Abstract:
A bearing assembly is provided having a roller bearing with an inner raceway fitted around the journal portion of an axle. An outer raceway combines with the inner raceway to receive roller elements. An improved lubricant seal arrangement is provided between the wear ring and the supporting outer raceway comprising a stator element, a rotor element and a flinger element.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to shaft journal bearings and, more particularly, to an improved bearing assembly seal arrangement for use in a railway freight car. 
         [0002]    Roller bearing assemblies incorporating two rows of tapered roller bearings preassembled into a self-contained, pre-lubricated package for assembly onto journals at the ends of axles or shafts are known. Such bearing assemblies are used as rail car bearings assembled onto journals at the ends of the axles. Bearings of this type typically employ two rows of tapered roller bearings fitted one into each end of a common bearing cup with their respective bearing cones having an inner diameter dimensioned to provide an interference fit with the shaft journal and with a cylindrical sleeve or spacer positioned between the cones providing accurate spacing and proper lateral clearance on the journal. Seals mounted within each end of the bearing cup provide sealing contact with wear rings bearing against the outer ends or back face of the respective bearing cones at each end of the assembly. Such seals are shown in U.S. Pat. Nos. 5,975,533, 7,607,836, and 7,534,047. 
         [0003]    In a typical rail car installation, the axle journal is machined with a fillet at the inboard end. A backing ring having a surface complementary to the contour of the fillet and an abutment surface for engaging the inboard end of an inner wear ring accurately position the bearing assembly on the journal. An end cap mounted on the end of the axle by bolts threaded into bores in the end of the axle engages the outboard wear ring and clamps the entire assembly on the end of the axle. The wear rings typically have an inner diameter dimensioned to provide interference fit with the journal over at least a portion of their length so that the entire assembly is pressed as a unit onto the end of the journal shaft portion of the axle. 
       SUMMARY OF THE INVENTION 
       [0004]    The bearing assembly of the present invention is a roller bearing that includes an inner race or cone fitted around the journal portion of the axle or shaft. The inner race includes an outwardly directed raceway. An outer race or cup has an inwardly directed raceway. Roller elements are located between and contacting the inner and outer raceways. 
         [0005]    A backing ring has a contoured surface complementary to and engaging the contoured surface of a fillet formed on the shaft. The fillet leads from the journal to the shoulder of the shaft. The contoured surfaces cooperate to fix the backing ring against axial movement along the shaft. 
         [0006]    The bearing assembly includes a seal assembly that provides a barrier for lubricant to be retained within the seal assembly and for contaminants to be kept out. The seal assembly includes a stator adjacent a seal section itself and a rotor affixed to a wear ring. A flinger is provided to interact with the rotor and the stator to provide an improved seal. The inter-related relationship between the seal section, stator rotor and flinger act to retain the lubricant within the seal assembly and to keep contaminants out. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    In the drawings, 
           [0008]      FIG. 1  is a sectional view of a shaft journal having mounted thereon a tapered roller bearing assembly in accordance with an embodiment of the present invention; 
           [0009]      FIG. 2  is a detailed partial view in cross section of a tapered roller bearing seal assembly in accordance with a first embodiment of the present invention; 
           [0010]      FIG. 3  is a detailed view in partial cross section of a tapered roller bearing assembly in accordance with a second embodiment of a present invention, and 
           [0011]      FIG. 4  is a detailed view in partial cross section of a tapered roller bearing assembly in accordance with a third embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]    Referring now to  FIG. 1  of the drawings, a bearing assembly indicated generally by the reference numeral  10  on  FIG. 1  is shown mounted on a journal  12  on the free, cantilevered end of a shaft or axle  14 , typically a rail car axle. Journal  12  is machined to very close tolerances and terminates at its inner end in a contoured fillet  22  leading to a cylindrical shoulder  18  of axle  14 . At the free end of the axle, journal portion  12  terminates in a slightly conical or tapered guide portion  24  dimensioned to facilitate installation of the bearing assembly onto the journal. A plurality of threaded bores  26  are formed in the end of axle  14  for receiving threaded cap screws, or bolts  28  for mounting a bearing retaining cap  30  on the end of the shaft to clamp the bearing in position as described more fully herein below. 
         [0013]    The bearing assembly  10  is preassembled before being mounted and clamped on journal  12  by retaining cap  30  and bolts  28 . The bearing assembly includes a unitary bearing cup or outer raceway  32  having a pair of inner facing raceways  34 , 36  formed one adjacent each end thereof which cooperate with a pair of bearing cones  38 , 40 , having outer facing raceways respectively, to support the two rows of tapered rollers  42 , 44 , respectively there between. A center spacer  46  is positioned between cones  38 , 40  to maintain the cones in accurately spaced position relative to one another allowing for proper bearing lateral clearance. 
         [0014]    The bearing cup  32  is provided with cylindrical counterbores  17 , 19  at its opposite ends outward of the inner facing raceways  34 , 36  and a pair of seal sections  52 , 58  are pressed one into each of the cylindrical counterbores  17 , 19  in cup  32 . Each seal section  52 , 58  may include resilient sealing elements  57  which rub upon and form a seal with surfaces  37 , 61  of a pair of seal wear rings  60 , 62  having an inwardly directed end in engagement with the outwardly directed ends of bearing cones  38 , 40  respectively. Seal section  58  is similar to seal section  52  and will not be described in detail. The other end of wear ring  60  is received in a cylindrical counterbore  64  in the axially outwardly directed end of an annular backing ring  66  which, in turn, has a counterbore  68  at its other end which is dimensioned to be received in interference and non-interference relation on the cylindrical shoulder  18  of shaft  14 . The counterbore  64  and the outer diameter of wear ring  60  are also dimensioned to provide an interference fit so that wear ring  60  is pressed into the backing ring  66  which is accurately machined to provide a contoured inner surface  70  complementary to and engaging the contour of fillet  22  when the bearing is mounted on the shaft. The outwardly directed end of wear ring  62  bears against a counterbore  31  in a retaining cap  30 . 
         [0015]    Referring now to  FIG. 2 , a detailed view of seal assembly portion of bearing assembly  10  is provided. Seal section  52  is seen to comprise a generally cylindrical piece, having a larger diameter first end section  48  pressed or fit into a complementary counterbore  17  in a cup  32 . Seal section  52  includes an intermediate section  27  normal to first end section  48  and a main intermediate cylindrical section  53  that extends parallel to end section  48 , wherein main intermediate cylindrical section  53  has a smaller diameter than end section  48 . 
         [0016]    Second end section  55  of seal section  52  extends from main intermediate section  53  at a normal angle thereto. Resilient sealing element  58  is fitted onto second end section  55 . Resilient sealing element  58  is comprised of a rubber or elastomer compound, such as nitrile rubber compound. Resilient sealing element  58  includes a main section that includes an opening to receive second end  55  of seal section  52 . Resilient sealing element  58  also includes base ribs  69 . 
         [0017]    Stator  47  is generally cylindrical piece, having a base section  29  and a radially outer section  49 . An outer surface of outer section  49  is affixed by welding, gluing, dimpling, interference fit, or other appropriate method to an inner surface of main cylindrical section  53  of seal assembly  52 . Stator  47  also includes intermediate section  51  that extends from base section  29  parallel to outer section  49 . Radially inner section  88  of stator  47  extends at a normal angle from base section  29 . Stator  47  is usually a unitary structure comprised of a structural plastic or steel. 
         [0018]    Rotor  81  is seen to be a generally cylindrical structure comprised of a base section  86  and a radially outer section  82  extending therefrom and generally normal thereto. Radially intermediate section  83  extends from base section  86  and is generally normal thereto. Radially inner section  84  of rotor  81  extends from base section  86  and is generally normal thereto. Radially inner section  84  of rotor  81  has a radially inner surface  95  which is fitted against radially outer surface  56  of flinger section  65 . Rotor  81  is usually a unitary structure comprised of a structural plastic or steel. 
         [0019]    Flinger section  65  comprises a generally cylindrical structure having a base section  57 , an intermediate section  59  extending from and normal to base section  57 , and end section  61  extending from and normal to intermediate section  59 . Flinger section  65  is usually a unitary structure comprised of a structural plastic or steel. 
         [0020]    Flinger section  65  base section  57  is seen to have an end  67  that extends to or nearly to inner sidewall  94  of cone  38 . Radially inner section  84  of rotor  81  is seen to abut outer surface  56  of flinger section  65 . Radially inner section  84  of rotor  81  is also seen to include a protruding snap device  87  that is received in a complementary opening on outer surface  56  of flinger section  65 . It can be seen that generally cylindrical flinger section  65  can be snap fit assembled into bearing assembly  10 . Inner surface  79  of flinger section  65  is seen to abut outer surface  37  of wear ring  60 . 
         [0021]    Referring now to  FIG. 3 , a second embodiment of the roller bearing seal assembly of the present invention is shown generally at  110 . 
         [0000]    Seal section  152  is seen to comprise a generally circular piece, having a larger diameter first end section  148  pressed or fit into a complementary counterbore  117  in a cup  132 . Seal section  152  includes an intermediate section at normal to first end section  148  an a main intermediate cylindrical section  153  that extends parallel to end section  148 , wherein main intermediate cylindrical section  153  has a smaller diameter than end section  148 . Second end section  155  of seal section  152  extends from main intermediate section  153  at a normal angle thereto. 
         [0022]    Stator  147  is generally cylindrical piece, having a base section  129  having a radially outer section  149 . The outer surface of outer section  149  is affixed by welding, gluing, dimpling, interference fit, or other appropriate method to an inner surface of main cylindrical section  153  of seal section  152 . Stator  147  also includes intermediate section  151  that extends from base section  129  parallel to outer section  149 . Radially inner section  188  extends at a normal angle from base section  129 . Stator  147  is usually a unitary structure comprised of a structural plastic or steel. 
         [0023]    Rotor  181  is seen to be a generally cylindrical structure comprised of a base section  186  and a radially outer section  182  extending therefrom and generally normal thereto. Radially intermediate section  183  extends from base section  186  and is generally normal thereto. Inner section  184  of rotor  181  extends from base section  186  and is generally normal thereto. Inner section  184  of rotor  181  has an outer surface  195  which is fitted against radially outer surface  137  of wear ring  160 . Rotor  181  is usually a unitary structure comprised of a structural plastic or steel. 
         [0024]    Flinger section  165  comprises a generally cylindrical structure having a base section  157 , an intermediate section  159  extending from and normal to base section  157 , and end section  161  extending from and normal to intermediate section  159 . Flinger section  165  is usually a unitary structure comprised of a structural plastic or steel. 
         [0025]    Flinger section  165  base section  155  is seen to have an end  167  that extends to or nearly to inner sidewall  185  of rotor  181 . Radially inner section  184  of rotor  181  is seen to abut outer surface  155  of flinger section  165 . End  167  of flinger section  165  seen to include a protruding snap device  187  that is received in a complementary opening on inner surface  158  of radially inner section  184  of rotor  181 . It can be seen that generally cylindrical flinger section  165  can be snap fit assembled into bearing assembly  110 . 
         [0026]    Referring now to  FIG. 4 , a third embodiment of the roller bearing seal assembly of the present invention is shown generally at  210 . 
         [0027]    Seal section  252  is seen to comprise a generally circular piece, having a larger diameter first end section  248  pressed or fit into a complementary counterbore  217  in a cup  232 . Seal section  252  includes an intermediate section  227  normal to first end section  248 , and a main intermediate cylindrical section  253  that extends parallel to end section  248 , wherein main intermediate cylindrical section  253  has a smaller diameter than end section  248 . Second end section  255  of seal section  252  extends from main intermediate section  253  at a normal angle thereto. 
         [0028]    Stator  247  is generally cylindrical piece, having a base section  229  and a radially inner section  249 . An outer surface of a portion  249 A of radially outer section  249  is affixed by welding, gluing, dimpling, interference fit, or other appropriate method to an inner surface of main cylindrical section  253  of seal assembly  252 . Stator  247  also includes intermediate section  251  that extends from base section  229  parallel to radially outer section  249 . Radially inner section  288  of stator  247  extends at a normal angle from base section  229 . Stator  247  is usually a unitary structure comprised of a structural plastic or steel. 
         [0029]    Rotor  281  is seen to be a generally cylindrical structure comprised of a base section  286  and a radially outer section  282  having extending therefrom and generally normal thereto. Radially intermediate section  283  extends from base section  286  and is generally normal thereto. Radially inner section  284  of rotor  281  extends from base section  286  and is generally normal thereto. Radially inner section  284  of rotor  281  has a radially inner surface  295  which is fitted against radially outer surface  255  of flinger section  265 . 
         [0030]    Flinger section  265  comprises a generally cylindrical structure having a base section  257 , an intermediate section  259  extending from and normal to base section  257 , and end section  261  extending from and normal to intermediate section  259 . Flinger section  265  is usually a unitary structure comprised of a structural plastic or steel. 
         [0031]    Flinger section  265  base section  255  is seen to have an end  267  that extends to or nearly to inner sidewall  294  of cone  238 . Radially inner section  284  of rotor  281  is seen to abut outer surface  255  of flinger section  265 . Radially inner section  284  of rotor  281  is also seen to include a protruding snap device  287  that is received in a complementary elongated opening  297  in outer surface  255  of flinger section  265 . It can be seen that generally cylindrical flinger section  265  can be snap fit assembled into bearing assembly  210 . Inner surface  279  of flinger section  265  is seen to abut outer surface  237  of wear ring  260 . Elongated opening  297  allows flinger section  265  and rotor  281  to slide relative to one another to allow for variations of lateral clearance in both new and reconditioned bearings. An annular ring  286  may be provided on flinger section  265 . Annular ring  286  prevents flinger  265  from contacting seal section  252  along an area versus a line contact. It also spaces flinger  265  properly to seal section  252 .