Prediction of automotive gearboxes dynamic behavior during design is made possible through the use of numerical models and virtual prototypes. But market pressures require a formalization of new mechanical design activities. The aim of the second part of these two companion papers is to exploit the results to highlight future trends in mechanical design.
Simulations performed with numerical models enable us to obtain a better understanding of the vibratory phenomena which appear in gearboxes. These models dissociate local effects, such as gear mesh phenomena, from “global” effects, due to the gearbox architecture and allow us to evaluate interactions between components. They are used for explaining some experimental observations, such as the large differences between the dynamic transmission error in “pullup position” — corresponding to an established speed or to an acceleration phase — and “pulldown position” — corresponding to a decreasing speed phase. Local gear mesh effects can not explain these large differences. They are also used for evaluating the influences of mechanical modifications to the bearing environment, on the dynamic transmission error. Then, the consequences of these results are applied to the design and optimization of new gearboxes.