| 摘要 |
PURPOSE:To prevent the unbalance of an armature shaft by providing a hole in a position cancelling the eccentricity of the armature shaft due to the eccentric part of a core sheet fitted into the armature shaft. CONSTITUTION:The core 20 of an armature shaft 3 is formed by laminating a core sheet (CS) 5 and pressed into the armature shaft (AS) 7 for fixation. A hole 21 is provided in a plurality of core sheets (CS) 5 by punching it with press work or the like. The eccentric part 8 of the armature shaft (AS) 7 causes eccentricity downward on the basis of the central axis of the armature shaft (AS) 7 in a static condition. At that time, a hole 21a which is formed by punching the respective core sheets (CS) 5 in the eccentric direction due to the eccentric part 8, is provided to avoid eccentricity. Thereby, the center of gravity in the direction of the central axis of the armature shaft (AS) 7 and the armature core 20 can be moved upward. A hole 21b is provided by a similar method to the hole 21a in the position apart from the eccentric part 8 as compared with the hole 21a for the balance at the time of the rotation of the armature sheet (AS) 7.
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