Abstract:
The arrangement has an axial securing element for fixing to the rotor shaft to enclose it at least over a tangential partial region, especially in the form of a spreader ring for fitting onto the rotor shaft, and a spring element pressing axially elastically against the stator part for axial play compensation as part of the securing element.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of co-pending International Application No. PCT/EP01/13198 filed Nov. 14, 2001 which designates the United States, and claims priority to European application number EP00125136.2 filed Nov. 17, 2000. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to an arrangement for axial slack compensation of a rotor shaft. 
     BACKGROUND OF THE INVENTION 
     From EP 0133 527 B2, an arrangement is known for limiting the axial slack of a rotor shaft, on a sliding bearing, of a motor drive relative to its housing part, whereby a shim washer, corresponding in each case to the measured axial slack, can be permanently fitted to the housing as an axial stop part. 
     Motor or motor gear arrangements with an elastic axial stop part in the form of an elastic element held at the housing end are known from FR-A-1 415 584 or FR-A-2 253 940. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide axial slack compensation combined with reduced component and production costs and guaranteed operating safety, particularly with respect to mass-produced variable drives for vehicles. 
     This object is achieved in accordance with the invention by an arrangement for axial slack compensation in accordance with the following features: an axial securing element attachable to the rotor shaft and enclosing its circumference at least over a tangential part area, particularly in the form of an expanding ring that can be fitted onto the rotor shaft; and an elastic element elastically pressable axially against the stator part in the sense of compensation for the axial slack, as part of the securing element. 
     The production parts and assembly stages are reduced by the integration of a securing element, normally already present as an axial position stop securing element, particularly an expansion ring pressed into a radial recess in a rotor shaft, with an elastic element particularly in the form of elastic element arms. 
     The production cost can be further reduced if the securing element and the elastic element are parts of a component pressed as a single piece from sheet metal. 
     By means of an intermediate disk, torsionally resistant to the securing and elastic element, provided between the securing and elastic elements on one side and the stator part on the other, with axial stop buffers on one of its front faces, and a sliding face to stop against the front face provided on the stator part on the other, both a defined elastic course during the elastic deformation of the elastic element can be achieved and also a high degree of operating safety with long operating service times due to low wear. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention and also advantageous embodiments of the invention explained in more detail in the drawing on the basis of exemplary embodiments. These are as follows: 
         FIG. 1  A perspective exploded view of the rotor of a commutator motor with axial slack compensation with respect to the stator part in accordance with the invention. 
         FIG. 2  An arrangement according to  FIG. 1  in the assembled-for-operation position. 
         FIG. 3  A perspective exploded view of a securing element with an integrated elastic element in accordance with the invention and an associated intermediate disk. 
         FIG. 4  An arrangement according to  FIG. 3  in the assembled-for-operation position. 
         FIG. 5  An arrangement according to  FIG. 4  showing a view in a different direction. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In a perspective exploded view,  FIG. 1  shows a rotor with a rotor shaft  5  provided with an arrangement for axial slack compensation with respect to a stator part  4  in accordance with the invention and mounted on it a still unwound rotor pack  6  and a commutator  7 . The rotor shaft  5  is mounted in a cap  3  that is adjustably held by a clamping collar  3 . 1  in the cap recess  3 . 2  of the stator part  4 . 
     For axial support of the rotor shaft  5  against the stator part  4 , a securing element  1  in the form of an expanding ring  1 . 1 ;  1 . 2  is used, that in this exemplary embodiment is axially located by engaging in a shaft recess in the form of an annular groove  5 . 1  and can also be tangentially located by clamping by means of radially attached expanding fingers  1 . 1  or  1 . 2 . 
     For elastic compensation of the axial slack between the rotor shaft  5  and stator part  4 , the securing element  1  according to the invention is formed as an elastic element  1 . 3 ;  1 . 4  and for this purpose has, for each expanding finger  1 . 1  or  1 . 2 , concentric outer elastic limbs  1 . 3  or  1 . 4  respectively, each of which is connected in an axially elastic manner by one free end of the limbs and by its other limb end, via a yoke  1 . 5  as a single piece, to the expanding fingers  1 . 2  or  1 . 3  at the ends facing away from the free ends of the limbs. 
     An intermediate disk  2 , moving relative to the rotor shaft  5  and rotated by the securing element  1 , is fitted axially between the support at the elastic elements  1 . 3 ;  1 . 4 , integrated with the security element  1 , on one side and the support at the stator part  4 , or at the cap bearing  3  retained by this, on the other side, and in an advantageous manner has a corresponding sliding face  2 . 4  at its front face facing towards the stator part  4  or cap  3 , and a stop buffer  2 . 1 ;  2 . 2 . projecting axially relative to its front face facing towards the securing element  1  or elastic element  1 . 3 ;  1 . 4 , by means of which the elastic element  1 . 3 ;  1 . 4 , particularly the free ends of its elastic limbs  1 . 3  or  1 . 4 , can be elastically pushed away in an axial direction. 
     As can be seen particularly from  FIG. 5 , the maximum axial elastic course can be simply defined due to the axial height of the stop buffer  2 . 1  or  2 . 2  compared with the baseplate  2 . 5  or  2 . 6 , acting during axial slack compensation as an axial stop for the expanding fingers  1 . 1  or  1 . 2 , that in an undeflected state lie in one plane with the elastic limbs  1 . 3  or  1 . 4 . 
     For mutual alignment of the intermediate disk  2  on one side and of the securing element  1  on the other side with the elastic limbs  1 . 3  or  1 . 4 , particularly in a manner advantageous for a simple plug-in assembly, the intermediate disk  2  has an axially projecting alignment piece  2 . 3  that during operation is arranged between the free ends of the elastic limbs  1 . 1  and  1 . 2 . 
     In a manner advantageous for production and assembly, as can be particularly seen from  FIG. 3 , the securing element  1  with its expanding fingers  1 . 1  or  1 . 2  and the elastic element  1 . 3 ;  1 . 4  with its elastic limbs  1 . 3  or  1 . 4  consist, by means of a yoke joint  1 . 5 , of a part pressed as a single piece from sheet metal, and the intermediate disk  2  including the stop buffer  2 . 1  or  2 . 2  and the alignment piece  2 . 3  consists of a single-piece, particularly injection molded, plastic part. 
     To reduce the cost in terms of production and components used to compensate the axial slack of a rotor shaft  5  in relation to a stator part  4 , an axial securing element  1  fixed onto the rotor shaft  5 , particularly in the form of a radially attachable expanding ring  1 . 1 ;  1 . 2 , is integrated with an elastic element  1 . 3 ;  1 . 4  which can be pressed axially in an elastic manner against the stator part  4  in order to compensate for axial slack, said elastic element in particular having the form of elastic limbs  1 , 3 ;  1 . 4  pressed in a single piece; an intermediate disk  2  with axial stop buffers  2 . 1 ;  2 . 2  which press against the elastic element  1 . 3 ;  1 . 4  on the one front face and one sliding surface  2 . 4  in relation to the stator part  4 , especially the front surface of a sliding bearing  3 , on the other front face guarantees an especially operationally reliable compensation of axial slack with a definable elastic course.