Ventilation structure

Abstract

In this provided ventilation structure, a ventilation component comprises: an internal member that includes an elastic material and has an open tube structure; and an external member that has a closed tube structure. The internal member is fixed to the external member in a state in which the internal member is inserted inside the external member and a ventilation path is ensured between the internal member and the external member. The ventilation component is fixed to a housing in a state in which a protrusion of the housing is inserted inside the internal member from one opening of the internal member, and an inner peripheral surface of the internal member and an outer peripheral surface of the protrusion are in contact with each other. The outer peripheral surface of the protrusion of the housing has a retreated portion or a rough surface portion that has been subjected to surface roughening. The retreated portion is located at a position separated from the leading end of the protrusion. The inner peripheral surface of the internal member is in contact with the rough surface portion or is, at the retreated portion, deformed in a direction approaching the axis of the ventilation component. This structure is advantageous for preventing the ventilation component from falling off from the protrusion of the housing.

Description

Ventilated structure

[0001] The present invention relates to a ventilation structure including a housing and a ventilation component.

[0002] Housings of automotive electrical components such as lamps, inverters, converters, electronic control units (ECUs), battery packs, radars, and cameras, as well as various electronic devices for home, medical, and office use, are sometimes provided with ventilation holes that connect the interior and exterior spaces of the housing. The ventilation holes ensure ventilation between the interior and exterior of the housing and mitigate pressure fluctuations within the housing. Patent Document 1 discloses a ventilation part that is fixed to the housing so as to cover the ventilation hole. By fixing the ventilation part, it is possible to prevent, for example, liquids such as water and oil, and dust from entering the interior of the housing through the ventilation hole.

[0003] FIG. 13 shows a conventional ventilation structure using the ventilation part of Patent Document 1. FIG. 13 shows a ventilation part 103, a portion of a housing 102 to which the ventilation part 103 is fixed, and the vicinity thereof. The ventilation structure 101 in FIG. 13 includes a housing 102 and a ventilation part 103. The housing 102 has, on its outer surface 109, a protrusion 108 that protrudes cylindrically toward an edge 107 of a ventilation hole 106 that connects an internal space 104 of the housing 102 with an external space 105. The ventilation part 103 includes an internal member 110 having an open tubular structure and an external member 114 having a closed tubular structure. The internal member 110 and the external member 114 are fixed to each other with a ventilation path 115 secured between them. The ventilation part 103 is fixed to the housing 102 with the protrusion 108 of the housing 102 inserted into the interior of the internal member 110 from one opening 111 of the internal member 110 and with the inner circumferential surface 112 of the internal member 110 abutting against the outer circumferential surface 113 of the protrusion 108. The ventilation part 103 is fixed so as to cover the ventilation hole 106, and prevents liquid and dust from entering the interior of the housing 102 through the ventilation hole 106 while ensuring ventilation 117 between the internal space 104 and the external space 105. Reference numeral 116 denotes a ventilation membrane.

[0004] International Publication No. 2021 / 145383

[0005] In a ventilation structure in which a ventilation component is fixed to a protrusion of a housing, there is a demand for preventing the ventilation component from unintentionally falling off the protrusion. The ventilation structure shown in Fig. 13 has room for reexamination from the perspective of preventing the above-mentioned falling off. The present invention aims to provide a ventilation structure including a housing and a ventilation component fixed to a protrusion of the housing, which is advantageous in preventing the ventilation component from falling off the protrusion.

[0006] The present invention provides a ventilation structure comprising a housing and a ventilation part, wherein the housing has, on its outer surface, a protrusion that protrudes cylindrically toward an edge of a ventilation hole that connects an internal space of the housing with an external space, the ventilation part comprises: an internal member containing an elastic material and having an open tubular structure; and an external member having a closed tubular structure, wherein the internal member is inserted into the external member and fixed to the external member in a state in which an air passage is secured between the internal member and the external member, the ventilation part is fixed to the housing in a state in which the protrusion of the housing is inserted into the internal member from one opening of the internal member and the inner peripheral surface of the internal member and the outer peripheral surface of the protrusion are in contact with each other, and the ventilation structure allows gas to circulate between the internal space and the external space via the air passage, the outer peripheral surface of the protrusion has a recessed portion or a roughened portion, and the recessed portion is located at a position spaced from the tip of the protrusion, The inner peripheral surface of the internal member is in contact with the roughened portion or is deformed in a direction approaching the axis of the ventilation part at the recessed portion.

[0007] The ventilation structure of the present invention is advantageous in preventing the ventilation part from falling off the protrusion.

[0008] 1 is a cross-sectional view schematically showing a ventilation structure of embodiment 1. FIG. 2 is an exploded perspective view schematically showing the ventilation structure of embodiment 1. FIG. 3 is a plan view schematically showing the state of the protrusions and recessed portions of the housing in embodiment 1. FIG. 4 is a schematic view for explaining the angle θ1 formed between a step that a protrusion of the housing may have and the axis O of the ventilation part. FIG. 5 is a cross-sectional view schematically showing a ventilation structure of embodiment 2. FIG. 6 is an exploded perspective view schematically showing the ventilation structure of embodiment 2. FIG. 7 is a plan view schematically showing the state of the protrusions and recessed portions of the housing in embodiment 2. FIG. 8 is a cross-sectional view schematically showing a ventilation structure of embodiment 3. FIG. 9 is an exploded perspective view schematically showing a ventilation structure of embodiment 3. FIG. 10 is a cross-sectional view schematically showing a ventilation structure of embodiment 4. FIG. 11 is a schematic view for explaining a method for evaluating the holding force of a ventilation structure. FIG. 12 is a cross-sectional view schematically showing the housing of example 1. FIG. 13 is a cross-sectional view schematically showing the housing of example 2. FIG. 14 is a cross-sectional view schematically showing a housing of a comparative example. FIG. 15 is a graph showing the insertion load evaluated in the examples. FIG. 16 is a cross-sectional perspective view showing an example of a conventional ventilation structure.

[0009] a ventilation structure according to a first aspect of the present invention, comprising: a housing and a ventilation part; the housing having, on its outer surface, a protrusion that protrudes cylindrically toward an edge of a ventilation hole that connects an internal space of the housing with an external space; the ventilation part comprising: an internal member that contains an elastic material and has an open tubular structure; and an external member that has a closed tubular structure; the internal member is inserted into the external member and fixed to the external member in a state in which an air passage is secured between the internal member and the external member; the ventilation part is fixed to the housing in a state in which the protrusion of the housing is inserted into the internal member from one opening of the internal member and the inner peripheral surface of the internal member and the outer peripheral surface of the protrusion are in contact with each other; and the ventilation structure allows gas to circulate between the internal space and the external space via the air passage; the outer peripheral surface of the protrusion has a recessed portion or a roughened surface portion, and the recessed portion is located at a position spaced from the tip of the protrusion; The inner peripheral surface of the internal member is in contact with the rough surface portion or is deformed in the recessed portion in a direction approaching the axis of the ventilation component.

[0010] In a second aspect of the present invention, for example, in the ventilation structure according to the first aspect, the outer surface of the protrusion has a step in the direction of the axis, and the recessed portion extends from the step in the direction of the outer surface of the housing.

[0011] In a third aspect of the present invention, for example, in the ventilation structure according to the first or second aspect, the recessed portion is formed over the entire circumferential section of the outer circumferential surface when viewed in a direction along the axis.

[0012] In a fourth aspect of the present invention, for example, in the ventilation structure according to the first or second aspect, the recessed portion is formed in a partial circumferential section of the outer circumferential surface when viewed in a direction along the axis.

[0013] In a fifth aspect of the present invention, for example, in the ventilation structure according to the first or second aspect, the recessed portion is formed by a spiral groove formed on the outer circumferential surface and extending in a direction along the axis.

[0014] In a sixth aspect of the present invention, for example, in the ventilation structure according to any one of the first to fifth aspects, the hardness of the elastic material is A75 or more, as expressed by a Type A durometer hardness measured in accordance with the provisions of JIS K6253-3:2012.

[0015] In a seventh aspect of the present invention, for example, in the ventilation structure according to any one of the first to sixth aspects, the ratio of the height to the inner diameter of the internal member is 1.0 or less.

[0016] In an eighth aspect of the present invention, for example, in the ventilation structure according to any one of the first to seventh aspects, the ventilation component further includes a ventilation membrane that covers the other opening of the internal member.

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following description is merely an example. The ventilation structure of the present invention is not limited to the specific embodiments shown below.

[0018] (Embodiment 1) A ventilation structure 1 (1A) of embodiment 1 is shown in Figures 1A and 1B. Figures 1A and 1B show a ventilation component 3, a portion of a housing 2 to which the ventilation component 3 is fixed, and the vicinity thereof. Figure 1B is an exploded perspective view showing the housing 2 and the ventilation component 3 separated along the axis O of the ventilation component 3. As shown in Figures 1A and 1B, the ventilation structure 1A includes the housing 2 and the ventilation component 3 fixed to a protrusion 23 of the housing 2.

[0019] The housing 2 has a cylindrical protrusion 23 that protrudes from an outer surface 24 toward an edge 22 of an air vent 21 that connects the internal space 11 and the external space 12 of the housing 2. An air passage 4B is provided inside the protrusion 23, extending in the direction in which the protrusion 23 protrudes. Gas can circulate between the internal space 11 and the air vent 21 via the air passage 4B.

[0020] The ventilation component 3 includes an internal member 31 and an external member 32. The internal member 31 includes an elastic material. In addition, the internal member 31 has an open tubular structure. In other words, the internal member 31 is a tubular member having openings 33 and 34 at both ends. The internal member 31 also has a protrusion 37. The protrusion 37 protrudes outward from the outer periphery of the open tubular structure on the outer periphery. In other words, the protrusion 37 protrudes outward in a direction perpendicular to the axis O. The protrusion 37 is formed around the entire periphery of the outer periphery of the open tubular structure of the internal member 31. In other words, the protrusion 37 is formed in an annular shape. However, the shape of the protrusion 37 is not limited to that shown in FIGS. 1A and 1B . The external member 32 has a closed tubular structure. In other words, the external member 32 is a tubular member with a bottom and an opening at only one end. The internal member 31 is inserted into the external member 32 and fixed to the external member 32 with an air passage 4A secured between the internal member 31 and the external member 32. The external member 32 has a hook 38 on the inner circumferential surface of the closed tubular structure. The hook 38 hooks the protrusion 37. The hooking of the protrusion 37 by the hook 38 can contribute to preventing the external member 32 from falling off the internal member 31. The external member 32 also has a plurality of through holes 36 formed across the side wall 39 and bottom wall 40 of the external member 32. Each through hole 36 passes through the side wall 39 and bottom wall 40 to connect the outer circumferential surface and inner circumferential surface of the external member 32. However, the shape and location of the through holes 36 are not limited to those shown in FIGS. 1A and 1B . Each through hole 36 is connected to the ventilation path 4A, and gas can flow between the external space 12 and the ventilation path 4A.

[0021] The ventilating component 3 is fixed to the housing 2 with the protrusion 23 of the housing 2 inserted into the interior of the internal member 31 through one opening 33 of the internal member 31 and the inner circumferential surface 35 of the internal member 31 abutting against the outer circumferential surface 25 of the protrusion 23. In the ventilated structure 1A, gas can flow between the internal space 11 and the external space 12 via the ventilation path 4A. More specifically, when viewed from the internal space 11 side, gas 51 can pass through the ventilation path 4B, the ventilation path 4A, and the through-hole 36 in that order. The ventilating component 3 of the first embodiment further includes a ventilation membrane 6 covering the other opening 34 of the internal member 31. The gas 51 flowing between the internal space 11 and the external space 12 permeates the ventilation membrane 6. When viewing the ventilating component 3 in the direction along the axis O, the bottom wall 40 of the external member 32 covers the ventilation opening 21 of the housing 2 and the other opening 34 of the internal member 31. The bottom wall 40 also covers the breathable membrane 6 .

[0022] In the ventilation structure 1A, the outer peripheral surface 25 of the protrusion 23 has a recessed portion 5. The recessed portion 5 is located at a position spaced apart from the tip 26 of the protrusion 23. The recessed portion 5 is recessed in a direction approaching the axis O compared to a portion A of the outer peripheral surface 25 adjacent to the recessed portion 5 and located away from the outer surface 24 of the housing 2. The inner peripheral surface 35 of the internal member 31 is deformed in a direction approaching the axis O at the recessed portion 5. The deformed inner peripheral surface 35 is in contact with the recessed portion 5. However, the deformed inner peripheral surface 35 does not have to be in contact with the recessed portion 5. The deformation is usually elastic deformation. The deformation of the inner peripheral surface 35 contributes to preventing the ventilation part 3 from falling off the protrusion 23.

[0023] The recessed portion 5 in the first embodiment extends from a step 27 that the outer peripheral surface 25 of the protrusion 23 has in the direction of the axis O toward the outer surface 24 of the housing 2. The recessed portion 5 is recessed toward the axis O compared to the outer peripheral surface 25 at a position adjacent to the recessed portion 5 across the step 27. Furthermore, the recessed portion 5 in the first embodiment is formed over the entire circumferential length of the outer peripheral surface 25 when viewed along the axis O (see FIG. 2 ; FIG. 2 is a plan view of only the protrusion 23 of the housing 2 viewed along the axis O. However, for clarity, the tapered surface near the tip 26 of the protrusion 23 is omitted). The recessed portion 5 formed over the entire circumferential length is particularly suitable for preventing the ventilating component 3 from falling off the protrusion 23. Furthermore, according to the inventors' investigations, the recessed portion 5 is also particularly suitable for reducing the force required to secure the ventilating component 3 to the protrusion 23 (hereinafter referred to as the "insertion load"). In other words, the ventilation structure 1A is particularly suitable for preventing the ventilation component 3 from falling off the protrusion 23 while making it easy to fix the ventilation component 3 to the protrusion 23 of the housing 2 .

[0024] The degree of recession of the recessed portion 5 is represented by a distance D1 between the recessed portion 5 and portion A (a portion of the outer peripheral surface 25 adjacent to the recessed portion 5 and located away from the outer surface 24 of the housing 2) when viewed in a direction along the axis O, and may be, for example, 0.01 to 2.0 mm, or may be 0.05 to 1.5 mm, 0.1 to 1.3 mm, 0.15 to 1.1 mm, 0.2 to 1.0 mm, 0.3 to 0.9 mm, or even 0.4 to 0.8 mm. Distance D1 can be determined as the maximum value of the distance between P and Q when viewing the ventilation structure 1A in a direction along the axis O and rotating an imaginary line segment L extending from the axis O once around the outer peripheral surface 25, with P representing the intersection of the recessed portion 5 and Q representing the intersection of the line segment L with portion A (see FIG. 2 ).

[0025] When the protrusion 23 has the step 27, when viewing the protrusion 23 in a direction perpendicular to the axis O, the angle θ1 (see FIG. 3 ) formed between the step 27 and the direction D2 in which the receding portion 5 extends toward the tip 26 is, for example, 30 to 150 degrees, and may be 45 to 135 degrees, 60 to 120 degrees, 75 to 110 degrees, or even 80 to 105 degrees. The angle θ1 may be an obtuse angle or may be 90 degrees.

[0026] The height H1 of the protrusion 23 is, for example, 3.0 to 12.0 mm. The upper limit of the height H1 may be 10.0 mm or less, 9.0 mm or less, 8.0 mm or less, 7.0 mm or less, 6.0 mm or less, 5.0 mm or less, or even 4.0 mm or less. The lower limit of the height H1 may be 3.5 mm or more, 4.0 mm or more, 4.5 mm or more, or even 5.0 mm or more. The height H1 may be 9.0 mm or less. According to the inventors' investigations, when the height H1 is 9.0 mm or less, the ventilating part 3 is likely to fall off. Therefore, in the above case, it is particularly advantageous for the outer peripheral surface 25 of the protrusion 23 to have the recessed portion 5. The height H1 can be specified as the maximum distance along the axis O between the outer surface 24 of the housing 2 and the tip 26 of the protrusion 23.

[0027] The minimum length L1 of a portion B of the outer peripheral surface 25 of the protrusion 23 that abuts against the inner peripheral surface 35 of the internal member 31, the portion B being located above the recessed portion 5 and farthest from the axis O, as viewed in a direction along the axis O, is, for example, 0.3 mm or more. A length L1 of 0.3 mm or more can contribute to ensuring a seal between the protrusion 23 and the internal member 31, in other words, ensuring a seal between the housing 2 and the ventilated component 3. The upper limit of the length L1 is, for example, 10.0 mm or less, and may be 8.0 mm or less, 5.0 mm or less, 3.0 mm or less, 2.0 mm or less, 1.5 mm or less, 1.2 mm or less, 1.0 mm or less, or even 0.8 mm or less. In this specification, "upward" refers to the direction in which the axis O extends from the outer surface 24 of the housing 2 toward the tip 26 of the protrusion 23.

[0028] The ratio L1 / H1 of the length L1 to the height H1 of the protrusion 23 is, for example, 0.05 to 0.8, and may be 0.07 to 0.5, 0.09 to 0.3, or even 0.1 to 0.2.

[0029] Each component included in the ventilation structure 1A will be described in more detail.

[0030] Examples of materials that constitute the housing 2 include resin, metal, and composite materials thereof. The same applies to examples of materials that constitute the protrusions 23. However, the materials are not limited to the above examples. The material that constitutes the parts of the housing 2 other than the protrusions 23 may be the same as or different from the material that constitutes the protrusions 23. The elastic modulus of the material that constitutes the protrusions 23 is typically greater than the elastic modulus of the elastic material contained in the internal member 31.

[0031] Known methods can be applied to form the housing 2, the protrusions 23, and the recessed portions 5. A combination of methods may be used, and the forming method is not limited. For example, a housing 2 containing metal may be formed by die-casting. Die-casting also makes it possible to form a housing 2 having protrusions 23 with recessed portions 5. The recessed portions 5 may be formed by post-processing a protrusion that does not have a recessed portion 5. Examples of post-processing include cutting, milling, and machining.

[0032] Examples of the housing 2 include housings for in-vehicle electrical components such as lamps, inverters, converters, ECUs (Electronic Control Units), battery packs, radars, and cameras. The housing 2 may also be housings for various electronic devices for home, medical, office, etc. The housing 2 is not limited to the above examples.

[0033] The inner diameter R1 of the internal member 31 is, for example, 5.0 to 10.0 mm, and may be 6.0 to 9.0 mm, 7.0 to 8.0 mm, 7.0 to 7.5 mm, 7.25 to 7.6 mm, 7.25 to 7.45 mm, or even 7.3 to 7.45 mm. The inner diameter R1 can be specified as the inner diameter of the portion of the internal member 31 that is in contact with the portion of the protrusion 23 with the largest outer diameter when viewed in the direction along the axis O. However, the inner diameter R1 is specified in a state where the ventilation component 3 is fixed to the protrusion 23 so as to be closest to the outer surface 24 of the housing 2. At this time, the internal member 31 and the outer surface 24 may be in contact with each other, as shown in FIG. 1A .

[0034] The height H2 of the internal member 31 is, for example, 4.0 to 13.0 mm. The lower limit of the height H2 may be 4.2 mm or more, 4.5 mm or more, 4.8 mm or more, 5.0 mm or more, 7.0 mm or more, 8.0 mm or more, 9.0 mm or more, or even 10.0 mm or more. The upper limit of the height H2 may be 12.0 mm or less, 10.0 mm or less, 8.0 mm or less, 6.0 mm or less, 5.8 mm or less, 5.5 mm or less, 5.3 mm or less, 5.0 mm or less, or even 4.8 mm or less. The height H2 may be 4.0 to 5.0 mm, or 4.2 to 4.8 mm. The height H2 can be specified as the maximum length of the internal member 31 in the direction along the axis O. The height H2 typically corresponds to the distance between one opening 33 and the other opening 34 of the internal member 31 having an open-tube structure in the direction along the axis O.

[0035] The ratio H2 / R1 of the height H2 to the inner diameter R1 of the internal member 31 is, for example, 1.7 or less, and may be 1.5 or less, 1.2 or less, 1.0 or less, 0.9 or less, 0.8 or less, or even 0.7 or less. The lower limit of the ratio H2 / R1 is, for example, 0.4 or more. According to the inventors' studies, when the ratio H2 / R1 is 1.0 or less, or even 0.9 or less, the ventilating part 3 is more likely to fall off. For this reason, in the above case, it is particularly advantageous for the outer peripheral surface 25 of the protrusion 23 to have the recessed portion 5.

[0036] An example of an elastic material that can be included in the internal member 31 is an elastomer (elastic resin). The elastomer may be rubber. Examples of the elastomer include nitrile rubber (NBR), ethylene-propylene rubber (EPDM), silicone rubber, fluororubber, acrylic rubber, hydrogenated rubber, or various thermoplastic elastomers. Examples of thermoplastic elastomers are polyester-based elastomers (TPEE; also referred to as TPC), polystyrene-based elastomers (TPS), polyolefin-based elastomers (TPO), and polyamide-based elastomers (TPAE). The elastic material may be TPEE. When considering use as the internal member 31, TPEE has a particularly excellent balance between heat resistance and mechanical properties.

[0037] The elastic material typically has a hardness of D70 or less, as measured by a Type D durometer hardness in accordance with the Japanese Industrial Standards (hereinafter referred to as JIS) K6253-3:2012. The hardness of the elastic material may be A55 or more, A65 or more, or even A75 or more, as measured by a Type A durometer hardness in accordance with JIS K6253-3:2012. The hardness of the elastic material may be D25 or more, D30 or more, D35 or more, D40 or more, or even D45 or more, as measured by a Type D durometer hardness. Having the hardness of the elastic material contained in the internal member 31 in a range equal to or greater than the above-described lower limit increases the frictional force between the outer peripheral surface 25 of the protrusion 23 and the inner peripheral surface 35 of the internal member 31, which can contribute to preventing the ventilating component 3 from falling off the protrusion 23. On the other hand, as the hardness of the elastic material increases, the force required to fix the ventilating component 3 to the protrusion 23 tends to increase. However, the recessed portion 5 is also suitable for reducing the insertion load when fixing the ventilating component 3 to the protrusion 23. In other words, when the hardness of the elastic material contained in the internal member 31 is in a range equal to or greater than the above-mentioned lower limit, the advantage of the outer peripheral surface 25 of the protrusion 23 having the recessed portion 5 is particularly great.

[0038] The heat resistance of the elastic material is expressed by the Vicat softening temperature (VST) measured in accordance with the A50 method of JIS K7206:2016, and is, for example, 70°C or higher. The upper limit of VST is, for example, 210°C or lower. The VST can be specified in accordance with JIS K7206:2016.

[0039] The internal member 31 may contain materials other than elastic materials. Examples of such materials include resins other than elastic materials, pigments such as carbon black and titanium white, reinforcing fillers such as glass particles and glass fibers, and additives such as water repellents. However, the materials that the internal member 31 can contain are not limited to the above examples.

[0040] The configuration of the internal member 31 is not limited to the above example, as long as it contains an elastic material, has an open tube structure, can be inserted into the external member 32 and fixed to the external member 32 with the air passage 4A secured between it and the external member 32, the protrusion 23 of the housing 2 can be inserted into the internal member from one opening 33, and the internal member 31 can be fixed to the housing 2 with the inner circumferential surface 35 and the outer circumferential surface 25 of the protrusion 23 abutting against each other, and gas can circulate between the internal space 11 and the external space 12 via the air passage 4A. For example, the internal member may have the configuration disclosed in Patent Document 1.

[0041] An example of a material that the external member 32 may contain is a resin. Examples of resins include thermoplastic resins and the above-mentioned elastomers. Examples of thermoplastic resins include polyamide (PA) such as nylon, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polycarbonate (PC), polypropylene (PP), and polyphenylene ether (PPE). The material contained in the external member 32 may be the same as or different from the material contained in the internal member 31. The external member 32 may contain pigments such as carbon black and titanium white, reinforcing fillers such as glass particles and glass fiber, and additives such as a water repellent. However, the materials that the external member 32 may contain are not limited to the above examples.

[0042] The configuration of the external member 32 is not limited to the above example, as long as it has a closed tube structure, the internal member 31 can be inserted inside and fixed in place with the ventilation path 4A secured between the internal member 31, and gas can pass between the internal space 11 and the external space 12 via the ventilation path 4A. For example, the external member may have the configuration disclosed in Patent Document 1.

[0043] Although the breathable membrane 6 is not necessarily a necessary component, an embodiment in which the breathable membrane 6 is disposed in the flow path of the gas 51 between the external space 12 and the internal space 11 is particularly suitable for preventing foreign matter from entering the internal space 11 from the external space 12. Examples of foreign matter include liquids such as water and oil, and dust.

[0044] Examples of the breathable membrane 6 include woven fabric, nonwoven fabric, mesh, and porous membrane. The breathable membrane 6 may have a laminated structure of two or more membranes. The breathable membrane 6 may include a porous membrane and at least one layer selected from the group consisting of woven fabric, nonwoven fabric, and mesh. Examples of materials constituting the breathable membrane 6 include organic polymer materials. Examples of organic polymer materials include fluororesins, polyolefins, polyesters, polyamides, and ethylene vinyl acetate. Examples of fluororesins include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, and tetrafluoroethylene-ethylene copolymers. Examples of polyolefins include homopolymers and copolymers of ethylene, propylene, and 4-methylpentene-1,1 butene. Examples of polyamides include nylon and aramid. The breathable membrane 6 may include nanofibers. Examples of nanofibers include nanofibers containing various resins such as polyacrylonitrile, nylon, and polylactic acid. Porous membranes can be produced by known stretching or extraction methods.

[0045] The breathable membrane 6 may include a porous PTFE membrane. The porous PTFE membrane has a particularly excellent balance between breathability per unit area and the ability to prevent the intrusion of foreign matter. The breathable membrane 6 may have a laminated structure of the porous PTFE membrane and a breathable support material such as a nonwoven fabric.

[0046] The thickness of the breathable membrane 6 is, for example, 1 μm or more and 5 mm or less. The breathable membrane 6 has an air permeability of, for example, 0.1 to 300 seconds / 100 mL, expressed as a Gurley air permeability measured in accordance with the air permeability measurement method B (Gurley method) specified in JIS L1096:2020. However, the thickness and air permeability of the breathable membrane 6 are not limited to the above ranges.

[0047] The breathable membrane 6 may be subjected to a liquid-repellent treatment. The liquid-repellent treatment may be performed on at least a portion of the surface of the internal member 31 and / or the external member 32. The liquid-repellent treatment of the breathable membrane 6, the internal member 31, and the external member 32 can be performed by a known method.

[0048] 1A and 1B is bonded to the end surface of the internal member 31 so as to cover the other opening 34 of the internal member 31. Various welding methods such as heat welding, ultrasonic welding, and laser welding can be used to bond the breathable membrane 6. Bonding may also be performed using an adhesive, a pressure-sensitive adhesive, double-sided adhesive tape, or the like. The internal member 31 to which the breathable membrane 6 is bonded may be formed by insert molding.

[0049] The outer diameter R2 of the ventilation component 3 is, for example, 10.0 to 20.0 mm, and may be 11.0 to 19.0 mm, 12.0 to 18.0 mm, 13.0 to 17.0 mm, 14.0 to 16.0 mm, 14.5 to 15.5 mm, or even 14.7 to 15.1 mm. The outer diameter R2 can be specified as the maximum width of the ventilation component 3 when viewed in a cross section along the axis O. The outer diameter R2 of the ventilation component 3 shown in FIGS. 1A and 1B is the maximum distance between the opposing side walls 39 of the external member 32 shown in FIG. 1A. However, the outer diameter R2 is specified in a state in which the ventilation component 3 is fixed to the protrusion 23 so as to be closest to the outer surface 24 of the housing 2.

[0050] The height H3 of the ventilation component 3 is, for example, 5.0 to 15.0 mm, and may be 5.2 to 13.0 mm, 5.5 to 10.0 mm, 5.7 to 9.0 mm, 5.5 to 8.0 mm, 5.7 to 7.5 mm, 6.0 to 7.0 mm, or even 6.2 to 6.8 mm. The height H3 can be determined as the maximum distance between the lower end and the upper end of the ventilation component 3 when viewed in the direction along the axis O. However, the height H3 is determined in a state where the ventilation component 3 is fixed to the protrusion 23 so as to be closest to the outer surface 24 of the housing 2. The lower end and the upper end of the ventilation component 3 shown in FIGS. 1A and 1B are located at one opening 33 of the inner member 31 and the bottom wall 40 of the outer member 32, respectively.

[0051] The ratio H3 / R2 of the height H3 to the outer diameter R2 of the ventilation component 3 is, for example, 1.0 to 4.0, and may be 1.5 to 3.5, 1.7 to 3.0, 1.9 to 2.7, 2.0 to 2.5, or even 2.15 to 2.45.

[0052] The ventilation part 3 is not limited to the above example, as long as the protrusion 23 of the housing 2 is inserted into the interior of the internal member 31 from one opening 33 of the internal member 31, and the inner circumferential surface 35 of the internal member 31 and the outer circumferential surface 25 of the protrusion 23 are in contact with each other, and communication between the internal space 11 and the external space 12 via the ventilation path 4A is possible when the ventilation part 3 is fixed to the protrusion 23. For example, the ventilation part disclosed in JP 2001-143524 A or WO 2020 / 075848 A may be used.

[0053] (Embodiment 2) A ventilation structure 1 (1B) of embodiment 2 is shown in Figures 4A and 4B. Figures 4A and 4B show a ventilation component 3, a portion of the housing 2 to which the ventilation component 3 is fixed, and the vicinity thereof. Figure 4B is an exploded perspective view showing the housing 2 and the ventilation component 3 separated along the axis O. The ventilation structure 1B is the same as the ventilation structure 1A of embodiment 1, except for the shape of the recessed portion 5 that the protrusion 23 of the housing 2 has on the outer peripheral surface 25. Explanations that overlap with embodiment 1 will be omitted.

[0054] The recessed portion 5 in FIGS. 4A and 4B extends from a step 27 that the outer peripheral surface 25 of the protrusion 23 has in the direction of the axis O toward the outer surface 24 of the housing 2. The recessed portion 5 is recessed toward the axis O compared to a portion A of the outer peripheral surface 25 that is located adjacent to the recessed portion 5 across the step 27. The recessed portion 5 in FIGS. 4A and 4B is formed in a partial circumferential section of the outer peripheral surface 25 when viewed along the axis O (see FIG. 5 ; FIG. 5 is a plan view of only the protrusion 23 of the housing 2 as viewed along the axis O. However, for clarity of the drawing, the tapered surface near the tip 26 of the protrusion 23 is omitted from the illustration). According to the inventors' investigations, the recessed portion 5 of the second embodiment is also suitable for reducing the force required to fasten the ventilating component 3 to the protrusion 23.

[0055] 5, the step 27 of the second embodiment extends linearly when viewed in the direction along the axis O. Furthermore, the step 27 connects two points S and T on the circumference of the outer peripheral surface 25 when viewed in the direction along the axis O. The angle θ2, which is ∠SOT, is, for example, 10 to 120 degrees, and may be 30 to 100 degrees, 45 to 90 degrees, 50 to 80 degrees, or 55 to 70 degrees. However, the step 27 is not limited to the above example, and may extend, for example, in a curved or zigzag shape.

[0056] The extent to which the recessed portion 5 is recessed from the outer circumferential surface 25 may be the same as in embodiment 1. The extent to which it is recessed may be represented by a distance D1.

[0057] (Embodiment 3) A ventilation structure 1 (1C) of embodiment 3 is shown in Figures 6A and 6B. Figures 6A and 6B show a ventilation component 3, a portion of the housing 2 to which the ventilation component 3 is fixed, and the vicinity thereof. Figure 6B is an exploded perspective view showing the housing 2 and the ventilation component 3 separated along the axis O. The ventilation structure 1C is the same as the ventilation structure 1A of embodiment 1, except for the shape of the recessed portion 5 that the protrusion 23 of the housing 2 has on the outer peripheral surface 25. Duplicate explanations will be omitted.

[0058] 6A and 6B is formed by a spiral groove 8 formed on the outer circumferential surface 25 of the protrusion 23 and extending in a direction along the axis O. According to the studies of the present inventors, the recessed portion 5 of embodiment 3 is also suitable for reducing the force required to fix the ventilating component 3 to the protrusion 23.

[0059] The degree to which the recessed portion 5 is recessed may be the same as in embodiment 1. The degree to which it is recessed may be constant or may vary along the length of the groove 8. Furthermore, the interval (pitch) between adjacent grooves 8 in the direction along the axis O may be constant or may vary along the length of the groove 8.

[0060] 7 shows a ventilation structure 1 (1D) of embodiment 4. The ventilation structure 1D is the same as the ventilation structure 1A of embodiment 1, except that the outer peripheral surface 25 of the protrusion 23 of the housing 2 has a rough surface portion 7 instead of the recessed portion 5, and the inner peripheral surface 35 of the internal member 31 is in contact with the rough surface portion 7. Explanations that overlap with embodiment 1 will be omitted.

[0061] The rough surface portion 7 is a roughened region on the outer peripheral surface 25. The surface roughness of the rough surface portion 7 is usually greater than the roughness of the outer surface 24 of the housing 2. The contact of the inner peripheral surface 35 with the rough surface portion 7 contributes to preventing the ventilating part 3 from falling off from the protrusion 23. The roughening of the outer peripheral surface 25 can be performed by known techniques such as blasting or oxidation. The surface roughness of the rough surface portion 7 may be evaluated using a non-contact evaluation device, for example, a magnifying observation device such as a confocal laser microscope. The maximum height of the rough surface portion 7 evaluated using the magnifying observation device may be, for example, 6.3 μm or more.

[0062] The rough surface portion 7 may be formed over the entire outer peripheral surface 25 or may be formed over only a portion thereof. Furthermore, the rough surface portion 7 may be formed over the entire circumferential section of the outer peripheral surface 25 or may be formed over only a portion thereof when viewed in the direction along the axis O. The rough surface portion 7 in Fig. 7 is formed over the entire circumferential section of the outer peripheral surface 25, in other words, is ring-shaped. However, the shape of the rough surface portion 7 is not limited to the above example.

[0063] The ventilation structure of the present invention may have various modifications other than those described above. For example, the recessed portion 5 and the roughened surface portion 7 may be combined, in other words, the outer peripheral surface 25 of the protrusion 23 of the housing 2 may have both the recessed portion 5 and the roughened surface portion 7. At least a portion of the surface of the recessed portion 5 may be roughened.

[0064] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the specific examples shown below.

[0065] In this example, the retention force and insertion load of the ventilation structure were evaluated. The retention force is an index of the degree to which the ventilation component 3 is prevented from falling off the protrusion 23 of the housing 2 in the ventilation structure. The insertion load is an index of the force required to secure the ventilation component 3 to the protrusion 23 of the housing 2 in the ventilation structure. The evaluation methods for the retention force and insertion load are described below.

[0066] [Retention Force] A ventilation component 3 for evaluation was prepared, having the structure shown in FIGS. 1A and 1B . The internal member 31 was made of TPEE, and the inner diameter R1 of the internal member 31 was 7.35 mm and the height H2 was 4.5 mm. Next, the ventilation component 3 was manually pressed into the protrusion 23 of a separately prepared housing 2 to secure it. The ventilation component 3 was secured so that the protrusion 23 was inserted through one opening 33 of the internal member 31 and the end of the internal member 31 on the opening 33 side was in contact with the outer surface 24 of the housing 2. Next, the housing 2 was attached to the stage of an autograph testing machine (manufactured by Shimadzu Corporation), and the lower end 41 of the external member 32 of the ventilation component 3 was connected to a chuck of the testing machine (see FIG. 8 ; reference numeral 61 in FIG. 8 is the chuck of the testing machine). A test was conducted to pull the ventilation component 3 out of the protrusion 23 at a constant speed (200 mm / min). The pulling direction was the direction of extension of the axis O of the ventilation component 3. The maximum load measured from the start to the end of the pull-out was determined as the holding strength of the ventilated structure.

[0067] [Insertion Load] A ventilation part 3 identical to that used to evaluate the retention force was prepared. Next, a separately prepared housing 2 was attached to the stage of an autograph testing machine (manufactured by Shimadzu Corporation). The housing 2 was attached so that the protrusion 23 faced upward. Next, the prepared ventilation part 3 was attached to the chuck of the testing machine and lowered at a constant speed (50 mm / min). The protrusion 23 was inserted through one opening 33 of the internal member 31 and fixed to the protrusion 23. The load measured during insertion corresponds to the insertion load. The direction of descent was the direction of extension of the axis O of the ventilation part 3. The ventilation part 3 was lowered at a constant speed until the end of the internal member 31 on the opening 33 side came into contact with the outer surface 24 of the housing 2.

[0068] Example 1 A housing 2 having a protrusion 23 shown in Figure 9 was prepared. The prepared housing 2 corresponds to embodiment 1. The housing 2 was made of aluminum and was integrally molded by die-casting, including the protrusion 23 and the recessed portion 5. The maximum outer diameter of the protrusion 23 was 8.2 mm, the height was 4 mm, the length L1 of the outer peripheral surface 25 of the protrusion 23 was 0.5 mm, the distance from the outer surface 24 of the housing 2 to the step 27 in the direction along the axis O was 2.5 mm, and the recession amount of the recessed portion 5, represented by D1, was 0.2 mm. In addition, the connecting portion between the tip 26 of the protrusion 23 and the outer peripheral surface 25 was tapered to a diameter of 1.0 mm.

[0069] Example 2 A housing 2 having a protrusion 23 shown in FIG. 10 was prepared. The prepared housing 2 corresponds to embodiment 2. The housing 2 was made of aluminum and formed by die-casting. The recessed portion 5 was formed by cutting the protrusion formed by die-casting. The maximum outer diameter of the protrusion 23 was 8.2 mm, the height was 4 mm, the length L1 of the outer peripheral surface 25 of the protrusion 23 was 0.5 mm, the distance from the outer surface 24 of the housing 2 to the step 27 in the direction along the axis O was 2.5 mm, the recession amount of the recessed portion 5, represented by D1, was 0.4 mm, and the angle θ2 of the recessed portion 5 was 70 degrees. In addition, the connection portion between the tip 26 of the protrusion 23 and the outer peripheral surface 25 was tapered with a diameter of 1.0 mm.

[0070] Comparative Example A housing having a protrusion shown in Fig. 11 was prepared. The protrusion of the prepared housing was the same as the protrusion 23 of the housing 2 of Example 1, except that the recessed portion 5 was not formed.

[0071] The evaluation results of the holding force and insertion load for the example and comparative example are shown in Table 1 and Fig. 12, respectively. Note that the insertion load was evaluated only for example 1 and the comparative example. The insertion distance shown in Fig. 12 corresponds to the insertion depth of the protrusion 23 into the internal member 31, based on the position where the internal member 31 contacts the tip 26 of the protrusion 23.

[0072]

[0073] As shown in Table 1, the retention force of Examples 1 and 2 was higher than that of the Comparative Example. Also, as shown in Fig. 12, the insertion load of Example 1 was lower than that of the Comparative Example, and became almost constant once the insertion distance reached 2 mm, and further increase was suppressed.

Claims

1. A ventilation structure comprising a housing and a ventilation part, wherein the housing has a protrusion on its outer surface that protrudes in a cylindrical shape toward an edge of a ventilation hole that connects an internal space of the housing to an external space, the ventilation part comprises: an internal member containing an elastic material and having an open tubular structure; and an external member having a closed tubular structure, wherein the internal member is inserted into the external member and fixed to the external member in a state in which an air passage is secured between the internal member and the external member, the ventilation part is fixed to the housing in a state in which the protrusion of the housing is inserted into the internal member from one opening of the internal member and the inner peripheral surface of the internal member and the outer peripheral surface of the protrusion are in contact with each other, and the ventilation structure allows gas to circulate between the internal space and the external space via the air passage, the outer peripheral surface of the protrusion has a recessed portion or a roughened surface portion, and the recessed portion is located at a position spaced from the tip of the protrusion, The inner circumferential surface of the internal member is in contact with the rough surface portion, or is deformed in a direction approaching an axis of the ventilation part at the recessed portion.

2. The ventilation structure according to claim 1, wherein the outer peripheral surface of the protrusion has a step in the direction of the axis, and the recessed portion extends from the step in the direction of the outer surface of the housing.

3. A ventilation structure as described in claim 1, wherein the recessed portion is formed over the entire circumferential section of the outer circumferential surface when viewed in the direction along the axis.

4. A ventilation structure as described in claim 1, wherein the recessed portion is formed in a partial circumferential section of the outer peripheral surface when viewed in a direction along the axis.

5. The ventilation structure according to claim 1, wherein the recessed portion is formed by a spiral groove formed on the outer circumferential surface and progressing in a direction along the axis.

6. The ventilation structure according to claim 1, wherein the hardness of the elastic material is A75 or more, expressed by a type A durometer hardness measured in accordance with the provisions of JIS K6253-3:2012.

7. The ventilated structure according to claim 1, wherein the ratio of height to inner diameter of said inner member is 1.0 or less.

8. The ventilation structure according to claim 1, wherein the ventilation part further comprises a ventilation membrane covering the other opening of the internal member.

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