VARIABLE-GEOMETRY TURBOCHARGER

摘要

An object is to is to reduce a leakage flow by reducing a clearance between an end surface of a nozzle vane, forming a variable nozzle mechanism of a variable geometry turbocharger, and a wall surface facing the end surface, and prevent the nozzle vane from being stuck due to contact of the end surface. A variable geometry turbocharger includes a nozzle shaft 49 which protrudes on one of the both end surfaces 58 of a nozzle vane 45 and rotatably supports the nozzle vane 45, a shaft hole 53 in which the nozzle shaft 49 fits with a gap in between, a distal end surface 57 of the nozzle vane with which a clearance is reduced when the nozzle vane 45 which has received exhaust-gas pressure is inclined toward an inner diameter side due to a fitting gap formed between the shaft hole 53 and the nozzle shaft 49 fit to each other, the clearance being formed between the distal end surface 57 and a wall surface 59a of another one of the parallel walls, and a clearance reduction promotion portion 65 which promotes reduction of the clearance with an increased inclination angle of the distal end surface 57 or an increased exhaust-gas-affected surface of the nozzle vane 45.