Turbo Machine, Compressor Impeller Used for Turbo Machine, and Method of Manufacturing Turbo Machine

摘要

A turbocharger as a turbo machine includes: a compressor impeller ( 13 ) having a projected portion ( 19 ) at a center of a rear surface; a drive shaft ( 15 ) connected to a bottomed coupling hole ( 20 ) provided in the projected portion ( 19 ) of the compressor impeller ( 13 ) through interference fit only; and a sleeve ( 30 ) with a cylindrical portion ( 33 ) connected to the outer peripheral portion of the projected portion ( 19 ) of the compressor impeller ( 13 ) by fitting only. The sleeve ( 30 ) is formed of a material whose coefficient of linear expansion is smaller than that of the compressor impeller ( 13 ). Accordingly, even when the coupling hole ( 20 ) in the projected portion ( 19 ) undergoes thermal expansion and the diameter of the coupling hole ( 20 ) increases, a connection between the drive shaft ( 15 ) and the coupling hole ( 20 ) can be prevented from being loosened since the radial increase thereof is suppressed by the cylindrical portion ( 33 ). Thus, the state of the connection thereof can be well maintained.