Optimisation of polymer spur gear pairs with experimental validation

This study aims to present a procedure for optimisation of polymer gear pairs, along with the rough design guidelines. Multi-objective optimisation of polymer spur gear pairs was carried out. The gear pair module, face width, pinion number of teeth, and profile shift coefficients of both gears served as design variables. Two objective functions were used to rate the designs—volume and frictional power losses. Compared with well-researched steel gear pair optimisation, additional boundary conditions were necessary: tooth flank and root temperatures, abrasion wear, and tooth addendum displacement. Two arbitrary datasets were used as examples, each made of polyoxymethylene. For each of the sets, a Pareto optimal solution was manufactured to enable the experimental validation. For this purpose, an open-circuit experimental rig was designed. As no literature was found on the polymer gear pair optimisation, results were compared with ones for steel gear pairs. The results have shown that changes in macro-geometry affect polymer gears significantly different. The lower volume pairs made of polymer had greater face widths, while the opposite was observed in steel gears. The differences between the analytical and experimental results were up to 21%.