Simulative and experimental investigation of impacts on gear wheels

Due to durability and maintenance reasons in large Diesel engines very often geartrains are used as drive train. In these geartrains a rattling motion within the backlash behavior can be observed which is called gear hammering due to its hammering noise. Even though this motion is mainly characterized by impacts, typically classical rigid body models, originally developed for properly meshing gears, are used to simulate these contacts. In this paper it is shown that impacts associated with very compliable gear bodies, as they are often used in geartrains, do not allow to use these classical approaches for precise simulations, but instead they require an elastic approach. We present a modally reduced elastic multibody model with collision detection that can describe the important elastic effects for impacts. The results obtained with this approach agree very well to corresponding finite element analyses. The model is robust and fast and allows the simulation of many contacts and many revolutions. As the modal model is derived from a finite element model, there is no need for a heuristic choice of model parameters. Furthermore, results from basic experimental investigations with simple impact bodies are presented to validate the model.