Abstract:
The invention relates to a housing ( 10 ) or housing part ( 11 ) for a control device of a motor vehicle, having a surface structure ( 22 ) deviating at least partly from a flat plane, wherein the surface structure ( 22 ) comprises a plurality of planes ( 24, 26; 30, 32, 34 ) whose superficial dimensions are substantially equally large.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    A known way of reinforcing load-bearing parts, housings or housing parts is to provide these with a honeycomb structure in conjunction with the lightest possible construction. DE 42 32 953 A1, for example, shows a production method for reinforcing vehicle bodies or other components susceptible to torsion, with the aim of reducing the specifically rigidity-related space taken up by additional body reinforcements, and of optimizing the rigidity-related weight increase. Use is made here of a sandwich structure, in which a flexible intermediate layer of very low specific weight, which keeps two outer, thin covering layers a distance apart, leads to a very rigid and moreover lightweight overall structure. JP 2007215328 and DE 10 2004 002 276 A1 show a comparable construction for vehicle bodies. 
         [0002]    SU 1836811 A3 discloses the provision of a housing having a smooth and thin outer surface on the inside with a lightweight reinforcing frame, which has a honeycomb-like structure. Housings or housing parts having ribbed structures, which bring only an insignificant increase in weight but lead to a very high rigidity, are also known. 
       SUMMARY OF THE INVENTION 
       [0003]    Compared to the state of the art, the housing or housing part according to the invention for a control unit of a motor vehicle, having a surface structure deviating at least partially from a plane surface, affords the advantage that it achieves a very high rigidity and fracture resistance in conjunction with a saving in the housing volume and material by virtue of a relatively small wall thickness. For this purpose it is proposed that the surface structure be composed of multiple planes, the areas of which are substantially equal in size. 
         [0004]    It is particularly advantageous if the individual planes of the surface structure have the same contours, which are of triangular, quadrilateral or hexagonal shape. The contours therefore join together without interstices, which further increases the fracture resistance and rigidity. 
         [0005]    The torsional rigidity of the housing or housing part can moreover be improved if the surface structure is composed of at least three planes. 
         [0006]    Material can furthermore be saved if the surfaces of the inside and outside of the housing or housing part are inverted relative to one another in the area of the surface structure, so that a completely smooth surface does not remain on any side. In addition or alternatively it is possible for the surface structure to extend over at least an entire side of the housing or housing part, except for areas for connections and identification marking areas. 
         [0007]    If the individual planes are connected to one another in such a way that the wall thickness between the planes substantially corresponds to the wall thickness of the planes, it is advantageously possible to obtain a constant rigidity distribution in the area of the surface structure. 
         [0008]    It is advantageously possible for electronic components of the control unit to be arranged in the area of the surface structure, in such a way that they utilize the overall space created by the various planes, so that the total volume of the housing is reduced overall. If the housing or the housing part is made of metal, its enlarged surface moreover allows it to be used as a cooling element in connection with electrical components generating a lot of heat, for example power transistors. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    In the drawings 
           [0010]      FIG. 1  shows a first exemplary embodiment of a housing according to the invention, 
           [0011]      FIG. 2  shows a perspective sectional view of a second exemplary embodiment of a housing or housing part according to the invention, 
           [0012]      FIG. 3  shows an enlarged detail of the perspective sectional view in  FIG. 2 , and 
           [0013]      FIG. 4  shows a further exemplary embodiment of the housing or housing part according to the invention in a perspective sectional view. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]      FIG. 1  shows a housing  10  of a control unit, not further represented, of a motor vehicle. The housing  10  has openings for connections  12  of the control unit, via which the control unit is connected by power and/or data connections to other units, not further specified. Webs  14 , lugs  16  and fastening catches  18  for fixing a circuit board (not shown) of the control unit are also provided. 
         [0015]    In order to reduce the housing volume and material and to increase the housing rigidity and the fracture resistance compared to housings with ribbed structures, the underside  20  of the housing  10  shown in  FIG. 1  is provided throughout with a surface structure  22 , which deviates from a plane surface in that it is composed of two planes  24  and  26 , the areas of which are substantially equal in size. For this purpose, both planes  24  and  26  have identical contours  28  —in this case a plurality of quadrilaterals, the number of recessed quadrilaterals identifiable in the first plane  24  corresponding approximately to the number of raised quadrilaterals in the second plane  26  and the individual quadrilaterals of the two planes  24  and  26  being virtually equal in size. 
         [0016]      FIG. 2  shows a perspective sectional view of a further exemplary embodiment of an inventive housing part  11  of a housing  10  for a control unit of a motor vehicle. In contrast to  FIG. 1 , the surface structure  22  now comprises three planes  30 ,  32  and  34 , the contours  28  of the three planes  30 ,  32  and  34  now being of hexagonal shape. It can again be seen that the areas of the three planes  30 ,  32  and  34  are virtually equal in size, since they do not differ substantially from one another in the number of hexagons and their areas. 
         [0017]    The surfaces of the inside  36  and outside  38  of the housing part  1  are furthermore designed so that they are inverted in relation to one another in the area of the surface structure  22 . In contrast, therefore, to a housing in which only the inside has a multi-level surface structure  22 , whilst the outside is of completely plane design, for example, it is additionally possible to save material without the rigidity and fracture resistance suffering. In order to be able to provide the housing  10  according to the invention with type identification markings or other inscriptions, however, it is further proposed that the surface structure  22  should not extend over the area of identification marking surfaces  39  and electrical and/or mechanical connections  12 . 
         [0018]      FIG. 3 , by way of illustration, shows an enlarged detail of the perspective view of the housing part  11  in  FIG. 2 . The three different planes  30 ,  32  and  34  with their hexagonal contours  28  are clearly discernible. Also very clearly visible here is the inversion between the inside  36  and outside  38  in the area of the surface structure  22 . 
         [0019]      FIG. 4  shows a further perspective sectional view of the surface structure  22  of the housing  10  according to  FIG. 1  for two planes  24  and  26  with quadrilateral contours  28 . It will be clear from this that the wall thickness A of the webs  40  between the planes  24  and  26  is substantially equal to the wall thickness B of the planes  24 ,  26 . This affords a high degree of homogeneous fracture resistance and rigidity of the housing  10  or housing part  11  in the area of the surface structure  22 . 
         [0020]      FIG. 4  also represents a component  42  of the control unit, for example a capacitor, which is arranged in the area of the surface structure  22  in such a way that it makes optimum use of the overall space afforded by the various planes  24  and  26 . In this way it is possible to minimize the overall volume of the housing. 
         [0021]    It should finally be pointed out that the exemplary embodiments shown are not limited to  FIGS. 1 to 4 . Thus, for example, in addition to quadrilateral and hexagonal contours of the individual planes, triangular contours may also be used. The number of planes is also not limited to a maximum of three. Plastics and/or metal may be used as material of the housing  10  or the housing part  11 . With a metal housing, in particular, the enlarged surface affords an improved cooling effect.