Abstract:
An alignment adjuster for wheel alignment of a motor vehicle is provided. The alignment adjuster includes a shaft that is moveable within an elongated slot. The adjustable member in the preferred embodiment is a lower control arm and is attached via bushing to the shaft. The shaft includes a pinion gear that operatively contacts a rack element that is disposed near the elongated slot. Rotation of the shaft will initiate lateral movement of the shaft in the elongated slot.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates in general to motor vehicles. More particularly, the present invention relates to a mechanism for adjusting the camber and caster of the wheels of a motor vehicle. More specifically, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, the present invention relates to an adjustment mechanism that provides controlling movement to the lower control arm of a vehicle. 
     2. Discussion 
     Proper alignment of the vehicle&#39;s wheels are essential for a comfortable ride, ease of steering, extended tire life, and reduced road noise and vibration. Many alignment angles have been defined to assist in properly designing and aligning the wheels of a vehicle. Caster is the angle of the steering axis of a wheel from its vertical viewed from a lateral side of the vehicle. Camber is the angle of the wheel from its vertical viewed from the front of the vehicle. 
     The camber and caster of a vehicle can change over time as the vehicle wears and absorbs shocks and vibrations. Manufacturers, therefore, design vehicles to provide a means for adjusting the camber and caster. An effective method of providing such an adjustment mechanism is illustrated on the 2000 Toyota Tundra. This vehicle provides an adjustment mechanism where the lower control arm is attached to the vehicle frame. The adjustment mechanism includes an off-center cam that carries the bushing that attaches the lower control arm to the frame. The off-center cam can be rotated to move the lower control arm inboard and outboard laterally which affects the cam and caster of the wheel. Other prior art systems also include an off-center cam that provides for the adjustment, however, the amount of lateral movement is dependent upon the size of the off-center cam. This creates packaging concerns that may adversely affect surrounding components in an undesirable way. There is, therefore, a desire to provide a camber caster adjustment system that provide the necessary amount of lateral movement in a more compact design. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is the principal objective of the present invention to provide an alignment adjuster that provides adequate lateral adjustment. 
     It is another objective of the present invention to provide an alignment adjuster that is compact in design to alleviate packaging concerns. 
     In one form, the present invention concerns an alignment adjuster for a motor vehicle. The alignment adjuster includes a shaft that is moveable within an elongated slot. The adjustable member in the preferred embodiment is a lower control arm and is attached via bushing to the shaft. The shaft includes a pinion gear that operatively contacts a rack element that is disposed near the elongated slot. Rotation of the shaft will initiate lateral movement of the shaft in the elongated slot due to the rack element and pinion gear interaction. 
     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from a reading of the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings, which form an integral part of the specification, are to be read in conjunction therewith, and like reference numerals are employed to designate identical components in various views. 
     FIG. 1 is a perspective view of the front steering and suspension system of a motor vehicle including the vehicle left hand side lower control arm and illustrating the alignment adjuster of the present invention. 
     FIG. 2 is an exploded view of the alignment adjuster of the present invention. 
     FIG. 3 is an assembled view of the alignment adjuster of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An alignment adjuster for a motor vehicle is provided. In the following description, numerous specific details are set forth in order to provide a more comprehensive description of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without these specific details. In other instances, specific details of well-known features have not been described so as not to obscure the present invention. 
     Referring now to the drawings, FIG. 1 illustrates a front steering and suspension system  10  of a motor vehicle. System  10  includes a lower control arm  12  that is adapted to provide a support link for a wheel (not shown) to a vehicle frame  14 . Lower control arm  12  is pivotally attached to frame  14  at a front bushing  16  and a rear bushing  18 . Vertical movements of the associated wheel causes lower control arm  12  to pivot about an axis formed through front bushing  16  and rear bushing  18 . 
     Front bushing  16  of lower control arm  12  is attached to frame  14  through an alignment adjuster, specifically in the preferred embodiment a camber/caster adjuster  20 . The camber/caster adjusted  20  interconnects to the vehicle frame  14  and the adjustable member, which is the lower control arm  12  in the preferred embodiment. Camber/caster adjuster  20  is secured to a bracket  22  that is fixedly secured to vehicle frame  14 . It should be appreciated that rear bushing  18  is attached to frame  14  in a similar manner. Both front bushing  16  and rear bushing  18  can be adjusted independently in the inboard and outboard lateral direction, this adjustment promotes camber and caster changes in the wheel. 
     Turning now to FIG. 2, an exploded view of the camber/caster adjuster  20  of the present invention is illustrated. Bracket  22  is adapted to be fixedly secured to the vehicle frame at a first end  21  and pivotally secured to the lower control arm at a second end  23 . The second end  23  includes two opposing side walls  25  and  27  that are disposed to receive bushing  16  or  18  of the lower control arm  12  therebetween. The distance D between  20  side walls is slightly larger than the width  30  of bushing  16 . Although only bushing will be subsequently described in detail, it should be appreciated that bushing  18  and its associated camber/caster adjuster are substantially similar to that described herein. It should also be appreciated that, although not shown FIG. 2, lower control arm  12  is coupled to bushings  16 ,  18  preferably by providing a bore in which a bushing is inserted into. 
     Bracket  22  also includes a first slot  24  formed in side wall  25  and a second slot  26  formed in side wall  27 . Slots  24  and  26  extend in the lateral direction and are formed in second end  23  of bracket  22 . Disposed above first slot  24  is a first rack element  32  secured to the outer surface  33  of side wall  25 . Although not shown, a similar rack element is disposed above second slot  26 . 
     The camber/caster adjuster  20  includes a hollow shaft  40  that includes a second pinion gear  42  on its primary end  44  and a locking tab device  46  on its secondary end  48 . Locking tab device  46  cooperates with a hollow hex  50  that includes a first pinion gear  52  on a first end  54  thereof. The locking tab  46  cooperates with a mating portion on hollow hex  50  to prevent rotational movement therebetween and also appropriately lines up the first and second pinion gears  42  and  52 . Locking tab device  46  and mating portion are preferably formed by a semicircular portion  43  and a plurality of flat surfaces  45  to ensure proper rotational alignment and to prevent rotational movement therebetween. Shaft  40  is inserted through slot  26  and though an opening  56  formed in bushing  16  and also through slot  24 . Locking tab  46  of the second end  48  then mates with hollow hex  50 . It should be appreciated that with this arrangement as previously described, the first and second pinion gears  52  and  42  are operatively disposed in contact with the first ( 32 ) and second rack elements respectively. 
     Hollow hex  50  includes a hexongally shaped adjustment portion  60 . Hexongally shaped adjustment portion  60  is adapted to receive a wrench or similar tool to provide a rotational force to both the hollow hex  50  and the hollow shaft  40 . Rotational force causes the hex  50  and shaft  40  to move laterally because of the rack and pinion relationship with the bracket  22 . 
     Hollow shaft  40  has an opening  62  formed therethrough and hollow hex  50  also has a similar opening  64  formed therethough. The openings  62  and  64  are adapted to receive bolt  70  therethrough. The end portion  72  of bolt  70  is larger than opening  62  and therefore establishes a position of bolt  70 . Bolt  70  is positioned though the hollow shaft  40  and hollow hex  50  and the bolt&#39;s front portion  74  extends therethrough to cooperate with a mating nut  76  that can be tightened to hold the hollow hex  50  and hollow shaft  40  in a specific position. Consequently, bushing  16  is also held a specific position when the nut  76  is tightened to bolt  70 . 
     FIG. 3 illustrates an assembled view of the camber/caster adjuster  20 . To adjust the camber/caster, mating nut  76  is first loosened. Then hollow shaft  40  and hollow hex  50  are rotated, which causes the entire apparatus to move laterally depending on the direction of rotation. This lateral movement of bushing  16  affects the camber and caster of the wheel. It should be appreciated that the front bushing  16  and rear bushing  18  can both be adjusted with provides the necessary dimension to effectively adjust the alignment. When adjustment is complete, bolt  70  and nut  76  are tightened to once again hold hollow hex  50  and hollow shaft  40  in a specific position. 
     The foregoing description constitutes the preferred embodiments devised by the inventors for practicing the invention. It is apparent, however, that the invention is susceptible to modification, variation and change that will be obvious to those skilled in the art. Inasmuch as the foregoing description is intended to enable one skilled in the pertinent art to practice the invention, it should not be construed to be limited thereby but should be construed to include such aforementioned obvious variations and be limited only by the proper scope or fair meaning of the accompanying claims.