Multibody Representation on the Coupling Between Wave Generator and Flexspline in Strain Wave Gears

Strain wave gears are widely employed in aerospace and industrial applications due to their capability to obtain a high reduction ratio with low backlash through light and compact design. Since this component is mostly used in applications requiring repeatable and high precision movements, its health assessment is crucial in assuring the required performance and avoiding unexpected failures. A detailed model of the gear, able to replicate its behavior in both nominal and degraded operating conditions, would allow simulating the presence of faults and to study their effects on the behavior of the machine on which the faulty component is mounted. The present paper describes how the initial conditions of a high-fidelity gear model can be obtained by simulating the insertion of the wave generator inside the flexspline. To do this, each tooth has been modeled as a single body with its own dynamics, connected to the surrounding teeth by equivalent visco-elastic models. The final deformed configuration of the flexspline is not imposed a priori, as commonly done, but it is directly obtained by the contact with the wave generator outer race. The simulation outcomes have been then validated with experimental data from the literature.