VARIABLE GEOMETRY TURBOCHARGER

摘要

A variable geometry exhaust gas turbocharger comprises: a turbine rotor 26 including a rotating shaft 24 and a turbine wheel 12; a bearing housing 20 accommodating a bearing unit 22; a turbine housing 10 accommodating the turbine wheel rotatably and having formed an annular turbine scroll part 16 in which exhaust gas flows; and a variable geometry mechanism 40 provided in an annular nozzle part 18 to guide the exhaust gas flowing in the turbine scroll part into the turbine wheel; wherein the variable geometry mechanism 40 comprises: a nozzle vane 42 protruding, in a state of being unable to rotate, from at least one of a shroud side or a hub side of the nozzle part toward the nozzle part; an annular nozzle wall 44 configured to be movable forward and backward from the hub side toward the shroud side or from the shroud side toward the hub side of the nozzle part, and configured to permit a nozzle width B of the nozzle part to be variable over all circumference; and a driving part 46 for moving the nozzle wall forward and backward.