A novel analytical model for evaluating the time-varying meshing stiffness of helical gears under irregular pitting failure

Helical gear teeth are subject to spalling, pitting and other failures under prolonged operation, which can contribute to a reduction in the time-varying meshing stiffness (TVMS) of the gear. The shape of the depression formed by the absence of the gear tooth surface is irregular in practice. Firstly, an irregular-shaped pitting model is constructed by the slicing method. On the premise of improving the transition curve, the TVMS calculation equations under the irregular pitting model are derived considering the effect of axial stiffness. Then, a randomly distributed tooth surface pitting evolution model was established by the random pitting generation function, and the effects of three different failure degrees from slight to severe pitting on the TVMS are evaluated. Eventually, the faulty helical gear pairs are constructed in Solidworks and simulated by the finite element method (FEM), verifying that the irregular pitting evolution model and calculation method proposed in this paper are effective.