Magnetorheological fluid shock absorber

A magnetorheological fluid shock absorber, comprising:

• a cylinder in which magnetorheological fluid whose viscosity changes by the action of a magnetic field is sealed;
• a piston which is slidably arranged in the cylinder and defines a pair of fluid chambers in the cylinder;
• and
• a piston rod which is coupled to the piston and extends to the outside of the cylinder;
• wherein the piston includes:
• a piston core which is attached to an end part of the piston rod and on the outer periphery of which a coil is provided;
• a flux ring which surrounds the outer periphery of the piston core and forms a flow passage for the magnetorheological fluid between the piston core and the flux ring;
• a first plate which is formed into an annular shape and arranged on the outer periphery of the piston rod and specifies the position of one end of the flux ring in an axial direction with respect to the piston core;
• a second plate which is arranged on the inner periphery of the other end of the flux ring and held in contact with the piston core;
• and
• a first snap ring which is fitted to the inner periphery of the flux ring and fixes the second plate in the axial direction.