Effects of helix deviation on load distributions and bending stresses of continuous engaged helical gear drives

Abstract

The research of the load distributions and bending stresses with helix deviations in power transmission systems is important for effectively improving gear load capacity. The equations of tooth surface with helix slope and form deviation were established by the given forming rack-cutter tool and the path for processing rack-cutter tool. And various kinds of engaged helical gear models with helix slope and form deviation were developed using finite element method software. Finally, tooth surface load distribution and tooth root bending stress were numerically calculated. The effects of the helix slope deviation, different shape, period, and amplitude of helix form deviation on tooth surface load distribution and tooth root bending stress were investigated and the results were compared to each other as specified by grades 5 and 7. It is found that the single helix slope deviation on tooth surface load distribution and tooth root bending stress shows “superposition” effect. Especially, the different shapes, periods, and amplitudes of helix form deviation exhibit significant effect on tooth surface load distribution and tooth root bending stress. Helix form deviation mainly affects the tooth surface load distribution and tooth root bending stress along the tooth longitudinal direction, while has little impact between tooth pairs. The study benefits gear load capacity analysis and provides valuable guidelines for improving the performance of power transmission systems.