Abstract:
The present invention relates to a torque transmission device in the drive train of a motor vehicle for torque transmission between a drive unit, in particular an internal combustion engine, a gearbox, and with a hydrodynamic torque converter. The torque converter lockup clutch comprises outer lamellae which work together with inner lamellae to connect to a driver plate which is connected to a torsional vibration damper. In order to provide a torque transmission device which has a long service life and can be produced economically, a coupling is fastened to the inner lamella carrier in such a manner that it cannot be turned, and to the radially inner edge area of the driver plate which bounds an annular space in which the radially inner edge area of the driver plate can be moved in the axial direction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This patent application claims priority of German Patent Application No. 10 2005 043 148.8 filed Sep. 10, 2005, which application is incorporated herein by reference. 
   FIELD OF THE INVENTION 
   The present invention relates to a torque transmission device in the drive train of a motor vehicle for torque transmission between a drive unit and a gearbox, having a hydrodynamic torque converter which comprises a driving pump wheel, a driven turbine wheel, and a torque converter lockup clutch. 
   BRIEF SUMMARY OF THE INVENTION 
   In a preferred embodiment, the present invention comprises a torque transmission device wherein the coupling element has an area bent in the form of a step, extending radially outward as seen in cross section. The annular space is disposed between the inner lamella carrier and the coupling element&#39;s bent area is preferably formed by a coupling plate. 
   In a further preferred embodiment, the torque transmission device includes a step rivet fastened to the inner lamella carrier, the step rivet includes a fastening section with a small outer diameter and a bearing section with a large outer diameter whose length is greater than the thickness of a radially inner edge area of the driver plate which includes a through hole through which the bearing section extends. Preferably, the driver plate comprises on its radially inner area several through holes, which are distributed uniformly over the circumference of the radially inner edge area. A step rivet fastened to the inner lamella carrier is assigned to each of the through holes. 
   In a further preferred embodiment, the invention comprises a torque transmission device wherein, the driver plate is pre-braced against the inner lamella carrier with the aid of a plate spring. Thereby, a definite positional alignment of the driver plate is ensured. 
   In a further preferred embodiment, the invention comprises a torque transmission device wherein the driver plate comprises at least one flexible intermediate area between a radially inner edge area and a radially outer edge area. The flexible intermediate area makes possible a movement of the radially inner edge area relative to the radially outer edge area of the driver plate in the axial direction and conversely. 
   In a further preferred embodiment, the invention comprises a torque transmission device wherein the driver plate comprises a coupling area bent at an angle extending radially outward. The coupling area connects, in such a manner that it cannot be turned but can be moved in the axial direction, to the input part of the torsional vibration damping device. The connection which is such that turning is impossible is, for example, made possible by coupling fingers, each of which has two stops between which the input part of the torsional vibration damping device can be moved back and forth in the axial direction. 
   In a further preferred embodiment, the invention comprises a torque transmission device including a plate spring pre-loaded in the axial direction which is disposed between the driver plate and the input part of the torsional vibration damping device. Thereby, a definite positional alignment of the driver plate or the input part of the torsional vibration damping device is ensured. 
   The object of the present invention is to provide a torque transmission device, by which the torque transmission device has a long service life and can be produced economically. 
   The object of the present invention is achieved in a torque transmission device in the drive train of a motor vehicle for torque transmission between a drive unit, in particular an internal combustion engine with a drive shaft, in particular a crankshaft, and a gearbox with at least one gearbox input shaft. In addition, the drive train includes a hydrodynamic torque converter which comprises a driving pump wheel, which is connected, via a housing and in such a manner that it cannot be turned, to the drive shaft of the drive unit, and a driven turbine wheel which is disposed, in such a manner that it can be turned, in the housing, and with a torque converter lockup clutch which can be actuated by a piston and comprises outer lamellae which work together with inner lamellae which are mounted on an inner lamella carrier which is connected, in a manner such that it cannot be turned, to a driver plate which in turn is connected, in a manner such that it cannot be turned, to an input part of a torsional vibration damping device. 
   The objective is realized by the inner lamella carrier coupling element which is connected, in such a manner that it cannot be turned, to the radially inner edge area of the driver plate and bounds an annular space in which the radially inner edge area of the driver plate can be moved in the axial direction. The coupling element can also be connected as one piece with the inner lamella carrier. The connection between the coupling element and the driver plate, the connection being fixed against turning, is preferably realized by an inner toothing on the driver plate which is in engagement with an outer toothing of the coupling element. Through the coupling element, axial forces occurring in the torque converter during driving are stayed in a simple manner. Thereby, undesirable plastic deformation of structural parts can be prevented. Furthermore, the undesirable friction caused by the axial forces can be minimized. 
   Further advantages, features, and details of the invention result from the following description, in which an exemplary embodiment is described in detail with reference to the drawing. The features cited in the claims and in the description may be significant to the present invention individually or in any arbitrary combination. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
       FIG. 1  is a torque transmission device in longitudinal section; 
       FIG. 2  is an embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 ; 
       FIG. 3  is a further embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 ; 
       FIG. 4  is another embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 ; 
       FIG. 5  is yet another embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 ; 
       FIG. 6  is a further embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 ; 
       FIG. 7  is another embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 ; and, 
       FIG. 8  is yet another embodiment of axial forces occurring during driving that can be compensated with the present invention torque transmission device of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred embodiment, it is to be understood that the invention as claimed is not limited to the preferred embodiment. 
   Furthermore, it is understood that this invention is not limited to the particular methodology, materials, and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
   Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. 
   In  FIG. 1  a part of drive train  1  of a motor vehicle is represented. Hydrodynamic torque converter  8  is disposed between drive unit  3 , in particular an internal combustion engine from which a crankshaft goes out, and gearbox  5 . Torque converter  8  is disposed so as to be concentric to axis of turning  10  and comprises housing  12  with housing wall  15  near to the drive and housing wall  16  far from the drive. Housing wall  15  is near drive unit  3 , which is connected in such a manner that it cannot be turned. Housing wall  16  is far from drive unit  3 , which is combined in one structural unit with pump wheel  18  of hydrodynamic torque converter  8 . 
   Between pump wheel  18  and housing wall  15 , turbine wheel  20  is disposed radially inwards to turbine wheel hub  21 . Guide wheel  22  is disposed between turbine wheel  20  and pump wheel  18 , which is guided via free wheel  24  on running wheel hub  25 , which is disposed via a toothing on a tubular piece fixed relative to the housing. 
   Turbine wheel hub  21  is disposed, in a manner such that it can be turned, on torsional vibration damping device hub  28  of torsional vibration damping device  30 . Torsional vibration damping device hub  28  is connected, in such a manner that it cannot be turned, to a gearbox input shaft (not represented). Radially outwards, turbine wheel hub  21  is connected, in such a manner that it cannot be turned, to first input part  31  of torsional vibration damping device  30 . First input part  31  of torsional vibration damping device  30  is coupled in a known manner via energy storage elements  34 ,  35  with output part  32  of torsional vibration damping device  30 . Output part  32  of torsional vibration damping device  30  is fastened radially inwards to torsional vibration damping device hub  28 . 
   Output part  32  is coupled in a known manner via energy storage elements  34 ,  35  to second input part  37  of torsional vibration damping device  30 . Second input part  37  of torsional vibration damping device  30  is formed in the manner of a flange and connected radially outwards to driver element  41 . Driver element  41  is formed by driver plate  42  from which driver fingers go out radially, engage in corresponding recesses, and are hollowed out in second input part  37 . Radially inwards, driver plate  42  is connected, with the aid of coupling element  46 , in such a manner that it cannot be turned, to inner lamella carrier  44  of lamella coupling  50 . Coupling element  46  is fastened with the aid of rivet connections  48  to inner lamella carrier  44 . Inner lamella carrier  44  carries inner lamellae, which work together in a known manner with outer lamellae and are mounted on outer lamellae carrier  52 . Outer lamellae carrier  52  is fastened to housing wall  15  of housing  12 , the housing wall being the wall near to the drive. Lamella coupling  50  can be actuated by piston  54 , which can be moved back and forth in the axial direction between housing wall  15  near to the drive and the lamellae of lamella coupling  50 . Piston  54  is disposed, in a manner such that it can be turned, on hub part  56 . 
   During driving, axial forces occur in hydrodynamic torque converter  8 , which according to the present invention are compensated via individual components of torsional vibration damping device  30  or via driver element  41 . Thereby, impermissible friction at these parts, as well as an undesirable plastic deformation of these parts, is prevented. The compensation of the axial forces can be accomplished by various measures, as is indicated by circles  61  through  64  which enclose the details which are represented on an enlarged scale in  FIGS. 2 through 8 . 
   In  FIG. 2 , details  61  and  62  from  FIG. 1  are represented on an enlarged scale. Driver plate  42  is connected, at its radially inner edge area  66  and with the aid of coupling element  46 , in such a manner that it cannot be turned, to inner lamella carrier  44 . Coupling element  46  is formed by a metal plate, which comprises, radially outwards, area  67  bent in the form of a step. Area  67 , bent in the form of a step, bounds an annular space in which radially inner edge area  66  of driver plate  42  is received, in such a manner that it can be moved back and forth in the axial direction, as is indicated by double arrow  68 . 
   In  FIG. 3 , an additional embodiment example of detail  61  from  FIG. 1  is represented. Driver plate  42  can also comprise radially inner edge area  69 , which is fastened with the aid of step rivet  70  to inner lamella carrier  44 . Step rivet  70  comprises fastening section  71  whose extension in the axial direction corresponds to the thickness of inner lamella carrier  44 . Moreover, Step rivet  70  comprises bearing section  72  that has a greater outer diameter than fastening section  71 . The extension of bearing section  72  in the axial direction is greater than the thickness of radially inner edge area  69  of driver plate  42 . Thereby it is ensured that radially inner edge area  69  of driver plate  42  can be moved back and forth in the axial direction on bearing section  72 , as is indicated by double arrow  73 . 
   In  FIG. 4 , detail  64  from  FIG. 1  is represented on an enlarged scale. Radially outwards, driver plate  42  has coupling area  75  bent at an angle. Coupling area  75  bent at an angle comprises a plurality of fingers which engage in recesses and are hollowed out radially outwards in second input part  37  of the torsional vibration damping device. The fingers, which are also designated as coupling fingers, each comprise, in the axial direction, two stops between which second input part  37  can be moved back and forth in the axial direction, as is indicated by double arrow  76 . 
   The embodiment examples represented in  FIGS. 2 through 4  have no definite positional alignment of the parts, and therefore can be moved relative to one another. In  FIGS. 5 through 7 , the embodiment examples of  FIGS. 2 through 4  are provided with a definite positional alignment. In the embodiment example represented in  FIG. 5 , plate spring  77  is braced between radially inner edge area  66  of driver plate  42  and area  67 , which is a part of coupling element  46  and is bent in the form of a step. In the embodiment example represented in  FIG. 6 , plate spring  78  is braced between step rivet  70  and radially inner edge area  69  of driver plate  42 . In the embodiment example represented in  FIG. 7 , plate spring  79  is braced between second input part  37  and driver plate  42 . 
   In  FIG. 8 , detail  63  of  FIG. 1  is represented on an enlarged scale. In  FIG. 8 , driver plate  42  can have flexible intermediate area  80  between a radially inner edge area and a radially outer edge area, the intermediate area, as is indicated by double arrows  81  and  82 , enabling movement of the radially inner edge area relative to the outer edge area of driver plate  42  in the axial direction and conversely. 
   Thus, it is seen that the objects of the present invention are efficiently obtained, although modification and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention. 
   REFERENCE NUMBERS 
   
       
         1  Drive train 
         2  Drive unit 
         5  Gearbox 
         8  Hydrodynamic torque converter 
         10  Axis of turning 
         12  Housing 
         15  Housing wall near to the drive 
         16  Housing wall far from the drive 
         18  Pump wheel 
         20  Turbine wheel 
         21  Turbine wheel hub 
         22  Guide wheel 
         24  Free wheel 
         25  Running wheel hub 
         28  Torsional vibration damping device hub 
         30  Torsional vibration damping device 
         31  First input part 
         32  Output part 
         34  Energy storage element 
         35  Energy storage element 
         37  Second input part 
         41  Driver element 
         42  Driver plate 
         44  Inner lamella carrier 
         46  Coupling element 
         48  Rivet connection 
         50  Lamella coupling 
         52  Outer lamella carrier 
         54  Piston 
         56  Hub part 
         61  Detail 
         62  Detail 
         63  Detail 
         64  Detail 
         66  Radially inner edge area 
         67  Area bent in the form of a step 
         68  Double arrow 
         69  Radially inner edge area 
         70  Step rivet 
         71  Fastening section 
         72  Bearing section 
         73  Double arrow 
         75  Coupling area bent at an angle 
         76  Double arrow 
         77  Plate spring 
         78  Plate spring 
         79  Plate spring 
         80  Flexible intermediate area 
         81  Double arrow 
         82  Double arrow