| 摘要 |
PROBLEM TO BE SOLVED: To obtain a motor actuator which prevents a backlash inside a hole used to bear a cylindrical shaft and by which an object to be driven can be driven with good accuracy by a method wherein at least three protruding bodies used to stop a rotation are installed integrally at the inner wall of the cylindrical shaft at equal intervals in the circumferential direction. SOLUTION: A slipping stop part 49 in which a plurality of protruding bodies 49A are formed along its inner circumference is formed at the inner wall 48B of a cylindrical shaft 48. The slipping stop part 49 is molted integrally as a thick-wall step part at the inside of the cylindrical shaft 48, and the protruding bodies 49A are installed at equal intervals along the inner circumference of the slipping stop part 49. In addition, the protruding bodies 49A are formed respectively to be V-protrusion-shaped, their number is eight, and the wall thickness in the radial direction of the circumferential wall of the cylindrical shaft 48 as a whole is changed regularly along its circumferential direction. That is to say, thin-wall parts and thick-wall parts are arranged equally along the circumferential direction. Consequently, when the size of a bearing hole is decided to be the size of a true circle indicated by a dotted line, the cylindrical shaft 48 can be borne stably without any backlash.
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