Patent ID: 7117596

Claim:
A method of manufacturing an adjustable blade of a VGS turbocharger, the adjustable blade including a center-of-rotation shaft portion and a blade portion for adjusting a flow rate of exhaust gas, the turbocharger being operable to throttle the exhaust gas discharged from an engine at a relatively low flow rate to increase the velocity of the exhaust gas so that an exhaust turbine wheel of the turbocharger is rotated by energy of the increased-velocity exhaust gas and so that a compressor directly coupled to the exhaust turbine wheel feeds a larger amount of air into the engine than would be fed by natural suction, whereby a high output power of the engine is obtained at low rotational speeds, said manufacturing method comprising: providing a starting form of the adjustable blade, the starting form being made of a shaped metal material integrally having a blade portion forming section and a shaft portion forming section; rolling the shaft portion forming section of the shaped metal material until the shaft portion forming section has a diametrical thickness substantially equal to a diametrical thickness of the shaft portion of the adjustable blade so as to thereby form the shaft portion of the adjustable blade; rotatably fitting a fitting portion of the shaft portion of the adjustable blade into a receiving hole of a frame member positioned outside an outer periphery of the exhaust gas turbine wheel; and the fitting portion has a rolled part and a non-rolled part having a diameter smaller than a diameter of the rolled part, wherein said rolling of the shaft portion forming section comprises rolling only a portion of the shaft portion forming section of the shaped metal material corresponding to the rolled part of the fitting portion of the shaft portion.