Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to a motor vehicle subassembly according to the precharacterizing clause of claim 1.  
           [0002]    A motor vehicle subassembly of this type comprises a steering wheel body of a motor vehicle steering wheel, an airbag module which can be fastened to the steering wheel body by means of a latching connection, and latching means for fastening the airbag module to the steering wheel body at at least two spaced apart fastening points. The airbag module is accordingly secured on the steering wheel body locally at a plurality of separate fastening points.  
           [0003]    A motor vehicle subassembly of this type is disclosed, for example, in U.S. Pat. No. 5,775,725. A disadvantage of the known motor vehicle subassembly is that, in order to release the latching connection between the airbag module and steering wheel body, the latching connection has to be released at a plurality of fastening points, which requires a corresponding outlay.  
           [0004]    The invention is based on the problem of providing a motor vehicle subassembly of the type mentioned at the beginning, in which the latching connection between the airbag module and steering wheel body can be cancelled in a simple manner.  
         SUMMARY OF THE INVENTION  
         [0005]    This problem is solved according to the invention by the provision of a motor vehicle subassembly having the features of claim 1.  
           [0006]    Accordingly, the latching means provided for fastening the airbag module to the steering wheel body are arranged and designed in such a manner that, after release of the latching means at one fastening point, the airbag module can be removed from the steering wheel body without actuating the latching means of the further fastening points separately. Rather, after release of the latching means at the one fastening point, the airbag module can be removed from the steering wheel body by a simple movement relative to the steering wheel body, in particular by displacing or pivoting it.  
           [0007]    The solution according to the invention has the advantage that, in order to cancel the connection between the airbag module and steering wheel body, the latching means used for fastening the airbag module to the steering wheel body only have to be released at a single fastening point, and the connection can then be cancelled by simple movement of the airbag module.  
           [0008]    In order to release the latching means at the one fastening point, an actuating element, for example in the form of a spring element, which preferably forms part of the latching connection can be provided there. To this end, the latching element, in the latched state, is supported on the actuating element and can be disengaged from the actuating element by moving, in particular displacing or pivoting, and, if appropriate, deforming the said actuating element, as a result of which the latching connection at the one fastening point is released. Expressed in another manner, the latching connection at the one fastening point is only in the latched state if the latching element is supported on the actuating element. Displacing or pivoting the actuating element from the position in which it can be used as a support for the latching element therefore enables the latching connection at the said fastening point to be released in a simple manner.  
           [0009]    According to one embodiment of the invention, the actuating element is coupled not only to the one, but also to the further fastening points of the latching connection, with it also being possible for provision to be made at these further fastening points for the latching elements there to be supported in each case on the actuating element. In this case, it is envisaged that release of the latching connection at the one fastening point also enables the latching connections at the further fastening points to be released by means of the actuating element. This is achieved by a movement of the actuating element leading to the release of the latching connection at the one fastening point having the effect of moving further sections of the actuating element through which the latching connection at the further fastening points is released. There is thus a direct connection (positive coupling) between the movement of the actuating element at the one fastening point and at the further fastening points, specifically in such a manner that the latching connections at all of the fastening points can be released simultaneously if the actuating element is moved in a suitable manner. The actuating element is preferably designed here as a latching hoop which extends from the one fastening point to the further fastening points.  
           [0010]    According to another variant of the invention, the further fastening points are configured in such a manner that the latching connection can be cancelled there by means of a movement of the airbag module relative to the steering wheel body after the latching connection at the one fastening point has been released. If the latching connection at the one fastening point has not yet been cancelled, the said fastening point prevents the said relative movement of the airbag module, with the result that the latter, in the latched state of the latching connection at the one fastening point, cannot be removed from the steering wheel body. In order to be able to take on a function here as a stop, the actuating element is preferably supported on at least one bearing surface of the steering wheel body. The further fastening points can be assigned openings, for example in the form of a respective slot, which make it possible for the airbag module to be removed from the steering wheel body by means of a relative movement along a certain direction, with it being possible for the said direction to be predetermined, for example, by means of the direction of extent of the slots.  
           [0011]    The latching means can be formed at the individual fastening points in each case by means of separate latching elements, in particular in the form of latching hooks, which engage in a respectively assigned latching opening.  
           [0012]    Furthermore, elastic means can be provided via which the airbag module is supported under prestress on the steering wheel body. These elastic means can be formed in a simple manner by individual elastic elements at the respective fastening points, with the elastic elements preferably being arranged on the latching elements at the respective fastening points. For this purpose, the elastic elements can in each case be helical springs which are pushed over the latching elements.  
           [0013]    The elastic elements enable the latching means, in particular in the form of individual latching elements, to be clamped in their respective latching position, with the result that the latching connection can only be released by a movement of the actuating element perpendicular with respect to the direction of the prestress. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    Further features and advantages of the invention will become clear in the following description of exemplary embodiments with reference to the figures, in which:  
         [0015]    [0015]FIG. 1 shows a perspective illustration of a steering wheel body having a subassembly of an airbag module fastened thereto;  
         [0016]    [0016]FIG. 2 shows an exploded illustration of the arrangement from FIG. 1;  
         [0017]    [0017]FIG. 3 shows a perspective illustration of a second embodiment of a steering wheel body having a module holder, which is fastened thereto, for an airbag module;  
         [0018]    [0018]FIGS. 4 a  and  4   b  each show a detail from FIG. 3 at a fastening point for latching the module holder to the steering wheel body. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    [0019]FIGS. 1 and 2 illustrate a steering wheel body  1  having a flat, circular main body  10 , having three holders  11 , which protrude therefrom in the plane of the main body  10 , for steering wheel spokes, and having a hub part  12  which protrudes vertically from the main body  10 , the main body  10  of the steering wheel body also having three fastening openings  15  which are spaced apart from one another along the circumference of the main body and are intended for fastening a module carrier  2  of an airbag module.  
         [0020]    The module carrier  2  is formed by a main body  20  which is of flat design and from which three latching, elements  25  protrude vertically in the form of latching hooks which can be introduced into a respectively assigned fastening opening  15  of the steering wheel body  2 . Arranged in each case on the latching hooks  25  are elastic elements (compression springs) in the form of helical springs  5  via which the main body  20  of the module carrier  2  is supported resiliently on the main body  10  of the steering wheel body  1 . The prestressing force of the elastic elements which are arranged on the latching hooks  25  between the two main bodies  1 ,  2  and are in the form of helical springs  5  also result in the latching connection formed by the latching hooks  25  in the assigned fastening openings  15  being clamped in place and thus counteracts release of the latching connection.  
         [0021]    As can be seen in particular with reference to FIG. 1, the latching hooks  25  are supported with their latching heads  252  not directly on the edge of the respectively assigned fastening opening  15 , but rather on a longitudinally extended, hoop-shaped spring element  3 , which is inserted into a depression  13  in the steering wheel body and is retained there by projections  16 ,  17  protruding above the depression  13 . The hoop-shaped main body  30  of the spring element  3  has respectively inwardly angled end sections  31  at its ends. The end sections  31  are supported on a correspondingly inwardly angled section  14  of the side wall of the depression  13  of the steering wheel body  1 .  
         [0022]    The depression  13  in the steering wheel body  1  and the spring element  3  having the hoop-shaped main body  30  are designed in such a manner that two of the fastening points  15 ,  25 , comprising in each case a latching hook  25  having an assigned fastening opening  15 , are arranged in the vicinity of an angled, free end section  31  of the spring element  3 . In contrast, a fastening point  15 ,  25  is provided in the central region of the main body  30  of the spring element  3  between the two angled end sections  31 .  
         [0023]    In order to release the latching connection (illustrated in FIGS. 1 and 2) of a module carrier  2  to a steering wheel body  1 , the spring element  3  is displaced in the region of the one, central fastening point  15 ,  25  along a displacement direction V perpendicular with respect to the direction along which the latching hook  25  can be introduced into the assigned fastening opening  15 . This causes the latching head  252  of the corresponding latching hook  25  to be disengaged from the main body  30  of the spring element  3  and the latching connection is released at the corresponding fastening point  15 ,  25  (latching point).  
         [0024]    The movement of the main body  30  of the spring element  3  along the displacement direction V perpendicular with respect to the direction in which the latching hook  25  is introduced and away from the side wall of the depression  13 , against which the main body  30  bears, moreover, because the inwardly angled, free end sections  31  of the spring element  3  interact with the assigned wall sections  14  of the depression  13 , has the result that, also in the region of the two further fastening points  15 ,  25 , the main body  30  of the spring element  3  is moved perpendicular with respect to the direction in which the respective latching hook  25  is introduced and is moved inwards away from the wall  14  of the depression  13  in the radial direction R, so that the two further latching hooks  25  are also disengaged from the spring element  3 . By this means, the latching connection is automatically also released at these two fastening points  15 ,  25 , and the module carrier  2  of the airbag module can be removed in a simple manner from the main body  10  of the steering wheel body  1  by the latching hooks  25  being guided through the respectively assigned fastening opening  15 . For this purpose, the fastening openings  15  are dimensioned in such a manner that the respective latching head  252  can be passed in a simple manner through the respective fastening opening  15  if it is not supported on the main body  30  of the spring element  3 .  
         [0025]    As a result, it is thus achieved that actuation of the latching connection, which is effective at all three fastening points  15 ,  25 , at just one fastening point, specifically displacement of an actuating element in the form of a spring element  3  along a displacement direction V, enables the latching connection to be automatically released at all three fastening points. For this purpose, the one fastening point  15 ,  25  is coupled to the further fastening points  15 ,  25  via the actuating element in the form of the spring element  3 .  
         [0026]    A modification of the exemplary embodiment from FIGS. 1 and 2 is illustrated in FIGS. 3, 4 a  and  4   b , in which the substantial difference resides in the arrangement and design of the actuating element  4  which is to be actuated in order to release the latching connection. Otherwise, the two exemplary embodiments correspond, with the result that reference is made in respect of the further details to the corresponding explanations given under FIGS. 1 and 2. Corresponding components are provided in FIGS. 1 and 2, on the one hand, and in FIGS. 3, 4 a  and  4   b , on the other hand, with identical reference numbers in each case.  
         [0027]    It should also first be mentioned that, in the case of the exemplary embodiment according to FIG. 3, it is also possible to see, from the main body  20  of the module holder  2  to be fastened to the steering wheel body  1 , a laterally upwardly protruding edge  21  having latching openings  22  for the fastening of a module cover.  
         [0028]    In the case of the exemplary embodiment according to FIG. 3, an actuating element  4  is arranged only in the region of a fastening point  15 ,  25 , in which, according to FIG. 4 b , at this fastening point  15 ,  25  the fastening head  252  of the latching hook  25  is supported on the main body  40  of the actuating element in the form of a spring element  4 .  
         [0029]    It can furthermore be seen with reference to FIG. 4 b  that the fastening hook  25  engages with a stem  250  around the assigned latching opening  15  in the main body  10  of the steering wheel body  1  and that an elastic element, arranged on the stem  250 , in the form of a helical spring  5  is supported at one end on the main body  10  of the steering wheel body  1  and at the other end on the module end  251  of the latching hook  25 . The module holder  2  is thereby mounted elastically on the steering wheel body  1 . At the same time, the prestressing force of the helical spring  5  which is under prestress (compression spring) results in the latching head  252  of the latching hook  25  being pressed under prestress against the main body  40  of the spring element  4 , so that the latching connection is secured against being released unintentionally.  
         [0030]    It emerges from FIG. 3 that the main body  40  of the spring element  4  has two angled end sections  41 ,  42 , of which the one is supported on a stop  18  of the main body  10  of the steering wheel body  1 . Furthermore, a further section of the main body  40  of the spring element  4 , which section is adjacent to the second, angled end section  42 , is guided in a tab  19  integrally formed on the steering wheel body  1 . The spring element  4  is thereby supported on the main body  10  of the steering wheel body  1 , in particular on the stop  18  integrally formed thereon, and on the tab  19  in such a manner that it prevents the latching element  25  from being displaced in the plane of the main body  10  of the steering wheel body  1 .  
         [0031]    It can be seen with reference to FIG. 4 a  that at the two further fastening points  15 ,  25  the latching hooks  25  are supported with their latching heads  252  in each case directly on the edge  150  of the respectively assigned fastening opening  15 .  
         [0032]    In order to release the latching connection illustrated in FIGS. 3, 4 a  and  4   b , first of all the spring element  4  provided at the one fastening point  15 ,  25  is actuated, with the elasticity (deformability) of the spring element  4  being used in order, on the one hand, to lift it off from the stop  18  at the one free end  41  and, on the other hand, to move it perpendicular with respect to the direction in which the latching hook  25  is introduced into the assigned fastening opening  15  in such a manner that the latching head  252  of the latching hook  25  is disengaged from the main body  40  of the spring element  4 . By this means, the latching connection at the one fastening point  15 ,  25  is released. At the same time, the module holder  2  can be displaced relative to the main body  10  of the steering wheel body  1  in the plane of extent of the main body  10 . As a result, the module holder  2  can be removed from the steering wheel body  1  by a pivoting movement S, which is composed of a displacing movement in the plane of extent of the main body  10  of the steering wheel body  1  and of a movement perpendicular with respect thereto, in which case the latching hooks  25  are guided with their latching heads  252  through the respectively assigned fastening openings  15 . The fastening openings  15  are designed for this purpose as slots having a sufficiently large extent (length).  
         [0033]    As a result, the effect also thus achieved in the case of the exemplary embodiment illustrated in FIGS. 3, 4 a  and  4   b  is that, in the case of a latching connection in which a module holder  2  is connected to the steering wheel body  1  at three fastening points  15 ,  25 , acting on an actuating element  4  in the form of a spring element at just one of the fastening points  15 ,  25  causes the latching connection at all three fastening points  15 ,  25  to be cancelled in such a manner that the module holder can be removed from the steering wheel body  1  by means of a simple pivoting movement S.

Technology Category: 7