Abstract:
Wheels for goods wagons with small and large diameters, in addition to wheel sets equipped with wheels of this type for running gear, which are dependent on a highly passive radial positioning when negotiating curves and must remain stable at high speed. The inventive wheel profile is characterized as a result of the relatively large entry radius into the transition area from the running surface to the wheel flange by a low equivalent conicity. This enables a quieter running of the wheel set when the latter is travelling in a straight line. In curves, there is a sufficient rolling circle differential, permitting less wear and tear.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to wheels for railway goods wagons of varying measuring circle diameters, and wheel sets for running gears having such wheels. 
   2. Description of Related Technology 
   UIC Instruction Sheet 510-2 VE, International Railway Union, Beuth-Verlag GmbH, 10787 Berlin, sets out the conditions for the construction and maintenance of wheels for passenger train and goods wagons used in international traffic. It covers wheel diameters from 330 to 1000 mm, and indicates for these the wheel set loads permissible in terms of the material loading of the wheel and rail. The profile of the wheel (running profile) is described in the UIC Instruction Sheet with reference to different areas. The running profile of the wheel exhibits an inner wheel rim or tire front face to which is connected the wheel flange. The flange of the running profile is described by the inner wheel flange flank, the top of the wheel flange and the outer wheel flange flank. The wheel flange passes into the groove of the running profile, to which is connected the running surface. This is followed by the inclination of the outer running surface section, the outer bevelling of the running profile and the outer wheel rim or tire front face. The running profile is further described by the wheel flange height, the wheel flange thickness, the wheel rim or tire width, the measuring circle diameter, the radii of the top of the wheel flange, the radius of the running profile groove and the angle of the outer wheel flange flank. The profile is always described in the solid coordinate system whose origin (y=0, z=0) lies in the measuring circle plane (750 mm from the central plane of the wheel set). 
   Reference is also made to the Decree concerning the Construction and Operation of Connecting Railways, in the wording of the corresponding Federal State BOA, the Railway Construction and Operating Order (EBO), the Railway Construction and Operating Order for Connecting Railways (model) (EBOA), the Regolamento Internazionale Carrozze (RIC) and the Regolamento Internazionale Veicoli (RIV). 
   There are different wheel profiles of prior art, examples of which include the wheel profile S1002 (UIC 510-1), which is commonly used in bogies for goods wagons with wheel sets of normal size, and wheel profile SBB32-3, which is used in preference in truck on train wagons with small wheel sets. Profiles with an extremely flat running surface are also known for achieving the flattest possible hunting movement. 
   The wheel profile S1002 is a profile that is adapted to a rail gradient of 1:40 and which is characterized in that during the wearing process it remains almost unchanged in shape over the running path, and varies only slightly in terms of its running characteristics. To this extent the profile S1002 may be regarded as a wearing profile. The flange angle of the wheel flange is 70°. The disadvantage of this profile is that it develops a slight difference in radius between the right and left wheel due to the minimal displacement in the wheel channel, particularly on rails with a built-in gradient of 1:20. This has a particularly negative effect in the case of running gears with non-self-steering axles, for example in Y25 bogies. Because of the absence of ΔR function, the wheel set is unable to develop sufficient steering force to force the bogie smoothly into the curve on contact with the wheel flange. As a result of contact with the wheel flange, jerking steering movements and hence high quasi-static transverse forces are experienced, which may easily exceed the limit values for route loading. This applies particularly to the negotiation of tight curves. A further disadvantage is the variable derivation of the ΔR function at a line gradient of 1:20. 
   The wheel profile SBB32-3 was developed specially for small wheel tread diameters, and again for truck on train wagons. In contrast to the profile S1002, it is characterized in particular by the steeper flank angle of 75° instead of 70°. The relevant area of the running surface has a flatter slope and hence a lower wheel tread difference than the profile S1002. The wheel flange width of 135 mm is identical to that of the S1002. The radius of 216 mm at entry into the slope of the wheel flange commences in the center of the measuring circle plane. After approx. 26 mm in the direction of the flange the radius of 216 mm passes into the radius of 17.7 mm, then passes into the radius of 13 mm after a further 7 mm. With a wheel flange thickness of 32.3 mm, the profile SBB32-3 also lies within the range of the profile S1002. 
   The disadvantage here is that in the case of the profile SBB32-3 there is hardly any self-controlling function of the wheel set because of the relatively small difference in radius between the right and left wheel due to the displacement of the wheel set in the wheel channel (ΔR function). A further disadvantage is the variable derivation of the ΔR function in the transition from the running surface to the wheel flange, which renders the use of larger wheel tread radius differences impossible. Because of the low conicity of the wheel profile, there is sufficient running stability in the straight line. The wheel profile is not dimensionally stable. 
   A further disadvantage of the above-mentioned wheel profiles lies in the fact that the Y/Q values are too high. 
   SUMMARY OF THE INVENTION 
   In one embodiment, the invention provides a wheel for goods wagons, with a measuring circle diameter of 330 mm to 760 mm, the wheel profile being defined by an inner wheel rim or tire front face, an inner wheel flange flank, a top of the wheel flange, an outer wheel flange flank, a groove of a running profile, a running surface, a gradient of an outer running surface section, an outer bevelling of the running profile, and an outer wheel rim or tire front face, wherein the wheel profile in the region of the groove of the running profile and of the running surface is described by the following coordinates (X 1 to 4 , Y 1 to 4 ) in a solid coordinate system whose origin (x=0, y=0) lies in a measuring circle plane, which coordinates lie between the ranges of values indicated: 
   
     
       
             
             
             
             
             
             
             
             
           
             
             
             
             
             
             
             
             
           
         
             
                 
                 
             
             
                 
               X max   
               X min   
               Delta X 
                 
               Y max   
               Y min   
               Delta Y 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
               X 1   
               −39.791 
               −43.979 
               4.189 
               Y 1   
               15.683 
               14.189 
               1.494 
             
             
               X 2   
               −29.109 
               −32.173 
               3.064 
               Y 2   
               3.823 
               3.459 
               0.364 
             
             
               X 3   
               −15.398 
               −17.018 
               1.621 
               Y 3   
               1.098 
               0.994 
               0.105 
             
             
               X 4   
               −4.042 
               −4.468 
               0.426 
               Y 4   
               0.223 
               0.201 
               0.021 
             
             
                 
             
           
        
       
     
   
   In another embodiment, the invention provides a wheel for goods wagons with a measuring circle diameter of 760 mm to 1000 mm, having a wheel profile defined by an inner wheel rim or tire front face, an inner wheel flange flank, a top of the wheel flange, a outer wheel flange flank, a groove of a running profile, a running surface, an inclination of an outer running surface section, an outer bevelling of the running profile, and an outer wheel rim or tire front face, wherein the wheel profile in the region of the groove of the running profile and running surface is defined by the following coordinates (X 1 to 4 , Y 1 to 4 ) in the solid coordinate system whose origin (x=0, y=0) lies in the measuring circle plane, which coordinates lie between the ranges of values indicated: 
   
     
       
             
             
             
             
             
             
             
             
           
             
             
             
             
             
             
             
             
           
         
             
                 
                 
             
             
                 
               X max   
               X min   
               Delta X 
                 
               Y max   
               Y min   
               Delta Y 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
               X 1   
               −37.311 
               −41.239 
               3.928 
               Y 1   
               14.157 
               12.808 
               1.348 
             
             
               X 2   
               −27.028 
               −29.873 
               2.845 
               Y 2   
               3.693 
               3.341 
               0.352 
             
             
               X 3   
               −13.175 
               −14.561 
               1.387 
               Y 3   
               0.954 
               0.863 
               0.091 
             
             
               X 4   
               −2.342 
               −2.589 
               0.247 
               Y 4   
               0.129 
               0.117 
               0.012 
             
             
                 
             
           
        
       
     
   
   The wheels according to the invention are intended in particular for wheel sets in running gears, which rely upon highly passive radial positioning when negotiating curves, and which must nevertheless remain stable at high speeds of travel. Because of the relatively large radius of entry into the transitional area from the running surface to the wheel flange, the wheel profile of the wheels is characterized by a low equivalent conicity. This provides quieter running of the wheel set whilst travelling in a straight line. In curves, however, there is sufficient wheel tread-differential. 
   This results in reduced wear and tear, particularly in regard to the wheel flange flanks. In the case of retreading it is not necessary to undercut as much volume as for conventional wheel profiles. 
   A decisive advantage of the wheel profile of the wheels according to the invention is that rails with gradients of both 1:20 and 1:40, but also rails with other gradients, can be negotiated to the optimum degree. The wheel profile contour selected, combined with the current rail profiles, e.g. UIC60, ensures continuous migrating wheel/rail contact points over a large area of the wheel profile during the transverse wheel set deflection. This also provides uniform wear reduction throughout the profile contour, i.e. the wheel profile shape of the wearing profile is more or less maintained. 
   For the wheel profile of the wheels according to the invention the design of the areas of the wheel profile which are described by the groove of the running profile and the running surface is a particularly decisive factor. The areas of the wheel profile which are described by the inclination of the outer running surface section and the outer bevelling of the running profile and by the outer wheel rim or tire front face may be designed steeper or flatter, depending on the existing superstructure conditions, such as switches, e.g. of a wing rail on a frog point, level crossings, pavement etc., and depending on the development of wearing of the wheel profile (e.g. incorrect wheel flange/hollow running). 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Two embodiments of the invention are described in detail in the following with reference to the drawing figures. 
       FIG. 1  shows the wheel profile of a wheel for goods wagons with a small wheel diameter, 
       FIGS. 2   a  to  2   c  show the profile description of the wheel profile in  FIG. 1  in the solid coordinate system, including the radii of the circle segments describing the profile, 
       FIG. 3  shows the wheel profile for wheels with a large diameter, and 
       FIGS. 4   a  to  4   c  show the profile description of the wheel profile in  FIG. 3  in the solid coordinate system, including the radii of the circle segments. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates the wheel profile for wheels with a small diameter, which is characteristic of small wheels with a diameter of 330-760 mm.  FIG. 2   a  shows, in tabular form, the individual coordinates and radii of an optimum profile for a diameter of 330-760 mm, in particular 380 mm, which the inventors have developed in a large number of tests and simulations, whilst  FIGS. 2   b  and  2   c  indicate ranges of values for the coordinates and radii. It has been shown that the advantages of the invention still pertain when the coordinates lie within the ranges of values indicated in  FIGS. 2   b  and  2   c.    
   The wheel profile for small wheels is described by ten ranges, each of which lies between points 1 to 11. The profile is described in the solid coordinate system, whose origin (y=0, z=0) lies in the measuring circle plane (750 mm from the central wheel set plane). The wheel profile described is determined for wheel sets which have a wheel size that must be adhered to according to the international regulations (RIC, RIV, UIC), particularly for a wheel size of between 14.21 and 14.26 mm. 
   The areas of the wheel profile that lie between points 1 and 2, 2 and 3, 3 and 4, 5 and 6, 6 and 7 and 7 and 8 are described by circle segments, which are formed from circles with the centers M 1  to M 6  and radii R indicated. The circle segments with the indicated centers and radii pass continuously into each other, i.e. there are no variabilities at the points. 
   The radii M 4 , M 5  and M 6 , which describe the circle segments between points 5 and 6, 6 and 7 and 7 and 8, are particularly decisive for the advantageous running characteristics. These areas lie in the groove of the running profile and running surface. 
   Radius R 16  of the circle about center M 4  lies in a tolerance range of between 15 mm and 18 mm, and runs into the flank area of the wheel flange at a distance of 30 mm to 32 mm measured from the point of wheel loading on the wheel flange. Radius R 83  about center M 5  lies in a tolerance range of 80 mm to 84 mm, in which the centers vary accordingly. Radius R 303  about center M 6  lies in a tolerance range of between 300 and 305 mm, and commences at a point from 4 mm to 6 mm from the center of the measuring circle, in which the centers vary accordingly. In the preferred embodiment the radii are 16 mm, 83 mm, and 303 mm. 
   The profile area between points 4 and 5 is described by a straight-line which intersects the x axis at an angle of 75° (angle of the outer wheel flange flank). However, the flank angle may also be below 70°. 
   Because of the relatively large radius R  303  about center M 6 , in the range of 300 to 305 mm, and because of the connecting radii about centers M 5  and M 4  of 80 to 84 mm and 15 to 18 mm respectively, combined with a reduced wheel size, a lower equivalent conicity is obtained when the wheel sets run out onto a straight line. On entering tight curves there is a relatively steep rise in the wheel profile contour where the wheel comes into contact with the wheel set at approximately 16 mm from the center of the measuring circle (diameter), viewed in the direction of the flange flank, this being due to the relatively small radius ranging from 80 to 84 mm about center M 5 . Therefore a sufficiently large ΔR function is generated to provide the wheel set, whilst running in curves, a correspondingly large setting moment due to the tangential longitudinal slip throughout the rail gradient range of 1:20 to 1:40 and beyond. The radius about center M 4  (15 mm to 18 mm) connecting to the radius about center M 5 (80 mm to 84 mm), on the transition to the flank surface inclined at 75°, is therefore larger than in the wheel profiles of prior art. When the wheel flange is contacted, a smoother behavior, without impact, is guaranteed. Consequently this area, with rail profile UIC60 (gradient 1:20 and 1:40) experiences a “more constant” first derivation of the ΔR function. Therefore there can be no two-point contacts between the wheel tire profile and the rail profile either. 
   When entering curves, the relatively small radius R  83  about center M 5 , which connects to radius R  303  about center M 6 , results in a steep increase in the ΔR function if the wheel flange comes into contact with the rail head. This in turn results in a positive steering moment of the wheel set, and hence to better radial setting of the wheel set. Radius R 16 , connecting to radius R 83 , at the transition to the flank surface inclined at 75°, allows smooth contact, without impact, between the wheel flange and the rail head if there are any irregularities in the curving of the rail that may occur in the case of major track defects. The slightly higher equivalent conicity resulting from the higher ΔR function when negotiating curves presents no problem because tight curves are negotiated at lower speeds, and stable running conforming to the predetermined routing is achieved because of the centrifugal force of the goods wagon. 
     FIG. 3  illustrates the wheel profile for large wheels with a large diameter, which is characteristic of wheels with diameters ranging from 760-1000 mm, in particular 920 mm.  FIG. 4   a  shows, in tabular form, the individual coordinates and radii of an optimum profile for a diameter of 920 mm, which the inventors have developed in a large number of tests and simulations, whilst  FIGS. 4   b  and  4   c  indicate ranges of values for the coordinates and radii. It has been shown that the advantages of the invention are enjoyed even when the coordinates lie within the ranges of values indicated in  FIGS. 4   b  and  4   c.    
   Because of the larger diameter, values other than those for the wheel profile for small wheels, described with reference to  FIGS. 1 and 2   a  to  2   c , are obtained for the coordinates of the points and radii. Here too the ranges of wheel profile between points 6 and 7, 7 and 8 and 8 and 9, which are described by the circles of radii M 5 , M 6  and M 7 , are particularly decisive. 
   Radius R 16  of the circle about center M 5  lies within a tolerance range of between 15 and 18 mm, and runs into the flank surface of the wheel flange at a distance of 36 to 39 mm, measured from the point of pressure between the wheel and wheel flange. Radius R 83  about center M 6  lies within a tolerance range of between 80 and 84 mm, in which the centers then vary accordingly. Radius R 303  about center M 7  lies within a tolerance range of between 300 and 305 mm, and commences from 1 to 2 mm from the center of the measuring circle, in which the centers then vary accordingly. In the preferred embodiment the radii are 16, 83 and 303 mm. In contrast to the embodiment shown in  FIGS. 1 and 2 , the angle of the outer wheel flange flank between points 5 and 6 is 70°. 
   When entering tight curves there is a relatively steep increase in the wheel profile contour when the wheel contacts the wheel set at only approximately 13 mm from the center of the measuring circle, viewed in the direction of the flange flank. If the coordinates of points 6, 7, 8 and 9 in particular lie within the ranges of values indicated, the same advantages described with reference to  FIGS. 1 and 2   a  to  2   c  for smaller wheels are also provided for larger wheels. 
   In this regard reference is therefore made to the description of the first embodiment.