Multibody modelling of shuttling excitation in spur and helical geared transmissions

In this paper the effects of gear contact force shuttling (axial movement of the resultant contact force point of application) are discussed as an important excitation which is seldom included in gear modelling. The main phenomena which generate this excitation are discussed. Two formulations are proposed for multibody models, where computational efficiency must be kept high in order to perform speed-sweep dynamic simulations at a global system level. One formulation is based on static contact calculations, the other is simplified and only accounts for angular misalignment in the plane of action. The effects of shuttling become more important when supporting bearings are very close to each other and under the gear bodies, since the load acting on each bearing becomes more sensitive to contact load distribution on the gear teeth and to gear-tilting modes. Planet bearings in planetary gear stages are a widespread example in this direction. The proposed models are applied and results are discussed for this case study.