Research on Time-Varying Meshing Stiffness of Helical Gear Considering Tribo-dynamic Behavior

An analytical expression of oil film stiffness is proposed for helical gear based on two-dimensional EHL analysis considering the dynamic force, rotational speed, tooth blank temperature and oil viscosity. Then the tribo-dynamic equation is built to obtain the time-varying meshing stiffness of helical gear. The results show that the analytical model keeps correspondence with the numerical results well as the load and velocity change in a wide range. The load distribution is determined by the oil film stiffness to a great extent. As the velocity arising, the oil film stiffness and the dynamic load change similarly. The equivalent meshing stiffness of gear changes periodically. At low speed, the meshing stiffness is high, so vibration displacement appears tiny. However, as the rotational speed reaches in the resonance region, the meshing stiffness greatly reduces with growing vibration displacement.