Abstract:
A center support assembly includes a bearing that supports a driveshaft for rotation about an axis. A shield is fixed to the bearing and a seal is positioned between the shield and the bearing. The shield and seal cooperate to retain lube within the bearing and prevent external contaminants from entering the bearing. A lube passage is formed between an outer surface of the bearing and an inner surface of the shield. At least one externally accessible fitting is in fluid communication with the lube passage and is used to supply additional lubricant to the bearing when needed.

Description:
TECHNICAL FIELD 
     This invention generally relates to a center support assembly for a vehicle driveline. 
     BACKGROUND 
     Vehicle drivelines typically include a driveshaft that extends a relatively long distance along a longitudinal length of a vehicle. The driveshaft is usually composed of multiple shafts that are coupled together, and which are supported at spaced locations along a vehicle frame. A center support assembly supports the driveshaft for rotation about a driveshaft axis at one of the spaced locations. 
     The center support assembly includes a roller bearing that provides structural support for the driveline while accommodating high speed rotation of the driveshaft. The support assembly includes a resilient cushion that is received around the roller bearing, and which is supported within a bracket that secures the center support assembly to the frame. In order to operate effectively, the roller bearing requires a sufficient amount of lubrication and should be protected from environmental contaminants such as water, dust, debris, etc. 
     In one example, a permanently sealed bearing is used to provide lubricant retention and contaminant exclusion. Such a configuration is not sufficiently effective from service life expectations in severe applications such as when the bearing is operating while being immersed in water or mud. 
     SUMMARY 
     A self-aligning bearing can be re-supplied with lubricant by forming a lube passage between the bearing and a shield attached to the bearing. The lubricant is supplied via at least one externally accessible fitting to the lube passage which directs the lubricant to the bearing. 
     In one example, a center support assembly for the bearing supports a driveshaft for rotation about an axis. The shield is mounted to the bearing and a seal is positioned between the shield and the bearing. The lube passage is formed between an inner surface of the shield and an outer surface of the bearing. At least one fitting is in fluid communication with the lube passage and is externally accessible to supply lubricant to the bearing as needed. 
     In one example, at least one fitting comprises a plurality of fittings that are in fluid communication with the lube passage. 
     In one example, a resilient cushion supports the bearing within a bracket. The bracket mounts the bearing to a vehicle structure. In one configuration, the fitting extends through both the bracket and the resilient cushion. In another configuration, the fitting only extends through the bracket. 
     In one example, the bearing has a fore side and an aft side and the shield includes first and second shield members with the first shield member being attached to the bearing at the fore side and the second shield member being attached to the bearing at the aft side. The lube passage includes a first passage formed between the first shield member and the bearing and a second passage formed between the second shield member and the bearing. The fitting supplies lubricant to both the first and second passages. 
     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a driveshaft supported within a center support assembly with a self-aligning bearing. 
         FIG. 2  is a front cross-sectional view of the center support assembly. 
         FIG. 3  is a section view taken along lines  3 - 3  of  FIG. 2 . 
         FIG. 4  is a partial cross-sectional view of an upper portion of the center support assembly. 
         FIG. 5  is a section view taken along lines  5 - 5  of  FIG. 3 . 
         FIG. 6  is a magnified view of corresponding section as indicated in  FIG. 5 . 
         FIG. 7  is a front cross-sectional view of another example of a center support assembly. 
         FIG. 8  is a side cross-section view of another example of a center support assembly. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a center support assembly  10  that includes a bracket  12  that is adapted to be attached to a vehicle structure  14 , such as a frame rail or frame bracket for example, with fasteners  16 . The bracket  12  retains a resilient cushion  18 . A driveshaft  20  is supported within a bearing  22  for rotation about an axis A. The bearing  22  is mounted within the cushion  18  such that angular movement of the driveshaft  20  that varies off of being centered along axis A is accommodated by the resiliency of the cushion  18 . A protective assembly  24  is mounted over each side of the bearing  22  to protect the bearing  22  from external environmental contaminants. 
     For further explanation of one example of a self-aligning bearing attention is directed to U.S. Pat. No. 6,379,048 which is assigned to the assignee of the present invention and which is hereby incorporated by reference in its entirety. 
     As shown in  FIG. 2 , the bracket  12  includes tabs  26  that are used to hold the cushion  18  in place. The cushion  18  includes a plurality of openings  28  to further enhance resiliency; however, the cushion  18  could also comprise a resilient solid structure. A fitting  30  extends through the bracket  12  and the cushion  18  to interface with the protective assembly  24 . The fitting  30  is accessible from an external location to add lubricant to the bearing  22  as needed. This will be discussed in greater detail below. 
       FIG. 3  shows a vertical section taken along lines  3 - 3  as indicated in  FIG. 2 . The protective assembly  24  includes a first assembly  24   a  that is attached to a fore side of the bearing  22  and a second assembly  24   b  that is attached to an aft side of the bearing  22 . These assemblies are sometimes referred to as “clamshells.” Further, references to “fore” indicate a direction that is toward a front of a vehicle and references to “aft” indicate a direction that is toward a rear of the vehicle. The first  24   a  and second  24   b  assemblies each include a seal  34  that is positioned between a respective shield  32  and the bearing  22 . The cushion  18  surrounds and extends circumferentially around the outer surfaces of the protective assembly  24  and bearing  22 . The bearing  22  is shown schematically in  FIG. 3 . 
       FIG. 4  shows the protective assembly  24  and bearing  22  in greater detail. In the example shown, the bearing  22  comprises a roller bearing having an inner race  36  fixed for rotation with the driveshaft  20  and an outer race  38  that is fixed to the shield  32 . Roller elements  40  are supported between the inner  36  and outer  38  races as known. 
     The shield  32  includes a first portion  42  that extends in a radial direction inward toward the axis A and a second portion  44  that extends in an axial direction over an outer surface  46  of the outer race  38 . The seal  34  maintains sealing contact with the inner race  36  and an inner surface of the first portion  42  of the shield  32 . The seal  34  can have various configurations and can be attached to either the shield  32  or the bearing  22 . For further explanation of a seal as used in the self-aligning bearing attention is directed to U.S. Pat. No. 7,097,363 which is assigned to the assignee of the present invention and which is hereby incorporated by reference in its entirety. 
     In one example, the shield  32  is a metal stamping that is pressed onto the outer surface  46  of the outer race  38 . This outer surface  46  comprises the outermost peripheral surface of the bearing  22 . The shield  32  forms an annulus volume adjacent the outer race  38  in which lubricant or grease G is packed. The seals  34  cooperate with the shield  32  to minimize leakage of the lubricant G and to provide a barrier to external environmental contamination. 
     As shown in  FIGS. 5 and 6 , the fitting  30  serves as a mechanism that can replenish the barrier lubricant G to further prevent contaminants from penetrating into the bearing  22 . A lubrication (lube) passage  50  is formed between the shield  32  and the outer race  38  of the bearing  22 . The lubrication passage  50  includes a first passage that is between the shield  32  of the fore side of the bearing  22  and the outer race  38  and a second passage that is between the shield  32  of the aft side of the bearing  22  and the outer race  38 . The fitting  30  is positioned to supply lubricant to both the first and second passages. In the example shown, the fitting  30  is positioned generally centrally between the fore  24   a  and aft  24   b  protective assemblies such that lubricant can be easily and efficiently supplied to the lubrication passages extending to both the fore and aft sides of the bearing  22 . However, the fitting  30  could be located in other locations, which will be discussed in greater detail below. 
     When needed, such as during a service or maintenance operation, lubricant is supplied to the bearing  22  via the fitting  30 . The lubricant replenishes any grease G that has been depleted from the annulus volume near the outer race  38  as well as re-supplying lubricant to the bearing elements themselves. The seals  34  and shields  32  are configured such that during service, any contaminated lubricant can be pumped out of the bearing  22  with a fresh supply of lubricant replacing the pumped out lubricant. 
     In the example shown in  FIGS. 2-6 , the fitting includes a body  60  that extends through both the resilient cushion  18  and the bracket  12 . Thus, the fitting  30  is embedded within the cushion  18 .  FIG. 7  shows alternate locations of the fitting  30 . Further, more than one fitting  30  can be used to supply lubricant to the bearing  22 . An example of multiple fittings could include any of the various locations shown in  FIG. 7 . 
       FIG. 8  shows an example where the fitting only extends through the shield  32 . The fitting  30  can extend through the first portion  42  of the shield  32  on the fore or aft side of the bearing. Further, multiple fittings  30  could be used on each of the fore and aft sides, or on both of the fore and aft sides. Also, fittings  30  on one bearing  22  could include a fitting that extends through both the cushion and bracket in combination with a fitting that extends only through the shield. 
     Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.