| 摘要 |
PURPOSE:To prevent a tenon from being fractured by gradually reducing a cross-sectional area of a bucket coupling member in a width direction thereof from buckets adjoining circumferentially toward a central portion among the buckets, and reducing centrifugal force and stress applied to a bucket coupling member. CONSTITUTION:A shroud plate 4 is assembled onto the outer peripheral surface of a plurality of buckets 1 having a tenon 2 provided at an end part on the outer peripheral side thereof as a bucket coupling member having a hole fitting to the tenon 2. Thereupon, the shroud plate 4 is adapted to have a prescribed wall thickness and a width gradually reduced from the buckets 1 adjoining circumferentially toward a central portion 4a among the buckets forming a circular arc-shape. Namely, the shroud plate 4 has a maximum width B at their portions superposed on the end part 4b on the outer peripheral side thereof, the width being gradually reduced toward the central portion 4a among the buckets. In addition, the central portion 4a has an amount of indentation delta1 at the side of a steam inlet and an amount of indentation delta2 at the side of a steam outlet respectively being shortened, and has a minimum width A at the central portion 4a among the buckets. |
