Abstract:
A bearing and housing assembly for irregular shaped housings including a circular extension, retention and distortion relief features that can mitigate shape distortion of bearings.

Description:
TECHNICAL FIELD 
     Example aspects described herein relate to bearing and housing assemblies, particularly of bearings in irregular shaped housing designs. 
     BACKGROUND 
     Bearing assemblies are typically circular in shape, and generally comprise rolling elements sandwiched between raceways in bearing rings. Rolling elements take many forms, including spherical balls, rollers or various other configurations, such as cone-shaped tapered rollers or barrel-shaped spherical rollers. In order to provide proper anti-friction operation and intended function, including maintaining rolling contact and supporting a specified load, bearings require that some level of concentricity and bearing race circularity be maintained from the outer radial surface of the bearing assembly to the inner radial surface of the bearing assembly. In addition, a clearance equal to or above 0 is typically needed in order that the load zone of the bearing is not spread to the entire circumference of the bearing. Where concentricity and circularity is not maintained, or where there are multiple load zones on a single bearing owing to improper clearance or bearing ring distortion, increased fatigue, noise and vibration, and premature failure of the assembly may result. 
     In designing a bearing and housing assembly, bearing retention in the housing, bearing clearance, concentricity and, where dissimilar materials are used, operating temperature and variations in coefficients of thermal expansion must be considered. In particular, where the housing is of an irregular shape, such as a triangle or a general non-defined geometry, special attention must be provided to distortion of the typically circular bearing shape. U.S. Pat. No. 3,512,855 “Low Stress Bearing” discloses stress relief features in the bearing outer ring and various concentric assemblies in order to reduce stress in the bearing raceway. A solution to address bearing retention and shape distortion in non-concentric housings is needed. 
     SUMMARY OF THE INVENTION 
     A new design for a bearing and housing assembly, in particular, a bearing in an irregular shaped housing is disclosed. In one example embodiment of the invention, the assembly comprises a non-concentric housing, such as a triangular shaped housing, including a circular extension, retention lip and relief feature to prevent distortion of a bearing assembled therein. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above mentioned and other features and advantages of the embodiments described herein, and the manner of attaining them, will become apparent and be better understood by reference to the following description of at least one example embodiment in conjunction with the accompanying drawings. A brief description of those drawings now follows. 
         FIG. 1  is a perspective view of a housing according to one example embodiment herein. 
         FIG. 2  is a front view of the housing of  FIG. 1 . 
         FIG. 3  is a cross sectional view of the housing, taken along line A-A of  FIG. 2 . 
         FIG. 4  is a diagrammatic view of a bearing and housing assembly according to one example embodiment herein. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Identically labeled elements appearing in different ones of the figures refer to the same elements but may not be referenced in the description for all figures. The exemplification set out herein illustrates at least one embodiment, in at least one form, and such exemplification is not to be construed as limiting the scope of the claims in any manner. 
       FIG. 1  is a perspective view of housing  10  according to one example embodiment of the invention. In this perspective view, housing circular extension  11 , retention lip  12 , distortion relief feature  14 , and end stop  16  are shown. Housing  10  is shown as a triangular structure in this embodiment; however any irregular or non-concentric housing can be used. Circular extension  11  is a circular or round, axially outward extending portion of housing  10 , coincident with an outer diameter of a bore extending at least partially through said housing  10 . Although extension  11  is shown as integrally formed with housing  10 , it is contemplated that extension  11  can be separately formed and later assembled onto or with housing  10 . 
       FIG. 2  is a front view of housing  10  of  FIG. 1 . Retention lip  12  is shown.  FIG. 3  is a cross sectional view of housing  10 , taken along line A-A of  FIG. 2 . Retention lip  12  of housing  10  extends towards radial center R of circular extension  11 , and as shown in  FIG. 4 , provides a radial contact surface  13  to contact radial outer surface  19  of a bearing  18  of a bearing and housing assembly. As retention lip  12  extends from circular extension  11 , the distortion that can be caused by irregular shaped housing  10  is mitigated or substantially reduced. Circular housing extension  11  can extend from housing  10  a minimal distance X in keeping the circularity of extension  11 . By isolating contact surface  19  of bearing  18  from the irregular shape of housing  10 , the distorting effect of irregular shaped housing  10  on bearing  18  can be mitigated or substantially reduced. Contact surface  13  and radial outer surface  19  can be designed such that bearing  18  is retained in a bore in housing  10  during transport and assembly into surrounding structures (not shown), (e.g. the surfaces  13  and  19  can be press fit, interlocked or otherwise stably engaged). The level of press fit between radial contact surface  13  of retention lip  12  and radial outer surface  19  of bearing  18  will depend on the specific application needs of any particular system. Radial inner surface  20  of bearing  18  can be pressed onto a shaft or other similar structure (not shown). As further shown in  FIG. 4 , end stop  16  can be provided in housing  10  in order to provide a press depth surface and axial support for bearing  18  into housing  10 . Although shown as a fully extending flange along the entire inner circumference of housing  10 , end stop  16  may take various forms, and in other embodiments may extend along only part of that circumference. As further shown, irregular shaped housing  10  has no direct radial contact with bearing  18 , the radial contact isolated from irregular shaped housing  10  by circular extension  11  and retention lip  12 . 
     As shown in  FIG. 4 , retention lip  12  extends toward bearing  18  from circular extension  11 , and is designed such that the entire lip lies outside the imaginary vertical plane corresponding to line C and thus outside the running area, defined as the area lying between planes C and D. Vertical planes C and D are, in turn, vertically tangential to opposing end faces at points E and F, respectively, of at least one of rolling elements  22  (only one is shown, but, more than one can be included). Retention lip  12  may also be duplicated on the opposite end of bearing  18  from line C, and would be designed to lie outside the imaginary plane corresponding to line D, although this is not shown for convenience. Conventionally, shape distortion of bearing  18  can have a most significant detrimental impact in the running area, defined as the area lying between planes C and D, of rolling element  22  between outer ring  23  and inner ring  24 . However, in accordance with an example aspect of the invention, by extending circular extension  11  axially outward of irregular shaped housing  10 , and placing retention lip  12  outside that running area, and including distortion relief feature  14  at least over that running area, the distortion caused by pressing a circular bearing into an irregular shaped housing is mitigated or substantially avoided. In effect, circular extension  11  is isolating bearing  18  from radial contact with irregular shaped housing  10 , thus maintaining general circularity of bearing  18  assembled into a bore of housing  10 . 
     In the foregoing description, example embodiments are described. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto, without departing from the broader spirit and scope of the present invention. 
     In addition, it should be understood that the figures illustrated in the attachments, which highlight the functionality and advantages of the example embodiments, are presented for example purposes only. The architecture or construction of example embodiments described herein is sufficiently flexible and configurable, such that it may be utilized (and navigated) in ways other than that shown in the accompanying figures. 
     Although example embodiments have been described herein, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than as specifically described. Thus, the present example embodiments should be considered in all respects as illustrative and not restrictive. 
     LIST OF REFERENCE SYMBOLS 
     
         
           10  Housing 
           11  Housing Circular Extension 
           12  Retention Lip 
           13  Retention Lip Radial Contact Surface 
           14  Distortion Relief Feature 
           16  Housing End Stop 
           18  Bearing 
           19  Bearing Radial Outer Surface 
           20  Bearing Radial Inner Surface 
           22  Rolling Element 
           23  Bearing Outer Ring 
           24  Bearing Inner Ring 
         C Rolling Element Tangential Plane 
         D Rolling Element Tangential Plane 
         E End Face or Point 
         F End Face or Point 
         X Circular Extension Length from Housing