scope:

The risk of gear tooth scuffing in commercial vehicle transmissions has gained more attention because of increasing demand for fuel-efficient powertrain systems in which diesel engines run at lower speeds, power density is higher, and lubricants are modified to improve efficiency and compatibility with components of new technologies, such as dual clutch transmissions. Thus, predicting scuffing risk during the design phase is vital for the development of commercial vehicle transmissions. AGMA 925-A03 is a comprehensive method to predict the probability of gear scuffing. Therefore, this paper presents the AGMA 925-A03 scuffing risk predictions for a series of spur and helical gear sets in transmissions that are used in commercial vehicles ranging from SAE class 3 through class 8. Limiting scuffing temperatures of mineral and synthetic lubricants were determined from FZG scuffing tests, dynamometer tests and field data. The agreement between prediction, test results and actual usage can provide confidence in the predictor of scuffing risk of gears in commercial vehicle transmissions.