| 摘要 |
PURPOSE:To reduce the internal stress produced in blanking the circumference of an inner diam. of iron core and to improve the accuracy of the inner diam. of iron core, by providing the blanking stage of a small diam. smaller than an inner-diam. blanking dimension before the stage of blanking the inner diam. of iron core. CONSTITUTION:A small-diam. blanking part 16 is blanked before blanking an inner-diam. blanking part 13 of iron core. Then the deformation due to the internal stress, accumulated in a steel plate by a slot blanking part 12, is absorbed by an A part, and the change of an inner diam. dimension produced as the time of blanking the inner-diam. blanking part 13 can be restricted to a minimum. |
