Abstract:
A clutch unit ( 1 ) including at least one wet clutch ( 28, 29 ) and a torsional vibration damper ( 12 ) which are accommodated in a housing ( 8 ) driven by the drive unit. In order to simplify assembly, pre-assembled modular units ( 3, 4, 5 ) are formed that are joined together during the final assembly process. Advantageously, a separation point is provided between two modular units in the torsional vibration damper, wherein one modular unit ( 3 ) includes the energy accumulators ( 11 ) captively accommodated in a housing part ( 6 ), while the other modular unit ( 4 ) includes the output part of the torsional vibration damper as an input part ( 13 ) of the at least one wet clutch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/DE2009/001806, filed Dec. 22, 2009, which claims the benefit of German Patent Application No. 10 2009 005 076.0, filed Jan. 19, 2009, both of which are incorporated herein by reference as if fully set forth. 
     BACKGROUND 
     The invention relates to a clutch unit comprising at least one wet clutch and one torsional vibration damper that are accommodated in a housing driven by a drive unit. 
     Such clutch units have become known, for example, from DE 10 2005 030 192 A1. Here, a torsional vibration damper is arranged within the housing of a friction clutch with wet operation. Here, a housing part is equipped with the individual components and then connected, for example, welded tightly, to a second housing part, for example. Especially for clutch units with two wet clutches arranged one above the other in the radial direction and forming a double clutch, the number of components to be used increases, so that these can be accommodated in one housing part only with great effort. Especially during series production, long cycle times are required in the final assembly for this purpose. 
     SUMMARY 
     Therefore, the objective is to provide a clutch unit that is assembled from individual, pre-assembled components during the final assembly. 
     This objective is met by a clutch unit for a drive train with a drive unit and a subsequently arranged transmission with at least one wet clutch arranged in a housing that is driven by the drive unit and is formed from two housing parts connected at the outer periphery during the mounting of the clutch unit and a torsional vibration damper arranged between the housing and an input part of the at least one wet clutch with energy storage devices that are distributed across the periphery and charged, on one side, in the peripheral direction by the housing and, on the other side, by the input part, wherein the energy storage devices are captively accommodated in one of the housing parts before the joining of the housing parts and the at least one wet clutch is mounted before the joining of the housing parts. In this way, essentially three components are produced including the housing part facing the drive unit with the energy storage devices, the at least one wet clutch, and the housing part facing the transmission. The arrangement is here advantageously separated on the torsional vibration damper that could be constructed as a two-mass flywheel, wherein the two housing parts form the primary flywheel mass and the at least one wet clutch forms the second flywheel mass. Accordingly, the input part of the torsional vibration damper is the housing itself, while the output part of the torsional vibration damper is simultaneously the input part of the at least one wet clutch. The torsional vibration damper could have a one-stage or multiple-stage construction, wherein, for a relative rotation of the housing and at least one wet clutch relative to each other, the energy storage devices that are active in the peripheral direction are each acted upon by catches provided on the housing and on the input part and thus damp torsional vibrations. The energy storage devices are preferably constructed as bow springs extending across a wide angle of the periphery of the housing, wherein preferably two bow spring groups can be provided distributed across the periphery, with each of these groups being able to be formed from two bow springs nested one inside the other in the radial direction. Furthermore, a torsional vibration absorber, for example, a centrifugal force pendulum, could be connected in parallel to the torsional vibration damper, wherein its flyweights could be provided adjacent in the axial direction and at a similar height of the energy storage devices in the radial direction. 
     The captive accommodation of the energy storage devices can be realized through axial placement of these devices on a housing wall of the housing part facing the drive unit, wherein the energy storage devices are fixed in the axial direction by a ring washer part spaced apart in the axial direction from the housing wall and connected on the outside in the radial direction to the housing. The ring washer part could be placed on a radial projection after the placement of the energy storage devices in the housing part, wherein an anti-wear lining could be provided in the radial direction between the housing and the energy storage device and then can be fixed on the projection from the outside, in that, for example, the ring washer part and housing are welded with each other. The ring washer part here supports the energy storage devices against axial deflection during the operation of the torsional vibration damper. To this end, for example, in a construction of the energy storage devices as bow springs, for keeping the structural space on the inside free in the radial direction, a radial extension of the ring washer part up to half the winding diameter of the bow springs is sufficient. The ring washer part could be mapped at least partially to the periphery of the windings in the region of a contact face with the bow springs. 
     For the construction of the housing-side catches for the energy storage devices, stamped sections that apply a force on the end faces of the energy storage devices, such as bow springs, in the peripheral direction could be provided in the housing. Alternatively or additionally, the ring washer part could have catches that are exposed on the same periphery and are turned over essentially in the axial direction relative to the axis of rotation and thus engage in the axial direction between two ends of the energy storage device and apply a force on these in the peripheral direction. 
     The output-side catches of the torsional vibration damper are provided on the input part of the at least one wet clutch, wherein this has a flange part with catches extending outward in the radial direction for the energy storage device. These output-side catches are aligned, in operation, with the input-side, that is, housing-side catches. In order to achieve a corresponding orientation of the catches relative to each other in the peripheral direction during the mounting, corresponding positioning aids could be provided between the housing and the at least one wet clutch, wherein these positioning aids can alternatively or additionally be used as a centering aid until the clutch unit is accommodated on one or two transmission input shafts of the transmission. 
     The flange part with its arms constructed as catches extended in the radial direction advantageously has, on the outer periphery, a smaller diameter than the inner periphery of the ring washer part. In this way, the two components could be placed one inside the other in a simple way, because the flange part and ring washer part can engage one above the other in the axial direction during the assembly. In other embodiments it can be provided that the catches have a greater outer diameter than the inner diameter of the ring washer part, wherein the catches turned over in the axial direction of the ring washer part have a larger diameter than the outer diameter of the catches of the flange part. If the catches of the flange part enclose a smaller circular segment than the catches of the ring washer part, the ring washer part and flange part can likewise be brought past each other in the axial direction during assembly. Advantageously, the radial circular segments of the catches are approximately equal under consideration of production tolerances, so that passage is still just possible, without putting up with a noticeable rotational play without charging the energy storage devices. It is understood that for the construction of special embodiments, such a rotational play could be provided in that the circular segment-shaped extension of the catches of the flange part could be less than that of the catches of the ring washer part, especially when, in this angular region, a second damper stage should be effective. Furthermore, between the housing and the at least one wet clutch, a friction mechanism could be arranged that could be provided, for example, by the positioning or centering aids. 
     According to the inventive concept, the clutch unit can contain a double clutch with two wet clutches arranged one above the other in the radial direction, wherein torque is transmitted to both wet clutches via the input part. The two wet clutches are each acted upon separately by a hydraulic piston and have a hub that meshes with one of two transmission input shafts of the transmission. The pistons for activating the wet clutches, as well as the input part on which the torsional vibration absorber could also be accommodated, can be supported on a central clutch hub. The output parts of the clutches here form washer parts that could be arranged relative to each other in the axial direction and spaced apart in the axial direction from the housing wall running in the radial direction of the drive-side housing part. The spacing of the parts rotating with different rotational speeds is realized advantageously by axial bearings, for example, needle bearings. If such a clutch unit is equipped with only one wet clutch, then the configuration reduces to a hub with a washer part spaced apart in the axial direction from the housing wall. 
     The accommodation of the at least one wet clutch is realized on the clutch hub, wherein this is supported in a floating manner in the axial direction between the two housing parts or between a housing part and the transmission housing against the effect of energy storage devices active in the axial direction. To this end, at least one of the energy storage devices active in the axial direction could be a thrust washer. To this end, it has proven advantageous when the energy storage devices active in the axial direction or the thrust washers are produced as shim washers, corrugated rings, or disks corrugated across the periphery. These could be prevented from rotating in that these are fixed in the peripheral direction, for example, by external or internal teeth on an adjacent component and therefore rapid wear can be prevented. 
     One advantageous embodiment of a clutch unit with two wet clutches provides that the clutch hub is supported in the axial direction by an end face relative to a hub of an output part, such as a washer part of a first wet clutch that is supported so that it can rotate in the axial direction on a second hub of an output part, such as a washer part of a second wet clutch, wherein this is supported, in turn, on the housing part, such as the housing wall, facing the drive side. 
     Advantageously, the cooling of the at least one wet clutch can be performed by a cooling circuit, wherein pressurized medium is fed into the housing from the inside in the radial direction, for example, via the clutch hub, guided over the friction coating of the at least one wet clutch, and discharged again by a stationary suction pipe. It has proven especially advantageous to use the suction pipe accommodated rigidly on the transmission housing as an axial thrust point for the clutch hub. To this end, a thrust washer that is elastic in the axial direction could be provided between the suction pipe and the clutch hub and/or between the suction pipe and the transmission housing. 
     One advantageous embodiment provides a first component including a drive-side housing part and energy storage devices accommodated captively therein of the torsional vibration damper, a second component including two wet clutches that are arranged one above the other in the radial direction and are accommodated on a clutch hub and a third component connected on the outside in the radial direction to the first component after a centered accommodation of the second component in the first component with the transmission-side housing part. Here, on the third component on an axial projection provided on the inner periphery of the transmission-side housing, a drive for a pump could be provided and adjacent to this drive in the axial direction, a support for the clutch unit could be provided on a transmission housing. Alternatively, the drive for the pump could be pre-assembled using a rolling bearing on the transmission housing, wherein, during the mounting of the clutch unit on the transmission, a positive fit is formed between the housing, for example, the axial projection, and the pump drive in the peripheral direction, so that the housing drives the pump drive independent of the operating state of the at least one wet clutch. Here, the housing could be centered on the pump drive, so that this is likewise supported on the transmission housing so that it can rotate. Furthermore, the suction pipe could be accommodated with its fixation and pressurized medium passage lines on the third component. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in detail with reference to the embodiments shown in  FIGS. 1 and 2 . Shown herein are: 
         FIG. 1  is a schematic diagram of the components of a clutch unit in partial section; and 
         FIG. 2  is a partial section view through the clutch unit of  FIG. 1  in the assembled state. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows the clutch unit  1  arranged about the axis of rotation  2  in the state before the final assembly, wherein only the outlines of the three components  3 ,  4 ,  5  are shown. The two components  3 ,  5  here contain the housing parts  6 ,  7  that form the housing  8  of the clutch unit  1  and are connected tightly to each other, such as, for example, welded on the outside in the radial direction on the peripheries  9 ,  10  that overlap in the axial direction after the final assembly. The component  3  contains the energy storage devices  11  of the torsional vibration damper  12  and is connected locked in rotation with the not-shown drive unit, for example, of an internal combustion engine, such as a diesel or Otto engine. For the captive arrangement of the energy storage devices  11  and for preventing deflection during operation, these are fixed in the axial direction between the housing wall  15  and the ring flange part  16 . The input-side catches  17 ,  18  are here exposed by stamped sections in the housing wall  15  or from the ring flange part  16 . The output-side catches  19  of the input part  13  of the wet clutches arranged on the component  4 , wherein this input part is simultaneously used as the output part for the torsional vibration damper  12  and applies a force in the radial direction on the energy storage devices  11  via the catches  19  are bounded in the radial direction so that, while maintaining an assembly play, the catches  19  can be brought past when inserting the component  4  on the ring flange part  16 . To this end, the inner diameter of the ring flange part  16  is likewise bounded inwardly in the radial direction to half the diameter of the windings of the energy storage devices  11 , so that both the input-side and also the output-side catches obtain a sufficient overlap with the end faces of the energy storage devices  11 . 
     The component contains the housing part  7  and also the suction pipe  14  that is coupled in a fixed manner with the not-shown transmission housing after the joining of the components  3 ,  4 ,  5 . 
       FIG. 2  shows the clutch unit  1  in the assembled state as a partial section above the axis of rotation  2 . The clutch unit  1  is arranged between the drive unit, wherein only the crankshaft  20  of this drive unit is shown, and the transmission, wherein only the transmission housing  22  of this transmission is shown. The housing  8  of the clutch unit  1  is accommodated on the crankshaft  20  by a drive plate  21 , such as a flexplate that is flexible in the axial direction and compensates axial vibrations and wobble vibrations of the crankshaft  20  and is driven thereby. 
     Furthermore, the housing  8  is supported on the transmission housing  22  so that it can rotate by the roller bearing  23 , wherein the crown gear  25  for the transmission oil pump that can also circulate the pressurized medium of the clutch unit  1  is arranged between the ring-shaped axial projection  24  of the housing part  7  and the roller bearing  23  and is driven by the projection  24 . The pump drive formed from the crown gear  25  and the roller bearing  23  that also forms, above the crown gear  25 , a support for the housing  8  on the housing wall of the transmission housing  22  is pre-assembled advantageously on the transmission housing  22 , wherein, for the connection of the clutch unit  1  and transmission, the suction pipe  14  is centered in the feed mechanism and the guide pins  83  pass through this mechanism and are displaced in the axial direction in the transmission housing  22  and the suction pipe  14  is supported locked in rotation. Sealing washer  26  that is centered on the axial projection  24  and is made, for example, from sheet metal or plastic is provided with a seal  27 , such as a radial shaft sealing ring for the projection  24 , for sealing the housing  8  relative to the transmission housing  22 . 
     Within the housing  8  filled at least partially with pressurized medium, the torsional vibration damper  12  and the two wet clutches  28 ,  29  arranged one above the other in the radial direction are accommodated. The input part of the torsional vibration damper  12  is here formed by the housing that applies a force in the peripheral direction on the energy storage devices  11  that are active in the peripheral direction and are formed, in the shown embodiment, from advantageously two bow-spring groups arranged across the periphery each with two bow springs  30 ,  31  nested one inside the other in the radial direction, by the catches  17 ,  18  engaging in the radial direction in the ends of the bow springs  30 ,  31 . The catches  17  are here formed from deformations of the housing part  6  arranged across the periphery and the catches  18  are formed by exposed regions of the annular flange part  16 . The annular flange part  16  is placed on the radial projection  32  of the housing part  6  after placement of the bow springs  30 ,  31  and fixed in the axial direction, for example, welded, and are used for the captive accommodation of the bow springs  30 ,  31  before assembly and the axial guidance of the bow springs  30 ,  31  during operation. Between the bow springs  30  and the outer region of the housing part  6  in the radial direction, an anti-wear lining  33  is provided, which is arranged in two parts in the peripheral direction between the catches  17  and can be supported floating relative to the housing  8 . 
     The torsional vibration damper  12  is active in the torque flow path before the wet clutches  28 ,  29 , so that the output part of the torsional vibration damper  12  is simultaneously the joint input part  13  of the wet clutches  28 ,  29 . To this end, the input part  13  provides a flange part  13   a  with the output-side catches  19  of the torsional vibration damper  12 , which are constructed as arms extended in the radial direction of the flange part  13   a  and apply a force on the end faces of the bow springs  30 ,  31  in the non-tensioned state of the bow springs  30 ,  31  on the same periphery of the catches  17 ,  18  and thus cause a tensioning of the bow springs  30 ,  31  for a relative rotation of the housing  8  relative to the input part  13  of the wet clutches  28 ,  29 , so that the torque spikes causing such relative rotations are damped, in that the bow springs active as energy storage devices  11  temporarily buffer the energy of these torque spikes. 
     Through the use of the torsional vibration damper  12 , the torque of the drive unit is registered in the input part  13 . The input part  13  distributes the torque onto the input-side plate carriers  34 ,  35  of the wet clutches  28 ,  29  that are centered and supported by a common carrier disk  36  that is connected rigidly, such as welded, to the clutch hub  37 . A centrifugal force pendulum  51  with flyweights  52  that can be displaced to a limited extent relative to the carrier disk  36  in the peripheral direction and radial direction is arranged on the carrier disk  36  of the torsional vibration absorber  50 , for example—as shown—outside in the radial direction and advantageously spaced apart in the axial direction and at the same height in the radial direction. In the input-side plate carriers  34 ,  35 , plates  38 ,  39  are suspended that alternate in the axial direction with output-side friction plates  40 ,  41  and form a friction fit when an axial force is applied. The output-side friction plates  40 ,  41  are suspended in plate carriers  42 ,  43  that are each connected, such as, welded, to a hub  44 ,  45  with teeth  46 ,  47  to engage with the transmission input shaft  48  or with the transmission input shaft  49  arranged around this shaft and constructed as a hollow shaft, and are therefore supported and centered on the two transmission input shafts  48 ,  49 . 
     In the uninstalled state of the clutch unit  1 , the two wet clutches  28 ,  29  are equipped with the clutch hub  37  as component  4  ( FIG. 1 ). After installation, the clutch hub  37  is supported floating in the axial direction by the roller bearings  53 ,  54  on the transmission input shaft  49 . The transmission input shaft  49  is supported in the axial direction by the roller bearing  55  and fixed in the radial direction in the transmission housing  22 . 
     The floating support of the clutch hub  37  is limited by the two thrust washers  56 ,  57 . The thrust washer  56  is formed in one part from plastic and contains the carrier part  58  introduced into the end side of the clutch hub  37  and the lubricating oil grooves  59 . The hub  45  is applied in the axial direction and so that it can rotate relative to the hub  44  by the roller bearing  60 . The hub  44  is supported by the roller bearing  61  fixed in the axial direction so that it can rotate on the housing part  6 , so that the clutch hub  37  is supported in the axial direction by the shim washer  67 , in that, for example, a defined play is set by these parts. The axial biasing necessary for the bearings  60 ,  61  is set by the energy storage device  45   a  active in the axial direction, for example, a corrugated spring that is itself supported on the transmission input shaft  49  by the locking washer  45   b . In the opposite direction, the clutch hub  37  is supported by the sealing plate  62  that is arranged fixed on the projection  63  in the axial direction by the locking ring  64 , on the suction pipe  14  that is, in turn, supported in the axial direction by the thrust washer  65  that could be constructed as a roller bearing on the housing part  7 . Between the sealing plate  62  and the suction pipe  14 , the thrust washer  57  is arranged that is active in the axial direction and makes possible a displacement that is limited in the axial direction of the clutch hub  37  against its effect in the direction of the housing part  7 , so that the clutch hub  37  can be displaced to a limited extent in both axial directions, can be displaced relative to the housing  8 , and is therefore supported in a floating manner. The thrust washer  57  is formed from a carrier disk  66  meshed with the sealing plate  62  and a shim washer  67  that is accommodated rigidly on this carrier disk and comes in contact with a thrust washer  68  meshed with the suction pipe  14 . 
     The two wet clutches  28 ,  29  are charged by pistons  69 ,  70  that can be displaced in the axial direction by pressurized medium to press the plates  38  and  39 , respectively, in the axial direction with the friction plates  40  and  41 , respectively, against an end plate  71 ,  72  and therefore form a friction fit. To this end, the pressurized medium is led via rotating bushings  73 ,  74  into supply lines  75 ,  76  and dosed into the pressure chambers  77 ,  78 , wherein the pistons  69 ,  70  are displaced against the effect of the energy storage devices  79 ,  80  active in the axial direction and the wet clutches  28 ,  29  are each therefore closed according to the applied pressure of the pressurized medium. If the pressure in the pressure chambers  77 ,  78  dissipates, the wet clutches are automatically opened again by the release of tension by the energy storage devices  79 ,  80 . The supply lines  81 ,  82  are used for cooling the wet clutches  28 ,  29 , in particular, the friction linings of the friction plates  40 ,  41  that are exposed to particular heat stress especially under slipping conditions of the wet clutches  28 ,  29 . The pressurized medium dosed in this way cools the friction plates  40 ,  41  and flows outward in the radial direction, from where it is siphoned by the suction pipe  14  connected rigidly to the transmission housing  22  by the guide pins  83  and is fed to the transmission pan via the discharge line  84 . 
     A friction mechanism  85  can be provided between the torsional vibration damper  12  and the input part  13  of the wet clutches  28 ,  29 . To this end, a friction ring  87  that is centered by the retaining ring  88  mounted on the housing part  6  and is biased relative to this by the energy storage device  89  that is active in the axial direction and can be, for example, as shown, a plate spring, can be charged by pins  86  of the plate carrier  34 , wherein these pins are raised in the axial direction and are distributed across the periphery. Additionally or alternatively, the friction mechanism  85  could be used as a centering mechanism of the two wet clutches  28 ,  29  in the housing  8  before the final assembly as long as this is not yet centered on the transmission input shaft  49 . 
     LIST OF REFERENCE SYMBOLS 
     
         
         
           
               1  Clutch unit 
               2  Axis of rotation 
               3  Component 
               4  Component 
               5  Component 
               6  Housing part 
               7  Housing part 
               8  Housing 
               9  Periphery 
               10  Periphery 
               11  Energy storage device 
               12  Torsional vibration damper 
               13  Input part 
               13   a  Flange part 
               14  Suction pipe 
               15  Housing wall 
               16  Ring flange part 
               17  Catch 
               18  Catch 
               19  Catch 
               20  Crankshaft 
               21  Drive plate 
               22  Transmission housing 
               23  Roller bearing 
               24  Axial projection 
               25  Crown gear 
               26  Sealing washer 
               27  Seal 
               28  Wet clutch 
               29  Wet clutch 
               30  Bow spring 
               31  Bow spring 
               32  Projection 
               33  Anti-wear lining 
               34  Plate carrier 
               35  Plate carrier 
               36  Carrier disk 
               37  Clutch hub 
               38  Plate 
               39  Plate 
               40  Friction plate 
               41  Friction plate 
               42  Plate carrier 
               43  Plate carrier 
               44  Hub 
               45  Hub 
               45   a  Energy storage device 
               45   b  Locking washer 
               46  Teeth 
               47  Teeth 
               48  Transmission input shaft 
               49  Transmission input shaft 
               50  Torsional vibration absorber 
               51  Centrifugal force pendulum 
               52  Flyweight 
               53  Roller bearing 
               54  Roller bearing 
               55  Roller bearing 
               56  Thrust washer 
               57  Thrust washer 
               58  Carrier part 
               59  Lubricating oil groove 
               60  Roller bearing 
               61  Roller bearing 
               62  Sealing plate 
               63  Projection 
               64  Locking ring 
               65  Thrust washer 
               66  Carrier part 
               67  Shim washer 
               68  Thrust washer 
               69  Piston 
               70  Piston 
               71  End plate 
               72  End plate 
               73  Rotating bushing 
               74  Rotating bushing 
               75  Supply line 
               76  Supply line 
               77  Compression chamber 
               78  Compression chamber 
               79  Energy storage device 
               80  Energy storage device 
               81  Supply line 
               82  Supply line 
               83  Guide pin 
               84  Discharge line 
               85  Friction mechanism 
               86  Pin 
               87  Friction ring 
               88  Retaining ring 
               89  Energy storage device