Gear stress reduction using stress relief features: A review

Abstract

To increase the life of the gear against fatigue failure, which occurs because of repetitive tensile stresses at the root of the tooth is a challenging task. The inability of gear is very sudden against fatigue loading without giving any indications of failure. Many researchers gave practical ways for improving the gear design like, the use of advanced material, harden the gear surface by heat treatment and carburization, improve the surface finish by shot penning method, changing the pressure angle, use asymmetric gear tooth, modify the shape of root fillet curve, etc. But focusing at interchangeability of gear systems all these ways are insufficient. To overcome this and to achieve a reduction of stresses in the stressed zone under loading, introducing stress relief feature in those areas is a powerful technique. For stress reduction in spur gear, this research work reviews use of stress-relieving features like circular shaped, elliptical-shaped, aero fin-shaped in the stressed zone. Also, it has summarized the effect of combinations of stress relief features, optimized locations of these features to minimize the stresses and increase the life of the gear.