Patent ID: 8127900

Claim:
An electromagnetic shock absorber for a vehicle, comprising: a wheel-side member to be connected to a wheel holder that holds a wheel of the vehicle; a body-side member to be connected to a mount portion that is provided in a body of the vehicle, and movable relative to said wheel-side member upon a movement of said wheel holder and said mount portion toward and away from each other; and a damping force generator having a rotary motor that includes a stationary element and a rotatable element rotatable relative to said stationary element, said stationary element having an electromagnetic coil, said rotatable element having a permanent magnet, said damping force generator being capable of generating, based on a force generated by said rotary motor, a damping force acting against a relative movement of said wheel-side member and said body-side member, wherein said rotary motor has an axis that extends in a both-members-relative-movement direction as a direction of the relative movement of said wheel-side member and said body-side member, wherein said stationary element is supported by said wheel-side member via an elastic body such that said stationary element is movable relative to said wheel-side member in the both-members-relative-movement direction, wherein said rotary motor has a construction allowing a relative movement of said stationary element and said rotatable element in the both-members-relative-movement direction upon a movement of said stationary element relative to said wheel-side member, wherein said stationary element functions as an inertial mass body such that said electromagnetic shock absorber has a function as an unsprung dynamic damper, and wherein a length of said permanent magnet of said rotatable element as measured in the both-members-relative-movement direction is larger than a length of said coil of said stationary element as measured in the both-members-relative-movement direction, by an amount not smaller than a distance by which said stationary element is movable relative to said wheel-side member in the both-members-relative-movement direction.