GB2136368A

GB2136368A - Independent Suspension for Motor Vehicles

Info

Publication number: GB2136368A
Application number: GB08404252A
Authority: GB
Inventors: Wolfgang Frentzel
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG
Current assignee: MAN AG
Priority date: 1983-02-18
Filing date: 1984-02-17
Publication date: 1984-09-19
Also published as: DE3305722C2; FR2541196A1; GB2136368B; GB8404252D0; FR2541196B1; DE3305722A1

Abstract

Independent suspension for a steerable wheel comprises upper and lower wishbones (1 and 2) each mounted on the vehicle body (5) to pivot about a longitudinal axis and each formed by a leaf-spring. The wishbones are flexurally rigidly connected to legs (31o, 31u) of a channel section which is split into two parts (3o and 3u) at approximately the center of its web (3). The web has a cut-out for passage of a drive shaft (10) and inserted between shaped ends of the parts (3o, 3u) are studs (23) held in by prestrees. A stub axle (7) carried at the outer ends of the wishbones by kingpins (8) is connected to the vehicle body (5) by a shock absorber arranged to move along the generatrix of a cone when the axle (7) undergoes steering motion. <IMAGE>

Description

SPECIFICATION A Single-wheel Suspension for Motor Vehicles This invention relates to a resilient suspension for steered and preferably driven wheels of motor vehicles having an upper and a lower wishbone, each taking the form of single-leaf spring, to guide the wheel.

DE--AA-3132628 discloses a single-wheel suspension which is light in weight, robust, reasonably economical to manufacture and simple in construction, the two wishbones being supported on the vehicle body or frame for pivotal movement about longitudinal vehicle axes and being flexurally rigidly connected near the pivotal axis to the ends of the exposed legs of a channel section which is arranged in the space intervening between the two wishbones such that its U-web extends in parallel to the pivotal axes of the wishbones and in an approximately vertical direction. That suspension can be of a much simpler design than conventional devices of the type while still economising constructional weight and cost, but it still needs optimising especially with regard to manufacturing cost.

According to the present invention there is provided an arrangement in which the channel section is split in two parts at approximately the center of its U-web.

Splitting the resilient elements, which consist of wishbones and channel sections, into two separate, normally practically equal components, serves to greatly economise manufacturing cost, for the reasons that, firstly the contour of the halved resilient element is much simplified and, secondly the quantity to be manufactured now rises to twice the number. Splitting it down into two separate parts is possible because no bending moment is transferred at the parting point of the two parts, but only a transverse force, which is achieved by the two components supporting one another at their free ends.

Preferably the free ends of the respective channel web half take the shape of claws and a cylindrical stud is inserted between the claws of the two ends, the studs being prevented from dropping out by an amount of prestress that is maintained over the entire travel. Viewed axially the stud is prevented by means of suitable stop collars from slipping out from the guide formed by the two claws of the channel web halves.

While in the arrangement that is disclosed in DE--AA-3132628, the lower wishbone is reinforced by means of a crossbar with a shock absorber hinged to each of its ends, a singlewheel suspension in which the present invention is embodied is further simplified by using only a single shock absorber hinged directly to that steering stub which is pivotally guided between the two wishbones.

In this arrangement the shock absorber is preferably arranged such that at any steering angle it forms the generatrix of a cone and accordingly will not extend when the steering angle is being changed.

The shock absorber accordingly is arranged in an area, in which the spring travel is especially great, which from the design affords advantages concerning the cooling of the shock absorber. The special advantage provided by the arrangement in which the present invention is embodied, however, is that the shock absorber is hinged to the exact point where jolts from the road will produce vibrations, which is the point forming the center of gravity of the wheel and the moving parts of the suspension. When the shock absorber is attached to one of the two wishbones, their inherent spring action must be considered in the damping design; whereas this need is eliminated by the arrangement of the shock absorber in the preferred embodiment of the present invention.

An embodiment of the present invention is described more fully in light of the accompanying drawings, in which Figure 1 is a sectional view and illustrates a wheel suspension in which the present invention is embodied; Figure 2 is a simplified view of the wheel suspension of Figure 1 taken at line Il-Il of Figure 1; and Figure 3 is a plan view of Figure 1.

The wheel suspension illustrated in Figure 1 for a driven steerable wheel essentially consists of an upper wishbone 1 and a lower wishbone 2, each taking the form of a single-leaf spring. The two wishbones 1 and 2 guiding the wheel are each attached to a respective pivotal shaft 4 which in turn is carried in a respective bearing 6 provided on the vehicle body 5. Near the pivotal shafts 4, the wishbones 1 and 2 are torsionally rigidly connected for torsional rigidity to the ends of exposed legs 310, 31 u of a channel section, the torsionally rigid connection being achieved in the illustrated embodiment such that the channel legs 310 and 31 u form a single piece with the respective wishbone 1 and 2. A torsionally rigid connection can naturally be achieved also by bolting, riveting or similar methods.The channel section is split into two parts by splitting its approximately vertical web 3, which extends in parallel with the pivotal shafts 4, approximately centrally such that an upper partial member 30 and a lower partial member 3u of the channel web 3 is formed. In its central area the channel web 3 has a cutout to permit passage of a wheel drive shaft 1 0 (cm. Figure 2). Inserted between the claw-shaped ends of the two partial members 30 and 3u of the channel web 3 are cylindrical bearing studs 23a, 23b which by means of a suitably designed prestress of the two partial members 30 and 3u of the channel web 3 are prevented from dropping out. Endwise slipping of the studs 23a, 23b is prevented by suitably designed collars.

A steering stub 7 with the corresponding kingpins 8 is carried in boxes 30 at the respective outer ends of the wishbones 1 and 2.

Figure 3 is plan view of the wheel suspension, where for clarity, elements identified by reference numerals previously discussed with reference to Figures 1 and 2, are omitted.

As it will become apparent, the steering stub 7 pivots about the two kingpins 8 (only one of which is shown in Figure 3) by means of swivel rods 40.

Also, the steering stub is extended, at its approximate horizontal center, by a lug perhaps taking the shape of a pin to which is hinged the lower end of a shock absorber 42, which at its upper end is hinged to the chassis through a pin 43.

The shock absorber 42 is arranged such that when the rods 40 are operated for steering, it moves along the generatrix of a cone when the steering stub 7 goes through a pivotal motion, so that is will not appreciably lengthen or shorten in operation.

Claims

1. A resilient suspension for steered and preferably driven wheels of motor vehicles, having an upper and a lower wishbone in the form of a single-leaf spring to guide the wheel, in which the two wish bones are supported on the vehicle body for pivotal movement about longitudinal axes of the vehicle and are flexurally rigidly connected near this supporting point by the ends to the exposed legs of a channel section, and in which the channel section is arranged in the space between the two wishbones such that its channel web extends in parallel with the pivotal axes of the wishbones and in an approximately vertical direction, wherein the channel section is split in two parts at approximately the center of its web.

2. A wheel suspension according to Claim 1, wherein the free ends of the respective half-web take the shape of claws and a cylindrical stud is inserted between the claws of the two ends, the stud being prevented from falling out by a prestress maintained over the entire travel.

3. A wheel suspension according to Claim 1 or Claim 2, wherein one cylindrical stud is provided for the two free ends of channel web portions on either side of a cutout in the web of the channel section.

4. A wheel suspension according to any one of Claims 1 to 3, in which a steering stub is pivotally guided between the two wishbones and a shock absorber is hinged to the chassis and the suspension, wherein the shock absorber is hinged to the steering stub.

5. A resilient suspension for a steered, and preferably driven wheel of a motor vehicle substantially as described hereinbefore with - reference to the accompanying drawings.

6. A resilient suspension according to Claim 5, and as shown in the accompanying drawings.

7. Any other novel feature or combination disclosed hereinbefore or shown in the accompanying drawings.