A multi-criteria polymer gears design optimisation procedure

An open challenge is the reliable dimensioning of polymer gears due to the lack of accurate data on the fatigue strength of polymer materials, and the complex relations between geometric and operating parameters. The national standards (BS 6168:1987, JIS B 1759:2013) and the guidelines of the German engineering association VDI 2736 are available for the calculation of polymer gears. In most cases, polymer gear designers do not have a complete picture of all interactions between the design parameters, and so a larger number of iterations is required for the optimal gear design or the design of gears is oversized. We have developed the computer program, OptiTooth 10.0, for spur and helical gears that in the first step enables the variation of geometry according to different criteria: the number of teeth (z1, z2), helix angle (β), and a tooth normal module (mn). A user can have an overview over a larger number of possible solutions, as well as how the design parameters influence the target criteria. The objective is to fulfil the torque transfer function in the smallest volume. In the second step, the user conducts a detailed control calculation for the selected gears, and the computer program prepares the results of gear calculation and all geometric values of the gears.