| 摘要 |
PROBLEM TO BE SOLVED: To improve the gain margin by reducing the resonance magnification of high order resonance, and to reduce the resonance magnification for the first order proper oscillation by providing the function of a magnetic damper. SOLUTION: A weight body 16 consisting of a magnetic body is buried in the magnetic flux distribution intensity center (magnetic flux strongest distribution part) in the focusing direction of a magnetic circuit consisting of magnets 3a, 3b, and so forth or an air-core part 15 of tracking coils 8a and 8b installed in the vicinity position thereof. Because the counter force for pulling the weight body 16 consisting of the magnetic body back to the magnetic flux distribution intensity center of the magnetic circuit thereby acts when a forced displacement arises in the focusing direction, the weight body which has usually contributed to only the damping effect against the high order resonance as a mass damper can be also used as the magnetic damper against the first order proper oscillation in the focusing direction.
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