Gearbox Whining Noise Modeling - Experimental Validation of a Computational Scheme

VDI, Int. Gear Conference, Munich (Germany), September 2013

The aim of this work is to present an efficient computational scheme which allows the calculation of the whining noise of complex geared systems. In this paper, the method is applied to a two-stage automotive gearbox. First the excitations, i.e. the transmission error and mesh stiffness fluctuations, are characterized from the macro and micro-geometrical characteristics of the meshing gears. The vibrations generated at the meshing are transmitted to the gearbox housing through shafts and bearings. The vibratory state of the housing is directly related to the whining noise. Thus a finite element model of the gearbox has been built in order to perform a modal analysis. The excitations are used and the dynamic equations of motion are solved in the frequency domain using an iterative scheme, which reduces considerably the computation time. Measurements have been performed on the physical system, showing that the computational scheme leads to satisfying results. Indeed, considering that the finite element model could be better tuned and that the excitation is subjected to a large variability, the differences observed between the simulations and the measurements are totally acceptable. A noise contribution ranking can be done, order by order or excitation by excitation. The order of magnitude of the dynamic response is correct. The computation time is low enough to run a large number of dynamic calculations and to perform parametric studies.