Investigation into the tribo-dynamics of spur gear pairs considering pitch deviations and lubrication

Pitch deviation, one of the long-wave deviations, has been demonstrated to be a significant contributor to noise generation in the drive train of motor vehicles operating at higher speeds. Until now, numerous studies have been conducted to investigate the effects of pitch deviation on the dynamic characteristics of gear systems. However, these models often exhibit inconsistencies with real-world observations due to the simplification of the contact between teeth pairs. This simplification ignores clearance compensation and damping of the oil film. To fill this gap, a new numerical model of spur gear systems with pitch deviation considering lubrication is proposed. An analytical model of time-varying mesh stiffness (TVMS) and meshing impact force for spur gear pairs is proposed, in which the geometric relationship and iterative solution process have been investigated. An improved tribo-dynamic model is established to investigate the excitation behavior of gear pairs with pitch deviation under lubrication. The accuracy of the proposed model is verified through comparisons with references and experimental results. Results show that the random impact phenomenon of TVMS is significantly suppressed by oil film, and the meshing impact force is also reduced. The transmission stability of spur gear pairs with tooth pitch deviation is improved under lubrication. The research results provide theoretical support for accurately predicting the dynamic responses of spur gear pairs with different precision levels considering lubrication.