Abstract:
Impulsive responses in geared systems with multiple clearances are studied when the mean torque excitation and system
load change abruptly, with application to a vehicle driveline with an automatic transmission. First, torsional lumped-mass
models of the planetary and differential gear sets are formulated using matrix elements. The model is then reduced to
address tractable nonlinear problems while successfully retaining the main modes of interest. Second, numerical
simulations for the nonlinear model are performed for transient conditions and a typical driving situation that induces an
impulsive behaviour simulated. However, initial conditions and excitation and load profiles have to be carefully defined
before the model can be numerically solved. It is shown that the impacts within the planetary or differential gears may
occur under combinations of engine, braking and vehicle load transients. Our analysis shows that the shaping of the engine
transient by the torque converter before reaching the clearance locations is more critical. Third, a free vibration experiment
is developed for an analogous driveline with multiple clearances and three experiments that excite different response
regimes have been carried out. Good correlations validate the proposed methodology.
