Mechanically driven centrifugal air compressor with hydrodynamic thrust load transfer

Claim 1

A centrifugal air compressor adapted to be mechanically driven by an internal combustion engine and deliver air thereto for combustion, said compressor comprising a housing, an impeller shaft having an impeller at one end and a helical pinion gear at an opposite end, plain journal bearings supporting said impeller shaft at axially spaced locations in said housing, input means, a support shaft rotatably supporting said input means on said housing in parallel relationship with said impeller shaft, said input means including an internal helical ring gear meshing with said pinion gear, said input means further including a compressor pulley adapted to be driven by the crankshaft of an engine at increased speed by a belt driven by a pulley of larger diameter fixed to the engine crankshaft, a thrust bearing extending about said impeller shaft and mounted in said housing between said impeller and one of said plain journal bearings, a thrust ring mounted on said impeller shaft and engaging on one side with a thrust face of said thrust bearing and engaging on an opposite side with both said housing and said one plain journal bearing to axially locate said impeller shaft in said housing and wherein air pressure acting on said impeller from impeller operation imposes an axial tension load on said impeller shaft that is borne by said thrust face, said pinion gear and said impeller having the same lead direction so that said gears impose a substantial axial tension load on said impeller shaft in opposition to that imposed by air pressure from impeller operation to thereby effect a net axial load acting on said impeller shaft and borne by said thrust face that is substantially less than that imposed by the air pressure from impeller operation, said thrust face having a plurality of oil pockets opposite said thrust ring having a depth that gradually decreases from a deep end in the direction of thrust ring rotation, and passage means for delivering oil under pressure to said oil pockets to hydrodynamically transfer the net axial load on the impeller shaft from said thrust ring to said thrust face.