Stator assembly

A gas turbine engine comprising:

• an outer shroud;
• a stator assembly coupled to the outer shroud, the stator assembly including an endless case coupled to a lug and defining an axis, the case coupled to a plurality of stator segments for forming an endless ring of stator segments, each stator segment including a shroud coupled to the case and a radially inwardly extending vane, the shroud of each stator segment including first and second opposing side edges, each of which engages an adjacent stator segment;
• the plurality of stator segments includes an anti-rotation stator segment that is coupled to the lug, a neighbor stator segment disposed adjacent to the anti-rotation stator segment and a plurality of middle stator segments;
• the shroud of the anti-rotation stator segment is coupled to a pair of upper aft hooks and a single lower aft hook extending in a facing spaced relationship with respect to the pair of upper aft hooks, the shroud of the anti-rotation stator segment including a slot extending from a first end located at a distal end of the single lower aft hook and between the pair of upper aft hooks and to a second end located past the pair of upper aft hooks and proximate to a forward hook of the anti-rotation stator segment and wherein the slot is configured to accommodate the lug therein;
• the first side edges of the middle stator segments being non-linear and the second side edges of the middle stator segments being non-linear but shaped for abuttingly engaging the first side edge of an adjacent middle stator segment;
• the first side edge of the anti-rotation stator segment being linear, the second side edge of the neighbor stator segment being linear for abuttingly engaging the first side edge of the anti-rotation stator segment;
• the second side edge of the anti-rotation stator segment being non-linear and shaped to abuttingly engage the first side edge of an adjacent middle stator segment, the first side edge of the neighbor stator segment being non-linear and shaped to abuttingly engage the second side edge of an adjacent middle stator segment;
• the plurality of stator segments forming a plurality of stator segment clusters, each stator segment cluster including an anti-rotation stator segment, a neighbor stator segment and a plurality of middle stator segments disposed therebetween.

A method for forming a stator stage of a gas turbine engine, the method comprising:

• providing an endless case coupled to a plurality of lugs and defining an axis, the case including a forward portion and an aft portion that extend towards each other to form forward and aft pockets respectively;
• coupling the one of the forward or aft portions to an outer shroud of the engine;
• providing a plurality of stator segment clusters, each stator segment cluster including an anti-rotation stator segment, a neighbor stator segment and a plurality of middle stator segments disposed therebetween, each anti-rotation stator segment, neighbor stator segment and middle stator segment including a shroud and a radially inwardly extending vane, the shroud of each anti-rotation, neighbor and middle stator segment including first and second opposing side edges for engaging an adjacent stator segment, the first side edges of the middle stator segments being non-linear and the second side edges of the middle stator segments being non-linear but shaped for abuttingly engaging the first opposing side edge of an adjacent middle stator segment, the first side edges of the anti-rotation stator segments being linear, the second side edges of the neighbor stator segments being linear for abuttingly engaging the first side edge of one of the anti-rotation stator segments, the second side edges of the anti-rotation stator segments being non-linear and shaped to abuttingly engage the first side edge of an adjacent middle stator segment, the first side edge of the neighbor stator segment being non-linear and shaped to abuttingly engage the second side edge of an adjacent middle stator segment;
• axially inserting the anti-rotation stator segment of one cluster into the case at one of the lugs to couple the anti-rotation stator segment to the lug, the shroud of the anti-rotation stator segment being coupled to a pair of upper aft hooks and a single lower aft hook extending in a facing spaced relationship with respect to the pair of upper aft hooks, the shroud of the anti-rotation stator segment including a slot extending from a first end located at a distal end of the single lower aft hook and between the pair of upper aft hooks and to a second end located past the pair of upper aft hooks and proximate to a forward hook of the anti-rotation stator segment and the slot being configured to accommodate the lug therein;
• axially placing a middle stator segment next to the anti-rotation stator segment so the first side edge of the middle stator segment abuttingly engages the second side edge of the anti-rotation stator segment;
• repeatedly and axially placing middle stator segments into the case so the first side edge of a succeeding middle stator segment engages the second side edge of a preceding middle stator segment until a gap exists between a succeeding middle stator segment a succeeding lug;
• axially inserting the neighbor stator segment into the gap;
• axially inserting another anti-rotation stator segment into the case to couple said another anti-rotation stator segment to the succeeding lug and so the second side edge of the neighbor stator segment engages the first side edge of said another anti-rotation stator segment.