Development of Face Gear Technology for Industrial and Aerospace Power Transmission

Tests of a 250 horsepower proof-of-concept POC split torque face gear transmission were completed by The Boeing Company in Mesa, Arizona, while working under a Defense Advanced Research Projects Agency DARPA Technology Reinvestment Program TRP. This report provides a summary of these cooperative tests, which were jointly funded by Boeing and DARPA. Design, manufacture and testing of the scaled-power TRP split torque gearbox followed preliminary evaluations of the concept performed early in the program. The testing demonstrated the theory of operation for the concentric, tapered face gear assembly. The results showed that the use of floating pinions in a concentric face gear arrangement produces a nearly even torque split. The POC split torque tests determined that, with some improvements, face gears can be applied effectively in a split torque configuration which yields significant weight, cost and reliability improvements over conventional designs.