| 摘要 |
In the feed screw device, both end parts of a feed screw are movably supported through cushioning members, and an inertia force of the feed screw after a movable member moved by the feed screw has collided against a stopper is absorbed by a movement in an axial direction of the feed screw, so that an impact at a drive end can be softened. When the guide part comes into contact with the stopper and a projection lens barrel is positioned at an upper end of a moving stroke, an upward movement of the projection lens barrel is stopped, but a motor is not stopped and is in a rotating state. A driving power of the motor is continuously transmitted to the feed screw, but since an upward movement of a nut member is restricted, a force of a downward movement is given from the motor to the feed screw. Then, the feed screw moves downward against an urging force of a spring. By this action, an impact force at the time when the guide part comes into contact with the stopper is softened.
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