Strengthening of transmission gear under low-amplitude loads

The strengthening effects of fatigue strength and life of single tooth bending under low-amplitude loads below the fatigue limit were investigated for transmission gears with surface heat treatment. The results showed that the remarkable strengthening effects of single tooth bending could be exhibited under different strengthening loads and cycles. There exist distributed ranges both for strengthening loads and cycles; also there exist the optimal strengthening load and cycle on each range, respectively. The strengthening equation of three-dimension for single tooth bending was acquired by data analysis and processing. The validity and practicability of strengthening under low-amplitude loads were proved directly by the running-in experiments of transmission assembly. The amount of increase of fatigue life for transmission assembly is 40% if the original running-in load is replaced by the optimal strengthening load.