Abstract:
A hydrodynamic torque converter ( 1 ), comprising a turbine wheel ( 9 ) driven by an impeller ( 8 ) and connected to an output part, and comprising a housing ( 34 ), in which a torsional vibration damper ( 19 ) having several damper stages ( 17, 20 ) and a centrifugal force pendulum ( 11 ), and also a converter lockup clutch ( 18 ) connecting a housing and an output part ( 3 ), are accommodated. In order to avoid any striking of the pendulum masses of the centrifugal force pendulum in internal combustion engines having large oscillating angles driving the torque converter, a turbine damper is connected in the power flow upstream of the centrifugal force pendulum.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is filed under 35 U.S.C. §120 and §365(c) as a continuation of International Patent Application No. PCT/DE2009/001342, filed on Sep. 24, 2009, which application claims priority from German Patent Application No. 10 2008 051 972.3, filed on Oct. 16, 2008, which applications are incorporated herein by reference in their entirety. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a hydrodynamic torque converter with an impeller, a turbine, a lock-up clutch as well as a torsional vibration damper and a torsional vibration absorber. 
       BACKGROUND OF THE INVENTION 
       [0003]    Torque converters are familiar in drive trains of motor vehicles and are preferably disposed between an internal combustion engine and a transmission. Thereby, the converter&#39;s function with excessive torque increase is preferably utilized for starting the motor vehicle, in that the torque from the housing that is driven by the internal combustion engine is transmitted via the impeller that in turn drives the turbine that transmits torque via an output part with the support on a stator for torque increase to a transmission input shaft of the transmission unit. At higher speeds, the lock-up clutch is closed so that torque is transmitted directly from the housing via the output part to the transmission input shaft, bypassing the converter components, and the deteriorating efficiency of converter components at higher speeds is inhibited. 
         [0004]    The internal combustion engines finding application, particularly 4-cylinder diesel engines, feature high rotational irregularities so that torsional vibration dampers are provided in the housing of the torque converter, which can be disposed effectively in the closed lock-up clutch between the housing and the output part and/or for an open lock-up clutch, between turbine and the output part of the torque converter. Thereby, a torsional vibration damper in the known manner is understood as an arrangement with an input- and an output part, which, for instance, contrary to the effect of energy accumulators disposed over the circumference, are limitedly rotatable relative to one another. Such torsional vibration dampers can contain several damper stages that are disposed in series and/or in parallel to one another. 
         [0005]    For improved vibration insulation of torsional vibrations of the internal combustion engine, the application of centrifugal force pendulums in the housing of the torque converter has been disclosed, which can also be integrated effectively in the housing in connection with torsional vibration dampers. Such an arrangement of damping units may not be adequate in internal combustion engines of the above-mentioned type, so that pendulum weights on the centrifugal force pendulum are possible. The design of the centrifugal force pendulum can therefore be difficult, particularly at low speeds with high swivel angles of the internal combustion engine. Limit stops of pendulum weights or masses act, particularly, on the drive train of a motor vehicle, through a humming sound that causes discomfort. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Object of the invention is a torque converter with corresponding vibration insulation, in which a centrifugal force pendulum is not exposed or only exposed in a reduced manner, to pendulum knocks, and/or the design of the centrifugal force pendulum is simplified under such conditions, for instance, the vibration angle of the centrifugal force pendulum is reduced. 
         [0007]    The object is met by a hydrodynamic torque converter with a turbine driven by an impeller and connected with a output part as well as housing, in which a torsional vibration damper with several damper stages and a torsional vibration absorber as well as housing and lock-up clutch connecting the output part are installed additionally. The torsional vibration absorber is connected with the turbine and is formed by a centrifugal force pendulum and a turbine absorber. By dividing the torsional vibration absorber into a turbine absorber and a centrifugal force pendulum, improvement of vibration insulation is achieved, in that by connecting the turbine absorber in the torque path upstream of the centrifugal force pendulum, the latter can be tuned to a smaller vibration angle in a less complex manner. Thus, for instance, vibration angles of the pendulum masses relative to the disk part carrying them can be made smaller than 40°, without them knocking on the disk part under normal operating conditions of a drive train, for instance, in connection with a 4-cylinder diesel engine. 
         [0008]    The torsional vibration insulation unit, consisting of a torsional vibration damper, which can comprise the clutch damper assigned to the lock-up clutch and a turbine damper assigned to the turbine, and a torsional vibration absorber can be designed such that individual components are equipped with multiple functions depending upon the operating state of the lock-up clutch. For instance, damper elements such as damper stages of the torsional vibration damper can be assigned to the torque path via converter components like impeller and turbine to the torque path via the lock-up clutch. Moreover, depending upon the manner of operation of the lock-up clutch, the turbine absorber can be designed as a pure absorber or as a vibration damper. For instance, the turbine absorber works as an absorber for a closed lock-up clutch, such that the turbine forms an absorber mass of the turbine absorber. For an open lock-up clutch, the turbine absorber forms a damper stage of a turbine damper acting between turbine and output part. 
         [0009]    Furthermore, a clutch damper assigned to the lock-up clutch can be formed as two-stage. In an advantageous manner, for a damper stage of the clutch damper for a closed lock-up clutch, the turbine damper can be switched in so that it is used together by both the clutch damper and the turbine damper. For this purpose, the clutch damper comprises an intermediate part common to both damper stages. This intermediate part can still be connected non-rotatably with a flange part of the turbine absorber. Thereby, to facilitate the function of a torsional vibration damper, the turbine absorber is equipped with a cover plate that is limitedly rotatable relative to the flange part against the effect of energy accumulators, which on the other hand is connected non-rotatably with the turbine. For an open lock-up clutch, the torque present on the housing from the internal combustion engine flows via the impeller to the turbine. The turbine absorber serves as the first damper stage and feeds torque via the cover plate and the energy accumulator to the intermediate part and from there via the second damper stage of the clutch damper into the output part of the torque converter, from where it is fed into the transmission input shaft. The centrifugal force pendulum is assigned non-rotatably to the turbine by means of a disk part and acts in this configuration state as a single torsional vibration absorber. 
         [0010]    In the closed state of the lock-up clutch, the torque from the housing is fed via the lock-up clutch into the first damper stage of the torsional vibration damper and from there into the output part of the transmission input shaft. Through the linkage of the turbine absorber to the intermediate part of both damper stages, the turbine absorber couples to the clutch damper by means of its flange parts, whereby the turbine connected to the cover plate serves as an absorber mass. Thereby, hydrodynamic effects, particularly the blades of the turbine contribute additional moments of inertia. The centrifugal force pendulum, for example, coupled with the turbine is thereby only exposed to the vibration angles—not yet absorbed—by the turbine absorber and can be dimensioned accordingly for a smaller vibration angle. 
         [0011]    An advantageous embodiment in this case provides for an output part of the torque converter, which is connected non-rotatably with a transmission input shaft of a transmission. On the output part, for instance, a so-called damper hub splined with the transmission input shaft, an input part of the clutch damper and a turbine hub is mounted rotatably and an output part of the torsional vibration damper is mounted non-rotatably. Thereby, the output part of the torsional vibration damper and the output part of the torque converter are formed advantageously, for instance, manufactured by means of a sintering- or forging process. In this embodiment, the turbine hub non-rotatably accommodates the cover plate, the turbine and the disk part of the centrifugal force pendulum carrying the pendulum mass on the turbine hub. On the turbine hub, a radially raised, revolving flange can be provided, on which cover plate, turbine hub and disk part are mounted, for example, by common riveting or other fastening means. 
         [0012]    In an advantageous manner, a friction device can be provided between the flange part and the cover plate, for instance, in the form of a diaphragm spring braced between the flange part and the cover plate. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0013]    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: 
           [0014]      FIG. 1  a schematic depiction of a prototype in a motor vehicle; 
           [0015]      FIG. 2  a diagram depicting the vibration insulation of different torsional vibration insulation units; and 
           [0016]      FIG. 3  a partial section through a hydrodynamic torque converter. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]      FIG. 1  shows a schematically depicted prototype of a drive train  100  in a motor vehicle with a hydrodynamic torque converter  1 , which is driven by an internal combustion engine  2 , for instance, a 4-cylinder diesel engine. Torque is transmitted by the engine and possibly converted via an output part  3  to a transmission input shaft  5  belonging to the transmission  4 . In the transmission  4 , which can be an automated manual transmission, an automated gearshift stages or a continuously variable transmission, like toroidal or chain CVT, the transmission ratios are set corresponding to the driving states of the vehicle and the driving torque transmitted via a differential unit  6  to at least a drive wheel  7 . 
         [0018]    The torque converter  1  serves as a starting- and torque transmission element and provides two torque paths for the transmission of torque loaded with torsional-vibration, provided by the internal combustion engine  2 . The one torque path is established through the hydrodynamic transmission via the impeller  8  and the turbine  9  coupled to it by means of a working fluid, whereby the turbine  9  is assigned symbolically to the turbine mass  10  on which the centrifugal force pendulum  11  is disposed. Energy accumulators  13  and a friction device  14  are disposed between the turbine mass  10  or rather the turbine  9  and an intermediate part  12 , which are active during rotation of the turbine  9  relative to the intermediate part  12 . Via the intermediate part  12 , the input part of the damper stage  17  with the energy accumulators  15  and the output part  16 , the torque from the output part  16  is transmitted to the output part  3  of the torque converter  1 . 
         [0019]    The second torque path occurs via the lock-up clutch  18  that is connected directly to or via a housing—not depicted—of the torque converter  1  upstream of the torsional vibration damper  19  with the two damper stages  17 ,  20 . In this case, torque flows from the input part  21  of the torsional vibration damper  19  via the energy accumulator  22  of the first damper stage, whose output part is formed by the intermediate part  12 , via the second damper stage  17  and the output part  3  in the transmission input shaft  5 . 
         [0020]    The operation of the torsional vibration insulation unit  23 , comprising the torsional vibration damper  19  and torsional vibration absorber  30 , for damping the torsional vibrations introduced from the internal combustion engine  2 , occurs in different ways depending upon the torque flow via both torque paths. For an open lock-up clutch  18 , the turbine absorber  24  is effective as a turbine damper stage  25  as a result of torque flowing through it. The turbine  9 , forms the input part and the intermediate part  12  forms the output part of this damper stage and the turbine damper stage  25  is connected upstream of the damper stage  17  by forming a two-stage turbine damper  26 . The centrifugal force pendulum  11  with its disk part  28  and the pendulum masses  29  that is limitedly displaceable relative to the latter in rotation direction is thereby assigned to the turbine  9  and acts as a single component of the torsional vibration absorber  30 . The damper stage  20  has no function in converter&#39;s operation. It is obvious that, in converter operation for torque increase, a stator—non-depicted—can be disposed between the impeller  8  and turbine  9 . 
         [0021]    For a closed lock-up clutch  18 , the two damper stages  17 ,  20 , disposed in series against one another, are effective as a clutch damper  31 , thus, the effect of the turbine damper stage  25  is dispensed with, since the turbine  9  is freely rotatable apart from a moment of inertia set through the turbine mass  10  and viscosity torque relative to the working fluid. The cover plate  31  is rotationally coupled with the intermediate part  12  in connection with the energy accumulators  13  coupled to the turbine mass  10  and the friction device  14  in the turbine absorber  24 , which forms a two-piece torsional vibration absorber  30  for a closed lock-up clutch  18  in connection with the centrifugal force pendulum  12  coupled to the turbine mass  10 . 
         [0022]      FIG. 2  shows a diagram that shows the curves  32 ,  33  sampled on the differential  6 , which respectively depict residual rotational irregularity AM plotted over the speed n of different torsional vibration insulation units disposed in a torque converter. The curve  32  with the symbols (o) shows the rotational irregularities of a drive train with a 4-cylinder diesel engine with a torque converter, in which a centrifugal force pendulum is effective without a switched-in turbine absorber. Through the wide vibration angles of this internal combustion engine in the speed range of approx. 1000/min, the pendulum masses of the centrifugal force pendulum knock on the disk part and cause noise on the differential, which is perceived as humming, and can be amplified by the body of the motor vehicle. Equipping the centrifugal force pendulum with vibration angles, which could prevent mutual knocking of the pendulum masses, does not meet the objective, for instance, due to reasons of tuning and manufacturing with correspondingly narrow tolerances, associated with a high technical scope. 
         [0023]    The curve  33  with the symbols (x) shows the arrangement of  FIG. 1 . Regardless of a small vibration angle of pendulum masses in the range smaller than 40°, no significantly outstanding peaks occur over the uniform shape of the curve  33 , which hint at a contact of the pendulum masses with the disk part. The turbine absorber  24  ( FIG. 1 ) is therefore in a position to filter out vibration angles with large amplitudes so that the centrifugal force pendulum can be designed to absorb smaller vibration angles. 
         [0024]      FIG. 3  shows an example embodiment of a torque converter  1  of  FIG. 1 . The torque converter  1  is mounted in the housing  34  driven by the internal combustion engine, to which the impeller  8 —as shown—is directly coupled or to which it is connectable by means of a separating clutch in other exemplary embodiments. The impeller  8  drives the turbine  9 ; a stator  35  is disposed between the impeller  8  and the turbine  9  by means of a one-way clutch  36  attached to a fixed—non-depicted—transmission housing stator support. 
         [0025]    The turbine  9  is fastened on the turbine hub  38 , for example, by means of rivets  37 . Also the disk part  28  of the centrifugal force pendulum  11  is fastened with the pendulum masses  29  by means of rivets  37 . The cover plates  31 , which are formed by the plates holding two of the energy accumulators  13 , riveted together radially outside, are fastened non-rotatably on the turbine hub  38 . The turbine absorber  24  is formed by the cover plates  31  connected with the turbine  9  and on the other hand pressurizing the energy accumulator  13  and the flange part  39  on the one hand pressurizing the energy accumulator  13  as well as the friction device  14  acting in between, through the diaphragm spring, formed between the cover plate  31  and the flange part  39 . 
         [0026]    The lock-up clutch  18  is formed in the depicted exemplary embodiment by a lamella package  40  that, for a closed lock-up clutch  18 , transmits the torque present on the housing  34  to the lamella carrier  41 , which is rigidly connected and riveted with the input part  21  of the torsional vibration damper  19 . The torsional vibration damper  19  is formed as a two-stage unit with the damper stages  17 ,  20 . The intermediate part  12  is disposed between the two damper stages  17 ,  20 , which respectively pressurize the energy accumulators  15 ,  22  respectively on the input and/or output side. The energy accumulators  15  of the damper stage  17  are pressurized on the output side by the output part  16  of the torsional vibration damper  19 , which is formed as a single piece with the output part  3 . The output part  3  is splined with the transmission input shaft—not depicted in this exemplary embodiment—and limitedly receives the turbine hub  38  in a rotatable manner. 
         [0027]    It is clear that, without change of the proposed concept, further advantageous space optimization measures on the torque converter  1  depicted in  FIG. 3  are taken. For instance, the energy accumulators  13  use the space of the axial drawn-in torus-shaped ring room of the turbine  9 , in the radial section above the riveting with the turbine hub  38 . Thus, the disk part  28  and the constituent parts of the turbine absorber  24  can be matched accordingly. 
         [0028]    The functional manner of the torque converter  1  of  FIG. 1  was explained in detail based on the principle sketch of  FIG. 1  and is at least essentially applicable to the torque converter  1  depicted in  FIG. 3  that only deviates, as an exemplary embodiment, from the design of the torque converter  1  from  FIG. 1 . 
       REFERENCE SYMBOLS LIST 
       [0000]    
       
           1  hydrodynamic torque converter 
           2  internal combustion engine 
           3  output part transmission 
           4  transmission 
           5  input shaft 
           6  differential unit 
           7  driving wheel 
           8  impeller 
           9  turbine 
           10  turbine mass 
           11  centrifugal force pendulum 
           12  intermediate part 
           13  energy accumulator 
           14  friction device 
           15  energy accumulator 
           16  output part 
           17  damper stage 
           18  lock-up clutch 
           19  torsional vibration damper 
           20  damper stage 
           21  input part 
           22  energy accumulator 
           23  torsional vibration insulation unit 
           24  turbine absorber 
           25  turbine damper stage 
           26  turbine damper 
           27  clutch damper 
           28  disk part 
           29  pendulum mass 
           30  torsional vibration absorber 
           31  cover plate 
           32  curve 
           33  curve 
           34  housing 
           35  stator 
           36  one-way clutch 
           37  rivet 
           38  turbine hub 
           39  flange part 
           40  lamella package 
           41  lamella carrier 
           100  drive train 
         AM non-uniformity of rotation 
         n speed