Patent Publication Number: US-2015059612-A1

Title: Stone impact protection arrangement and rail vehicle with a stone impact protection arrangement

Description:
The invention is based on a stone impact protection arrangement for protecting at least one vehicle component which is arranged in the region of the underbody of a rail vehicle, in particular a wheelset shaft, having at least one resilient shielding element and at least one retention device which carries the shielding element. 
     The invention is further based on a rail vehicle which is for travel on track systems having a ballasted track and which has at least one vehicle component and one stone impact protection arrangement in the region of the underbody thereof. 
     When such vehicles are travelling, the problem often occurs that individual ballast stones, for a wide variety of reasons, are torn from the ballast bed and thrown upward when rail vehicles travel over them, such ballast stones being able to strike the underfloor region of the passing rail vehicle with great intensity and potentially causing damage at that location. It is also possible that installations of the track infrastructure may be damaged (for example, track switching means). This occurrence, as a result of those ballast stones which return to the track bed and bring about the disturbance of many additional ballast stones, may lead to a significant ballast slippage which is self-maintaining for a relatively long period of time. This phenomenon is appropriately known in technical circles as flying ballast, ballast projection or ballast impact. The problem of flying ballast occurs primarily when traveling over rail installations having a conventional ballasted track at travel speeds of more than 200 km/h. 
     In order to protect sensitive vehicle components, they are shielded against flying ballast with impact plates. Other sensitive components are accommodated in stable metal cases. Furthermore, flying ballast is counteracted by means of additional deflector plates in the region of the bogie. DE 10 2004 041 090 A1 shows such deflector plates. 
     The protection of wheelset shafts comprises, for example, resilient coatings with various materials or even coverings for the shafts with additional rubber-like materials. It is disadvantageous that the thick coating makes the inspection of the surface of the shaft more difficult and thereby also the maintenance of the rail vehicle. 
     An object of the invention is to provide a stone impact protection arrangement and a rail vehicle with a stone impact protection arrangement which prevents the damaging effect of ballast stones or other foreign bodies which are thrown upward in a simple and effective manner, but which allows simple inspection. 
     The object is achieved with the features of the independent claims  1  and  7 . Advantageous embodiments are set out in the dependent claims. 
     The stone impact protection arrangement according to the invention makes provision for a plurality of shielding elements which are constructed as flexurally resilient strips and which are retained at both respective end regions thereof by means of the at least one retention device. Each individual strip of the strips which are retained at the end regions thereof can resiliently absorb the energy of a stone impact in a particularly effective manner with the flexurally resilient central portion thereof. As a result of the use of a plurality of shielding elements which are constructed as flexurally resilient strips, a planar shielding structure can be formed. On the other hand, the redirection and possible subsequent occurrences of oscillation are limited to the strip which is affected by the impact of the ballast stone or other object. The retention of the strips in/on the at least one retention device is in particular intended to be understood to be a bearing in the sense of a fixed bearing and/or a movable bearing. 
     Such a stone impact protection arrangement has the advantage that it can be assembled and disassembled relatively quickly and therefore enables an inspection of the at least one component to be protected. 
     The flexurally resilient strips are preferably constructed as sheet metal strips formed from resilient metal sheets or as pultruded GRP plates (GRP: glass-fiber reinforced plastics material). 
     The stone impact protection arrangement can be used to protect one or more vehicle component(s) in the region of the underbody of the rail vehicle. However, the stone impact protection arrangement is in particular a stone impact protection arrangement for protecting a wheelset shaft of the rail vehicle. In this instance, a planar shielding structure formed by the flexurally resilient strips covers the covering face of the shaft (with the exception of narrow gaps between the strips) preferably over the entire surface. 
     Advantageously, the longitudinal axes of the strips are preferably retained so as to be orientated parallel with each other. The at least one retention device is therefore constructed to retain the longitudinal axes of the strips in a parallel manner. It is thereby possible to form in a simple manner a planar shielding structure which covers/shields the at least one vehicle component. In a central portion which extends transversely relative to the orientation of the strips over all these strips, the stone impact protection arrangement has a relatively homogeneous rigidity. In particular, there is provision for two retention devices to be provided, of which one retention device retains one end region and the other retention device retains the other end region of each of the strips, respectively. 
     According to a preferred embodiment of the invention, there is provision, in order to enable low-tension bending of the strips, for the retention devices to be constructed in a resilient manner and/or to be connected to each other in a resilient manner. 
     According to another preferred embodiment of the invention, there is provision for the at least one retention device to be a retention device for spaced-apart support of the strips with respect to the vehicle component to be protected. The spacing a between the strips and the surface of the component to be protected or the components to be protected is determined in accordance with the typically occurring kinetic energy of the objects and the rigidity of the strips. In order to adapt the rigidity, the geometry of the strip is constructed accordingly, for example, by means of at least one bead. 
     There is further advantageously provision for the at least one retention device to be able to be secured to the vehicle component which is constructed as a wheelset shaft by means of at least one clip, in particular a worm drive hose clip. Such a securing of the stone impact protection arrangement for the wheelset shaft has the advantage that it can be assembled and disassembled in a relatively rapid manner and therefore enables inspection of the at least one component to be protected. Retrofitting of existing shafts is also possible without structural changes to the wheelset. 
     In the rail vehicle according to the invention having a stone impact protection arrangement, there is provision for the stone impact protection arrangement to be a stone impact protection arrangement mentioned above. 
     The vehicle component to be protected is completely or at least partially covered by the stone impact protection arrangement. In this instance, the vehicle component in the region of the vehicle underbody is in particular a wheelset shaft. The covering face of the wheelset shaft is surrounded over the periphery by all of the strips of the stone impact protection arrangement, in each case with a radial spacing a. To this end, the strips have a corresponding curvature. 
     According to a preferred embodiment of the invention, there is provision for the retention device or the retention devices to be secured to the at least one vehicle component to be protected. Alternatively, the retention device or the retention devices may also be secured to at least one other vehicle component, preferably, an adjacent vehicle component. 
     According to another preferred embodiment of the invention, the strips of the at least one retention device of the stone impact protection arrangement are retained transversely relative to the travel direction of the rail vehicle. 
    
    
     
       An embodiment of the invention is explained in greater detail below with reference to the drawings, in which: 
         FIG. 1  is a schematic illustration of the operating principle of a stone impact protection arrangement, and 
         FIG. 2  shows a stone impact protection arrangement for protecting a wheelset shaft according to a preferred embodiment of the invention, 
         FIG. 3  is a sectioned illustration through the stone impact protection arrangement and the wheelset shaft along the line of section III-III of  FIG. 2 , and 
         FIG. 4  is a detailed illustration of the securing of the stone impact protection arrangement on the shaft. 
     
    
    
       FIG. 1  is a schematic illustration of the operating principle of a stone impact protection arrangement or a stone impact protection device  10  for protecting a vehicle component  12  of a rail vehicle which is not illustrated. The vehicle component  12  of the rail vehicle to be protected is in this example a wheelset shaft  14  of a wheelset of the rail vehicle. 
     The stone impact protection arrangement  10  comprises a plurality of shielding elements which are constructed as flexurally resilient strips  16 . These strips  16  are supported at the two end regions  18 ,  20  thereof which are arranged opposite each other in the longitudinal extent of the respective strip  16  in such a manner that the flexurally resilient strips  16  can bend in a central portion  22  in the direction of the component  12  to be protected, that is to say, in this instance radially in the direction of the shaft  14 . In this instance, the end regions  18 ,  20  are retained so as to be spaced apart with a spacing a with respect to the vehicle component  12 . In the non-deformed state, the strips  16  extend parallel with the rotation axis  24  of the shaft  14 . The strips  16  are, for example, constructed as sheet metal strips or sheet metal bars of a resilient metal sheet or as pultruded plates of GRP (GRP: glass-fiber reinforced plastics material). 
     A ballast stone  26  which has been thrown up from the ballasted track of a track installation over which a rail vehicle has just travelled or another object which moves in the direction of the component  12  (arrow  28 ) strikes one of the flexurally resilient strips  16  of the protection arrangement  10 . In the example shown, this object  26  strikes the central portion  22  of this one strip  16 . Since the flexurally resilient strips  16  are retained or supported at the end regions  18 ,  20  thereof which are opposite each other, the strips can give way in this central portion in a particularly highly resilient manner. The strip  16  can thereby absorb the kinetic energy of the object  26  in an effective manner by the resilient deformation. The resilient (elastic) deformation of the corresponding strip  16  is indicated by the dashed lines. A corresponding impact when the object  26  strikes the respective strip  16  is thus not transmitted or almost not transmitted at all to the shaft  24 . The selection of the spacing a between the strips  16  and the surface of the component  12  to be protected or the components  12  to be protected is determined in accordance with the typically occurring kinetic energies of the objects  26  and the rigidity of the strips  16 . 
       FIG. 2  shows a wheelset  30  having the wheelset shaft  14  and the two wheel discs  32 ,  34 . The wheelset shaft  14  is surrounded between the wheel discs  32 ,  34  by the stone impact protection arrangement  10 . This surrounds the strips  16  and two annular retention devices  36 ,  38  which each retain or support one of the end regions  18 ,  20  of the strips  16 . 
       FIG. 3  is a sectioned illustration through the vehicle component  12  which is to be protected and which is constructed as a wheelset shaft  14  and the stone impact protection arrangement  10  along the line of section III-III shown in  FIG. 2 . 
     The strips  16  are distributed peripherally with uniform radial spacing about the shaft  14  or the axis  24  thereof.  FIG. 3  shows a stone impact protection arrangement  10  having six plate-like strips  16 , but it is also possible to use fewer or more, for example, four or eight, strips  16 . The strips  16  further have a curvature. This curvature has, on the one hand, an advantageous influence on the flexural rigidity of the strips  16  and, on the other hand, a uniform spacing a is produced with respect to the covering face of the shaft  14 . 
     Finally,  FIG. 4  is a detailed drawing of one of the retention devices  36  of the stone impact protection arrangement  10  and shows the securing of this retention device  38  to the component  12  to be protected, that is to say, the wheelset shaft  14  (region IV of  FIG. 2 ). The other retention device  36  and the securing thereof are constructed accordingly. 
     The retention device  36 ,  38  for retaining/supporting the strips  16  is constructed in a resilient manner within the protection arrangement  10  so that free bending of the strips  16  is possible. The retention device  36 ,  38  has a base  40  which comprises two portions (more precisely, two half-shells), a profile-member  42  which also comprises two portions and a clip  44  which is constructed as a worm drive hose clip. The portions of the base  40  are produced from a resilient material, in particular a rubber-like material. The base  40  forms, together with the profile-member  42  which peripherally surrounds the base  40 , receiving members for the end regions  18 ,  20  of the strips  16 . The portions of the profile-member  42  may be produced either from metal materials or plastics materials. The connection of the retention device  36 ,  38  to the shaft  14  is carried out in each case by the clip  44  which is introduced into a shoulder of the profile-member  42  in order thereby to itself be protected against flying ballast.