Time-varying mesh stiffness model of a modified gear–rack drive with tooth friction and wear

A time-varying mesh stiffness (TVMS) model of a modified gear–rack drive with tooth friction and wear is proposed in this work. The model considers the direction variation of the tooth friction and wear influence on single gear–rack tooth pair mesh stiffness and TVMS. The TVMS of the modified gear–rack drive is calculated using the generating method and the potential energy principle and verified using the finite element method based on an engineering application of the Three Gorges ship lift. Then, TVMS models of the gear–rack drive with tooth surface friction and wear are presented based on the engagement theory of gear–rack and Archard’s wear equation. Results show that the TVMS of the gear–rack drive decreases with the increase in the tooth friction and wear. The effects of the modification coefficient and the pressure angle on the TVMS of the gear–rack drive under constant center distance are further investigated. The results indicate that the bearing capacity and dynamic performance of the gear–rack drive can be enhanced by optimizing the modification coefficient and the pressure angle.