| 摘要 |
PURPOSE:To suppress the run-out of the blade concerned to the order, which does not hinder cutting operation, and contrive to improve its working efficiency and prolong its service life by a method wherein a rotary board is produced by laminating unit sheets under the condition that bent part is formed over the whole circumference. CONSTITUTION:A rotary board 2 is produced by laminating formed sheets 10 and 12 as unit sheet to each other so as to be pasted together. The respective formed sheets 10 and 12 can be formed by pressing, for example. On respective sides, bent parts 14 and 16 are formed over the whole circumference to the outer periphery side, while bent parts 18 and 20 are formed over the whole circumference to the inner periphery side. When axially inward bending stress F1 is applied to the rotary board 2, rigidity, which is mainly developed by the bent parts 16 and 18, is obtained. When outward bending stress F2 is applied, rigidity, which is mainly developed by the bent parts 14 and 20, is obtained. Accordingly, run-out, which is larger than that based on minute ununiformity in manufacturing, is checked. Stress concentration is relaxed by the respective bent parts 14, 16, 18 and 20, resulting in suppressing the permanent strain of the rotary board 2 and ensuring the accuracy of the run-our of a blade for a long period of time and contriving to improve the workability and to prolong the service life of the blade. |
