| 摘要 |
PURPOSE:To prevent a threaded part from breaking due to fatigue, by dispersing bending moment, which acts on a moving blade shaft, to be prevented from being transmitted to the threaded part of the moving blade shaft, by means of a pair of concentric ring-shaped tightening members having a tapered surface aligned and brought into contact with each other. CONSTITUTION:A hub fitted to a rotary shaft provides in a rim part 24A a moving blade-shaft insertion hole 25 extending in a radial direction. A moving blade shaft 27 is inserted into this insertion hole 25. And the moving blade shaft 27, protruded to a reverse part 24B of the rim part 24A, forms a smooth round bar part 27B and a threaded part 27C successively with a step difference. The round bar part 27B assembles a pair of concentric ring-shaped tightening members 22, 23 having a tapered surface reducing its contour toward the point end part of a moving blade. And the moving blade is tightened by a tightening nut 28. The tightening members 22, 23 are constituted so as to tighten the moving blade by the wedge action in accordance with a level of centrifugal force acting on the moving blade.
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