Abstract:
A rear wheel suspension for a vehicle, in particular a two-wheeled vehicle, specifically a bicycle ( 2 ) which is designed for a particularly great spring travel, comprises a pivot element ( 18 ) which is connected to a frame element ( 12 ) of the vehicle via a principal swivel joint ( 16 ), a swing arm rear suspension ( 6 ) which is connected to the pivot element ( 18 ) via an auxiliary pivot ( 20 ), a deflection element ( 46 ) which is pivotally mounted on a frame element ( 12 ), a hock absorber/spring element ( 52 ) which is mounted on the one hand on a frame element ( 14 ) and on the other hand on the deflection element ( 46 ), wherein the deflection element ( 46 ) is kinematically coupled to the swing arm rear suspension ( 6 ) via a pivotally mounted connecting element ( 38 ) and to the pivot element ( 18 ) via a pivotally mounted coupling element ( 60 ) in such a way that the end of the pivot element ( 18 ) facing the swing arm rear suspension ( 6 ) is pulled upwards on deflection of the rear wheel ( 8 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a rear wheel suspension for a vehicle and to a vehicle with a rear wheel suspension of this type. The vehicle is, in particular, a two-wheeled vehicle, specifically a bicycle. 
       BACKGROUND OF THE INVENTION 
       [0002]    More and more bicycles have not only a sprung fork but also a sprung rear section. With rear wheel spring suspension of this type, the design requirements can well exceed those of a motorcycle. In contrast to a motorcycle, the chain of the chain drive is tensioned abruptly rather than continuously in the case a bicycle. Furthermore, a cyclist does not sit still on the seat, particularly when travelling over hilly terrain, and this can amplify undesirable vibrations of the spring system. In particular, when riding uphill “out-of saddle” high-amplitude vibrations or movements at the rear suspension may occur. In addition, the distance between bottom bracket and rear wheel axle changes during deflection in many bicycle suspension designs. As a result, depending on the design parameters of the rear suspension and the chosen gear, the chain is more or less tensioned, elongated or shortened, and the crank and the pedals tend to swivel back or forward somewhat under load. To minimise this so-called pedal kickback, diverse spring designs have already been conceived, which range from a simple driving swing arm through a supported single bar mechanism to what is known as the four-bar mechanism, specifically in the variant of what is known as the Horst link rear section (see, for example, WO 93/13974). 
         [0003]    A common drawback of all these systems is that the achievable spring travel is generally restricted to a certain maximum value, if complex special solutions with other specific drawbacks are to be avoided. This is particularly of relevance for new-generation mountain bikes with comparatively big wheel diameters, for example 29 inches instead of the more common 26 inches. 
       SUMMARY OF THE INVENTION 
       [0004]    The object of the present invention is to provide a rear wheel suspension of the type mentioned at the outset which provides a particularly great spring travel while still being of simple design and while providing a large degree of freedom in choosing suitable wheel diameters. In addition, the rear wheel suspension should allow balanced performance and, in particular, spring characteristics in different travel situations, in particular in the off-road area. Furthermore, the rear wheel suspension should allow straightforward adjustment or adaptation of the responsiveness or other parameters to individual cyclist requirements while at the same time meeting the most stringent requirements in running gear robustness. A further requirement is to avoid sensible pedal kickback or kickforth effects and the like. 
         [0005]    This object is achieved according to the invention with a rear wheel suspension having the features of claim  1 . 
         [0006]    The rear wheel suspension accordingly comprises a pivot element which is connected to a frame element of the vehicle via a principal swivel joint, a swing arm rear suspension which is connected to the pivot element via an auxiliary pivot, a deflection element which is pivotally mounted on a frame element, a shock absorber/spring element which is mounted on the one hand on a frame element and on the other hand on the deflection element, wherein the deflection element is kinematically coupled to the swing arm rear suspension via a pivotally mounted connecting element and to the pivot element via a pivotally mounted coupling element in such a way that the end of the pivot element facing the swing arm rear suspension is pulled upwards on deflection of the rear wheel. 
         [0007]    Particularly in the case of a bicycle, the frame element to which the pivot lever is hingedly linked via the principal swivel joint may be, in particular, a seat tube carrying a bicycle seat or a separate support tube between the front wheel steering link and said principal swivel joint, the support tube supporting a seat tube of this type. The principal swivel joint is preferably arranged at the lower end of the seat or support tube. The deflection element is preferably also pivotally hingedly linked to the same seat or support tube, preferably above the principal swivel joint. The spring/shock absorber element, on the other hand, is preferably fixed to a bicycle frame element located further forward in the direction of travel. The connecting element is preferably arranged above the pivot lever and, in particular, above the swivel point of the deflecting lever. 
         [0008]    Advantageously, the pivot element is formed substantially as a straight rod at the front end of which the principal swivel joint is arranged and at the rear end of which the auxiliary swivel joint is arranged. 
         [0009]    In a particularly expedient embodiment, the deflection element comprises an upper lever arm and a lower lever arm which is rigidly connected thereto, the deflection element being connected to the frame element via a swivel joint arranged in the region of the connection between the upper lever arm and the lower lever arm. 
         [0010]    In an expedient development, the swivel joint connecting the deflection element to the frame element is arranged above the principal swivel joint. 
         [0011]    In addition, the connecting element is preferably connected to the upper lever arm via a swivel joint. 
         [0012]    In an advantageous embodiment, the shock absorber/spring element is at the same time also hingedly linked via the swivel joint connecting the connecting element to the upper lever arm. 
         [0013]    Advantageously, the coupling element is connected on the one hand to the lower lever arm via a swivel joint and on the other hand to the pivot element via a swivel joint. 
         [0014]    Expediently, the swivel joint connecting the coupling element to the pivot element is arranged in a central region of the pivot element between the principal swivel joint and the auxiliary swivel joint. 
         [0015]    In an advantageous embodiment, moreover, the coupling element is formed substantially as a straight rod at the upper end of which is arranged the swivel joint for connection to the lower lever arm and at the lower end of which is arranged the swivel joint for connection to the pivot element. 
         [0016]    In a preferred embodiment, the connecting element is connected to the swing arm rear suspension via a swivel joint arranged above the auxiliary swivel joint. 
         [0017]    In an advantageous variant, the swing arm rear suspension comprises a triangular frame with a chain stay, a seat stay and a connecting stay connecting the chain stay to the seat stay. The seat stay is located above the chain stay, in other words is located closer to the seat than the chain stay which extends approximately level with the drive chain. 
         [0018]    In an advantageous embodiment, the principal swivel joint, the auxiliary swivel joint and optionally the swivel joint connecting the rear wheel stay to the connecting element lie outside the outer circumference of the rear wheel. Expediently, this applies to all practical spring travels. 
         [0019]    If, for all practicable spring travels, the auxiliary swivel joint is located outside the outer circumference of the rear wheel, a particularly preferred variant becomes possible in which the auxiliary swivel joint is simultaneously constructed as a bottom bracket for a pedal crank drive. Therefore, the bottom bracket is not located on the main frame of the bicycle but forms a unit with the resiliently mounted swing arm rear suspension. As a result, the distance from the rear wheel axle to the bottom bracket does not change on deflection, as with a simple drive rocker. Therefore, the available chain length remains constant over the whole spring travel, and the system does not experience sensible pedal movements, like kickback or the like. The spring characteristic is thus unaffected by the chain tension. Nevertheless, the multi-jointed suspension or support for the rear section makes it possible to adjust a particularly advantageous wheel deflection curve for the rear wheel with sensitive responsiveness of the spring suspension. In contrast to systems with simple drive rockers, the tendency to rock can be effectively avoided, without the overall spring suspension becoming too stiff. 
         [0020]    In an advantageous embodiment, the rear wheel suspension is designed and adjusted in such a way that the rear wheel axle moves along an S-shaped (or backward S-shaped, depending on direction of view) wheel deflection curve on deflection of the rear wheel. The term wheel deflection curve refers to the trajectory over which the rear wheel axle moves during deflection relative to the vehicle frame. 
         [0021]    It is particularly advantageous if the distance from the rear wheel axle to the principal swivel joint (and therefore to the main frame), connecting the frame to the pivot lever, increases continuously during deflection of the rear wheel, at least during the final section of the deflection, in particular during the final half of the corresponding spring travel. 
         [0022]    The rear wheel suspension described here is most particularly suitable for a bicycle, but may in principle also be used on a motocross or off-road motorcycle or a general road motorcycle, with slight modifications which are within the purview of the person skilled in the art. In a particularly advantageous embodiment of this variant the chain of the chain drive driving the rear wheel is conducted around a shaft or an intermediate shaft whose axle is located along the lines of the bottom bracket axis in the case of a bicycle, as described above. 
         [0023]    An embodiment of the invention is described in more detail with reference to drawings which are highly schematic views, are not to scale and in some cases omit a few components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a side view of a sprung rear wheel suspension of a bicycle in the unloaded state, 
           [0025]      FIG. 2  shows the rear wheel suspension according to  FIG. 1  in the deflected state, and 
           [0026]      FIG. 3  is an exploded perspective view of the rear wheel suspension according to  FIG. 1  and  FIG. 2 . 
       
    
    
       [0027]    Like parts are provided with like reference numerals in all figures. 
       LIST OF REFERENCE NUMERALS 
       [0028]      
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                 2 
                 bicycle 
               
               
                 4 
                 bicycle frame 
               
               
                 6 
                 swing arm rear 
               
               
                   
                 suspension 
               
               
                 8 
                 rear wheel 
               
               
                 10 
                 direction of travel 
               
               
                 12 
                 support tube 
               
               
                 14 
                 lower tube 
               
               
                 16 
                 swivel joint 
               
               
                 18 
                 pivot element 
               
               
                 20 
                 swivel joint 
               
               
                 22 
                 triangular frame 
               
               
                 24 
                 chain stay 
               
               
                 26 
                 seat stay 
               
               
                 28 
                 connecting stay 
               
               
                 29 
                 rear wheel bearing 
               
               
                 30 
                 rear wheel shaft 
               
               
                 32 
                 arrow 
               
               
                 34 
                 arrow 
               
               
                 36 
                 swivel joint 
               
               
                 38 
                 connecting element 
               
               
                 40 
                 arrow 
               
               
                 42 
                 swivel joint 
               
               
                 44 
                 upper lever arm 
               
               
                   
                 (stay) 
               
               
                 46 
                 deflection element 
               
               
                   
                 (lever) 
               
               
                 48 
                 arrow 
               
               
                 50 
                 swivel joint 
               
               
                 51 
                 arrow 
               
               
                 52 
                 shock 
               
               
                   
                 absorber/spring element 
               
               
                   
                 (MacPherson strut) 
               
               
                 54 
                 swivel joint 
               
               
                 56 
                 lower lever arm 
               
               
                 58 
                 swivel joint 
               
               
                 60 
                 coupling element 
               
               
                 62 
                 swivel joint 
               
               
                 64 
                 wheel deflection 
               
               
                   
                 curve 
               
               
                 66 
                 rear wheel axle 
               
               
                 68 
                 bottom bracket shaft 
               
               
                 70 
                 bottom bracket 
               
               
                 72 
                 pedal crank 
               
               
                 74 
                 chain drive 
               
               
                 76 
                 bottom bracket axle 
               
               
                 78 
                 dropout 
               
               
                 80 
                 hoop 
               
               
                 82 
                 bottom bracket 
               
               
                   
                 housing 
               
               
                 84 
                 pivot bearing 
               
               
                   
                 housing 
               
               
                 86 
                 bearing recess 
               
               
                 88 
                 bearing recess 
               
               
                 90 
                 bearing recess 
               
               
                 92 
                 connecting rod 
               
               
                 94 
                 bearing recess 
               
               
                 96 
                 bearing recess 
               
               
                 98 
                 angle 
               
               
                 100 
                 angle 
               
               
                 102 
                 angle 
               
               
                 104 
                 angle 
               
               
                   
               
             
          
         
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    The side view in  FIG. 1  shows a detail of a bicycle  2  having a sprung swing arm rear suspension  6  mounted on a bicycle frame  4 . The bicycle frame  4  is basically composed of pairs of parallel tubes (for example plastic or metal tubes), some of these pairs lying in a first frame plane and the others lying in a second frame plane parallel thereto. In  FIG. 1 , the tubes of the second frame plane are covered by the tubes of the first frame plane. Connecting stays, which extend perpendicularly thereto and are also invisible in  FIG. 1 , are located between the two frame planes. Similarly, the swing arm rear suspension  6  is composed at least in part of pairs of components which are arranged in parallel or symmetrically to one another,  FIG. 1  showing only the part of these components located in front of the rear wheel  8  whilst the other part is concealed. 
         [0030]    To simplify interpretation, reference will occasionally be made only to the components which are visible in  FIG. 1 . In the case of paired components, equivalent statements will apply to the others. The terms “front” and “rear” used in the present description conventionally refer to the direction of travel  10  of the bicycle  2 . The terms “top” and “bottom” refer to the conventional operating position of the bicycle  2  on level ground, and the same applies to the relative positions “above” and “below”. 
         [0031]    The bicycle frame  4  of the bicycle  2  comprises a pair of support tubes  12  which are orientated approximately vertically and optionally also extend obliquely, the support tubes  12  at their upper end either carrying a bicycle seat (not shown here) directly or supporting a seat tube which carries the bicycle seat. In addition, the bicycle frame  4  comprises a pair of approximately diagonally, and optionally also horizontally orientated lower tubes  14 . The respective lower tube  14  is connected at its lower end to the lower end of the support tube  12  allocated thereto, in particular is welded thereto. Alternatively, the bicycle frame  2  may also be designed as a tube or rod system produced in one piece. 
         [0032]    In the region of the joint between support tube  12  and lower tube  14  there is a swivel joint  16  (principal swivel joint) on which a pivot element  18  (pivot lever) can be pivotally fixed by its front end. The swivel or pivot axis of the swivel joint  16  is orientated perpendicularly to the frame plane of the bicycle frame  4  and, in  FIG. 1 , is perpendicular to the plane of the drawing. At the rear end of the pivot element  18  there is a further swivel joint  20  (auxiliary swivel joint) with a swivel axis which is orientated parallel to the swivel axis of the swivel joint  16  and to which the actual swing arm rear suspension  6  is hingedly linked. The swing arm rear suspension  6  comprises two rigid triangular frames  22  which are located symmetrically on each side of the rear wheel  8 , again only one of the two triangular frames  22  in turn being shown in the view in  FIG. 1 . 
         [0033]    The respective triangular frame  22  comprises a chain stay  24  which extends approximately horizontally, a seat stay  26  which extends substantially obliquely thereto and a connecting stay  28 , which are arranged in a rigid triangular configuration and are connected to one another. The rear wheel bearing  29  (shaft bearing) for the rear wheel shaft  30  is located in the region of the connection between the rear end of the chain stay  24  and the rear end of the seat stay  26 . The connecting stay  28  connects the front end of the chain stay  24  in the region of the swivel joint  20  to the central or front region of the seat stay  26 . Overall, therefore, the triangular frame  22  can be pivoted as a rigid unit with the rear wheel bearing in the direction of the arrow  32  about the swivel joint  20  arranged at the rear end of the pivot element  18 , the pivot element  18  in turn being capable of pivoting at its front end via the swivel joint  16  in the direction of the arrow  34  about its suspension point on the vehicle frame  4 . 
         [0034]    However, the above-described pivoting movements cannot be performed completely freely and independently of one another, but are subject to some constraints: 
         [0035]    At the front end of the respective seat stay  26 , the rear end of a connecting element  38  (connecting lever) is in fact hingedly linked so as to pivot in the direction of the arrow  40  via a further swivel joint  36 . Just like the swivel axes of the swivel joints to be described hereinafter, the swivel axis of the swivel joint  36  is orientated parallel to the swivel axis of the swivel joint  16 . The front end of the connecting element  38  formed substantially as a straight rod is in turn connected so as to pivot in the direction of the arrow  48  via a swivel joint  42  to the upper lever arm  44  of a deflection element  46  (deflecting lever) formed in the manner of a rocker. The deflecting lever  46  is in turn connected so as to pivot in the direction of the arrow  51  at the lower end of the upper lever arm  44  via a swivel joint  50  to the pair of support tubes  12  of the bicycle frame  4 . 
         [0036]    Furthermore, the rear end of a shock absorber/spring element  52  is pivotally fastened to the swivel joint  42 . The front end of the shock absorber/spring element  52  is pivotally fixed via a further swivel joint  54  to a frame element of the bicycle frame  4 , for example to the lower tube  14  or to a support stay branching from the lower tube  14  (not shown in detail here). The shock absorber/spring element  52  formed, for example, in the manner of a conventional hydraulic shock absorber provides the desired restoring force during deflection of the rear wheel  8  and at the same time absorbs the associated vibratory processes. 
         [0037]    In addition, the deflection element  46  comprises a lower lever arm  56  which is rigidly connected to the upper lever arm  44  and is therefore also pivotally hingedly linked via the swivel joint  50  to the support tube  12  of the bicycle frame  4  so that a pivoting movement imposed on the upper lever arm  44  is transferred to the lower lever arm  56  by means of the rigid coupling. At the lower end of the lower lever arm  56  there is a swivel joint  58  to which the upper end of a coupling element  60  (coupling lever) formed substantially as a straight rod is hingedly linked. The lower end of the coupling element  60  is in turn pivotally connected via a swivel joint  62  to the central region (or also to the rear end region located in the vicinity of the swivel joint  20 ) of the pivot element  18 . 
         [0038]    As a result, during the deflection of the rear wheel  8 , a pivoting movement of the swing arm rear suspension  6  is transferred to the deflection element  46  which, in turn, reacts via the coupling element  60  on the pivot element  18  carrying the swing arm rear suspension  6  and pulls it upwards (in the direction of the seat). In other words, this design produces a coupling between the deflection element  46  loaded with the restoring force of the shock absorber/spring element  52  and the pivot element  18  connecting the swing arm rear suspension  6  to the bicycle frame  4 . This results in a (backward) S-shaped wheel deflection curve  64 , indicated schematically in  FIG. 1 , for the rear axle  66  of the rear wheel  8 . 
         [0039]    The kinematics during the deflection of the rear wheel  8  are best illustrated by a comparison of  FIG. 1  with  FIG. 2 ,  FIG. 1  showing the unloaded state of the sprung rear wheel suspension and  FIG. 2  the state with maximum deflection. In an advantageous embodiment, the upper lever arm  44  of the deflection element  46  can move unobstructed past the upper extension of the support tube  12 , and this allows particularly long spring travel (for example 240 mm in the case of a 29-inch rear wheel rim). A change in the length of the connecting element  38 , which can be achieved relatively easily, results in greater opportunities for adjustment than in former systems. 
         [0040]    In a particularly expedient embodiment, all swivel joints, in particular the swivel joints  20  and  36 , as shown in  FIG. 1  and  FIG. 2 , are located outside the outer circumference of the rear wheel  8  in all possible spring travel positions. As a result, in particular, the swivel joint  20  between swing arm rear suspension  6  and pivot element  18  can be formed as a bottom bracket  70  which in the conventional manner transfers (human) driving force imposed on a bottom bracket bearing  68  by means of pedal cranks  72  to the rear wheel  8  via a chain drive  74  only shown quite schematically here. In this embodiment, the distance between the bottom bracket axle  76  and the rear wheel axle  66  does not change during deflection of the rear wheel  8 ; instead, it remains constant. A pivoting movement of the bottom bracket  70  about the swivel joint  16 , produced by the pivoting movement of the pivot element  18 , does not inconvenience the cyclist, provided that the length and the attack angle (pitch) of the pivot element  18  is not excessively great. The pedal kickback or kickforth during deflection of the rear wheel on account of the varying distance between bottom bracket axis and rear wheel axle therein, known from other designs, is therefore basically prevented. 
         [0041]    The exploded view in  FIG. 3  shows a specific embodiment of further details of the rear wheel suspension. In contrast to the basic sketch in  FIG. 1  and  FIG. 2 , the respective triangular frame  22  of the swing arm rear suspension  6  has not only one but two connecting stays  28  which provide increased robustness. The rear wheel shaft  30  is mounted, for example, in dropouts  78  of the seat stays  26  and/or the chain stays  24 . At their front ends projecting beyond the outer circumference of the rear wheel  8 , the two seat stays  26  are joined together by a U-shaped hoop  80  which carries the swivel joint  36 . The front ends of the chain stays  24 , which also project beyond the outer circumference of the rear wheel  8 , are conceived as bottom bracket housings  82  for accommodating the bottom bracket shaft (not shown here). 
         [0042]    In the assembled state, the bottom bracket shaft is placed through the right-hand and left-hand bottom bracket housing  82 , the central part of the bottom bracket shaft located therebetween simultaneously forming the swivel joint  20  for the rear end of the pivot element  18  surrounding it and formed as a bearing recess (bearing bush). The front end of the pivot element  18 , in the assembled state, similarly engages between the two joint bearing housings  84 , arranged at the respective connection of support tube  12  and lower tube  14  of the bicycle frame  4 , for the swivel joint  16  which is completed by a cardan shaft (not shown in  FIG. 3 ) which is placed through the two joint bearing housings  84  and through the corresponding bearing recess  86  (bearing bush) of the pivot element  18 . 
         [0043]    In the assembled state, the deflection element  46  is similarly mounted by means of a cardan shaft (not shown), which is placed through the bearing recess  88  and through the associated bearing recesses  90  in/on the support tube  12  in the swivel joint designated in its entirety as  50  on the support tube  12 , which is arranged above the swivel joint  16 . The distance between the swivel axes of the swivel joints  16  and  50  roughly corresponds to the distance between the swivel axes of the swivel joints  16  and  20  of the pivot element  18 . The two lever arms  44  and  56  of the deflection element  46  form an obtuse, almost flat (i.e. 180°) angle to one another. Since the deflection element  46  is fastened between the two support tubes  12 , it can easily adopt the position shown schematically in  FIG. 2  in the deflected state of the rear wheel suspension, in which position the upper lever arm  44  is located in front of the support tube  12  as viewed in the direction of travel  10 , whereas it is normally located behind it in the unloaded state. 
         [0044]    In the present embodiment, the connecting element  38  is formed by two connecting rods  92  which are connected by associated cardan shafts (not shown) at the rear end to corresponding bearing recesses  94  of the triangular frame  22  and at the front end to bearing recesses  96  of the upper lever arm  44  of the deflection element  46 , so that the swivel joints  36  and  42  merely indicated schematically in  FIG. 1  and  FIG. 2  are embodied. Alternatively, it is also conceivable to use only a single connecting rod  92 . Similarly, the coupling element  60  is produced by a coupling rod which is connected via a respective cardan shaft (not shown) to bearing recesses of the lower lever arm  56  to form the swivel joint  58  and to bearing recesses of the pivot element  18  to form the swivel joint  62 . The distance between the swivel axes of the swivel joints  42  and  50  (corresponding to the effective length of the upper lever arm  44 ) is approximately twice as great as the distance between the swivel axes of the swivel joints  50  and  58  (corresponding to the effective length of the lower lever arm  56 ). The swivel joint  62  is arranged approximately centrally between the swivel joints  16  and  20  on the pivot element  18 . 
         [0045]    The swivel joint  42  between the connecting element  38  and the upper lever arm  44  of the deflection element  46  simultaneously serves for the pivotal mounting of the shock absorber/spring element  52  at its rear end. As with the other, already described joints, the pivotal connection is brought about here by means of a cardan shaft placed through corresponding bearing recesses. At the front end, the shock absorber/spring element  52  is pivotally fixed in an associated swivel bearing  54  on the bicycle frame  4  of the bicycle  2 , and on a support stay  100  in this case. The details of the frame construction may differ markedly from the example shown here under certain circumstances. 
         [0046]    Important features of the rear wheel suspension described hereinbefore are, in particular, specific lengths of the deflection lever, pivot and connecting lever and also the distances between the pivot bearings and angular positions thereof, which will be described in more detail hereinafter. This results in the realization of both a progressive force application curve in the relationship of the force/spring travel of the rear wheel to the shock absorber/spring element  52 , also called a MacPherson strut, and a novel, backward S-shaped wheel deflection curve of the rear wheel relative to the frame. 
         [0047]    The force characteristic of the spring force acting on the rear wheel through the suspension system is determined by that of the MacPherson strut  52  and the kinematics of the deflection lever. Starting from a MacPherson strut  52  which has, for example, a steel spring with a fixed bias, and therefore a characteristic which is linear over the force/spring characteristic, the progression of the system is determined predominantly by the angle  98  of the stay  44  of the deflection lever  46  to the MacPherson strut  52  and by the angle  100  of the stay  26  to the connecting element  38  and also the angle  102  of the connecting element  38  to the stay  44  of the deflection lever  46 . 
         [0048]    In order to obtain the maximum progressivity of the system, the angle  98  in the (non-deflected) starting position of the system should be between 30 degrees and 45 degrees, the angle  100  between 140 degrees and 150 degrees, and the angle  102  between 120 degrees and 110 degrees, the angles  98  and  100  increasing during deflection and the angle  102  decreasing. 
         [0049]    An excessive progression of the overall system can be reduced by further preferred angular positions. In this case, the angle  98  in the starting position of the system should be between 40 degrees and 70 degrees, the angle  100  between 145 degrees and 170 degrees, and the angle  102  between 115 degrees and 95 degrees, the angles  98  and  100  increasing during deflection and the angle  102  decreasing. 
         [0050]    In a further progressivity which satisfies most demands of travel, this is only small in design. In this case, the angle  98 , in the starting position of the system, should be between 65 degrees and 80 degrees, the angle  100  between 165 degrees and 185 degrees, and the angle  102  between 95 degrees and 85 degrees, again the angles  98  and  100  increasing during deflection and the angle  102  decreasing. 
         [0051]    The backward S-shaped rear wheel deflection curve  64  which is desirable for the great spring travel and the favourable ride is determined by the arrangement of the pivot point  50  of the deflection lever  46 , the pivot point  16  of the connecting member  18 , the pivot point  20  of the swing arm rear suspension  6  relative to the connecting member  18  and the angular position  104  of the lever arms  44  and  56  of the deflection lever  46  and also the respective length thereof. The length of the connecting member  18  and the angular position thereof to the Y-axis of the imaginary coordinate system, starting from the zero position of the pivot point  16 , determine the maximum amplitude of the backward S-shaped wheel deflection curve. The connecting member  60  which, with its swivel points  58  and  62 , connects the deflection lever  46  to the connecting member  18  is crucial for the mode of operation of the overall system. Here again, the length of the connecting member  60  and also the position of the connecting point  62  on the connecting member  18  is decisive so that the change in the wheel axle point  66  relative to the pivot point  16  of the main frame  4  is determined as a function of the load on the rear wheel. 
         [0052]    A preferred arrangement of the overall system is described hereinafter, starting from a coordinate system with an X-axis and Y-axis, of which the origin is located at the swivel point  16  of the main frame  4  and a length in millimetres. In this case, the pivot point  50  of the deflection lever is in the range −30&lt;X&gt;+30 and +130&lt;Y&gt;+170. The length of the lever arm  44  is between 90 mm and 130 mm, more preferably between 100 mm and 120 mm. The length of the lever arm  56  is between 40 mm and 60 mm, more preferably between 45 mm and 55 mm. The angle  104  of the lever arms  44  and  56  of the deflection lever  46  is between 130 degrees and 160 degrees, more preferably between 138 degrees and 148 degrees. The length of the connecting member  18  is between 60 mm and 100 mm, more preferably between 70 mm and 90 mm, and the angular position thereof to the Y-axis starting from point  16  is between −140 degrees and −175 degrees, more preferably between −145 degrees and −160 degrees, so that the maximum amplitude of the backward S-shaped wheel deflection curve is produced. 
         [0053]    The length of the connecting member  60  is between 40 mm and 60 mm, more preferably between 45 mm and 55 mm. The position of the connecting point  62  is determined as a percentage based on the length of the connecting member  18 . Starting from the origin  16  of the coordinate system, the point  62  is between 35% and 65% of the length of the connecting member  18 , more preferably between 45% and 55%. 
         [0054]    The newly developed rear wheel suspension has been described in the present case for use in a bicycle (which is operated by muscle power), in particular a mountain bike or trekking bicycle. However, it is also suitable for motocross or off-road motorcycles with combustion or electric drive. In this case, the pedal crank drive is obviously dispensed with. Instead of the chain drive, a cardan drive or the like can then optionally also be provided. This does not affect the above-described principles of the rear wheel suspension.