Variable geometry turbine

摘要

A variable geometry turbine comprises a turbine wheel supported in a housing for rotation about a turbine axis with an annular inlet passageway defined between a radial face of a movable nozzle ring and a facing wall of the housing. The nozzle ring is movable along the turbine axis to vary the width of the inlet passageway. A substantially annular rib is provided either on the face of the nozzle ring (such that the minimum width of the inlet passageway is defined between the rib and the facing wall of the housing) or on the facing wall of the housing (such that the minimum width of the inlet passageway is defined between the rib and the nozzle ring).