M. Otto

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.

Assessment of the Vibration Excitation and Optimization of Cylindrical Gears

Vibration and noise generation of gear stages is mainly caused by the excitation of the gear mesh. This excitation is significantly influenced by geometry of the tooth. Here, both the macro-geometry (main geometry) and the micro-geometry (flank corrections) of the teeth are important. Corrections of the tooth flanks usually have to meet the requirements of low excitation and high load capacity. Furthermore it is oftenly necessary, especially for transmissions with variable speed, to account for the dynamic effects (e.g. resonance behavior) of noise excitation. The computer program DZP (Dynamic Tooth Force Program) provides extensive calculation methods for analyzing mesh excitation and transmission dynamics. The frame program DZPopt provides extensive possibilities to determine an optimum excitation flank correction based on the calculation capabilities of DZP.© 2011 ASME