Patent attributes
Providing a turbine rotor in which the rotational inertia of the turbine rotor can be reduced without changing the geometry of the blade part, whereas the turbine rotor is provided with the rear side surface so that the stress concentration appearing at the root part regarding the hub part on the rear surface side is constrained in order that the strength and the durability of the turbine rotor can be enhanced. A turbine rotor that comprises a hub part 9 connected to a rotor shaft 19 and a plurality of blade parts 11 formed around the outer periphery of the hub part 9, the hub part and the blade parts being integrated into one piece, wherein the diameter of the hub part 9 around the rotation axis L of the rotor shaft 19 gradually increases along the rotation axis direction toward a rear side surface 7 on an end side regarding the rotation axis direction; an annular recess 21 is formed annularly around the rotation axis as a rotation center line, on the side of the rear side surface 7 of the hub part 9; the cross-section of the annular recess whose plane includes the rotation axis is configured with a part of the major arc C of an oval shape or an egg shape, the major arc C being formed so that the oval shape or the egged shape is divided by the major axis b as a symmetrical axis of the oval shape or the egged shape; and, the major axis b is placed in the rear side surface 7.
