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CROSS-REFERENCE TO A RELATED APPLICATION 
     This application is a National Phase Patent Application of International Patent Application Number PCT/DE2005/002279, filed on Dec. 13, 2005, which claims priority of German Patent Application Number 10 2004 063 514.5, filed on Dec. 27, 2004. 
     BACKGROUND 
     The invention relates to a window pane for a motor vehicle. 
     Such a window pane consisting of plastic is provided for closing a pane opening (in particular defined by means of a window frame) of a motor vehicle, and may be moved by means of a window lifter out of the pane opening and brought again into its closed position in the pane opening. The window pane comprises a pane element enclosed by an outer edge as well as a device arranged on the pane element for coupling the window pane to an adjusting mechanism of the window lifter. 
     In this case, the term ‘window frame’ is generally understood to be a restriction to a window opening in a motor vehicle, which may be closed by a window pane provided to this end (which is adjustable by means of a window lifter). In this case, the restriction is, for example, arranged on a motor vehicle door (in particular a folding door or sliding door) or a restriction arranged on an immovable region of the bodywork of a motor vehicle, defining (and at least partially enclosing) a pane opening denoted as a frame. With so-called frameless vehicle doors which are used, in particular, with convertible vehicles, the associated window frame is formed by a region of the restriction of the door opening on the bodywork side, which may be closed by the corresponding vehicle door. The part of the restriction of the door opening which defines, according to its intended purpose, the window pane provided on the vehicle door when the vehicle door is closed, is considered as the window frame (in the case of an adjustable window pane, a window pane in its closed position is taken as a starting point). 
     It is generally known in the prior art to fasten a drive element to a window pane, in particular to the lower edge thereof, via which the window pane is connected to the lifting mechanism of an associated window lifter, for example to a cable of a tractive means window lifter or to a lever arm of an arm window lifter. 
     SUMMARY 
     The object of the invention is to provide a window pane for motor vehicles which is further improved with regard to its connection to an associated motor vehicle window lifter. 
     Accordingly, for coupling the window pane to the adjusting mechanism of a window lifter, a guide region is integrally formed on the pane element which projects from a surface of the pane element and via which the window pane engages positively and longitudinally displaceably with guide means of the adjusting mechanism. 
     Said guide region is arranged and configured, in particular, such that when the window lifter is engaged in associated guide means it prevents a pivoting of the window pane about an axis extending perpendicular to the pane plane. 
     The guide region of the window pane may, on the one hand, be formed from the same material as the remaining pane element of the window pane or may be formed on the pane element from a different material, according to the so-called two-component technique. 
     So that a pivoting of the window pane is prevented about an axis extending perpendicular to the pane plane, when the window pane is in engagement via its guide region with associated guide means of the window lifter, the guide region comprises at least two stops spaced apart from one another transversely to the direction of adjustment of the window pane, via which the window pane is able to be supported on associated guide means. With such stops, moreover, a pivoting of the window pane about an axis extending parallel to the direction of adjustment may also be prevented. 
     According to an exemplary embodiment of the invention, the guide region comprises an undercut into which the associated guide means of the window lifter are able to engage. As a result, in addition to a pivoting of the window pane about an axis extending perpendicular to the pane plane, a slipping of the window pane perpendicular to the pane plane may also be prevented. 
     According to an exemplary embodiment of the invention the guide region is arranged on the lower edge and/or in the immediate vicinity of the lower edge of the window pane—relative to the state of the window pane installed in a motor vehicle. As a result, a particularly long lever arm is provided for supporting the window pane against pivoting. 
     According to one exemplary embodiment, the guide region comprises a projection extending in the direction of adjustment of the window pane for acting in associated guide means, the lateral faces of the projection opposing one another perpendicular to the direction of adjustment forming stops, by means of which a pivoting of the window pane, in particular about an axis extending transversely to the pane plane, is able to be prevented. 
     According to a further exemplary embodiment, the guide region of the window pane comprises a receiver (recess) extending in the direction of adjustment, into which the associated guide means are able to engage, lateral defining surfaces of the receiver spaced apart from one another perpendicular to the direction of adjustment forming corresponding stops. 
     The guide regions may be arranged in a portion of the window pane which is not provided for closing a window opening, for example on an extension of the pane element which projects from the lower edge of the pane element—relative to the installed state of the window pane in a motor vehicle. 
     Moreover, a receiver may be configured on the window pane, via which the window pane may be connected to a force transmission means of the lifting mechanism, which transmits the adjusting force generated by a drive of the window lifter to the window pane to be adjusted. In this case, said receiver may, for example, be a nipple chamber which is provided for positively receiving a cable nipple of a tractive means window lifter, in order to transmit the forces acting on the tractive means during the operation of the window lifter to the window pane to be adjusted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the invention will become apparent from the following description of embodiments with reference to the figures, in which: 
         FIG. 1   a  shows a door assembly for a motor vehicle with an adjustable window pane, into which a guide region for guiding the window pane in a direction of adjustment is integrally incorporated. 
         FIG. 1   b  shows a cross section through the guide region of the window pane of the door assembly of  FIG. 1   a.    
         FIG. 2   a  shows a modification of the door assembly of  FIG. 1   a.    
         FIG. 2   b  shows a modification of the cross section of  FIG. 1   b.    
         FIG. 2   c  shows a modification of the cross section of  FIG. 1   b.    
         FIG. 3   a  shows a second modification of the door assembly of  FIG. 1   a.    
         FIG. 3   b  shows a cross section through the door assembly of  FIG. 3   a  in the guide region of the window pane. 
         FIG. 4   a  shows a third modification of the door assembly of  FIG. 1   a.    
         FIG. 4   b  shows a cross section through the door assembly according to  FIG. 4   a  in the guide region of the window pane. 
         FIG. 5   a  shows a door assembly according to  FIG. 1   a.    
         FIG. 5   b  shows a cross section through the door assembly of  FIG. 5   a  in a receiver region of the window pane in which a force transmission means of the window lifter is fixed. 
     
    
    
     DETAILED DESCRIPTION 
     A door assembly of a motor vehicle door is shown in  FIG. 1   a , which comprises a door body  3  with a window frame  2 , as well as a displaceably mounted window pane  1  with an associated window lifter  4 . 
     By means of two lateral frame portions  21 ,  22  spaced apart from one another—relative to the state installed in a motor vehicle—as well as an upper frame portion  23  on the roof side connecting said frame portions, the window frame  2  defines a pane opening  20  which may be closed by the pane element  10  of the adjustable window pane  1 . The pane element  10  of the adjustable window pane  1  is firstly defined by two edges  11 ,  12  spaced apart from one another along the longitudinal axis of the vehicle x, as well as further by an upper edge  13  and a lower edge  14  at a distance therefrom along the vertical vehicle axis z, which comprises an extension  14   a  for connecting the window pane to the window lifter  4 . 
     Between the one lateral frame portion  22  and a curved region of the upper frame portion  23  of the window frame  2  a (non-adjustable) triangular window  25  is additionally arranged, which may be integrally formed on the window frame  2  when using plastic as a material for said window frame  2 . By using the so-called two-component technique during the manufacture of the window frame  2 , an opaque, for example non-transparent, plastic component for manufacturing the frame portions  21 ,  22 ,  23  may be combined in this case with a transparent plastic component for manufacturing the triangular window  25 . 
     A window lifter  4  serves for adjusting the window pane  1  in a direction of adjustment z, which coincides with the vertical vehicle axis, the components of said window lifter being arranged on a region of the door body  3  located below the window opening  20 . Said region of the door body  3  is generally formed by a door outer skin and a door inner skin, which enclose a hollow space therebetween denoted as a door shaft. In this case, the door outer skin defines an outer design surface of the motor vehicle door, whilst the door inner skin—relative to the state of the door installed in a motor vehicle—faces the vehicle interior. 
     The window lifter  4  comprises a drive  40 ,  41  formed by a drive motor  40  and a gear mechanism  41  downstream thereof, with a rotatably mounted cable drum about which a tractive means  42  of the window lifter, formed by a cable, is wound, and which during operation of the motor  40  is rotated in the one or the other direction. The tractive means  42  is guided by means of deflection elements  43 , in particular in the form of guide pulleys, in a segment along a guide rail  44  extending in the direction of adjustment z of the window pane and serves as force transmission means for transmitting an adjusting force generated by the drive  40 ,  41  to the window pane  1  to be adjusted. The tractive means  42  serving as force transmission means, the associated deflection elements  43  and the guide rail  44  thus form a lifting mechanism, by means of which it is possible to raise and lower the window pane  1  by means of the adjusting force generated by the drive  40 ,  41 . 
     To this end, according to  FIGS. 5   a  and  5   b , a receiver region  140   a  with a nipple chamber  142   a  is formed on an extension  14   a  projecting from the lower edge  14  of the window pane  1 , which chamber positively receives a cable nipple  42   a  of the tractive means  42 . 
     For the defined guidance of the window pane  1 , said window pane according to  FIGS. 1   a  and  1   b  is in defined engagement with the guide rail  44  of the window lifter  4 , via a guide region  16 ,  17 . The guide rail  44  is, in this case, preferably integrally formed on a support  30  consisting of plastic which forms a component of the door inner skin of the door body  3 , as known for example from DE 199 44 965 A1. 
     The guide rail  44  serving as guide means for guiding the window pane  1  in the direction of adjustment z of the window lifter  4  is, according to  FIG. 1   b , formed by a stepped guide rail region  46 ,  47 , projecting from the support element serving as a door module support, in a direction y perpendicular to the pane plane of the window pane  1 . Said guide rail region forms a top surface  46  facing the window pane  1  from which two stops  47   a  spaced apart from one another in the pane plane perpendicular to the direction of adjustment z are bent back, extending parallel to one another, to which respectively one shoulder  47  extending parallel to the pane plane is attached. 
     A through a receiver  16 ,  17  extending in the direction of adjustment z of the window pane  1  is associated with said guide rail region  46 ,  47  of the window lifter  4 , and which is located in front of the surface O 2  of the window pane  1  to be adjusted facing the vehicle interior, i.e. on the side facing away from the outer surface O 1  of the window pane  1 . Said receiver is formed by two projections  17  spaced apart from one another perpendicular to the direction of adjustment z of the window pane, formed integrally on the window pane  1  and projecting from the inner surface O 2  thereof, and which extend respectively in the direction of adjustment z of the window pane, as well as by a bottom surface  16  connecting the two projections  17 . Each of the two projections  17  defines a stop  17   a  on the edge side cooperating with one respective opposing lateral stop  47   a  of the guide rail  44 , whereby a pivoting of the window pane  1  relative to an axis y extending perpendicular to the pane plane is prevented. Additionally, the cooperation of the bottom surface  16  of the recess  16 ,  17  on the pane side with the top surface  46  of the guide rail  44  extending parallel to the pane plane and facing the window pane  1  also prevents a pivoting of the window pane  1  about an axis extending parallel to the direction of adjustment z. 
     By means of this guide region  16 ,  17  which is formed in the extension  14   a  projecting downward from the lower edge  14  of the window pane  1 , the window pane  1  may be guided in a defined manner along the guide rail  44  of the window lifter  4 , a pivoting of the window pane both about an axis y extending perpendicular to the pane plane and about an axis z extending parallel to the direction of adjustment being prevented. 
     A pivoting of the window pane about the other axis x located in the pane plane, extending perpendicular to the direction of adjustment z (longitudinal axis of the vehicle relative to the state of the door assembly installed in a motor vehicle) is prevented by the guidance of the window pane  1  with its lateral edges  11 ,  12  in associated frame portions  21 ,  22  of the window frame  2 . 
     A development of the door assembly shown in  FIGS. 1   a  and  1   b  is shown in  FIGS. 2   a  and  2   b , the difference being that the guide region  16 ,  17  formed on the window pane  1  forms with the inner stops  17   b  of the projections  17  an undercut, which is engaged from the rear by the opposing lateral stops  47   b  of the guide rail  44  adapted thereto. By this cooperation of the guide region  16 ,  17  of the window pane  1  with the guide rail  44 , a movement of the window pane  1  in a direction y perpendicular to the pane plane  1  and thus also a pivoting of the window pane  1  about the axis x extending perpendicular to the direction of adjustment z in the pane plane is additionally prevented. 
       FIG. 2   c  shows in cross section a modification of the guide regions and guide rails of  FIGS. 1   b  and  2   b , on the lower extension  14   a  of the window pane  1  a projection  18  being integrally formed as a guide region, which forms two lateral stops  18   a  spaced apart from one another in the pane plane, as well as a top surface  19  extending parallel to the pane plane and which projects in the direction of adjustment z of the window pane  1  from the inner surface O 2  of the window pane  1  in the direction of the guide rail  44 . A guide rail  44  cooperates with said guide region  18 ,  19  of the window pane  1 , and which in turn is formed integrally on a support element  30  and forms a receiver  48 ,  49  for the guide region  18 ,  19  of the window pane  1 . Said receiver  48 ,  49 , extending in the direction of adjustment z of the window pane  1 , is defined by two stops  48   a  spaced apart from one another perpendicular to the direction of adjustment z, along the pane plane, which are formed by one respective projection  48  of the guide rail  44 , as well as by a bottom surface  49  connecting the two projections  48 . The cooperation of the lateral stops  18   a  on the window side, with the opposing lateral stops  48   a  on the guide rail side, which substantially bear against one another—except for a small amount of clearance—prevents a pivoting of the window pane about an axis y extending perpendicular to the pane plane and the cooperation of the bottom surface  49  of the recess  48 ,  49  on the guide rail side with the top surface  19  of the guide region  18 ,  19  on the window pane side additionally counteracts a pivoting about an axis extending parallel to the direction of adjustment z. 
     A development of the door assembly of  FIGS. 1   a  and  1   b  is shown in  FIGS. 3   a  and  3   b , a cross member Q extending on the door body  3  in the region of the door casing and which is intended to increase the stiffness of the door body  3  as a side impact member, in particular in the event of a crash. A support element, for example in the form of a pillar P, is arranged on said side impact member Q and which may support the window pane  1  in the lowered state on its side facing away from the guide rail  44 , i.e. its outer surface O 1 . As a result, a movement of the window pane in the direction y transversely to the pane plane, and/or a pivoting of the window pane  1  about an axis x extending in the pane plane transversely to the direction of adjustment z is prevented. The support element P thus preferably consists of plastic, in order to avoid scratching the pane surface O 1  facing said support element. 
     Finally, a modification of the door assembly of  FIGS. 1   a  and  1   b  is shown in  FIGS. 4   a  and  4   b , in which the guide region  16 ,  17  formed integrally on the window pane  1 , namely on the lower extension  14  thereof, consists of a different material from the pane element  10  thereof. This may be achieved by using the so-called two-component technique when manufacturing the window pane  1 , as the pane element  10  thereof and the guide region  16 ,  17  thereof are formed from different plastics. 
     In the aforementioned embodiments, the window pane to be adjusted may always be displaced in a direction z which—relative to the state installed in a motor vehicle—substantially coincides with the vertical vehicle axis of a motor vehicle. The arrangement disclosed above with reference to the FIGS. is, however, not in any way restricted to such cases in which the window pane may only be adjusted in a straight line or more specifically only along a vehicle axis (namely the vertical vehicle axis). However, the adjustment of the window pane along curved paths is also expressly intended to be included, so that the direction of adjustment of the window pane is altered locally along its adjustment path. The vertical vehicle axis z thus corresponds to a main direction of adjustment, corresponding to a raising of the window pane into the associated window opening and/or a lowering of the window pane out of the window opening. However, further components of motion in other spatial directions may always be superimposed on such a raising or lowering of the window pane in the vertical direction z.

Summary:
A window pane for a motor vehicle including plastic for closing a pane opening of a motor vehicle and which is moveable with a window lifter out of the pane opening includes a pane element enclosed by an outer edge and a device provided on the pane element for coupling the window pane to an adjusting mechanism of the window lifter. For coupling the window pane to the adjusting mechanism of the window lifter, a guide region is formed on a surface of the pane element via which the window pane is engageable with a guide device of the adjusting mechanism, displaceable in a direction of adjustment. The guide region forms at least one stop, which counteracts a pivoting of the window pane about an axis extending perpendicular to a plane of the window pane.