| 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.
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