Abstract:
A including: an inner race; an outer race arranged to rotate freely relative to the inner race and including a circumferentially disposed channel forming a portion of a first radially outermost surface of the outer race; a cage located in the channel and comprising a first plurality of apertures; and a plurality of rolling elements, each rolling element in the plurality of rolling elements disposed in a respective aperture included in the first plurality of apertures.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62/072,166, filed Oct. 29, 2014, which application is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates generally to a ball bearing, and, more specifically, to a ball bearing with a cage and rolling element configuration on the outer race to prevent seizing of the bearing while in operation. 
       BACKGROUND 
       [0003]    Ball bearings have been used for many different mechanical applications. A ball bearing is often used when a rotatable shaft must be mounted within a housing. The insertion of a ball bearing reduces the friction that would occur between the shaft and the housing if the shaft were to ride directly on the surface of the housing. This would lead to grinding and eventual failure of the shaft or housing. Since a ball in a ball bearing is free to rotate between an inner race and an outer race, little to no friction occurs between the shaft and housing. 
         [0004]    As the shaft rotates, heat can build up within the bearing and shaft causing axial expansion of the shaft. If the bearing is fixedly mounted within the housing and cannot be axially displaced, the bearing can seize and bind to the housing causing bearing damage due to induced axial load. This seizing of the bearing can be detrimental to a machine which is operating at high speed and high heat since the shaft will no longer be rotating with little to no friction. 
         [0005]    A solution to avoid seizing of a ball bearing is to insert a linear bearing cartridge with the ball bearing. This solution will solve the problem of a bearing seizing with the housing since the linear bearing will enable axial expansion of the rotating shaft. A problem with using a linear bearing cartridge, though, is that a linear bearing cartridge requires a large amount of space to be installed properly with a ball bearing. Additionally, a linear bearing is an expensive component since there are more required components for the arrangement to work properly. 
         [0006]    Thus, there has been a long-felt need for a ball bearing that can rotate at high speed and has integrated components within the bearing in order to enable for axial expansion of a rotating shaft to prevent seizing of the bearing with the housing. 
       SUMMARY 
       [0007]    According to aspects illustrated herein, there is provided a bearing arranged to reduce friction between a housing and a rotating shaft, including: an inner race; an outer race arranged to rotate freely relative to the inner race and including a circumferentially disposed channel forming a portion of a first radially outermost surface of the outer race; a cage located in the channel and comprising a first plurality of apertures; and a plurality of rolling elements, each rolling element in the plurality of rolling elements disposed in a respective aperture included in the first plurality of apertures. 
         [0008]    According to aspects illustrated herein, there is provided a bearing arranged to reduce friction between a housing and a rotating shaft including: an inner race; an outer race arranged to rotate freely relative to the inner race and including a circumferentially disposed channel forming a portion of a first radially outermost surface of the outer race; a cage located in the channel and including a first plurality of apertures and a second radially outermost surface; and a plurality of rolling elements. Each rolling element in the plurality of rolling elements is disposed in a respective aperture included in the first plurality of apertures and extends radially past the second radially outermost surface. 
         [0009]    According to aspects illustrated herein, there is provided a method of axially displacing a ball bearing disposed in a housing and including an outer race and an inner race through which a shaft passes, including: contacting the housing with a plurality of rolling elements disposed in a plurality of apertures in a cage wrapped about an outer surface of the outer race; contacting the outer surface of the outer race with the plurality of rolling elements; axially displacing the shaft; and rolling the plurality of rolling elements within the plurality of apertures so that the ball bearing axially displaces with the shaft and with respect to the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying figures, in which: 
           [0011]      FIG. 1  is a perspective view of a cylindrical coordinate system demonstrating spatial terminology used in the present invention; 
           [0012]      FIG. 2  is a perspective view of bearing  20  of the present invention; 
           [0013]      FIG. 3  is a perspective view of bearing  20  with cage  30  removed; 
           [0014]      FIG. 4  is a perspective view of cage  30  with rolling elements  40  removed; and, 
           [0015]      FIG. 5  is a cross-sectional view of cage  30  with rolling elements  40  taken generally along line  5 - 5  in  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. It is to be understood that the invention as claimed is not limited to the disclosed aspects. 
         [0017]    Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention. 
         [0018]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention. The assembly of the present invention could be driven by hydraulics, electronics, and/or pneumatics. 
         [0019]      FIG. 1  is a perspective view of cylindrical coordinate system  10  demonstrating spatial terminology used in the present invention. The present invention is at least partially described within the context of a cylindrical coordinate system. System  10  includes longitudinal axis  11 , used as the reference for the directional and spatial terms that follow. Axial direction AD is parallel to axis  11 . Radial direction RD is orthogonal to axis  11 . Circumferential direction CD is defined by an endpoint of radius R (orthogonal to axis  11 ) rotated about axis  11 . 
         [0020]    To clarify the spatial terminology, objects  12 ,  13 , and  14  are used. An axial surface, such as surface  15  of object  12 , is formed by a plane co-planar with axis  11 . Axis  11  passes through planar surface  15 ; however any planar surface co-planar with axis  11  is an axial surface. A radial surface, such as surface  16  of object  13 , is formed by a plane orthogonal to axis  11  and co-planar with a radius, for example, radius  17 . Radius  17  passes through planar surface  16 ; however any planar surface co-planar with radius  17  is a radial surface. Surface  18  of object  14  forms a circumferential, or cylindrical, surface. For example, circumference  19  is passes through surface  18 . As a further example, axial movement is parallel to axis  11 , radial movement is orthogonal to axis  11 , and circumferential movement is parallel to circumference  19 . Rotational movement is with respect to axis  11 . The adverbs “axially,” “radially,” and “circumferentially” refer to orientations parallel to axis  11 , radius  17 , and circumference  19 , respectively. For example, an axially disposed surface or edge extends in direction AD, a radially disposed surface or edge extends in direction R, and a circumferentially disposed surface or edge extends in direction CD. 
         [0021]    Adverting now to the figures,  FIG. 2  is a perspective view of bearing  20 . Bearing  20  broadly comprises outer ring  22 , seal  25 , inner race  26 , cage  30 , and rolling elements  40 . As seen in the figure, cage  30  is operatively arranged on outer ring  22  to enable axial expansion of a rotating shaft (not shown) passing through inner race  26 . Additionally, rolling elements  40  are retained and secured within cage  30  after cage  30  is secured to outer race  22 . It is important to note that outer race  22  can rotate independently of inner race  26  due to internal rolling elements (not shown) arranged between outer race  22  and inner race  26 . Seal  25  is arranged between outer race  22  and inner race  26  to prevent contaminants from interacting with the internal rolling elements. While in operation, bearing  20  is arranged between a housing (not shown) and the rotating shaft, with rolling elements  40  engaged with the housing and surface  28  of inner race  26  engaged with the rotating shaft Inner race  26  rotates about axis  50  while in operation. Rolling elements  40  are secured within cage  30  to enable free rotation of each individual rolling element  40  enabling bearing  20  to be axially displaced along axis  50  without inducing a preload on bearing  20 . Due do the arrangement of cage  30  and rolling elements  40 , a preload cannot be induced on bearing  20  since bearing  20  can be axially displaced to match the axial expansion of the rotating shaft. 
         [0022]      FIG. 3  is a perspective view of bearing  20  with cage  30  removed. As shown in the figure, circumferentially disposed channel  22   a  forms portion  41   a  of radially outermost surface  41  of the outer race. Channel  22   a  is axially disposed between rim  23  and rim  24  of outer race  22 . When cage  30  is arranged within channel  22   a  and rolling elements  40  are retained within cage  30  (shown in  FIG. 2 ), rolling elements  40  engage portion  41   a  of outer race  22  and enable bearing  20  to be axially displaced. Cage  30  is axially secured to outer race  22  by rim  23  and rim  24 . In order to ensure rolling elements  40  are the only components of bearing  20  in contact with the housing, rolling elements  40  extend radially past rims  22  and  23 . 
         [0023]      FIG. 4  is a perspective view of cage  30  with rolling elements  40  removed. Cage  30  includes apertures  42  which are tapered through-bores that enable rolling elements  40  to engage the surface of the housing and surface  41   a  of outer race  22  (shown in  FIG. 3 ). Since apertures  42  are tapered such that apertures  42  have a smaller diameter on radially outermost surface  32  when compared to the diameter of apertures  42  on radially inner most surface  44 , rolling elements  40  are snapped into cage  30  and retained by apertures  42  and surface  22   b  of outer race  22  (shown in  FIG. 3 ). It should be appreciated however, that the use of different arrangements of apertures  42  is possible and considered to be within the scope of the invention as claimed. In an example embodiment, cage  30  is manufactured from a single piece of flexible material such as plastic, but other materials can be used. Gap  35  enables cage  30  to be snapped into channel  22   a  of outer race  22  while cage  30  remains a single component. In an example embodiment, cage  30  includes two halves which are secured together within channel  22   a  of outer race  22 . In an example embodiment: apertures  42   a  extend circumferentially about the cage (two example apertures are shown) and are circumferentially aligned with each other; apertures  42   b  extend circumferentially about the cage (two example apertures are shown) and are circumferentially aligned with each other; and the respective apertures  42   a  and  42   b  are not aligned with each other in axial direction AD. 
         [0024]      FIG. 5  is a cross-sectional view of cage  30  with rolling elements  40  taken generally along line  5 - 5  in  FIG. 4 . As shown in the figure, apertures  42  are tapered radially outward to ensure rolling elements  40  are retained within cage  30 . Additionally, it can be seen that rolling elements  40  extend radially outward at a greater distance than surface  32  of cage  30 . 
         [0025]    In order to install rolling elements  40  into cage  30 , cage  30  is arranged within channel  22   a  of outer race  22  (shown in  FIG. 2 ). Rolling elements  40  are snapped into apertures  42  of cage  30 , with cage  30  being made of a flexible material. 
         [0026]    Advantageously, bearing  20  address the binding problem noted above. That is, as a shaft passing through bearing  20  and essentially fixed to inner race  26  axially expands, for example due to heating of the shaft, elements  40  in cage  30  enable cage  30  and bearing  20 , as a whole, to slide along the housing, rather than having outer race  22  bind against the housing. 
         [0027]    It will be appreciated that various aspects of the above-disclosed invention and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           20  bearing 
           22  outer race 
           22   a  channel 
           22   b  surface 
           23  rim 
           24  rim 
           25  seal 
           26  inner race 
           28  surface 
           30  cage 
           32  surface 
           35  gap 
           40  rolling elements 
           41  radially outermost surface 
           41   a  portion of radially outermost surface 
           42  apertures 
           42   a  apertures 
           42   b  apertures 
           44  surface 
           50  axis