ABSTRACT−The research is carried out to improve passenger's comfort to increase the vehicles stability in dynamic conditions. The literature available in the automotive engineering considers different topics for studying suspensions. An example represents mechanisms structure and analysis (synthesis, kinematics, and dynamics) under various operating conditions. These aspects have been approached before analytically, numerical. The current paper studies the influence of the lateral force on the contact patch of the wheel and the corresponding variations of vehicle stability parameters, such as camber angle and wheel rear track. The study is performed for a newer innovative rear suspensions mechanism which does not have a wheel track and camber angle variation, relative to the chassis, when the suspension components was considered rigid. A numerical solution is obtained through a virtual model on several commercial codes: MSC Adams, Patran, Nastran. Concerning the analysed parametes, their variation increases as the applied force is increased. Moreover, the largest variation corresponds to the case were elastic bushings and deformable links are considered.

Multi-link rear axles offer some important advantages relative to vehicle handling. But the structure of the multilink split type generally determines kinematic incompatibilities in its operation. The paper studies some aspects surrounding constructive solutions that could minimize these kinematic incompatibilities. Some rear axle mechanisms from different cars were measured and analyzed as component shape by authors; this process allows the geometrical modeling and animation of systems using specialized software (Autodesk Inventor Professional 8). The effects of these modeled structures (the variations of track width and wheel camber angle) have been studied using the above-mentioned software. The variation of track width caused by the studied mechanisms along the compression and relaxation of the suspension spring defines the trajectory of the tyre contact patch. The results are contextualized in diagrams showing that the modifications of the analyzed parameters are very important, with a negative influence on car stability and the comfort of passengers. The interpretation of these diagrams allows the choice of favorable constructive solutions to increase car performance.