| 摘要 |
PROBLEM TO BE SOLVED: To provide a diaphragm mechanism for a camera such that constituent components of a motor are individually assembled on a diaphragm base plate and a rotor is able to control a diaphragm diameter by smoothly and stably rotating. SOLUTION: A base plate 1 has a cylindrical part 1i which is open at one end and closed at the other end and a rotor shaft 11 is stood therein. The rotor shaft 11 has three bearing ring parts 11a, 11b, and 11c and also has ring-shaped grooves 11d, 11e, and 11f formed on its circumferential surface, and is filled with lubricating oil such asαolefin based oil and grease. Further, a rotor 12 has a cylindrical permanent magnet 12a and an output gear 12b, the peripheral surface of the permanent magnet 12a is arranged opposite magnetic pole parts of yokes 9 and 10, and a bearing hole formed in the center of rotation is brought into contact with only peripheral surfaces of the bearing ring parts 11a, 11b, and 11c. Consequently, the rotor 12 smoothly rotates to preferably rotate a diaphragm driving ring 7 through a parent-child gear 13. COPYRIGHT: (C)2004,JPO&NCIPI
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