Abstract:
An electronic control device for use in a vehicle has a metallic housing ( 10 ) to accommodate electronic components of the device Plural shaped guide elements ( 14 ) are formed on the inside of the housing ( 10 ) Fastening members ( 24 ) for an electronic component ( 26 ) can be engaged in a form-fitting manner into elongate channels defined by the rail-shaped guide elements ( 14 ).

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to an electronic control device for use in vehicles, which has a metallic housing to accommodate electronic components of the control device  
         BACKGROUND OF THE INVENTION  
         [0002]    The electronic components accommodated in the metallic housing of such an electronic control device serve, for example, to control occupant restraint systems connected to the control device, such as belt tensioners and airbags In order for the device to function reliably and dependably, it is important for the electronic components to be firmly connected to the housing body However, it is also desirable to have the fastest and simplest possible assembly of the electronic components as well as a housing body that can be used for various electronic components Known housings for such control devices have guide grooves on their side walls in which a printed circuit board can be slid into the housing. In the inserted position, the printed circuit board is additionally supported by guide elements formed on the rear of the housing. Since the guide elements are attached to the side and rear, it is necessary for the printed circuit board to occupy the entire length and width of the housing.  
         SUMMARY OF THE INVENTION  
         [0003]    The invention provides a control device whose electronic components are reliably and rigidly connected to the housing body and whose housing body can be used to accommodate electronic components of various sizes According to the invention, the metallic housing has a wall with a at least one internal rail wherein an elongate channel is formed that widens internally A fastening, member has a head portion inserted and retained in the channel and a pin portion connected to one of the electronic components Due to the interaction of the internal rail with the fastening member, the electronic component is securely and reliably attached to the housing Therefore, it is possible to dispense with a rear guide element so that, for example, the same housing can be used, irrespective of the size of the printed circuit board and of the electronic modules situated on it.  
           [0004]    According to preferred embodiment, the housing is provided with external integrally shaped cooling ribs A power semiconductor located on a printed circuit board is attached via the fastening member to the housing in thermal contact therewith. Thanks to the large cooling surface area of the housing, the heat generated by the power semiconductor can be dissipated into the environment 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    Additional features and characteristics ensue from the description below of several embodiments and from the drawings to which reference is made In the drawings:  
         [0006]    [0006]FIG. 1 is a perspective view of a control device according to the invention with a metallic housing on whose side walls mounting brackets are attached,  
         [0007]    [0007]FIG. 2 is a schematic side view of the control device according to the invention of FIG. 1,  
         [0008]    [0008]FIGS. 3 a  and  3   b  are schematic top views of two different variants of the arrangement of the mounting brackets to a plug collar attached to a side wall of the control device;  
         [0009]    [0009]FIG. 4 is a perspective view of a control device with a mounted plug collar and gasket,  
         [0010]    [0010]FIG. 5 is a perspective view of a control device according to the invention in another embodiment, with a plug collar whose inside has receptacles for condensers,  
         [0011]    [0011]FIG. 6 is a perspective view of another embodiment of a control device according to the invention whose housing has laterally attached profile rails,  
         [0012]    [0012]FIG. 7 is a perspective view of a control device according to another embodiment with a housing whose outside has cooling ribs attached to it;  
         [0013]    [0013]FIG. 8 is a schematic view of a printed circuit board with a power semiconductor that is connected to the housing via a fastening element that has an internal thread and that is arranged in a rail-shaped guide element 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    The control device shown in FIGS. 1 and 2 has a housing  10  with a housing body  11 , on the inside of whose bottom wall  12  there are three parallel rail-shaped guide elements  14  that extend across the entire length of the bottom wall  12  The housing body  11  also has a cover wall  16  and two side walls  18  The housing body  11  is preferably made of aluminum in one piece by means of impact extrusion. The rail-shaped guide elements  14  each form an internally widening channel  22 . A metallic fastening member  24  has a head portion inserted into the channel  22 . The head portion of fastening member  24  is shaped in such a way that it engages in a form-fitting manner with the internally widened channel  22  of the rail-shaped guide element  14  At its upper end relative to FIG. 2, the fastening element  24  has a pin portion attached to a printed circuit board  26 . The fastening member  24  can be, for example, a pin or a stud that is pressed onto an opening formed in the printed circuit board  26   
         [0015]    In order to mount the printed circuit board  26  in the housing body  11 , the head portion of the fastening member  24  is first attached to the printed circuit board  26 . Then the printed circuit board  26 , at whose one end a plug socket  28  is attached (also see FIG. 1), is inserted into the housing body  11 , namely, in such a way that the lower end of the fastening member  24  relative to FIG. 2 engages with the internally widened channel  22  of the rail-shaped guide element  14  and is slid along this channel. Since the fastening member  24  and the channel  22  interengage in a form-fitting manner, the printed circuit board can only be slid along the guide rails but no longer in the two directions perpendicular to that. The printed circuit board  26  is completely inserted in the housing and secured in place when the plug socket  28  is latched at the front end  30  of the housing body  11   
         [0016]    In order to fully block the fastening member  24  with the printed circuit board  26  in the channel  22 , the housing body  11  is locally deformed from the outside in the area  31  of the bottom wall  12 , which is located below the fastening member  24 . At the same time, this creates an electrically conductive connection between the printed circuit board  26  and the housing body  11  via the fastening member  24   
         [0017]    Via the fastening member, which is blocked in the channel of the rail-shaped guide element, the printed circuit board is reliably and rigidly connected to the housing body Since the fastening member can be fastened anywhere on the printed circuit board, the same housing can be used to accommodate printed circuit boards of differing sizes.  
         [0018]    In order to attach the housing  10  to the car body, each of the side walls  18  of the housing body  11  has a mounting bracket  32  with a first bracket leg  34  and a second bracket leg  36  arranged perpendicular to the first one In order to fasten the mounting bracket  32  to the side walls  18 , according to the embodiment shown in FIGS. 1 and 2, there are two rib-like projections  38  formed onto a side wall  18  of the housing body  11 . These rib-like projections  38  can each be inserted and pressed into slits that are formed on the first bracket leg  34  of the mounting bracket  32  and that are complementary to the rib-like projections. The second bracket legs  36  of the mounting bracket  32  are each provided with openings  40  through which the housing  10  can be fastened, for example, screwed to the car body.  
         [0019]    The mounting brackets—like the left-hand mounting bracket  32  relative to FIG. 1—can be arranged with respect to the housing  10  in such a way that the second bracket leg  36 , in which the openings  40  are formed, runs parallel to the bottom and top walls of the housing and projects towards the outside relative to the housing  10 . The mounting brackets, however, can also be arranged like the right-hand mounting bracket  32  relative to FIG. 1 in such a way that the second bracket leg  36  extends at least partially below the bottom wall of the housing body  11 . The opening or the openings  40  are then in the vicinity of the bracket leg  36 , which is not situated below the bottom wall  12  of the housing  10 , but rather protrudes laterally.  
         [0020]    The attachment of the housing  10  to the car body via the mounting brackets  32  has the advantage that the same housing can be mounted in installation places with differently shaped fastening points in that, depending on the installation place, mounting brackets with differently shaped openings  40  are attached to the side walls of the housing body  11 . Furthermore, the arrangement of the mounting brackets can also be used to vary the length of the control device, as will now be explained with reference to FIGS. 3 a  and  3   b    
         [0021]    [0021]FIG. 3 a  shows a housing body  11  with two mounting brackets  32  that each have a greater length than the side wall  18  of the housing body  11  to which they are attached, so that the ends  41  of both of them project laterally The plug socket  28  is situated on the side wall of the housing body  11  across from the two laterally projecting ends  41 , and said plug socket  28  extends over almost the entire width of the side wall  18  of the housing body  11  In the control device shown in FIG. 3 b,  the mounting brackets  32  project beyond the side wall  18  of the housing body  11  on which the plug socket  28  is located. As a result, in contrast to the control device shown in FIG. 3 a,  the plug socket  28  cannot extend essentially over the entire width of the side wall but rather only over the area of the side wall  18  that lies between the laterally projecting ends  41  of the mounting bracket  32  Thanks to the arrangement of the mounting brackets  32  vis-a-vis the plug socket  28  shown in FIG. 3 b,  a control device length can be obtained that is shorter than that of the arrangement shown in FIG. 3 a    
         [0022]    In order to seal off the plug socket  28  with respect to the housing body  11 , the plug socket  28  has a gasket  42  that lies on the outside of the housing, body  11  in the mounted state (also see FIG. 4)  
         [0023]    According to another embodiment, shown in FIG. 5, the inside area of the plug socket  28  is configured with receptacles  46  to receive capacitors  48 . On their end opposite from the plug socket  28 , the capacitors  48  are electrically in contact with a printed circuit board  50  The installation of the capacitors  48  in the receptacles  46  in the inside area of the plug collar allows a simple assembly of the capacitors Moreover, this saves space so that smaller dimensions are possible for the housing body  11   
         [0024]    Instead of fastening the housing  10  to the car body by means of the mounting brackets  32 , according to the invention, as shown in FIG. 6, it is also possible to fasten profile rails  44  with openings  52  to the housing body  11  The profile rails  44  have the advantage over the mounting brackets  32  that they are made of less material and can thus be manufactured less expensively.  
         [0025]    In the electronic control device shown in FIG. 7, the reference numerals corresponding to those of the embodiments shown in FIGS. 1 through 6 are used increased by 100.  
         [0026]    The control device shown in FIG. 7 differs from the control devices shown in FIGS. 1 through 6 in that, on the top wall  116  of the housing body  111 , cooling ribs  150  are formed. The cooling ribs  150 , like the rail-shaped guide elements  114 , can be manufactured together with the side walls  118 , the top wall  116  and the bottom wall  112  in one piece by means of impact extrusion This housing is preferably suited for accommodating power electronic components since, due to the large cooling surface area of the housing body, the generated heat can be dissipated.  
         [0027]    An assembly of a printed circuit board  126  with a power semiconductor  160  arranged on it in the housing body  111  is shown in FIG. 8 One end of a fastening member  124 , analogously to the embodiment shown in FIG. 2, is connected to a printed circuit board  126  and its other end engages in a form-fitting manner with the internally widened channel  122  of a rail-shaped guide element  114 . The bottom wall  112  of the housing body Ill is locally depressed on the outside of the housing body  111  in the area of the fastening member  124  in order to block the fastening member  124  in the channel  122 . The fastening member  124  is provided with an internal thread The power semiconductor  160  has a cooling vane  162  to which the power semiconductor is connected by means of a screw  164  inserted into the internal thread of the fastening member  124 . In this manner, the heat generated by the power semiconductor can be dissipated via the screw  164  and via the fastening member  124  on the housing body  111  and from there to the environment