KR20220013386A - Seal assembly for static sealing of freeze-prone parts - Google Patents

Abstract

The present invention relates to a sealing assembly for statically sealing a disc-shaped sensor component and/or optical component (1; 1') prone to freezing against a component housing (2; 2') in contact with the edge of said component, The sealing assembly includes one or more elastomeric sealing elements (3; 4; 4'; 4"; 4"') disposed between the two components for static housing sealing, the elastomeric sealing elements (3; 4; 4'; 4"; 4"' are provided with electrical heating means for transferring heat from themselves to the part 1; 1' for preventing icing, said sealing element 3; 4; 4'; 4" 4"') electrical heating means via two or more electrical contacts 5; 5a, 5b which are spaced apart from each other and arranged on the sealing element 3; 4; 4'; 4"; 4"' permanently. an electrically conductive elastomer capable of being supplied with electrical energy.

Description

Seal assembly for static sealing of freeze-prone parts

The present invention relates to a sealing assembly for statically sealing a disc-shaped sensor component and/or optical component susceptible to freezing against a component housing in contact with an edge of said component, said sealing assembly comprising said two components for static housing sealing. at least one elastomeric sealing element disposed between the elements, the elastomeric sealing element having electrical heating means for transferring heat from the sealing element to the component to prevent icing.

The field of use of the present invention extends mainly to automotive technology. For example, in order to make a camera system and sensor equipped in an automobile quickly ready for use even at low temperatures, it is necessary to prevent icing, if necessary, and to prevent icing from occurring during operation. Furthermore, it is necessary to prevent fogging due to moisture. To this end, in general, a heat source is installed near the frontmost optical lens in a camera system. Other sensors such as, for example, ultrasonic sensors or radar sensors also have, as an external part, a disk-shaped cover mainly made of plastic, and the cover must transmit the sensor signal. Even in this case, a heat source near the cover is required to perform anti-icing. In this way, an alternative wiper or spray system is not required, since the ice and snow layers can melt during cold start of the vehicle and the cover can remain ice and snow free during driving. In addition, the sealing assembly according to the invention can also be used in technical fields other than automotive technology, ie in technical fields using similarly constructed components that are prone to freezing, for example in building technology or consumer electronics technology.

WO 2013/092964 A2 discloses, inter alia, a heating element that is also provided for the above-mentioned purpose which is of interest herein, which heating element has a wide range of automotive technology applications, including also its use as a contact heater, in particular for windshields, exterior mirrors, etc. is for

The heating element comprises at least one thermoelectric heater formed of a thermoplastic conductive plastic and capable of being supplied with electrical energy via at least two conductor tracks. In this case, the conductor tracks are formed by thermal spraying, in particular through standardized plasma spraying. The conductor tracks thus formed are each electrically conductively connected to an electrical connection point, in particular to one or more contact pins.

The known heating element can be correspondingly formed in the shape of a plate for attachment to the rear surface of the outdoor mirror, and is preferably composed of sintered balls or particles of the thermoplastic conductive plastic used herein.

Surface heating elements of that type require a corresponding additional footprint, which will block the beam path, and are therefore unsuitable for disc-shaped sensor components or optical components of the type of interest here.

Also known from the generally known prior art are sealing devices for static sealing of components prone to freezing, equipped with electric heating means for transferring heat from the sealing element to the components in order to prevent freezing. For this purpose, a heating wire or the like is generally combined with the sealing element.

The object of the present invention is to provide a sealing device for static sealing of disc-shaped sensor components and/or optical components prone to freezing, which is manufactured simply in terms of manufacturing technology and provided with means of electric heating of the sealing element which acts reliably.

The above object is solved in connection with the features of a sealing device according to the preamble of claim 1 on the basis of that part. The following dependent claims represent preferred refinements of the invention.

The present invention contains the technical teaching that the means for electric heating of the sealing element comprises an electrically conductive elastomer which is spaced apart from each other and can be supplied with electrical energy via two or more electrical contacts which are permanently arranged on the sealing element.

In other words, this allows the elastomeric sealing element itself to be used as a heat source. In this case, it is advantageous that the existing elastomeric contact pressure of the sealing element with respect to the component to be frozen can be used for effective heat transfer. In addition, there is no need for a separate space-consuming component for the additional heating means. The present invention takes advantage of the structural situation that the sealing element for static housing sealing is usually the last component lying flat against the sensor component and/or the optical component. Experiments have shown that the sealing element is sufficiently heated by the supply of electricity to the electrically conductive elastomer, which causes a current flow along the cross-section, whereby the thermal energy generated is transferred to the part in contact with the edge of the sealing element for sufficient freezing protection. It was confirmed that it could be The heating means according to the invention do not obstruct the beam path passing through the disk-shaped sensor component or the optical component.

The use of elastomers for the purposes of the present invention also has the advantage of linking said elastomers so that the electrically conductive filler contained therein is immovably fixed within the network structure. In addition, the elastomeric material can respond flexibly upon thermal expansion, thereby increasing compression against the part to be heated, improving heat transfer. In addition, the sealing effect is naturally improved at the same time. In addition, the elastomeric material of the sealing element does not typically undergo aging due to numerous expansions over its lifetime, since the elastomeric material is within the non-critical expansion range of the elastomer. In comparison, thermoplastics used for similar purposes in the prior art have low elongation at break and can be exposed to undesirable aging due to many thermal expansion processes, leading to thermomechanical failure.

According to a first embodiment, the sealing element can be formed as an insert part arranged on the part housing side or in a peripheral groove formed in the edge of the part. By means of said peripheral groove, which can extend radially or axially, a prefabricated sealing element can be inserted and electrically contacted in a simple manner. As a fastening means, additional fastening means, such as a crown-shaped cap, are usually required.

As an alternative to this, according to the second embodiment, it is also conceivable to form the sealing element integrally as an injection-molded article or directly on the edge of the part or on the part housing side. As a complement to this, fixing grooves may be provided in the component housing or component to enhance the stability of the connection. In addition, injection molding has the advantage that reliable electrical contact can be realized at the electrical contact of the sealing element. In addition to injection molding, other suitable primary molding processes are also available, for example 3D printing based on various material components.

When shaping the sealing element, the contact region of the sealing element may additionally be provided with an adhesive to increase the electrical conductivity at the connection point. These already known adhesives may be applied to the contact pins prior to manufacture of the sealing element or, alternatively, may be added to the elastomeric material. If a separate adhesive is not used, care must be taken for sufficient gripping of the contact pins within the elastomeric material, which is ensured through compression by the remaining deformation pressure of the elastomeric material.

Since the disk-shaped sensor component or optical component mainly forms a circle, an elastomeric sealing element suitable therefor is formed in the shape of a closed ring. In this case, the sealing element preferably has exactly two contacts arranged opposite to each other and connected to each other by two current paths of equal length. In this regard, a current path of equal length is formed by two mirror-symmetrical semicircles of the annular sealing element, which in a simple manner allows the sealing element to be heated uniformly along its entire perimeter. In addition, it is also conceivable that the sealing element has a preferably closed shape, which is defined by the edge contour of another, generally disc-shaped part to be sealed.

In one measure which further improves the invention, the contacts are realized by penetrating or gripping the metal contact pins respectively into the electrically conductive elastomeric material of the sealing element. The contact pressure is further strengthened in an advantageous manner by the expansion of the elastomeric material due to heat after contact.

Elements of the group of elastomeric materials comprising natural rubber, thermoplastic elastomers, ethylene propylene diene monomer rubber (EPDM), silicone, luororubber, for the purposes according to the invention, preferably for the production of sealing elements Phosphorous elastomeric base materials may be used.

The filler material of the sealing element generating electrical conductivity in this elastomeric base material is preferably selected from the group of conductor materials comprising metal particles, carbon black, graphite, carbon fibers, carbon nanotubes.

As a result of the experiment, it was confirmed that in order to achieve the anti-icing effect according to the present invention without using too much electrical energy in the application to the subject of the present invention, the filling material ratio of the sealing element should be within the range of 10 to 70% by volume. . Most preferably, a range of 30 to 50% by volume has proven particularly effective to achieve the aforementioned optimization goals. By means of the mixing ratio, the specific electrical resistance of the sealing element can be adjusted according to the prevailing structural limiting conditions, moreover, the very high coefficient of thermal expansion of the elastomeric base material is achieved in the sense of the so-called PTC (Positive Temperature Coefficient) effect. It can be used for self-limiting of the seal.

In the sense of a preferred application of the solution according to the invention, it is proposed that the disk-shaped component is formed as an optical lens, such as a camera system, a headlight glass for vehicle lighting, or an optically opaque cover plate of an ultrasonic or radar sensor. Furthermore, the solution according to the invention can also be provided for other, preferably disk-shaped, parts in which an edge-side housing seal is implemented and there is a risk of freezing in their installation position.

In the case of the headlight, in addition to the anti-icing function, the fogging of the glass plate can also be prevented. So far, this function has been achieved through the waste heat of the luminous body used. As LED lights are increasingly being used as light sources, less heat is emitted from the headlights and fogging of the headlights is no longer reliably prevented. That is, the solution according to the present invention will be helpful for this as well.

In the following, further measures for improving the present invention are described in more detail together with a description of preferred embodiments of the present invention with reference to the drawings.

1 is a partial longitudinal cross-sectional view of an optical lens assembly of a camera system having a sealing assembly of the present application according to a first embodiment;
Fig. 2 is a partial longitudinal sectional view of an optical lens assembly of a camera system having the present sealing assembly according to a second embodiment;
Fig. 3 is a partial longitudinal sectional view of an optical lens assembly of a camera system having the present sealing assembly according to a third embodiment;
Fig. 4 is a schematic longitudinal cross-sectional view of another camera system having the present sealing assembly and crown-shaped cap according to the first embodiment;
FIG. 5 is a schematic longitudinal sectional view of a detail of the camera system according to FIG. 4 with a sealing assembly according to a further embodiment;
6A to 6B are schematic longitudinal sectional views for explaining electrical contact in the sealing assembly of the present application according to the first embodiment.
7A to 7B are schematic longitudinal cross-sectional views for explaining electrical contact in the sealing assembly of the present application according to the second embodiment.
8 is a schematic longitudinal cross-sectional view for explaining an electrical contact in detail.

According to FIG. 1 , a disk-shaped optical component 1 in the form of a front lens is used in a camera system of an automobile (not shown in detail), and this optical component is a lens in the form of a lens barrel as the component housing 2 . Used with a variety of other optical lenses within the holder. The outer surface of the optical component 1 is exposed to condensation and icing due to environmental influences at the installation location in the motor vehicle. The optical component 1 is statically sealed against the component housing 2 by means of a radially annular elastomeric sealing element 3 and an axial elastomeric annular sealing element 4 with respect to the component housing 2 .

In the scope of said sealing device, here an axial annular elastomeric sealing element 4 is provided with two (here only one of them shown) electrical contacts permanently arranged to lie opposite to each other on this sealing element 4 ( 5) consists of an electrically conductive elastomer, which can be supplied with electrical energy via prevention effect appears. In this case, the electrical contact 5 is embodied in such a way that the metal contact pin 6 penetrates into the elastomeric material of the electrically conductive sealing element 4 and is firmly gripped. In this case, the sealing element 4 is formed as an insert part arranged in a peripheral groove 7 formed between the part housing 2 and an adjacent lens. Since the contact surface of the sealing element 4 to the component 1 to be heated is very large here, good heat transfer is achieved.

According to FIG. 2 , however, it is also possible for only one radially arranged annular elastomeric sealing element 3 to be equipped with an electric heating means according to the invention, whereby heat transfer from the outer radial edge region to the component 1 is possible. ) is induced in

According to the combined variant shown in FIG. 3 , the annular elastomeric sealing element 3 arranged radially between the component 1 and the component housing 2 as well as the axially arranged annular sealing element 4 is also It is formed according to the invention of an electrically conductive elastomer, which can be supplied with electricity (for example) via a common metal contact pin 6 ′ for the realization of the contact 5 . In this case, the metal contact pins 6 are embodied by sheet metal folded several times, which is not inserted into the elastomeric sealing elements 3 , 4 but abuts against the underside of each sealing element. Compared to the two embodiments described above, the present sealing assembly can introduce a maximum amount of heat into the component 1 to be heated.

In the embodiment of the camera system shown in Fig. 4, the camera system consists essentially of a camera housing 7 in which a sleeve-shaped component housing 2' is housed, at the distal end of the component housing an optical lens. A component 1 ′ formed by The part 1' is secured to the part housing 2' via a screw connection so that it cannot be detached by means of a crown-shaped cap 8 . In this case, the edge of the disc-shaped part 1' is pressed onto an axially arranged elastomeric sealing element 4' formed of an electrically conductive elastomer according to the invention. Here too, heat transfer takes place at this point. On the side of the proximal end of the sleeve-like component housing 2', an optical sensor 9 of the camera system is arranged at the end of the beam path formed by the component housing 2'. The power supply 10 is also used here for the supply of electricity to the electrically conductive sealing element 4', for this purpose two metal contact pins 6a, 6b arranged exactly opposite each other in the sealing element 4'. this is provided In this way, two current paths of equal length are created, starting on both sides of the contact pins 6a and 6b, respectively, and ensuring uniform heating of the sealing element 4'.

In a variant of the camera system described above, shown in FIG. 5 , the electrically conductive elastomeric sealing element 4 ′ constructed according to the invention is formed as a form-fitting multiple seal, said multiple seal axially comprising a component ( 1') as well as sealing against the crown-shaped cap 8 screwed to the component housing 2' in the radial direction. In this case, in order to improve the heat transfer to the part 1', the annular elastomeric sealing element 4" has a wider contact surface in the axial direction compared to the embodiment described above.

The sequence of FIGS. 6a and 6b describes a first possibility of the mechanical and electrical connection of the first and second contacts 5a , 5b for the elastomeric sealing element 4″′ under heating of the component housing 2′. In a first step according to Fig. 6a, before (for example) the part housing 2' is molded via injection molding, the metal contact pins 6 respectively provided on the respective electrical contacts 5a, 5b are first attached to the tool It is inserted into and then overmoulded. Subsequently, the injection of electrically conductive elastomeric material for the formation of the electrically conductive sealing element 4"' is empty for this purpose, done in ses The adhesion of the elastomeric material at the end side of the metal contact pins 6 is improved by adding an adhesive. That is, in principle, the overlap molding of the metal contact pins 6 and the electrically conductive elastomeric material is performed starting from the injection point 11 .

In contrast, the sequence of FIGS. 7a and 7b describes (for example) a second possibility of electrical and mechanical connection of the contact pin 6 at the two contacts 5a, 5b. This is done in a so-called penetrating manner (for example) of two metal contact pins 6 into the preformed annular elastomeric sealing element 4″′. In this case, in a first step according to FIG. 7a , first The sleeve-like part housing 2' is injection molded into plastic via an injection point 12, and then an electrically conductive elastomeric material is injected via another injection point 11 for the formation of the sealing element 4"'. do. Two metal contact pins 6 are then penetrated (for example) into the elastomeric material according to FIG. 7b , which are held firmly in the component housing 2' and/or the sealing element 4"' According to the detailed view shown in Fig. 8, the gripping of the metal contact pins 6 in the component housing 2' is carried out in this area via a hook 13a integrally formed on the metal contact pins 6 On the other hand, gripping at the sealing element 4"" is likewise carried out via an additional hook 13b arranged on the distal end side of the metal contact pin 6 .

The present invention is not limited to the above-described embodiments. Rather, modifications that fall within the protection scope of the following claims are also contemplated. It is therefore also possible to use the sealing assembly according to the invention for other freezing-prone components, for example headlight glasses, optically opaque cover plates of ultrasonic or radar sensors, etc.

Claims (12)

A sealing assembly for statically sealing a disc-shaped sensor component and/or optical component (1; 1') susceptible to freezing against a component housing (2; 2') in contact with an edge of said component, said sealing assembly comprising: one or more elastomeric sealing elements (3; 4; 4';4";4"') arranged for static housing sealing between the type sensor component and/or the optical component and the component housing, said elastomeric sealing element (3) 4; 4';4";4"') comprising electrical heating means for transferring heat from itself to the component (1; 1') to prevent icing, the sealing assembly comprising:
The means for electric heating of the sealing element 3; 4; 4';4";4"' are spaced apart from each other and arranged permanently in the sealing element 3; 4; 4';4";4"'. Sealing assembly, characterized in that it comprises an electrically conductive elastomer capable of being supplied with electrical energy via said electrical contacts (5; 5a, 5b). The part housing (2; 2') and the part (1; 1') according to claim 1, wherein the electrically conductive elastomer of the sealing element (3; 4; 4'; 4"; 4"') under the supply of electrical energy Sealing assembly, characterized in that the volume increases due to heat in such a way that the sealing effect is increased by a significant increase in the compressive force against it. 2. The insert according to claim 1, wherein the sealing element (3; 4; 4'; 4"; 4"') is an insert which is arranged in a peripheral groove (7) formed on the part housing (2) side or on the part (1) side. A sealing assembly, characterized in that it can be formed. The sealing element (3; 4; 4'; 4"; 4"') according to claim 1, wherein the sealing element (3; 4; 4'; 4"; 4"') is formed as an injection-molded part, integrally formed with an edge of the part (1') or on the side of the part housing (2'). A sealing assembly, characterized in that it becomes. Sealing assembly according to claim 1, characterized in that the elastomeric sealing element (3; 4; 4'; 4"; 4"') is formed in the shape of a closure ring. 6. The sealing element (3; 4; 4'; 4"; 4"') according to claim 5, wherein the sealing element (3; 4; 4'; 4"; 4"') has exactly two contacts (5) arranged opposite each other and connected to each other by two current paths of equal length. ), characterized in that it has, the sealing assembly. 2. The method according to claim 1, wherein the electrical contact (5) is realized in such a way that the metal contact pin (6) penetrates into the elastomeric material of the sealing element (3; 4; 4'; 4"; 4"') and is firmly gripped. characterized in that the sealing assembly. Sealing according to claim 1 or 4, characterized in that the contact (5) region of the sealing element (3; 4; 4'; 4"; 4"') is provided with an adhesive for increasing the electrical conductivity. assembly. The elastomeric base material of the sealing element (3; 4; 4'; 4"; 4"') comprises natural rubber, thermoplastic elastomer, ethylene propylene diene monomer rubber (EPDM), silicone, fluororubber. A sealing assembly, characterized in that it is selected from the group of elastomeric materials. 10. The elastomeric base material according to claim 9, wherein the filler material of the sealing element (3; 4; 4'; 4"; 4'") generating electrical conductivity in the elastomeric base material is metal particles, carbon black, graphite, carbon fibers, carbon nanotubes. A sealing assembly, characterized in that it is selected from the group of conductor materials comprising: 11. A method according to claim 9 and 10, wherein the proportion of filler in the sealing element (3; 4; 4'; 4"; 4'") is in the range of 10 to 70% by volume, preferably in the range of 30 to 50% by volume. A sealing assembly, characterized in that it is placed within. 12. The method according to one of the preceding claims, characterized in that the disk-shaped part (1; 1') is formed as an optical lens, a headlight glass or an optically opaque cover plate of an ultrasonic or radar sensor. sealing assembly.

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