Numerical study of noise and vibration behaviour of lightweight gearbox housing

The gearbox housing is one of the main components of an electric vehicle which has an influence on the NVH behaviour of the gearbox and overall vehicle, especially in the context of e-mobility. Vibrations inside the gearbox are mainly excited at the gear mesh and then transmitted to the housing through shafts and bearings, where it is radiated as air-borne noise. Because of the importance of reducing the weight of electric vehicles, housing structures are often target of lightweight design measures, which, in turn, often lead to worsened NVH behaviour.
In this paper, the effects of different lightweight design measures on the vibrational behaviour of a gearbox housing are evaluated by numerical simulations. Firstly, the basic model (without lightweight design) has been simulated numerically in a commercial finite element software to extract the natural frequencies, mode shapes and frequency response functions for specific points of interest. These results have been verified by the measurement using 3D laser scanning vibrometer. Then, multiple variants of the electric vehicle gearbox housing are created in CAD and numerically simulated with different lightweight design. The results of the modal analysis provide valuable insights on the vibrational behaviour due to lightweight design measures.