MAINTAINING METHOD OF FATIGUE STRENGTH OF BLADE AND BLADE

摘要

PURPOSE: To relieve a stress exerted on the tip part of a blade by a method wherein a part of one or both of surfaces facing each other at an intersection part between the opposite faces and the central part of the tip part of a blade is chamfered. CONSTITUTION: A blade 20 comprises a base part; a front edge 24; a rear edge 26; and a body consisting of a protrusion-form front 27 and a recessed rear face 28, positioned facing each other, and a blade tip part 29. Chamfered parts 30 are formed approximately at an equal distance along the surfaces, positioned facing each other, of the blade tip part 29 and extending partially between the front edge 24 and the rear edge 26. By varying the angle ϕ of a chamfered surface and a distance 42 by which the chamfered surface is extended, equiliblium between the region of a desired blade tip part and reduction of a desired stress is controlled. This constitution relieves a concentration at an intersection between the body 22 of the blade 20 and the tip part 29.