Planetary Gear Analysis and Synthesis for K-MAX Helicopter Rotor Transmission

摘要

In this paper the general behavior of fixed ring gear - simple planetary gear trains in terms of speed, weight, and torque are analyzed for 3, 4, 5, 6 and 7 planetary gear arrangement conditions. Both tooth bending and contact stress conditions are investigated based on the existing transmission system of the K-MAX Helicopter. Alternatively, general behavior of transmission with a conceptual variable speed - power split epicyclic gear train (PSET) with a rotating ring gear for K-MAX drive train is determined for kinematical analysis. Kinematical design variables and constraints are identified for such systems which can be used for a research of a potential variable speed transmission for the K-MAX. The results conclude that lower output speed transmissions needs to have larger gears because of the high torque occurring on the gear. Different numbers of planet cases have different advantages; for instant 3 planets case can provide low weight with high stress values on the tooth form while same reduction ratio 5 planet case gives higher weight and lower stress. This research also provides general behavior of 2 output speed PSET type epicyclic gears for the future rotorcraft transmission applications. These variable speed preliminary designs lead to 2 speed transmissions up to 25% speed change. Because of power the splitting the gear train has lower torque during the low output speed state.