Most industrial gear reducers rely on splash lubrication for their internal bearings and gears. Generally the gear housing is partially filled with lubricating oil and at least one rotating gear is partially submerged in the oil. During operation, the rotation of the partially submerged gear discharges oil radially, which then “splash” lubricates other internal gears, bearings and surfaces.

This method works well at moderate speeds if all locations requiring lubrication are well “splashed”. If any bearing or gear is not well splashed, premature failure results. Gearboxes installed with vertical output shafts often “starve” the upper output shaft bearing, especially when operated at low speed with reduced oil splash.

Grease is sometimes substituted for oil in small gearboxes as it will adhere somewhat to the gear and bearing surfaces. Internal bearings and gears are well greased at assembly and are generally classified as “lubed for life”, as there is no practical way to exchange the grease without complete disassembly of the gear reducer. Although the “greased at assembly” method provides adequate initial lubrication, over a relatively short period of time the grease does migrate away from the critical load bearing points within bearings and mating gears, thus rendering inadequate or zero lubrication. Furthermore, grease does not provide either the thermal transfer or wear debris flushing benefits of a liquid oil lubricated gear reducer.

Stainless Motors, Inc. has developed a patent pending internal positive pressure lubrication system which guarantees a continuous supply of lubricating oil to the vulnerable upper shaft bearing of vertically mounted reducers. The system utilizes the existing rotary motion of internal shafts or gears combined with a sinusoidal cam to drive a positive displacement oil pump whose output is then directed to the desired lubrication points. The pump works equally well regardless of the direction of input shaft rotation and is completely maintenance free.

The availability of adequate lubricating oil, even at very low speeds, greatly extends the operating life and load capacity of the internal gears and bearings. The attached drawing depicts a typical pump installed in a worm gear reducer with a vertical output shaft. This lubrication system is now a standard feature of all Stainless Motors, Inc. SBT series reducers and larger RA series reducers. The positive pressure lubrication system may be factory retrofitted into all previously produced SBT and larger RA reducers manufactured by Stainless Motors, Inc. over the last 15 years, providing all of the current design benefits at substantially reduced cost over outright replacement with a new reducer.