VARIABLE-VANE ASSEMBLY HAVING FIXED AXIAL-RADIAL GUIDES AND FIXED RADIAL-ONLY GUIDES FOR UNISON RING

摘要

A variable-vane assembly for a variable nozzle turbine comprises a nozzle ring supporting a plurality of vanes affixed to vane arms that are engaged in recesses in the inner edge of a unison ring. The unison ring is rotatable about the axis of the nozzle ring so as to pivot the vane arms, thereby pivoting the vanes in unison. A plurality of radial-axial guide pins for the unison ring are inserted into apertures in the nozzle ring and are rigidly affixed therein such that the radial-axial guide pins are non-rotatably secured to the nozzle ring with a guide portion of each radial-axial guide pin projecting axially from the face of the nozzle ring. Each guide portion defines a groove for receiving the inner edge of the unison ring such that the unison ring is restrained by the radial-axial guide pins against excessive movement in both radial and axial directions.