Patent ID: 8616536

Claim:
An active dynamic vibration absorber apparatus for a vehicle that is mounted to a frame of the vehicle and vibrates when power is supplied to attenuate vibration of the vehicle, the active dynamic vibration absorber apparatus comprising: a housing; an upper spring and a lower spring; and a yoke assembly disposed between the upper spring and the lower spring which are plates arranged in parallel, and selectively vibrates up/down in the housing; wherein the yoke assembly has an upper protrusion and a lower protrusion that protrude from a top and a bottom thereof, respectively, the upper protrusion being fastened to a center of the upper spring through the housing, and the lower protrusion being fastened to the center of the lower spring in the housing; wherein the yoke assembly includes: a lower yoke having a cup shape and opening the top thereof and the lower protrusion formed on the bottom of the lower yoke; a magnetic substance fastened to upper surface of the lower yoke; and an upper yoke fastened to the top of the magnetic substance and having the upper protrusion on the top thereof; an insertion space defined between an inner circumference of the lower yoke and outer circumferences of the upper yoke and the magnetic substance; and a coil unit disposed in the insertion space and wound with a coil, wherein an upper portion of the coil unit is fixed to the housing; wherein the lower spring and the upper spring each have two or more spokes radially extending from the center, and ends of the spokes are fastened to the housing; and wherein the spokes are spirally formed.