| 摘要 |
PURPOSE:To enable to reduce the size of a motor by providing a pyramid coincidence center hole on the end face of a rotational shaft as a cutting and grinding center guide. CONSTITUTION:A hollow shaft 11 drien by a prime mover 14 is supported by a bearing 12 through a pulley 13 on the same center as a shaft 2 of a motor to be machined. A center shaft 15 is projected in the shaft 11 from the shaft 11 toward the motor, and a pyramid 16 is provided at the end of the shaft 15. Further, a large-diameter stepping portion 17 is provided at the portion projected from the shaft 11 of the shaft 15, a coiled spring 18 is inserted between the portion 17 and the end face of the shaft 11, the pyramid 16 of the shaft 15 is pressed to the center hole 19 formed at the end of the rotational shaft of the motor to intrude the edge of the pyramid 16 to the hole 19. Thus, it is not necessary to project the shaft from a motor casing so as to chuck the shaft to be machined, thereby reducing the size of the motor. |
