Device for pressure compensation in a housing

Abstract

The invention relates to a device (1) for pressure compensation in a housing (2), comprising: a first surface (3); a second surface (4), wherein the second surface (4) is arranged facing away from the first surface (3); an opening (5), wherein the opening (5) extends from the first surface (3) to the second surface (4); a gas-permeable membrane (6), which closes the opening (5) in a fluid-tight manner in the region of the first surface (3); and a cover (7), which is arranged in the region of the second surface (4) and covers at least a central region of the opening (5) when viewed in the perpendicular direction to the second surface (4).

Description

[0001] Device for pressure equalization in a housing

[0002] The invention relates to a device for pressure equalization in a housing. Furthermore, the invention relates to a housing with a device for pressure equalization.

[0003] Many enclosures that protect electronic components from environmental influences incorporate a pressure equalization element. This is necessary to maintain pressure equilibrium between the inside of the enclosure and the surrounding environment when temperatures differ. Without a pressure equalization element, sealing elements can be overstressed by pressure differentials, and there is a risk that moisture and liquids from the environment could enter the enclosure if there is negative pressure.

[0004] Moisture and liquids inside the housing inevitably lead to malfunctions or failure of the electronic components inside the housing.

[0005] One requirement for enclosures is dust and water resistance according to IP6K9K (ISO 20653 and DIN EN 60529). A pressure equalization element often used for this purpose consists of a membrane that is waterproof but gas-permeable. Protection against damage to the membrane from liquids during high-pressure or steam jet cleaning is important, especially when the pressure equalization element is used in enclosures for road vehicles.

[0006] Another common requirement for the housing is to pass an immersion test. In this test, a heated housing is immersed in a cold liquid and then stored at a high temperature. This immersion test specifically targets sealing elements, including the diaphragm, and is designed to test their robustness. During such a test, the liquid, for example, water, must be able to drain from the pressure equalization element so that pressure equilibrium can be established. This means that the diaphragm's breathability must be ensured. If the liquid, for example, water, cannot drain, it will evaporate in the area in front of or on the pressure equalization element when it warms up after immersion. The water vapor can then pass through the gas-permeable diaphragm of the pressure equalization element and into the interior of the housing.There, the hot water vapor meets colder surfaces, and condensate, such as condensation water, forms. This condensate can subsequently lead to corrosion. The invention therefore aims to provide a pressure equalization device within a housing that ensures reliable pressure equalization and a tight seal against liquids, while also being robust against mechanical impacts from liquids or objects.

[0007] The problems are solved by a pressure equalization device according to the invention comprising:

[0008] - a first surface;

[0009] - a second surface, wherein the second surface is arranged facing away from the first surface;

[0010] - an opening, wherein the opening extends from the first surface to the second surface;

[0011] - a gas-permeable membrane that seals the opening in the area of ​​the first surface in a liquid-tight manner; and

[0012] - a cover which is located in the area of ​​the second surface and, when viewed in the normal direction to the second surface, covers at least a central area of ​​the opening.

[0013] These features ensure optimal pressure equalization between the pressure at the first surface and the pressure at the second surface. The cover protects the membrane from damage caused by mechanical impacts, such as objects or liquids, particularly during high-pressure or steam jet cleaning (9K according to ISO 20653 and DIN EN 60529). These features also prevent liquid or moisture from penetrating the opening and thus reaching the membrane.In particular, the feature that the membrane seals the opening in the area of ​​the first surface in a liquid-tight manner creates a space between the membrane and the cover in which any liquid droplets present can collect, leading to improved drainage of the liquid, especially under the influence of gravity. This is achieved particularly advantageously when the device is spatially arranged such that at least one longitudinal axis of the opening lies in the horizontal plane, or, advantageously, when the longitudinal axis is inclined relative to the horizontal plane towards the second surface. This can be taken into account during installation or use of the device. The device is thus IP6k9k compliant and suitable for immersion testing. It is advantageous if the cover is arranged perpendicular to the second surface at a certain distance from the opening.

[0014] This feature facilitates the drainage of liquid from the opening while simultaneously protecting the membrane. Viewed perpendicular to the second surface, the visible area of ​​the membrane remains the same; however, the initial gap creates a passage for improved liquid drainage. This design also allows for the inclusion of a cover that essentially completely obscures the opening when viewed perpendicular to the second surface, while still permitting liquid drainage.

[0015] It is advantageous if the device further comprises a border, wherein the border:

[0016] - is located on the second surface and protrudes from the second surface;

[0017] - the opening and the cover at least partially surround, and

[0018] - shows a break.

[0019] These features achieve several advantageous technical effects. The rim prevents liquid on the second surface from flowing into the opening, allowing it to drain around the opening. Furthermore, the opening, and thus the membrane in particular, is laterally shielded against mechanical impacts from objects or liquids. This also provides protection against mechanical impacts on the cover. The interruption advantageously allows liquid to drain from the area enclosed by the rim and from the opening through the interruption. This is achieved particularly advantageously when the device is spatially arranged such that an imaginary arrow pointing from the cover to the interruption essentially points in the direction of gravity. This can be taken into account during installation or use of the device.

[0020] It is advantageous if the border includes end pieces, each of which is arranged starting from the interruption along the second surface and running away from the opening.

[0021] These features facilitate the drainage of liquid through the interruption while simultaneously preventing liquid from entering the opening through the interruption, for example, via a lateral inlet. It is advantageous if the cover has an extension that points essentially parallel to the second surface and towards the interruption.

[0022] This feature further improves the flow of liquid. The extension can be shaped in such a way that, when viewed perpendicular to the second surface, the cover with the extension has a droplet shape. Furthermore, the extension provides additional protection for the membrane against mechanical impacts that could affect the membrane from the interruption.

[0023] It is advantageous if the border protrudes further from the second surface in a normal direction than the cover.

[0024] This feature further improves the protection against mechanical impacts on the membrane and especially the cover.

[0025] It is advantageous if the opening, the cover, the first gap, any rim and / or any interruption is dimensioned to allow for a substantially complete drainage of the liquid, taking into account capillary action and / or surface tension of a liquid, especially water.

[0026] The dimensions are based on the assumption that the liquid, or the quantity of liquid droplets, that can accumulate in front of the membrane is heavy enough and cannot adhere to any other geometry of the device via capillary action, allowing the liquid or the quantity of liquid droplets to detach from the membrane and drain away due to gravity. The dimensions specifically concern the diameter, depth, and shape of the opening; the initial distance of the cover from the second surface; the shape and diameter of the cover; the shape and height of the rim; the initial distance of the rim from the opening; the width of the interruption; and the length of the end pieces. In particular, edges of the device may also be rounded to further facilitate the drainage of the liquid.Cylindrical openings or openings in the shape of a truncated cone have proven advantageous, the latter having a larger diameter in the area of ​​the second surface than in the area of ​​the first surface. It is particularly advantageous if the device, excluding the membrane, is formed in one piece.

[0027] This measure reduces the susceptibility to errors, particularly leaks that can occur when joining individual parts, and enables cost-effective and simple manufacturing. The device can thus be manufactured entirely by injection molding or 3D printing from materials such as plastic or aluminum.

[0028] The problems are also solved by a housing according to the invention, in particular for electronic components, with a device for pressure equalization, wherein the device is integrated into the housing in such a way that pressure equalization in the housing is made possible by the device.

[0029] The housing can have an outer and an inner surface, and the device can be integrated into the housing in such a way that the first surface of the device forms part of the inner surface of the housing and the second surface of the device forms part of the outer surface of the housing. The device prevents mechanical stress on any seals in or on the housing. It also prevents the ingress of liquid or moisture into the housing.

[0030] It is particularly advantageous if the housing and the device are formed in one piece.

[0031] This measure further reduces the potential for errors, as, for example, no seals are required between the device and the housing. It also simplifies and reduces manufacturing costs.

[0032] The invention will now be described and explained in more detail with reference to the exemplary embodiments shown in the figures.

[0033] They show, for example:

[0034] Fig. 1: A top view of an exemplary first embodiment of a device according to the invention, Fig. 2: A sectional view of an exemplary first embodiment of a device according to the invention,

[0035] Fig. 3: A sectional view in perspective of an exemplary first embodiment of a device according to the invention,

[0036] Fig. 4: A perspective view of an exemplary second embodiment of a device according to the invention,

[0037] Fig. 5: A perspective view of an exemplary third embodiment of a device according to the invention,

[0038] Fig. 6: A perspective view of an exemplary fourth embodiment of a device according to the invention,

[0039] Fig. 7: A perspective view of an exemplary fifth embodiment of a device according to the invention, and

[0040] Fig. 8: A perspective view of an exemplary sixth embodiment of a device according to the invention.

[0041] Fig. 1 shows a top view of an exemplary first embodiment of a device according to the invention. The device 1 is integrally formed with a housing 2. The device 1 comprises a first surface 3 (not shown), a second surface 4, an opening 5, a gas-permeable membrane 6, and a cover 7. The membrane is dustproof and liquid-tight, in particular waterproof. The second surface 4 is arranged facing away from the first surface 3. In this embodiment, the second surface 4 has, for example, a mean roughness Ra of less than or equal to 3.2. This facilitates the flow of liquid. The opening 5 extends from the first surface 3 to the second surface 4. In this embodiment, the opening 5 has a cylindrical shape. The gas-permeable membrane 6 seals the opening 5 in the region of the first surface 3 in a liquid-tight manner.The membrane 6 is semipermeable, meaning it is gas-permeable but liquid-tight and dust-tight. The membrane 6 is located in the region of the first surface 3. In this embodiment, the membrane 6 is positioned on the first surface 3. It can be attached to the first surface by various means, for example, it can be glued or clamped. The cover 7 is located in the region of the second surface 4 and, viewed in the normal direction to the second surface 4, covers at least a central area of ​​the opening 5. In this embodiment, the cover 7 is positioned in the normal direction to the second surface 4 at a first distance A from the opening 5. The first distance A is the distance in the normal direction to the second surface 4 between a side of the cover 7 facing the second surface 4 and the second surface 4.In this embodiment, the device 1 further comprises a rim 8. The rim 8 is arranged on the second surface 4 and projects from the second surface 4. The rim 8 at least partially surrounds the opening 5 and the cover 7. The rim has a break 9. In this embodiment, the rim 8 comprises end pieces 10, each of which extends from the break 9 along the second surface 4 away from the opening 5. In this embodiment, the rim 8 comprises two end pieces 10. These end pieces 10 each begin at the point where the rim 8 is interrupted by the break 9 and end at a point on the second surface 4 further away from the opening. In this embodiment, the rim 8 essentially has the form of a broken ring.In this embodiment, the cover 7 has an extension 11 that extends the cover 7 and is arranged essentially parallel to the second surface 4, pointing towards the interruption 9. In this embodiment, the cover 7 is connected to the second surface 4 via the extension 11. Viewed in the normal direction to the second surface, the cover 7 with the extension 11 is essentially teardrop-shaped. In this embodiment, the perimeter 8 projects further from the second surface 4 in a normal direction than the cover 7. It is further shown that in this embodiment, the cover 7 is connected to the perimeter 8 and / or the second surface 4 by a connecting section 12. According to the invention, the cover 7 can be connected to the perimeter 8 and / or the second surface 4 by further connecting sections 12.In this embodiment, the device 1, in particular the opening 5, the cover 7, the first gap A, the second gap B, the third gap C, the rim 8 and / or the interruption 9, is dimensioned to allow for a substantially complete drainage of the liquid, especially water, with regard to capillary action and / or surface tension. It has been found that a first gap A of between 1 mm and 3 mm, in particular between 1.3 mm and 1.5 mm, and most preferably 1.4 mm, is advantageous. It has also been found that a second gap B between an inner surface of the rim and an outer edge of the cover of between 1 mm and 3 mm, in particular between 1.2 mm and 1.4 mm, and most preferably 1.3 mm, is advantageous.It has further been shown that a third distance C between an edge of the opening 5, which is closest to the interruption 9, and an end of the end pieces 10 located away from the interruption, between 3 mm and 10 mm, in particular between 6.5 mm and 7.5 mm, and most preferably 7 mm, is advantageous. This geometry prevents the accumulation of liquid and, if necessary, ensures the drainage of liquid. In this embodiment, the device 1, with the exception of the diaphragm 6, is formed in one piece. In this embodiment, the device 1 is integrated into a housing 2. The device 1 is integrated into the housing 2 in such a way that pressure equalization within the housing 2 is enabled by the device 1. The device 1 and the housing 2 are formed in one piece.The device 1 is arranged in the housing 2 such that, when the housing 2 is used in a specific installation position, the opening 9 is oriented in such a way that any liquid potentially present in the opening 5 can drain through the opening 9 due to gravity. This ensures that the membrane 6 is free of liquid or moisture and can equalize the pressure.

[0042] Fig. 2 shows a sectional view of an exemplary first embodiment of a device according to the invention. The first distance A, with which the cover 7 is arranged in the normal direction to the second surface 4 and the opening 5, is shown in particular. Also shown is the height F of the rim 8, with which the rim 8 projects from the second surface 4 in the normal direction. In this embodiment, the device 1, in particular the opening 5, the cover 7, the first distance A, the second distance B, the third distance C, the rim 8 and / or the interruption 9, is dimensioned to allow for a substantially complete drainage of the liquid, taking into account capillary action and / or surface tension of a liquid, especially water. It has been found that a height F between 2 mm and 10 mm, in particular between 4.8 mm and 5 mm, and especially preferably 5 mm, is advantageous.It has further been shown that a thickness of the rim 8 of at least 1.8 mm, preferably 2 mm, is advantageous. It has further been shown that a depth of the opening 5 between 1 mm and 5 mm, preferably 2.5 mm, is advantageous. It has further been shown that a diameter of the opening 5 between 3 mm and 15 mm, preferably 7.5 mm, is advantageous. Fig. 2 further shows that in this embodiment, the membrane 6 is arranged on the first surface 3.

[0043] Fig. 3 shows a sectional perspective view of an exemplary first embodiment of a device according to the invention. Rounded edges G are shown, which are present on the inner or outer edges of the device 1. It has been found that a radius of between 0.3 mm and 0.6 mm, preferably 0.3 mm, is advantageous for the rounded edges G. This simplifies manufacturing, prevents stress cracks, and facilitates the flow of liquid. Figs. 3 to 8 each show a perspective view of an exemplary second, third, fourth, fifth, and sixth embodiment of a device according to the invention. These embodiments differ from the first embodiment shown in Figs. 1-3 essentially by a different design of the end pieces 10 and the extension 11. In the fifth embodiment of the device 1 shown in Fig. 7, the rim 8 does not include any end pieces 10.In these embodiments, the cover 7 is essentially disc-shaped. It is also possible in these embodiments to design the cover 7 in the shape shown and described in Fig. 1. The sixth embodiment of the device 1, shown in Fig. 8, comprises a cover 7 which, viewed in the normal direction to the second surface 4, covers an entire area of ​​the opening 5. It is also possible to provide this dimension for the cover 7 in the other embodiments.

[0044] In all Figures 1-8, the device 1 is shown integrally integrated into a housing 2. The outer edge of the figures does not represent a physical edge of the housing 2. The figures are merely a graphical representation. The second surface 4 can coincide with an outer surface of the housing 2, and the first surface 3 with an inner surface of the housing 2. However, according to the invention, it is also possible for the device 1 to be a separate element.

[0045] Reference symbol list

[0046] 1 Device

[0047] 2 cases

[0048] 3 First surface 4 Second surface

[0049] 5 Opening

[0050] 6 Membran

[0051] 7 Cover

[0052] 8 Border 9 Interruption

[0053] 10 End piece

[0054] 11. Extension

[0055] 12 Connecting section

[0056] A First distance B Second distance

[0057] C Third Distance

[0058] F height

[0059] G Rounding

Claims

Patent claims 1. Device (1) for pressure equalization in a housing (2), comprising: - a first surface (3); - a second surface (4), wherein the second surface (4) is arranged facing away from the first surface (3); - an opening (5), wherein the opening (5) extends from the first surface (3) to the second surface (4); - a gas-permeable membrane (6) which seals the opening (5) in the area of ​​the first surface (3) in a liquid-tight manner; and - a cover (7) which is arranged in the area of ​​the second surface (4) and, when viewed in the normal direction to the second surface (4), covers at least a central area of ​​the opening (5).

2. Device (1) according to claim 1 , characterized in that the cover (7) is arranged in the normal direction to the second surface (4) with a first distance (A) to the opening (5).

3. Device (1) according to one of claims 1 or 2, characterized in that the device (1) further comprises a border (8), wherein the border (8): - is located on the second surface (4) and protrudes from the second surface (4); - the opening (5) and the cover (7) at least partially surrounded, and - has a break (9).

4. Device (1) according to claim 3, characterized in that the perimeter (8) comprises end pieces (10) which are arranged starting from the interruption (9) along the second surface (4) extending away from the opening (5).

5. Device (1) according to one of claims 3 or 4, characterized in that the cover (7) has a projection (11) extending the cover (7) which is arranged substantially parallel to the second surface (4) pointing towards the interruption (9).

6. Device (1) according to one of claims 3 to 5, characterized in that the border (8) protrudes further from the second surface (4) in a normal direction to the second surface (4) than the cover (7).

7. Device (1) according to one of claims 1 to 6, characterized in that the device (1), in particular - the opening (5), - the cover (7), - the first distance (A), - any second distance (B) between an inside of the border (8) and an outer edge of the cover (7), - any third distance (C) between an edge of the opening (5) closest to the interruption (9) and an end of the end pieces (10) furthest from the interruption, - the possible border (8) and / or - the possible interruption (9), with regard to a capillary effect and / or surface tension of a liquid, in particular water, is dimensioned to allow for a substantially complete outflow of the liquid.

8. Device (1) according to one of claims 1 to 7, characterized in that the device (1), except for the membrane (6), is formed in one piece.

9. Housing (2), in particular for electronic components, with a device according to one of claims 1 to 8, characterized in that the device (1) is integrated into the housing (2) in such a way that the device (1) enables pressure equalization in the housing (2).

10. Housing (2) according to claim 9, characterized in that the housing (2) and the device (1), excluding the membrane (6), are formed in one piece.

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