| 摘要 |
A steam turbine blade in which the turbine blade has a blade root of the axially-inserted fir tree type and a larger number of turbine blades can be attached in a restricted outer peripheral region of a turbine rotor by arranging the blade root to be oriented in a direction forming a predetermined angle ± larger than 0° relative to the axial direction of the turbine rotor, and which can suppress peak stresses generated at the bottoms of notches formed in the blade root and a blade groove and also suppress fretting fatigue from being induced by contact between peak stress generating areas and areas opposed to the peak stress generating areas at the notch bottoms. Respective values of the angle ± and an angle ¸ formed between a plane perpendicular to an axis of the blade root and a plane parallel to contact portions of the hooks formed in the blade root and the blade groove are set to fall within a range specified by 500 ‰¥ ± x ¸ > 0, 90 > ¸ ‰¥ 39 and 90 > ± > 0. |
