Derivation of high efficiency two-stage epicyclic gears

Power and torque dividing between the members of coaxial two-stage epicyclic gears is examined. A method is developed for identifying only arrangements that avoid internal recirculation of power, a necessary condition for least losses and highest bearing life. Sixteen possible interconnections of coaxial gears that divide input power are derived, their speed-ratio zones tabulated, and applications to vehicle transmissions and turboprop reduction gears noted.