Influence of tooth profile modification on helical gear durability

A nonlinear finite element contact mechanics model of a helical gear pair was used to study the effect of intentional tooth profile modifications on durability of helical gear pairs. Both two-dimensional (2D) and three-dimensional (3D) modifications were considered. A detailed parametric study was performed to quantify the changes in the contact and bending stresses as a function of tooth profile modification parameters as compared to an unmodified gear pair baseline. The combined influence of modification parameters and torque transmitted on the maximum stresses is described. Results indicate that both bending and contact stresses of a helical gear pair are increased significantly when 2D modifications are applied, potentially causing an underestimation of the actual stress values when the modifications are not included in stress calculations. When properly selected, 3D modifications cause significantly less stress increases.