Abstract:
An integrated wheel disconnect system is provided, including, a mechanically actuated engagement interlock selector assembly. The engagement interlock selector assembly including a housing, an interlock mechanism disposed in the housing, a spring disposed in the housing, and an actuator assembly, arranged to displace the interlock mechanism towards or away from the spring. The engagement interlock selector assembly is operated by an actuator module, such as a pin, sliding along an external ramp on the interlock mechanism, the mechanism moving axially to selectively engage and disengage the wheel hub from the drive axle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-in-Part of U.S. Ser. No. 13/234,677 filed Sep. 16, 2011, which in turn claims the priority of U.S. 61/384,842 filed Sep. 21, 2010, the priority of both applications is hereby claimed and both applications are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Example aspects herein relate to an integrated wheel disconnect system for a vehicle, and more particularly, to a system which selectively connects or disconnects driving and driven components of the wheel disconnect system to render selected wheels passive or driven. 
     Four wheel drive vehicles often have either front or rear wheels that have selectively driven or non-driven modes which operate by selectively engaging or disengaging the wheels from an associated drive train. In these four wheel drive systems, typically, a transfer case, coupled to the vehicle transmission, is designed such that it can be engaged or disengaged from the drive train. The engagement of the transfer case with the drive train selectively supplies power to a set of wheels. Although efficiencies can be obtained by solely disengaging the transfer case when not needed, it is known in the art that disengaging the wheels from the drive train improves driving efficiencies dramatically. 
     Where a transfer case is selectively disengaged from the drive train and the associated wheel set remains engaged, losses may result from the wheels “back driving” the system and having to overcome the rotational moment of inertia of half shafts, axle carrier assemblies, pinion shafts, and associated frictional losses in bearings, seals and gears. Therefore, it is desirable to have a wheel disconnect system that works in concert with the transfer case, engaging when the transfer case is engaged and disengaging when the transfer case disengages. It should be recognized that such wheel end disconnect systems may be used on either the front or rear wheels, depending upon which wheel set has the primary drive function. 
     Prior art wheel end disconnect systems utilize a vacuum system in order to disengage the wheel spindle from the drivetrain. Typically, such systems include a spindle supported by bearings in a support coupled to a suspension member, having an outer end portion adapted to mount a wheel thereon, and an inner extending portion, disposed towards the center of the vehicle with a radially extending flange that has engaging elements formed, generally on an outer diameter, of the flange. A drive element adapted to rotate under power is mounted adjacent the flange, with an engaging element or clutch slideably mounted thereon, such that it can be selectively moved into and out of engagement with the spindle flange of the wheel. The engaging element or clutch requires an axial force, as previously described, provided by a vacuum system, to disengage from the wheel assembly. Generally, a spring is also provided, that urges the engaging clutch back into engagement once the vacuum has been removed. 
     An inherent limitation of such a system is that a separate vacuum system must be provided, with associated difficulties in scaling the system properly to provide constant negative pressure. 
     SUMMARY OF THE INVENTION 
     In one example embodiment, the system comprises a wheel hub rotatably mounted on a drive axle. A wheel bearing, including an integrally assembled wheel hub is mounted to a vehicle using a suspension member or knuckle arrangement known in the art, the wheel bearing comprising an inner ring, outer ring and rolling elements between the rings. In another embodiment, the wheel bearing may form a separate unitary assembly that is assembled onto an outer diameter of a wheel hub, and fixed onto the assembly by a variety of methods known in the art, including a press fit. An engagement ring with outer engagement elements is mounted on the wheel hub and fixed into position using a variety of methods, including, but not limited to, orbital forming of a wheel hub flange or a nut arrangement. The engagement ring may be fixed against a surface of the inner ring of the wheel bearing. 
     Engagement elements on the outer diameter of the drive axle are assembled adjacent to and coplanar with the engagement elements of the engagement ring. An engagement interlock selector assembly is mounted on the outer diameter of the drive axle, allowing selective engagement and disengagement of the wheel assembly to the drive axle by sliding an engagement selector element or ring between the engagement elements of the engagement ring fixed to the hub and the engagement elements of the drive axle. The engagement selector ring is selectively moved by actuating an external actuator pin into a ramp mechanism on the outer diameter of the engagement selector ring, the selector ring disengaging the wheel from the drive axle and compressing an associated spring in contact with the selector ring. When the actuator pin is removed, a spring within the engagement interlock selector assembly urges the engagement selector ring into its standard position, either engaging or disengaging the wheel from the drive axle. 
     A method for operating an integrated wheel end disconnect mechanism, such as described above, also is provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above mentioned and other features and advantages of the embodiments described herein, and the manner of attaining them, will become apparent and be better understood by reference to the following description of at least one example embodiment in conjunction with the accompanying drawings. A brief description of those drawings now follows. 
         FIG. 1  is an exploded view of the wheel end disconnect assembly or system, according to one example embodiment herein. 
         FIG. 2 . is a side view of the wheel end disconnect assembly of  FIG. 1 , in a non-exploded perspective. 
         FIG. 3  is a non-exploded perspective view of the wheel end disconnect assembly of  FIG. 1 . 
         FIG. 4  is a non-exploded front view of the wheel end disconnect assembly of  FIG. 1 . 
         FIG. 5  is a cross sectional view of the wheel end disconnect assembly, taken along line A-A of  FIG. 4 . 
         FIG. 6  is a cross sectional view of the wheel end disconnect assembly of  FIG. 1 , in a disengaged or two wheel drive mode. 
         FIG. 7  is a cross sectional view of the wheel end disconnect assembly of  FIG. 1  in an engaged or four wheel drive mode. 
         FIG. 8  is a cross sectional view of an engagement interlock selector assembly, which can form part of the assembly of  FIG. 1 . 
         FIG. 9  is a perspective view of an engagement selector ring, which can form part of the engagement interlock selector assembly of  FIG. 8 . 
         FIG. 10  is a perspective view of a spring, which can form part of the engagement interlock selector assembly of  FIG. 8 . 
         FIG. 11  is a perspective view of a selector housing, which can form part of the engagement interlock selector assembly of  FIG. 8 . 
         FIG. 12  is a perspective view of an engagement ring, which can form part of the assembly shown in  FIG. 1 . 
         FIG. 13  shows the engagement selector ring of  FIG. 9 , as viewed from a perspective looking down on a face thereof. 
         FIG. 14  shows the engagement selector ring of  FIG. 9 , as viewed from a perspective looking at a side thereof. 
         FIG. 15  shows the engagement selector ring of  FIG. 9 , as viewed from a perspective looking down on another face thereof, which is opposite to the face of  FIG. 13 . 
         FIG. 16  is an exploded assembly view of the engagement interlock selector assembly of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Identically labeled elements appearing in different ones of the figures refer to the same elements but may not be referenced in the description for all figures. The exemplification set out herein illustrates at least one embodiment, in at least one form, and such exemplification is not to be construed as limiting the scope of the claims in any manner. 
     Radial spatial descriptions refer to relative diametral positions. For example, the term “radially inwardly” refers to a direction taken from a diametral outer edge towards a central axis of the system or assembly. Conversely, axial spatial descriptions refer to relative axial positions. For example, the term “axially inwardly” refers to a direction taken from an outboard portion of the assembly or system (e.g. wheel bolts  11  in  FIG. 1 ) towards an inboard portion (e.g. drive axle  8  in  FIG. 1 ). 
       FIG. 1  shows an exploded view of a wheel end disconnect assembly  100  according to an example embodiment herein. Wheel end disconnect assembly  100  comprises wheel bearing  50  rotatably mountable to a vehicle, and rotatably mountable on drive axle shaft  34  of drive axle  8 , using outer hub shaft support bearing  12  and inner hub shaft support bearing  3  pressable into an inner diameter of hub  2 , and axle drive shaft  34  inserted through the inner diameter of bearings  12  and  3 . Referring to  FIG. 5 , wheel bearing  50 , in turn, comprises integrated outer ring  1 , having at least one outer race  22  on an inside diameter of outer ring  1 , inner ring  23  and hub  2 , including at least one inner race  24  on an outside diameter of inner ring  23  and hub  2 , and rolling elements  18  disposed between the at least one outer race  22  and the at least one inner race  24 . Although wheel bearing  50  is shown as an integrated assembly with hub  2  in  FIG. 5  (e.g. having a raceway  24  on an outer diameter of hub  2 , and rolling elements between raceway  24  of hub  2  and raceway  22  in outer ring  1 ), in other embodiments, wheel bearing  50  may form a unitary assembly, separate from and assembled onto hub  2 . In the example embodiment in which the wheel bearing forms a separate unitary assembly that is assembled onto an outer diameter of a wheel hub, the wheel bearing may be fixed onto the assembly by a variety of methods known in the art, including a press fit. 
     Prior to assembly of wheel bearing  50  with drive axle  8 , engagement ring  4  is assembled to a radially outer, axially inner surface  52  of hub  2  (see  FIG. 5 ), the assembly accomplished by at least one of a variety of methods known in the art, including without limitation, for example: press fitting, spline engagement or an external nut arrangement. In one embodiment, engagement ring  4  is assembled to hub  2  by slotting ring hub engagement elements  33  into hub ring engagement elements  32 , then forming retention element  21  against an inner surface of engagement ring  4 . Retention element  21 , in one example embodiment, is made by orbital forming an extended flange portion of hub  2  in a radially outward direction, such that the flange contacts the side face of engagement ring  4 , thus retaining engagement ring  4  against bearing inner ring  23  (see  FIG. 5 ). Engagement interlock selector assembly  30  can be mounted to a suspension member or knuckle (not shown) of a motor vehicle (not shown) and drive axle  8  can be inserted through the internal diameter of interlock selector assembly  30 . C-clip  13  and nut  14  are then assembled onto drive axle shaft  34 , and tightened against inner ring face  17  of outer hub shaft support bearing  12  (see  FIG. 5 ). Engagement interlock selector assembly  30 , in turn, comprises selector assembly housing  31 , actuator  5  assembled through a hole (not shown) in housing  31 , an engagement selector ring (also referred to as an interlock mechanism)  6  with inner engagement elements  44 , inserted into housing  31 , and spring  7  inserted in an opposite end of housing  31  from that in which selector ring  6  is inserted. In one embodiment, actuator  5  is a solenoid. Also shown in  FIG. 1  is bearing seal  19 . 
       FIG. 2  is a side view of wheel end disconnect assembly  100 , comprising drive axle  8 , inserted through engagement interlock assembly  30  and wheel bearing  50 . Outer ring  1 , outer bearing seal  20 , wheel hub  2  and wheel bolts  11  for assembling wheel bearing  50  to a wheel (not shown), are also shown. Also shown in  FIG. 2  are engagement interlock selector assembly  30  comprising selector assembly housing  31 , actuator  5  assembled through a hole (see  FIG. 11 ) in housing,  31 , and mounting tabs  10  for mounting selector assembly  30  to a suspension member or knuckle (not shown). 
       FIG. 3  is a perspective view of wheel end disconnect assembly  100 , comprising drive axle  8 , inserted through engagement interlock assembly  30  and wheel bearing  50 . Outer ring  1 , outer bearing seal  20 , wheel hub  2  and wheel bolts  11  of wheel bearing  50  are also shown. Engagement interlock selector assembly also is shown, including selector assembly housing  31 , actuator  5 , and mounting tabs  10 . 
       FIG. 4  is a front view of wheel end disconnect assembly  100 , showing wheel hub  2 , outer ring  1 , engagement interlock selector assembly  30 , wheel bolts  11 , and drive axle  8 , and a front part of drive axle shaft  34 . Engagement interlock selector assembly  30  is also shown, including, selector assembly housing  31 , actuator  5 , spring  7  and mounting tabs  10 . 
       FIG. 5  is a cross sectional view of wheel end disconnect assembly  100 , taken along line A-A of  FIG. 4 . Wheel bearing  50  is shown, comprising, integrated outer ring  1 , wheel hub  2 , rolling elements  18 , bearing inner ring  23 , outer bearing seal  20 , bearing seal  19  and wheel bolts  11 . In this example embodiment, engagement ring  4  abuts bearing inner ring  23 , and a protruding hub flange is formed radially outwardly to form retention element  21 . Inner hub shaft support bearing  3  and outer hub shaft support bearing  12  are pressed into an inner diameter of hub  2 . Engagement selector assembly  30  is mounted to a suspension member (not shown) using mounting tabs  10  (see  FIG. 3 ). Engagement selector assembly  30 , as described above, comprises actuator  5  (including actuator pin  15 ) inserted through a hole in housing  31 , engagement selector ring  6  inserted in one end of housing  31 , and spring  7  inserted in another inner end of housing  31 . Seal  16  is pressed into an inner recess of housing  31 . It should be noted that, in another embodiment, the locations of engagement selector ring  6  and spring  7  may be reversed. Drive axle  8  is then inserted into the inner diameter of hub  2 , and c-clip  13  and nut  14  are assembled onto the outer end of drive axle shaft  34 . An outer circumferential surface of drive axle  8  is co-planar with or lies in a similar radial position as an outer surface of engagement ring  4 , and an inner surface of interlock mechanism  6 , such that engagement elements  44  of interlock mechanism  6  may simultaneously mesh with engagement elements  40  of engagement ring  4  and engagement elements  9  of drive axle  8 , respectively. 
       FIG. 6  is a cross sectional view of wheel end disconnect assembly  100 , taken along line A-A of  FIG. 4 , showing assembly  100  in a two wheel drive or disconnected mode. The features shown are the same as those in  FIG. 5 . When the transfer case (not shown) is disconnected from the drivetrain (not shown), a signal from a central control unit (not shown) to actuator  5 , causes actuator pin  15  to extend radially inwardly into engagement with selector ring inner slot  41 . As a tire (not shown) in contact with the road turns, wheel not shown) and wheel hub  2  rotate, in turn, rotating engagement ring  4 , and through contact between engagement ring outer engagement elements  40  and engagement selector ring inner engagement elements  44 , rotates engagement selector ring  6 . As engagement selector ring  6  rotates, actuator pin  15  enters engagement selector ring ramp  43 , moving selector ring  6  axially inwardly as pin  15  slides along the surface ramp  43 , compressing spring  7  against an inner face  45  of selector housing  31 . As actuator pin  15  enters selector ring outer slot  42 , selector ring  6  moves further axially inwardly, further contacting and compressing spring  7 , completing its axial movement and disengaging wheel hub  2  from drive axle  8  by eliminating contact between engagement ring outer engagement elements  40  and selector ring inner engagement elements  44 , thus eliminating transmission of power from a wheel (not shown) to drive axle  8 . Pin  15  maintains selector ring  6  in its disengaged position, resisting the opposing axial force exerted by compressed spring  7  against selector ring  6 . 
       FIG. 7  is a cross sectional view of wheel end disconnect assembly  100 , taken along line A-A of  FIG. 4 , showing assembly  100  in a four wheel drive or connected mode. The features shown are the same as shown in  FIG. 5 . Initially, transfer case (not shown) re-connects with the drivetrain (not shown), in turn, causing drive axle  8  to rotate at a given speed. In this mode, a signal is sent from a central control unit (not shown) to actuator  5 , causing actuator pin  15  to retract radially outwardly. As pin  15  is retracted, spring  7  is allowed to expand, contacting a side face of selector ring  6  and pushing selector ring  6  axially outwardly, towards wheel hub  2 . Selector ring inner engagement elements  44  engage with co-planar engagement ring outer engagement elements  40 . As meshing of the engagement elements occurs, power is transmitted through drive axle engagement elements  9  meshed with selector ring engagement elements  44  and into outer engagement elements  40  of ring  4 , thus enabling driving of hub  2  and an associated wheel (not shown). 
       FIG. 8  shows a reversed cross sectional view of engagement interlock selector assembly  30 . Housing  31 , actuator  5 , actuator pin  15 , spring  7 , selector ring  6 , selector ring inner slot  41 , outer slot  42 , ramp  43  and seal  16  are all shown and inner engagement elements  44  are represented. Also, retainer ring  48 , used to retain selector ring  6  within assembly  30  is shown. 
       FIGS. 9 to 12  show perspective views of individual components of interlock selector assembly  30 .  FIG. 9  is a perspective view of engagement selector ring  6 , and showing inner slot  41 , outer slot  42  and ramp  43  thereof. As shown in  FIG. 9 , the depth of the ramp  43  is greater than that the inner slot  41  and extends into the slot  41 . Also shown are inner engagement elements  44 .  FIG. 10  is a perspective view of spring  7 .  FIG. 11  is a perspective view of selector assembly housing  31 , showing actuator assembly hole  46  and mounting tabs  10 .  FIG. 12  is a perspective view of engagement ring  4 , showing ring hub engagement elements  33  and outer engagement elements  40 . 
       FIG. 13  shows a face of selector ring  6 , showing one or more grooves formed along an outer circumference of ring  6 , including inner slot  41 , outer slot  42  and ramp  43 .  FIG. 14  is a view of a side of selector ring  6 , showing selector ring inner engagement elements  44 .  FIG. 15  is a view of a face of ring  6 , wherein the face is an opposite face to that of  FIG. 13 . Ramp  43  provides a connection between slots  41  and  42 , and in one example is angled in such a way as to provide a path for pin  15 , when pin  15  is extended into engagement therein, to travel from inner slot  41  to outer slot  42 , while selector ring  6  is rotating. The ramp  43  extends into slot  41  as shown in  FIG. 9  and described above, such that when the selector ring  6  rotates, the pin  15  in inner slot  41  is guided into the ramp  43  and to the outer slot  42 . 
       FIG. 16  is an exploded assembly view of engagement interlock selector assembly  30  according to an example embodiment herein. Selector housing  31  is shown with mounting tabs  10  and actuator assembly hole  46 . Actuator  5  is insertable into actuator assembly hole  46 . Spring  7  and engagement selector ring  6  are insertable into housing  31  (e.g. such as at opposite ends of housing  31 ), and then retainer ring  48  can be inserted into housing  31  to retain selector ring  6  in housing  31 . Seal  16  can be inserted into housing  31  on an opposite end from that where retainer ring  48  is inserted, to prevent intrusion of debris and other contaminates into interlock selector assembly  30 . 
     An example of the manner in which engagement and disengagement of a wheel from a drivetrain is performed was described above in view of  FIGS. 6 and 7 . It is also contemplated in another example embodiment that spring  7  and selector ring  6  may be reversed in position relative to wheel hub  2 . In such a configuration, according to one example embodiment herein, engagement of pin  15  into selector ring slots  41  and/or  42  achieves engagement of wheel hub  2  with drive axle  8 , rather than disengagement. 
     Thus, according to an example embodiment herein, a wheel may be disconnected from a drive train using a mechanical actuating device, such as a pin and ramp assembly, not requiring separate vacuum system. 
     In the foregoing description, example embodiments are described. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto, without departing from the broader spirit and scope of the present invention. 
     In addition, it should be understood that the figures illustrated in the attachments, which highlight the functionality and advantages of the example embodiments, are presented for example purposes only. The architecture or construction of example embodiments described herein is sufficiently flexible and configurable, such that it may be utilized (and navigated) in ways other than that shown in the accompanying figures. 
     Although example embodiments have been described herein, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than as specifically described. Thus, the present example embodiments should be considered in all respects as illustrative and not restrictive. 
     LIST OF REFERENCE SYMBOLS 
     
         
           1  Integrated Outer Ring 
           2  Wheel Hub 
           3  Inner Hub Shaft Support Bearing 
           4  Engagement Ring 
           5  Actuator 
           6  Engagement Selector Ring or Interlock Mechanism 
           7  Spring 
           8  Drive Axle 
           9  Drive Axle Engagement Elements 
           10  Interlock Selector Assembly Mounting Tabs 
           11  Wheel Bolts 
           12  Outer Hub Shaft Support Bearing 
           13  C-Clip 
           14  Nut 
           15  Actuator Pin 
           16  Seal 
           17  Outer Hub Shaft Support Bearing Inner Ring Face 
           18  Rolling Elements 
           18  Bearing Seal 
           20  Outer Bearing Seal 
           21  Retention Element 
           22  Outer Race 
           23  Bearing inner Ring 
           24  Inner Race 
           30  Engagement interlock Selector Assembly 
           31  Selector Assembly Housing 
           32  Hub Ring Engagement Elements 
           33  Ring Hub Engagement Elements 
           34  Drive Axle Shaft 
           35  Knuckle Mounting Holes 
           40  Engagement Ring Outer Engagement Elements 
           41  Engagement Selector Ring Inner Slot 
           42  Engagement Selector Ring Outer Slot 
           43  Engagement Selector Ring Ramp 
           44  Engagement Selector Ring Inner Engagement Elements 
           45  Housing Spring Inner Face 
           46  Actuator Assembly Hole 
           48  Retainer Ring 
           50  Wheel Bearing 
           51  Wheel Bearing Inner Diameter 
           52  Hub Inner Surface 
           100  Wheel End Disconnect Assembly