the tensile strength of the heat-resistant rubber from which the elastic body of the vent valve 20 is formed will vary, even when the vent valve 20 is used in a high-temperature environment. In this case, it is assumed that the pressure required to open the vent valve 20 is unlikely to vary and that it is likely to fall within a desired range during the period in which the vent component 1 is used. This is advantageous for improving the reliability of the vent component 1 and of a product to which the vent component 1 is attached.

[0012] Typically, the values ​​of the first tensile strength and the second tensile strength of the heat-resistant rubber from which the elastic body in the ventilation component 1 is formed are values ​​at the time of shipment of the ventilation component 1. For example, the aforementioned test specimen is manufactured using a material identical to a material of the heat-resistant rubber from which the elastic body in the ventilation component 1 is formed, according to conditions for forming the elastic body that is incorporated into the ventilation valve 20.

[0013] The heat-resistant rubber is not limited to a specific type of rubber, as long as the aforementioned rate of change in tensile strength is between 95% and 120%. The heat-resistant rubber can be ACM, AEM, ANM, CM, CSM, EBM, EOM, EPDM, EPM, EVM, FEPM, FFKM, FKM, IM, NBM, SEBM, SEPM, CO, ECO, GCO, GECO, GPO, FMQ, FVMQ, MQ, PMQ, PVMQ, VMQ, ABR, BR, CR, CR, ENR, HNBR, IIR, IR, MSBR, NBIR, NBR, NIR, NR, NOR, PBR, PSBR, SBR, E-SBR, S-SBR, SIBR, XBR, XCR, XNBR, XSBR, BIIR, CIIR, OT, EOT, AFMU, AU, EU, FZ, or PZ. These abbreviations are used in accordance with JIS K 6397:2005.

[0014] The second tensile strength of the heat-resistant rubber from which the elastic body in the ventilation component 1 is formed is 5 to 10 MPa. This makes it likely that the pressure for opening the ventilation valve 20 will more reliably fall within a desired range during the service life of the ventilation component 1. The second tensile strength of the heat-resistant rubber from which the elastic body in the ventilation component 1 is formed is preferably 6 to 9 MPa, and more preferably 7 to 8 MPa.

[0015] For HIS-30, HIS-35, HIS-40, HIS-45, HIS-50, HIS-55, and HIS-60, the initial tensile strength, the second tensile strength, and the rate of change of tensile strength were calculated. Table 1 shows the results. These are silicone rubbers. As shown in Table 1, HIS-30, HIS-40, HIS-45, HIS-50, HIS-55, and HIS-60 can be used as heat-resistant rubbers. [Table 1] Type of rubber First tensile strength (with heat resistance test) [MPa] Second tensile strength (without heat resistance test) [MPa] Rate of change of tensile strength [%] HIS-30 7,6 7,8 97 HIS-35 7,0 7,7 91 HIS-40 8,2 7,5 109 HIS-45 7,7 7,7 100 HIS-50 8,6 7,6 113 HIS-55 7,3 7,4 99 HIS-60 7,2 7,2 100

[0016] As it is in the Fig. As shown in Figure 2, the ventilation valve 20 comprises an approximately plate-like structural section with two surfaces 20f and 20s pointing in opposite directions. The structural section is formed from the elastic body, and the elastic body is formed from the heat-resistant rubber. Furthermore, the structural section has, for example, a minimum thickness of 2.0 mm to 4.0 mm. The heat-resistant rubber has a durometer hardness, as specified in JIS K 6253-3:2012, of A 30 to 80.

[0017] As it is in the Fig. 6A and the Fig.As shown in Figure 6B, the ventilation valve 20 is a type of so-called umbrella valve (a drain valve of the umbrella type) and has a ring shape, which, for example, has an inner circumferential section 21 and an outer circumferential section 22 when one of the two surfaces 20f and 20s is viewed in the plane. The ventilation valve 20 has a through-hole 25 at its center. The inner circumferential section 21 adjoins the through-hole 25. Furthermore, as shown in the Fig. As shown in Figure 2, the structural element 30 comprises a support section 35 and a valve seat section 36. The support section 35 supports the inner circumferential section 21. As shown in the Fig. 4 and the Fig.As shown in Figure 5, the valve seat section 36 is in contact with the outer circumferential section 22 when the vent valve 20 is closed, and is not in contact with the outer circumferential section 22 when the vent valve is open. The umbrella valve typically comprises a valve section used for opening and closing, and a stem section that supports the valve section. There is also an umbrella valve that has one element forming the valve section and another, separate element forming the stem section. For example, the vent valve 20 forms only the valve section, and the valve section has an annular shape when viewed in the plane. The structural element 30 acts as the stem section that supports the vent valve 20, which is the valve section. The through-hole 25 of the vent valve 20 is used to support the vent valve 20 by means of the structural element 30.Furthermore, when the ventilation component 1 is viewed in the plane, the gas-permeable membrane 10 is positioned further inward than an inner circumferential surface that forms the through-hole 25 of the ventilation valve 20. As described here, the through-hole 25 of the ventilation valve 20 has a size sufficient to accommodate the gas-permeable membrane 10.

[0018] The vent valve 20 is not limited to a vent valve of a specific shape, as long as the vent valve 20 opens by its elastic deformation and closes by returning to the shape it had before the deformation. The vent valve 20 can be of a so-called duckbill valve type or it can be of a shield valve type. If the vent valve 20 is a shield valve, it can comprise the valve section and the stem section, or it can consist solely of the valve section. If the vent valve 20 is a shield valve composed solely of the valve section, it can have a through-hole or it can be without a through-hole.If the ventilation valve 20 is a shield valve with a through-hole, the through-hole has a shape that is not limited to a specific shape and the through-hole has dimensions that are not limited to specific values.

[0019] As it is in the Fig. 1 and the Fig. As shown in Figure 2, the structural element 30, for example, has an engagement section 32c. The engagement section 32c is to be inserted into the ventilation opening 5 of the housing 2. The ventilation component 1 also includes, for example, a sealing element 60. As shown in the Fig.As shown in Figure 4, the sealing element 60 seals a gap between the structural element 30 and an outer surface 2s of the housing 2, to which the ventilation component 1 is attached, in its installed state. This prevents a fluid from being directed through the gap between the structural element 30 and the outer surface 2s into the interior of the housing 2. The sealing element 60 is, for example, an O-ring or a sealing packing. Examples of materials for the sealing element 60 include an elastically deformable material.

[0020] One material of the sealing element 60 is an elastomer, such as natural rubber, synthetic rubber, and thermoplastic elastomer. In this case, examples of synthetic rubber include NBR, EPDM, silicone rubber, fluororubber, acrylic rubber, and hydrogenated nitrile rubber.

[0021] The gas-permeable membrane 10 is not limited to a specific membrane, as long as it exhibits the desired ventilation properties. The gas-permeable membrane 10 can be a single-layer membrane or a multi-layer membrane. If the gas-permeable membrane 10 is a multi-layer membrane, each layer can be selected from the group consisting of a porous membrane, a nonwoven fabric, a woven fabric, and a mesh. The gas-permeable membrane 10 can comprise: a porous membrane and a nonwoven fabric; at least one of a woven fabric and a mesh, and a porous membrane; or a plurality of nonwoven fabrics. Typically, the gas-permeable membrane 10 is composed of an organic polymer material (resin). Examples of a porous membrane material include a fluorinated resin.Examples of fluoropolymers used include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, a tetrafluoroethylene-hexafluoropropylene copolymer, or a tetrafluoroethylene-ethylene copolymer. Materials suitable for nonwovens, woven fabrics, and nets include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, nylon, aramid, and ethylene-vinyl acetate copolymers.

[0022] The gas-permeable membrane 10 can optionally be subjected to a liquid-repellent treatment. This treatment is carried out, for example, by forming a liquid-repellent coating film on the gas-permeable membrane 10, containing a fluorine-based surface modifier with a perfluoroalkyl group. The formation of the liquid-repellent coating film is not specifically limited and is achieved, for example, by coating a porous resin membrane with a solution or dispersion of the fluorine-based surface modifier with a perfluoroalkyl group using a process such as air spraying, electrostatic spraying, dip coating, centrifugal coating, roller coating, curtain coating, or impregnation.Alternatively, the liquid-repellent coating film can be formed by an electrodeposition process or a plasma polymerization process.

[0023] The vent valve 20 is opened by its elastic deformation and closed by returning to the shape it had before the deformation. This allows the vent valve 20 to be opened and closed repeatedly and reused. This has the advantage that a product in which the venting component 1 is attached to the housing 2 can be shipped after it has been inspected to see if the vent valve 20 is functioning correctly.

[0024] As it is in the Fig.As shown in Figure 7, the support section 35 has, for example, a first contact section 35f and a second contact section 35s. The first contact section 35f and the second contact section 35s surround the inner circumferential section 21 of the vent valve 20. The first contact section 35f is in contact with a surface 21q, which is one of a pair of surfaces 21p facing in opposite directions within the inner circumferential section 21. Furthermore, the second contact section 35s is in contact with a surface 21r, which is the other surface of the pair of surfaces 21p within the inner circumferential section 21. The support section 35 is in contact with an end surface 21e of the inner circumferential section 21, which connects the pair of surfaces 21p between the first contact section 35f and the second contact section 35s.The inner circumferential section 21 is surrounded by the first contact section 35f and the second contact section 35s and is also in contact with the support section 35 at the end surface 21e. This also improves the sealing capacity between the vent valve 20 and the support section 35. As a result, a liquid and a gas cannot pass through a gap between the support section 35 and the inner circumferential section 21, thus increasing the reliability of the venting component 1 and of a product to which the venting component 1 is attached.

[0025] For example, in a state where the elastic body of the vent valve 20 is pressed against the support section 35 by its elastic deformation, the end surface 21e of the inner circumferential section 21 is in contact with the support section 35. In this case, the sealing capacity between the vent valve 20 and the support section 35 is improved.

[0026] The inner circumferential section 21 is, for example, in liquid-tight contact with the support section 35 at the end surface 21e. Preferably, the inner circumferential section 21 is in liquid-tight and airtight contact with the support section 35 at the end surface 21e. In this case, the sealing performance between the vent valve 20 and the support section 35 is more likely to be improved. In this case, "airtight" means that a pressure difference of 10 kPa or more can be maintained between the two spaces separated by the end surface 21e.

[0027] The first contact section 35f and the second contact section 35s are in contact with the inner circumferential section 21 in a state in which the elastic body of the ventilation valve 20 is, for example, pressed against the inner circumferential section 21 such that it is elastically deformed. The first contact section 35f and the second contact section 35s are, for example, in a liquid-tight manner in contact with the inner circumferential section 21. Preferably, the first contact section 35f and the second contact section 35s are in both a liquid-tight and airtight manner in contact with the inner circumferential section 21. In this case, "airtight" means that a pressure difference between the respective two spaces separated by the first contact section 35f or the second contact section 35s can be maintained at 10 kPa or more.

[0028] As it is in the Fig.As shown in Figure 2, the surface 20f of the ventilation valve 20 is designed, for example, such that no step is created between a section of the ventilation valve 20 adjacent to the inner circumferential section 21 and the inner circumferential section 21. This likely increases the contact area between the inner circumferential section 21 and the support section 35.

[0029] As it is in the Fig.As shown in Figure 2, the surface 20s of the vent valve 20 is designed, for example, such that a step is formed between the section of the vent valve 20 adjacent to the inner circumferential section 21 and the inner circumferential section 21. This results in the inner circumferential section 21 having a thickness greater than that of the section of the vent valve 20 adjacent to the inner circumferential section 21. Consequently, the degree of deformation of the inner circumferential section 21 surrounded by the support section 35 is likely to increase, thus improving the sealing capacity between the vent valve 20 and the support section 35.

[0030] As it is in the Fig.As shown in Figure 2, the structural section of the vent valve 20 has a curved section between a section of the vent valve 20 adjacent to the outer circumferential section 22 and the outer circumferential section 22, and the curved section is bent towards an inner surface of the vent valve 20. This likely increases the contact area between the outer circumferential section 22 and the valve seat section 36 when the vent valve 20 is closed. As a result, the sealing capacity between the outer circumferential section 22 and the valve seat section 36 is increased when the vent valve 20 is closed.

[0031] As it is in the Fig.As shown in Figure 2, the structural element 30, for example, has a first element 31 and a second element 32. The first element 31 supports the gas-permeable membrane 10. The first element 31 comprises a base section 31b and a shaft section 31s. The base section 31b, for example, has a disc shape and supports the gas-permeable membrane 10. The base section 31b has a through-hole 31h at its center for ventilation. The base section 31b supports a circumferential section of the gas-permeable membrane 10 outside the through-hole 31h in a direction perpendicular to an axis of the base section 31b. The gas-permeable membrane 10 is attached to the base section 31b by a process such as thermal welding, ultrasonic welding, or bonding with an adhesive. The shaft section 31s projects from the center of the base section 31b in an axial direction along the base section 31b.The shaft section 31s is cylindrical and has a plurality (for example, three) of leg sections 31g at positions remote from the base section 31b in the axial direction of the base section 31b. The leg sections 31g are arranged, for example, such that they are spaced apart from each other at equal angles about the axis of the base section 31b. Each of the leg sections 31g has an engagement section 31c at one end, projecting in a direction perpendicular to the axis of the base section 31b. A gas enters and exits through an interior of the base section 31s or through a gap between the leg sections 31g and the through-hole 31h, thus providing ventilation.

[0032] The second element 32 forms a lower section and a side section of the structural element 30. The second element 32 is an annular element and comprises an inner circumferential section 32i, an outer circumferential section 32e, and a connecting section 32k. The inner circumferential section 32i is located at a center of the second element 32 and is cylindrical. The outer circumferential section 32e is located perpendicular to an axis of the inner circumferential section 32i and surrounds the inner circumferential section 32i. The outer circumferential section 32e is cylindrical. The outer circumferential section 32e forms the side section of the structural element 30. The connecting section 32k is positioned between the outer circumferential section 32e and the inner circumferential section 32i in a direction perpendicular to the axis of the inner circumferential section 32i and connects the outer circumferential section 32e to the inner circumferential section 32i.The inner circumferential section 32i and the connecting section 32k form the lower section of the structural element 30. The inner circumferential section 32i has a through-hole 32h at its center. The first element 31 is attached to the second element 32 at an end section of the inner circumferential section 32i in an axial direction. At one end section of the inner circumferential section 32i, the attachment hole 32h forms a tapered hole. Furthermore, the inner circumferential section 32i has an annular engagement surface 32f that adjoins the tapered hole and extends in a direction perpendicular to the axis of the inner circumferential section 32i.The shaft section 31s is inserted into the tapered hole of the mounting hole 32h, and consequently the engagement sections 31c are directed towards the engagement surface 32f, thus preventing the first element 31 from being located outside the mounting hole 32h. Furthermore, an end surface adjacent to the tapered hole of the inner circumferential section 32i is directed axially towards a lower surface of the base section 31b of the first element 31.

[0033] The support section 35 is formed, for example, by the lower surface of the base section 31b of the first element 31 and an outer surface of one end section of the inner circumferential section 32i in the axial direction of the inner circumferential section 32i.

[0034] The inner circumferential section 32i has an inner circumferential surface configured such that a plurality (for example, three) of steps extend from the engagement surface 32f to the other end section of the inner circumferential section 32i in the axial direction of the inner circumferential section 32i. For example, the inner circumferential surface of the inner circumferential section 32i has a first side surface 32p, a second side surface 32q, a third side surface 32r, a first connecting surface 32t, and a second connecting surface 32u. The first side surface 32p, the second side surface 32q, and the third side surface 32r extend in the axial direction of the inner circumferential section 32i. Furthermore, the first side surface 32p, the second side surface 32q, and the third side surface 32r have a first inner diameter, a second inner diameter, and a third inner diameter, respectively.The first inner diameter is smaller than the second inner diameter, and the second inner diameter is smaller than the third inner diameter. The first connecting surface 32t and the second connecting surface 32u extend in a direction perpendicular to the axis of the inner circumferential section 32i. The first connecting surface 32t connects the first side surface 32p to the second side surface 32q. The second connecting surface 32u connects the second side surface 32q to the third side surface 32r.

[0035] As it is in the Fig.As shown in Figure 1, the inner circumferential section 32i comprises, for example, a plurality (e.g., three) of engagement sections 32c. The engagement sections 32c project, for example, outwards in the axial direction of the other end section of the inner circumferential section 32i, perpendicular to the axis of the inner circumferential section 32i. The engagement sections 32c are, for example, each a plate-like section curved in a circular arc shape. The engagement sections 32c are, for example, arranged such that they are spaced apart from each other at equal angles about the axis of the inner circumferential section 32i. In the housing 2, part of the ventilation opening 5 is formed by a plurality (e.g., three) of projecting sections 5p, as shown in Figure 1. Fig.Figure 3 shows the arrangement. The projecting sections 5p are arranged such that they are spaced at equal angles to each other around an axis of the ventilation opening 5. A plurality of recesses 5r, which form part of the ventilation opening 5, are located between the projecting sections 5p. When attaching the ventilation component 1 to the housing 2, the ventilation component 1 is inserted into the ventilation opening 5 such that the engagement sections 32c each pass through the recesses 5r. The ventilation component 1 is then rotated by a predetermined angle around the axis of the inner circumferential section 32i such that the engagement sections 32c are directed towards the projecting sections 5p inside the housing 2, thereby attaching the ventilation component 1 to the housing 2. The projecting sections 5p and the engagement sections 32c interact to prevent the ventilation component 1 from detaching from the housing 2.

[0036] The vent valve 20 is attached to the inner circumferential section 32i such that it is in firm contact with an outer circumferential surface of the inner circumferential section 32i, which forms part of the support section 35. For example, the through-hole of the vent valve 20 has a diameter such that the vent valve 20 can be in contact with the outer circumferential surface of the inner circumferential section 32i.

[0037] The connecting section 32k, for example, has the valve seat section 36 and acts as a valve seat for the vent valve 20. The valve seat section 36 is arranged in a circumferential section of the connecting section 32k. The connecting section 32k has a flow path 32d, allowing gas to flow through it. The flow path 32d is designed such that it extends in the axial direction of the inner circumferential section 32i between the valve seat section 36 and the inner circumferential section 32i. The flow path 32d causes the vent valve 20 to be exposed to the pressure inside the housing 2.

[0038] The connecting section 32k further comprises, for example, an annular recess 32g. The sealing element 60 is received in the annular recess 32g. The annular recess 32g is formed in a lower surface of the connecting section 32k, for example, such that it overlaps with the valve seat section 36 in the direction perpendicular to the axis of the inner circumferential section 32i.

[0039] The outer circumferential section 32e extends along the axial direction of the inner circumferential section 32i outside the connecting section 32k. The outer circumferential section 32e has an outwardly projecting section 32j, which projects outward in the direction perpendicular to the axis of the inner circumferential section 32i.

[0040] The outer circumferential section 32e, for example, has a plurality of inwardly projecting sections 32v. The inwardly projecting sections 32v project inwards in the direction perpendicular to the axis of the inner circumferential section 32i at an end section of the outer circumferential section 32e in the axial direction of the inner circumferential section 32i. The inwardly projecting sections 32v are arranged such that they are spaced apart from each other at predetermined intervals around the axis of the inner circumferential section 32i.

[0041] As it is in the Fig. 1 and the Fig.As shown in Figure 2, the structural element 30 further comprises, for example, a third element 33. The third element 33 is, for example, a disc-shaped element. The third element 33, together with the first element 31 and the second element 32, forms the interior space 40. The gas-permeable membrane 10 and the ventilation valve 20 are, for example, contained within the interior space 40. The third element 33 covers and protects the gas-permeable membrane 10 and the ventilation valve 20.

[0042] The third element 33 has a cover 33c with a disc shape and an engagement claw 33e. The engagement claw 33e projects axially from an edge section of a main surface of the cover 33c. A tip section of the engagement claw 33e projects outwards in a direction perpendicular to an axis of the cover 33c. The third element 33 is inserted into the outer circumferential section 32e such that the engagement claw 33e passes through a gap between the inwardly projecting sections 32v. The third element 33 is then rotated about the axis of the cover 33c by a predetermined angle so that the tip section of the engagement claw 33e is directed towards the inwardly projecting sections 32v. In this way, the third element 33 is attached to the second element 32.The fact that the tip section of the engagement claw 33e is directed towards the inwardly projecting sections 32v prevents the third element 33 from detaching from the second element 32.

[0043] As it is in the Fig. As shown in Figure 1, the structural element 30 has a ventilation passage 50. The ventilation passage 50 allows the interior space 40 to be connected to an exterior space of the ventilation component 1 in such a way that ventilation can take place. The ventilation passage 50 is, for example, formed between the connecting section 32k and an inner surface of the outer circumferential section 32e.

[0044] Examples of materials for structural element 30 include a synthetic resin and a metal. A thermoplastic resin can be used as the synthetic resin. Examples of thermoplastic resins include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polysulfone (PS), polypropylene (PP), polyethylene (PE), and ABS resin. The material for structural element 30 can be a composite material containing the thermoplastic resin as a matrix. In this case, a reinforcing agent added to the composite material can be glass fibers, carbon fibers, a metal, or an inorganic filler.

[0045] As it is in the Fig.As shown in Figure 4, when the difference between the pressure inside the housing 2 and the pressure outside the housing 2 is less than the specified value, the vent valve 20 closes, making it impossible for the gas inside the housing 2 to move through the flow path 32d to the outside of the housing 2. Therefore, the gas enters and exits the housing 2 through a flow path that includes the mounting hole 32h of the inner circumferential section 32i, the through-hole 31h of the first element 31, the gas-permeable membrane 10, the interior 40, and the first vent path 50. In contrast, as shown in the Fig.Figure 5 shows that when the pressure difference between the inside of housing 2 and the pressure outside of housing 2 is equal to or greater than the specified value(s), the vent valve 20 opens and the gas inside housing 2 is discharged to the outside of housing 2 through a flow path that includes flow path 32d, the interior 40, and the first vent path 50. The gas-permeable membrane 10 is not located in the gas flow path formed when the vent valve 20 opens, and consequently, a large quantity of gas can be discharged from the inside of housing 2 in a short period of time. It should be noted that there is a case in which a rapid increase in pressure inside the housing could damage a gas-permeable membrane, etc., even when the vent valve is in operation. However, the venting component 1 has a structure that can inhibit such a phenomenon.To prevent damage to the gas-permeable membrane, etc., a structure can be provided that allows the gas inside the housing to be released to the outside of the housing via the vent valve. For this purpose, it is important to adjust the size of the cross-sectional area of ​​the flow path through which the gas passes and the size of the valve section of the vent valve that closes the flow path. The vent component 1 has an annular shape, in which the vent valve 20, when viewed in a plane, has a through-hole at its center. Furthermore, the vent component 1 has a structure in which the gas-permeable membrane 10 is accommodated such that, when viewed in a plane, the gas-permeable membrane 10 is positioned inwards from the inner circumferential surface that forms the through-hole of the vent valve 20.Consequently, the cross-section of the flow path through which the gas passes and the valve section of the vent valve 20 are ensured to be confined as much as possible within a limited space in the venting component 1. Therefore, if the pressure inside the housing 2 rises rapidly, the vent valve 20 opens and the gas is rapidly discharged to the outside of the housing 2 through the flow path, which includes the flow path 32d, the interior 40 and the vent path 50.

[0046] The ventilation component 1 can be modified in various ways. For example, the ventilation valve 20 can have a ring shape that differs from a ring shape when one of the two surfaces 20f and 20s is considered in a plane. In this case, part or all of the outline of each of the inner circumferential section 21 and the outer circumferential section 22 can be a curve, or it can be a straight line when one of the two surfaces 20f and 20s is considered in a plane.

Claims

[1] Ventilation component (1) to be attached to a housing (2) at a ventilation opening (5) of the housing (2), comprising: a gas-permeable membrane (10); a ventilation valve (20) comprising an elastic body and which is opened and closed by elastic deformation of the elastic body; and a structural element (30) that supports the gas-permeable membrane (10) and the ventilation valve (20), wherein in an installed state in which the ventilation component (1) is attached to the housing (2), ventilation is carried out between an inside of the housing (2) and an outside of the housing (2) by means of the gas-permeable membrane (10) and the ventilation valve (20) is opened to release a gas inside the housing (2) to the outside of the housing (2) when a difference between a pressure inside the housing (2) and a pressure outside the housing (2) is equal to or greater than a predetermined value, and the elastic body is made of a rubber whose rate of change of tensile strength, as determined by the formula (1) below, is 95% to 120%: Rate of change in tensile strength = 100 × first tensile strength / second tensile strength wherein the first tensile strength is a tensile strength determined when a test specimen made of the rubber, having a thickness of 2.0 mm and stamped into a No. 3 dumbbell shape, is heated according to the heat resistance test, method A, according to the Japanese Industrial Standard (JIS) K 6257:2010 and then subjected to a tensile test at a tensile speed of 500 mm / minute, and The second tensile strength is a tensile strength that is determined when the test specimen is subjected to a tensile test at a tensile speed of 500 mm / minute without being heated in accordance with the heat resistance test, procedure A. where the second tensile strength of the rubber is 5 to 10 MPa. [2] Ventilation component (1) according to claim 1, wherein the ventilation valve (20) comprises a plate-like structural section formed from the elastic body and having two surfaces (20f, 20s) pointing in respective directions opposite to each other, the structural section has a minimum thickness of 2.0 mm to 4.0 mm, and The rubber has a durometer hardness of A 30 to 80 according to JIS K 6253-3:2012. [3] Ventilation component (1) according to claim 1 or 2, wherein the ventilation valve (20) comprises a plate-like structural section formed from the elastic body and having two surfaces (20f, 20s) pointing in opposite directions and having a ring shape comprising an inner circumferential section (21) and an outer circumferential section (22) when one of the two surfaces (20f, 20s) is viewed in the plane, and the structural element (30) has a support section (35) that supports the inner circumferential section (21) and a valve seat section (36) that is in contact with the outer circumferential section (22) when the vent valve (20) is closed and that is not in contact with the outer circumferential section (22) when the vent valve (20) is open. [4] Ventilation component (1) according to one of claims 1 to 3, which further comprises a sealing element (60) that seals a gap between the structural element (30) and an outer surface (2s) of the housing (2) to which the ventilation component (1) is attached in the attached state, wherein the structural element (30) has an engagement section (32c) which is to be inserted into the ventilation opening (5) of the housing (2).

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