Abstract:
A bearing includes a first race including first and second segments, forming aligned pairs of first surfaces, spaced angularly about an axis; a second race including second surfaces, each second surface aligned with one of the pairs of first surfaces; balls, each ball contacting the surfaces of the first and second races; and a cage retaining each ball and engaging the first and second segments.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to a ball bearing that supports components in rotation, particularly in applications where axial thrust loads are present. 
     2. Description of the Prior Art 
     To improve power density, there is a need to maximize ball fill and contact load capacity over that in regular single row deep groove ball bearings (DGBBs) using the standard Conrad design and method of assembly. Holding split bearing race segments together for both shipping and assembly present a problem. 
     Greater radial load capacity using additional balls can be achieved having a slot in one or both of the bearing races. This allows more radial capacity than the Conrad design but it severely reduces axial capacity, which is inappropriate for applications in which thrust loads can force the balls out of the slot. 
     An alternative is to use split-ring ball bearings, where one of the races is split in the middle to allow for more balls to be assembled in it. Unfortunately, handling and assembly suffer as the two halves of the split race are not retained together until installation. This also allows for more opportunity for mechanical damage and contamination until the whole open assembly is closed. 
     SUMMARY OF THE INVENTION 
     A bearing includes a first race including first and second segments, forming aligned pairs of first surfaces, spaced angularly about an axis; a second race including second surfaces, each second surface aligned with one of the pairs of first surfaces; balls, each ball contacting the surfaces of the first and second races; and a cage connecting each ball, engaging the first and second segments with a force that holds the segments in mutual contact. 
     Either the inner or outer race is formed in one piece; the other race is formed in two segments. 
     Contact between the ball and whole race can be at one central point, or at two points as with a Gothic arch bearing. 
     The ball may contact one or both of the segmented races when the segmented races are asymmetric. 
     The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which: 
         FIG. 1  is an end view of a bearing with its component in spaced-apart relation; 
         FIG. 2  is a top view of a portion of the bearing of  FIG. 1 ; 
         FIG. 3  is an end view of an alternate configuration of the bearing of  FIG. 1 ; 
         FIG. 4  is an end view of an alternate configuration of the bearing of  FIGS. 1 and 2 ; 
         FIG. 5  is an end view of the bearing configuration of  FIG. 4  showing the split races spaced by unequal radial lengths from the ball; 
         FIG. 6  is an end view showing ball contact on the races, each over a single contact area; and 
         FIG. 7  is an end view showing ball contact on the solid race at multiple contact areas. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates a bearing  10  that is symmetrical about an axis  12 . The bearing includes an outer race  14 , split inner races  16 ,  18  and a cage  20 , formed with tabs  21 ,  22 , which extend laterally. Cage tab  21  includes a leg  23  and cage tab  22  includes a leg  24 . Each of the legs  23 ,  24  extends toward the axis  12  and overlaps the outer faces  26 ,  28  of the split races  16 ,  18  when the cage  20  is press-formed radially inward, thereby providing lateral continuity between races  16 ,  18 . 
     The gap  30  between the races  16 ,  18  is retained by press-forming the legs  23 ,  24  of the tabs  21 ,  22  such that the legs  23 ,  24  bear with a running clearance to the outer faces  26 ,  28  when the bearing  10  is in its assembled condition. The legs  23  and  24  are to have running clearance to the race surfaces, so as to retain the assembly in the uninstalled state, but minimize sliding friction in operation. A shaft/bore fastener may be used to close and/or preload the gap  30 , as with other bearings. The external shaft/bore fastener or some external device or preload would produce the axial force. 
     A spherical ball  32  enclosed by the races  14 ,  16 ,  18 , contacts at least a portion of the concave spherical inner surfaces  34 ,  36 ,  38  of races  14 ,  16 ,  18 . 
       FIG. 2  shows that the cage  20  is continuous about axis  12  and encircles each of the balls  32 . Each pair of tabs  21 ,  22  is in a circumferential location between the balls  32 . 
     In the bearing configuration shown in  FIG. 3 , split race  16  is formed with a rib  40 , which extends radially from the upper surface  42  of race  16  and along the circumference of surface  42 . Similarly, split race  18  is formed with a rib  44  that extends radially from the upper surface  46  of race  18  and along the circumference of race  18 . 
     The gap  30  between the races  16 ,  18  is closed by press-forming the legs  23 ,  24  of the tabs  21 ,  22  such that the legs bear with a running clearance to the outer lateral faces of ribs  40 ,  44  when the bearing  10  is in its assembled condition, thereby providing lateral continuity between races  16 ,  18 . 
     In the bearing configuration shown in  FIG. 4 , split race  16  is formed with a shoulder  50 , which extends along the circumference race  16 . Similarly, split race  18  is formed with a shoulder  52 , which extends along the circumference of race  18 . 
     The gap  30  between the races  16 ,  18  is retained by press-forming the legs  23 ,  24  of the tabs  21 ,  22  such that the legs bear with a running clearance relative to the outer lateral faces of shoulder  50 ,  52  when the bearing  10  is in its assembled condition, thereby providing lateral continuity between races  16 ,  18 . 
     In the bearing configuration shown in  FIG. 5  the split races  16 ,  18  are spaced by unequal radial lengths from the ball  32 . The internal radius of curvature of concave spherical surface  36  is shorter than the internal radius of curvature of concave spherical surface  38 , thereby producing a gap g1 between the outer surface of ball  32  and surface  36  that is smaller than the gap g2 between the outer surface of ball  32  and surface  38 . The centerpoint of the internal radius of curvature of concave spherical surface  36  may also be axially and/or radially offset in space from the internal radius of curvature of concave spherical surface  38 , thereby aligning gap g1 differently than gap g2 to allow for asymmetric loading and contact stress characteristics between ball  32  and surfaces  34 ,  36 ,  38 . 
     Due to the asymmetric race profiles of surfaces  36 ,  38 , pairs of bearings can be arranged such that greater radial and axial load capacity in one axial direction can be achieved in one member of the pair and greater radial and axial load capacity in the opposite axial direction can be achieved in the other member of the pair, thereby providing reactions bi-directional axial thrust loads at the bearing pair. 
       FIG. 6  is an end view showing contact between ball  32  and the races  14 ,  16 ,  18 . Because the radius of curvature of each concave spherical surface  34 ,  36 ,  38  is greater than the radius of the ball  32 , the range of contact on each race  14 ,  16 ,  18  occurs at a single contact area that is less than the entire area of each surface  34 ,  36 ,  38 . 
       FIG. 7  is an end view showing ball contact between ball  32  and the races  14 ,  16 ,  18 . Because the radius of curvature of each concave spherical surface  36 ,  38  is greater than the radius of the ball  32 , the range of contact on races  16 ,  18  occurs at a single contact area that is less than the entire area of surfaces  36 ,  38 . 
       FIG. 7  shows that the inner surface of race  14  has the form of a Gothic arch. Because the inner surface of race  14  comprises two spherical surfaces  60 ,  62  each having a center of curvature that is offset from the center of ball  32  and mutually non-coincident, the range of contact on race  14  occurs at multiple contact areas, the sum of the areas being less than the entire area of surfaces  60 ,  62 . 
     In each of the configurations, the one piece race, such as race  14 , may be either the inner race or the outer race, and the other race may comprise two parts, such as the race portions  16 ,  18 . 
     In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described.