AU600558B2 - Method and means for altering wheel alignment geometry - Google Patents

Description

COMMONWEALTH OF AUSTRALI 0 5 5 8 Patent Act 1952 CO M P LE T E S P E C I F I C A T I 0 N (ORIGINAw) Class Int. Class Application Number Lodged PI 0605 2 March 1987 Complete Specification Lodged Accepted Published Lfo 1 a cndr u* i fr ;r2 t- 1 1 Priority: Related Art Name of Applicant Address of Applicant Actual Inventors Address for Service S NEWCASTLE TRUCK BUS) WHEEL ALIGNMENT PTY. LIMITED Cnr. Pendleoury Road Alhambra Avenue, Cardiff, New Soutn Wales, 2285 S NEIL WILLIAM THIRLWAY, Berkley Street, SPEERS POINT NSW 2284 and BRUCE GODFREY GATGENS, 26 Lindsay Avenue, VALENTINE NSW 2280 F.B. RICE CO., Patent Attorneys, 28A Montague Street, BALMAIN. 2041.

Complete Specification for the invention entitled: "METHOD AND MEANS FOR ALTERING WHEEL ALIGNMENT GEOMETRY" The following statement is a full description of this invention including the best method of performing it known to Us:- 11 1 ,J 2 The present invention relates to vehicle steering geometry and more particularly to means for readily altering wheel alignment geometry.

In vehicles having their front steering wheels mounted to a closed differential housing, as is common in 4WD vehicles, the camber and caster angles are not easy to alter when compared with the case of stub axles mounted directly to a suspension assembly. Typically, the camber and caster are pre-set and fixed during the manutecture ot the vehicle in that the stub axle carrier housing is pivotally pinned to the main axle housing by co-axial upper and lower pins mounted in respective tapered roller bearings in the main axle housing. These upper and lower pins being akin to a king-pin in a king-pin steering system.

.e present-iveft--l-&--is-ists in astern j e assembly comprising a rotationally adjustable cranked pin member anc a pair of self-aligning bearings said steering adjuster as mbly being fitted between an outer stub axle carrier housin and an inner axle housing in a closed knuckle steering system whereby one steering pin is mounted in a self- ligning bearing and another steering pin comprises said c anked pin member mounted in a self-aligning bearing id cranked pin member being adapted to adjust the po tion of the outer stub axle carrier housing relative to the inner axle housing so as to alter the camber and caste of the steering system.

The present invention also consists in a method of adjusting steering geometry in a osed knuckle steering system comprising fitting a rotatio lly adjustable cranked pin member between an outer s b axle carrier housing and an inner axle housing, said in member and another steering pin being mounted in self aligning bearings, said pin member adapted to adjust he position of Lthe nutr sth a1 rrir honinn- relat-i o the i 2a The present invention consists in a steering adjuster assembly comprising a rotationally adjustable cranked pin member and a pair of self-aligning bearings,said steering adjuster assembly being fitted between an outer stub axle carrier housing and an inner axle housing in a closed knuckle steering system whereby one steering pin is mounted in one of said pair of self-aligning bearings and another steering pin comprises said cranked pin member mounted in the other of said pair of a self-aligning bearings said cranked pin member being adapted to adjust the position of the outer stub axle carrier housing relative to the inner axle housing so as to alter the camber and caster of the steering system.

The present invention also consists in a method of adjusting steering geometry in a closed knuckle steering system comprising fitting a rotationally adjustable cranked pin member between an outer stub axle carrier housing and an inner axle housing, said pin member and another steering pin being mounted in self-aligning bearings, said pin member adapted to adjust the position of the outer stub axle carrier housing relative to the 3 inner axle housing so as to alter the camber and caster of the steering system.

In an embodiment of the present invention one of the upper and lower pins in the closed Knuckle steering system is replaced by cam arrangement or a cranked pin and the other pin is mounted in a self aligning nearing. The cranked pin preferably comprises a pin part fitted into self aligning bearing, housed in the spherical outer end of a main axle housing. A circular pin part, mounted in a offset or cranked fashion on a rotatable pin part, is adapted to fit into a complementary bearing recess in the opposite side of the spherical outer end of the main axle housing with the rotatable pin part passing through a complementary recess in a plate mounted on the stub axle housing.

The present invention will now be described by way of example with reference to the accompanying drawings, in which:- Fig. 1 is a schematic part sectional view through a steering/driving wheel drive assembly (as is common on, say, four wheel drive (4WD) vehicles) incorporating an adjuster assembly in accordance with an embodiment of the present invention; Fig. 2 is a larger scale view of the circled part II of Fig. 1 with minor additions and omissions; Fig. 3 is a perspective view of the cranked pin adjuster of the type employed in Figs. 1 and 2; and Fig. 4 is sectional view IV-IV of Fig. 3.

Referring to Fig. 1 which shows one half of a typical 4WD front differential and drive assembly comprising a differential housing 11 an axle 12 driving a stub axle 13 via a constant velocity joint 14. The caster and camber applied to stub axle 13 and hence a wheel mounted on studs 15 adjacent disc brake rotor 16 is set by fixing the relative positions between the stub axle 4 carrier housing 17 and axle housing 18 or its enclosed axle 12. This relationship is determined by the positioning of pins 19, 20 which pivotally couple together housings 17 and 18.

In the embodiment ot the present invention depicted in the drawings pins 19 and 20 are fitted into a self aligning bearings 21a and 21b and pin 20 is formed as a cranked pin 20 of the adjuster assembly 40 of Figs. 3 and 4. The offset of pin 20 relative to shaft 22 in adjuster assembly 40 enables the position of stub axle carrier housing 17 to be varied relative to axle nousing 18 with the movement of opposite pin 19 oeing compensated for by self-aligning bearing 21b. Stub axle housing 17 being connected to a steering mechanism (not shown) via top steering link 23.

The camber applied to housing 17 and hence stub axle 13 is variable by positioning cranked pin 20 so as to move housing 17 in the direction of arrows 24 relative to axle housing 18. Caster is adjustable by positioning pin 20 so as to move housing 17 in tore and aft directions or more correctly to rotate housing 17 relative to housing 18 about the axis of stub axle 13 to change the angle of the pivot axis between pins 19, 20 and the vertical; which angle corresponds to the caster.

As can be seen in Figs. 3, 4 the pin 20 is offset in the manner of a crank relative to the axis of shaft 22 so thet rotation of shaft 22 causes pin 20 to move in an orbital fashion about the axis of shaft 22. The adjustment of caster and camber being readily achieved by rotating shaft 22 via externally protruding boss 22' and locking the position of shaft 22 by means of a locking nut 22a or a locking pin (not shown).

To employ an arrangement of the present invention as an accessory in existing vehicles the adjuster assembly of Figs. 3 and 4 is fitted in place of the pre-existing lower c bearing pin between the stub axle carrier housing 17 and the axle housing 18 and the original taper bearings are replaced by self aligning bearings 21a and 21b which in this case are of the cup and cone type. Thereafter the camber and caster adjustments are carried out by rotation of the shaft 22 to locate pin 20 to the desired position.

As this adjustment takes place on the bottom self-aligning bearing 21a the resultant alteration of the axis is compensated for at the top by interaction between pin 19 and self aligning bearing 21b.

The cammed or crank adjuster of the embodiment is shown as having infinitely variable positioning but of course it could be provided with step-wise adjustments as will be readily appreciated by the addressee.

Claims (12)

1. A steering adjuster assembly comprising a rotationally adjustable cranked pin member and a pair of self-aligning bearings said steering adjuster assembly being fitted between an outer stub axle carrier housing and an inner axle housing in a closed knuckle steering system whereby one steering pin is mounted in one of said pair of self-aligning bearings and another steering pin comprises said cranked pin member mounted in the other of said pair of a self-aligning bearings said cranked pin member being adapted to adjust the position of the outer stub axle carrier housing relative to the inner axle housing so as to alter the camber and caster of the steering system.

2. A steering adjuster assembly in accordance with claim 1 wherein said cranked pin member is adjustable through infinitely variable positioning.

3. A steering adjuster assembly in accordance with Ai claim 1 wherein said cranked pin member is adjustable A, through step-wise variable positioning.

4. A steering adjuster assembly in accordance with any one of the preceding claims wherein said assembly includes a locking means for locking said cranked pin in a desired position.

A steering adjuster assembly in accordance with any one of the preceding claims wherein said self-aligning bearing is of a cup and cone type.

6. A method of adjusting steering geometry in a closed knuckle steering system comprising fitting a rotationally adjustable cranked pin member between an outer stub axle carrier housing and an inner axle housing, said pin member and another steering pin being mounted in self-aligning bearings, said pin member adapted to adjust the position of the outer stub axle carrier housing relative to the inner axle housing so as to alter the camber and caster of the steering system. I 7

7. A method of adjusting steering geometry in accordance with claim 6 wherein said cranked pin member is adjustable through infinitely variable positioning.

8. A method of adjusting steering geometry in accordance with claim 6 wherein said cranked pin member is adjustable through step-wise variable positioning.

9. A method of adjusting steering geometry in accordance with any one of claims 6 to 8 wherein said assembly includes a locking means for locking said cranked pin in a desired position.

A method of adjusting steering geometry in accordance with any one of claims 6 to 9 wherein said self-aligning bearing is of a cup and cone type.

11. A steering adjuster assembly substantially as hereinbefore described with reference to the drawings.

12. A method of adjusting steering geometry substantially as hereinbefore described with reference to the drawings. DATED this 31st day of May 1990 NEWCASTLE TRUCK BUS) 9HEEL ALIGNMENT PTY. LIMITED Patent Attorneys for the Applicant: F.B. RICE CO.