A STACKED COMPOUND PLANETARY GEAR TRAIN FOR AN UPGRADED POWERTRAIN SYSTEM FOR A HELICOPTER

摘要

A stacked compound planetary gear train for an upgraded powertrain system for a helicopter that provides an increased reduction ratio to accommodate the increased horsepower output of the augmented powerplant system while concomitantly providing a baseline RPM output to the main rotor shaft. The stacked compound planetary gear train includes a driving sun gear, a set N of primary planetary pinions, a plurality of secondary planetary pinions, a compound drive shaft supporting each respective primary and secondary planetary pinion combination, a fixed ring gear interacting with the secondary planetary pinions, and a planetary carrier assembly disposed in rotatable combination with the compound drive shafts and operative to provide the output of the stacked compound planetary gear train to the main rotor shaft of the helicopter. The set N of primary planetary pinions includes a plurality N/2 of upper primary planetary pinions and a plurality N/2 of lower primary planetary pinions. The upper and lower primary planetary pinions are disposed in a staggered, biplanar relationship wherein each upper primary planetary pinion overlaps the immediately adjacent lower primary planetary pinions. The stacked compound planetary gear train functions as the third stage reduction gearing in the upgraded powertrain system which includes input modules for receiving the increased horsepower output of an augmented powerplant system. The input modules include first stage reduction gearing for coupling power from the input modules to a main transmission assembly gearing. Second stage reduction gearing of the main transmission assembly couples power to the stacked compound planetary gear train to drive the sun gear thereof.