Patent ID: 7575192

Claim:
A transmission system for use with a microturbine engine having an output shaft, the transmission system comprising: an input shaft operably coupled to the output shaft of the microturbine engine; and a gear train including a first gear and a second gear that interface to one another, the first gear fixed relative to said input shaft and rotating in the same direction as the input shaft, the second gear fixed relative to a counter-rotating shaft and rotating in the opposite direction of said input shaft, wherein the first and second gears employ teeth with first-type and second-type opposite handed helix-angled surfaces, the first-type opposite handed helix-angled surfaces applying axial forces to said input shaft during a normal operation mode where the microturbine engine drives the transmission system and the second-type opposite handed helix-angled surfaces applying axial forces to said input shaft during a start up operation mode where a generator drives the transmission system and microturbine engine, said first-type and second-type opposite handed helix-angled surfaces on respective normal drive sides and normal coast sides of the teeth, and said axial forces pushing the input shaft toward the output shaft of the microturbine engine.