Review on Tooth Flank Fracture Failure of Hardened Gears

Abstract

There is a new tooth failure mode for hardened gears called tooth flank fracture(TFF). ISO published a technical specification for calculating the load capacity of tooth flank failure in 2019. This failure mode is a fatigue phenomenon with initial crack initiating in the transition zone between the case hardened layer and the tooth core. Its failure mechanism is different from the traditional pitting and tooth root breakage fatigue failure modes. The main characteristics，research status，calculation methods and main influencing factors of tooth flank fracture failure are summarized. It provides a theoretical basis for understanding tooth flank fracture failure.

Keywords

• Hardened gears
• Tooth flank fracture
• Shear stress
• Material exposure value