| 摘要 |
<p>PURPOSE:To prevent generation of abnormal vibration of a cover plate and obtain the divided runner, easy to manufacture, stable dynamically and inexpensive by providing balance holes at places near a radial rib whereat the deformation of the cover plate is small. CONSTITUTION:The balance holes 12a, 12b are provided at the circumferential positions near the radial ribs 8a, 8b forming the side wall of a space 9. A distance between the ribs 8a, 8b on the same radius is three times of the distance between the balance holes 12a, 12b and the radial ribs 8a, 8b on the radial line. According to this formation, the displacements of the cover plate at the positions provided with the balance holes are small, therefore, moving amount of water in the inside and outside of the cover plate through the balance holes, which is synchronized with the vibration displacement of the cover plate, is small and the abnormal vibration due to self-exciting vibration will never be generated easily</p> |
