Web Services Choreogra-phy Interface

A drive train is provided with a planetary gear system including sun, planet, and internal ring gears, side plates abut the gears with the side plates being provided with oil passages aligned with teeth of the gears. The oil passages are spaced around the periphery of the gears out of alignment with a meshing point between gears. The gears are housed in an inner housing which is substantially completely filled with oil delivered from a reservoir by gravity flow. The gears advantageously lie in a single plane for ease of sealing and manufacture. Oil passing between the gears serves to cool the gears and is squeezed between meshing teeth to provide a hydraulic resistance and thus partially lock the gears.