Effects of helix angle, mechanical errors, and coefficient of friction on the time-varying tooth-root stress of helical gears

Accurate estimation of tooth-root stress has been of great interest to researchers and engineers to prevent catastrophic damage of gear transmission system. However, analytical models in AGMA standard are not precise and FEM are mostly focused on the analysis of spur gear pairs. As a result, very little research has been conducted to investigate the time-varying tooth-root stress of helical gears. In this study, effects of helix angle, mechanical errors, and coefficient of friction on the time-varying tooth-root stress of helical gears has been rigorously investigated based on our previous proposed method. 10% tensile stress and compressive stress could be reduced with the increase of helical angle. Coefficient of friction has significant effects on the tensile stress of gear pairs. The peak value of time-varying tooth-root stress shifts from HPSTC to LPSTC due to its influence. The increase of parallel misalignment could reduce up to 18% tensile stress during approach process in double tooth contact condition.