Abstract:
A roller bearing cage has a cage element adapted for retaining the generally cylindrically shaped rollers and allowing the rollers to be rollable therein. The cage element includes a main portion having a plurality of pockets, an outward flange portion extending outwardly in a radial direction and an inward flange portion extending outwardly in the radial direction. The outward flange portion is formed on a side edge of the main portion and the inward flange is formed on an opposite side edge portion thereof. The main portion defines the smallest diameter of the bearing cage and is less than the roller pitch diameter.

Description:
RELATED APPLICATION DATA 
     This application claims the benefit of provisional application Ser. No. 61/820,239 filed May 7, 2013, the disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND 
     This disclosure pertains to a roller bearing with an outer race, an inner race, a plurality of rollers, and a pair of cages. The cages have an inward flange that is turned radially outward. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments. In the drawings: 
         FIG. 1  illustrates a perspective view of a bearing cage. 
         FIG. 2  illustrates a front view of the bearing cage of  FIG. 1 . 
         FIG. 3  illustrates a cross sectional view of the bearing cage of  FIG. 1 . 
         FIG. 4  illustrates an enlarged partial cross sectional view of a bearing with which the bearing cage of  FIG. 1  is assembled. 
         FIG. 5  illustrates a partial enlarged perspective view of an alternate embodiment of the bearing cage of  FIG. 1  with a roller shown in phantom. 
         FIG. 6  illustrates a partial enlarged perspective view of the bearing cage of  FIG. 5 . 
         FIG. 7A  illustrates a partial enlarged cross sectional view of a bearing cage of  FIG. 5 . 
         FIG. 7B  illustrates detail view  7 B of  FIG. 7A . 
         FIG. 8  illustrates a partial enlarged front view of an alternate embodiment of the bearing cage of  FIG. 1 . 
         FIG. 9  illustrates a partial enlarged perspective view of the bearing cage of  FIG. 8  with a roller shown in cross section. 
         FIG. 10  illustrates a partial enlarged perspective view of the bearing cage of  FIG. 8 . 
         FIG. 11  illustrates a partial enlarged perspective view of an alternate embodiment of the bearing cage of  FIG. 1  comprising a two piece assembly with a radial extension member attached to a locator to form an inward flange of the bearing cage. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an exemplary cage  20 , which may be used for a roller bearing, for instance, a self-aligning spherical roller bearing. The cage  20  may be formed by press-molding or stamping a metal plate or by injection-molding a synthetic resin. The cage has a main portion  22 , an outward flange portion  24  extending outwardly in the radial direction from a side of the main portion, and an inward flange portion  26  extending outwardly in the radial direction from the opposite side of the main portion. A plurality of pockets  28  is formed in the main portion  22 . Each pocket retains  28  a single generally cylindrically shaped roller  30  that is rollable therein. In  FIG. 1 , the main portion  22  disposed between the pockets  28  defines the inner diameter surface of the cage D3 and the inward flange  26  extends outward therefrom.  FIG. 4  shows additional detail with the inner most inner diameter of the cage indicated by D3. Thus the main portion  22  disposed between the pockets  28  defines bridges and the inward flange  26  extends radially outward therefrom. The inward flange  26  may be turned radially outward from the main portion  22  so that the main portion  22 , for instance, the bridges defined by the pockets, may define the innermost surface of the cage. As shown in  FIG. 3 , the main portion  22  may be conically shaped so the outward flange portion extends radially outward from a larger diameter side of the main portion and the inward flange portion extends radially outward from a small diameter side of the main portion, the smaller diameter portion being indicated by D3. The main portion may also be cylindrical rather than conical. By turning inward flange radially outward from the main portion, the overall rigidity of the cage may be maintained and provide the necessary clearance for use of the cage with an extended inner ring bearing style as explained below (see, e.g.,  FIG. 4 ). Preferably, the inward flange is turned at an angle 90° relative to the bridges. 
     To prevent the generally cylindrically shaped rollers from pulling out of the pockets in the radial direction, tongues or roller retainers may be provided adjacent the pockets. FIGS.  5 - 7 A, 7 B show an embodiment of the cage with the roller retainer  32 ′ formed on the outward flange  24 .  FIGS. 8-11  show an embodiment of the cage with the roller retainer  32  formed on the inward flange  26 . The roller retainers  32 , 32 ′ are preferably arranged in the center of each of the pockets  28  and engage recessed portions  34  in axial faces of the rollers  30 . The roller recess portions  34  may be circular in shape and located at the center of ends of the barrel-shaped rollers  30 . The recesses formed on the ends of the barrel-shaped rollers may also have an annular shape that is concentric with the barrel-shaped rollers. The roller retention feature or retainer  32 , 32 ′ formed on the inward flange may be machined, stamped, or coined. 
       FIG. 4  shows an exemplary extended inner ring bearing that may be used in connection with the above described bearing cage. The extended inner ring bearing  50  has an inner ring  51  with an extension portion  52  and an outer ring  54  supercircumjacent to the inner ring with the rollers  30  disposed therebetween. Because the inward flange  26  extends radially outward, the bearing cage  30  has radial clearance to allow its use in connection with the bearing  50  having with the inner ring extended portion  51 . Typically, the extended inner ring bearing inner ring extension portion  52  has an outer diameter surface with a diameter D1 that is greater in dimension than a diameter D2 of the outer diameter surface of the inner ring race. By forming the roller bearing cage inward flange  26  to extend radially outward, the inner most inner diameter D3 of the bearing cage  20  may be sized to allow it to be directed over the outer diameter surface D1 of the inner ring extension portion  52 . By outwardly turning the inward flange  26 , sufficiently material may be added to the inward flange (i.e., a relatively large outer diameter) to provide the bearing cage with overall rigidity and strength. The bridges of the main portion  22  may be formed in the cage at a diameter, for instance, diameter D3, that is less than the roller pitch D4. This eliminates the need to use other components such as guide rings and other bridges that separate the rollers at a diameter greater than the roller pitch. Moreover, the outwardly turned inner flange provides a location on the inner flange for the roller retainer  32 . When assembled in the bearing  50 , the outward flange portions  24  of a pair of cages  20  are arranged in an abutting arrangement. 
     As best shown in  FIGS. 5-11 , the bearing cage may be provided with guide surfaces  60  formed on outward flange  24  for guiding the rollers  30 . The guide surface may have cylindrically shaped contact surfaces that contact the axial ends of the rollers  30 , so the rollers can be guided with a full line of contact  62  ( FIG. 8 ) across the roller face whether the outer flange portion is in its designed position or skewed from loading or manufacturing inaccuracies. 
     The cylindrical shaped guide surfaces  60  may be formed on the outward flange portion  24  adjacent the pockets  28  on the inner side surfaces of the outward flange portion. The guide surfaces may be coined into a cylindrical shape (FIG.  5 , 6 ) or otherwise formed as a protrusion (FIGS.  7 A, 7 B). The guide surfaces  60  may be continuous along the pocket  28  ( FIG. 8 ) or may be intermittent (FIGS.  5 , 6 ). As best shown in  FIG. 8 , the guide surfaces  60  may be arranged in a straight line  62  across the pocket, thus defining a polygonal orientation of the guide surfaces on the outward flange. The number of sides to the polygon may correspond to the number of pockets and rollers of the bearing. As shown in  FIG. 2 , there are  18  pockets defining a  18  sided polygon. The guide surfaces are arranged to correspond to each side  70  of the polygon. 
     The guide surfaces  60  may be cylindrically shaped and abut against the axial end faces of the rollers substantially uniformly with line contact  62  across the axial end surface of the roller. The line contact improves the lubrication film that should exist between the roller face and guide surfaces. Additionally, providing full line contact across the roller face allows the generally cylindrically shaped rollers to be guided by the guide surfaces with minimal skew no matter if the flanged portion of the cage is stamped in position as designed or is leaning inward or outward. Further, the line of contact enables guiding of the rollers within greater manufacturing tolerances. For instance, a greater variation may be allowed in the stamping and the roller will contact the cylindrical guide surface at a different height on the roller but with full line contact. The cylindrical shape design enhances lubrication in between the roller and the cage guide surface regardless of the direction of rotation or manufacturing variance associated with the stamping. By forming the inward flange to extend radially outward, the inward flange may be formed with the roller retainer, and the outward flange may be provided with a more robust guide surface feature. 
       FIG. 11  show an alternate embodiment of the bearing cage with the inward flange  26 ′ comprising a two-piece assembly. Specifically, the inward flange  26 ′ comprises a ring-like, radially extending member  80  which is fitted onto a locator  82  at the inward most portion of the bridges  22 . For instance, it may not be desirable to form the roller retention feature on the inward flange due to manufacturing concerns. Accordingly, for manufacturability, an inward flange comprising a two-piece assembly enables the roller retainer  32  to be formed on the separate ring-like radially extending member  80  which may then be affixed to the locator  82  at the inward-most portion of the bridges. 
     In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.