PURPOSE: To prevent occurrence of the cracking of a moving blade body and to provide prolonged life of a moving blade by a method wherein a U-shaped escape groove to prevent interference with a positioning member during movement of the moving blade is formed, and a blocking part is integrally formed to the end part on the opening side of the escape groove.
CONSTITUTION: A U-shaped escape groove 21b to prevent interference with a stopper head 25 during movement of a moving blade 20 is formed on the side reverse to a moving blade body 21, and a blocking part 21i to block an opening part is integrally formed on the opening side of the escape groove 21b. The moving blade body 21 forms a pair of center beams instead of a pair of conventional cantilever beams. A fastening force produced by a press-in, a shrinkage fitting, or a metal flow method is exerted in a direction, in which the blocking part 21i is compressed from both ends, for balancing. Bending moment exerted on the moving blade body 21 and in turn a residual stress produced at the bottom part of the escape groove 21b is sharply relieved. As a result, a residual stress is reduced, a crack is prevented from occurring, and a life of the moving blade 20 can be prolonged.
MORI KAZUAKI
HARASAKI YASUO
