Initial Temperature Evaluation for Flash Temperature Index of Gear Tooth

Abstract

In the AGMA standard for the scoring resistance evaluation of gears, flash temperature is used as an index indicating the risk of scoring. The flash temperature is expressed as the sum of flash rise of temperature and initial temperature. In this research, the initial temperatures are measured for various gear sets in running by thermocouples which are mounted just beneath the working surface of pinion. The effects of gear dimensions, rotating speed, and lubrication conditions on the initial temperature are clarified. An experimental formula is proposed for estimating the initial temperature, which depends on the temperature of oil inlet, the frictional power loss, and the running conditions such as rotating speed, contact position, and the oil supply rate. The estimated initial temperatures are in good agreement with the measured values. The proposed method is available for the scoring resistance evaluation of the vehicle transmissions.