Ventilation component

A ventilation component 1 includes a ventilation path 10 for allowing ventilation between an inner space 2u and an outer space 2s of a housing 2. The ventilation path 10 is a path for allowing ventilation between the internal space 2u and the outer space 2s when the ventilation component 1 is attached to an edge 2f. The ventilation component 1 includes a supporting portion 12, a gas-permeable membrane 11, a protruding portion 13, and a sealing member 14. The supporting portion 12 surrounds the ventilation path 10. The gas-permeable membrane 11 is bonded to the supporting portion 12 and closes the ventilation path 10 in a ventilatable manner. The protruding portion 13 is a part having a tubular shape, the part being arranged to protrude from the supporting portion 12 and surround one end of the ventilation path 10, the part being configured to be in contact with the edge 2f when the ventilation component 1 is attached to the edge 2f. The ventilation component 1 satisfies requirements 2.5≤Gs/Gt≤5.0 and 1.0≤{(Gs−Gt)/2}/Lt≤3.0.

TECHNICAL FIELD

The present invention relates to a ventilation component.

BACKGROUND ART

Ventilation components configured to be attached to an edge of an opening of a housing have been known. Ventilation components can be used, for example, in devices such as vehicle lamps, inverters, converters, electronic control units (ECUs), battery packs, millimeter-wave radars, and vehicle-mounted cameras to eliminate a pressure difference occurring between the inside and the outside of the devices due to a temperature variation. These devices are sometimes required to prevent substances such as foreign matters, water, oil, and salt from entering the devices. In response to such a request, ventilation components are attached to housings of the devices.

Patent Literature 1 describes a vehicle lamp including a gas-permeable cap. In this gas-permeable cap, a substantially tubular body is fitted in a tubular cover component having a bottom. Additionally, a ventilation path is arranged between the inner circumference of the tubular cover component having a bottom and the outer circumference of the substantially tubular body and between a bottom face of the tubular cover component having a bottom and a bottom portion of the substantially tubular body. A mounting portion configured to be attached to a mounting opening of a housing is arranged at a top of the substantially tubular body.

Patent Literature 2 describes a ventilation member including a gas-permeable membrane through which gas passing an opening portion of a housing permeates in a state where the ventilation member is fixed to the opening portion. The ventilation member further includes a support including a supporting portion supporting the gas-permeable membrane and an insertion portion configured to be inserted in the opening portion. The insertion portion is divided at least on the insertion starting side thereof into a plurality of parts arranged circumferentially.

Patent Literature 3 describes a ventilation member configured to be attached to a housing requiring ventilation. The ventilation member includes a support, a gas-permeable membrane, and a cover component. The support includes a through hole serving as a ventilation path communicating the inside and the outside of the housing. The gas-permeable membrane is disposed on the support such that the gas-permeable membrane closes one opening of the through hole of the support. The cover component covers the support over the gas-permeable membrane. The support includes a plurality of leg portions. The support can be fixed to the housing by inserting the leg portions into the opening portion of the housing.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The techniques described in Patent Literatures 1 to 3 leave room for reexamination in terms of preventing breakage of the ventilation components at the time of inserting the ventilation components at a slant angle to an axis of an opening of a housing.

Therefore, the present invention provides a ventilation component that is advantageous in preventing breakage of the ventilation component at the time of inserting the ventilation component at a slant angle to an axis of an opening of a housing.

Solution to Problem

The present invention provides a ventilation component configured to be attached to an edge of an opening of a housing, the opening communicating an inner space and an outer space of the housing, the ventilation component comprising:a ventilation path for allowing ventilation between the inner space and the outer space when the ventilation component is attached to the edge;a supporting portion surrounding the ventilation path;a gas-permeable membrane bonded to the supporting portion and closing the ventilation path in a ventilatable manner;a protruding portion having a tubular shape, the protruding portion being arranged to protrude from the supporting portion and surround one end of the ventilation path, the protruding portion being configured to be in contact with the edge when the ventilation component is attached to the edge; anda sealing member disposed around the protruding portion, the sealing member configured to seal a gap between an outer surface of the housing and the ventilation component when the ventilation component is attached to the edge, whereinthe ventilation component satisfies requirements 2.5≤Gs/Gt≤5.0 and 1.0≤{(Gs−Gt)/2}/Lt≤3.0, where Gt is a maximum outer diameter of the protruding portion in a boundary between the protruding portion and the supporting portion, Gs is a maximum outer diameter of an outer surface of the supporting portion in contact with the protruding portion and is defined when the outer surface of the supporting portion is viewed in plan, and Lt is a maximum length of the protruding portion in a direction parallel to a central axis of the protruding portion.

Advantageous Effects of Invention

The above ventilation component is advantageous in preventing breakage of the ventilation component at the time of inserting the ventilation component at a slant angle to an axis of the opening of the housing.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description describes examples of the present invention, and the present invention is not limited to the following embodiments.

As shown inFIGS.1and2, the ventilation component1is configured to be attached to an edge2fof an opening21of a housing2, the opening21communicating an internal space2uand an outer space2sof the housing2. The ventilation component1includes a ventilation path10. The ventilation path10is a path for allowing ventilation between the internal space2uand the outer space2swhen the ventilation component1is attached to the edge2f. The ventilation component1includes a supporting portion12, a gas-permeable membrane11, a protruding portion13, and a sealing member14. The supporting portion12surrounds the ventilation path10. The gas-permeable membrane11is bonded to the supporting portion12and closes the ventilation path10in a ventilatable manner. The protruding portion13is a part having a tubular shape, the part being arranged to protrude from the supporting portion12and surround one end of the ventilation path10, the part being configured to be in contact with the edge2fwhen the ventilation component1is attached to the edge2f. The sealing member14is disposed around the protruding portion13, and seals a gap between an outer surface2gof the housing2and the ventilation component1when the ventilation component1is attached to the edge2f. The ventilation component1satisfies requirements 2.5≤Gs/Gt≤5.0 and 1.0≤ {(Gs-Gt)/2}/Lt≤3.0. As shown inFIG.3A, Gt is a maximum outer diameter of the protruding portion13in a boundary between the protruding portion13and the supporting portion12. Gs is a maximum outer diameter of an outer surface12gof the supporting portion12in contact with the protruding portion13, the maximum outer diameter being defined when the outer surface12gof the supporting portion12is viewed in plan from the protruding portion13side. Lt is a maximum length of the protruding portion13in a direction parallel to a central axis of the protruding portion13.

As shown inFIG.1, the protruding portion13is inserted into the opening21to attach the ventilation component1to the housing2. When inserted, the protruding portion13comes in contact with the edge2fof the opening21and is deformed inward. It is most desirable in view of preventing breakage of the protruding portion13that to attach the ventilation component1to the housing2, the protruding portion13be inserted into the opening21such that the protruding portion13moves in parallel to an axis A1of the opening21. According to a study by the present inventors, however, it is sometimes difficult to move a ventilation component in parallel to an axis of an opening of a housing to insert the ventilation component into the opening of the housing. For example, because of design specifications of the housing2, manual execution of attachment of a ventilation component to a housing, or other circumstances, it is sometimes difficult to move a ventilation component in parallel to an axis of an opening of a housing to insert the ventilation component into the opening of the housing. For example, it is sometimes difficult to automate attachment of a ventilation component to a housing of a particular device, and attachment thereto needs to be executed manually.

Therefore, the present inventors made intensive studies to discover a technique for preventing breakage of a ventilation component even in the case where the ventilation component is inserted into an opening at a slant angle to an axis of an opening of a housing. Through much trial and error, the present inventors have found that as described above, the ventilation component1satisfying the requirements 2.5≤Gs/Gt≤5.0 and 1.0≤{(Gs−Gt)/2}/Lt≤3.0 is advantageous in preventing breakage of the ventilation component1at the time of inserting the protruding portion13into the opening21with the ventilation component1at a slant angle to the axis A1.

As shown inFIG.4, when the protruding portion13is inserted into the opening21with the ventilation component1at a slant angle to the axis A1, an end of the protruding portion13comes into contact with the edge2f. The ventilation component1satisfying the requirements 2.5≤Gs/Gt and 1.0≤{(Gs−Gt)/2}/Lt is likely to make a small inclination angle with the axis A1when the outer surface12gof the supporting portion12is in contact with the outer surface2gof the housing2. Additionally, when the ventilation component1is pushed toward the internal space2uof the housing2with the protruding portion13and the outer surface2gof the housing2in contact with each other, a moment acting on a contact area of the protruding portion13with a fulcrum thereof at a root of the protruding portion13is likely to be small, the contact area being in contact with the outer surface2g. Consequently, outward deformation of the protruding portion13is reduced and breakage of the ventilation component1is easily prevented.

Since the requirement Gs/Gt≤5.0 is satisfied, the distance between a peripheral edge of the outer surface12gof the supporting portion12and the opening21is likely to be small, and the housing2to which the ventilation component1is to be attached is less strictly limited. Since the requirement {(Gs−Gt)/2}/Lt≤3.0 is satisfied, the maximum length Lt of the protruding portion13is likely to be short, a dimension of the sealing member14in the direction parallel to the central axis of the protruding portion13can be reduced, and the cost of manufacturing the ventilation component1can be reduced.

The ratio Gs/Gt is desirably 2.6 or more and more desirably 2.8 or more. The ratio Gs/Gt is desirably 4.5 or less and more desirably 4.0 or less.

The value of {(Gs−Gt)/2}/Lt is desirably 1.2 or more and more desirably 1.4 or more. The value of {(Gs−Gt)/2}/Lt is desirably 2.5 or less and more desirably 2.0 or less.

As shown inFIG.2, the protruding portion13includes a plurality of leg portions13a. The plurality of leg portions13aare disposed around the central axis of the protruding portion13and spaced from each other by a slit13sextending from the end of the protruding portion13along the central axis of the protruding portion13. At least one of the plurality of leg portions13aincludes an engaging portion13kcapable of being engaged with the housing2. The engaging portion13kprotrudes outward in a direction perpendicular to the central axis of the protruding portion13. According to this configuration, in a procedure, including insertion of the protruding portion13into the opening21, for attaching the ventilation component1to the housing2, the leg portion13aelastically deforms inward when an end portion of the protruding portion13comes into contact with the edge2f. Then, the deformed leg portion13areturns to its original form when the engaging portion13kpasses through the opening21, and the engaging portion13k, for example, comes into contact with an inner surface of the housing2. In this manner, the engaging portion13kis engaged with the housing2by snap-fitting and the ventilation component1is attached to the edge2fof the housing2.

As shown inFIG.3A, the protruding portion13includes, for example, a flat or curved bottom face13bat the end portion of the protruding portion13. As shown inFIG.3B, a ring-shaped figure G is defined by the bottom face13bwhen the bottom face13bis viewed in plan. The figure G may be, for example, an annular figure or a plurality of curved-belt-shaped figures disposed along an annular ring at given intervals. In the ventilation component1, a ratio Gs/Gr is, for example, 2.5 or more and 5.0 or less. Gr is a maximum outer diameter of the ring-shaped figure G. According to this configuration, when the protruding portion13is inserted into the opening21with the ventilation component1at a slant angle to the axis A1, outward deformation of the protruding portion13is more reliably reduced and breakage of the ventilation component1is easily prevented.

As shown inFIG.3C, when a part of the bottom face13bcorresponding to an outermost part of the figure G is formed of a flat face, the maximum outer diameter of the figure G is defined by an outer edge E of the flat face. As shown inFIG.3D, when the part of the bottom face13bcorresponding to the outermost part of the figure G is formed of a curved face, in a cross-section along a plane including the central axis of the protruding portion13, the maximum outer diameter of the figure G is defined by a boundary B between the curved face and an outline that is positioned outside of the curved face and whose curvature can be considered 0.

The ratio Gs/Gr is desirably 2.6 or more and more desirably 2.8 or more. The ratio Gs/Gr is desirably 4.5 or less and more desirably 4.0 or less.

The supporting portion12and the protruding portion13may be an integrally-molded component or may be components separately produced. The materials of the supporting portion12and the protruding portion13are, for example, a thermoplastic resin in view of moldability. Examples of the thermoplastic resin can include polyamides (PA), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polycarbonate (PC), polypropylene (PP), polyphenylene ether (PPE), and thermoplastic elastomers. The materials of the supporting portion12and the protruding portion13may be a thermosetting resin or a metal. The materials of the supporting portion12and the protruding portion13may be a rubber. Examples of the rubber include nitrile-butadiene rubber (NBR), ethylene propylene rubber (EPDM), silicone rubbers, fluorine rubbers, acrylic rubbers, and hydrogenated nitrile rubbers.

As shown inFIG.2, the supporting portion12typically includes an adherend surface12bto which the gas-permeable membrane11is attached. The adherend surface12bis, for example, a ring-shaped surface. The gas-permeable membrane11is disposed, for example, along the direction perpendicular to the central axis of the protruding portion13.

In the ventilation component1, a ratio Nt/Gt is, for example, 2.0 or more and 8.0 or less. As shown inFIG.3A, Nt is a maximum inner diameter of the ventilation path10, the maximum inner diameter being defined at a position in contact with a surface of the gas-permeable membrane11, the surface being configured to face the inner space2uwhen the ventilation component1is attached to the edge2f. According to this configuration, the maximum inner diameter Nt of the ventilation path10is likely to be large. That is advantageous in view of increasing the amount of gas permeating through the ventilation component1.

The ratio Nt/Gt is desirably 2.5 or more and more desirably 3.0 or more. The ratio Nt/Gt is desirably 7.0 or less and more desirably 6.0 or less.

The gas-permeable membrane11is not limited to a particular gas-permeable membrane as long as the gas-permeable membrane11has desirable gas permeability. The gas-permeable membrane11may be a single layer membrane, or may be a multilayer membrane. In the case where the gas-permeable membrane11is a multilayer membrane, each layer thereof can be one selected from the group consisting of a porous membrane, a nonwoven fabric, a cloth, and a mesh. The gas-permeable membrane11may include: a porous membrane and a nonwoven fabric; a porous membrane and at least one of a cloth and a mesh; or a plurality of nonwoven fabrics. Typically, the gas-permeable membrane11is composed of an organic polymer material (resin). The material of the porous membrane is, for example, a fluorine resin. As the fluorine resin can be used, for example, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, a tetrafluoroethylene-hexafluoropropylene copolymer, or a tetrafluoroethylene-ethylene copolymer. The material of the porous membrane may be a polyolefin, such as a homopolymer or copolymer of a monomer(s) such as ethylene, propylene, or 4-methylpentene-1,1-butene. The porous membrane may be a porous nanofiber membrane made of, for example, polyacrylonitrile, nylon, or polylactic acid. The porous membrane can be manufactured by a known drawing or extraction technique. Examples of the materials of the nonwoven fabric, the cloth, and the mesh include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, nylon, aramids, and ethylene-vinyl acetate copolymer.

The gas-permeable membrane11desirably includes a PTFE porous membrane. The PTFE porous membrane can ensure gas permeability with a small area and can effectively prevent entry of foreign matters. The PTFE porous membrane may be layered on a gas-permeable supporting member such as a nonwoven fabric.

The gas-permeable membrane11may be subject to a liquid-repellant treatment as necessary. The liquid-repellant treatment is performed, for example, by forming a liquid-repellant coating film containing a fluorine surface modifier having a perfluoroalkyl group on the gas-permeable membrane11. The method for forming the liquid-repellant coating film is not limited to a particular formation method. The liquid-repellant coating film is formed, for example, by coating a porous resin membrane with a solution or dispersion of a fluorine surface modifier having a perfluoroalkyl group by a method such as air spraying, electrostatic spraying, dip coating, spin coating, roll coating, curtain flow coating, or impregnation. The liquid-repellant coating film may be formed by electrodeposition or plasma polymerization.

The gas-permeable membrane11is, for example, adhered to the adherend surface12b. The gas-permeable membrane11may be welded to the adherend surface12b. The available welding method can be thermal welding, ultrasonic welding, and laser welding. Alternately, at the time of molding the supporting portion12, the gas-permeable membrane11may be attached to the adherend surface12bby insert molding, specifically, by pouring a resin in a mold for molding the supporting portion12with the gas-permeable membrane11disposed at a given position in the mold. The gas-permeable membrane11may be attached to the adherend surface12bwith a double-sided adhesive tape.

The sealing member14is not limited to a particular sealing member as long as the sealing member14has desirable sealability. In a state where the ventilation component1is not attached to the housing2, a cross-section of the sealing member14cut along a plane including an axis of the sealing member14is, for example, a circular plane, an elliptical plane, or a plane having a corner. The plane having a corner may be a polygon or a figure composed of a combination of a curved line and a straight line. The sealing member14may have a hollow structure having a ring-shaped inner space.

The material of the sealing member14is not limited to a particular material as long as the sealing member14can exhibit desirable sealability. For example, any of the materials described above as examples of the materials of the supporting portion12and the protruding portion13can be used as the material of the sealing member14. The sealing member14is typically an elastic body that is elastically deformable, and the material of the sealing member14can be an elastomer such as a natural rubber, a synthetic rubber, or a thermoplastic elastomer.

As shown inFIG.2, the ventilation component1further includes, for example, a cover16. The cover16is coupled to the supporting portion12. The cover16covers the gas-permeable membrane11and forms, between the gas-permeable membrane11and the cover16, a space17scommunicating with an outer space of the ventilation component1. The space17sforms part of the ventilation path10. Owing to the cover16, the gas-permeable membrane11is protected appropriately.

The cover16may be a component integrally molded with the supporting portion12or may be a component produced separately from the supporting portion12. Any of the materials described as examples of the material of the supporting portion12can be used, for example, as the material of the cover16.

At least either of the supporting portion12and the cover16may have a side wall disposed at an outer perimeter of the space17s. The side wall can include a plurality of side walls separately disposed in a perimeter direction of the space17sat given intervals. The supporting portion12and the cover16each may have a plurality of side walls separately disposed in the perimeter direction at given intervals. In that case, the side walls of the supporting portion12and the side walls of the cover16may partially overlap in the perimeter direction.

As shown inFIG.2, a ventilation structure50can be provided by attaching the ventilation component1to the edge2fof the opening21of the housing2. In the ventilation structure50, the housing2is, for example, a housing of an electronic device. Examples of the electronic device include automotive electronic devices, such as vehicle lamps, electronic control units (ECUs), electric power systems (EPSs), battery packs, inverters, converters, millimeter-wave radars, and vehicle-mounted cameras. The electronic device may be one used in applications other than use for automobiles. In the ventilation structure50, the ventilation path10can eliminate a pressure difference occurring between the internal space2uand the outer space2sof the housing2due to a temperature variation. Moreover, since the gas-permeable membrane11closes the ventilation path10in a ventilatable manner, entry of foreign matters into the internal space2ucan be prevented and, for example, the ventilation structure50has dust proofness. Furthermore, the ventilation structure50can prevent entry of water, oil, salt, etc. into the internal space2u.