DYNAMIC VIBRATION ABSORBER

PURPOSE:To permit the use of a dynamic vibration absorber (dynamic damper) installed for absorbing the vibration having a frequency component, even in a system in which the characteristic frequency of the system varies or the excitation frequency varies. CONSTITUTION:Electromagnets 8 and 9 are arranged, keeping a certain internal from the magnetic pole of a permanent magnet 5, and either the permanent magnet 5 or the electromagnets 8 and 9 is fixed on a vibration suppressed body 13, and the other can be shifted in the direction for varying the interval between the magnetic poles. The shift of the vibration suppress body 13 and the relative shift between the electromagnets 8 and 9 and the permanent magnet 5 are detected by the displacement meters 14 and 7. These detection signals are inputted into a control circuit 29 through a signal amplifier 15, and the optimum excitation current is allowed to flow in the electromagnets 8 and 9 through an amplifier 16 by the control circuit 29.