Housing for a control unit

Abstract

A housing for a control unit of a motor vehicle has a housing element and a further element attached to the housing element by way of a joining technique that does not include a joining layer or by way of a joining layer. The housing element has a main body composed of a light metal and a protective layer applied to the main body. The protective layer is arranged between the main body and the attached further element. The invention further relates to a method for producing a housing and to a control unit.

Claims

1. A housing for a control unit of a motor vehicle, the housing comprising: a housing element having a main body formed of a light metal; a further element attached to said housing element by way of a joining technique that does not use a joining layer or by way of a joining layer; and a protective layer applied to said main body and disposed between said main body and said further element joined to said main body; said main body having a surface, said protective layer composed of a metal applied to said surface of said main body, and said metal of said protective layer corresponding to a predominant element of said light metal in pure form; and said main body formed with a recess, said protective layer configured to encircle said recess, and said further element covering said recess.

2. The housing according to claim 1, wherein said protective layer is applied, in places, to a face of said main body that faces said further element and said protective layer protrudes laterally beyond said further element.

3. The housing according to claim 2, wherein said protective layer projects laterally beyond said joining layer.

4. The housing according to claim 1, wherein said light metal is an aluminum alloy, and said metal of said protective layer is pure aluminum.

5. The housing according to claim 1, wherein said protective layer extends beyond a bearing face for said further element by not more than a predetermined range.

6. The housing according to claim 1, wherein said further element has a cover for closing the housing element.

7. The housing according to claim 1, wherein said further element comprises a functional component.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 shows a housing for a control unit, having a main body from light metal;

(2) FIG. 2 shows a sectional view of a portion of the housing of FIG. 1; and

(3) FIG. 3 shows a flow diagram of a method for manufacturing the housing of FIG. 1.

DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows a housing 100 for a control unit, in particular onboard a motor vehicle, in an exploded illustration. The housing 100 has a housing element 105 having a main body 107 from a light-metal die casting. Without limiting the general aspect, an aluminum die casting may be used in particular. Furthermore, the housing 100 in the present case has two further elements 110 which are adapted for connection to the housing element 105 by means of a joining technology, in particular by adhesive bonding or welding, and which in the completed state of the housing are connected to the housing element 105 by means of a joining technology, in particular by adhesive bonding or welding.

(5) The one further element 110 in the present case has a cover 115 for closing the housing element 105. More specifically, the cover 115 is a housing lid which closes the upper side that is open in order for an electronics board to be inserted during the assembly of the control unit.

(6) The other further element 110 has a functional component 120. In the embodiment illustrated, the functional component 120 contains a pressure-equalization element (PEE) which may have a membrane, in particular. In the assembled state, the membrane covers a recess 215 of the main body 107 of the housing element 105. Said membrane may expediently be liquid-tight and gas-permeable, such that said membrane enables a pressure equalization between the housing interior and the environment and prevents moisture from penetrating through the recess 215. A polytetrafluorethylene (PTFE) membrane may be provided, for example, which may be adhesively bonded to the housing element 105. In the embodiment illustrated, the attachment of the functional element 120 to an external surface of the housing element 105, that is to say to a surface that faces away from the interior space of the main body 107, is provided (obscured in the illustration of FIG. 1). In other embodiments, the functional element 120 may also be attached to an internal surface, for example if said functional element 120 is an electronic element or a fastening element.

(7) A joint 125 is configured where the respective further element 110 is connected to the housing element 105. The element 110 is held on the housing element 105 at the joint 125 by means of a joining technology, in particular by means of an adhesive connection. To this end, a joining layer 130 from an adhesive is disposed in particular in the region of the joint 125, between the further element 110 and the housing element 105. In order for a functional component 120 (PEE) to be fastened, the adhesive 130 may in particular be an acrylate adhesive which in particular is pressure-sensitive, that is to say which builds up the adhesion to the mating partner under mechanical pressure. In order for a cover 115 to be fastened, the adhesive 130 may in particular be a silicone adhesive, for example a moisture-cross linking silicone adhesive.

(8) According to the invention, a protective layer 135 of the housing element 105 is attached to the main body 107. A particularly good joint-type connection between the further element 110 and the housing element 105 is achievable by means of the protective layer 135. In particular, the protective layer 135 may facilitate improved adhesion of the adhesive 130. Furthermore, the protective layer 135 is preferably configured for counteracting any corrosion in the region of the joint 125, in particular any infiltration of the joint 125 by corrosion. On account thereof, it may be prevented that the corrosion reaches an internal region of the housing 100. In particular, electronic components of a control unit that are disposed within the housing may be effectively protected for a prolonged period of time from damaging environmental influences in this way. In the case of the present exemplary embodiment, the protective layer 135 is composed of aluminum, and the main body 107 is composed of an aluminum alloy. Examples of further potential design embodiments of the protective layer 135 and of the main body 107 are described further above.

(9) The joint 125 at which the housing lid (that is to say the cover 115) is fastened to the housing element 105 in order for the open upper side of the housing element 105 to be closed is indicated in a heavily schematic manner in FIG. 1. For example, the upper periphery of the side walls of the main body 107 may be provided with the protective layer 135, and the joining layer 130 may be applied to the upper periphery that is provided with the protective layer 135, for example in the form of an adhesive bead, in particular of a strand of an elastic sealing material. In the case of one design embodiment, the joining layer 130 may at least partially be disposed in a groove of the upper periphery (not illustrated in FIG. 1).

(10) FIG. 2 shows a sectional view of a portion of the housing 100 of FIG. 1, in the region of the joint 125 of the further element 110 which contains the functional component 120 having the membrane. The functional component 120 is illustrated in an exemplary manner in the form of a pressure-equalization element which is already attached to the housing element 105 by means of adhesive bonding.

(11) The protective layer 135 is attached to a surface of the main body 107 of the housing element 105 in the region of the joint 125. Herein, the protective layer 135 preferably extends beyond a bearing face 210 on which the further element 110 is attached to the housing element 105 by a predetermined region 205. In the embodiment illustrated, the further element 110 covers a recess 215 in one of the side walls of the main body 107 such that the bearing face 210 and the protective layer 135 run in an annular manner around the recess 215, and the internal contours of the bearing face 210, of the protective layer 135, and of the recess 215, in the plan view onto the recess 215 are at least substantially congruent.

(12) In the case of the illustrated example of an adhesive connection, the adhesive that forms the joining layer 130 is applied to the protective layer 135. In other embodiments, the adhesive, or the joining layer 130, respectively, may only be provided in the region of the bearing face 210. Optionally, the adhesive may also be applied to the region 205 that runs there beyond and that is not covered by the further element 110, in which region 205 the protective layer 135 in the present exemplary embodiment is exposed. In yet one further embodiment, the adhesive may extend beyond the external contour of the protective layer 135.

(13) The further element 110 is disposed so as to bear on the joining layer 130. In the embodiment illustrated, a tight connection between the further element 110 and the housing element 105 is preferably achieved in that the joining layer 130 is configured so as to completely encircle the recess 215.

(14) FIG. 3 shows a flow diagram of a method 300 for manufacturing the housing 100 of FIG. 1. In a first step 305, the main body 107 is provided. The main body is optionally cleaned in a subsequent step 310. In a further optional step 315, the main body 107 is masked so as to define where the protective layer 135 is applied to the surface of the main body 107 in the subsequent step 320.

(15) The application of the protective layer 135 in step 320 may be performed galvanically, by welding, sputtering, or by way of a metallurgical connection, for example. In a preferred manner, the protective layer is applied by way of a powder-metallurgical compound. Herein, the alloying element of the protective layer 135 may be applied by way of a special method, for example, in which the powder on the housing 100 is fused in a localized manner by means of a plasma ray, so as to subsequently wet the surface.

(16) Thereafter, in a step 325, the further element 110 is joined to the housing element 105 in the region of the protective layer 320. It is preferable herein that joining in step 325 is performed as immediately as possible after the application of the protective layer 135 in step 320. On account thereof, it may be avoided that the surface of the protective layer 135, prior to the further element being attached thereto, is subjected to any contamination. Joining 325 may comprise the application of a joining layer 130, in particular of an adhesive layer.

(17) The joint connection between the further element 110 and the housing element 105 may set or cure in an optional step 330. To this end, curing may be stimulated by means of pressure, ultraviolet light, or heat, for example. The step 330 may be performed simultaneously with further processing steps on the housing 100.