GB2265867A - A vehicle chassis and suspension arrangement. - Google Patents

Abstract

The vehicle chassis comprises a chassis frame 10 having two spaced longitudinal side members 11 and may have two or more cross members extending between the two side members. The chassis also comprises an independent suspension system comprising a plurality of independent suspension units 13, each supporting a wheel hub 12 and each having upper and lower suspension arms 14, 15 connected between the chassis frame 11 and a respective wheel hub. The side members 11 of the chassis frame 10 extend between the upper and lower suspension arms 14, 15 of associated suspension units 13. In the case of driven hubs the drive shafts 20 preferably extend through respective apertures 21 in respective side members 11. Steering links for steerable hubs also preferably extend through apertures in the side members. <IMAGE>

Description

A VEHICLE CHASSIS This invention relates to a vehicle chassis, and more particularly, but not necessarily exclusively, to a vehicle chassis of the type which is formed separately from bodywork of the vehicle.

For a given ground clearance, there is often a requirement to minimise chassis height in order to improve vehicle stability (particularly important in off-the-road vehicles) and/or to provide a low loading deck (particularly important in some commercial vehicles such as refuse collection vehicles and brewery drays).

In rigid axle vehicles, the axle has of necessity to be mounted below the chassis frame and, in vehicles with an independent suspension, it has also been conventional to mount the suspension system below the chassis frame. This severely restricts the minimum height of the chassis which can be achieved for a given ground clearance.

The present invention seeks to provide a vehicle chassis which will enable the overall height of the chassis to be reduced for a given ground clearance.

The present invention provides a vehicle chassis comprising a chassis unit having two spaced side members extending in a direction parallel to the intended direction of travel of the vehicle, and a plurality of independent suspension units, each supporting a wheel hub and each having upper and lower suspension arms connected between the chassis unit and a respective wheel hub, wherein the side members of the chassis unit extend between the upper and lower suspension arms of associated suspension units, or lie at least substantially between the upper and lower suspension arms of associated suspension units when viewed from the side.

Preferably, the chassis unit is in the form of a chassis frame having, in addition to the two spaced side members, two or more cross members extending between the two side members.

Preferably, the chassis also includes two drive shafts connecting a differential gear to a pair of wheel hubs, one on each side of the chassis, the two drive shafts extending through respective apertures in respective side members of the chassis unit.

Preferably, steering links to steerable wheel hubs extend through apertures in the side members of the chassis unit.

At least one, and preferably each, of the upper and lower arms of each suspension unit may be in the form of a wishbone.

Each suspension unit may also comprise a coiled spring and a shock absorber.

The chassis may also comprise hydraulic antiroll units.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic end view of part of one embodiment of a vehicle chassis according to the present invention, and Figure 2 is a schematic side view of part of the vehicle chassis shown in Figure 1.

The vehicle chassis shown in the drawings is formed separately from the bodywork of the vehicle and is typically for use in commercial and off-the-road vehicles.

The chassis comprises a chassis frame 10 having two spaced, box section, side members 11 (only one of which is shown), which extend in a direction parallel to -the intended direction of travel of the vehicle, and two or more cross members 25 (only one of which is shown) extending between the two side members 11o Typically, the cross members 25 extend perpendicularly to the side members 11, but this is not essential.

The chassis also comprises a plurality of wheel hubs 12 and an independent suspension system comprising a plurality of independent suspension units 13 connecting respective wheel hubs 12 to the chassis frame lOo The chassis also includes a driving head including a casing 19 housing a differential gear unit (not shown). The casing 19 is conveniently supported on one of the cross members 25 by a rubber mounting (not shown), and is disposed between the two side members 11 Each independent suspension unit 13 comprises an upper suspension arm 14 and a lower suspension arm 15. The suspension arms 14 and 15 are connected either directly or indirectly at their inner ends to the chassis frame 10 for pivotal movement about axes parallel or substantially parallel to the intended direction of travel of the vehicle.Typically, both arms 14 and 15 are in the form of wishbones.

Each hub 12 has an associated disc brake -and also has an upwardly projecting member 16 rigid with the hub 12. The outer end of the upper suspension arm 14 is connected to the upper end of the member 16 by a ball and socket joint. The lower suspension arm 15 is connected to the hub 12 by a similar ball and socket joint.

Each independent suspension unit 13 also comprises at least one, and preferably two, coiled springs 17 and at least one, and preferably two, shock absorbers 18. The coiled springs 17 and the shock absorbers 18 are each connected between the lower suspension arm 15 of a respective suspension unit 13 and a bracket 27 secured to and generally upstanding from a respective side member 11 of the chassis frame 10.

In the example shown, the inner ends of the suspension arms are pivotally connected to lugs 26 secured to the casing 19 of the driving head and, in this arrangement, the side members 11 of the chassis frame 10 extend between the upper and lower suspension arms 14 and 15 of associated suspension units 13. This has the effect of reducing the overall height of the chassis for a given ground clearance, typically by about 350mm, resulting in improved vehicle stability and a reduction in the height of any loading deck which may be provided on the chassis. The inner ends of the suspension arms could however be connected to lugs secured to the side members 11.In this case, the side members 11 may not strictly extend between the upper and lower suspension arms of associated suspension units but lie at least substantially between the upper and lower suspension arms when viewed from the side.

The differential gear unit is connected to a pair of wheel hubs 12, one on either side of the chassis, by drive shafts 20, which extend through apertures 21 in respective side members 11, and by universal joints 22 and 23 at opposite ends of each drive shaft 20.

The apertures 21 are formed in the lower regions of the side members 11 and, as shown best in Figure 2, the side members 11 are reinforced below the apertures 21 by reinforcing members 24 which project downwards between the two limbs of the lower wishbone 15 If the chassis has more than one pair of driven wheel hubs, more than one driving head will be provided.

Steering links (not shown) to steerable wheel hubs may also extend through apertures in respective side members of the chassis frame 10.

The chassis described above is typically suited to heavy commercial vehicles and off-the-road vehicles, e.g. air field crash trucks.

The embodiment described above is given by way of example only and various modifications may be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims. For example, the independent suspension system could include hydraulic anti-roll units as described in our co-pending British Patent Application no. 9116686.8. The coiled springs are not essential; instead it would be possible to employ, inter alia, torsion bars, air chambers or hydraulic struts. Also, instead of providing drive shafts from the driving head to the wheel hubs, hub motors could be provided.

Claims (10)

1. A vehicle chassis comprising a chassis unit having two spaced side members extending in a direction parallel to the intended direction of travel of the vehicle, and a plurality of independent suspension units, each supporting a wheel hub and each having upper and lower suspension arms connected between the chassis unit and a respective wheel hub, wherein the side members of the chassis unit extend between the upper and lower suspension arms of associated suspension units, or lie at least substantially between the upper and lower suspension arms of associated suspension units when viewed from the side.

2. A vehicle chassis as claimed in claim 1, wherein the chassis unit is in the form of a chassis frame having, in addition to the two spaced side members, two or more cross members extending between the two side members.

3. A vehicle chassis as claimed in claim 1 or claim 2, wherein the chassis also includes two drive shafts connecting a differential gear to a pair of wheel hubs, one on each side of the chassis, and wherein the two drive shafts extend through respective apertures in respective side members of the chassis unit.

4. A vehicle chassis as claimed in any one of the preceding claims, wherein at least one of the upper and lower suspension arms of each suspension unit is in the form of a wishbone.

5. A vehicle chassis as claimed in any one of the preceding claims, wherein each suspension unit also comprises a coiled spring and a shock absorber.

6. A vehicle chassis as claimed in any one of the preceding claims, wherein steering links to steerable wheel hubs extend through apertures in the side members of the chassis unit.

7. A vehicle chassis as claimed in any one of the preceding claims, further comprising hydraulic anti-roll units.

8. A vehicle chassis substantially as hereinbefore described with reference to the accompanying drawings.

9. A vehicle having a chassis according to any one of the preceding claims.

10. An airfield crash truck having a chassis according to any one of the preceding claims.