Analytical procedure for the optimization of plastic gear tooth root

The increasing diffusion of plastic gears in many industrial sectors makes it necessary to have a better knowledge of the bending strength properties of teeth in order to ensure an adequate design process. However, technological development has not gone hand in hand with the standard development necessary to carry out an optimized design process. To date, the specific standards for plastic gears refer mainly to design and calculation methods for the metal gears. So, the possible optimization strategy for the tooth root geometrical profile is also driven by the typical metal production processes. This paper presents an innovative approach, supported by an analytical procedure, to design optimized plastic gear wheels. The results obtained by the analytical approach is compared to the standardized one to highlight similarities and discrepancies. The goodness of the proposed results is verified also through finite element numerical analysis. The goal of the paper is to provide the designer with an analytical approach useful to optimize the root geometry design of plastic gears for lower root bending stress.