AU722786B2

AU722786B2 - Adjustable pivot for a motor vehicle suspension arm

Info

Publication number: AU722786B2
Application number: AU43683/97A
Authority: AU
Inventors: Kevin Joseph Mcintyre
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-02-28
Filing date: 1997-11-03
Publication date: 2000-08-10
Anticipated expiration: 2016-08-28
Also published as: AU4368397A

Description

'fI -1- P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Adjustable Pivot for a Motor Vehicle Suspension Arm o The following statement is a full description of this invention, including the best method of performing it known to me: GH REF: P20642K/JDF:RS -2 This invention relates to an adjustable pivot for a motor vehicle suspension arm.

The suspension of many modern motor vehicles and in particular motor cars provide for independently sprung wheels supported and aligned by suspension arms which are secured to the body or the chassis of the motor vehicle by way of pivoting bushes at the inner ends of the arms.

By way of example only the arms may comprise the upper or lower wishbones of a wishbone-type suspension, or the trailing or semi-trailing arms of an independent rear suspension but may also be pivoting arms incorporated in many other types of motor vehicle suspension.

It is highly desirable to make' provision for adjustment of the pivot point by which -the suspension is mounted to the vehicle chassis so as to provide adjustment for the camber, castor and/or toe adjustment in the motor vehicle suspension. The orientation of the wheel supported by the suspension can easily go out of alignment through wear, altering vehicle suspension 20 height through modifications or consistent loads carried by the vehicle, or the striking of the vehicle wheel against a curb or other obstruction. This can cause the angle of the wheel relative to the chassis of the motor vehicle to be affected, resulting in increased tyre wear.

The suspension in many motor vehicles however does not provide any adjustment of the pivot points and therefore no simple method of adjusting the camber, castor and/or toe angle of the vehicle wheel alignment.

Furthermore, there are many problems in attempting to provide an adjustable pivot for a motor vehicle suspension arm, in particular because the pivot is often located in a confined space in the motor vehicle with difficult accessibility making many commonly used methods of providing adjustable locations for pivot points difficult to implement. This problem is compounded due to the accuracy which is necessary in adjustment of thQ suspension and in particular in the difficulty of adjusting a motor vehicle suspension accurately when the S:20642K/419 3 chassis is jacked up, i.e. when there is no load on the suspension members. It is therefore an advantage to be able to provide an adjustable pivot which will enable adjustment to be simply and easily carried out while the load of the vehicle is fully upon the vehicle suspension, without the necessity of having to raise the vehicle which will generally cause suspension geometry change.

It is also desirable to provide an adjustable pivot for a motor vehicle suspension without having to structurally alter the suspension mount points by labour intensive welding, oversize boring, slotting, or by having to provide special tools for adjustment of the pivot point.

The present invention therefore provides an 15 adjustable pivot for a motor vehicle suspension arm of the type having a pivoting mounting to the vehicle chassis by way of a bearing tube containing a thick walled elastomeric bush and a bolt passing through the middle of the elastomeric bush, the bolt being supported 20 at either end by suitable flanges on either the vehicle chassis or the suspension arm; the adjustable pivot comprising an elastomeric bush adapted to fit within the bearing tube, a cylindrical plug housed within the elastomeric bush so as to be rotatable relative to the tube, the plug having a hole therethrough parallel to the axis of the tube but off-set therefrom, and a bolt adapted to pass through the hole while being restrained from rotating relative to the plug, the ends of the plug being adapted to abut flanges in either the suspension arm or the chassis, the flanges incorporating mounting holes for the bolt such that when the bolt is passed through the mounting holes in the flanges with the plug, elastomeric bush and bearing tube located therebetween, a nut may be tightened on the bolt causing the flanges to bear against the ends of the plug and prevent rotation of the plug relative to the flanges, Preferably the bolt is restrained from rotating relative to the plug by an elongate flat section S:20642K/419 4 extending the length of the bolt, causing the bolt to have a substantially shaped cross-section, and a corresponding flat in the off-set hole in the plug.

Alternatively the locating means may comprise splines on the bolt adapted to engage the off-set hole through the plug or any other equivalent preventing relative rotation of the bolt relative to the plug once the bolt has been axially engaged in the hole in the plug.

Preferably the cylindrical plug has orthogonal ends adapted to bear against adjacent faces of the flanges and wherein the plug ends are provided with an embossed pattern adapted to cause deformation ot and engagement with the faces of the flanges upon tightening of the nut on the bolt.

In one form of the invention the axis of the plug is parallel to but off-set from the axis of the elastomeric bush, and wherein the plug is restrained from rotating relative to: the elastomeric bush and the elastomeric bush isable to rotate relative to the bearing tube.

Preferably the elastomeric bush is provided in two cylindrical halves, each cylindrical half having a flange at one end and being adapted to be inserted into opposite ends of the bearing tube affixed to the suspension arms until the flanges abut the ends of the tubes with the distal ends of the bush halves contacting, or nearly contacting each other within the bearing tube.

Notwithstanding any other forms that may fall within its scope, one preferred form of the invention will now be described by way of example only with reference to the accompanying drawings, in which:- Fig. 1 is an exploded perspective view of a semitrailing arm independent rear suspension for a motor vehicle incorporating an adjustable pivot according to the invention; Fig. 2 is an end view to an enlarged scale of the plug forming part of the adjustable pivot shown in Fig.

1; S:20642K/419 Fig. 3 is a perspective view of a wishbone-type front suspension for a motor vehicle; Fig. 4 is a perspective view to an enlarged scale of the (prior art) conventional bearing tube pivot used in the suspension of Fig. 3; Fig. 5 is a similar view to Fig. 4 showing a replacement adjustable pivot according to the invention; and Fig. 6 is a side view of the pivot shown in Fig. with the mounting bolt and nut shown exploded for clarity.

One preferred form of the *invention will be 7 described with reference to Fig. 1 and Pig. 2 showing a semi-trailing arm 2 of an independent- rear suspension arranged to be engaged with a chassis rail 1 by way of pairs of flanges 11 attached to and extending from the chassis rail i. It will however be understood that the adjustable pivot can also be incorporated into other forms of motor vehicle suspension such as the inner 20 mounts for wishbones, trailing arms, etc. An adjustable

I

pivot for a wishbone front suspension will be described later with reference to Figs. 3 to 6.

The semi-trailing arm 2 which is adapted to support the wheel bearing at its outer end (not shown) to locate a drive shaft 12 typically provided with power through a constant velocity joint 13 is normally provided in one rigid piece having forwardly extending arms 2A each terminating in a bearing tube 14 integral with or affixed to the arms 2A. In a conventional prior art nonadjustable suspension the bearing tubes 14 are each provided with a thick walled elastomeric bush such as that shown at 3 and the bearing tubes are located between the relevant pairs of flanges 11 so that a plain bolt (not shown) may be passed through holes 9 in the flanges 11 and through the centre hole 15 in the thick walled elastomeric bush before being secured by a nut so as tq pivotally mount the bearing tube 14 between the flanges 11 with a certain amount of "give" due to the resilience S:20642K/419 6 of the thick walled elastomeric bush 3.

In providing an adjustable pivot for such a motor vehicle suspension arm according to the invention, the thick walled elastomeric bush 3 is discarded and a new assembly provided and assembled as will now be described with reference to pivot point 16 only, although it will be appreciated that a similar adjustable mount can also be provided at pivot point 17, if necessary or desired.

In an adjustable pivot for a motor vehicle suspension arm according to the invention, a thin walled elastomeric bush 4 is inserted into the bearing tube 14.

This bush is typically provided in two halves as shown in Fig. 1, each half having a flange 4A at one end which abuts against the corresponding end 14A of the bearing 15 tube 14 when assembled, so that the distal ends 4B of the halves of the elastomeric bush 4, abut or nearly abut within the bearing tube 14.

A cylindrical plug 5 is provided adapted to be rotatingly housed within the thin walled elastomeric bush S 20 and having a length substantially the same as the distance between the inner faces of the flanges 11. As can be clearly seen in Fig. 2 the plug, which is typically formed of solid metal, has an off-set hole 6 therethrough parallel to the axis 18 of the plug but offset therefrom.

A bolt 7 is also provided adapted to pass through the hole 6 and also through aligned holes 9 in the flanges 11. The bolt is adapted to be engaged in the plug by locating means preventing rotation of the bolt relative to the plug. The locating means can be any form of known device such as splines or keyways but is preferably formed by machining a "flat" 7A along the length of the bolt as can be clearly seen in Fig. 1 so as to form a generally D-shaped cross-section and by forming the hole 6 through the plug to a corresponding D-shaped cross-section as can be clearly seen in Fig. 2.

The adjustable pivot is assembled by placing the two halves of the thin walled elastomeric bush 4 into the S:20642K/419 7 bearing tube 14, inserting the plug 5 into the thin walled elastomeric bush, and then offering up the suspension arm to the flanges 11 until the hole 6 aligns with the holes 9 in the flanges 11ii. The bolt 7 is then passed through one flange 9, through the hole 6 in the plug 5 and through the other flange 9 until the threaded portion of the bolt protrudes beyond the second flange 11 with the bolt head 8 against the outside face of the opposite flange. A nut 10 is then engaged with the thread portion of the bolt and run up against the outside face of the adjacent flange 11.

SOnce the adjustable pivot is loosely in place, the location of the axis of the bearing 'tube 14 may be Sadjusted relative to the axis of the holes 9 through the flanges 11 by rotating the bolt 7 using a spanner engaged .with bolt head 8, and thereby rotating the plug 5 within elastomeric bush 4. Because the axis of the hole 6 and therefore of the bolt 7 passing therethrough is off-set from the axis of the plug 6 and therefore of bearing tube 14, such rotation will cause the location of the bearing tube 14 to be varied relative to the chassis rail 1. In S"this manner the pivot point may be adjusted as desired by the operator to achieve the required camber, castor or toe characteristics of the supported wheel. Due to the nature of the adjustable pivot, this adjustment can take place while the full weight of the vehicle is upon the suspension, thus facilitating accurate wheel alignment.

Once the desired alignment has been achieved, the nut 10 is torqued-up :upon the thread of the bolt 7 to a desired torque setting sufficient to firmly grip the inner faces of the flanges 11 against the ends of the cylindrical plug 5, preventing further rotation of the plug and the bolt relative to the flanges 11 and therefore preventing the motor vehicle suspension from moving out of alignment.

To assist in retaining the alignment in the desired setting, the ends 19 of the cylindrical plug 5 are formed orthogonal to the axis 18 of the plug and are provided S:20642K/419 8 with an embossed pattern adapted to cause deformation of and engagement with the inner faces of the flanges 11 upon tightening of the nut 10 with the bolt 7. The embossed pattern may take any desired configuration but it has been found particularly effective to provide a number of raised dimples or dots 20 spaced around the orthogonal end 19 of the plug 5 as can be clearly seen in Fig. 2. When the nut 10 is tightened to a predetermined torque setting, the dimples 20 dig into the inner faces of the flanges 11 positively locating the plug 5 in the desired orientation preset by rotating the bolt head 8 and preventing the vehicle suspension from moving out of the desired alignment.

In a further form of the invention as shown in Figs.

3 to 6 the adjustable pivot can be adapted for use in a wishbone-type front suspension. The wishbone front suspension typically comprises an upper suspension arm 21 pivotally mounted to the vehicle chassis 23 by way of a pair of bushed pivots in locations 22 at the inner ends of the wishbone arm.

The lower part of the wishbone suspension is typically formed from suspension arms 24 and 25 pivotally mounted to chassis component 26 by way of a pivot axis 27. The upper and lower wishbones between them support a carrier 28 for the axle 29 on which the front wheel of the vehicle is mounted.

The conventional (prior art) pivot located at 22 is shown in more detail in Fig. 4 wherein it can be seen that the pivot comprises a bearing tube 30 mounted to the chassis of the vehicle by way of a mounting stud 31 which is secured in place by a nut and washer 32 (Fig. The bearing tube 30 contains a thick walled elastomeric bush 33 which may support a tube 34 acting as a mount for the pivot bolt which passes through the tube and parallel flanges 35 in the wishbone 21 where it is secured by a nut 36.

In this embodiment of the invention, as for the embodiment previously described with reference to Figs 1 S:20642K/419 9 and 2, the thick walled elastomeric bush 33 is replaced with an elastomeric bush 37 (Fig. 5) in which is mounted a cylindrical plug 38. As for the previous embodiment the plug 38 incorporates an off-set hole 39 through which the mounting bolt is passed and which is provided with means to restrain rotation of the bolt relative to the plug. In order to provide a greater degree of adjustment in the wishbone arm configuration, the elastomeric bush 37 may be provided with a mounting for the plug 38 which is off-set from the centre of the bush 37 and therefore from the axis of the bearing tube 30. When this configuration is utilised, the plug is located within the S"elastomeric bush so that it cannot rotat6 relative to the elastomeric bush, but the bush is allowed to rotate 15 relative to the bearing tube 30. In this manner when the bolt 40 is inserted through the hole 39 in the plug 38 to locate the pivot between flanges 35 as shown in Fig. 6, rotation of the bolt head 41 using a conventional spanner rotates not only the plug 38 but the entire elastomeric bush 37 causing a greater degree of movement of the bolt axis relative to the axis of the bearing tube 30 than is possible by rotation of the plug 38 alone.

In other aspects the operation of the configuration shown in Figs. 3, 5 and 6 is similar to that previously described for the semi-trailing arm suspension shown in Figs. 1 and 2 with the plug 38 being "locked" in position and restrained from rotation relative to the flanges by tightening the nut 42 on the end of bolt 40, once assembled, securely clamping the ends of the plug 38 between the flanges 35 and inhibiting further rotation once the required adjustment has been made.

It is a particular feature of the adjustable pivot according to the invention that there are no slotted adjustments held in place by frictional forces or other latitudes of movement of the pivot point which would be prone to moving out of adjustment in robust use of the motor vehicle. Furthermore the adjustment is easy to make using simple tools accessible to every motor S:20642K/419 10 mechanic and allowing easy adjustment of the suspension mounting point in confined places in the motor vehicle chassis.

As previously described it is of considerable advantage to be able to adjust the pivot point of the vehicle suspension while the weight of the vehicle is upon the suspension without the necessity of having to raise the vehicle which would otherwise cause suspension geometry change and necessitate several "trial and error" attempts at adjustment before the desired setting was able to be reached.

re. C oew *o S:20642K/419

Claims

2. An adjustable pivot for a motor vehicle suspension arm as claimed in claim 1, wherein the cylindrical plug has orthogonal ends adapted to bear against adjacent faces of the flanges, and wherein the plug ends are provided with an embossed pattern adapted to cause deformation of and engagement with the faces of the flanges upon tightening of the nut on the bolt.
3. An adjustable pivot for a motor vehicle suspension arm as claimed in either claim 1 or claim 2, wherein the bolt is restrained from rotating relative to the plug by an elongate flat section extending the length of the bolt, causing the bolt to have a substantially shaped cross-section, and a corresponding flat in the off-set hole in the plug. S:20642K/419 -12
4. An adjustable pivot for a motor vehicle suspension arm as claimed in either claim 1 or claim 2, wherein the bolt is restrained from rotating relative to the plug by splines on the bolt engaging the interior surface of the off-set hole through the plug. An adjustable pivot for a motor vehicle suspension arm as claimed in any one of the preceding claims, wherein the axis of the plug is parallel to but off-set from the axis of the elastomeric bush, and wherein the plug is restrained from rotating relative to the elastomeric bush and the elastomeric bush is able to rotate relative to the bearing tube.
6. An adjustable pivot for a motor vehicle suspension arm as claimed in any one of the preceding claims, 15 wherein the elastomeric bush is provided in two cylindrical halves, each cylindrical half having a flange at one end and being adapted to be inserted into opposite ends of the bearing tube affixed to the suspension arms until the flanges abut the ends of the tubes with the distal ends of the bush halves contacting, or nearly contacting each other within the bearing tube. DATED THIS THIRD DAY OF NOVEMBER 1997 KEVIN JOSEPH MCINTYRE BY HIS PATENT ATTORNEYS GRIFFITH HACK S:20642K/419