Lubrication system for and method of minimizing heat rejection in gearboxes

Gearboxes having bearings, gears, splines, and seals have been provided with a continuous flow of lubricating and cooling oil supplied through orifice jet units having orifices of a size to preclude clogging by core sand remaining in the cast housing of a gearbox. This has resulted in excessive oil in the gearbox and excessive heat rejection. An improved lubrication system for minimizing heat rejection in gearboxes has the orifices of the orifice jet units sized to deliver only the required flow to the components in the gearbox and a filter is associated with each of the orifice jet units to preclude core sand entrained in the oil and of a size to block an orifice from reaching an orifice. The method of minimizing heat rejection embodies the determination of only that amount of lubricating and cooling oil flow required for the bearings, gear meshes, splines and seals in the gearbox and sizing the orifices accordingly.