Variable-vane assembly having fixed guide pins 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 guide pins for the unison ring are inserted into apertures in the nozzle ring and are rigidly affixed therein such that the guide pins are non-rotatably secured to the nozzle ring with a guide portion of each guide pin projecting axially from the face of the nozzle ring. Each guide portion defines a shoulder radially overlapping the inner edge of the unison ring such that the unison ring is restrained by the guide pins against excessive movement in both radial and axial directions.

主权项

1. A variable-vane assembly for a turbocharger, comprising:
a nozzle ring having opposite first and second faces and having a plurality of circumferentially spaced-apart first apertures each extending axially into the first face and a plurality of circumferentially spaced-apart second apertures each of which extends axially from the first face to the second face; a plurality of vanes having respective axles received into the second apertures from the second face of the nozzle ring and being rotatable in the second apertures such that the vanes are rotatable about respective axes defined by the axles, a distal end of each axle projecting out from the respective second aperture beyond the first face; a plurality of vane arms respectively affixed rigidly to the distal ends of the axles, each vane arm having a free end; a unison ring having a radially inner edge defining a plurality of recesses therein that respectively receive the free ends of the vane arms, the unison ring being positioned coaxially with the nozzle ring with a face of the unison ring opposing the first face of the nozzle ring, the unison ring being rotatable about an axis of the nozzle ring so as to pivot the vane arms, thereby pivoting the vanes in unison; protrusions integrally formed on the nozzle ring and extending from the nozzle ring and contacting the unison ring, so as to axially space the first face of the nozzle ring from the opposing face of the unison ring by a first axial distance; and a plurality of guide pins located radially inward of the radially inner edge of the unison ring, the guide pins each being inserted into a respective one of the first apertures in the nozzle ring and being rigidly affixed therein such that the guide pins are non-rotatably secured to the nozzle ring with a guide portion of each guide pin projecting axially from the first face of the nozzle ring, the guide portion of each guide pin having a shank and defining a shoulder axially spaced from the first face of the nozzle ring by a second axial distance greater than the first axial distance, the shoulders radially overlapping the radially inner edge of the unison ring, whereby the protrusions and the shoulders cooperate to constrain axial movement of the unison ring and the shanks constrain radial movement of the unison ring.