| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a stator yoke for a stepping motor wherein an air-cored coil fit onto a pole tooth is not flawed by a burr formed on the outline of the pole tooth and it is possible to sharply bend the base portion of each pole tooth and ensure an erection height of each pole tooth. SOLUTION: The manufacturing method includes: a crushing step of pressing a crushing punch (not shown) against the surface 10a of a yoke formation portion 20 of a blank 10 and reducing the plate thickness t of a fan-shaped range, defined by an outline oblique side L to an inside oblique side L' in proximity to the inside thereof which comprises the outline of each pole tooth K in the surface 10a and the inside oblique side L' of an adjacent other pole tooth K, to t'(<t) to form a fan-shaped concaved surface H; a punching step of plunging a stamping punch (not shown) from the back surface 10b side to the surface 10a side to form the outline of each pole tooth K; and a bending step of plunging a bending punch (not shown) from the back surface 10b side to the surface side 10a to bend and erect each pole tooth K. COPYRIGHT: (C)2011,JPO&INPIT
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