Analysis investigation of the influence of sub-surface shear stress distribution of spur gear

Spur gears endure contact fatigue loads that can lead to surface damage on the gear teeth. Contact fatigue typically arises from dedendum during engineering and experiments, primarily caused by maximum sub-surface shear stress. This study presents a contact model incorporating profile-shift to examine sub-surface shear stress in relation to the occurrence of tooth root pits. Accurate calculations are performed to determine the distribution of sub-surface stress and meshing duration, considering various modification coefficients. The geometric cause affecting the shear stress near the tooth root is found. A deviation coefficient from base circle is proposed to analyze the influence of modification coefficient and pressure angle, which can be used in design reference. The investigation comprehensively explores the effects of profile-shift and pressure angle of spur gears on stress distribution.