Abstract:
An arrangement for axially supporting two jointly rotating components ( 2, 3 ) by way of a snap ring ( 6 ) having two displaceable impacting ends ( 6   a,    6   b ), which are separated from each other by a peripheral gap ( 7 ), and which can move in the region of a radial spring path. The snap ring ( 6 ) is inserted into an annular groove of the supporting component ( 2 ). The supporting component ( 3 ) comprises one ramp ( 8, 9 ) in the region of the radial spring path of the impacting ends ( 6   a,    6   b ) of the snap ring ( 6 ).

Description:
This application is a national stage completion of PCT/EP2004/000296 filed Jan. 16, 2004 which claims priority from German Application Serial No. 103 02 075.6 filed Jan. 21, 2003. 
   FIELD OF THE INVENTION 
   The invention relates to an arrangement for axial support of two jointly rotating components by means of a snap ring. 
   BACKGROUND OF THE INVENTION 
   The axial support by way of a snap ring of components, for example, of a ball bearing or a gear wheel, jointly rotating upon a shaft, is already known. The snap ring is not closed, but has a gap extending in peripheral direction and, therefore, its outer or inner diameter can be changed by elastic deformation. The snap ring is held on the shaft in a narrowly tolerated annular groove. The snap ring can also be inserted in an annular groove of a hollow part such as a hole. The snap ring is conventionally secured on its groove only by its tension. Under certain operating conditions, like high peripheral speeds associated with vibrations, said spring tension does not suffice to keep the snap ring in its groove. On the contrary, it can happen that the snap ring emerges from its groove and thus can no longer fulfill its function of axial fixing function. This can result in sensitive damages. 
   The object of this invention is, therefore, to provide for an arrangement of the above mentioned kind of snap ring securing device which prevents the snap ring from leaving its annular groove with no further added expenses resulting. 
   According to the invention, ramps are provided in the area of the impacting ends which prevent the snap ring from springing in or out in the area. The impacting ends are thus secured with a positive fit against radial movements. Depending on whether the snap ring is situated in a hole or on a shaft, the ramps are disposed either radially within or radially without the impacting ends. 
   SUMMARY OF THE INVENTION 
   With each impacting end, a single ramp is coordinated, which presents a springing in or out of each impacting end in radial direction. Between the two impacting ends, it is advantageous to situate one stop in the peripheral gap which presents a twisting of the snap ring. Thereby the impacting ends of the snap ring are kept in the sphere of action of the ramps and the snap ring can no longer spontaneously leave the annular groove. The stop between the two impacting ends can be advantageously designed as knubs. Knubs and ramps have an axial extension in the area of the axial thickness of the snap ring, preferably somewhat smaller. It is further advantageous that the components be designed as sheet metal components and the ramps and/or the knubs be stamped from the sheet metal component or components. Such a stamping is practically neutral in cost, since the stamping tool concerned requires only a small change. It is further advantageous that the ends of the snap ring be designed before the impacting ends non-torsionally around an axis extending in peripheral direction. This is of advantage in the assembling of the snap rings mounted in the annular groove since the snap ring ends slide over the ramps during the assembly becoming axially twisted and finally snap in or lock behind the ramps. It is an advantage of the snap ring if per se too non-torsional to reduce the cross-section in radial direction. By way of this simple step, the desired torsional stiffness is obtained in the area of the impacting ends. Finally, it is advantageous that the supported and/or to be supported sheet metal components are parts of a multi-disc clutch, that is, disc carriers. Snap rings are used under extremely limited installation conditions for axial fixing of a disc set under axial pressure and are also, at the same time, subjected to vibration stresses. The inventive securing of the snap ring by way of ramps and knubs is of particular advantage in this embodiment of a multi-disc clutch. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  is an axial section through a multi-disc clutch of a motor vehicle transmission; 
       FIG. 2  is a view in axial direction on the multi-disc clutch according to  FIG. 1 ; 
       FIG. 3  is a partial view in perspective of a snap ring securing device; 
       FIG. 4  is a simplified transverse section along the line IV-IV in  FIG. 3 ; 
       FIG. 5  is a partial view on the component to be supported with a snap ring securing device; 
       FIG. 6  is a section along line VI-VI in  FIG. 5 ; 
       FIG. 7  is a snap ring; and 
       FIG. 8  is a detail X from  FIG. 7 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a multi-disc clutch  1 , that is, a shifting element of an automatic transmission for a motor vehicle. The multi-disc clutch  1  has one outer disc carrier  2  and one inner disc carrier  3 , which is non-rotatably connected with the outer disc carrier  2 . Within the outer disc carrier  2  is situated one disc set  4  which is pressed against a snap ring  13  by a hydraulically actuatable gearshift piston  5 . 
   The snap ring  13  is held in an annular groove of the outer disc carrier  2  and dimensioned so as to need no additional securing. The inner disc carrier  3  has one front flange  3   a  which is situated directly adjacent the snap ring  13 , but without contact, and is fixed axially in one direction by a secured snap ring  6 . In the opposite direction, the front flange  3   a  abuts preferably on three front surface areas  2   b  of the outer disc carrier  2 . The snap ring  6 —contrary to the snap ring  13 —is of lesser dimensions for reasons of space and function and, to that extent, is in danger of coming out. Therefore, it has a securing device described below. 
     FIG. 2  shows a view in axial direction on the inner disc carrier  3  and the snap ring  6  which is overlapped by the outer disc carrier  2  by trapezoidally designed crimpings  2   a  (disc toothing of the outer disc carrier  2 ). The inner disc carrier  3  is secured opposite the outer disc carrier  2  via radial projections  3   b  axially in one direction and by the snap ring  6  in the other direction. In the area X, surrounded by a dotted line, the snap ring  6  is split (as shown as detail X in perspective representation in  FIG. 3 ) and only for the part  3  in  FIGS. 5 and 6 . 
   In a perspective representation,  FIG. 3  shows one section in the area of the detail X of  FIG. 2 . The snap ring  6  has two impacting ends  6   a ,  6   b  between which extends a peripheral gap  7 . The snap ring  6  is overlapped by the radial crimpings  2   a  and held in axial direction. Radially within the impacting ends  6   a ,  6   b  so-called support ramps  8 ,  9  are situated upon the inner disc carrier  3 . In the area of the peripheral gap  7 , a knub  10  of approximately circular design is situated on which abuts the impacting end  6   a . A peripheral gap x remains between the non-abutting side of the knub  10  and the other impacting end  6   b.    
     FIG. 4  shows a simplified partial section along the line IV-IV in  FIG. 3 , that is, radially situated within the impacting end  6   b  through the impacting end  6   b  and the ramp  9 . The ramp  9  forms an interruption and is stamped from the inner disc carrier  3  designed as a sheet metal part that is integral therewith. In the outer disc carrier  2 , an annular groove  11  is located in which is inserted and axially fixed the snap ring  6  with its impacting ends  6   a ,  6   b . Against the area of the snap ring  6  or  6   b  radially projecting inwardly from the annular groove  11 , the front flange  3   a  leans with a front face  3   c  so that the inner disc carrier  3  is supported in axial direction. 
     FIG. 5  shows a partial view of the inner disc carrier  3  in the area of the detail X in  FIG. 2 , that is, the approximately rectangularly designed ramps  8 ,  9  and the knubs  10  situated between the ramps but radially somewhat outside. 
     FIG. 6  shows a section along the line VI-VI in  FIG. 5  wherein the splines of the ramp  9  and of the knub  10  can be seen. The axial extension a of knubs  10  and the axial depth b of the ramp  9  or  8  are in the area of the axial extension of the snap ring  6 . The knub  10  is also stamped from the sheet metal component  3 . To that extent, both the ramps  8 ,  9  and the knubs  10  can be produced easily and without added working operation integral with the disc carrier  3 . The axial depth a of ramps  8 ,  9  and the axial depth b of the knubs  10  are preferably smaller than that of the snap ring  6 . 
     FIG. 7  shows the snap ring  6  as a separate component. Its radial extension is designated with B. The snap ring has throughout its periphery this dimension B—with the exception of two recesses  12 , which are situated in the area of the peripheral gap  7  and of the impacting ends  6   a ,  6   b.    
     FIG. 8  shows a detail X in the area of the peripheral gap  7  and of the recess  12  of  FIG. 7 . Both impacting ends  6   a ,  6   b  form the peripheral gap  7  between them. The impacting ends  6   a ,  6   b  have the dimension B in the area of the peripheral gap. On the impacting end  6   a , on the side remote from the gap  7 , a recess  12  attaches itself, which results in a reduction of the height of the snap ring designed with C. In the area of this reduced cross-section is plotted a somewhat tangentially extending axis Y-Y which forms the torsion axis of the snap ring  6  in this area. 
   The function of the snap ring  6  is explained as follows: the snap ring  6  is first mounted, that is, threaded in the annular groove  11  ( FIG. 4 ). This takes place approximately up to the position shown in  FIG. 3 , that is, the impacting end  6   b  lies approximately flush with the ramp  9 . The other impacting end  6   a  obviously is not met in the annular groove, but somewhat radially within, that is, seen in axial direction before the ramp  8 ; the cross-section of the snap ring being axially twisted. In the embodiments according to  FIG. 8 , this means that the impacting end  6   a  is axially twisted around the torsion axis Y-Y opposite the cross-section designated with C. Accordingly, in order to adapt the torsional forces or torsional torques that appear, the snap ring cross-section has become correspondingly reduced (the snap ring cross-section thereby became torsion weaker) in the embodiment according to  FIG. 8 . In order finally to bring the axially twisted impacting end  6   a  to its position in the annular groove  11 , it is pressed radially outwardly rebounding to its axial twisting, according to  FIG. 4 , and is thus simultaneously snapped behind the ramp  8 . The radially inwardly springing out from the groove  11  is now blocked by the two ramps  8 ,  9 . In order that the snap ring  6  does not move in peripheral direction ad the impacting ends  6   a ,  6   b  would possibly be offset opposite the ramps  8 ,  9 , the knubs  10  are placed in the area of the peripheral gap  7  or between the ramps  8 ,  9 . Only a small peripheral play x ( FIG. 3 ) is thus possible, but it is selected so that the ramps  8 ,  9  lie always within the impacting ends  6   a ,  6   b.    
   The invention has been explained above with reference to one embodiment, namely, a multi-disc clutch with an outer and an inner disc carrier, that is, with a snap ring, which is located in a hole or a hollow cylindrical component. But it is also within the scope of the invention to mount the snap ring upon a shaft or upon the outer surface of a cylindrical component. In this case, the ramps would have to be disposed radially outside the snap ring to prevent the impacting ends from radially springing out. 
   REFERENCE NUMERALS 
   
       
         1  multi-disc clutch 
         2  outer disc carrier 
         2   a  crimping (disc toothing) 
         2   b  front face area 
         3  inner disc carrier 
         3   a  front flange 
         3   b  radial projection 
         3   c  front face 
         4  disc set 
         5  shift piston 
         6  snap ring (secured) 
         6   a  impacting end 
         6   b  impacting end 
         7  peripheral gap 
         8  ramp 
         9  ramp 
         10  knubs 
         11  annular groove 
         12  recess 
         13  snap ring (not secured)