SBIR-STTR Award

The proposed program will focus on the development of a new generation of advanced technology for rotorcraft transmission systems. This program will evaluate the viability of integrating gears with composite shafts. The aim of this work is to reduce overall weight and improve vibration characteristics. Two concepts have been identified and will be further researched. The first design includes co-molding a bearing race to a carbon fiber reinforced composite shaft. The second design integrates the composite shaft and metallic gear in a way that allows shaft misalignment in the power transmission system. These attachments will simplify gear attachment and have the potential to reduce weight by integrating parts without the need for secondary fasteners. This development work will allow for widespread application in both military and civil rotorcraft systems.

The Phase 2 effort will be used to advance the material and design technologies that were explored in the Phase 1 study of hybrid gears. In this hybrid approach, the conventional metallic web is replaced with a composite element. This alternative design generates a significant weight reduction and the potential for the reduction of noise and vibration. The Phase 2 program will make the first large scale hybrid gears that can be run in a rotating gear rig with imposed torque loading. Several full scale gears will be made as well as full scale test elements. Test results from full scale testing will be applied to computer simulation models. This effort will apply topology optimization techniques to predict the best design of the gear elements. This should enable significantly more efficient designs than those fabricated and tested in the Phase 1 program. This program will also explore a power transmission system that integrates gear and shaft into a single structure. It is hoped that this integrated system will benefit weight, noise and tolerance of misalignments.