| 摘要 |
PROBLEM TO BE SOLVED: To not only realize reduction of driving noise and reduction of backlash with a simple configuration but also allow restoration even after collision with a fixed member. SOLUTION: A projecting part of a nut 3 is energized toward a rotation stop part 1a by providing a torsion spring 9 having a function of a compression spring between the nut 3 and a reception surface 1d for a frame of a third group. Since the projecting part of the nut 3 is not separated from the rotation stop part, tapping by the nut 3 does not occur to realize very quiet driving noise. The backlash is reduced because of no play in a rotating direction of the nut 3 and a lens frame. COPYRIGHT: (C)2005,JPO&NCIPI
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