TORSIONAL VIBRATION DAMPING DEVICE

PURPOSE:To suppress torsional vibration for ensuring highly reliable operation by putting pressure oil suppressing compression to damp vibration in an oil chamber when torsional vibration is generated on a rotary shaft and an active face of a projection on the shaft compresses the oil chamber. CONSTITUTION:When a projection 13 on a rotary shaft 10 is vibrating in the direction to arrow marks A, B, if the same displaces microscopically, for instance, to A direction in high speed, an active face 12A acts so as to compress an oil chamber 15A and draws near a face 14A on a flywheel 14 side quickly. Then, a force to impede the change, that is a squeeze force, is generated, and the squeeze force has a magnitude in proportion to speed of the active face 12A on drawing near the face 14A on the flywheel 14, and it is generated in oil chambers 15A, 15B as a force in arrow mark C for change in displacement direction A, and in arrow mark D for change in displacement direction B. Therefore, squeeze force in put in pressure oil acts so as to suppress the projection 13 in vibration, thereby torsional vibration on the rotary shaft 10 can be effectively damped.