Abstract:
A wheel end assembly including a live spindle secured to a wheel hub at an outboard end. A bearing surrounding the spindle and abutted against a shoulder on the spindle. Said bearing preloaded by a retention structure that slidably engages the bearing to compress the bearing against the shoulder. A clutch ring slidably engages splines associated with the live spindle and with an axle portion to connect and disconnect the axle to the live spindle and accordingly the wheel hub.

Description:
FIELD OF THE INVENTION 
     This invention relates to a wheel end assembly for a vehicle having optional two-wheel/four-wheel drive including wheel bearings used for rotatably mounting a wheel hub to a vehicle frame, and more particularly to the manner of retaining the bearings to the wheel hub. 
     BACKGROUND OF THE INVENTION 
     A recent advance in the development of wheel end assemblies for vehicles having optional two-wheel/four-wheel drive is the inboard positioning of the clutch mechanism. Such is described in the commonly owned U.S. Pat. No. 5,740,895. Whereas previously the axle protruded outwardly into the wheel hub whereat the wheel was mounted and a clutch ring within the wheel hub was actuated to connect and disconnect the axle from the hub, in the &#39;895 patent the wheel hub is provided with an inwardly extending integral spindle portion and the clutch ring and actuator therefor are positioned at the inboard end of the spindle portion. 
     In this inboard connection system, the inboard end of the spindle and an adjacent part of the axle are provided with matching splines and the clutch ring traverses between engagement with the splines of one only and then engagement with both spindle and axle. 
     The wheel hub is rotatably mounted to the vehicle suspension, e.g., the knuckle, with high performance bearings. A primary consideration is the proper mounting of the bearing. They need to be compressed, i.e., preloaded to a precise load, and maintained at that load. In the &#39;895 patent, preloading is provided by a spindle nut screwed onto the spindle at the outboard end. An integral flange at the inboard end of the spindle provides the splines for clutch ring engagement and also provides a shoulder against which the bearings are compressed. 
     A subsequent development disclosed in the U.S. Pat. No. 5,984,422 provides an integral flange at the outboard end. The inboard end is splined and a coupler having radially inwardly directed splines is slid onto the splined end of the spindle. The coupler is also provided with radially outwardly directed splines that provide for clutch ring engagement. A nut is screwed onto a threaded portion of the spindle&#39;s inboard end to compress/preload the coupler against the bearings and then the spindle end is roll formed against the nut to secure the nut and thereby maintain the preload on the bearings. 
     Alternate versions of the &#39;422 disclosure eliminate the nut and provide and maintain the preload of the bearings through direct roll forming of the spindle against the coupler. It will be appreciated that the manner of mounting the coupler to the spindle must provide rotative driving torque from the axle to the wheel hub which is typically accomplished by a matching spline fit between the coupler and the spindle and between the coupler and the clutch ring. 
     BRIEF DESCRIPTION OF THE PRESENT INVENTION 
     The present invention is directed to improved and alternative mechanism and structure primarily at the inboard end of the spindle for providing clutch ring engagement and preloading and maintenance of the preload of the bearings. 
     One version provides roll forming of the spindle end directly against the bearing with a coupler fitted (e.g., spline fit) to the inner diameter of the spindle and wrapping around and outside the roll formed end. (FIGS. 4 and 4 a ) 
     A second version provides the inboard end of the inner race of the bearings with inner splines (inwardly directed) fitted to the spindle, and exterior splines for receiving a clutch ring. (FIG. 5) 
     A third version provides an inner race with screw threads that screw onto the spindle. A lock ring secures the inner race of the bearing at the desired preload and the spindle end is provided with splines for receiving the clutch ring. (FIG. 6) 
     A fourth version provides a coupler having, e.g., dog lugs in axial engagement with the spindle end. The coupler is compressed against the bearing inner race and is roll formed under a lip provided on the inner diameter of the spindle end. (FIG. 7) 
     A fifth version provides a coupling that is spline fitted to the spindle and abuts the bearing race. A circular groove at the outer diameter of the spindle end is configured to receive a formed retention ring that is cam fitted to the groove to compress and retain the bearings. A variation to this version is the use of a split ring cam fit to slot and retained by a retainer band. (FIGS. 8 and 8 a ) 
     A sixth version provides a groove in the exterior diameter of the spindle end. A coupler slides into place over the groove and is then press fit into the groove and against the bearing race. Splines for clutch ring engagement are subsequently formed into the coupler exterior. (FIG. 9) 
     A seventh version provides the spindle end with fingers. A coupler has mated slots and slides onto the fingers and against the bearing race. The fingers are then press formed in the manner of a rivet head to secure and retain the preload on the bearings. (FIGS. 10 and 10A) 
     An eighth version provides spline or screw thread engagement of a coupler onto a spindle end and against the bearing race. Cavities are provided for receiving molten metal when the desired preload is obtained which hardens and fixes the coupler to the spindle. (FIG. 11) 
     A ninth version provides a desired interfit of a coupler to the spindle end and bearing race whereby as fitted the desired preload is achieved. The coupler is spin welded (friction welded) to the spindle end to maintain the preload. (FIGS. 12,  12 A and  12 B) 
     A tenth version provides a formed seat at the end of the spindle for receiving a mated coupler that is compressed against the bearing race and welded (conventional welding) to the spindle end. (FIGS. 13,  13 A and  13 B) 
     An eleventh version includes a coupler spine fit to the exterior of the spindle inboard end, a retainer screw threaded to the inner diameter of the spindle end, and a lock washer between the retainer and coupler that locks the retainer at the desired compression. (FIG. 14) This version in particular is also adapted for application to the outboard end of the spindle, i.e., an inboard flange providing a shoulder as illustrated in the &#39;895 patent. (FIG. 14A) 
     A twelfth version provides a spindle inner end configured in a polygonal form (hexagonal, octagonal, etc.) or other form such as double D or key and key slot, with a coupler similarly configured and fitted to the spindle end which is then roll formed against the coupler. (FIGS. 15 and 15A) 
     A thirteenth version provides the spindle end with a negative angle and a coupler is force fit onto the spindle end, e.g. the bearing being cold and the coupler heated to expand the inner circumference. (FIG. 16) Alternatively dowel pins can be force fit into the interfitted coupler and bearing. (FIG. 16A) 
     The above versions are all directed to the same desired end result, i.e., the preloading of wheel bearings, primarily from the inboard end of a wheel hub extension/spindle; and incorporating a coupler secured to the spindle and designed to be engaged by a clutch ring and thereby secured to an axle for four-wheel drive; and with a retention mechanism that insures retention of the preloaded force against the bearings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a vehicle having optional two-wheel/four-wheel drive capability in accordance with the invention; 
     FIG. 2 taken on section lines  2 — 2  of FIG. 1 illustrates a wheel end of the vehicle of FIG. 1 wherein the present invention is incorporated; 
     FIG. 3 illustrates the components of FIG. 2 in cross section and particularly the arrangement of the inboard end of the wheel hub/spindle whereat the coupler retention/bearing preload mechanism of the present invention is applied; and 
     FIGS. 4-16 are views of alternate embodiments of the invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates schematically a vehicle chassis including an engine E, a transmission  20 , a transfer case  22  and front and rear propeller shafts  24 ,  26  connected to front and rear differentials  28 ,  30  connected to front and rear axles  32 ,  34  that engage front and rear wheels  36 ,  38 . 
     A shift mechanism  40  interconnected to the transmission or the transfer case produces driving rotation or interrupts driving rotation from the engine E to propeller shaft  24  and thus to axles  32  and wheels  36 . It is desirable to also disconnect the wheels from the axles when the shift mechanism disconnects driving power from the engine. Otherwise the mechanism including propeller shaft  24  differential gears and differential  28  and axles  32  will be driven by wheels  36  resulting in undesired power loss and drive line wear. The invention is directed to the mechanism that connects/disconnects the axles  32  from the wheels  36 . 
     FIG. 2 illustrates somewhat schematically a wheel end assembly including a wheel  36 , wheel rim  42 , a brake rotor  44  and wheel hub  46 . The wheel hub is rotatably mounted to a knuckle  48  carried by a shock absorber  50 . 
     FIG. 3 is a sectional view of the wheel end assembly of FIG.  2 . As will be noted, the wheel hub  46  includes an integral outboard flange  52  which provides an outboard shoulder for wheel bearing  54 . The wheel bearing  54  rotatably supports the wheel hub  46  and wheel  36  (shown in FIG. 2) relative to the non-rotating knuckle  48  mounted to or part of the vehicle frame (not otherwise shown). 
     The wheel hub has an inwardly directed extension  56  which will be sometimes referred to as a spindle or spindle portion. As illustrated, the inboard end of the spindle portion  56  terminates at a position inward of bearing  54 . A retention structure R secures the bearing  54  to the spindle  56 . It is the retention structure R and related components (coupler) to which the present invention is directed. The preferred and alternate embodiments thereof are described in detail hereafter. Adjacent the inner end of the spindle  56  is a CV joint that is a continuation of the axle  32  and they will be collectively hereafter referred to as axle  32 . 
     Axle  32  has a reduced configuration  33  that extends outwardly into and partially through the spindle/wheel hub  56 . 
     Reference is now made to FIG. 4 which is an enlarged view of the first version/embodiment of the invention. As shown, the inner diameter at the inner end of the spindle  56  is increased and provided with splines  58 . The extreme inboard end  61  is roll formed against the bearing  54  in a controlled manner to achieve the desired preload and to also maintain that preload. 
     A coupler  60  is spline fit to the inner diameter splines  58  of spindle  56 . A lock ring  59  secures the coupler  60  at the desired position. As shown, the inboard end of the coupler  60  wraps around the end  61  of the spindle and is provided with splines  62 . An adjoining portion of axle  32  is provided with matching splines  64 . The axle  32  is rotatably supported at end  33  by bearings  66  and  68  to allow rotation of the axle  32  relative to the coupler  60  and spindle  56 . 
     A clutch ring  68  slidably engages the splines  62 ,  64  of the coupler  60  and axle  32 . A pneumatic actuator  70  mounted to the knuckle  48  and connected to a media source (not shown) selectively slides the clutch ring  68  along the splines  62 ,  64  to engage one only of the axle and coupler (for disengagement) or to engage both the axle and coupler as shown (for engagement). As shown in FIG. 4 a , the mating of spindle  56  and coupler  60  via splines  58  may preferably be augmented by provision of mated non-splined surfaces  55 ,  59  to assure desired fit and centering of bearings  66 ,  68 . 
     Version 2 
     A second embodiment of the invention is illustrated in FIG.  5 . In this embodiment, the bearing inner race  54   a  is provided with inner splines  72  for splined engagement with the spindle  56   a , and outer splines  74  for splined engagement with clutch ring  68 . The spindle end  61   a  is roll formed as illustrated to secure the bearing on the spindle while providing and maintaining the desired preload. 
     A portion of axle  32   a  adjacent the spline  74  on inner race  54   a  is provided with matching splines for engagement by clutch ring  68 . 
     Version 3 
     A third embodiment of the invention is illustrated in FIG.  6 . The bearing inner race  54   b  is provided with screw threads  76  mated to screw threads  78  on the spindle  56   b . A locking device, e.g., lock ring  80 , locks the inner race  54   b  onto spindle  56   b  to retain a preload provided by the inner race being screwed onto the spindle. The spindle  56   b  extends beyond the lock ring  80  and provides splines  82  for engagement with clutch ring  68 . Splines  84  of axle  32   b  are matched with splines  82  on the spindle to allow selective and sliding engagement with the clutch ring  68  and engagement/disengagement of the axle  32   b  with the spindle  56   b  and thus the wheel hub. 
     Version 4 
     FIG. 7 illustrates a fourth embodiment of the invention. Spindle  56   c  is provided with an inboard end that is formed into an inwardly turned lip  61   c  having a dog lug engagement feature  86  (shown in dash lines). A coupler  60   c  having splines  62   c  (for engagement by a clutch ring) is roll formed at inner end  88  and behind lip  61   c  following preloading of the coupler against the bearing  54   c.    
     Version 5 
     FIG. 8 illustrates a fifth embodiment of the invention. Spindle  56   d  is provided with a slot having angled outboard side  90  and splines  92  at end  61   d . A coupler  60   d  is spline fit to the splines  92  and a retention ring  94  is pressed into the slot against side  90  to urge the coupler forward and thereby produce the preload on the bearing  54   d  and to retain that preload. FIG. 8A illustrates the same configuration with the retention ring being a split ring  94 ′ and a band  95  retaining the split ring. The band may be assembled, formed or interference fit. 
     Version 6 
     FIG. 9 illustrates a sixth embodiment of the invention. Spindle  56   e  is provided with a circumferential groove  96 , a portion of which has splines  97 . A coupler  60   e  is designed to slide over the end of the spindle and is then formed to match the splines  97  and to fit the smaller diameter of groove  96 . In the process, the coupler is pressed axially against the bearing to preload the bearing and lock the bearing in place. External splines  98  are subsequently formed into the coupler for engagement by the clutch ring. 
     Version 7 
     FIG. 10 illustrates a seventh embodiment of the invention. 
     The spindle  56   f  is provided with fingers or dogs  100 . Coupler  60   f  has mated fingers  102  that interlock with the fingers of the spindle (See FIG. 10 a ) and the protruding end  104  of the fingers  102  are then flattened in the manner of a rivet to secure the coupler and in the process preload the bearing  54 . 
     Version 8 
     FIG. 11 illustrates an eighth embodiment of the invention. The spindle  56   g  is provided with splines  106  and a coupler  60   g  having mated splines  108  is slid onto the splines and is compressed against the bearing  54 . A space between splines  106 ,  108  is filled with molten metal  110  to lock the coupler to the spindle and retain the preload against the bearing. 
     Version 9 
     FIG. 12 illustrates a ninth embodiment of the invention. The spindle  56  is configured at end  61   h  to mate with the configuration of coupler  60   h . The positioning of the bearing  54  is such that with the coupler abutted against the end  61   h , the bearing is desirably preloaded. Coupler  60   h  is then spin welded (friction welded) to the end  61   h . FIG. 12 a  shows a variation of the same embodiment. FIG. 12 b  is also a variation of the same embodiment. Here the coupler is slid onto the spindle end and the configuration of the coupler  60   h ″ provides a slot  112  in which a separate ring  114  is positioned and spin welded. The version of FIG. 12 b  permits the use of a spline fit as indicated by reference  113 . 
     Version 10 
     FIGS. 13,  13   a  and  13   b  are similar to FIGS. 12 a  and  12   b . The coupler  60   i ,  60   i ′,  60   i ″ is configured to match the ends  61   i ,  61   i ′ and  61   i ″ of the spindle  56  and the spindle and coupler are welded together following preload, as indicated by weld joints  116 . The coupler may also be spline fit as indicated at  117  in FIG.  13 . Also, a relief space  119  is exaggerated to demonstrate that the coupler  60   i  is abutted/compressed against race  54 . 
     Version 11 
     FIG. 14 illustrates an eleventh embodiment of the invention. A coupler  60   j  is spline fit to the spindle  56   j . The inner diameter  118  of the spindle end  61   j  is provided with screw threads with mated screw threads provided on retainer  120 . A lock washer  122  is fitted between the retainer  120  and coupler  60   j . A washer suitable for this purpose is disclosed in U.S. Pat. Nos. 5,772,373 and 5,618,143. 
     FIG. 14 a  shows the concept of FIG. 14 but applied to the outboard end of spindle  36   j′.    
     Version 12 
     FIGS. 15 and 15 a  illustrate a twelfth embodiment of the invention. A coupler  60   k  is mounted to spindle  56   k . End  61   k  is roll formed against the coupler  60   k  to provide the desired preload on bearing  54 . Coupler  60   k  is engaged by the clutch ring  68  to provide driving engagement between the axle  32  and the spindle/wheel hub extension  56   k . To insure driving engagement as between the coupler and spindle  56   k , the coupler and spindle have mated polygonal configurations  124 ,  126  as illustrated in FIG.  15 A. Whereas a hexagonal configuration is shown, other polygonal shapes will be equally satisfactory and including other interlocking shapes such as a double D shape. 
     FIGS. 16 and 16 a  illustrate a final and thirteenth embodiment of the invention. Here the spindle end  61   m  is provided with an outer diameter  128  that is configured to have a larger diameter than that of coupler  60   m  which is force fit onto the end  61   m , e.g., by heating the coupler relative to the spindle and forcing the coupler onto the spindle and against the bearing  54  so that when cooled the coupler incurs a tight and secure fit to the spindle. The outer diameter  128  may also be provided with a negative angle to enhance the tight fit. FIG. 16 a  illustrates a variation to the force fit by press fitting a dowel  130  into aligned holes  132 ,  134  in the spindle and coupler, respectively. 
     The above embodiments provide a number of benefits that will be apparent to those skilled in the art. Whereas the embodiments and variations are numerous, they are not all encompassing and further variations will become obvious. Accordingly, the invention is not limited to the above disclosures but is determined by the definitions provided in the accompanying claims.