Abstract: A magnetorheological fluid shock absorber that uses a magnetorheological fluid having a viscosity includes: a tubular cylinder formed from a non-magnetic material and having the magnetorheological fluid sealed into an inner periphery thereof; a piston formed from a non-magnetic material and disposed in the cylinder to be free to slide at an interval, through which the magnetorheological fluid can pass, relative to the inner periphery of the cylinder; a piston rod to which the piston is connected; and a magnet portion attached to the cylinder in order to apply a magnetic field to an interior of the cylinder. The magnet portion includes a permanent magnet having an inner peripheral shape that aligns with an outer periphery of the cylinder; and a ring member formed from a magnetic material and disposed on an outer peripheral side of the permanent magnet.

Abstract: A magnetorheological fluid shock absorber that uses a magnetorheological fluid having a viscosity, includes: a tubular cylinder formed from a non-magnetic material, in which the magnetorheological fluid is sealed; a piston formed from a non-magnetic material and disposed in the cylinder to be free to slide at an interval, through which the magnetorheological fluid can pass, relative to an inner periphery of the cylinder; a piston rod to which the piston is connected; and a magnet portion attached to the cylinder in order to apply a magnetic field to an interior of the cylinder, wherein the magnet portion includes a pair of permanent magnets that are respectively formed in an arc shape having an inner peripheral shape that aligns with an outer periphery of the cylinder, magnetized in a circumferential direction, and disposed so as to face each other about a central axis of the cylinder.