Analysis and research on tooth interior fatigue fracture failure of straight bevel gears
YANG Fan
WANG Rui
CHENG Xudong
WANG Xiwen
SHU Chan
LEI Xiao
Abstract：[Objective]Aiming at the tooth interior fatigue fracture failure of straight bevel gears in new energy vehicle differentials during durability tests and the lack of unified design verification standards for such failure,research on failure mechanism analysis and risk assessment was carried out.[Methods]Firstly,macroscopic morphology observation and scanning electron microscope inspection were performed on the fractured gears to identify the failure mode as subsurface low-cycle fatigue fracture.Secondly,a mechanical calculation model for tooth flank fracture was established based on ISO/TS 6336-4:2019 standard and the improved Dang Van criterion,and the material exposure values at different depths of the gear tooth were quantitatively calculated.Then,the influence laws of contact stress and residual stress on failure were analyzed.Finally,optimization measures for heat treatment process were proposed and verified by tests.[Results]The results show that tooth surface contact stress and internal residual stress are the core factors affecting the material exposure value,and crack sources initiate at the subsurface where the maximum shear stress occurs.After optimizing the shot peening process,the material exposure value in the carburized layer transition zone decreases from 1.09 to 0.87.The improved gears pass all durability tests,effectively improving the fatigue life,which provides a reference for the anti-fatigue design of straight bevel gears.
Keywords：Straight bevel gearTooth interior fatigue fractureContact stressResidual stressMaterial exposure value
Publication Date：2026-06-30
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：7( 193-199 )