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Vibration damping apparatus

  • US 8,047,512 B2
  • Filed: 04/04/2007
  • Issued: 11/01/2011
  • Est. Priority Date: 04/14/2006
  • Status: Expired due to Fees
First Claim
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1. A vibration damping apparatus actively damping vibration of a vibration source by adding vibration to the vibration source, comprising:

  • a vibrational state detecting means for detecting a vibrational state of the vibration source; and

    a vibrator including;

    a magnetic pole;

    a coil provided so as to intercept magnetic flux formed by the magnetic pole; and

    a controlling means electrically connected to the coil, the vibrator adding vibration to the vibration source by controlling a current-supplied state of the coil to vibrate the coil and the magnetic pole relative to one another,wherein the controlling means selectively switches between a vibration generating mode and a regenerative mode based on the vibrational state of the vibration source, the vibration is added to the vibration source to damp the vibration of the vibration source in the vibration generating mode, and regenerative current is caused by an electro motive force generated at the coil by the vibration of the vibration source to flow into a regenerative resistor in the regenerative mode, the regenerative resistor being electrically connected to the controlling means;

    wherein the vibration source has a rotation machine, the vibrational state detecting means detects a number of revolutions of the rotation machine as the vibrational state, the controlling means switches to the regenerative mode when the number of the revolutions is in a predetermined set range;

    wherein the vibration generating mode has a vibration generation suppressing mode and a vibration generation implementing mode, the vibration generation suppressing mode is performed when the number of revolutions is in a first boundary range and in a second boundary range, the first boundary range extends upward from an upper boundary of the predetermined set range and the second boundary range extends downward from a lower boundary of the predetermined set range,the vibration generation implementing mode is performed when the number of revolutions is in a first implementing range and in a second implementing range, the first implementing range extends upward from an upper boundary of the first boundary range and the second implementing range extends downward from a lower boundary of the second boundary range,the controlling means conducts first PWM control in the vibration generation implementing mode and conducts second PWM control in the vibration generation suppressing mode, the first PWM control sets a time period for supplying the current to the coil in accordance with a first relationship in which the time period for supplying the current to the coil becomes longer as the vibration of the vibration source based on a detection result of the vibrational state detecting means becomes larger, and the second PWM control sets the time period for supplying the current to the coil so as to be shorter than the time period for supplying the current to the coil derived from the first relationship.

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