Simulation of Gear Hammering With a Fully Elastic Model

In large Diesel engines often geartrains are used to drive the camshafts. As the average transmitted load is small, dynamic loads, e.g. gas forces, are typically dominant. This can result in a rattling motion of teeth within the backlash, called gear hammering. We will show that for these impact-like contacts rigid body models are not sufficient, instead, elastic models are necessary to precisely simulate contact forces. The model proposed here is a modally reduced elastic multibody model including a contact algorithm. Due to the size of the modal transformation matrices, additional ways to reduce the computational effort are necessary, e.g. a dynamic reloading scheme. The model is robust and fast enough to allow simulations of many revolutions and many contacts. Furthermore, basic experiments have been carried out to validate the model. Experimental results are presented and agree very well with the simulations.