US Patent 11578611 Variable guide vane assembly and bushings therefor

A gas turbine engine has: an annular gaspath extending around a central axis and defined between a first casing and a second casing; and a variable guide vane (VGV) assembly having: variable guide vanes, the variable guide vanes having airfoils extending between first and second stems at respective first and second ends of the airfoils, the variable guide vanes rotatable about respective spanwise axes; a unison ring rotatable about the central axis, the unison ring operatively connected to the variable guide vanes for rotating the variable guide vanes about the respective spanwise axes, and a segmented bushing having bushing segments circumferentially distributed around the central axis, the bushing segments radially supported and axially constrained by the first casing, the unison ring rollingly engaged to the first casing via the bushing segments, the unison ring axially and radially constrained to the first casing via the bushing segments.