Abstract:
The invention relates to a torque transmitting device having a hub arranged in the drive train of a motor vehicle for transmitting torque between a drive unit and a transmission, in particular a turbine wheel hub of a turbine wheel of a torque converter which is coupled to a damper hub with a rotational vibration damper connected in between via a driving plate, in particular of a converter bridge coupling. The invention is operatively arranged such that the rotational vibration damper is equipped with a mechanical stop mechanism that is in effect as soon as a maximum design load on the rotational vibration damper has been exceeded.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This patent application claims priority of German Patent Application No. 10 2005 060 566.4, filed Dec. 17, 2005, which application is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to a torque transmitting device having a hub, in particular a turbine wheel hub of a turbine wheel of a torque converter, arranged in the drive train of a motor vehicle for transmitting torque between a drive unit and a transmission, the torque converter being connected to a damper hub with a torsional vibration damper connected in between via a driving plate, in particular a converter bridge coupling.  
       SUMMARY OF THE INVENTION  
       [0003]     The invention broadly comprises a torque transmitting device having a hub, in particular a turbine wheel hub of a turbine wheel of a torque converter, arranged in the drive train of a motor vehicle for transmitting torque between a drive unit and a transmission, the torque converter being coupled to a damper hub with a torsional vibration damper connected in between via a driving plate of a converter bridge coupling in particular due to the fact that the torsional vibration damper is equipped with a mechanical stop mechanism that is effective as soon as a maximum design load on the torsional vibration damper is exceeded. This yields the advantage that it effectively prevents an overload of the torsional vibration damper. An overload can be defined as any load in excess of the design damper capacity. The protection of the mechanical stop mechanism relates to the force transmitting components of the damper, including the elastic elements that are in effect in the damper.  
         [0004]     A preferred exemplary embodiment comprises a torque transmitting device having a stop mechanism comprising stop fingers that start from the driving plate and protrude into an interspace bordered in the circumferential direction by two stop limiting elements provided on the damper hub. The maximum angle of rotation between the driving plate and the damper hub can be adjusted based on the distances in the circumferential direction between the stop fingers and the respective stop limiting elements.  
         [0005]     In another preferred exemplary embodiment of the torque transmitting device, the stop fingers extend radially inward from a central opening in the driving plate. This allows space to be saved in the axial direction.  
         [0006]     In another preferred exemplary embodiment of the torque transmitting device, the stop limiting elements extend axially from the damper hub. The stop limiting elements are preferably in the form of arcs of a circle.  
         [0007]     In another preferred exemplary embodiment of the torque transmitting device, several stop fingers are distributed uniformly over the circumference of the driving plate. Preferably at least four stop fingers are uniformly distributed over the circumference of the driving plate.  
         [0008]     In another preferred exemplary embodiment of the torque transmitting device, the stop fingers are arranged in the circumferential direction with one stop finger each between two coupling elements leading away from the hub. The coupling elements serve to connect the driving plate to the hub in a rotationally fixed manner. This achieves the result that any overload is directed from the hub directly into the damper hub via the stop fingers of the driving plate.  
         [0009]     In another preferred exemplary embodiment of the torque transmitting device, the coupling elements extend axially away from the hub. The coupling elements are preferably in the form of arcs of a circle.  
         [0010]     In another preferred exemplary embodiment of the torque transmitting device, one coupling finger extends radially inward from the driving plate between two stop fingers. The coupling fingers allow a good force distribution.  
         [0011]     In another preferred exemplary embodiment of the torque transmitting device, the coupling fingers are arranged in the circumferential direction with one each between two coupling elements extending away from the hub. The coupling fingers are shorter than the stop fingers and do not extend into the inner spaces which are limited by two stop limiting elements provided on the damper hub in the circumferential direction.  
         [0012]     In another preferred exemplary embodiment of the torque transmitting device, a damper hub flange is mounted on the damper hub. The two-part design with the damper hub and damper hub flange makes it possible for the two parts to adjust the maximum angle of rotation of the damper when establishing the connection of the damper hub flange to the damper hub. Thus, unlike previous approaches known in the past, it is possible to produce different damper characteristics, e.g., the torque via the angle of rotation, simply by varying the spring elements and without any further geometric change in the damper components.  
         [0013]     In another preferred exemplary embodiment of the torque transmitting device, the damper hub flange is integrally bonded to the damper hub. The damper hub flange is preferably connected to the damper hub by a welded connection, in particular a laser-welded connection. The welded connection is preferably established only after adjusting the maximum angle of rotation of the damper.  
         [0014]     The object of the invention is to create a torque transmitting device as recited in the claims that will have a longer lifetime than traditional torque transmitting devices. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     Additional advantages, features and details are derived from the following description in which an exemplary embodiment is described in detail with reference to the drawings, where:  
         [0016]      FIG. 1  shows a torque transmitting device according to a first exemplary embodiment in a half-sectional view;  
         [0017]      FIG. 2  shows a driving plate with a damper hub and a turbine wheel hub of the torque transmitting device from  FIG. 1  as seen from above; and,  
         [0018]      FIG. 3  shows an enlarged detail from  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]      FIG. 1  shows a part of drive train  1  of a motor vehicle. Hydrodynamic torque converter  6  is arranged between transmission  5  and drive unit  3 , in particular an internal combustion engine, with a crankshaft extending out of it. The crankshaft of internal combustion engine  3  is connected to housing  10  of torque converter  6  in a rotationally fixed manner via a drive plate, which is also referred to as a flex plate.  
         [0020]     Housing  10  of torque converter  6  is rotatable about axis of rotation  12  and is equipped with housing wall  14  near the drive and housing wall  15  at a distance from the drive. Starter gear rim  17  is mounted on housing wall  14  near the drive with the help of connecting sheet metal part  16  extending radially outward. Housing wall  15  at a distance from the drive is combined into a modular unit with pump wheel  20  of hydrodynamic torque converter  6 .  
         [0021]     Turbine wheel  21  which is mounted on turbine wheel hub  22  with the help of rivet connecting elements is arranged between pump wheel  20  and housing wall  14  near the drive.  
         [0022]     Turbine wheel hub  22  is mounted to rotate in relation to input shaft  23  of transmission  5 . Stator  24  is arranged between turbine wheel  21  and pump wheel  20  in a known way. Converter bridge coupling  26  with rotational vibration damper  27  is arranged between turbine wheel  21  and housing wall  14  near the drive, again in a known way. Converter bridge coupling  26  comprises piston  28  mounted to be rotatable and axially displaceable radially to the outside on turbine wheel hub  22 . Piston  28  has on the outside, radially disposed, a friction surface facing internal combustion engine  3  and arranged opposite another friction surface which is provided on the side of housing wall  14  near the drive and facing away from internal combustion engine  3 . Friction plate  29  connected to driving plate  30  in a rotationally fixed mount is arranged between the two friction surfaces.  
         [0023]     Driving plate  30  is connected to damper flange  35  of rotational vibration damper  27  with energy storage elements  33  connected in between, in particular bow springs. Damper flange  35  is integrally bonded to damper hub  38  with the help of welded connection  36 . Damper hub  38  is in turn connected to one end of input shaft  23  of transmission  5  in a rotationally fixed manner on the inside radially.  
         [0024]      FIG. 2  shows turbine wheel hubs  22 , driving plate  30  and damper hub  38 , omitting the other parts in a view of drive unit  3  as seen from above, shown here in the assembled state. Driving plate  30  has essentially the shape of a circular ring plate. On the outside, disposed radially, driving plate  30  has several gear tooth areas  41 ,  42 . Gear tooth areas  20   41 ,  42  serve to connect driving plate  30  to the friction plate ( 29  in  FIG. 1 ) in a rotationally fixed but axially displaceable manner. In addition, driving plate  30  has four windows  44 ,  45  that are distributed uniformly over the circumference and serve to hold the energy storage elements ( 33  in  FIG. 1 ) in a known manner. In addition, the driving plate has multiple through-holes  47 ,  48  which serve to allow the passage or rivet-connecting elements, for example. On the inside,  25  disposed radially, driving plate  30  has central through-hole  49  which is also referred to as an opening.  
         [0025]     Damper hub  38  is arranged concentrically with driving plate  30  and partially in central through-hole  49 . On the inside, disposed radially, damper hub  38  is equipped with internal gear teeth  51 . Internal gear teeth  51  are designed on the inside on essentially tubular damper hub body  53 , of which only ring surface  54  is visible in  FIG. 2 . Outside ring surface  54  radially and concentrically with it, damper hub  38  has another ring surface  55 . However, additional ring surface  55  is arranged with an offset in the axial direction to ring surface  54 . In the view shown here, additional ring surface  55  is offset into the plane of the paper with respect to ring surface  54 .  
         [0026]      FIG. 3  shows the central section of driving plate  30  on turbine wheel hub  22  from  FIG. 2  with damper hub  38  shown on an enlarged scale. Four stop limiting elements  61  through  64  extend axially from ring surface  55  of damper hub  38 . Four stop limiting elements  61  through  64  each have the shape of an arc of a circle and are uniformly distributed over the circumference of ring surface  55 . Essentially arc-shaped interspaces  65 ,  66 ,  67 ,  68  are recessed between two stop limiting elements  61 ,  62 ;  62 ,  63 ;  63 ,  64 ;  64 ,  61 . Stop fingers  71  through  74  protruding into each interspace  65  through  68  extend radially from central through-hole  49  of driving plate  30 . Stop fingers  71  through  74  are attached to driving plate  30  in one piece and are distributed uniformly over the circumference of through-hole  49 . Due to the distance in the circumferential direction between stop fingers  71  through  74  and respective stop limiting elements  61  through  64 , the size of the relative angle of rotation between driving plate  30  and damper hub  38  is defined.  
         [0027]     Turbine wheel hub  22  has ring surface  80  on the outside, disposed radially and concentrically with ring surfaces  54 ,  55  of damper hub  38 , eight coupling elements  81  through  88  extending axially away from the ring surface. Coupling elements  81  through  88  each are in the shape of arcs and are uniformly distributed over the circumference of ring surface  80 . Stop fingers  71  through  74  pass between each of coupling elements  81 ,  82 ,  83 ,  84 ,  85 ,  86 ,  87 ,  88 . In addition, coupling fingers  91  through  94  are arranged between two coupling elements  88 ,  81 ,  82 ,  83 ,  84 ,  85 ,  86 ,  87  and extend radially away from driving plate  30 . Coupling fingers  91  through  94  are arranged so that they are uniformly distributed over the circumference of central through-hole  49  of driving plate  30  in alternation with stop fingers  71  through  74 . However, coupling fingers  91  through  94  are designed to be shorter than stop fingers  71  through  74 . This achieves the result that coupling fingers  91  through  94  do not engage in damper hub  38  but instead are each in contact with one stop limiting element  61  through  64  on the outside, disposed radially. Coupling fingers  91  through  94  and stop fingers  71  through  74  also serve to center driving plate  30  on damper hub  38 .  
         [0028]     The mechanical stop may be used in two directions of rotation, as shown here. However, there is also the possibility of using the mechanical stop in only one direction of rotation. In this case, a load in the other direction of rotation is absorbed by another mechanical stop, e.g., inside the damper.  
       LIST OF REFERENCE NUMERALS  
       [0000]    
       
           1  drive train  
           3  drive unit  
           5  transmission  
           6  torque converter  
           10  housing  
           12  axis of rotation  
           14  housing wall  
           15  housing wall  
           16  connecting sheet metal part  
           17  starter gear rim  
           20  pump wheel  
           21  turbine wheel  
           22  turbine wheel hub  
           23  input shaft  
           24  stator  
           26  converter bridge coupling  
           27  rotational vibration damper  
           28  piston  
           29  friction plate  
           30  driving plate  
           33  energy storage element  
           35  damper flange  
           36  welded connection  
           38  damper hub  
           41  gear tooth area  
           42  gear tooth area  
           44  window  
           45  window  
           47  through-hole  
           48  through-hole  
           39  through-hole  
           51  internal gear teeth  
           53  damper hub body  
           54  ring surface  
           55  ring surface  
           61  stop limiting element  
           62  stop limiting element  
           63  stop limiting element  
           64  stop limiting element  
           65  interspace  
           66  interspace  
           67  interspace  
           68  interspace  
           71  stop finger  
           72  stop finger  
           73  stop finger  
           74  stop finger  
           80  ring surface  
           81  coupling element  
           82  coupling element  
           83  coupling element  
           84  coupling element  
           85  coupling element  
           86  coupling element  
           86  coupling element  
           88  coupling element  
           91  coupling finger  
           92  coupling finger  
           93  coupling finger  
           94  coupling finger