The PVT limit for gear scuffing assessment

Abstract

The growing interest in gear scuffing research primarily stems from the escalating standards and operation requirements in aero-engines and electric vehicles, particularly under high-temperature, high-speed, and heavy-load conditions. Existing calculation standards for gear scuffing often deviate when evaluating the load-carrying capacity under different rotational speeds or oil temperatures, thus undermining the reliability of gear scuffing assessments. To address this, thirty-five sets of gear scuffing experiments were conducted with different materials, manufacturing processes, and lubrication condition. A new evaluation method based on the pressure-velocity-temperature (PVT) limit was proposed for assessing gear scuffing resistance. Using a non-dominated genetic algorithm, exponent coefficients for the contact pressure P, sliding velocity V, and lubricant temperature T were determined. The results demonstrated that the proposed PVT limit effectively evaluates gear scuffing resistance across various conditions. The PVT limits across different operating scenarios, under the same material, manufacturing process, and lubrication conditions, showed a maximum deviation of 6.6%. Conversely, the scuffing temperatures calculated using ISO 6336-20-2017 and AGMA 925-A03-2003 standards deviate from experimental results by up to 36.7% and 32.8%, respectively. Further application of the PVT limit to an aero-engine accessory gearbox confirmed the practical applicability of the proposed method.