A dynamic calculation method of sliding friction losses for a helical gear pair

Sliding friction losses play a significant role in power losses of a gearbox. The author has proposed a calculation method of sliding friction losses considering the transmission errors. The tooth surface meshing force, relative sliding/entrainment velocity, and sliding friction coefficient are obtained under static or quasi-static conditions which restrict the accuracy of model in the middle- and high-speed gear transmission. The efficiency of dynamic state of a helical gear pair is studied, because it is widely used in the middle- and high-speed transmission. Therefore, a calculation method for helical gear pair of sliding friction losses based on dynamic characteristics is proposed. First, the dynamic model of helical gear pair considering friction and multiple backlashes is built and solved. The parameters associated with the calculation of sliding friction loss are obtained. Second, the tooth surface meshing force and relative sliding/entrainment velocity are calculated and brought into the formula of sliding friction coefficient. The formula of sliding friction losses is given, and the meshing efficiency considering the sliding friction losses in helical gear pair is calculated. Finally, by a comparison with Ref. [1] (Wang et al., J Mech Eng Sci, 230(9):1521–1531, 2016), we mainly propose an idea for calculating the sliding friction losses using dynamics instead of static method or quasi-static method.