| 摘要 |
PURPOSE:To enhance a bending rigidity at a connected portion to prevent reduction in a dangerous speed and stabilize an axial system against an external force, by boring a connection hole through a runner cone of a high-pressure stage runner, inserting a mount portion of a lower shaft into the hole to weld same. CONSTITUTION:A main shaft 1 of a water turbine is constituted of an upper shaft 2 and a lower shaft 3, and a flange 2a formed at a lower end of the upper shaft 2 is tightly connected to a high-pressure stage runner by a securing bolt 5. A low-pressure runner 6 is connected to the lower shaft 3 by a bolt 7. A mount portion 3a of the lower shaft 3 is fitted in a connection hole 15 formed through a runner cone of the high-pressure stage runner 4, and is welded to the hole along a weld bead 16 at an outer circumferential edge of an end of the mount portion 3a. Further, a runner cone of the high-pressure stage runner 4 is welded to the lower shaft 3 along a weld bead 17. Thus, a bending rigidity at a connected portion may be enhanced to prevent reduction in a dangerous speed, and an axial system may be stabilized against an external force. |
