A STUDY ON THE EFFECT OF TOOTH FATIGUE ON THE DYNAMIC PERFORMANCE OF A GEAR PAIR - (IN THE CASE OF NITRIDED ALUMINUM CHROMIUM MOLYBDENUM STEEL GEARS)

Operational fatigue tests of nitrided gears were performed using a power circulating gear testing machine, in order to elucidate the failure mode, load carrying capacity and relation between tooth profile change and dynamic performance in the fatigue process of a nitrided aluminum-chromium-molybdenum steel gear. The failure mode was a tooth breakage by bending fatigue at the tooth fillet under a higher applied load and tooth breakage due to spalling near the pitch point under a lower applied load. The surface durability of the nitrided gear was within the range of that of case-hardened gears. The changes of tooth root strain, noise and vibration during the fatigue process were slight, since the change of tooth profile deterioration was insignificant.