Lubrication and thermal characteristics for thin-web cylindrical helical gears with high linear velocity

High-speed gears mostly use forced lubrication. However, oil jets at the meshing exit face air barriers from gear rotation, hindering lubricant delivery, weakening lubrication and cooling effects, and often causing gear overheating. This paper proposes a thermal-fluid hybrid model for helical gears optimized for oil jet lubrication parameters, integrating an SPH-based gearbox CFD model to determine convective heat transfer coefficients, a helical gear meshing model to calculate frictional heat flux, and a finite element model with coordinate-mapped thermal boundaries to simulate temperature rise. Experiments validate its accurate prediction of high-speed helical gear temperature rise and confirm that optimizing exit-side oil jet parameters effectively suppresses overheating.