Turbocharger having a preloaded bearing assembly

Claim 1

A turbocharger comprising: a main housing having a throughbore, a tubular bearing carrier coaxially positioned within said throughbore, means for securing said bearing carrier to said housing against axial movement, a shaft extending through said bearing carrier, said shaft having a turbine at one end and a compressor at its other end, a pair of bearing assemblies for rotatably mounting said shaft to said bearing carrier, each bearing assembly comprising an inner race, an outer race, and bearing elements entrapped between said races, said bearing assemblies being axially spaced from each other and contained between said turbine and said compressor, means for securing said inner races against axial movement to said shaft, means contained between said bearing assemblies for urging the outer races of said bearing assemblies axially away from each other, wherein said bearing carrier includes a radially inwardly extending flange and wherein said urging means comprises: a first annular spacer positioned around said shaft and having an outer end in abutment with an inner axial end of the outer race of one bearing assembly, a second annular spacer positioned around said shaft and having an outer end in abutment with an inner axial end of the outer race of the other bearing assembly, said second spacer having an inner axial end in abutment with one axial end of said flange, and means for resiliently urging said first annular spacer and the other axial end of said flange away from each other whereby said resilient urging means automatically positions each said bearing assembly at a predetermined axial position with respect to said flange.