Simulation of passenger car synchronizer ring movement during rattling

Abstract

This article presents a model for the calculation of the hydrodynamic forces and vibration behaviour of a passenger car synchronizer ring during rattling, i.e. a ring which is excited by rotational speed irregularities and therefore moves within its functional clearance. The hydrodynamic forces are calculated on basis of the Reynolds equation for thin fluid films. An analytical solution and a numerical one of the Reynolds equation are presented for both dry and mixed frictions. The oil-slung-out effect in the synchronizer ring gap is also taken into account in the solution. For the simulation, a multi-body system of the gearbox inner parts and a finite element model of the gearbox housing have been developed. The simulation results show the synchronizer ring movement, oil film thickness, and oil pressure distribution at different torsional excitation levels. The influence of different oil viscosities, the maximum oil film thickness, and wear of the synchronizer ring friction lining is investigated in parameter studies. Finally, the simulation results are validated by experimental measurements on an automotive transmission rattle test bench with a single-stage gearbox. The measurement results show that the developed model is capable of representing the principal characteristics of a synchronizer ring during rattling.