Planetary gearbox

摘要

A planetary gearbox for a marine propulsion unit or an earth moving unit, comprises a hollow wheel gear 1, two or more planet gears 2, and a sun gear 3. One or more of the hollow wheel gear, two or more planet gears, and sun gear comprise a plurality of teeth 4 that have been superfinished to a final surface roughness of 0.25 micron or less. The resulting gearbox is able to operate in a regime of full elastohydrodynamic lubrication (EHL) even at very low-speeds and under high-load conditions.