Abstract:
A roller bearing assembly includes an annular outer ring with first and second outer ring shoulders that define a first raceway in the outer ring. An annular inner ring may be disposed substantially concentrically within the outer ring, the inner ring including a base portion and first and second inner ring shoulders that extend from and are integral with the base portion to define a second raceway in the inner ring. A plurality of rolling elements may be arranged between the inner ring and outer ring and within the first and second raceways to rotatably couple the outer ring to the inner ring.

Description:
TECHNICAL FIELD 
     The present invention generally relates to roller bearing assemblies and roller bearing assembly methods, and more particularly relates to roller bearing assemblies and roller bearing assembly methods that are non-separable and full complement. 
     BACKGROUND 
     A rolling element bearing assembly carries a load by placing round elements between two members, such as inner and outer rings. The rolling movements of the rolling elements enable the two rings to rotate relative to one another with reduced resistance and sliding. Two types of assemblies are roller bearing assemblies and ball bearing assemblies. A roller bearing assembly uses cylinder-shaped rolling elements, while ball bearing assemblies use spherical-shaped rolling elements. In general, roller bearing assemblies have a higher radial load capacity as compared to ball bearing assemblies. 
     Design considerations for roller bearing assemblies include manufacture, assembly, installation, and operation. Assembly, in particular, may be difficult. A full complement of individual rolling elements must be arranged between the two rings. It is further advantageous if the assembled roller bearing assembly is non-separable to facilitate installation and operation. Conventionally, assembly of roller bearing assemblies required cages or other types of retention mechanisms and/or resulted in separable assemblies or assemblies that experienced undesirable issues. 
     Accordingly, it is desirable to provide an improved full-complement roller bearing assembly that is non-separable after assembly. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention. 
     BRIEF SUMMARY 
     In accordance with an exemplary embodiment, a roller bearing assembly includes an annular outer ring with first and second outer ring shoulders that define a first raceway in the outer ring. An annular inner ring may be disposed substantially concentrically within the outer ring, the inner ring including a base portion and first and second inner ring shoulders that extend from and are integral with the base portion to define a second raceway in the inner ring. A plurality of rolling elements may be arranged between the inner ring and outer ring and within the first and second raceways to rotatably couple the outer ring to the inner ring. 
     In accordance with another exemplary embodiment, a method is provided for assembling a roller bearing assembly. The assembly may include an outer ring with an outer raceway, an inner ring with an inner raceway, and a plurality of rolling elements for rotatably coupling the outer ring to the inner ring. The method may include comprising the steps of arranging the rolling elements within the outer raceway of the outer ring; heating the rolling elements and the outer ring so as to expand the outer raceway; and assembling the inner ring concentrically within the outer ring such that the rolling elements are arranged at least partially within the inner and outer raceways. 
     In accordance with another exemplary embodiment, a roller bearing assembly includes an annular outer ring with first and second outer ring shoulders that define a first raceway in the outer ring. An annular inner ring may be disposed substantially concentrically within the outer ring, the inner ring including a base portion and first and second inner ring shoulders that extend from and are integral with the base portion to define a second raceway in the inner ring. The first raceway may have a first width and the second raceway may have a second width that is greater than the first width. A plurality of rolling elements may be arranged between the inner ring and outer ring and within the first and second raceways to rotatably couple the outer ring to the inner ring. The first ring has a first axis, and the rolling elements have second axis that are substantially parallel to the first axis. The first and second inner ring shoulders may each have a height sufficient to clear the rolling elements during assembly and to maintain the rotatable coupling with the outer ring after assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  is an isometric view of a roller bearing assembly in accordance with an exemplary embodiment; 
         FIG. 2  is a cross-sectional view of the roller bearing assembly of  FIG. 1  in accordance with an exemplary embodiment; 
         FIG. 3  is a close-up elevation view of a portion of the cross-sectional view of the roller bearing assembly of  FIGS. 1 and 2  in accordance with an exemplary embodiment; and 
         FIG. 4  is a method of assembling a roller bearing assembly in accordance with an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
       FIG. 1  is an isometric view of a roller bearing assembly  100  in accordance with an exemplary embodiment. The roller bearing assembly  100  generally includes an annular outer ring  110  and an annular inner ring  120  arranged concentrically within the outer ring  110 . A number of rolling elements  130  are arranged between the outer ring  110  and the inner ring  120  such that the outer ring  110  is rotatably coupled to the inner ring  120 . In general, the inner ring  120  is mounted to a first member such as a shaft and the outer ring  110  is coupled to a second member such as a housing to enable relative rotational movement between the first and second members. In one exemplary embodiment, roller bearing assembly  100  may form part of a pneumatically actuated aircraft engine valve, and provides an enhanced load carrying capability in a relatively small possible package. Of course, other applications may also be provided. As noted below, in some exemplary embodiments, the roller bearing assembly  100  does not require spacers to maintain separation between the rolling elements  130  and/or a cage to retain the rolling elements within the outer and/or inner rings  110 ,  120 . 
     The rolling elements  130  include a number of elements, which in one embodiment, is a full complement of rolling elements. That is, as many rolling elements as possible are respectively arranged between the outer and inner circumferences of the outer and inner rings  110 ,  120 . The rolling elements  130  are generally cylindrical. In further embodiments, the rolling elements  130  can be ball bearings and/or needle bearings. 
     In general, the outer and inner rings  110 ,  120  share a first axis  140 , and the rolling elements  130  each have an axis (e.g., axis  142 ) that is parallel to the first axis  140 . As such, the roller bearing assembly  100  has non-tapered rolling elements  130 . In one exemplary embodiment, each rolling element has a width of 6 mm and a diameter of 6 mm, although other dimensions may be used. In one exemplary embodiment, the roller bearing assembly  100  can be manufactured with steel. 
       FIG. 2  is a cross-sectional view of the roller bearing assembly  100  of  FIG. 1  in accordance with an exemplary embodiment. As best shown by  FIG. 2 , the outer ring  110  has two outer ring shoulders, which in this embodiment are guide shoulders  212 ,  214  on either side of a base portion  216 . The guide shoulders  212 ,  214  and base portion  216  define a raceway  218  in the outer ring  110 . The raceway  218  receives the rolling elements  130  and the guide shoulders  212 ,  214  guide the rolling elements  130  around the raceway  218  in the outer ring  110 . The guide shoulders  212 ,  214  additionally function to retain the rolling elements  130  within the outer ring  110  of the roller bearing assembly  100 . As shown in  FIG. 2 , the outer ring  110  has an outer diameter of  250  and an inner diameter of  252 . Moreover, the outer ring  110  and rolling elements  130  together have an inner diameter of  254 . 
     The inner ring  120  has two inner ring shoulders, which in this embodiment are snap shoulders  222 ,  224  on either side of a base portion  226 . The snap shoulders  222 ,  224  and base portion  226  define a raceway  228  in the inner ring  120 . The raceway  228  receives the rolling elements  130  such that the rolling elements  130  rotate around the inner ring  120 . The snap shoulders  222 ,  224  additionally function to retain the rolling elements  130  within the outer ring  110  of the roller bearing assembly  100 , if necessary, during installation and operation. As also shown in  FIG. 2 , the inner ring has an outer diameter of  256  and an inner diameter of  258 . 
       FIG. 3  is a close-up elevation view of a portion of the cross-sectional view of the roller bearing assembly  100  of  FIGS. 1 and 2  in accordance with an exemplary embodiment. In particular,  FIG. 3  illustrates the guide shoulders  212 ,  214  of the outer ring  110  and the snap shoulders  222 ,  224  of the inner ring  120 . 
     In one exemplary embodiment, the guide shoulders  212 ,  214  are integral with base portion  216 . That is, the guide shoulders  212 ,  214  are formed in one piece with the outer ring  210 . The guide shoulders  212 ,  214  have a width  310  that is approximately equal to the width  330  of each rolling element  130  such that the guide shoulders  212 ,  214  function to guide the rolling elements  130  around the outer ring  110 . In one exemplary embodiment, the height  312  of the guide shoulders  212 ,  214  are approximately 28% of the roller diameter, although other dimensions are possible. 
     In one exemplary embodiment, the snap shoulders  222 ,  224  are integral with base portion  226 . That is, the snap shoulders  222 ,  224  are formed in one piece with the inner ring  120 . The snap shoulders  222 ,  224  have a width  320  that is larger than the width  330  of each rolling element  130 . In one exemplary embodiment, the snap shoulders  222 ,  224  have a width  320  that is approximately 144% of the width  330  of the roller element  130 , although other dimensions are possible. As such, in one exemplary embodiment, the snap shoulders  222 ,  224  do not contact the rolling elements  130  during operation. If necessary, however, the snap shoulders  222 ,  224  retain the rolling elements  130  in an axial direction. Accordingly, the raceway  228  of the inner ring  120  is wider than the raceway  218  of the outer ring  110 . As discussed in further detail below, in general, the snap shoulders  222 ,  224  have a height  322  sufficient to clear the rolling elements  130  during assembly and to maintain the rotatable coupling with the outer ring  110  after assembly. In general, this height  322  is less than a height  312  of the guide shoulders  212 ,  214 . In one exemplary embodiment, the height  312  of the snap shoulders  222 ,  224  are approximately about 0.5% of the diameter of the rolling element  130 . In other exemplary embodiments, the height  312  may be larger or smaller relative to the rolling element  130 , depending on the application and manufacturing requirements. 
       FIG. 4  is a method  400  of assembling a roller bearing assembly, such as the roller bearing assembly  100  discussed above. As such, reference is additionally made to  FIGS. 1-3 . In a first step  405 , the rolling elements  130  are assembled within the raceway  218  of the outer ring  110 . The full complement of rolling elements  130  are installed within the raceway  218 . At this stage, the bearing elements  130  may be held within the raceway  218  with a tool that enables retention of the bearing elements during some of the subsequent steps. 
     In a second step  410 , the rolling elements  130  and outer ring  110  are heated so as to expand the inner diameter  254  of the rolling elements  130  and outer ring  110 . As will be discussed below, the rolling elements  130  and outer ring  110  are heated such that the inner diameter  254  of the rolling elements  130  and outer ring  110  is greater than the outer diameter  258  of the inner ring  120 . In one exemplary embodiment, the rolling elements  130  and outer ring  110  are heated to a temperature of approximately 300°, although other temperatures can be used. 
     In a third step  415 , the inner ring  120  is assembled concentrically within the outer ring  110 . Particularly, as noted above, the inner diameter  254  of the rolling elements  130  and outer ring  110  after the heating and expansion is greater than the outer diameter  258  of the inner ring  120  at room temperature. As such, the inner ring  120  may be inserted into the outer ring  110  and rolling elements  130  to form the roller bearing assembly  100 . As noted above, the snap shoulders  222 ,  224  of the inner ring  120  have a height to facilitate this insertion. The height should be sufficient to retain the rolling elements  130  at room temperature, but relatively to small to enable assembly with the outer ring  110  and rolling elements  130 . 
     Even if the inner diameter  254  of the rolling elements  130  and outer ring  110  after the heating and expansion is not greater than the outer diameter  258  of the inner ring  120  at room temperature, the snap shoulders  222 ,  224  may be forced or “snapped” over the rolling elements  130  to complete the roller bearing assembly  100 . 
     In a fourth step  420 , the roller bearing assembly  100 , particularly the outer ring  110  and rolling elements  130 , is allowed to cool and contract. After contraction, the rolling elements  130  are arranged at least partially within the raceway  228  of the inner ring  120 . Alternatively, the roller bearing assembly  100  can be cooled, for example, by other mechanisms, such as liquid nitrogen. When the roller bearing assembly  100  is cooled, it provides a non-separable, full complement roller bearing assembly. In one exemplary embodiment, the roller bearing assembly  100  does not require additional retention components, such as separate retaining rings that can pop out or separate inner ring shoulders. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.