GB2191456A - Beam axle suspension with panhard rod and torsion bar - Google Patents

Abstract

A vehicle suspension comprises a Panhard rod (11) and a resilient elongate member (22) which restrains the body of the vehicle against rolling movement relative to a beam axle (10). The elongate member is pivotally connected at its ends to the vehicle body and to the axle respectively and at a position intermediate its ends to the Panhard rod, so that the member is subject to bending when roll occurs. <IMAGE>

Description

SPECIFICATION Vehicle suspension This invention relates to a vehicle suspension, comprising a beam axle extending transversely of the vehicle and restrained against movement transversely of the vehicle (i.e. along the length of the axle), relative to the vehicle structure, by a Panhard rod connected at a first end to the axle at a position adjacent to a first end thereof, the other end of the Panhard rod being connected to the vehicle structure adjacent the second end of the axle.Such a suspension will hereinafter be referred to as a suspension of the type specified, A known method of controlling roll of a vehicle body relative to a beam axle employs an anti-roll bar, which comprises a bar extending transversely of the vehicle, pivotally secured to the vehicle structure at two spaced positions, with end portions of the bar extending lengthwise of the vehicle and being pivotally connected to the axle at positions adjacent to the ends thereof. Relative roll between the vehicle body and the axle causes torsion in the transversely extending part of the bar, which acts to resist the rolling. However the arrangement is relatively bulky and has the disadvantage that the anti-roll bar must be accommodated and secured to the vehicle structure at a location spaced from the axle.

It is an object of this invention to provide a compact vehicle suspension wherein the vehicle body is restrained against rolling and lateral movement relative to an axle.

According to the invention we provide a vehicle suspension of the type specified including a resiliently bendable elongate member pivotally connected at a position intermediate its ends to the Panhard rod at a position intermediate the ends of the Panhard rod, a first end of the member being connected to the axle at a position adjacent to the second end thereof by means allowing relative movement therebetween pivotally and lengthwise of the axle, and the second end of the member being connected to the vehicle structure at a position adjacent to the first end of the axle by means allowing relative movement therebetween pivotally and transversely of the vehicle structure.

The arrangement is such that the elongate member does not hinder relative vertical movement between the axle and the vehicle structure but is effective to resist relative roll by resiliently deforming in the bending mode.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic perspective view of part of a vehicle suspension according to the invention; Figures 2-5 are schematic front views of a vehicle comprising the suspension shown in Figure 1, showing different operative positions thereof.

Referring to Figure 1 a vehicle suspension comprises a beam axle 10 extending tranversely of a vehicle body (not shown) and restrained against lateral movement relative to the body by means of a Panhard rod 11. The axle 10 carries at each of its first and second ends 12, 13 a respective bracket 14 to support a wheel and a channel member 15 to hold a leaf spring (not shown) by which means the body is supported relative to the axle 10. The vehicle suspension may be for the rear wheels of a front wheel drive vehicle.

A first end 16 of the Panhard rod 11 is pivotally connected to the axle 10 at a position 18 adjacent to the first end 12 of the axle, by a pivot 20 having its pivotal axis extending lengthwise of the vehicle. The other end 17 of the Panhard rod 11 is pivotally connected to a bracket 19 fixed to the vehicle body, at a position adjacent to the second end 13 of the axle 10, by a pivot 21 having its pivotal axis extending lengthwise of the vehicle.

A resilient elongate member 22 has at a first end 23 connected to a part 25 of the vehicle body, at a position adjacent to the first end 12 of the axle 10, and a second end 24 connected to the axle 10 at a position 26 adjacent to the second end 13 thereof by means of respective connections 27, 28. The connections 27, 28 comprise elastomeric bushes which allow relative pivotal movement about axes extending lengthwise of the vehicle and allow relative translational movement transversely of the vehicle body and lengthwise of the axle 10 respectively.

The elongate member 22 is pivotally connected, at a position between its ends 23, 24, to the Panhard rod 11 at a position between the rod's pivots 20, 21, by a central pivot 29, such that the member and rod are pivotable relative to one another about an axis extending lengthwise of the vehicle.

The parts 19, 25 of the vehicle body to which the Panhard rod 11 and the elongate member 22 are connected are disposed sym metricaliy, substantially equal distances from the longitudinal centre line of the vehicle as are the positions 18, 26 on the axle 10 at which the Panhard rod 11 and elongate member 22 are connected. The pivot 29 thus lies substantially on the vehicle centre line, although it will move in an arcuate path with movement of the Panhard rod.

The elongate member 22 may be made from spring steel or from composite fibre-reinforced plastics material.

The operation of the invention will now be described with reference to Figures 2 to 5 of the drawings.

Figure 2 illustrates a vehicle having a suspension according to the invention in a position wherein the body 30 is maintained in a level attitude relative to the axle 10 and in a raised position, for example when the body 30 is relatively lightly loaded. Figure 3 shows the vehicle shown in Figure 2 in a position wherein the body 30 is maintained in a level attitude relative to the axle 10 and in a lowered position, for example when the body 30 is relatively heavily loaded.

When the suspension moves from its raised to its lowered positions the first end 23 of the elongate member 22 moves transversely of the body, to the right as shown in Figure 3 from position 23a, and the second end 24 moves lengthwise of the axle 10, to the left from position 24a as shown in Figure 3 so that the elongate member is not deformed and does not hinder the movement. The relative lateral movement occurring between body and axle as a result of the use of a Panhard rod is somewhat exaggerated in Figures 2 and 3.

Figures 4 and 5 illustrate the vehicle in positions wherein the body 30 has rolled to the left and to the right respectively, for example during cornering.

When the body 30 rolls to the left as shown in Figure 4 the ends 23, 24 of the elongate member 22 can no longer remain in line with the central pivot 29 so the elongate member is elastically deformed so that its upper surface is concave. The deformed elongate member 22 therefore resists the rolling movement by resiliently urging the body 30 back into a level position, shown in Figures 2 and 3, so that it can return to its undeformed state.

When the body 30 rolls to the right as shown in Figure 5 the elongate member 22 is deformed in the opposite sense and resiliently urges the body 30 back into a level position.

Thus the elongate member 22 is operative to resist roll of the body 30 relative to the axle 10 but does not hinder relative vertical movement therebetween. Because the member 22 is mounted adjacent the axle, it is not necessary to provide in the vehicle for mounting of an anti-roll bar at a position away from the axle.

Although a particular example of a beam axle is above described, the invention is equally applicable to other types of beam axle, e.g. to a live axle supporting drivable wheels.

Further, the axle may be suspended relative to the vehicle structure by means other than leaf springs, e.g. by coil springs or springs of other configuration; and its path of permissible movement relative to the vehicle structure may be constrained by other linkages in addition to the Panhard rod.

Claims (4)

1. A vehicle suspension of the type specified including a resiliently bendable elongate member pivotally connected at a position intermediate its ends to the Panhard rod at a position intermediate the ends of the Panhard rod, a first end portion of the member being connected to the axle at a position adjacent to the second end thereof by means allowing relative movement therebetween pivotally and lengthwise of the axle, and the second end of the member being connected to the vehicle structure at a position adjacent to the first end of the axle by means allowing relative movement therebetween pivotally and transversely of the vehicle structure.

2. A vehicle suspension according to Claim 1 wherein the connecting means of the elongate member comprise elastomeric elements.

3. A vehicle suspension according to Claim 1 or Claim 2 wherein said pivotal connection between the Panhard rod and elongate member lies substantially on the longitudinal centre line of the vehicle.

4. A vehicle suspension substantially as hereinbefore described with reference to the accompanying drawings.