To provide a vibration attenuation device that prevents abnormal noise or microvibration in a region where a rotation speed of a rotator is slow, and has excellent vibration attenuation performance in a rotation speed region other than the slow rotation speed.
The vibration attenuation device attached to the rotator so as to attenuate a torsional vibration generated by the rotator includes: a rolling chamber 24 that integrally rotates with the rotator; a rolling body 25 that is rollably housed in the rolling chamber 24; a movable member 23 that, when a centrifugal force generated on the rolling body 25 is small, moves so that the rolling body 25 is pressed on any part of an inner wall surface 21B in the rolling chamber 24, and that, when the centrifugal force is large, moves in a direction away from the rolling body 25; and a recessed part that is formed on a surface 23A facing the rolling body 25 in the movable member 23, or any part of the inner wall surface 21B where the rolling body 25 is pressed by the movable member 23, and that retreats in an axial line direction of the rotator with respect to the rolling body 25 to restrict the rolling body 25 in its rolling direction.
AMANO HIROYUKI
AIJIMA SHINGO