Patent Description:
A housing for a windscreen wiper motor as per the preamble of Claim <NUM> is already known from practice. The known housing has two housing parts, wherein one of the two housing parts is in the form of a housing cover and is connected to the other housing part in order to form a closed, sealed-off housing of a windscreen wiper motor. The two housing parts are connected to one another with the interposition of a sealing element in order to prevent the ingress of media, in particular of moisture, into the housing interior. The connection of the two housing parts is realized in practice by means of multiple fastening screws. In the known housing, the housing cover has a recess for receiving the sealing element, wherein the sealing element is composed of a thermoplastic elastomer which additionally has adhesive additives. Said adhesive additives are required because the sealing element is injected into, and fills out, the recess of the cover that has been produced previously in an injection-moulding process in a first manufacturing step. Owing to the different characteristics of the materials for the housing cover and for the seal element, the sealing element would not remain adhered in the recess without said adhesive additives, which in particular could lead to the sealing element adopting an undefined position within the recess, thus for example impairing the subsequent assembly of the two housing parts and the reliability of the sealing action. A disadvantage here is that the use of the adhesive additive in the material for the sealing element, which makes it possible for the sealing element to be fixed in the recess without other components, has an adverse effect on the sealing characteristics of the sealing element.

Other examples of housing for a windscreen wiper motor are described in the documents <CIT> and <CIT>.

Taking the presented prior art as a starting point, the invention is based on the object of further developing a housing for a windscreen wiper motor as per the preamble of Claim <NUM> such that the sealing element of said housing is fixed in the recess in the housing part even without the use of adhesive additives for the sealing element and without the use of additional components. In this way, the sealing characteristics of the sealing element are positively influenced, and thus the sealing function is improved. Said object is achieved according to the invention, in the case of a housing for a windscreen wiper motor having the features of Claim <NUM>, in that the recess is designed such that a positively locking connection is formed between the sealing element, which is arranged in the recess, and the housing part. Such a positively locking connection makes it possible for the sealing element to be fixed and positioned within the recess without the use of additional components or adhesive additives, which eliminates the above-mentioned disadvantages of the prior art.

Advantageous refinements of the housing according to the invention for a windscreen wiper motor are specified in the subclaims.

According to the invention, it is proposed that the recess is of groove-like form, and that, in order to form the positively locking connection, the cross section of the recess widens or narrows at least in regions between a mouth region of the recess and a groove base. Such a groove-like recess is in this case formed, in particular in the connecting region, as a closed, that is to say encircling recess or groove in order to obtain a closed sealing contour between the two housing parts that are connected to one another.

According to the present invention, the cross section of the recess has a plane of symmetry.

In this way, any tensile or detachment forces that may be transmitted to the sealing element are distributed uniformly over the cross section of the recess and of the sealing element, such that local stress peaks with corresponding deformations of the sealing element, which could possibly otherwise lead to detachment of the sealing element from the recess, are reduced or eliminated.

According to the present invention, it is proposed that the cross section of the recess is at least substantially rectangular and comprises two planar side walls from which there extend, in an intermediate region, two elevations, wherein the elevations are spaced apart from the groove base. Therefore the recess can be implemented in a particularly simple manner from a manufacturing aspect.

In particular, it may be provided that the at least one elevation is in the form of a convex rounded formation. Such a convex rounded formation has the advantage that, owing to the omission of sharp-edged regions, any mechanical load that may be exerted on the sealing element is reduced. Furthermore, such a rounded form also facilitates the removal of the housing part from an injection-moulding tool.

In a further design refinement of the recess, it is proposed that the groove base is of convexly domed form. Such a form additionally improves the removal of the housing part from its injection-moulding tool.

Furthermore, the removal of the housing part from an injection-moulding tool is made easier if the recess is formed on a housing wall which is, at least in the region of the recess, elastically deformable in a plane perpendicular to the recess. In this way, it is made possible for the injection-moulding tool, which, to form the recess, has in the region of the recess a (web-like) cross section corresponding to the recess, to be pulled out of the recess, wherein the housing wall can deflect elastically perpendicular to the pulling-out direction of the tool. This is of significance in particular in conjunction with the recess which has a varying cross section at the side walls.

The formation of a positively locking connection between the sealing element and the recess and the housing part makes it possible in particular to dispense with adhesive additives in the material of the sealing element, whereby the sealing characteristics of said sealing element are improved.

The invention also encompasses a method for producing a housing for a windscreen wiper, wherein, in a first manufacturing step, a housing with a recess is manufactured from plastic in an injection moulding process, and wherein subsequently, a sealing element is inserted into the recess in a second manufacturing step. It is provided according to the invention that, after the second manufacturing step, the sealing element is held in the recess by means of a positively locking connection. Such a method according to the invention also makes it possible, for example, for a sealing element which is produced in a separate tool, and which is provided as a prefabricated sealing element, to be subsequently fastened in the recess in the second manufacturing step, in particular by being pushed or pressed in. Even in this case, with a prefabricated sealing element, secure retention of the sealing element on the housing part is achieved by means of the positively locking connection.

In a very particularly preferred refinement of the invention, it is however also provided that, in the second manufacturing step, to form the sealing element, a liquefied, thermoplastic elastomer is injected into the recess. In this way, it is possible in particular to generate virtually any desired positive-locking geometries between the sealing element and the recess and/or the housing part because, owing to the fact that the sealing element is formed directly in the recess of the housing part, it is possible to dispense with a manufacturing process, that would otherwise take place in a separate tool, for the sealing element.

Finally, the invention encompasses a windscreen wiper motor that uses a housing according to the invention. A windscreen wiper motor of said type has the advantage that the components arranged in the housing of the windscreen wiper motor are protected in a particularly effective manner against the ingress of media into the housing.

Further advantages, features and details of the invention will emerge from the following description of preferred exemplary embodiments and from the drawing, in which:.

In the figures, identical elements or elements of identical function are denoted by the same reference numerals.

<FIG> illustrates a windscreen wiper motor <NUM> such as is used in particular in a motor vehicle for the at least indirect actuation of windscreen wipers. The windscreen wiper motor <NUM> has a drive motor <NUM> in the form of an electric motor, which is flange-mounted on a housing <NUM> according to the invention of the windscreen wiper motor <NUM> by means of fastening screws <NUM>. The housing <NUM> serves for accommodating a gearing (not illustrated in the figures) which serves for transmitting the drive input rotational speed of the drive motor <NUM>, with a simultaneous increase of the torque thereof, to a drive output element <NUM> which projects out of the housing <NUM> and which serves for the actuation of the one or more windscreen wipers.

In the exemplary embodiment illustrated, the housing <NUM> is of two-part form and is composed of a first housing part <NUM>, in which substantially the said gearing is arranged, and a second housing part <NUM>, which is connected to the first housing part <NUM> by means of further fastening screws <NUM>. The first housing part <NUM> is of substantially pot-shaped form and is also referred to as gearing housing <NUM>, whereas the second housing part <NUM>, corresponding to the illustration in <FIG>, is of substantially shell-shaped form and forms a housing cover <NUM>. Also formed on the housing cover <NUM> is a connection socket <NUM> which serves for the electrical contacting and actuation of the drive motor <NUM> via a wiring loom of the vehicle.

The housing part <NUM> of the housing <NUM> is preferably composed of aluminium and is formed as a pressure die casting, whereas the housing part <NUM> or the housing cover <NUM> is composed of plastic and is formed as an injection moulded part. Such a form of the housing cover <NUM> makes it possible in a particularly simple manner for the housing cover <NUM> to have arranged therein conductor paths <NUM> or contact tabs <NUM>, which serve for example for the electrical contacting of the drive motor <NUM> and which have been manufactured beforehand in a separate tool as punched/bent elements and which, during the formation of the housing cover <NUM>, are placed into the injection moulding tool which forms the housing cover <NUM>.

To prevent media such as vapours, moisture or the like from ingressing into the interior of the housing <NUM>, and for example damaging electrical or electronic components provided therein, during operation after the assembly of the windscreen wiper motor <NUM>, a seal element <NUM> as shown in <FIG> and <FIG> is arranged in the connecting region between the two housing parts <NUM>, <NUM>.

The sealing element <NUM> is composed of a thermoplastic elastomer and, in particular, has no adhesive additives such as may be used in the prior art to increase adhesion between a sealing element <NUM> and a housing part <NUM>, <NUM> composed of plastic. In the exemplary embodiment illustrated, the sealing element <NUM> is connected to, and/or arranged partially in, the housing cover <NUM>. For this purpose, the housing cover <NUM> has, on the face side of an encircling, closed housing wall <NUM>, a likewise encircling, that is to say closed, groove-shaped recess <NUM>, as can be seen from <FIG>. It can likewise be seen from <FIG> that the recess <NUM> in the housing cover <NUM> has a substantially rectangular form with a plane of symmetry <NUM>.

The recess <NUM> has two planar side walls <NUM>, <NUM> arranged parallel to one another, and on the side opposite the mouth region <NUM> of the recess <NUM>, a groove base <NUM> which is of domed, in particular convexly domed form. Close to the groove base <NUM>, but axially spaced apart therefrom, two in each case convexly domed elevations <NUM>, <NUM> project from the two side walls <NUM>, <NUM> in the direction of the plane of symmetry <NUM>. The recess <NUM> thus has a reduced cross section (in the direction perpendicular to the plane of symmetry <NUM>) in the region of the elevations <NUM>, <NUM>. The two elevations <NUM>, <NUM> serve for the formation of a positively locking connection <NUM> between the sealing element <NUM> and the housing cover <NUM>.

It can be seen from <FIG> that, with respect to the plane of symmetry <NUM>, the sealing element <NUM> is arranged with only a sub-region, which in the illustrated exemplary embodiment amounts to up to approximately half of the sealing element, within the recess <NUM>, whereas a sub-region <NUM> of the sealing element <NUM> that projects out of the recess <NUM> bears, on the side facing away from the housing cover <NUM>, against a planar face surface <NUM> of the first housing part <NUM> or of the gearing housing <NUM>, and is deformed in a barrelled manner so as to generate the sealing action.

To produce the housing cover <NUM> with the sealing element <NUM> which is arranged therein by means of the positively locking connection <NUM>, in a first manufacturing step, the second housing part <NUM> or the housing cover <NUM> is produced in an injection-moulding tool, wherein, as discussed, the conductor paths <NUM> and the contact tabs <NUM> are also placed into the injection-moulding tool. During the removal of the housing part <NUM> from its tool, the wall regions to both sides of the elevations <NUM>, <NUM> deflect elastically in a direction perpendicular to the plane of symmetry <NUM> in order to release the web-like element that forms the recess <NUM>. In the housing cover <NUM> thus formed, the sealing element <NUM> is subsequently generated or produced in the recess <NUM> by injection of the liquid thermoplastic elastomer, preferably using the injection-moulding tool. Here, the material of the sealing element <NUM> fills out the entire recess <NUM>. After the sealing element <NUM> has solidified, said sealing element is received and fixed in the recess <NUM> of the housing cover <NUM> by means of the positively locking connection <NUM>.

Claim 1:
Housing (<NUM>) for a windscreen wiper motor (<NUM>), wherein the housing (<NUM>) is composed of at least two housing parts (<NUM>, <NUM>) that can be connected to one another, said housing (<NUM>) comprising a sealing element (<NUM>) and wherein said sealing element (<NUM>) composed of elastic material is arranged in the connecting region between the two housing parts (<NUM>, <NUM>), which sealing element is at least partially received in a recess (<NUM>) in one of the two housing parts (<NUM>, <NUM>), the recess (<NUM>) being designed such that a positively locking connection (<NUM>) is formed between the sealing element (<NUM>), which is arranged in the recess (<NUM>) of one housing part (<NUM>), wherein the recess (<NUM>) is of groove-like form, and the cross section of the recess (<NUM>) having a plane of symmetry (<NUM>) and being at least substantially rectangular and comprises two planar side walls (<NUM>, <NUM>) from which there extends two elevations (<NUM>, <NUM>) and wherein the two elevations (<NUM>, <NUM>) are spaced apart from the groove base (<NUM>).
characterized
in that, with respect to the plane of symmetry (<NUM>), the sealing element (<NUM>) comprises a sub-region (<NUM>) which projects out of the recess (<NUM>), the sub-region (<NUM>) bearing, on a side facing away from a second housing part (<NUM>), against a planar surface (<NUM>) of a first housing part (<NUM>) and the sub-region (<NUM>) being deformed in a barrelled manner so as to generate the sealing action,
in that, in order to form the positively locking connection (<NUM>), the cross section of the recess (<NUM>) widens or narrows at least in regions between a mouth region (<NUM>) of the recess (<NUM>) and a groove base (<NUM>).