Sealing assemblies used for static sealing of components susceptible to icing damage.

Abstract

The present invention relates to a sealing assembly for statically sealing a disc-shaped sensing and / or optical component (1; 1') susceptible to icing hazards relative to a component housing (2; 2') abutting thereon on its edge side, comprising at least one elastomeric sealing element (3; 4; 4'; 4"; 4"') disposed therebetween for static housing sealing, the elastomeric sealing element being equipped with a device for electrically heating to achieve de-icing heat transfer from the elastomeric sealing element (3; 4; 4'; 4"; 4"') to the component component (1; 1'), wherein the device for electrically heating the sealing element (3; 4; 4'; 4"; 4"') comprises an electrically conductive elastomer capable of being charged with electrical energy through at least two mutually spaced-apart electrical contact portions (5; 5a, 5b) permanently disposed on the sealing element (3; 4; 4'; 4"; 4"').

Description

Technical Field

[0001] The present invention relates to a sealing assembly for statically sealing a disc-shaped sensing and / or optical component component susceptible to icing relative to a component housing abutting thereon on the edge side. The sealing assembly includes an elastomeric sealing element disposed between the component component and the component housing for static housing sealing. The elastomeric sealing element is equipped with a device for electric heating to achieve heat transfer for de-icing from the elastomeric sealing element to the component component.

[0002] The application of this invention primarily extends to automotive technology. For example, to ensure that camera systems and sensors in motor vehicles are quickly ready for use even in cold temperatures, these systems and sensors should be de-iced when needed and remain ice-free during operation. Furthermore, they need to be protected from fogging due to moisture. For this purpose, a heat source is typically installed near the foremost optical lens in the camera system. Other sensors, such as ultrasonic or radar sensors, as external components, also have disc-shaped covers, often made of plastic, which must be permeable to sensor signals. For this purpose, a heat source is also needed near the cover for de-icing. In this way, ice and snow can be melted during a cold start of the vehicle, and the cover can be kept ice-free and snow-free during driving, thus eliminating the need for alternative wipers or spray systems. Furthermore, the sealing assembly according to the invention can also be applied outside of automotive technology, i.e., in technical fields that use similarly constructed components susceptible to icing, such as in building technology or household appliance technology. Background Technology

[0003] Document WO 2013 / 092964 A2 discloses a heating element that also achieves the aforementioned purpose of interest here, for use in various motor vehicle technologies, and also as a heating device for contact surfaces of glass, exterior mirrors, etc.

[0004] The heating element includes at least one thermoelectric heating element made of thermoplastic conductive plastic and capable of being powered by at least two printed leads. Here, the printed leads are applied using a thermal spraying method, particularly by standardized plasma spraying. The applied printed leads are then electrically connected to electrical connection points, particularly to at least one contact pin.

[0005] For mounting on the rear side of an exterior mirror, known heating elements can be constructed in a disc shape and are preferably composed of sintered spheres or granules made of the thermoplastic conductive plastic used herein.

[0006] Such surface heating devices require corresponding additional structural space and are therefore unsuitable for disc-shaped sensing or optical components of the type of interest, as the surface heating device would block the light path.

[0007] Furthermore, existing technologies generally known provide a sealing assembly for statically sealing components susceptible to icing. This assembly is equipped with an electric heating device to facilitate heat transfer for de-icing from the sealing element to the component. For this purpose, a heating wire or similar material is typically combined with the sealing element. Summary of the Invention

[0008] The objective of this invention is to provide a sealing assembly for statically sealing disc-shaped sensing and / or optical components susceptible to icing hazards, the sealing assembly comprising a device for an electrically heated sealing element that is technically simple to manufacture and reliably functions.

[0009] This task is solved based on the sealing assembly described in the preamble of claim 1, combined with the features of its characteristic portion. The subsequent dependent claims describe advantageous extensions of the invention.

[0010] The present invention includes the following technical teachings: a device for an electrically heated sealing element includes an elastomer capable of conducting electricity, which can be charged with electrical energy through at least two spaced-apart, permanently arranged electrical contact portions on the sealing element.

[0011] In other words, this allows the elastomeric sealing element itself to be used as a heat source. This has the advantage that the elastic clamping force of the sealing element relative to the component to be de-iced can be used for efficient heat transfer. Furthermore, no separate component requiring structural space is needed for the additional heating device. The invention utilizes the structural design fact that sealing elements used for static housing sealing are mostly the components that the last facets of sensing and / or optical components abut. Experiments have shown that electrical loading of the conductive elastomer (which results in a current along its cross-section) causes sufficient heating of the sealing element, and the resulting heat energy can be transferred to the component abutting it on the edge side for adequate de-icing. The heating device according to the invention does not obstruct the optical path through the disc-shaped sensing or optical component.

[0012] Furthermore, using an elastomer for the purposes according to the invention has the following advantages: the elastomer is cross-linked, and thus the conductive filler contained thereon is immovably fixed in the mesh structure. Moreover, the elastomer material is flexible in response to thermal expansion, and the resulting increased compression of the component to be heated improves heat transfer. Furthermore, the sealing effect is naturally improved simultaneously. Furthermore, the elastomer material of the sealing element generally does not suffer from aging due to significant expansion during its service life, because the sealing element is within an expansion range that is inconsequential to the elastomer. In contrast, thermoplastics commonly used in the prior art for similar purposes have only a small degree of expansion at break and suffer undesirable aging through repeated thermal expansion processes until thermomechanical failure.

[0013] According to the first embodiment, the sealing element can be configured as an insertion member arranged in a circumferential groove introduced on the side of the component housing or on the edge of the component part. Through such a circumferential groove that can extend in a radial or axial direction, the prefabricated sealing element can be easily inserted and electrically contacted. Typically, additional fixing devices such as locking crowns are required. (e.g., as fixed components)

[0014] Alternatively, according to the second embodiment, the sealing element can also be directly molded as an injection-molded part or similar element on the edge side of the component or on the side of the component housing. Additionally, retaining grooves can be provided on the component housing or component to enhance the stability of the connection. Injection molding also has the advantage of establishing reliable electrical contact at the electrical contact points of the sealing element. Besides injection molding, other suitable initial molding methods can also be used, such as 3D printing from different material compositions.

[0015] In the molding of sealing elements, the contact area of ​​the sealing element may additionally be provided with an adsorbent to improve conductivity at the connection point. Such adsorbents, which are known per se, may be applied to the contact pins before manufacturing the sealing element or, alternatively, incorporated into the elastomer material. If no special adsorbent is used, sufficient insertion (Verkrallung) of the contact pins into the elastomer material should be ensured by compression through the remaining portion of the deformation pressure of the elastomer material.

[0016] In particular, the disc-shaped sensing or optical component is constructed in a circular shape, such that the matching elastomeric sealing element is constructed in the form of a closed ring. Here, the sealing element preferably has exactly two opposing contact portions, which are interconnected by two current paths of equal length. These equal-length current paths are thus formed by two mirror-symmetrical semicircles of the annular sealing element and allow for uniform heating of the sealing element along its entire periphery in a simple manner. Furthermore, it is also conceivable that the sealing element has other preferably closed shape configurations, which are typically pre-defined by the edge profile of the disc-shaped component to be sealed.

[0017] According to a further improvement to the invention, the contact points are respectively achieved by inserting or clamping metal contact pins into the conductive elastomeric material of the sealing element. After contact, the thermal expansion of the elastomeric material advantageously further enhances the clamping.

[0018] For the purposes of the invention, it is preferable to use elastomeric base materials for manufacturing sealing elements, these elastomeric base materials being components of the following group of elastomeric materials, including: natural rubber, thermoplastic elastomers, ethylene propylene diene monomer (EPDM), silicone, and fluororubber.

[0019] The filler for the sealing element that generates conductivity in such an elastomeric base material is preferably selected from the group of conductive materials including: metal particles, carbon black, graphite, carbon fiber, and carbon nanotubes.

[0020] Experiments have shown that the proportion of filler material in the sealing element should be between 10% and 70% by volume to achieve the de-icing effect according to the invention in applications where applicable, without consuming excessive electrical energy. Ideally, a volume percentage between 30% and 50% has proven particularly effective for achieving the aforementioned optimization objectives. By mixing the components, the unit resistance of the sealing element can be adjusted according to existing structural edge conditions, and furthermore, the relatively high coefficient of thermal expansion of the elastomeric base material can be used to enable self-adjustment of the seal in the sense of the so-called PTC effect (positive temperature coefficient).

[0021] In the sense of a preferred application of the solution according to the invention, the disc-shaped component is constructed as an optical lens for a camera system, a headlight glass for a vehicle lighting device, or an optically opaque cover for an ultrasonic or radar sensor. Furthermore, other preferred disc-shaped components (which have housing seals on their edge sides and are susceptible to icing at their mounting location) may be equipped with the solution according to the invention.

[0022] In the case of headlights, in addition to the de-icing function, fogging of the glass can also be prevented. This has been achieved up to time by using the residual heat of the lighting device. However, with the increasing use of LED lights as lighting devices, less heat is released in the headlights, making it less reliable to prevent fogging. Therefore, the solution according to the present invention provides a remedy for this. Attached Figure Description

[0023] Further improvements to the invention are shown in detail below with reference to the accompanying drawings and the description of preferred embodiments.

[0024] The attached diagram shows:

[0025] Figure 1 A partial longitudinal section of the optical lens assembly of a camera system having a sealing assembly according to the invention, according to a first embodiment;

[0026] Figure 2 A partial longitudinal section of the optical lens assembly of a camera system having a sealing assembly according to the invention, according to a second embodiment;

[0027] Figure 3 A partial longitudinal section of the optical lens assembly of a camera system having a sealing assembly according to the invention, according to a third embodiment;

[0028] Figure 4 A schematic longitudinal section of another camera system in the first embodiment, having a locking crown and a sealing assembly according to the invention;

[0029] Figure 5 According to another embodiment, a sealing assembly is provided. Figure 4 A schematic longitudinal section detailing the camera system;

[0030] Figure 6A -B is a schematic longitudinal section used to illustrate electrical contact in the sealing assembly according to the invention according to the first embodiment;

[0031] Figure 7A -B is a schematic longitudinal section used to illustrate electrical contact in the sealing assembly according to the invention according to the second embodiment;

[0032] Figure 8 A schematic longitudinal section used to illustrate the details of electrical contact. Detailed Implementation

[0033] according to Figure 1In a camera system for a motor vehicle (not shown in further detail), a disc-shaped optical component 1 in the form of a front lens is used, which, along with various other optical lenses, is used in a tubular lens holder that serves as the component housing 2. The external surface of the optical component 1 is subject to dew and icing at its mounting location in the motor vehicle due to the corresponding environmental influences. The optical component 1 is statically sealed relative to the component housing 2 by a radially annular elastomeric sealing element 3 and an axially annular elastomeric sealing element 4.

[0034] Within the scope of this sealing assembly, the axially annular elastomeric sealing element 4 is composed of an electrically conductive elastomer. Electrical energy can be applied to the elastomer via two opposing, permanently arranged electrical contact portions 5 (only one shown here), causing the sealing element 4 to heat up. This heat is then transferred to the disc-shaped component 1 based on the clamping force applied to it, thus achieving the desired de-icing effect. The electrical contact portions 5 are implemented by inserting or clamping metal contact pins 6 into the electrically conductive elastomeric material of the sealing element 4. The sealing element 4 is configured as an insertion member arranged in a circumferential groove 7 constructed between the component housing 2 and the adjacent lens. Good heat transfer is achieved due to the relatively large contact area of ​​the sealing element 4 on the component 1 to be heated.

[0035] However, according to Figure 2 Alternatively, only one radially arranged annular elastomeric sealing element 3 may be equipped with a device according to the invention for electric heating, thereby introducing heat transfer from the radially outer edge region to the component 1.

[0036] According to Figure 3 The combined variant shown in the figure has an annular elastomeric sealing element 3 arranged radially and an annular sealing element 4 arranged axially between component 1 and component housing 2, both constructed from an elastomeric material according to the invention. Here, the elastomeric material can be electrically loaded via a common metal contact pin 6' to achieve an electrical contact portion 5 (exemplarily). The metal contact pin 6 is implemented using a repeatedly bent metal sheet, which is not inserted into the elastomeric sealing elements 3 and 4, but rather rests against the respective sealing underside. Compared to the two embodiments described above, this sealing assembly can introduce maximum heat input into the component 1 to be heated.

[0037] exist Figure 4In the illustrated embodiment of the camera system, the system is essentially composed of a camera housing 7 having a sleeve-shaped component housing 2' inserted therein, with a component component 1' configured as an optical lens arranged at the distal end of the component housing 2'. The component component 1' is releasably fixed to the component housing 2' via a threaded connection using a locking crown member 8. Here, the disc-shaped component component 1' is pressed against an axially arranged elastomeric sealing element 4' on its edge side, the elastomeric sealing element 4' being constructed of an electrically conductive elastomeric material according to the invention. Heat transfer is also achieved here. At the distal end of the sleeve-shaped component housing 2', at the end of the optical path formed through the component housing 2', an optical sensor 9 of the camera system is arranged. A power supply 10 is also used here to electrically load the electrically conductive sealing element 4', for which two metal contact pins 6a and 6b are arranged opposite each other on the sealing element 4'. In this way, two current paths of equal length are formed, starting from both sides of the contact pins 6a and 6b respectively, ensuring uniform heating of the sealing element 4'.

[0038] exist Figure 5 In the variant of the camera system described above, the conductive elastomeric sealing element 4" constructed according to the present invention is configured as a shape-locking multiple sealing element, which not only provides a seal relative to the component 1' in the axial direction, but also provides a seal relative to the locking crown 8 screwed onto the component housing 2' in the radial direction. Here, the annular elastomeric sealing element 4" has a wider contact surface in the axial direction than in the above embodiment, in order to improve heat transfer to the component 1'.

[0039] Figure 6A and 6B The sequence clarifies the first possibility of mechanical and electrical connection for the first and second contact portions 5a and 5b of the elastomeric sealing element 4"', in the case of the component housing 2'. Here, according to Figure 6A In the first step, metal contact pins 6 (exemplarily) provided for each electrical contact point 5a and 5b are first inserted into the tool before passing through the injection-molded component housing 2' and then injection-molded into it. Figure 6B Next, a conductive elastomer material is injected into the recessed area in the component housing 2' to form a conductive sealing element 4"'. The adhesion of the elastomer material to the end side of the metal contact pin 6 is improved by adding an adhesion promoter. In principle, this achieves the coverage of the metal contact pin 6 with the injected conductive elastomer material from the injection site 11.

[0040] In comparison, Figure 7A and 7BThe sequence illustrates a second possibility of electrical and mechanical connection of the contact pins 6 (exemplarily) at the two contact points 5a and 5b. This second possibility is achieved through the so-called insertion (Einstitchen) of the two metal contact pins 6 (exemplarily) into the pre-formed annular elastomeric sealing element 4". Here, according to Figure 7A In the first step, the sleeve-shaped component housing 2' is first injection molded through injection site 12. Then, a conductive elastomeric material is injected through another injection site 11 to form the sealing element 4"'. Subsequently, two metal contact pins 6 (exemplarily) are inserted into the elastomeric material, according to... Figure 7B These two metal contact pins are inserted into the component housing 2' and / or the sealing element 4"'. According to... Figure 8 As shown in the details, the metal contact pin 6 is inserted into the component housing 2' by a barb 13a formed on the metal contact pin 6 in this area, and in contrast, insertion into the sealing element 4"' is also achieved by another barb 13b arranged on the distal side of the metal contact pin 6.

[0041] The present invention is not limited to the embodiments described above. Variations thereof are also contemplated and are included within the scope of the following claims. Thus, for example, the sealing assembly according to the invention could be used for other components susceptible to icing, such as optically opaque covers for headlight glass, ultrasonic or radar sensors, etc.

Claims

1. A sealing assembly for statically sealing a disc-shaped sensing and / or optical component (1; 1') susceptible to icing hazards relative to a component housing (2; 2'), wherein, The component housing rests against the sensing and / or optical component on its edge side. The sealing assembly includes at least one elastomeric sealing element (3; 4; 4'; 4"; 4"') disposed between the component housing and the sensing and / or optical component for static housing sealing. The elastomeric sealing element is equipped with a device for electric heating to achieve heat transfer for de-icing from the elastomeric sealing element (3; 4; 4'; 4"; 4"') to the component (1; 1'). The device for electrically heating the sealing element (3; 4; 4'; 4"; 4"') includes a conductive elastomer that can be electrically charged through at least two spaced-apart electrical contact portions (5; 5a, 5b) permanently disposed on the sealing element (3; 4; 4'; 4"; 4"'). The sealing element (3; 4; 4'; 4"; 4"') is characterized in that it comprises a first section located in the component housing (2; 2'), a second section located on the end face of the component housing (2; 2'), and a third section connecting the first section and the second section, wherein the radial width of the third section is smaller than the radial width of the first section and the second section, wherein the sensing and / or optical component (1; 1') has a surface facing and in contact with the end face of the component housing (2; 2'), and the second section is located in a groove disposed on the surface of the sensing and / or optical component (1; 1').

2. The sealing assembly according to claim 1, Its features are, The conductive elastomer of the sealing element (3; 4; 4'; 4"; 4"') increases in volume due to heat when powered, thereby improving the sealing effect by significantly increasing the clamping force on the component housing (2; 2') and the component component (1; 1').

3. The sealing assembly according to claim 1, Its features are, The sealing element (3; 4; 4'; 4"; 4"') is configured as an insertion member arranged in a circumferential groove (7) introduced into the side of the component housing (2) or the component part (1).

4. The sealing assembly according to claim 1, Its features are, The sealing element (3; 4; 4'; 4"; 4"') is constructed as an injection molded part and is formed on the edge side of the component part (1') or on the side of the component housing (2').

5. The sealing assembly according to claim 1, Its features are, The elastomeric sealing element (3; 4; 4'; 4"; 4"') is constructed in the form of a closed ring.

6. The sealing assembly according to claim 5, Its features are, The sealing element (3; 4; 4'; 4"; 4"') has exactly two opposite contact portions (5) that are connected to each other by two current paths of equal length.

7. The sealing assembly according to claim 1, Its features are, The contact portion (5) is achieved by inserting or clamping a metal contact pin (6) into the elastomeric material of the sealing element (3; 4; 4'; 4"; 4"').

8. The sealing assembly according to claim 1 or 4, Its features are, The contact area (5) of the sealing element (3; 4; 4'; 4"; 4"') is provided with an adsorbent to improve conductivity.

9. The sealing assembly according to claim 1, Its features are, The elastomer base material of the sealing element (3; 4; 4'; 4"; 4"') is selected from the following elastomer material group, which includes: natural rubber, thermoplastic elastomer, ethylene propylene diene monomer (EPDM) rubber, silicone, and fluororubber.

10. The sealing assembly according to claim 9, Its features are, The filler that generates electrical conductivity in the elastomeric base material of the sealing element (3; 4; 4'; 4"; 4"') is selected from the group of conductive materials including: metal particles, carbon black, graphite, carbon fiber, and carbon nanotubes.

11. The sealing assembly according to claim 9 or 10, Its features are, The proportion of filler material in the sealing element (3; 4; 4'; 4"; 4"') is between 10% and 70% by volume.

12. The sealing assembly according to claim 9 or 10, Its features are, The proportion of filler material in the sealing element (3; 4; 4'; 4"; 4"') is between 30% and 50% by volume.

13. The sealing assembly according to any one of the preceding claims, Its features are, The disc-shaped component (1; 1') is constructed as an optical lens, headlight glass, or an optically opaque cover plate for an ultrasonic or radar sensor.

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