REDUCTION OF ROOT FILLET STRESS BY ALTERNATIVE ROOT FILLET PROFILE

M. S. Hebbal, T. M. Ishwar, P. Rayannavar, K. H. Prakash

Abstract: While generating the working profile (involute) of a spur gear using rack cutter, the root fillet curve is generated, automatically which is a trochoid. The root fillet obtained thus is not necessarily an optimum profile in context to the bending stress induced during its operation. This work investigates the stress at the gear tooth profile by replacing the conventional trochoid fillet by polynomial curves. The circular root fillet profile is constructed by drawing an arc tangent to working profiles and root circle and this arc is taken as reference root fillet to generate alternative root fillet profile . The arc is divided into six segments. New fillet profiles are constructed by displacing the middle points radially using different relations and keeping the end points fixed. The improved root fillet profiles resulted into reduction of bending stress by 9 to12 percentage. This results presented here are based on two dimensional finite element analysis (FEA).

Keywords: Spur gear, Bending stress, Root fillet profile, FEA

DOI: https://doi.org/10.15623/ijret.2014.0315155