SUPERCHARGER

摘要

A turbocharger for an automotive vehicle is comprised of a rotatable shaft having a cup-shaped section to which an axial projection of a turbine wheel is fitted under a shrinkage fit. The rotatable shaft is rotatably supported by ball bearings. A nut is screwed on the rotatable shaft in a manner to clamp the ball bearings together with a compressor wheel between it and the cup-shaped section. The inner race of the ball bearing on the turbine wheel side is in axially tight contact with an abutting surface formed in the rotatable shaft. In this arrangement, a setting is made to safisfy the following formala: l /P >/= 0.002 where l is a distance (mm) in the rotatable shaft, between a bottom inner surface of the cup-shaped section and the abutting surface; and P is an axial tensile force developed by screwing up the nut in the direction of the cup-shaped section.