Abstract:
A torque transmitting unit in the power train of a motor vehicle for transmitting torque between a drive unit having an output shaft and a transmission having at least one input shaft. At least one clutch unit is positioned between the drive unit and the transmission, and at least one vibration damping unit having an input part and an output part is provided and is connected between the drive unit output shaft and the clutch unit. The clutch unit includes a clutch cover that defines a clutch-containing volume and that is supported by a transmission housing section. The vibration damping unit is positioned with in the clutch-containing volume defined by the clutch cover. For optimization of structural space, both the input part and the output part of the vibration damping unit are supported in the radial direction by the clutch cover.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a torque transmitting unit in the power train of a motor vehicle for transferring torque between a drive unit, in particular a combustion engine, having an output shaft, in particular a crankshaft, and a transmission having at least one input shaft, in particular two input shafts, with at least one clutch device and at least one vibration damping unit having an input part and an output part, which is connected between the output shaft of the drive unit and the clutch device, the clutch unit having a clutch housing section, in particular a clutch cover, which limits the volume accommodating the clutch device and is supported by a transmission housing section, the vibration damping unit being positioned in the volume limited by the clutch housing section, which accommodates the clutch device.  
         [0002]     The object of the invention is to create a torque transmission device described above, optimized with regard to the construction space, which is simply constructed and is capable of being manufactured economically.  
       SUMMARY OF THE INVENTION  
       [0003]     The problem is solved in a torque transmitting unit in the power train of a motor vehicle for transferring torque between a drive unit, in particular a combustion engine, having an output shaft, in particular a crankshaft, and a transmission having at least one input shaft, in particular two input shafts, with at least one clutch device and at least one vibration damping unit having an input part and an output part, which is connected between the output shaft of the drive unit and the clutch device, the clutch unit having a clutch housing section, in particular a clutch cover, which limits the volume accommodating the clutch device and is supported by a transmission housing section, the vibration damping unit being positioned in the volume limited by the clutch housing section, which accommodates the clutch device, in that both the input part and the output part of the vibration damping unit or the input part of the clutch device are borne or supported in the radial direction directly or indirectly on the clutch housing section. The vibration damping unit is preferably a damped flywheel. Due to the support of the device according to the invention, bearing devices between the input part and/or the output part of the vibration damping unit and the transmission input shaft or the output shaft of the combustion engine may be dispensed with. In addition, the tolerance chain from the output shaft of the combustion engine to the transmission input shaft is reduced.  
         [0004]     The problem stated above is also solved in a torque transmitting unit described above by having the vibration damping unit positioned radially outside of the clutch device and overlapping it in the axial direction. That makes it possible to save construction space in the axial direction.  
         [0005]     The problem stated above is also solved in a torque transmitting unit described above by having the input part of the vibration damping unit comprise a vibration damping unit cage in which spring devices are at least partially contained, which are engaged by the output part of the vibration damping unit. An essentially circular-ring-shaped connecting piece, which extends out of the vibration damping unit cage, is preferably positioned between the clutch housing section and the clutch device, viewed in the axial direction.  
         [0006]     A preferred exemplary embodiment of the torque transmitting unit is characterized in that the input part of the vibration damping unit is welded to a hub part which is supported in the radial direction on the clutch housing section. The hub part can also be formed in a single piece with the input part of the vibration damping unit.  
         [0007]     Another preferred exemplary embodiment of the torque transmitting unit is characterized in that the hub part includes a hub bearing part which is of conical design on the inside and is provided with internal toothing that engages the external toothing which is formed on a coupling part that has a section which is formed complementarily to the cone of the hub bearing part. A separable attachment of the coupling part to the hub part is made possible through the conical, toothed sections which are engaged with each other.  
         [0008]     Another preferred exemplary embodiment of the torque transmitting unit is characterized in that the coupling part is attached to the hub bearing part so that it can repeatedly be separated non-destructively, in particular with the help of a screw connection. However, the coupling part can also be formed in a single piece with the hub part or welded to it.  
         [0009]     Another preferred exemplary embodiment of the torque transmitting unit is characterized in that the output part of the vibration damping unit is supported on the hub part, in particular in both the axial and the radial directions. For this purpose an essentially circular-ring-shaped indentation may be provided on the hub part, having a rectangular cross section which engages an essentially complementarily shaped elevation which is formed on the output part.  
         [0010]     Another preferred exemplary embodiment of the torque transmitting unit is characterized in that the clutch device includes a wet-operating clutch arrangement, in particular a multiple-disk clutch arrangement. Preferably, the clutch device includes two wet-operating multiple-disk clutch arrangements.  
         [0011]     Another preferred exemplary embodiment of the torque transmitting unit is characterized in that two wet-operating clutch arrangements are positioned coaxially and overlapping each other in the axial direction. That makes it possible to save construction space in the axial direction.  
         [0012]     In a power train of a motor vehicle, the problem indicated above is solved by installing a torque transmitting unit described above. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Additional advantages, characteristics, and details of the present invention are evident from the following description, in which various embodiments are described in detail with reference to the drawing. The characteristics mentioned in the claims and in the description may be essential to the invention individually by themselves or in any combination. The figures show the following:  
         [0014]      FIG. 1  shows a half-sectional view of a torque transmitting unit according to the present invention, in accordance with a first exemplary embodiment;  
         [0015]      FIG. 2  shows an enlarged cutout of a longitudinal section of a torque transmitting unit according to the present invention in accordance with another exemplary embodiment; and  
         [0016]      FIG. 3  shows a half-sectional view of a torque transmitting unit according to the present invention, in accordance with another exemplary embodiment. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Part of a power train  1  of a motor vehicle is illustrated in  FIG. 1 . Positioned between a drive unit  3 , in particular a combustion engine, and a transmission  5 , is a wet-operating double clutch  6  of multiple-disk design. Connected between drive unit  3  and double clutch  6  is a vibration damping unit  8 . The vibration damping unit is preferably a two-mass flywheel.  
         [0018]     An output shaft (not shown) of drive unit  3  is coupled with a drive output part  10 . Drive output part  10  has essentially the form of a circular ring extending in the radial direction, to which a starter gear rim  11  is welded radially on the outside. Drive output part  10  is connected through a screw connection  12  (of a plurality of screw connections which are evenly distributed around the circumference of drive output part  10 ) in a rotationally fixed connection to a connecting piece  14 . Welded radially on the inside of connecting part  14  is a hub part  15 , to which in turn an input part  17  of vibration damping unit  8  is welded. Positioned radially outside of hub part  15  and in the axial direction between connecting part  14  and input part  17  of vibration damping unit  8  is a clutch cover  20 , which extends essentially in the radial direction. Clutch cover  20 , with a seal  21  interposed, is supported on a transmission housing section  24 , which is shown with broken lines in  FIG. 1 . Transmission section  24  and clutch cover  20 , supported on it, are rigidly attached to the support structure of a motor vehicle.  
         [0019]     Clutch cover  20  has radially on its inside an essentially round cylindrical jacket-like bearing body  25 . Positioned on the side facing drive unit  3 , between bearing body  25  of clutch cover  20  and hub part  15 , is a sealing device  26 , in particular a radial shaft seal ring. Positioned on the side facing transmission  5 , between bearing body  25  of clutch cover  20  and hub part  15 , is a radial bearing device  28 , in particular a deep-groove ball bearing. Radial bearing device  28  is supported in the axial direction, toward drive unit  3 , on a shoulder  27 , which runs radially around the inside approximately in the middle of bearing body  25  of clutch cover  20 . Hub part  15  is supported on clutch cover  20  by means of radial bearing device  28 . Because of the support on shoulder  27  of bearing body  25  of clutch cover  20 , support in the axial direction toward drive unit  3  is also made possible.  
         [0020]     An additional mass  29  is attached radially on the outside of input part  17  of vibration damping unit  8 . The attachment of additional mass  29  to input part  17  of vibration damping unit  8  is preferably accomplished by a welded joint, as indicated in  FIG. 1 . In addition, attached to input part  17  of vibration damping unit  8  is a vibration damping cage  30 , which incorporates a plurality of spring devices  32  which extend in the circumferential direction. An output part  34  of vibration damping unit  8 , which is shown in  FIG. 1  with broken lines, engages spring devices  32 . Output part  34  is attached to a connecting part  36 , which forms the input part of the clutch. Output part  34  of vibration damping unit  8  may also be made in a single piece with clutch input part  36 . Clutch input part  36  transitions internally into a bearing cup  38 , which is supported in both the radial and axial directions and toward drive unit  3  in a complementarily formed bearing recess  40 , which is provided on the side of hub part  15  that faces transmission  5 .  
         [0021]     Clutch input part  36  is joined in one piece to an outer disk carrier  41  of a first multiple-disk clutch arrangement  42 . Positioned radially inside outer disk carrier is an inner disk carrier  44 , which is attached to a hub part  46 . Hub part  46  of first multiple-disk clutch arrangement  42  is connected in a rotationally-fixed connection to a first transmission input shaft  47 .  
         [0022]     Clutch input part  36  is connected in a rotationally fixed connection through a connecting part  50 , to which an additional mass  51  is attached radially on the outside, to an outer disk carrier  52  of a second multiple-disk clutch arrangement  54 , which is positioned radially inside of first multiple-disk clutch arrangement  42 . The two multiple-disk clutch arrangements  42  and  54  completely overlap each other in the axial direction. The second multiple-disk clutch arrangement  54  has an inner disk carrier  56  which is attached to a hub part  58 . Hub part  58  is connected in a rotationally fixed connection to a second transmission input shaft  59 , which is designed as a hollow shaft. The first transmission input shaft  47  is positioned in hollow shaft  59  so that it can rotate.  
         [0023]     The two multiple-shaft clutch arrangements  54  and  42  are operated by means of operating levers  61  and  62 , whose radially inner ends are supported on operating bearings  65 ,  66 . Operating bearings  65  and  66  are operated in the axial direction with the help of operating pistons  67 ,  68 . Operating pistons  67  and  68  are arranged in fixed positions with respect to operating levers  61  and  62 , which pivot with clutch input part  36 .  
         [0024]      FIG. 2  shows a longitudinal sectional view of a cutout of a clutch cover  80 , which is connected radially on the inside in a single piece to a bearing body  81 . Clutch cover  80  is positioned between two connecting pieces  82  and  85  which are attached to each other by a welded seam radially on the inside, in reference to clutch cover  80 . Welded seam  86  is located radially on the inside, partially under a bearing device  88 , which, viewed in the radial direction, is positioned between bearing body  81  of clutch cover  80  and the axially extending attaching sections of connecting parts  82  and  85 . Bearing device  88  is a deep-groove ball bearing, which is supported in the axial direction both on clutch cover  80  and on connecting parts  82  and  85 . Deep-groove ball bearing  88  is supported radially outwardly in the axial direction on a shoulder  89 , which is provided radially inwardly on bearing body  81 . On the opposite side, deep-groove ball bearing is supported radially outwardly on a supporting ring  91 , which is fixed in the axial direction on bearing body  81 , being partially accommodated in a groove which runs radially inside in bearing body  81 . Radially inwardly, deep-groove ball bearing  88  is supported in an axial direction on a fixing element  92  of hardened material. Fixing element  92  in turn is supported in the axial direction on connecting part  82 . In the opposite radial direction, deep-groove ball bearing  88  is supported radially inwardly on connecting part  85 . In addition, between bearing body  81  of clutch cover  80  and the attaching section of connecting part  82 , which extends in the radial direction, is a radial shaft seal ring  90 .  
         [0025]     Radially inside connecting parts  82  and  85 , a transmission shaft  94  is rotatably mounted with the help of a radial bearing device  96 . Between connecting part  82  and radial bearing device  96  is a sleeve  98  of hardened material. Sleeve  98  is connected in a single piece to a closing wall  99 , which is positioned at the end of transmission input shaft  94 , which is internally hollow, at a small distance from it. The open end of transmission input shaft  94  is closed by a cover  101 , through which the lubricants can pass from the interior of transmission input shaft  94  to reach bearing device  96 .  
         [0026]     Transmission input shaft  94  is connected through toothing  103  in a rotationally fixed connection to an output part  105  of a clutch device or vibration damping unit. An axial bearing device  108  is positioned in the axial direction between output part  105  and connecting part  85 . A retaining ring  110 , which is positioned partially in a groove in transmission input shaft  94 , fixes transmission input shaft  94  in an axial position relative to output part  105 . Connecting part  82  is connected in a rotationally fixed connection to an output shaft (not shown) of a drive unit, in particular a combustion engine. Connecting part  85  is the input part of a vibration damping unit.  
         [0027]      FIG. 3  shows an exemplary embodiment of a torque transmitting unit according to the present invention, similar to that in  FIG. 1 . The same reference labels are used to designate the same or similar parts. To avoid repetitions, we refer to the preceding description of  FIG. 1 . In the following description we will only go into the differences between the two embodiments.  
         [0028]     In the exemplary embodiment shown in  FIG. 3 , hub part  15  is not formed in one piece but in two parts. Hub part  15  includes a hub bearing part  121  which is releasably attachable, i.e., repeatedly non-destructively separable, in a rotationally fixed attachment to a hub bearing part  121 . Hub bearing part  121  has a cone-shaped section  125 , which tapers down in the direction of the transmission. Furthermore, cone-shaped section  125  has inner teeth. Coupling part  24  has a cone-shaped section  126  which is complementary in design to cone-shaped section  125  of hub bearing part  121 . Cone-shaped section  126  of coupling part  124  is provided with external toothing which engages the internal toothing of hub bearing part  121 . The cone-shaped form guarantees attachment of coupling part  124  to hub bearing part  121  without any play.  
         [0029]     Coupling part  124  is fixed on hub bearing part  121  in the axial direction with the help of a threaded bolt  128 . At the end of threaded bolt  128  facing the transmission there is a shoulder  130 , with which the threaded bolt  128  is supported on the end of hub bearing part  121  facing the transmission. A threaded sleeve  132  having outside threading is threaded into complementary inside threading of coupling part  124  in the radial direction between threaded bolt  128  and coupling part  124 . The end of threaded sleeve  132  which faces the transmission is supported on a hub bearing part  121 . On its end facing away from the transmission, threaded sleeve  132  has a collar  134 , with a nut  136  contacting its side which faces away from the transmission, which nut is screwed onto the end of threaded bolt  128  which points away from the transmission. At the end of threaded bolt  128  that points toward the transmission there is a radial bearing  140 , through which an inner transmission input shaft  142  is supported indirectly on hub bearing part  121 . Inner transmission input shaft  142  is positioned rotatably in a hollow outer transmission input shaft  144 .