Optimized acoustic design of inequidistant gearings
* Presenting author
In state-of-the-art gearings the teeth of a gearwheel are of exactly the same size and are positioned exactly with the same pitch. This leads to a periodic excitation of vibrations during the meshing process and, therefore, to tonal noise. Tonal noise is considered to be more annoying and more prominent than broadband noise. The research group SAM at TU Darmstadt developed an inequidistant gearing aiming at minimizing the overall sound pressure level, the tonality, and the annoyance of gear noise. This new kind of gearing is characterized by irregular tooth widths and irregular tooth pitches, leading to an irregular mesh and, therefore, to a less tonal noise. However, the potential to render every tooth of a gearwheel individually in its thickness and its pitch leads to a challenge in finding the optimal acoustic design. In this work, a method is presented to evaluate the noise of inequidistant gears using the results of a psychoacoustic listening test performed in previous works (DAGA 2018). This evaluation is used to perform an optimization process that comprises a combination of Monte Carlo and neighborhood search algorithms. The optimization method is applied to an exemplary automotive electric drive train.