TURBINE ROTOR BLADE

摘要

Disclosed is a turbine rotor blade provided with the shape of the back surface of the rotor blade which while reducing the inertia moment of the rotor blade without changing the shapes of the blades, suppresses the occurrence of stress concentration at the root of the back surface of the rotor blade, thereby improving strength and durability. The turbine rotor blade (1) is obtained by integrally forming a shaft-shaped hub (9) connected with a rotary shaft (19) and the plurality of blades (11) formed in the periphery of the hub (9). The hub (9) has a shape gradually increasing in diameter toward the back surface (7) which is one end side thereof in the direction of the rotary shaft. In the back surface (7), an annular concave (21) is formed around the center line (L) of the rotary shaft (19). The cross-section shape of the concave (21) in the direction of the rotary shaft is formed of a long circular arc (C) of an ellipse obtained by dividing a curve shape symmetrical about the long axis such as an elliptical shape and an egg shape by the long axis, and formed such that the position of the long axis (b) matches with the back surface (7).