Gear noise prediction in automotive transmissions

Due to the increasing requirements regarding the vibrational behaviour of automotive transmissions, it is necessary to develop the reliable methods for noise evaluation and design optimization. Continuous research led to the development of an elaborate method for gear noise evaluation. This method is used in a comparison between measurement and calculation of gear noise excitation in a gearbox from series production. A detailed analysis of the results allows to diversify between the excitation effects of design micro geometry and manufacturing deviations. Calculational examinations of mesh excitation for two automotive gearboxes were performed. In the first step the gear meshes with their designed main and micro geometry was modelled, then the dynamic behavior of shafts, bearings and housing were taken into account. After transmission error and dynamic tooth force were calculated, the mesh excitation of designed and topologically measured microgeometry were compared. As a result, the microgeometry structure had a significant impact on the excitation behaviour. The calculation results were confirmed by the noise measurement of two automotive gearboxes. The presented methodology enables the gear engineer to optimize the microgeometry with respect to the robust manufacturing.