Mesh stiffness and nonlinear dynamic response of a spur gear pair considering tribo-dynamic effect

Lubricant between teeth fills the backlash and provides a supporting stiffness, while the traditional gear dynamics neglect the effect of lubrication. In this work, a coupled tribo-dynamic model for a spur gear pair is proposed incorporating the lubrication sub-model and the torsional dynamic sub-model. This model considers both the load-dependent combined mesh stiffness and nonlinear backlash due to lubricant. The dynamic sub-model predicts the dynamic mesh force used in the lubrication sub-model, which also provides the load-dependent stiffness for the dynamic prediction. Compared with the dry contact condition, the proposed method shows a slight variation of vibration under the permanent contact condition, but an obvious reduction in vibration amplitude when contact loss occurs. Under the effect of the lubrication, the obtained mean values of dynamic transmission error decrease over a large range of rotational speeds. Meanwhile, near the resonance regions, the peak-to-peak values of dynamic transmission error, the extents of dual-value region and the contact loss percentages all decrease.