Abstract:
The present invention provides for a grease baffle that may be installed and removed independently of an outer race of a bearing assembly, thus reducing or eliminating damage to the grease baffle during maintenance actions. Further, the present invention eliminates the potential for damage to the bearing support body for maintenance actions requiring removal of the grease baffle but not removal of the outer race. Moreover, the present invention results in reduced maintenance time and reduced maintenance costs. The grease baffle may be retained in the support body by a retaining ring or a resilient sealing member, and may be preloaded against a retaining surface.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/502,895 filed Jun. 30, 2011, which is hereby incorporated herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates to bearing assemblies, and more particularly to a grease baffle seal for use in a bearing assembly wherein a grease baffle is sealed at its outer diameter by a resilient sealing member providing a preload against a retaining surface. 
       BACKGROUND 
       [0003]    Bearing assemblies generally include balls or cylinders (generically, “bearing elements”) which are positioned between an inner bearing race and an outer bearing race. Bearing assemblies may be either inner or outer rotators depending on whether the rim or shaft rotates. For mechanisms using a rotating shaft, the inner bearing race rotates with the shaft. For mechanisms using a rotating rim, the outer bearing race rotates with the rim. The bearing elements are preferably evenly spaced within the inner bearing race and outer bearing race. The bearing elements may be held in this evenly spaced position by, for example, teeth of a roller cage. 
         [0004]    Bearing lubricant fluid is used in bearing assemblies to encourage free movement of the bearing elements, inner bearing race, and outer bearing race. During operation, however, the lubricant tends to migrate and eventually may escape the bearing assembly. The lubricant that migrates and escapes the bearing assembly can then enter the rest of the mechanism utilizing the bearing assembly, and even exit the mechanism completely. 
         [0005]    Known grease baffles may be installed between the outer bearing race and the outer support body (or “register”) holding the outer race and any maintenance or assembly action that requires removal of the outer bearing race or grease baffle requires removing both the race and grease baffle. This operation results in a damaged or destroyed grease baffle and damage to the support body. 
       SUMMARY OF INVENTION 
       [0006]    The present invention provides for a grease baffle that may be installed and removed independently of the outer race thus reducing or eliminating damage to the grease baffle during maintenance actions. Further, the present invention eliminates the potential for damage to the bearing support body for maintenance actions requiring removal of the grease baffle but not removal of the outer race. Moreover, the present invention results in reduced maintenance time and reduced maintenance costs. 
         [0007]    One aspect of the present invention provides for a bearing assembly including an outer race, an inner race, a plurality of bearing elements disposed between the inner and outer races for allowing relative rotational movement between the inner and outer race, an annular support body rigidly supporting the outer race and extending therefrom in an axial direction, an annular grease baffle disposed axially proximal to the outer race and inner race for preventing migration of grease away from the plurality of bearing elements, and an annular resilient sealing member interposed between the baffle and an abutment surface, wherein the sealing member axially biases an outer periphery of the baffle against the retaining surface for preventing movement of the baffle with respect to the support body. The annular grease baffle has a portion disposed against a retaining surface 
         [0008]    The resilient sealing member may be disposed in an annular groove in the support body. 
         [0009]    The bearing assembly may include an annular retaining element having the retaining surface, the retaining element being disposed in an annular retaining element groove of the support body. 
         [0010]    The retaining surface may be an axial surface of the outer race. 
         [0011]    The annular resilient sealing member may be disposed between the grease baffle and an axial ledge of the support body. 
         [0012]    The annular grease baffle may be removable from the support body without removal of the outer race. 
         [0013]    The bearing assembly may be in combination with an aircraft wheel. The combination may include wheel halves, each half including a bearing assembly, a hub half forming the support body and the hub halves collectively defining an interior space, and a bearing seal for sealing the bearing assembly from an exterior side of the wheel half. The grease baffles may be disposed on an interior side of the wheel half for preventing grease from migrating out of the bearing assembly into the interior space. 
         [0014]    The grease baffles may be removable, independent of the outer races, from the hub halves forming the support bodies by removal of respective retaining rings or resilient sealing members. 
         [0015]    Another aspect of the present invention provides for a method for preventing lubricant from migrating out of a bearing assembly having an outer race, an inner race, a plurality of bearing elements disposed between the inner and outer races, an annular support body rigidly supporting the outer race and extending therefrom in an axial direction, an annular grease baffle disposed axially proximal to the outer race and inner race and having a portion disposed against a retaining surface, and an annular resilient sealing member interposed between the baffle and an abutment surface. The method may include the steps of preloading a grease baffle against a retaining surface with the annular resilient sealing member, and sealing an interface between the grease baffle and a support body with the annular resilient sealing member. 
         [0016]    Another aspect of the present invention provides for a method for removing a grease baffle from a bearing assembly having a an outer race, an inner race, a plurality of bearing elements disposed between the inner and outer races, an annular support body rigidly supporting the outer race and extending therefrom in an axial direction, an annular grease baffle disposed axially proximal to the outer race and inner race and having a portion disposed against a retaining surface, and an annular resilient sealing member interposed between the baffle and an abutment surface. The method may include the steps of removing an annular resilient sealing member, and removing the grease baffle without removing and without damaging an outer race. 
         [0017]    The method may also include the step of removing a retaining element from a retaining element groove in a support body. 
         [0018]    The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a sectioned perspective view of a bearing assembly in accordance with the present invention including a c-shaped grease baffle; 
           [0020]      FIG. 2  is a sectional view of an aircraft wheel assembly including a bearing assembly with a grease baffle; 
           [0021]      FIG. 3  is a partial sectional view of an aircraft wheel assembly including a bearing assembly with a c-shaped grease baffle; 
           [0022]      FIG. 4  is a partial sectional view of a bearing assembly in accordance with the present invention including an ogee-shaped grease baffle. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    A bearing assembly in accordance with present invention may be used in a number of applications, but, for ease of explanation and comprehension, will be described herein in reference to a tapered roller bearing assembly for use in an aircraft wheel. The invention is equally applicable in other settings and to other bearing assemblies, for example ball bearing assemblies, as long as the bearing type involves radial differential motion with inner and outer interfaces separated by a gap or across the width of the bearing assembly. 
         [0024]      FIG. 1  is a perspective view of a bearing assembly  100  that may be used in accordance with aspects of the present invention. The bearing assembly  100  may include an inner race  102  and an outer race  104 . Positioned between the inner race  102  and the outer race  104  are a plurality of bearing elements  106  held in spaced alignment by a roller cage  108 . 
         [0025]    The bearing elements may be guided by flanges  109 ,  111  on the inner race  102  that prevents the bearing elements  106  from sliding out of the assembly  100 . 
         [0026]    The inner race  102  and outer race  104  may be segments of cones and the bearing elements  106  may also be made with a taper so that the conical surfaces of the races  102 ,  104  and the axes of the bearing elements  106  would, if projected, meet at a common point on the main axis of the bearing assembly  100 . 
         [0027]    This conical geometry may be used in certain applications so as to provide a relatively large contact surface between the bearing elements  106  and the races  102 ,  104 , which permits greater loads to be carried than with spherical (ball) bearings, while still preventing differential scrubbing between the surfaces. 
         [0028]    The half angle of these cones may be selected so as to provide appropriate strength for sustaining axial loads applied to the bearing assembly  100 . 
         [0029]    Further, the illustrated tapered roller bearings may be used in back-to-back pairs, as shown in  FIGS. 2 and 3  so that axial forces can be supported in either direction. 
         [0030]    In use, as shown in  FIGS. 2 and 3 , two bearing assemblies may be disposed in a wheel assembly  200  in a back-to-back or inverted arrangement. In the wheel assembly  200 , the axle  202  may remain fixed with respect to the vehicle the wheel is attached to, while the rim  204  rotates about the axle  202 . In this configuration, the inner race  102  is rigidly affixed to the axle  202  and does not rotate. The outer race  104  is rigidly affixed to a support body  110  and both rotate with the rim  204  of the wheel. 
         [0031]    This rotation causes a centrifugal force which tends to fling the bearing lubricant to the outer diameter of the outer race  104  and out of the bearing assembly. Because there are situations in which a bearing assembly is not exposed to contaminants, a bearing seal may not be needed. In these cases, for example, where the overriding concern is maintenance of lubrication, a baffle may be simpler and cheaper and may cause less friction when in use. As shown in  FIGS. 2 and 3 , for example, bearing assemblies in an aircraft wheel may have their axially outer sides sealed with a bearing seal to keep out contaminants, while their axially inner sides may include a simpler baffle to retain lubricant. 
         [0032]    As such, in order to keep the bearing lubricant from migrating out of the bearing assembly  100 , the assembly of  FIGS. 2 and 3  includes an annular grease baffle  120  axially spaced from the outer race  104  and inner race  102  which acts as a barrier to prevent lubricant from escaping. The grease baffle  120  may have any appropriate cross section so as to contain the lubricant. 
         [0033]    In one embodiment, for example as shown in  FIG. 3 , the grease baffle  120  may be generally “c” shaped and positioned so that the concave side of the grease baffle  120  faces the plurality of bearing elements  106 . In some applications this shape may help redirect the bearing lubricant back towards the plurality of bearing elements  106 . During rest, this shape may also act to provide a reservoir for lubricant that drains from around the bearing elements due to gravity. Typically, any oozing of the lubricant due to gravity or flight (or other) loads is remedied by rolling on take-off and landing, or other use of the bearing assembly. 
         [0034]    As shown in  FIG. 3 , the grease baffle  120  may have a portion, in this embodiment an end of the ‘c’, which is disposed against a retaining surface. This retaining surface may be, for example, a sidewall  105  of the outer race  104 , as shown in  FIG. 3 . Alternatively, the retaining surface may be an axial ledge in the support body  110 , or a retaining ring disposed in an annular groove of the support body  110  (not shown). The inner diameter of the grease baffle  120  may be adjacent to the inner race  102 , or may be spaced therefrom. 
         [0035]    In another embodiment, for example, in  FIG. 4 , the grease baffle  120 ′ may be ogee shaped. Preferably, an ogee shaped grease baffle  120 ′ is disposed so that the inner diameter of the grease baffle  120 ′ is proximal the outer race  104  and inner race  102  as compared to the outer diameter. In other words, the ogee shape curves axially and radially inwardly, as shown in  FIG. 4 . 
         [0036]    A radially outer portion of grease baffle  120 ′ may be disposed against a retaining ring  125  or a ledge (not shown) in the support body  110 . The retaining ring  125  may be disposed in an annular groove  127  of the support body  110 , and may be made of any suitable material for retaining the baffle  120 ′. The radially inner side of the baffle  120 ′ may be adjacent to or spaced from the inner race  102 . 
         [0037]    Other shapes for the grease baffle are possible but are omitted for brevity. 
         [0038]    Regardless of the shape, the grease baffle  120 ,  120 ′ may be retained in the support body  110  by an annular resilient sealing member  130 , a retaining ring  125 , or a combination thereof. Further, the resilient sealing member  130  provides a positive retention force (preload energizer) by pressing the grease baffle  120 ,  120 ′ against an opposing retaining surface thereby preventing rattling during use and helping to seal the baffle against the retaining surface. In addition to retaining and preloading the grease baffle  120 ,  120 ′, the resilient sealing member  130  may also seal the interface between the grease baffle  120 ,  120 ′ and an abutment surface (e.g., portion of the support body  110  or the outer race  104 ) to prevent leakage of lubricant at the site of the resilient sealing member  130 . In a preferred embodiment, the resilient sealing member is elastomeric. In another preferred embodiment, the resilient sealing member is an O-ring. The resilient sealing member may be received in an annular resilient sealing member groove  135  in the inside surface of the support body  110 , or may be disposed against the inside surface of the support body  110  and between the grease baffle  120 ,  120 ′ and either a counter bore  115  of the support body or the outer race  104  itself. 
         [0039]    The retaining surface may be, for example, an axial ledge  150  of the support body  110 . Alternatively, the retaining surface may be an axial surface  151  of the outer race  104 . Alternatively, the retaining surface may be the removable retaining ring  125  disposed in an annular groove  127  of the support body  110 . Further, the retaining surface may be a combination of one or more of these elements. 
         [0040]    Because the grease baffle  120 ,  120 ′ is not necessarily providing a seal against contaminants, a relatively large gap between the baffle and the races  102 ,  104  may exist. 
         [0041]    The grease baffle  120 ,  120 ′ and resilient sealing member  130  may be installed and removed using standard O-ring/retaining ring installation and removal tools (for example, picks and the like). The grease baffle  120 ,  120 ′ may be installed and removed independently of the outer race  104 , thereby preventing damage and simplifying maintenance by reducing maintenance costs and downtime. 
         [0042]    Referring back to  FIG. 2 , the bearing assembly  100  may be used in the wheel assembly  200 . As shown, the wheel assembly may include two wheel halves  210 ,  211 . Each wheel half may include a hub portion  220 ,  221 . The rim  204  may be made of two rim portions  230 ,  231  respectively connected to the hub portions  220 ,  221  by web portions  240 ,  241 . The hub portions  220 ,  221 , and optionally the web portions  240 ,  241 , may define an interior space  250 . The grease baffles may be disposed on an interior side of the wheel halves and be used to prevent lubricant from migrating out of the bearing assemblies and into this interior space  250 . The grease seals  260  may be used to seal the bearing assemblies from an exterior side of the wheel halves. In this configuration, the wheel halves  210 ,  211  rotate around the fixed axle  202 . The wheel halves may be connected together by a plurality of fasteners  270  (e.g., bolts) and may be disassembled by removal of the fasteners in order to access the interior side of the wheel halves. Such access allows easy removal of the grease baffles without removal of the outer race from the bearing assembly  100 . 
         [0043]    Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.