Land vehicles – Wheeled – Running gear
Reexamination Certificate
1999-12-20
2002-12-31
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Running gear
C280S124100, C280S124178, C280S124165, C280S124137, C280S124103, C280S005506
Reexamination Certificate
active
06499754
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to vehicle suspension system for use in automobiles, trucks and other vehicles.
2. Description of the Related Art
In the applicant's earlier Australian patent application No. 19420/95, there is shown a vehicle suspension system including two laterally spaced front wheel assemblies and two laterally spaced rear wheel assemblies. In each of the arrangements described in the above noted patent application, a first coupling means for interconnecting laterally spaced wheel assemblies is respectively provided at the front and the rear ends of the vehicle. Second coupling means for respectively interconnecting the longitudinally adjacent wheel assemblies are provided on each side of the vehicle. The first coupling means primarily support the weight of the vehicle body and provide four wheel bounce resilience whereas the second coupling means provides roll attitude control for the vehicle. In the arrangements described in this patent application, the first coupling means are generally provided by a pair of contra-rotational torsion bars respectively located at the front and rear of the vehicle. The second coupling means are also provided by a pair of contra-rotational torsion bars respectively provided on each side of the vehicle. A lateral roll control arrangement links the second coupling means. This suspension system provides for movement of one wheel in one direction resulting in the longitudinally adjacent and laterally adjacent wheels being respectively urged in the opposite direction. Furthermore movement of both wheels on one side of the vehicle in one direction during roll movement of the vehicle will urge movement of both the wheels on the other side of the vehicle in the same direction to thereby control vehicle roll; Details of the vehicle suspension system described in the above noted patent application are incorporated herein by reference.
It has been found in practice that it is difficult to accommodate a vehicle suspension system of the above noted type into existing vehicles because of the limited space provided under these vehicles and the configuration of the components of the vehicle as they have not been specifically designed to allow for such a vehicle suspension system. More particularly, these above noted types of suspension system may input suspension loads into the body structure at different points to conventional suspension systems. Due to the mechanical advantage (or motion ratio) of some elements of the suspension linkages to the wheel, these suspension loads may cause deflection and therefore noise if input directly into the lightweight structures of modern monocoque (or unitary) construction vehicle body shells.
Additionally, in the suspension system described in the aforementioned Australian application, only one form of low roll stiffness bounce support means is disclosed. It may be advantageous to use alternative arrangements of low roll stiffness bounce support, to facilitate packaging of the suspension system on a wider range of vehicles. Alternatively, it may be advantageous for the roll control arrangement be used in conjunction with conventional independent support arrangements for each wheel, which may provide a roll stiffness and therefore a warp (or cross-axle articulation) stiffness.
SUMMARY OF THE INVENTION
The object of the present invention is therefore to provide a vehicle suspension system of the above noted type that can be accommodated under existing vehicles, preferably without inputting large loads into the body structure of the vehicle.
With this in mind, according to one aspect of the present invention provides a suspension system for a vehicle, the suspension system including:
two laterally spaced front wheel assemblies and two laterally spaced rear wheel assemblies, each wheel assembly including a wheel and a wheel mounting supporting the wheel to permit movement of the wheel in a generally vertical direction relative to a body of the vehicle;
bounce support means for supporting the vehicle body above the wheels and roll control means for controlling a roll attitude of the vehicle body with respect to the wheels;
said roll control means including respective second coupling means interconnecting each wheel assembly to the longitudinally adjacent wheel assembly, and further including transfer means interconnecting the second coupling means of each said pair of longitudinally adjacent wheel assemblies;
said second coupling means being adapted to urge in response to a movement of the wheel of one said wheel assembly in a substantially vertical direction a movement of the wheel of another said wheel assembly connected to said same second coupling means in an opposing direction relative thereto;
said second coupling means also including average movement generating means arranged to generate a movement therein substantially proportional to the average movement of the two wheels connected thereto on one side of the vehicle, said generated average including a factor for the roll moment distribution of the roll control means, the transfer means transferring said generated average movement of said second coupling means to the other said second coupling means on the opposite side of the vehicle;
wherein the loads generated in the average movement generation means and the transfer means are resolved in a localised structural area of the suspension system, and
wherein the bounce support means and roll control means respectively provide separate bounce and roll stiffness for the vehicle.
The suspension system can take advantage of spaces located under the vehicle to locate components which resolve the transverse suspension loads (generated in the roll control means) by suitable location of the structural area(s).
The second coupling means may be used on a vehicle provided with conventional independent supports (which provide additional roll stiffness).
However it may be preferable to provide bounce support means including respective first coupling means interconnecting each said wheel assembly to the laterally adjacent wheel assembly to provide a complete suspension system with substantially zero warp (or cross-axle articulation) stiffness.
Alternatively a compromise between conventional independent supports and the preferred interconnected supports may be chosen. The bounce support means for at least one pair of laterally spaced wheel assemblies may include at least a first coupling means interconnecting each said wheel assembly, said first coupling means supporting at least a portion of the load on the associated wheel assemblies whilst providing substantially no roll stiffness.
Where at least one first coupling means is provided, a height adjustment means may also be included to vary the average height of the body with respect to the associated wheels.
The substantially transverse suspension loads generated by the suspension arrangement may be resolved in at least one subframe upon which the vehicle body is supported. The front and rear wheel mountings may be respectively located on separate subframes, the roll control loads being resolved on at least one of the subframes. Alternatively, the roll control loads may be resolved on a further subframe. It is also envisaged that the transverse suspension loads be resolved in at least one reinforced structural area of the vehicle body.
The use of suspension subframes is advantageous for assembly of the vehicle on a production line. Parts or all of the suspension system may be produced as one or more sub-assemblies which are easily attached onto the vehicle body during whole vehicle assembly on a production line. One subframe could be provided with the suspension system attached to allow easy assembly and resolve all the loads.
Each second coupling means may include a roll lever arm for each said wheel assembly, the load in each roll lever arm varying in response to the warp and roll displacements of the wheels with respect to the body, and each second coupling means may include a linkage arrangement inte
Heyring Christopher Brian
Robertson Alexander John
Birch & Stewart Kolasch & Birch, LLP
Johnson Brian L.
Kinetic Limited
Shriver J. Allen
LandOfFree
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