GB2341362A

GB2341362A - Vehicle suspension system

Info

Publication number: GB2341362A
Application number: GB9820391A
Authority: GB
Inventors: Peter John Walker
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-09-09
Filing date: 1998-09-19
Publication date: 2000-03-15
Anticipated expiration: 2018-09-19
Also published as: GB9819642D0; GB2341362B; GB9820391D0

Abstract

A vehicle suspension system has pivot axes of either the top or bottom arms which are movable laterally. In the described embodiment the upper arms 2,11 are connected to the chassis 1 by a pivot shaft assembly 6,9, allowing the pivot axes of the arms 2,11 to move laterally. The lateral movement is controlled by diagonal interconnecting links 5,8 between the pivot axes and the lower arms 3,7, to maintain optimum camber angles. In a further embodiment, in a strut and lower arm suspension system, the upper strut pivots move laterally and are connected to diagonally opposite lower arms.

Description

2341362 VEHICLE SUSPENSION SYSTEM This invention relates to a suspension

system for vehicles.

Dual arm (e.g. double-wishbone) suspension and strut & lower arm (e.g. Macpherson t strut) suspension are widely used. It is the norm for the geometry of both these vehicle suspension types to compensate for body roll when cornering, so maintaining an optimum tyre contact patch with the road - and thus optimum grip.

However with longitudinal load transfer (when acceleration and braking), this compensation for lost camber during cornering causes the adoption of an excess of camber while travelling in a straight fine, so reducing the tyre contact patch and, as a consequence, grip. Anti-squat and anti-dive systems have been used to control suspension movement arising from longitudinal load transfer, but these are only partially effective and introduce unwelcome side effiects which compromise performance.

For dual arm suspension, according to this invention there is provided a means of allowing the pivot axes of either the upper or lower suspension arms to move laterally and independently across the vehicle. There is also provided a means of interconnection between these laterally moveable pivot axes and their diagonally opposite, fixed pivot, suspension arm counterparts. This interconnection allows the Vertical movement of each fixed pivot arTn to be translated into a co-ordinated lateral movement of its diagonally linked moveable arm, so optimising the camber angle and tyre-to-road contact patch.

According to this invention, strut & lower arm suspension is provided for in a similar fashion. In this case there is provided a means of allowing the upper strut pivots to move laterally and independently across the vehicle and, in the same way, interconnection is provided between these moveable pivots and their diagonally opposite lower arms. Once again vertical movement of each arm is translated into a coordinated lateral movement of its diagonally inteiconnected upper strut pivot and, similarly, camber angle and tyre contact patch are optimised.

A specific embodiment of this invention wilI now be described by way of example with reference to the accompanying drawing. Here, Fig 1 is considered to be a diagrammatic representation of the rear view of the dual-arin, rear suspension system of a rear wheel driven vehicle. This invention is, however, equally applicable to front suspension designs as it is to rear suspension designs and to front wheel drive vehicles as it is to rear wheel drive vehicles.

When cornering (say to the right) the chassis (1) rolls to the outside of the bend, anticlockwise in this example, and the left hand suspension assembly moves up while the right hand suspension assembly moves down. As is normal with this type of suspension system, when the left hand top arm (2) pivots upwards, its geometry in relation to the left hand bottom arm (3) ensures an increase in negative camber (relative to the chassis) of the left hand wheel & tyre assembly (4), to compensate for chassis/body roll. With this invention, part of this camber compensation is achieved by the action of the interconnecting link (5) and its pivot shaft assembly (6) which translates the simultaneous downward movement of the right hand bottom arm (7) into an inward lateral movement of the left hand top arm (2).

Similarly, and in reverse fashion, the right hand interconnecting link (8) and pivot shaft assembly (9) contribute to the increase in positive camber (relative to the chassis) of the right hand wheel and tyre assembly (10), again to compensate for body/chassis roll.

An additional function of the interconnecting links (5&8) and pivot shaft assemblies (6&9) is to utilise the forces generated during cornering to reduce body/chassis roll.

When accelerating in a straight line, the elfects of longitudinal weight transfer compress the suspension on both sides. In a conventional suspension system of this type, this would lead to the adoption of negative camber on both wheels, reducing the tyre-to-road contact patch and therefore grip. With this invention, the upward movement of the two lower arms (3&7) acts via the interconnecting links (M5) and pivot shaft assemblies (9&6), to move the top arms (11&2) laterally outwards in compensation, away from the centreline of the car, so maintaining the optimum tyreto-road contact patch and therefore tractive grip. Sinfflarly, when braking, the movement of the two lower arms (3&7), now downwards, once again acts via the interconnecting links to reduce the adoption of unwanted camber (in this case positive) and thus once more optimise contact patch and grip.

The principles of operation of this invention, as applied to strut and lower arm suspension, are in all ways similar.

Claims

1. A dual-arm suspension system where either the pivot axes of both top or both bottom suspension arms are allowed to move laterally and independently from each other. Interconnections between these laterally moveable pivot axes and their diagonally opposite, fixed pivot suspension arm counterparts which translate the vertical movements of the fixed pivot arms into co-ordinated lateral movements of the moveable pivot arms, thus maintaining optimum camber angles and tyre-to-road contact.

2. A strut and lower arm suspension where the upper strut pivots are allowed to move laterally and independently from each other. Interconnections between these laterally moveable pivots and their diagonally opposite lower arms which translate the vertical movements of the arms into co-ordinated lateral movements of the upper strut pivots, thus maintaining optimum camber angles and tyre-to-road contact.

Amendments to the claims have been filed as follows 1. An independent suspension system where there is provided a means of allowing the camber angle of each wheel to be altered, independently, in response to an appropriate input derived from the movement of suspension components on the opposite side of the vehicle centreline - thus maintaining optimum camber angles, tyreto-road contact and grip.