Casing venting device for electromagnetic compatibility

Abstract

This venting device (1) is configured to be positioned across an opening (5) formed in the wall (7) of a metal housing (3), said device (1) forming a conduit (13) passing through said wall (7) and comprising a membrane (15) filtering the air, impermeable to water and dust, positioned across said conduit (13), the device (1) comprising a metal portion (31) aligned with the opening (5) and having transverse dimensions equivalent to the transverse dimensions of said opening (5), said metal portion (31) being electrically connected to the housing (3). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Casing venting device for electromagnetic compatibility technical field

[0001] The present invention relates to the protection of electronic equipment from electromagnetic waves incident on said electronic equipment.

[0002] In particular, the present invention relates to the protection of electronic equipment embedded in a vehicle casing, such as that of a motor vehicle. Prior art

[0003] In an electronic equipment housing of a motor vehicle, said electronic equipment produces heat and it is necessary to dissipate it to cool the interior and prevent overheating of said electronic equipment.

[0004] For this purpose, an opening is formed in a wall of the housing, the opening being closed by a venting device containing a conduit allowing air to pass in both directions, from the outside of the housing to the inside, and from the inside of the housing to the outside.

[0005] The device generally includes a membrane passing through the conduit and allowing the passage of air but not that of water or dust in order to preserve a clean environment in the casing.

[0006] However, the opening formed in the housing allows electromagnetic waves generated outside the housing to pass through, which can disrupt the electronic equipment in the housing. Description of the invention

[0007] The present invention therefore aims to overcome the aforementioned drawback and to provide a device for venting the casing preventing external electromagnetic waves from interfering with the electronic equipment present in the casing.

[0008] The present invention relates to a venting device configured to be positioned across an orifice formed in the wall of a metal casing, said device forming a conduit through said wall and comprising an air-filtering membrane impermeable to water and dust positioned across said conduit, the device further comprising a metallic part aligned with the orifice and of transverse dimensions equivalent to the transverse dimensions of said orifice, said metallic part being electrically connected to the casing.

[0009] Thus, the metallic part covers the opening and forms a barrier that stops electromagnetic waves that could have penetrated the housing through the opening. Furthermore, the electrical continuity formed between the electrical part and the housing allows for The electrical continuity diffuses the waves received by the metallic part throughout the entire casing. For example, if the metallic part heats up upon receiving electromagnetic waves, the heat will also be transmitted and dissipated throughout the entire casing. More generally, electrical continuity creates a wave trap and prevents the formation of electrical arcs.

[0010] Advantageously, the device includes a valve configured to be positioned across the orifice and forming the conduit, the valve including a means for fixing said valve to the wall of the housing, the membrane being fixed to said valve.

[0011] Preferably, the metal part comprises a sheet metal configured to wrap the valve on one side of the housing wall, the sheet metal preferably being made of the same metal as the housing metal, the sheet metal comprising at least one opening positioned transversely with respect to the axial direction of the orifice and configured to allow the passage of air through the sheet metal to the duct.

[0012] In a particular embodiment, the area corresponding to the sum of the sections of all the openings is equal, to within 50%, to the section of the duct.

[0013] Advantageously, the sheet metal comprises at least three equidistant openings, the sheet metal comprising a clip extending into each opening, each clip being configured to fix the sheet metal to the flap.

[0014] In one embodiment, the sheet metal includes at least one claw configured to extend from the sheet metal towards the housing so as to form an electrical contact with said housing.

[0015] Advantageously, the sheet metal includes an end configured to be positioned between the valve and the housing so as to form an electrical contact with said housing.

[0016] In one embodiment, the valve mainly comprises metal and / or a plastic material.

[0017] Advantageously, the membrane has a water impermeability index greater than 1500 Schmerber.

[0018] The present invention also relates to a metal casing comprising a wall in which an orifice is formed, the casing further comprising the venting device as defined above and intended to be positioned across said orifice. Brief description of the drawings

[0019] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0020] [Fig.1] is a schematic cross-sectional view of a first embodiment of a crankcase venting device according to the invention;

[0021] [Fig.2] is a schematic perspective view of the device according to [Fig. 1]; and

[0022] [Fig.3] is a schematic cross-sectional view of a second embodiment of a crankcase venting device according to the invention.

[0023] Detailed description of at least one embodiment

[0024] A schematic cross-sectional view of a first embodiment of a device 1 for venting a housing 3 has been shown in [Fig.1].

[0025] The housing 3 is in particular a metal housing 3, for example made of aluminium, and contains electronic equipment.

[0026] We have also schematically and in perspective represented on [Fig.2] the same first embodiment of the venting device 1.

[0027] Said device 1 is configured to be positioned across an orifice 5 formed in the wall 7 of the housing 3. The orifice 5 allows in particular to allow air to circulate between the outside 9 and the inside 11 of the housing 3 in order to avoid any overheating of the electronic equipment contained in said housing 3.

[0028] The device 1 forms a conduit 13 passing through said wall 7 and includes a membrane 15 filtering the air. The air entering the housing 3 is therefore not polluted by unwanted particles.

[0029] In particular, the membrane 15 is impermeable to water and dust and is positioned totally across said conduit 13.

[0030] More specifically, the membrane 15 has a water impermeability index greater than 1500 Schmerber.

[0031] The membrane 15 is for example made of a material comprising stretched polytetrafluoroethylene.

[0032] Advantageously, the device 1 includes a valve 17 configured to be positioned across the orifice 5 and forming the conduit 13, the membrane 15 being fixed to said valve 17.

[0033] In particular, the valve 17 may include an external element 19 intended to face the outside 9 of the housing 3, and an internal element 21 intended to be introduced into the orifice 5 and forming the conduit 13. The diaphragm 15 is, for example, fixed to the valve 17 by being clamped between the external element 19 and the internal element 21. The diaphragm 15 may furthermore be, for example, glued or welded, for example by ultrasound, to the valve 17.

[0034] The external element 19 protects the membrane 15 from the external environment 9.

[0035] The external element 19 is connected to the internal element 21 by a fastening system 23, such as a clip or glue or by ultrasonic welding, a space 25 between the external element 19 and the membrane 15 as well as the internal element 21 being left free so as to allow the passage of air from the outside 9 of the housing 3 to the duct 13 in the center of the internal element 21. The space 25 opens perpendicularly to the axial direction of the orifice 5, or transversely to the axial direction of the orifice 5. The axial, or longitudinal, direction of the orifice 5 is in particular perpendicular to the surface of the wall 7 of the housing 3.

[0036] The valve 17 includes a means for fixing said valve 17 to the wall 7 of the housing 3. The fixing means 27 may be clips, as shown in [Fig.1], or a bayonet system.

[0037] The device 1 also includes an O-ring 29 positioned between the housing 3 and the valve 17, in particular the internal element 21, in order to seal the orifice 5. The only access of air to the inside 11 of the housing 3 is therefore by passing through the membrane 15.

[0038] The device 1 further comprises a metallic part 31 aligned with the orifice 5 and having transverse dimensions equivalent to the transverse dimensions of said orifice 5. "Aligned" means that the metallic part is positioned opposite the orifice, although potentially separated by other elements. In particular, the central axis of the metallic part is aligned with the longitudinal axis of the orifice. Thus, the metallic part 31 covers the orifice 5 and forms a barrier stopping electromagnetic waves that could have entered the housing 3 through the orifice 5.

[0039] Furthermore, said metallic part 31 is electrically connected to the housing 3 so as to diffuse the waves received by the metallic part 31 throughout the housing 3.

[0040] In an embodiment not shown, the metal part 31 can be the valve 17 itself, made of metal, for example of aluminium, steel, or even galvanized copper.

[0041] Alternatively, only the external element 19 comprises the metal part 31. In this case, the rest of the valve 17 can be made of plastic material, such as polypropylene or polyamide, and includes, for example, fiberglass.

[0042] In the embodiment shown in Figures 1 and 2, the metal part 31 is separate from the valve 17 and includes a sheet metal 33 configured to wrap the valve 17 on one side of the wall 7 of the housing 3, in particular on the outside 9 of the housing 3.

[0043] The sheet metal 33 is preferably made of the same metal as the housing 3, for example aluminum, or even galvanized steel or copper. The valve 17 can then understand mainly a plastic material such as polypropylene or polyamide, and optionally includes fiberglass.

[0044] The sheet metal 33 comprising at least one opening 35 positioned transversely with respect to the axial direction of the orifice 5 and configured to allow the passage of air through the sheet metal 33 towards the conduit 13. In particular, each opening 35 gives access to the space made between the external element 19 and the membrane 15.

[0045] In a particular embodiment, the area corresponding to the sum of the sections of all the openings 35 is equal, to within 50%, to the section of the conduit 13, thus allowing a less turbulent flow.

[0046] Advantageously, the sheet 33 comprises at least three equidistant openings 35, for example at 120° to each other with respect to the center of the sheet 33, in other words the intersection between the central and longitudinal axis of the orifice 5 and the sheet 33.

[0047] The sheet metal 33 includes, for example, a clip 37, taking the form of an outgrowth, extending into each opening, each clip 37 being configured to fix the sheet metal 33 to the flap 17. To do this, the clip 37 can, for example, bear against the external element 19 of the flap 17 in its fixed position.

[0048] Furthermore, the sheet metal 33 includes at least one claw 39 configured to extend from the sheet metal 33 towards the housing 3 so as to form an electrical contact with said housing 3. As shown in Figures 1 and 2, a set of claws 39 extends from the sheet metal 33 towards the housing 3.

[0049] One of the advantages of the first embodiment presented is the possibility of positioning or replacing a sheet 33 on an existing valve 17, without needing to modify the valve 17. Installation of the sheet 33 in after-sales service is therefore possible.

[0050] A schematic cross-sectional view of a second embodiment of the venting device 1 is shown in [Fig.3].

[0051] This second embodiment is similar to the first embodiment described in Figures 1 and 2, except for the absence of a clip 37 in each opening 35. In this embodiment, the sheet metal 33 includes an end 41 configured to be positioned between the valve 17 and the housing 3, for example by folding, so as to form an electrical contact with said housing 3. This end 41 also serves to keep the sheet metal 33 fixed to the valve 17. This second embodiment nevertheless requires a gap to be provided between the valve 17 and the housing 3 in order to accommodate the sheet metal 33.

Claims

Demands

1. A venting device (1) configured to be positioned across an orifice (5) formed in the wall (7) of a metal housing (3), said device (1) forming a conduit (13) through said wall (7) and comprising a membrane (15) filtering air impermeable to water and dust positioned across said conduit (13), characterized in that it comprises a metallic part (31) aligned with the orifice (5) and of transverse dimensions equivalent to the transverse dimensions of said orifice (5), said metallic part (31) being electrically connected to the housing (3).

2. Device (1) according to claim 1, comprising a valve (17) configured to be positioned across the orifice (5) and forming the conduit (13), the valve (17) comprising a means for fixing said valve (17) to the wall (7) of the housing (3), the membrane (15) being fixed to said valve (17).

3. Device (1) according to claim 2, wherein the metal part (31) comprises a sheet (33) configured to wrap the valve (17) on one side of the wall (7) of the housing (3), the sheet (33) preferably being made of a metal identical to the metal of the housing (3), the sheet (33) comprising at least one opening (35) positioned transversely with respect to the axial direction of the orifice (5) and configured to allow the passage of air through the sheet (33) into the conduit (13).

4. Device (1) according to claim 3, wherein the area corresponding to the sum of the sections of all the openings (35) is equal, to within 50%, to the section of the conduit (13).

5. Device (1) according to any one of claims 3 and 4, wherein the sheet metal (33) comprises at least three equidistant openings (35), the sheet metal (33) comprising a clip (37) extending into each opening (35), each clip (37) being configured to fix the sheet metal (33) to the flap (17).

6. Device (1) according to any one of claims 3 to 5, wherein the sheet metal (33) comprises at least one claw (39) configured to extend from the sheet metal (33) to the housing (3) so as to form an electrical contact with said housing (3).

7. Device (1) according to any one of claims 3 to 6, wherein the sheet metal (33) comprises an end (41) configured to be positioned between the valve (17) and the housing (3) so as to form an electrical contact with said housing (3).

8. Device (1) according to any one of claims 2 to 7, wherein the valve (17) comprises mainly metal and / or plastic.

9. Device (1) according to any one of claims 1 to 8, wherein the membrane (15) has a water impermeability index greater than 1500 Schmerber.

10. Metal housing (3) comprising a wall (7) in which an orifice (5) is formed, the housing (3) further comprising the venting device (1) according to any one of claims 1 to 9 intended to be positioned across said orifice (5).

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