Nonlinear dynamic behaviour and severity of lightly loaded gear rattle under different vibro-impact models and internal excitations

This investigation comprehensively compared the elastic contact and the modified stiff impact models, aiming for the backlash-induced nonlinear vibro-impact gear rattle under lightly loaded conditions. Three meshing force models in backlash are incorporated into the elastic model independently. Unlike the previous uncoupled stiff impact model, the modified impact model employed in this paper considers the coupling between the pinion and gearwheel. Three scenarios were investigated with different components of two internal excitations, static transmission error-induced periodical backlash and the time-varying meshing stiffness. The numerical results show that the free and forced gear motion, nonlinear characteristics and rattle severity are significantly affected by static transmission error rather than time-varying meshing stiffness. Two studied hydrodynamic lubricant models show different damping effects throughout the free vibration response. The forced gear motion and rattle sensitivities show a noticeable difference below 40 rad/s2 and turn to a slight variation above 60rad/s2. The high excitation level taking over the backlash determines the dynamic characteristics more deterministically than the internal excitations. Finally, the hydrodynamic lubricant model containing only the oil squeeze effect will likely match the experimental results obtained from the dedicated rattle test bench under several conditions. The experimentally detected components of the static transmission error on the gearwheel suggest that an acceptable model should be considered in the gear rattle model.