Patent ID: 7647772
Filing Date: 2010-01-19
Classification: F01D,F05D

Abstract:
1. A variable geometry exhaust turbine comprising: a turbine housing; a vane base; a vane side space and a command side space defined in part by opposite sides of the vane base wherein a pressure differential forms between the vane side space and the command side space during operational transients; a plurality of vanes set in the vane base wherein each vane comprises a post extending from the command side space to the vane side space, that defines a pivot axis, wherein the vane base receives each post to allow for pivoting of a vane about its pivot axis and wherein the pressure differential forms in a direction of the pivot axis; and an insert positioned at least partially between the turbine housing and the vane base wherein the insert comprises a nitrided surface that fronts the plurality of vanes, wherein contact exists between the vanes and the nitride surface due to formation of the pressure differential during operational transients, wherein the contact and the pressure differential cause vane actuation hysteresis and wherein the nitrided surface of the insert reduces friction between the vanes and the insert and reduces the vane actuation hysteresis.