Design of a TFF critical testing gear set under reverse bending

Abstract This report deals with the macro geometric design of a gear set for investigating the influence of reverse loading on the tooth flank fracture load capacity. Due to power density increase of gearboxes in the past, gears are becoming more and more subject to interior fatigue, since the tribological system as well as the material in the surface zone have been optimized continuously over the years. The influence of reverse loading on the tooth flank fracture load capacity is currently only known to a limited extent in research work. An FE-based approach for calculating the tooth flank fracture load capacity was therefore extended to include the influence of the reverse loading. In an initial analysis, the load capacity reducing influence of the reverse bending load on the tooth flank fracture load capacity has been simulated. Building on this, the present work addresses a more detailed analysis about the influence of the selected stress hypothesis and the influence of the macro geometry. The aim is, to find a gear design that reacts as sensitive as possible to an applied reverse bending load regarding the risk of tooth flank fracture. Finally, the robustness regarding a modification in hardness and residual stress curve is investigated.