Study on Bending Fatigue Strength of Helical Gears : 5th Report, Effect of Load Variation on Bending Fatigue Strength

This paper presents a study on the effect of load variation on the bending fatigue strength of helical gears. A bending fatigue testing machine for cylindrical gears controlled by a micro computer was developed, and the bending fatigue tests of helical gears were carried out under a uniform cyclic load and a varying load which had the load spectrum of normal distribution. Various cumulative fatigue damage rules (Miner's rule, modified Miner's rule and VDI-Richtlinien 2151) were compared on the basis of the experimental results, and the effect of load variation on the bending fatigue strength of helical gears was clarified to a considerable extent. Furthermore the effect of understress on the bending fatigue life was investigated.