The effects of the shape of tooth profile modifications on the transmission error, bending, and contact stress of spur gears

Nowadays, the basic requirements of gear transmissions are not limited to resistance and reliability, but often include good efficiency and low vibration and noise emissions. This article investigates the role of tooth flank micro-geometry in fulfilling these needs. A non-linear finite element approach has been conceived and exploited to investigate in detail the influence of the shape of profile modifications (PMs) on transmission error, root stress, and contact pressure. In this approach, the contact between teeth flanks is handled by ABAQUS general purpose contact algorithm without introducing any simplification based on gear geometry peculiarities. The boundary conditions are defined so that it is possible to automatically run a sequence of static analyses. The numerical results are first assessed by comparison with experimental measurements and then a comparison of contact and bending stresses of the same gear with long linear and long circular PMs is presented and discussed. The results of these comparisons show that the optimal amount of PMs is not independent of PM shape; hence, the procedures used to design linear PMs cannot be directly applied to the design of non-linear PMs.