| 摘要 |
PROBLEM TO BE SOLVED: To cause a spindle to collide with a supporting piece so as to offset oscillation, by causing the natural oscillation frequency of a collision damper unit including a leaf spring and the spindle to coincide with the oscillation frequency of the supporting piece in a focusing direction. SOLUTION: A collision damper unit 10 is provided to protrude in parallel along a focusing direction with respect to a supporting piece 2b of a body portion 2a. Such collision damper unit 10 includes a leak spring 10a and a spindle 10b provided in an integral manner at the distal end of the leaf spring so that the collision damper unit 10 may collide with and move away from the supporting piece 2b at the time of oscillation. The natural oscillation frequency of the collision damper unit 10 is caused to coincide with the oscillation frequency of the supporting piece 2b in the focusing direction, by adjusting the spring constant of the leaf spring 10a and the weight of the spindle 10b. In addition, a portion where the supporting piece 2b collides with the collision damper unit 10 is treated by wear-resistant processing. When the supporting piece 2b oscillates in the focusing direction at the time so operation, the collision damper unit 10 oscillates at the same frequency as that of the supporting piece 2b and with the opposite phase, and the spindle 10b collides with the supporting piece 2b, thus offsetting the oscillation. |
