Abstract:
A generator carrier for a driver&#39;s gas bag module has an outer wall. On the outer wall at least one insert contour is provided for the arrangement of a function module. A function module for a steering wheel of a motor vehicle has a plug-in contour for fastening to a component of the steering wheel.

Description:
TECHNICAL FIELD  
         [0001]    The invention relates to a generator carrier for a driver&#39;s gas bag module. The invention further relates to a function module for a steering wheel of a motor vehicle. The invention further relates to an assembly of a generator carrier and a function module, and also to a steering wheel for a motor vehicle.  
         BACKGROUND OF THE INVENTION  
         [0002]    Gas generator carriers are sheet metal or plastic parts which, figuratively, form the bridge between the gas generator of a gas bag module and the steering wheel skeleton. The gas generator is usually mounted directly on the gas generator carrier, and the latter is connected directly or indirectly with the steering wheel skeleton.  
           [0003]    Modern steering wheels are also increasingly being equipped with switches, e.g. for operating an audio system, a car telephone or an on-board computer, and with electronic modules in which, for example,, electric circuits are housed for signal processing. The switches are arranged in switch modules, which like the electronic modules are fastened to the steering wheel skeleton as separate components by means of intermediate plates or the like, which makes the installation expensive and renders a precise positioning relative to other adjoining components, in particular to the generator carrier, more difficult.  
           [0004]    It is an object of the invention to simplify the switch and electronic modules and to facilitate the exchange of these function modules.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    According to the invention, a generator carrier for a driver&#39;s gas bag module has an outer wall, on the outer wall at least one insert contour being provided for the arrangement of a function module. The generator carrier according to the invention therefore enables a simple attaching of one or more function modules with an installation position of the modules which is given in a defined manner. Thereby, an improvement is achieved with regard to the accuracy of position of the function modules on the generator carrier and relative to adjoining components of the steering wheel such as the covering cap of the gas bag module, the steering wheel spokes etc. In addition, as a whole the assembly of the steering wheel is simplified. The construction of the generator carrier according to the invention provides the possibility of combining the generator carrier and the function modules into a pre-assembled structural unit. Additional installation parts for the function modules can be dispensed with, so that the number of components is reduced and the structural space which is available in the steering wheel is better utilized.  
           [0006]    According to a further aspect of the invention, a function module for a steering wheel of a motor vehicle has an insertion contour for fastening on a component of the steering wheel. The plug-in contour makes possible a simple arrangement, in precise position, of the function module on the steering wheel.  
           [0007]    The invention further provides an assembly of a generator carrier according to the invention and a function module according to the invention. One embodiment of the assembly according to the invention proves to be particularly advantageous, in which a cable harness is laid inside the generator carrier, which is guided into the region of the insert contour, one end of the cable harness being bared and fastened in the region of the insert contour, and in which a contact lead of the function module is guided into the region of the plug-in contour, one end of the contact lead being bared and fastened in the region of the plug-in contour. Through this development, the wiring of the function module is substantially simplified, because an electric connection is automatically brought about with the insertion of the function module. Additional work for contacting is no longer necessary.  
           [0008]    The invention also provides a steering wheel for a motor vehicle with an assembly according to the invention.  
           [0009]    Advantageous designs of the connection of the function modules to the steering wheel, in accordance with the invention, will be apparent from the sub-claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 shows a perspective exploded view of an assembly according to the invention, without cabling;  
         [0011]    [0011]FIG. 2 shows a perspective view of the assembly of FIG. 1 in an assembled state with cabling, according to a first embodiment of the invention;  
         [0012]    [0012]FIG. 3 shows a diagrammatic sectional view of a generator carrier according to the invention in the region of the outer wall, according to a second embodiment of the invention;  
         [0013]    [0013]FIG. 4 shows a diagrammatic sectional view of a switch module according to the second embodiment of the invention; and  
         [0014]    [0014]FIG. 5 shows a sectional view of the generator carrier of FIG. 3 and of the switch module of FIG. 4 in an assembled state. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    In FIG. 1 a generator carrier is illustrated for a gas bag module, which is intended for installation into a steering wheel of a motor vehicle. On the generator carrier  10 , which may consist, for example, of plastic or sheet steel, a gas generator for filling a gas bag is installed prior to incorporation of the generator carrier  10 . FIG. 1 shows, in relation to the driver&#39;s view onto the steering wheel incorporated in the motor vehicle, a rear view (i.e. the side facing away from the driver) of the generator carrier  10 . The generator carrier  10  is constructed substantially in a cup shape with a base plate  12  and an encircling outer wall  14 . Insert contours  16  are formed on the outer wall  14  externally, in relation to the view of the driver, on the left, right and lower side.  
         [0016]    In FIG. 1 in addition several function modules  18 ,  20  are shown, namely two switch modules  18  with button switches  22  and one electronic module  20 . The function modules  18 ,  20  have T-shaped plug-in contours  24  matching the insert contours  16 , so that the function modules  18 ,  20  can be simply fixed onto the generator carrier  10  in accordance with the arrows A. To secure the connection between the function module and the generator carrier, a suitable detent mechanism (not illustrated) is respectively provided. In the embodiment shown in FIG. 1, in relation to the view of the driver, a switch module  18  is provided in each case on the left and on the right edge and also an electronic module  20  on the lower edge of the generator carrier  10 ; however, other configurations are also possible.  
         [0017]    [0017]FIG. 2 shows the assembly of generator carrier  10  and function modules  18  in the state when being assembled and wired. The function modules  18 ,  20  are connected with the electronic module  20  by means of a cable harness  26 , preferably a flat band cable, guided on the outer wall  14  of the generator carrier  10 . The electronic module  20  itself is connected via a further cable harness  28  with a unit for controlling corresponding vehicle facilities, for example.  
         [0018]    [0018]FIGS. 3 and 5 relate to the assembly shown in FIG. 1, but with a different wiring from the one illustrated in FIG. 2. In FIG. 3 it can be seen that a flat band cable  30  connected with the electronic unit  20  (not shown in FIGS.  3  to  5 ) is laid inside the generator carrier  10 . The cable  30  is guided through an opening  32  in the outer wall  14  of the generator carrier  10  into the region of the insert contour  16 , where the end  34  of the cable  30  is fastened. However, the cable  30  can also be laid on the outer wall  14  and be guided from there into the region of the insert contour  16 . In the switch module  18  illustrated in FIG. 4, a contact lead  36  is guided into the region of the plug-in contour  24 . The end  38  of the contact lead  36  is fastened in the region of the plug-in contour  24  and is bared, like the end  34  of the cable  30 . The ends  34 ,  38  of the cable  30  and of the contact lead  36 , respectively, are arranged so that on fixing of the switch module  18  onto the generator carrier  10 , automatically an electric connection is produced, similar to a telephone socket/plug connection. The electric connection of the cable  30  with the electronic module  20  can be realized in the same way.  
         [0019]    Instead of the use of cables and contact leads, electrical paths can also be vaporized three-dimensionally onto the (plastic) generator carrier  10  or onto the housings of the function modules  18 ,  20  (in accordance with the so-called MID technique) and bared in the region of the contact points.  
         [0020]    The connection of the function modules  18 ,  20  according to the invention makes possible a simple exchange of the function modules  18 ,  20  for example in a case of warranty.