Influences of profile modification on dynamic characteristics of involute spur gears under a fluctuating torque

The influences of rotating speed fluctuation and the phase shift between forward and backward contact on mesh point position were analyzed. Combining boundary conditions of single-tooth meshing, double-tooth meshing, and profile modification and using the analytical method to calculate mesh stiffness, a nonlinear mesh stiffness model was established to achieve a real-time feedback with the nonlinear dynamic model of spur gears and produce a more precise mathematical model of gear meshing process. A 2-DOF nonlinear dynamic model of a spur gear pair with input torque fluctuation was established by taking backlash and nonlinear mesh stiffness into account. Based on the nonlinear dynamic model, the influence of profile modification on the dynamic behavior of the spur gear pair was studied. The resluts showed that the amount of profile modification significantly affects the dynamic characteristics of the spur gear pair, and an optimal amount of profile modification exists to make the dynamic load factor reach the minimum; when the amount of profile modification exceeds a certain critical value, single-side-impact or double-side-impact occurs and the gear dynamic loads significantly increase; increasing the length of profile modification can reduce the minimum value of the dynamic load factor under a certain input torque; the maximum amount of profile modification should be the combined tooth deformation at the highest point of single tooth contact under the minimum input torque.