Experimental Analysis of the Relative Motion of a Gear Pair under Rattle Conditions Induced by Multi-harmonic Excitation

The article presents an analysis of gear rattle induced by multi-harmonic excitation. The analysis is conducted by an experimental point of view. The excitation of gear rattle in the automotive gear box derives from the law of speed of the I.C. engine and is generally of periodic type. Many analyses consider a sinusoidal law of speed, but a multiharmonic excitation, as a sum of two harmonic components how that adopted in the paper, could be more realistic for the study. An interesting behavior has been observed in the gears when varying the second order harmonic amplitude of the excitation. The dynamic behavior has been evaluated by the use of a test rig for unloaded gear pairs and results of experimental tests, in the time and frequency domain, well agree with some numerical simulations conducted by the use of a theoretical model previously developed by the authors.