Abstract:
A torsional vibration damping disk having receiving spaces for spring elements, particularly for bow spring elements, which are each arranged between two limit stop areas in the peripheral direction. In order to create a torsional vibration damping disk, which is producible easily and cost-effectively, the spring elements are each clamped with a slight pretension between two limit stop areas.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This patent application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/689,456, filed Jun. 10, 2005, which application is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention relates to a torsional vibration damping disk comprising receiving spaces for spring elements, particularly for bow spring elements, which are each arranged between two limit stop areas in the peripheral direction. The invention also relates to a hydrodynamic torque converter comprising the torsional vibration damping disk described at the onset. The invention further relates to a method for the production of said torsional vibration damping disk described at the onset. 
   BACKGROUND OF THE INVENTION 
   A torsional vibration damping disk having receiving spaces for bow spring elements, which are each arranged between two limit stop areas in the peripheral direction is known from U.S. Pat. No. 6,675,457. In the production of the known torsional vibration damping disk, the spring elements are inserted into the preformed receiving spaces. After the insertion of the spring elements, the sheet metal material delimiting the receiving spaces is further deformed around the spring elements in a manner that prevents the spring elements from falling out of the receiving spaces. 
   SUMMARY OF THE INVENTION 
   It is the object of the invention to create a torsional vibration damping disk comprising receiving spaces for spring elements, particularly for bow spring elements, which are each arranged between two limit stop areas in the peripheral direction, wherein said torsional vibration damping disk has a simple design and can be produced cost-effectively. 
   The object is attained in a torsional vibration damping disk comprising receiving spaces for spring elements, particularly bow spring elements, which are each arranged between two limit stop areas in the peripheral direction by clamping each of the spring elements with a slight pretension between two limit stop areas. The slight pretension of the spring elements prevents them from falling out of the receiving spaces without causing the sheet metal material delimiting the receiving spaces from further deforming around the spring elements after the insertion of the latter. 
   The object of the invention is also attained in a torsional vibration damping disk comprising receiving spaces for spring elements, particularly bow spring elements, which are each arranged between two limit stop areas in the peripheral direction by deforming the torsional vibration damping disk radially inside the spring elements in at least one place in such a way that the deformed area prevents the associated spring element from falling out. The deformed area can be provided as an alternative or in addition to the pretensioning, described at the onset, of the spring elements. The associated spring element preferably rests partially against the deformed area in the installed state. 
   In a preferred embodiment, the torsional vibration damping disk includes a deformed area comprising a lug, which is bent out of the torsional vibration damping disk. The lug is formed, for example, by a substantially U-shaped incision into the torsional vibration damping disk. 
   In another preferred embodiment, the torsional vibration damping disk includes a deformed area comprising an elevation in the torsional vibration damping disk. The shape of the elevation is preferably adapted to the associated spring element. 
   The invention also relates to a hydrodynamic torque converter comprising the torsional vibration damping disk described at the onset. 
   In a method for the production of the torsional vibration damping disk described at the onset, the torsional vibration damping disk comprising receiving spaces for spring elements, particularly for bow spring elements, which are each arranged between two limit stop areas in the peripheral direction, the object specified above is attained by clamping the spring elements with a low pretension between the limit stop areas. The pretensioning of the spring elements reliably prevents them from falling out of the receiving spaces without requiring the sheet metal material delimiting the receiving spaces to be further deformed around the spring elements after the insertion of the latter. 
   The object specified above is also attained in a method for the production of a torsional vibration damping disk comprising receiving spaces for spring elements, particularly for bow spring elements, which are each arranged between two limit stop areas in the peripheral direction, by deforming the torsional vibration damping disk radially inside the receiving spaces for the spring elements in at least one place in such a way that the deformed area prevents a spring element arranged between the limit stop areas from falling out. In this case, the spring element need not be pretensioned. The deformation can be carried out as an alternative or in addition to the pretensioning of the spring elements described at the onset. The associated spring element preferably rests against the deformed area in the installed state. 
   In a preferred embodiment of the method, the torsional vibration damping disk is deformed before the insertion of the spring elements. The advantage of this is that the torsional vibration damping disk can be subjected to a heat treatment before the insertion of the spring elements. After the heat treatment the torsional vibration damping disk no longer has to be deformed. 
   In another preferred embodiment of the method, the torsional vibration damping disk is deformed after the insertion of the spring elements. This simplifies the insertion of the spring elements. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Additional advantages, features, and details of the invention are specified in the following description in which different example embodiments are described in detail with reference to the drawings. The features mentioned in the claims and in the description can thereby be essential to the invention either individually or in any combination thereof. The drawing illustrates: 
       FIG. 1  illustrates the upper half of a longitudinal section of a hydrodynamic torque converter comprising an inventive torsional vibration damping disk; 
       FIG. 2  illustrates the top view of the torsional vibration damping disk alone; 
       FIG. 3  illustrates the view of a section along the line III-III shown in  FIG. 2 ; 
       FIG. 4  is an enlarged illustration of a detail IV shown in  FIG. 3 ; 
       FIG. 5  is a perspective illustration of the torsional vibration damping disk before the insertion of the bow springs; 
       FIG. 6  illustrates the torsional vibration damping disk shown in  FIG. 5  after the insertion of the bow springs; 
       FIG. 7  illustrates the torsional vibration damping disk shown in  FIG. 6  after the bending out of the lugs; and, 
       FIG. 8  illustrates a similar torsional vibration damping disk as in  FIG. 7  in accordance with another example embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates the upper half of a longitudinal section of hydrodynamic torque converter  1 , which is arranged concentrically to rotation axis  2 . Torque converter  1  is arranged in the drive train (not illustrated) of a motor vehicle between internal combustion engine  3  and automatic gearbox  7 . Internal combustion engine  3  comprises a driven shaft, for example, a crankshaft, which is connected non-rotatably to housing  4  of torque converter  1 . Housing  4  comprises housing wall  5  located close to the drive and housing wall  6  located far from the drive. Housing wall  5  located close to the drive is connected in its radially inner area in one piece to hub part  8 , which is guided radially using an attachment in the flywheel or in the crankshaft of the internal combustion engine. 
   Housing wall  6  of torque converter  1 , the housing wall being located far from the drive, is combined with pump wheel  10  to form one structural unit. Turbine wheel  11  is arranged between pump wheel  10  and housing wall  5  located close to the drive, wherein turbine wheel  11  is permanently connected to turbine wheel hub  12 , which is arranged using a toothing on a gearbox input shaft (not illustrated). Guide wheel  13  is arranged between turbine wheel  11  and pump wheel  10 , wherein the guide wheel is guided using freewheel  15  on guide wheel hub  14 , which in turn is fitted using a toothing on a tube section (not illustrated), which is fixed to the housing. 
   Piston  18  of converter lockup clutch  16  is arranged between turbine wheel  11  and housing wall  5  located close to the drive. Piston  18  comprises radially inwards collar  19 , which points away from gearbox  7  and which is supported axially displaceably on turbine wheel hub  12  and is sealed in relation to this hub by sealing  20 . Towards internal combustion engine  3 , which is also referred to as a drive, piston  18  comprises friction surface  22 , which is arranged opposite to friction surface  24 , which is provided on the side of housing wall  5  located close to the drive, the side being turned away from internal combustion engine  3 . Intermediate plate  25  is arranged between friction surfaces  22  and  24 , wherein the intermediate plate is non-rotatably connected to piston  18 . Another intermediate plate  27  is arranged in turn between intermediate plate  25  and friction surface  22 , wherein intermediate plate  27  is non-rotatably connected to housing wall  5 , located close to the drive. 
   Piston  18  simultaneously forms the input part of torsional vibration damper  29 , which is connected between piston  18  and turbine wheel  11 . Torsional vibration damper  29  comprises several receiving spaces for energy storage elements. In the sectional view illustrated in  FIG. 1 , receiving space  30  can be seen, in which energy storage element  31  is received. An arm angled radially outwards from piston  18  towards gearbox  7  engages in energy storage element  31 . Receiving space  30  is embodied in torsional vibration damping disk  32 , which is fixed radially inwards with the help of riveted joints  33  to turbine wheel hub  12 . Lug  34  bent out of torsional vibration damping disk  32  prevents energy storage element  31  from falling out of receiving space  30 . 
     FIG. 2  illustrates a top view of torsional vibration damping disk  32 . Torsional vibration damping disk  32  substantially has the shape of a circular disk, of which radially outer edge  36  is deflected in order to form receiving spaces for energy storage elements  31 ,  42 ,  43 , and  44 . The cross-section of deflected edge  36  has the shape of a circular arc, which stretches over less than 180 degrees in its peripheral direction. This enables an easy insertion of energy storage elements  31 ,  42  to  44 . 
   Energy storage elements  31 ,  42  to  44  are curved helical compression springs, which are also referred to as bow springs. Bow springs  31 ,  42  to  44  are each arranged between two limit stops  45  and  46 . According to one aspect of the present invention, bow spring  31  is clamped with a low pretension between limit stops  45  and  46 . In a similar manner the other bow springs  42  to  44  can be clamped between the associated limit stops. Limit stops  45  and  46  are each provided on deformed areas  47 ,  48  of torsional vibration damping disk  32 . 
   In its radially inner area, torsional vibration damping disk  32  comprises ring flange  50  having several throughholes  51 ,  52 . Throughholes  51 ,  52  are arranged for passing riveted joints ( 33  in  FIG. 1 ). As an alternative or in addition to the pretensioning of bow spring  31 , lug  34  is bent out of torsional vibration damping disk  32  radially inside bow spring  31 . Lug  34  is substantially formed from a C-shaped incision into torsional vibration damping disk  32 . 
     FIG. 3  illustrates the view of a section along the line III-III shown in  FIG. 2 . It is apparent in the sectional view that the free end of lug  34  is arranged slightly below bow spring  31  in such a way that the latter cannot fall out of the receiving space arranged inside deflected edge  36 . A detail IV shown in  FIG. 3  is illustrated in an enlarged form in  FIG. 4 . 
     FIG. 5  is a perspective illustration of torsional vibration damping disk  32  before the insertion of the bow spring and before the deformation of the lug, of which only one lug is provided with reference numeral  34 . Furthermore, the receiving spaces for the bow springs inside deflected edge  36  are jointly marked with reference numeral  55  in  FIG. 5 . Receiving space  55  is divided by deformed areas  47  and  48  into several receiving spaces for the individual bow springs. 
   In  FIG. 6 , bow springs  31 ,  42  to  44  are inserted into the respective receiving spaces, which are delimited radially outwards by deflected edge  36  of torsional vibration damping disk  32 . However, the receiving spaces comprise an opening, of which the width is slightly larger than the outer diameter of the bow springs. This facilitates the insertion of the bow springs into the receiving spaces. However, there is the risk of the bow springs falling out of the receiving spaces when torsional vibration damping disk  32  comes to a standstill. In order to prevent this, the bow springs are preferably clamped with a slight pretension between the respective limit stops areas. Alternatively or additionally, the lugs, of which only lug  34  is provided with a reference numeral in  FIG. 6 , are bent out of torsional vibration damping disk  32  upwards from the plane of paper. 
   Lugs  34  are illustrated in the bent-out state in  FIG. 7 . As is apparent, the radially outer edge of lugs  34  rests radially inwards against the bow springs and fixes the latter in the receiving spaces. This reliably prevents the bow springs from falling out of the receiving spaces. 
     FIG. 8  is a perspective illustration of torsional vibration damping disk  62 , which resembles torsional vibration damping disk  32  illustrated in  FIGS. 2 to 7 . Like reference numerals are used for marking like parts. With a view to avoiding repetition, reference should be made to the preceding description of  FIGS. 2 to 8 . In the following, only the differences between the example embodiments are taken into consideration. 
   In torsional vibration damping disk  62  illustrated in  FIG. 8 , bow springs  31 ,  42  to  44  are prevented radially inwards from falling out by elevations, which are pressed out of torsional vibration damping disk  62 . Only one elevation  64  is provided with a reference in  FIG. 8 . Elevation  64  serves for the same purpose as the lug ( 34  in  FIG. 7 ) in torsional vibration damping disk  32 . 
   LIST OF REFERENCE NUMERALS 
   
       
         1  Torque converter 
         2  Rotation axis 
         3  Internal combustion engine 
         4  Housing 
         5  Housing wall close to the drive 
         6  Housing wall far from the drive 
         7  Gear 
         8  Hub part 
         10  Pump wheel 
         11  Turbine wheel 
         12  Turbine wheel hub 
         13  Guide wheel 
         14  Guide wheel hub 
         15  Freewheel 
         16  Converter lockup clutch 
         18  Piston 
         19  Collar on turbine wheel 
         20  Sealing 
         22  Friction surface 
         24  Friction surface 
         25  Intermediate plate 
         27  Intermediate plate 
         29  Torsional vibration damper 
         30  Receiving space 
         31  Energy storage element 
         32  Torsional vibration damping disk 
         33  Riveted joint 
         34  Lug 
         36  Deflected edge 
         42  Energy storage element 
         43  Energy storage element 
         44  Energy storage element 
         45  Limit stop 
         46  Limit stop 
         47  Deformed area 
         48  Deformed area 
         50  Flange 
         51  Through hole 
         52  Through hole 
         55  Receiving area 
         62  Torsional vibration damping disk 
         64  Elevation