Title of Invention

A FLEXIBLE GASKET AND A METHOD FOR PRODUCING THE SAME

Abstract

A flexible gasket between two housing parts, preferably for an electrical instrument, and a production method for the gasket are proposed. The sealing compound (3) is applied to at least one predetermined sealing surface (2) between the housing parts (1) and is clamped between the housing parts (1) when these are joined together. The sealing compound (3) consists of butyl rubber, preferably with mineral fillers, which is heated before being applied to the sealing surface (2). In the method for producing the flexible gasket, the sealing compound (3) is transported to a heated applicator nozzle by means of a piston pump and a following gear pump, and, after the cooling of the sealing compound (3), the housing parts (1) are joined to one another and the sealing compound (3) experiences plastic deformation.

Full Text

The invention relates to a flexible gasket and to a method of producing the same. A gasket for an electrical instrument, with two housing parts, is already known from German Offenlegungsschrift 3,937,190. The known electrical instrument contains control electronics for an automatic anti-lock facility (ABS/ABSR) of a brake system of a motor vehicle and is mounted in the region of the engine space. After the electrical instrument has been fitted, the housing is to be leakproof for a lengthy period of time and is to protect the sensitive electrical circuit element inside it particularly against moisture and aggressive foreign substances. In the case of a motor vehicle, for example splashwater, salty mist, dust or other chemical agents occurring at the place of installation of the control electronics may lead to harmful effects. The known gaskets are, as a rule, moulded or stamped gaskets made from elastomers, which are attached to the housing parts. Advantages of the Invention The flexible gasket according to the invention of the type specified above, having the characterizing features of claim 1, is advantageous particularly in that, when the housing parts are joined together, the sealing compound can penetrate into the roughness of the joining surface and thus lead to an elastic and highly leakproof connection of the housing parts. In contrast to the known gaskets made from elastomers, the gasket according to the invention does not incur any tool costs for the mouldings or any stamping waste in the case of gaskets stamped out of plates. Contrary to other materials which can be applied in plastic form, such as, for example, silicone or acrylates, in the sealing compound according to the invention there is no need for any curing, since the butyl rubber cools immediately after the gasket has been applied. The chemical separation products, such as acetic acid, methanol, amines or monomeric acrylates, occurring in the known methods are also not emitted in the sealing compound according to the invention, so that, altogether, an environmentally friendly production process can be implemented. Disposal can also be carried out in an environmentally friendly way, since, during the recycling of the housing parts, the butyl rubber, being a hydro¬carbon, burns in the metal melt to form carbon dioxide and water. According to Subclaim 2, an improvement in the plastic properties and processability of the sealing compound is advantageously brought about by the admixture of mineral fillers. Claim 3 and the following subclaims specify an advantageous production method for the flexible gasket according to the invention, which method guarantees a simple application of the heated sealing compound com¬posed of butyl rubber onto the sealing surfaces and, after the cooling of the sealing compound which has taken place in a few seconds, allows a plastic and leakproof connection of the two housing parts. Accordingly, the present invention provides a flexible gasket between two housing parts, preferably for an electrical instrument, with a sealing compound which is arranged on at least one predetermined sealing surface between the housing parts and which is clamped between the housing parts when these are joined together, characterized in that the sealing compound consists of butyl rubber which can be heated when it is applied to the sealing surface. Accordingly, the invention also provides a method of producing a flexible gasket as described above, wherein transporting a sealing compound to a heatable applicator nozzle by means of a piston pump and a following gear pump, guiding the applicator nozzle along a predetermined sealing surface by means of a freely programmable path control, followed by cooling of the sealing compound to join die two housing parts by plastic deformation of the sealing compound. An exemplary embodiment of the flexible gasket according to the invention is explained with reference to the drawing. In this: Figure 1 shows a top view of a housing part of an electrical instrument, with a bead-like sealing compound consisting of butyl rubber on one sealing surface, and Figure 2 shows a section through the applied sealing compound. Description of the Exemplary Embodiment Figure 1 shows a housing part 1 as an integral part of a housing for an electrical instrument, and this housing part 1 can also be an integral part of a mechan¬ical arrangement which is controlled by the electrical instrument. For example, the housing can contain engine control electronics which are mounted on the engine block of a motor vehicle. A sealing compound 3 consisting of butyl rubber is located on a sealing surface 2 which can be connected to a second housing part not shown here. In this case, the sealing compound 3 consisting of butyl rubber with an addition of mineral fillers has been applied to the sealing surface 2 by means of a heatable applicator nozzle by a piston pump and a follow¬ing gear pump. The piston pump, gear pump and applicator nozzle are an integral part of a conventional path-controlled manufacturing plant which is not shown here. By means of the freely programmable path control, even complicated, for example angled sealing surfaces can be attended to not only two-dimensipnally, but also in the third dimension. In this case, the sealing compound cools in a few seconds after application, so that the housing parts can be joined to one another immediately there¬after, the sealing compound 3 even then still having a plastic behaviour. Figure 2 shows a section through the sealing compound 3 shortly after it has been applied to the sealing surface 2. WE CLAIM: 1. A flexible gasket between two housing parts, preferably for an electrical instrument, with a sealing compound (3) which is arranged on at least one predetermined sealing surface (2) between the housing parts (1) and which is clamped between the housing parts (1) when these are joined together, characterized in that the sealing compound (3) consists of butyl rubber which can be heated when it is applied to the sealing surface (2). 2. The flexible gasket according to claim 1, wherein the mineral fillers are added to the sealing compound (3) consisting of butyl rubber. 3. A method of producing a flexible gasket according to claim 1 or 2, -comprising transporting a sealing compound (3) to a heatable applicator nozzle by means of a piston pump and a following gear pump, guiding the applicator nozzle along a predetermined sealing surface (2) by means of a freely programmable path control, followed by cooling of the sealing compound (3) to join the two housing parts (I) by plastic deformation of the sealing compound. 4. The method according to claim 3, wherein the sealing compound (3) is heated in the applicator nozzle to a temperature of 130°C to 170°C. 5. The method according to one of claims 3 or 4, wherein the sealing compound (3) is a bead formed as a flattened round cord. accompanying drawings. 7. A method for producing a flexible gasket substantially as herein described with reference to the accompanying drawings.

Documents:

843-mas-1996 others.pdf

843-mas-1996 abstract.pdf

843-mas-1996 claims.pdf

843-mas-1996 correspondence others.pdf

843-mas-1996 correspondence po.pdf

843-mas-1996 description (complete).pdf

843-mas-1996 drawing.pdf

843-mas-1996 form-1.pdf

843-mas-1996 form-26.pdf

843-mas-1996 form-4.pdf

843-mas-1996 petition.pdf