Conceptual design and optimization of polymer gear system for low-thrust turbofan aeroengine accessory transmission

The advancement in materials and lubrication has significantly improved the load-carrying capability of polymer gears, making them ideal for replacing metal gears in power transmission. However, this conversion is not as simple as substituting steel with polymer; it requires a thorough redesign of the structural parameters specific to polymer gears. To enable the metal-to-polymer conversion of gear in power transmission, a model for optimizing polymer gear systems was developed. An investigation of the accessory transmission system of a low-thrust turbofan aeroengine was conducted. A comprehensive performance index for the accessory transmission was developed using combined weighting coefficients to achieve the optimization goals including total mass, transmission efficiency, maximum transmission error and so on. The polymer gear system developed using the proposed optimization model demonstrated a 70.4% reduction in total mass compared to the metal gear system, as well as a transmission error decrease of over 29% when compared to polymer gear systems with standard tooth profiles. The contribution analysis results demonstrated that optimizing the tooth width, pressure angle, and addendum height of polymer gears can significantly enhance the load-carrying capacity of the polymer gear system while maximizing tooth profile flexibility.