Analytical model to predict electro-mechanical steering gear performance based on gears mesh quality

In the present paper, an analytical model to predict the performance of a mechanical rack and pinion steering gear is presented. One of the peculiarities of the gears used in those systems is that the rack axis cannot be fixed during the meshing to avoid jamming in the steering effort. The consequence is a need of an operational clearance that at the same time must be kept as small as possible to achieve satisfactory noise performance, avoiding gear rattle. The results will be used by gear designers to select the correct quality class of the gears, and of each individual gear parameter, that will guarantee to meet the functional performance requirements, imposed by the vehicles constructor, leading to cost reduction of gear manufacturing. Multibody simulations on reverse engineered components and experimental data collected from functional bench tests have been used to validate this study.