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CROSS-REFERENCE TO A RELATED APPLICATION 
       [0001]    This application is a National Phase Patent Application of International Patent Application Number PCT/DE2006/000292, filed on Feb. 14, 2006, which claims priority of German Patent Application Number 10 2005 008 437.0, filed on Feb. 24, 2005. 
     
    
     BACKGROUND 
       [0002]    The invention relates to a window lifter. 
         [0003]    U.S. Pat. No. 5,806,244 shows a window lifter with two racks. The racks, which lie opposite each other, each interact with a pinion which mesh together. One of the pinions is coupled to a drive. The window pane is moved along the rack system by means of the motor. Under some circumstances, the pinion—rack system does not provide adequate precise guidance for a window pane. 
         [0004]    DE 43 40 013 A1 discloses a window lifter, in which a guide rail has a rack toothing which interacts with a pinion in a follower drive unit. The guide rail has a bend which extends in the direction of movement of the follower drive unit and interacts in a sliding manner with guide surfaces of the follower drive unit which surrounds the guide rail in the region of the bend. The pinion is guided in this manner in relation to the rack toothing—the follower drive unit together with the pane it carries likewise being guided in this way. The pane which is to be raised and lowered is attached directly to the drive motor on the upper side of the follower drive unit. 
         [0005]    DE 40 05 759 A1 discloses a window lifter, in which the follower drive unit is guided in relation to the guide rail, which has a toothing, via rolling bodies. 
       SUMMARY 
       [0006]    It is therefore the object of the present invention to further develop a window lifter of this type. 
         [0007]    The invention proposes a window lifter for a motor vehicle, comprising a guide rail with a rack toothing, along which a follower drive unit, which carries the pane, can be moved by means of a pinion which meshes with the rack toothing, and in which the follower drive unit is guided in relation to the guide rail via rolling bodies, wherein the follower drive unit has the following subassemblies:
       a drive motor,   a guide and gearing unit which holds the pinion and the at least one rolling body, and   a support which holds drive motor and the gearing unit.       
 
         [0011]    The invention firstly provides a spatially functional delimitation of the individual subassemblies and, secondly, the integration thereof to form a follower drive unit which can be variably and optimally matched to the conditions present. The drive motor is thus preferably coupled to the gearing unit via a coupling which connects the motor shaft of the motor to the shaft of the worm of the worm gearing for the pinion. Different motors can therefore be connected in a simple manner. The worm which interacts with a worm wheel is mounted via two bearing points, which are assigned to its end regions, in the gearing. The coupling which connects the motor shaft to the worm is preferably constructed as a claw coupling in the manner of an Oldham coupling. As a result, axial and radial tolerances are compensated for. 
         [0012]    According to one exemplary embodiment of the invention, it is provided that the worm and the worm wheel which interacts with the worm are accommodated in an encapsulated region of the guide and gearing unit. This region has permanent lubrication and is sealed in relation to the guide and gearing unit. 
         [0013]    It is preferable for the invention if the worm gearing is not of self-locking design, and the worm wheel is connected via a wrap spring brake to the pinion which meshes with the toothing of the guide rail. A torque which is exerted on the wrap spring by the pinion expands the wrap spring in relation to a brake cup—blocking the friction locking mechanism. A torque which is exerted by the worm wheel on the wrap spring neutralizes the locking effect of the latter—the torque can be transmitted to the pinion. 
         [0014]    The guide and gearing unit preferably has an electronic unit region which is arranged in the region of the coupling which connects the motor shaft to the worm. The electronic unit accommodated in the electronic unit region can have a Hall sensor and a ring magnet, which is fitted to the shaft of the worm, which detect the movement of the shaft. Signals for controlling the drive in terms of nip protection and the like can be derived therefrom. However, it is also possible in this electronic unit region for an electronic unit to be accommodated which, via a magnetic track on the guide rail, directly determines the absolute position of the follower drive unit and therefore of the pane to be raised and to be lowered. 
         [0015]    The drive motor and the guide and gearing unit coupled to the drive torque are preferably integrated directly in the support which holds said units. In this case, the pane to be raised and to be lowered is arranged above the support and is therefore located essentially above the motor shaft or in the plane of the worm wheel. This results in a favorable utilization of construction space—the distance between the front side of the follower drive unit and the rear side of the guide rail can therefore be designed to be relatively level. 
         [0016]    According to one exemplary embodiment of the invention, one section of the support which holds the drive motor and the guide and gearing unit is designed as half of the guide and gearing unit and here has the bearing points/supporting means for the rolling bodies, the pinion and the worm wheel driving the pinion. The receptacles for the bearings which carry the worm are likewise integrated in this region. Via a covering, the worm—worm wheel rolling region is separated off from the region in which rolling body and coupling are located. 
         [0017]    It is preferably provided that the guide surface which interacts with the rolling bodies is designed as a surface which runs perpendicularly with respect to the plane of the guide rail. In particular, two guide surfaces which run parallel to each other and each interact with at least one rolling body are provided. By this means, precise guidance of the pinion in relation to the rack toothing is possible. The rolling bodies can have a convexly, concavely or conically designed running surface which interacts with the guide surface. 
         [0018]    According to one exemplary embodiment of the invention, it is provided that the rolling body or the rolling bodies is or are each mounted about a rigid axis in relation to the follower drive unit. In order to compensate for tolerances, it can be provided in this case to keep rolling bodies with different diameters ready and to use precisely the rolling body, or the pairing of rolling bodies, in which play-free guidance of the follower drive unit arises. In a development, it can also be provided that the rolling body or the rolling bodies is or are mounted resiliently in relation to the follower drive unit. The rolling bodies are therefore adjusted in a play-free manner in relation to the guide rail. 
         [0019]    An exemplary embodiment in which the running surface of the rolling body has a softer/harder material than the material of the guide rail results in low-wearing running of the rollers and prevents much noise from being produced. A suitably selected pairing of material also guarantees that the rolling bodies will roll—a sliding of the rollers over the guide surface is prevented. 
         [0020]    An advantageous guidance of the pinion in relation to the rack toothing arises if at least one rolling body is arranged parallel to the plane of the pinion which meshes with the rack toothing, and the rolling body interacts with a guide surface which runs parallel to the rack toothing, and, in addition, the rolling body is coupled to the pinion which meshes with the rack toothing. The rolling guidance of the pinion results in a defined interaction of the teeth of rack and pinion. 
         [0021]    An exemplary embodiment of the invention provides that the follower drive unit can be equipped with pinions of different diameter and, correspondingly, with rolling bodies of corresponding diameter. The selection of the pinion diameter desired transmission ratios can therefore be realized. Since, in accordance with the diameter of the pinion, the follower drive unit is then also positioned differently with respect to the guide rail, the compensation takes place by the use of correspondingly large rolling bodies. Simple assembly which can be matched to different conditions can thus be provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Furthermore, an exemplary embodiment of the invention is explained with reference to the figures, in which: 
           [0023]      FIG. 1  shows the window lifter according to the invention with guide rail, the electronic unit region is closed by means of the cover. 
           [0024]      FIG. 2  shows the window lifter according to the invention with guide rail, the electronic unit region is removed with the cover. 
           [0025]      FIG. 3  shows the window lifter according to the invention with guide rail, the electronic unit region is removed with the cover. 
           [0026]      FIG. 4  shows the window lifter according to the invention with guide rail. 
           [0027]      FIG. 5  shows the window lifter according to the invention with guide rail. 
           [0028]      FIG. 6  shows the drive motor together with guide and gearing unit. 
           [0029]      FIG. 7  shows the mounting of the rolling bodies of the bearing plate of the guide and gearing unit. 
           [0030]      FIG. 8  shows the bearing plate of the guide and gearing unit, with pinion removed. 
           [0031]      FIG. 9  shows the bearing plate of the guide and gearing unit, with pinion removed. 
           [0032]      FIG. 10  shows the bearing plate of the guide and gearing unit, with pinion removed. 
           [0033]      FIG. 11  shows the pinion and the connection thereof to the worm wheel. 
           [0034]      FIG. 12  shows the pinion and the connection thereof to the worm wheel. 
           [0035]      FIG. 13  shows the pinion and the connection thereof to the worm wheel. 
           [0036]      FIG. 14  shows the pinion and the connection thereof to the worm wheel. 
           [0037]      FIG. 15  shows the window lifter and components according to the invention in an exploded illustration. 
           [0038]      FIG. 16  shows the window lifter and components according to the invention in an exploded illustration. 
           [0039]      FIG. 17  shows the window lifter and components according to the invention in an exploded illustration. 
           [0040]      FIG. 18  shows the window lifter and components according to the invention in an exploded illustration. 
           [0041]      FIG. 19  shows a rear view of a follower drive unit of the window lifter from  FIGS. 1 to 5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0042]      FIGS. 1-5  show a guide rail  1  which is preferably manufactured from plastic and along which a follower drive unit  2  can be moved. The guide rail  1  has a toothing  3  which interacts with a pinion  30  (not illustrated here) in a guide and gearing unit  4  of the follower drive unit  2 . Furthermore, two guide surfaces  5 ,  6  are integrally formed on the guide rail  1 , one of said guide surfaces  6  running parallel to the toothing  3 . In this case, the guide surface  6  lies precisely on the pitch circle of the pinion  30  which interacts with the toothing  3  ( FIGS. 11 ,  12 ). The lower end of the guide rail  1  is assigned an end stop  7  with an elastic element. 
         [0043]    Drive motor  8  and the guide and gearing unit  4  are held by a support  9  designed in the form of a molded part. The rotor housing of the drive motor  8  (pole cup) is embedded here in an opening  10 , which is designed in accordance with the external dimensions of said rotor housing, of the support  9 . That end of the drive motor  8  which holds the dome bearing of the motor shaft  18  is fixed on the support  9  via a latching receptacle  11 . The bearing plate  12 , which can be inserted into the support  9 , of the guide and gearing unit  4  has a receptacle for an electronic unit region  13  with a plug-in connection  13 . 1 , which region is closed by a cover  14  together with sealing via latching elements. Instead of a plug-in connection  13 . 1 , a ribbon cable or a ribbon conductor connected directly to the printed circuit board  15  can also be led out here.  FIG. 1  shows the electronic unit region  13  closed by means of the cover  14 ,  FIGS. 2 and 3  show the electronic unit region  13  with the cover  14  removed. A printed circuit board  15  with an electronic unit  16  is accommodated in said electronic unit region  13 , the upper printed circuit board  15  having been removed and thus only the components of the electronic unit  16  being illustrated in  FIG. 3 . By means of the electronic unit  16  accommodated in the electronic unit region  13 , the movement of the motor shaft  18  is detected via a ring magnet  17 , explained further below—furthermore, a second signal transmitter system interacts with a magnetic signal track  19  in order to detect the absolute position of the follower drive unit  2 . The cover  14  of the electronic unit region  13  has a peripheral seal which interacts with the inner wall of the receptacle of the electronic unit region  13  ( FIGS. 17 ,  18 ). 
         [0044]    The receptacle of the electronic unit region  13  is located on a bearing plate  12  of the guide and gearing unit  4 . Said bearing plate  12  can be removed from the support  9 , as illustrated in  FIGS. 4 ,  5  and  6 . The guide and gearing unit  4  of the support  9  holds three individual rolling bodies  20 ,  21 ,  22  which interact with the two guide surfaces  5 ,  6  of the guide rail  1 . The motor shaft  18  of the drive motor  8  is coupled to a worm  24 —the shaft  25  thereof—via a claw coupling  23  with an elastic intermediate layer. The elastic intermediate layer between the two claws of the coupling  23  secures motor shaft  18  and the shaft  25  of the worm  24  in place. Positional tolerances of the two shafts  18 ,  25  are therefore compensated for in a manner free from play. A ring magnet  17  is located on that part of the coupling  23  which is assigned to the shaft  25  and interacts with a signal transmitter of an electronic unit (not illustrated here). 
         [0045]    The two ends of the worm  24 —the shaft  25 —are held in the guide and gearing unit  4  (the bearing plate  12 ) in a manner supported rotatably and axially via a respective bearing  26 ,  27 . A worm wheel  28  meshes with the worm  24 , the worm  24 —worm wheel  28  system not being of self-locking design so as to obtain good efficiency. In order to absorb forces exerted on the follower drive unit  2  (for example the weight of the pane), the worm  24  interacts via a wrap spring  29  with the pinion  30 , which is illustrated in  FIG. 7 . The pinion  30  has parallel a rolling body surface  31  which interacts with the guide surface  6  running next to the toothing  3  ( FIGS. 1-5 ). The rolling body  20  also interacts with said guide surface  6  ( FIG. 7 ). 
         [0046]      FIG. 7  shows the mounting of the rolling bodies  20 ,  21 ,  22  on the bearing plate  12  of the guide and gearing unit  4 . The mounting takes place via integrally formed bearings  33 . The pinion  30  and the rolling body surface  31 , which is fitted and coupled parallel to the pinion  30 , are located on the side, which faces the guide rail  1 , of a sealing element  32 , which is manufactured from elastic material, of the bearing plate  12 . Below said sealing element  32 , the worm wheel  28  together with the shaft  25  of the worm  24 , which shaft is mounted at both ends in the bearings  26 ,  27 , is located in a filling of grease. Furthermore, the elastic sealing element  32  also fixes the bearings  26 ,  27  in a manner free from play in their correspondingly shaped receptacles of the bearing plate  12 , and brings about a noise reduction. 
         [0047]      FIG. 8  shows the bearing plate  12  of the guide and gearing unit  4 , with pinion  30  removed, and of the sealing element  32 . The pinion  30 , which is not illustrated in  FIGS. 8 ,  9  and  10 , together with rolling body surface  31  is mounted rotatably on a peg  43  of the bearing plate  12  of the guide and gearing unit  4 . In this case, said peg  43  reaches through an opening of the worm wheel  28 , into which the stem  34  of the pinion  30  is rotatably inserted ( FIGS. 11 and 12 ). On the end side, the pinion  30  has two claws  35  which dip into two recesses  36  of the worm wheel  28  in the manner of a claw coupling. One claw  35  of the pinion  30  interacts in a recess  36  of the worm wheel  28  with the bent ends of a wrap spring  38  which is seated on a collar  37  of the worm wheel  28  ( FIG. 13 ). Pinion  30 , the rolling body surface  31 , the collar  37  and the claws  35  form a unit which is preferably composed of a single piece. The wrap spring  38  interacts via its outer circumference with a metal strip ( FIG. 14 ) which forms the brake cup  39  and, for its part, is embedded in a correspondingly shaped receptacle of the bearing plate  12  of the guide and gearing unit  4  ( FIG. 10 ). The metal strip of the brake cup has a small thickness, and therefore it can fit precisely and snugly against the cylindrical receptacle in the bearing plate  12 . Wrap spring  38  and metal strip of the brake cup  39  thereby form the wrap spring brake  40  of the follower drive unit. 
         [0048]      FIGS. 15-18  show, in an exploded illustration, the follower drive unit  2  with and without guide rail  1 . The bearing plate  12  has a flange region  41  for holding the drive motor  8 .  FIG. 18  illustrates the components pinion  30 , wrap spring  38 , brake cup  39 , bearing plate  12  and the cover  14  of the electronic unit region  13 .  FIGS. 15 and 16  show that, on the side facing the guide rail  1 , the support  4  has a respective rear-acting rail grip  42  in the form of a region designed as a hook. The follower drive unit  2  is therefore fixed perpendicularly with respect to the plane of the guide rail  1 . In the rear view of the follower drive unit  2  according to  FIG. 19 , the rear-acting rail grips  42  are reproduced—the latter are located in the region of the recesses in the support for the rolling body  20  and the pinion  30  and lying opposite in the region of the drive motor  8 . The support  9 , the bearing cover  12 , the covering  32  of worm  24  and worm wheel  28  and the cover  14  of the electronic unit region are manufactured from plastic.

Summary:
A window lifter for a motor vehicle is provided. The window lifter comprising a guide rail with a rack toothing, along which a follower drive unit, which carries the pane, can be moved by means of a pinion which meshes with the rack toothing, and the follower drive unit is guided in relation to the guide rail via rolling bodies. The follower drive unit comprising a drive motor, a guide and gearing unit which holds the pinion and the at least one rolling body, and a support which holds drive motor and the guide and gearing unit.