Resolution of micropitting in case-carburized helical gear pairs through tooth profile modification

Helical gears are crucial for power transmission in parallel shaft systems, operating under various conditions such as load, speed, temperature, and environmental factors. These gears are typically case-hardened through carburization to handle higher torque transmission. However, this capability also introduces surface fatigue stresses, leading to potential surface-related failures. Micropitting is one such failure, characterized by changes in the tooth flank's surface texture, which can escalate and result in catastrophic damage.This research compares the outcomes of analytical and experimental investigations to identify potential zones where micropitting may initiate. The analytical approach was conducted using the KISSsys model, while the experimental work involved applying loads to the gearbox shaft using a dynamometer test rig under a defined load cycle.To assess changes in the gear surface, gear profile analysis was performed using a Zeiss CMM machine equipped with the GearPro program. It was evident that micropitting began below the pinion's pitch line. The tooth profile was subsequently modified with lead and crown adjustments. Following these modifications, micropitting was no longer observed during the same testing cycle. This finding was further validated through gear profile analysis.