Abstract:
An axle assembly of a vehicle including a differential assembly, an axle tube extending outwardly from a first side of the differential assembly and defining an axle bore, an axle shaft rotatably received in the first axle tube and defining an annular groove extending radially inwardly from its outer surface, a retaining nut axially fixed to the distal end of the first axle tube, and a snap ring received in the annular groove of the first axle shaft, wherein the snap ring abuts the retaining nut, thereby preventing out ward motion of the first axle shaft with respect to the first axle tube.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure relates generally to solid axle assemblies for vehicles and, more specifically, to bearing assemblies that are utilized on the wheel end sections of such solid axle assemblies. 
       BACKGROUND 
       [0002]    Salisbury solid axles are often used in passenger trucks and sport utility vehicles. Salisbury axles are unique in the fact that the axle transmits driving torque to the wheel as well as carries and transmits both radial and axial thrust loads. 
         [0003]    As shown in  FIG. 1 , many existing wheel end bearings  10  for use with solid vehicle axles include an outer cup  11  that is press-fit into the corresponding axle tube  12  to maintain location and define an outer raceway for the corresponding rollers  13 . No additional retention features are required for this type of wheel end bearing  10  in that the bearing only handles radial loads. Lubrication for wheel end bearing  10  is provided by the same oil sump that provides lubrication to the differential gears  15  ( FIG. 2 ) that are disposed at the center section of the axle assembly. To maintain lubrication, an oil seal  14  is press-fitted outboard of the wheel end bearing in axle tube  12 . 
         [0004]    Radial wheel end loads are handled primarily at wheel end bearing  10 , whereas axial loads are not. Rather, as best seen in  FIGS. 2 through 4 , axial loads are transmitted along axle shaft  16 . Typically, “C Locks”  18  are utilized to resist outward axial loading and a cross shaft  20  disposed between the opposing axles in a housing  25  of differential  17  absorbs inward axial loading. A typical C Lock includes a heavy annular lock ring  19  received in an annular groove  21  formed on the inboard end of a corresponding axle shaft  16 . In the fully assembled configuration ( FIG. 3 ), annular lock ring  19  is further received in an annular recess  23  formed in an end face of a corresponding differential gear  15 . During normal operations, inward axial loading has a higher magnitude than outward axial loading due to vehicle dynamics during cornering. When outward axial load on axle shaft  16  occurs, axle shaft  16  attempts to move outwardly from axle tube  12 , which causes annular lock ring  19  of the corresponding C Lock  18  to push on the corresponding differential side gear  15 . Ultimately, the outward axial load is dispersed through differential carrier bearings  24  to housing  25  of the differential, as shown in  FIG. 4 . 
         [0005]    When inward axial loading is generated from vehicle cornering, an end face  27  of axle shaft  16  thrusts against differential cross shaft  20 , as best seen in  FIG. 2 . In turn, the inward axial loading is transmitted through differential carrier bearings  24 , as shown in  FIG. 4 . 
         [0006]    The present invention recognizes and addresses considerations of prior art constructions and methods. 
       SUMMARY 
       [0007]    One embodiment of an axle assembly of a vehicle, includes a differential assembly, a first axle tube extending outwardly from a first side of the differential assembly, the first axle tube including a proximal end adjacent the differential assembly, an opposite distal end, and an axle bore extending therebetween, a first axle shaft rotatably received in the first axle tube, the first axle shaft including a proximal end disposed in the differential assembly, an opposite distal end extending outwardly from the distal end of the first axle shaft, and an annular groove extending radially inwardly from its outer surface, a retaining nut axially fixed to the distal end of the first axle tube, and a snap ring received in the annular groove of the first axle shaft, wherein the snap ring bears against the retaining nut, thereby preventing outward motion of the first axle shaft with respect to the first axle tube. 
         [0008]    Another embodiment of an axial thrust assembly for use with an axle assembly of a vehicle having an axle tube and an axle shaft rotatably received therein includes a retaining nut axially fixed to a first end of the axle tube, and a snap ring received in an annular groove defined in an outer surface of the axle shaft, wherein the snap ring bears against the retaining nut, thereby preventing outward motion of the first axle shaft with respect to the first axle tube 
         [0009]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended drawings, in which: 
           [0011]      FIG. 1  is a partial cross-sectional view of a wheel end section of a prior art solid axle assembly; 
           [0012]      FIG. 2  is a partial perspective view of the prior art axle shaft shown in  FIG. 1  and a corresponding differential; 
           [0013]      FIG. 3  is a partial perspective view of the prior art axle shaft and differential shown in  FIG. 2 , including a cross shaft of the differential; 
           [0014]      FIG. 4  is a cut away side view of the prior art axle shaft and differential shown in  FIG. 2 ; 
           [0015]      FIG. 5  is a partial cross-sectional view of a wheel end section of a solid axle assembly including an axial thrust assembly in accordance with an embodiment of the present invention; and 
           [0016]      FIG. 6  is an exploded perspective view of the axial thrust assembly shown in  FIG. 5 . 
       
    
    
       [0017]    Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention according to the disclosure. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation, not limitation, of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope and spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0019]    Referring now to  FIGS. 5 and 6 , a wheel end axial thrust assembly  100  for use with a solid vehicle axle in accordance with an embodiment of the present disclosure includes a radial bearing assembly  150 , a snap ring  110 , a thrust washer  140 , and a retaining nut  160  disposed on the wheel end of an axle shaft  120  and corresponding axle tube  130 , as discussed in greater detail below. Axial thrust assembly  100  handles axial thrust forces that act on axle shaft  120  in the outward direction, thereby obviating the need to utilize C-locks  18  ( FIGS. 2 and 3 ) that are typically found on existing solid axle assemblies. 
         [0020]    As noted above, radial bearing  150  includes an outer cup  152  that defines a cylindrical outer race  154  for needle rollers  151 . A first annular flange  156  and second annular flange  158  extend radially-inwardly from opposite ends of outer race  154 . Outer cup  152  is preferably a machined and ground component made from a carburized grade of steel to enhance control of the press-fit, bearing clearances, and increase allowable hoop stresses. As best seen in  FIG. 5 , outer cup  150  is received in a bore  134  of axle tube  130 . Although radial bearing assembly  150  does not handle either inward or outward axial thrust forces that act on axle shaft  120 , outer cup  152  is press-fit into bore  134  to maintain the desired position within axle tube  130 . As well, outer cup  130  is positioned within bore  134  of axle tube  130  so that an inner race for the plurality of rollers  151  is formed by a narrowed portion of axle shaft  120 , as discussed in greater detail below. 
         [0021]    Each needle roller  151  includes a cylindrical rolling surface extending between a first end face  153  and a second end face  155 . Each first and second end face  153  and  155  is transverse to a longitudinal center axis of the corresponding needle roller  151 . As such, when needle rollers  151  are disposed between outer cup  152  and the outer surface of axle shaft  120 , first end faces  153  and second end faces  155  are parallel to first annular flange  156  and second annular flange  158  of outer cup  152 . 
         [0022]    Snap ring  110  is annular in shape and defines a central bore  115  that is received in an annular groove  122  on axle shaft  120 . Annular groove  122 , and therefore snap ring  110 , is disposed outboard of radial bearing assembly  150  on an enlarged end portion  124  of axle shaft  120 . The diameter of enlarged end portion  124  of axle shaft  120  is greater than the diameter of the inboard portion that forms the remainder of axle shaft  120 . The increased diameter helps to minimize any additional stresses due to the formation of annular groove  122  to receive snap ring  110  and its resistance to outwardly directly axial thrust forces that act on axle shaft  120 . A split  114  in snap ring  110  allows it to be slid over the transition between axle shaft  120  and its enlarged end portion  124 . 
         [0023]    A thrust washer  140  is preferably disposed outboard of, and adjacent to, an end face  112  of snap ring  110 . An outermost edge  142  and innermost edge  144  of thrust washer  140  are smaller than the inside diameter of axle tube  130  and larger than the outside diameter of the axle shaft&#39;s enlarged end portion  124 , respectively, so that thrust washer  140  is free to rotate about axle shaft  120 . Thrust washer  140  helps to reduce friction, and therefore drag, between snap ring  110  and retaining nut  160 . Note, however, in alternate embodiments, thrust washer  140  is not required. 
         [0024]    Retaining nut  160  is threadedly received on the wheel end of axle tube  130 . Retaining nut  160  includes a cylindrical body  162  with an open end defining a threaded bore  164 , a radial flange  166  depending inwardly from the end of cylindrical body  160  opposite its open end, and an axial flange  168  depending inwardly from the inner perimeter of radial flange  166 . As best seen in  FIG. 5 , axial flange  168  is concentric with cylindrical body  162 , thereby defining an annular recess in which the outermost end of axle tube  130  is received as retaining nut  160  is threaded thereon. An annular end face  170  of the retaining nut&#39;s axial flange  168  serves as an abutment surface that comes into contact with an end face  148  of thrust washer  140  when outward axial thrust forces act on axle shaft  120 . As best seen in  FIG. 5 , an annular groove  172  is defined by the inside surface of the retaining nut&#39;s cylindrical body  162 , adjacent its open end. An O-ring  190  is received in annular groove  172  and forms a seal with the outer surface of axle tube  160  to help retain lubricating fluids therein. Additionally, an oil seal  180  is press-fit in a bore defined by axial flange  168  of retaining nut  160  to help retain lubricating fluids in axle tube  130 . 
         [0025]    As best seen in  FIG. 5 , during vehicle operations, axial thrust forces acting on axle shaft  120  in the outward direction are transferred to retaining nut  160  by way of snap ring  110 . Specifically, snap ring  110  moves outwardly with axle shaft  120  as it is received in annular groove  122  thereof. The outboard end face  112  of snap ring  110  abuts thrust washer  140 , which causes outboard end face  148  of thrust washer  140  to abut end face  170  of the retaining nut&#39;s axial flange  168 , thereby transferring the axial thrust force thereto. In turn, retaining nut  160  transfers the outwardly directed axial thrust force to axle tube  130  by way of the threaded connection therebetween. 
         [0026]    As previously discussed, inwardly directed axial thrust forces acting on axle shaft  150  are transferred from the innermost end of axle shaft  120  to a cross shaft  20  ( FIGS. 3 and 4 ) of the axle&#39;s differential. 
         [0027]    While one or more preferred embodiments of the invention are described above, it should be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit thereof. It is intended that the present invention cover such modifications and variations as come within the scope and spirit of the appended claims and their equivalents.