Influence of Gearbox Flexibilities on Dynamic Overloads

Geared transmissions are prone to harmful vibrations and annoying noise emissions. The sources of excitation of those vibrations are many and different in nature, starting from torque fluctuations from the engine or the unsteady aerodynamics in wind turbines, for example. However, the main source of excitation comes from an intrinsic characteristic of meshing gears and is the time-varying mesh stiffness which is generated by the transmission error. Several flexibilities can be accounted for the calculation of the transmission error depending on the complexity of the model employed. In this chapter, the importance of including shaft flexibilities is highlighted. A nonlinear semi-analytical model is applied to the study of a simple test case with and without the misalignment caused by the inflection of the shafts under load, and several results, such as the static transmission error and the contact pressure maps, are shown and discussed.