Abstract:
The invention relates to a method for measuring the uniformity of the moments of shiftable friction clutch systems, the individual friction clutch system comprising an adapter at the input end and at least one adapter at the output end, as well as a system for measuring the uniformity of the moments of shiftable friction clutch systems. According to the invention, the friction clutch system is inserted into a measuring apparatus encompassing at least one moment measuring device. The clutch plates that transmit the driving power in a frictionally engaged manner are pressed against each other by means of a test force. The driving motor is driven at a certain test speed. The torque of the driving motor transmitted by means of the friction clutch system is measured within a certain interval with the aid of the moment measuring device. The inventive test method and measuring apparatus developed for a friction clutch system allow the friction clutch system to be measured and tested before the same is mounted on a transmission.

Description:
This application is a National Stage of International Application No. PCT/EP2006/012332, filed Dec. 20, 2006. This application claims priority to German Patent Application No. 10 2006 060 922.0, filed on Dec. 20, 2006 and German Patent Application No. 10 2005 062 413.8, filed on Dec. 23, 2005. The disclosures of the above applications are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a method for measuring the torque uniformity of shiftable friction clutch systems, with the individual friction clutch system having a drive-input-side adapter and at least one drive-output-side adapter, and to a measuring system for measuring the torque uniformity of shiftable friction clutch systems. 
     BACKGROUND OF THE INVENTION 
     DE 199 34 486 A1 discloses a method for testing an automatic transmission including its shift elements. For this purpose, the entire transmission with the mounted clutches and the brakes are placed onto a test bed and driven with a low level of power. The drive output is simulated with a torque measuring hub. 
     It is the object of the present invention to develop a measuring method and a measuring system for a friction clutch system by means of which the friction clutch system can be measured and tested before it is mounted in a transmission. 
     The above noted object is achieved by means of the features of the main claim. According to the claim, the friction clutch system is inserted into a measuring device, with the measuring device holding the drive-input-side adaptor by means of a first holding device and engaging around a drive-output-side adapter by means of a further holding device. One of the holding devices is connected to a drive motor. The measuring device comprises at least one torque measuring device. The clutch plates, which transmit the drive force in a frictionally engaging manner, are pressed against one another by means of a preload device which generates a test force. The drive motor is driven at a test rotational speed. Within a time interval, the torque of the drive motor which is transmitted by means of the friction clutch system is measured by means of the torque measuring device. 
     The measuring system for measuring the torque uniformity comprises at least one measuring device. The individual measuring device comprises at least two holding devices. One of the holding devices of the respective measuring device is connected to a drive motor. Furthermore, the individual measuring device comprises a torque measuring device and a preload device for the opposite loading of the two holding devices. 
     Further details of the invention can be gathered from the subclaims and from the following description of schematically illustrated embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial sectional view of a dual-shaft clutch in a preferred embodiment of the present invention; 
         FIG. 2  is a schematic view of a manually-actuated clutch measuring machine in a preferred embodiment of the present invention; 
         FIG. 3  is a top plan view of an automated measuring system in a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates, as an example of a shiftable clutch system  300 , a dual-shaft clutch  300  of a motor vehicle. The dual-shaft clutch comprises two liquid-lubricated friction clutches  50 ,  150 . The force-fitting shift clutches have two friction packs  55 ,  155  arranged radially in series. Accordingly, the first friction pack  55  is situated on a larger radius than the second friction pack  155 . The two clutches  50 ,  150  are closed hydraulically. The release of the individual clutches  50 ,  150  takes place by means of spring elements and/or hydraulically by means of corresponding cylinder-piston units. The spring elements  100 ,  200  are for example mechanical springs such as coil springs and/or diaphragm springs. The clutch  300  is generally used in passenger vehicles. 
     The clutch  300  is positioned for example between a multi-shaft shift transmission and the drive motor of the vehicle. The drive motor is generally a spark-ignition or diesel engine. A single- or dual-mass flywheel  3  is often mounted between the drive motor and the clutch system. 
     The torque passes from the crankshaft to the flywheel  3 , (See  FIG. 1 ). The latter is seated by means of a rotationally rigid shaft-hub connection  21  on the clutch input shaft  20 . Downstream of the shaft-hub connection  21 , the clutch input shaft  20  widens so as to form a driver disk seat  22 . The driver disk  30  is fastened to the driver disk seat  22 . 
     The driver disk  30  which is for example deep-drawn is rotationally rigidly connected to an outer plate carrier  40 . The latter has two annular plate carrying sections  58  and  158 . The outer plate carrier  40 , which is a sheet metal part produced for example in a punching and deep-drawing process, is fastened to a main hub  47 . The combination of the clutch input shaft  20 , driver disk  30 , outer plate carrier  40  and main hub  47  rotates at the motor rotational speed. The parts  20 ,  30 ,  40 ,  47  are situated—in the exemplary embodiment—in permanent engagement with the crankshaft of the drive motor. 
     The clutch input shaft  20  has a central bore  24  in which a first transmission input shaft  51  is mounted by means of rolling bearings. A first plate carrier flange  53  is arranged on the transmission input shaft  51  by means of a shaft-hub connection  52 . A first pot-shaped plate carrier  54  is welded to the plate carrier flange  53 . The plates  56 ,  57  of the first clutch  50  are arranged between the first plate carrier  54  and the outer plate carrying section  58  of the outer plate carrier  40 . Here, the outer plates  56  engage in a form-fitting manner into the profiling of the outer plate carrying section  58 . The outer plates  56  are mounted in a rotationally rigid yet longitudinally displaceable manner on the plate carrying section  58 . The inner plates  57  which are seated between the outer plates  56  are connected in a similar way to the profiling of the first inner plate carrier  54 . 
     The outer plate carrier  40  forms, together with the main hub  47 , an annular cylinder  45 . As per  FIG. 1 , a cylinder outer wall  48 , which is substantially U-shaped in partial cross section, is rigidly arranged on the main hub  47  so as to be offset laterally to the left with respect to the annular cylinder  45 . A first annular piston  61  which is formed from a deep-drawn metal sheet is arranged between the cylinder outer wall  48  and the annular cylinder  45 . The annular piston  61  has a piston section  62  and a force transmission section  67 . A first working space  80  is situated between the piston section  62  and the cylinder outer wall  48 . 
     The working space  80  is acted on with pressurized oil in order to press the force transmission section  67  against the first plate pack  55 . For this purpose, the force transmission section  67  engages by means of tongues  70  into the interior space  46  of the outer plate carrier  40 . When the first clutch  50  is actuated, the tongues  70  press the plate pack  55  against a stop  59  which is fixed in the outer plate carrier  40 . In the engaged state, the clutch input shaft  20  is connected by means of the outer plate carrier  40  and the first inner plate carrier  54  to the first transmission input shaft  51 . One of the gearwheels which is arranged on the shaft  51  then meshes in a force-transmitting manner with a gearwheel on the transmission output shaft. The gearwheels and the transmission output shaft are not illustrated in  FIG. 1 . 
     A diaphragm spring  100  is positioned between the force transmission section  67  and the outer plate carrier  40  as a restoring element. The diaphragm spring  100  releases the force transmission section  67  from the first plate pack  55  when the first working space  80  is relieved of pressure. 
     A second transmission input shaft  151  is mounted, for example by means of two needle-roller bearings, in the main hub  47 . The transmission input shaft  151 , which is embodied as a hollow shaft, surrounds the first transmission shaft  51  at least in regions. Situated at the front shaft end—which is aligned toward the clutch input shaft  20 —is a shaft-hub connection  152 , by means of which a second plate carrier flange  153  is rotationally rigidly arranged on the second transmission input shaft  151 . The inner plate carrier  154  of the second clutch  150  is fastened to the plate carrier flange  153 . 
     Arranged between the second inner plate carrier  154  and the first inner plate carrier  54  is a second inner plate carrying section  158 . The inner plate carrying section is welded to the outer plate carrier  40 . The second inner plate carrier  154  and the outer plate carrier  40  fix the second plate pack  155  in a known way. 
     Arranged within the installation space of the second inner plate carrier  154  is a compensating space delimiting wall  191 , which is fastened to the main hub  47 . The delimiting wall  191  has the shape of an annular duct which surrounds the second compensating space  190  on three sides. 
     Arranged between the compensating space  190  and the outer plate carrier  40  is a second annular piston  161 . The annular piston  161  which is divided into a piston section  162  and an actuating section  167  presses—during engagement—with the actuating section  167  against the second plate pack  155 . 
     The piston section  162  closes off a second working space  180  which is formed by the outer plate carrier  40  and a cylinder ring  181 . The second working space  180  is in this case sealed off with respect to the two components  40 ,  181  by means of lip seal rings. The piston section  62  of the first annular piston  61  has similar seals. The cylinder ring  181  is likewise fastened to the main hub  47 . The annular piston  161  is also sealed off with respect to the compensating space  190 . 
     If the second clutch  150  is actuated, as the first clutch  50  opens, the outer plate carrier  40  is connected to the second inner plate carrier  154 . The motor torque is thereby transmitted to the second transmission input shaft  151 . Corresponding gearwheels transmit the rotational movement, with an altered torque, to the transmission output shaft (not illustrated) which drives the drivetrain. 
     A plurality of spring elements  200 , for example in the form of coil pressure springs, are arranged in the second compensating space  190 . The spring elements  200  are supported between the second annular piston  161  and the delimiting wall  191 . The annular piston  161  is raised from the corresponding friction pack  155 , inter alia by means of the spring elements  200 , as the second clutch  150  is released. 
     The individual components of the dual-shaft clutch  300  are initially produced separately and are subsequently assembled. The assembly takes place for example at individual, separate workstations or along a production line with a plurality of stations and automated workpiece transportation. Here, for example, proceeding from a basic assembly, individual components are automatically or semi-automatically mounted, and if appropriate secured, at the different stations. 
     Even if all the individual parts are produced within the permissible tolerances, deviations can result from the sum of the production and assembly tolerances, which deviations influence the operating properties of the friction clutch system  300 . 
     For example, if the concentricity of the outer plate carriers  40 ,  140  differs from one another, the pressure piston seals are loaded non-uniformly. This can bring about a non-uniform movement for example of the piston  61  and thereby cause a non-uniform plate pressing force. 
     The plates  56 ,  57 ;  156 ,  157  of the friction packs  55 ,  155  can have unevennesses. This can lead to a variation of the pressing force, and therefore to a fluctuation of the torque which can be transmitted by means of the dual-shaft clutch  300 , during a revolution of the dual-shaft clutch  300 . 
     A further influential factor can be a non-circularity of the groove for the stop ring  59 . This can cause non-uniform contact of the plate pack  55 . 
     Such deviations which are listed by way of example can, individually or in combination, influence the operating properties of the friction clutch  300 . The deviations result for example in a non-uniformity of the torque transmitted by means of the friction clutch system  300  for example from the crankshaft via the clutch input shaft  20  to the respective transmission input shaft  51 ;  151 . Here, the amplitudes and the period length of the fluctuation of the torque over a revolution or over a time interval are measures of the torque uniformity. 
     In order to measure the torque uniformity, the assembled friction clutch system  300  is tested and measured by means of a measuring system  400 . For this purpose, the friction clutch system  300  is inserted into a measuring device  420  of a measuring machine  410 . The measuring machine  410  of this type is illustrated in  FIG. 2 . The measuring machine  410  comprises for example a frame  411  having a machine pedestal  412  and a workpiece carriage  414  which is displaceable on a guide  413 . 
     The machine pedestal  412  can be fixedly or detachably connected to the frame  411 . A machine pedestal  412  which is movable on the frame  411  is also conceivable. In this exemplary embodiment, the machine pedestal  412  supports a drive motor  441  and for example a transmission  442  (not illustrated in any more detail here) with a fixed transmission ratio. The output shaft  443  of the transmission  442  supports a holding device  421 . 
     The guide  413  is in this exemplary embodiment a longitudinal guide, for example in the design of a flat guide. The guide direction  419  is aligned parallel to the longitudinal edge of the frame  411  and to the shaft of the drive motor  441 . 
     The workpiece carriage  414  can be moved along the guide  413  manually or by means of a drive. The position of the workpiece carriage  414  on the guide  413  can be secured for example by means of a clamping device. The workpiece carriage  414  supports a second holding device  431  which is aligned here with the first-mentioned holding device  421 . The holding device  431  is in this exemplary embodiment connected by means of a plurality of hydraulic lines  435 , of which only one is illustrated in  FIG. 2 , to the frame  411 . Also arranged on the workpiece carriage  414 , which in this case forms a rigid longitudinal stop  418 , is for example a torque measuring device which is not illustrated in  FIG. 2 . The torque measuring device comprises for example a load cell. In order to transmit the torque of the clutch  300 , the holding device  431  is for example connected by means of a rotary leadthrough to a lever which acts on the load cell. 
     In the illustration of  FIG. 2 , a clutch system  300  is inserted into the measuring device  420 . Here, for example the clutch input shaft  20 , which in this case forms a drive-input-side adapter  301  of the clutch system  300 , is seated in the carriage-side holding device  431 . The hydraulic connections of the clutch system  300  are for example hydraulically connected to the lines  435 . 
     The transmission input shafts  51 ;  151 , the drive-output-side adapter  311  of the clutch system  300 , are seated in the pedestal-side holding device  421 . The clutch system  300  can of course also be inserted into the measuring device  420  in such a way that the transmission input shafts  51 ;  151  are seated in the carriage-side holding device  431  and the clutch input shafts  20  are arranged in the pedestal-side holding device  421 . 
     In order to insert the clutch system  300  into the measuring device  420 , the workpiece carriage  414  is for example moved to the left in the illustration of  FIG. 2 . The clutch system  300  is now inserted into the measuring device  420  by hand, by means of a handling device etc., in such a way that for example the clutch axis  5  is aligned with the axes of the holding devices  421 ,  431 . The workpiece carriage  414  is subsequently moved to the right in the illustration of  FIG. 2  and is secured for example by applying the clamping device. Here, for example, the hydraulic connections are made between the clutch system  300  and the holding adapter  431 . The spray guard  450  is subsequently closed. 
     In order to measure the torque uniformity, a lubricating oil flow with for example 3 liters per minute is for example firstly activated. Here, the friction faces  56 ,  57 ;  156 ,  157  of the clutch system  300  are wetted. The clutch system  300  is subsequently closed by means of the hydraulics of the measuring device  420 . The closing function can also take place pneumatically. Here, for example, the friction faces  55 ,  56  of the first friction clutch  50  of the clutch system  300  are firstly pressed against one another by means of a preload device which generates a constant force at least during the measurement. The force is for example is set such that the torque which can be transmitted between the friction faces  55 ,  56  of the friction clutch  50  is between 10 and 100 Newton meters. The torque, in one example, is set to 30 Newton meters for the measurement. The torque which can be transmitted is calculated from the product of the pressing force, the number of friction faces, the mean friction radius and the friction coefficient. 
     The drive motor  441  is now activated, such that for example the output shaft  443  of the transmission  442  of the drive motor  441 —and therefore the first holding device  421 —has a rotational speed of from 1 to 1000 revolutions per minute. The rotational speed is constant during the measurement. 
     The torque which is applied to the friction clutch  50  can be determined by means of a load cell, measuring flange or measuring shaft. 
     The measurement by means of the described measuring system  400  is carried out in this exemplary embodiment during a time interval of for example 90 seconds. Here, the force profile—and on account of the lever arm of constant length, also the torque profile—over time are measured in a computer-aided manner. The measurement results in a torque profile with maxima and minima. The torque profile can be periodic. 
     The repetition frequency of the maxima and minima can be determined from the torque profile for example by means of a Fourier analysis. Here, the first-order maxima are for example the maxima with the highest amplitude, and the higher-order maxima are for example maxima of lower amplitude. The Fourier analysis takes place for example in a computed-aided manner during the measuring interval. Instead of a complete Fourier analysis, it is possible, for example in order to reduce the data quantity to be processed, to carry out a so-called fast Fourier transformation. 
     The amplitude of the torque signal over the frequency—the result of the Fourier analysis—is for example a classification feature of the measured friction clutch  50 . The lower the amplitudes are, the more uniform the torque profile is. A friction clutch  50  with low amplitudes is classified for example as a very good clutch  50 , a clutch  50  with high amplitudes is classified for example as a poor clutch  50 . 
     The workpiece carriage  414  can also comprise a brake motor which has for example an output rotational speed of from 0.01 rev/min to 1 rev/min. The torque difference between the drive input torque and drive output torque is then for example determined during the measurement of torque uniformity. The measurement can take place at the drive input side or drive output side. 
     By means of the method, it is also possible to determine the torque uniformity of the second friction clutch  150  of the dual-shaft clutch  300 . 
     After the measurements, the hydraulic supply lines are for example shut off and the residual oil is centrifuged out at high rotational speed. 
     The removal of the measured clutch system  300  from the measuring device  420  takes place in the reverse sequence to the insertion. Depending on its classification, the clutch system  300  can be supplied to the further flow of material. 
     The measuring device  420  can advantageously be incorporated into an automated production line. The clutch system  300  which is fully assembled at individual stations of a production line of the type is conveyed by means of a workpiece supply device  600  into a test region  650  for torque uniformity. 
       FIG. 3  shows a plan view of a test region  650  with a measuring system  400  which has two measuring machines  410 ,  510  with in each case one measuring device  420 ,  520 . The main components of the measuring machines  410 ,  510  and of the measuring devices  420 ,  520  are at least of similar construction to the components of the measuring machine  410  and the measuring device  420  illustrated in  FIG. 2 . 
     In the illustration of  FIG. 3 , the workpiece supply device  600  conveys the clutch systems  300  on workpiece carriers  605 ,  606  from bottom to top. In order to convey the workpiece carriers  605 ,  606  into the test region, the spray guard  625  is initially opened. The workpiece carriages  414  of the measuring machines  410 ,  510  are in a rear rest position. The workpiece carrier  605 , with a clutch system  300 , which is situated in front in the conveying direction  609  is conveyed into the working space  525  of the measuring device  520  which is situated downstream in the conveying direction  609 . The workpiece carrier  606  which is situated behind in the conveying direction  609  is conveyed into the working space  425  of the measuring device  420 . 
     Once the workpiece carriers  605 ,  606  have reached the positions, the workpiece carriers  605 ,  606  are for example raised by means of a lifting device (not illustrated here). The position of the raised clutch  300  in the working space  425  is illustrated for example in the lower measuring device  420  of  FIG. 3 . Once the clutch axis  5  coincides with the central axes of the holding devices  421 ,  431 , the workpiece carriage  414  moves in the direction of the machine pedestal  412 . The clutch  300  is held by the two holding devices  421 ,  431 . The workpiece carrier  605 , which can if appropriate also be moved in the transverse direction with respect to the conveying direction  609 , can thereafter be lowered. A clutch system  300  which is inserted into the measuring device  520  is illustrated for example in the upper measuring device  520  of  FIG. 3 . As the clutch system  300  is inserted, the hydraulic connections are for example also made. 
     The measuring devices  420 ,  520  can also comprise brake motors. 
     The measurement and the evaluation of the torque uniformity takes place for example as described in connection with  FIG. 2 . The drag torque can also be determined as described by means of the automated measuring system  400 . 
     The two measuring devices  420 ,  520  described here can be connected to the same evaluating device. The evaluating device is in turn for example connected in a data-exchanging manner to a production central computer. 
     The removal of the clutches  300  from the measuring devices  420 ,  520  takes place in the reverse sequence to their insertion. Once the clutches  300  are resting on the workpiece carriers  505 ,  506 , the latter are conveyed out of the test region  650  in the conveying direction  609  after the spray guard  625  is opened. 
     Instead of the dual-shaft clutch  300  described here, it is also possible for a single shaft clutch to be measured and tested. 
     In a series production process, it is possible by means of the method according to the invention and the measuring system for all of the series-produced clutches to be measured for torque uniformity. The measured torque uniformity is then compared with a torque uniformity limit value and, in the event of the limit value being exceeded, the clutches are correspondingly overhauled, and thereafter re-measured, or else are removed from the series production process. As a particular advantage, it is ensured by means of the method that all the clutches which leave the series production line reliably adhere to predefined specifications with regard to torque uniformity (100% inspection). 
     LIST OF REFERENCE SYMBOLS 
     
         
         
           
               1  Dry space; transmission region; dry 
               2  Transmission wet space 
               3  Dual-mass flywheel, flywheel 
               5  Rotational axis of the clutch system 
               10  Transmission housing, housing bell 
               11  Partition 
               20  Clutch input shaft 
               21  Shaft-hub connection 
               22  Driver disk seat 
               24  Bore, central 
               30  Driver disk 
               39  Spacing between ( 55 ) and ( 41 ) 
               40  First outer plate carrier, clutch component 
               41  Inner wall of ( 40 ) 
               42  Outer wall of ( 40 ) 
               43  Bead, bead elevation 
               44  Central line 
               45  Annular cylinder 
               46  Interior space 
               47  Main hub 
               48  Cylinder outer wall 
               49  Recesses for ( 70 ) 
               50  First friction clutch, clutch 
               51  First transmission input shaft 
               52  Shaft-hub connection 
               53  First plate carrier flange 
               54  First inner plate carrier 
               55  Plate pack 
               56  Outer plates, clutch parts 
               57  Inner plates, clutch parts 
               58  Plate carrying section, outer 
               59  Stop, stop ring 
               60  First actuating element 
               61  First annular piston, piston, pressure piston 
               62  Piston section 
               67  Force transmission section 
               70  Tongues 
               71  Tongue end face 
               73  Tongue length 
               74  Central line 
               75  Gap 
               76  Gap base 
               79  Circle on which ( 44 ) and ( 74 ) lie 
               80  First working space 
               90  First compensating space 
               99  Rear space 
               100  Diaphragm spring, plate spring, restoring element 
               130  Recess reinforcement, clip 
               131  Tube section 
               132  Flange ring section 
               133  Latching hook 
               140  Casing, sleeve 
               144  Bore 
               145  Chamfer 
               146  Internal corner roundings 
               150  Second friction, clutch 
               151  Second transmission input shaft 
               152  Shaft-hub connection 
               153  Second plate carrier flange 
               154  Second inner plate carrier 
               155  Plate pack 
               156  Outer plates, clutch parts 
               157  Inner plates, clutch parts 
               158  Plate carrying section, inner 
               160  Second actuating element 
               161  Second annular piston, piston, compensating piston 
               162  Piston section 
               167  Actuating section 
               180  Second working space 
               181  Cylinder ring 
               190  Compensating space 
               191  Compensating space delimiting wall 
               200  Spring elements, restoring springs, coil springs 
               300  Friction clutch system, dual-shaft clutch 
               301  Drive-input-side adapter 
               311  Drive-output-side adapter 
               400  Measuring system 
               410  Measuring machine 
               411  Frame 
               412  Machine pedestal 
               413  Guide 
               414  Workpiece carriage 
               418  Longitudinal stop 
               419  Guide direction 
               420  Measuring device 
               421  Holding device 
               425  Working space 
               431  Holding device 
               435  Hydraulic lines 
               441  Drive motor 
               442  Transmission 
               443  Output shaft of ( 442 ) 
               450  Spray guard 
               510  Measuring machine 
               520  Measuring device 
               521  Holding device 
               525  Working space 
               531  Holding device 
               541  Drive motor 
               542  Transmission 
               600  Workpiece supply device 
               605  Workpiece carrier 
               606  Workpiece carrier 
               609  Conveying direction 
               625  Spray guard 
               650  Test region