Integrally cast vane and shroud stator with damper

An integrally cast stator for an axial flow gas turbine engine including an annular array of vanes integrally connected at their outer ends to an outer shroud and integrally connected at their inner ends to an inner shroud;

• said inner shroud having a forward edge and a rearward edge;
• an inwardly extending radial flange integrally connected to the inner shroud;
• a cylindrical flange extending from the radial flange and being integrally connected adjacent the inner end of the radial flange;
• said inner shroud, radial flange and cylindrical flange forming an annular C-shaped channel;
• an annular C-shaped spring damping device having inner and outer annular arms;
• said inner and outer annular arms having an inner and outer surface;
• said annular C-shaped spring damping device having a relaxed position where the inner and outer surfaces of the C-shape are spaced apart at one point a distance greater than the distance between the inner shroud and the cylindrical flange of the annular C-shaped channel;
• said annular C-shaped spring damping device being located in said annular C-shaped channel;
• said annular C-shaped spring damping device having said inner surface of said inner annular arm fixed to said cylindrical flange;
• said annular C-shaped spring damping device having said outer surface of said outer annular arm biased against said inner shroud providing a preload on said inner shroud to obtain a desired frictional force level.

A method of forming an integrally cast stator for an axial flow gas turbine engine having a damper including:

• (1) casting a stator having an annular array of airfoils connected at their outer ends to an outer shroud and connected at their inner ends to an inner shroud;
• said inner shroud having a forward edge and a rearward edge;
• (2) casting integrally therewith an inwardly extending radial flange connected to the inner shroud with a cylindrical flange extending from the radial flange adjacent its inner end;
• said inner shroud, radial flange and cylindrical flange forming an annular C-shaped channel;
• (3) forming an annular C-shaped spring damping device having outer surfaces for placing in the annular C-shaped channel;
• said annular C-shaped spring damping device having a relaxed position where the outer surfaces of the C-shape are spaced apart a distance greater than the distance between the inner shroud and the cylindrical flange of the annular C-shaped channel;
• (4) compressing the annular C-shaped spring damping device and placing it in the annular C-shaped channel;
• (5) fixing the inner arm of the spring damping device to the cylindrical flange with the outer arm being biased against the inner surface of the inner shroud;
• said spring damping device providing a preload to obtain a desired frictional force level.