| 摘要 |
[Problem] To decrease the clearance between edge surfaces of a nozzle vane that is part of a variable nozzle mechanism in a variable-geometry turbocharger and wall surfaces facing said edge surfaces, thereby preventing leakage flows, and to prevent the nozzle vane from contacting side edge surfaces and sticking, even if thermal deformation has occurred. [Solution] This variable-geometry turbocharger is characterized by the provision of a nozzle axle (49), an axle hole (53), a nozzle-vane tip surface (57), and a clearance-reduction magnification part (65). The nozzle axle (49) protrudes from one edge surface (58) of a nozzle vane (45) and fits into the axle hole (53), leaving a gap but rotatably supporting the nozzle vane (45). As a result of the gap left when the nozzle axle (49) is fitted into the axle hole (53), upon being subjected to exhaust-gas pressure, the nozzle vane (45) tilts inwards, thereby reducing the clearance between the nozzle-vane tip surface (57) and the surface (59a) of a parallel wall. The clearance-reduction magnification part (65) further decreases said clearance by increasing the tilt angle of the nozzle-vane tip surface (57) or the exhaust-gas profile area of the nozzle vane (45). |
