MAGNETORHEOLOGICAL FLUID SHOCK ABSORBER
A magnetorheological fluid shock absorber includes a piston slidably arranged in a cylinder in which magnetorheological fluid whose viscosity changes by the action of a magnetic field is sealed. 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 plate which is annularly formed, arranged on the outer periphery of the piston rod and attached to one end of the flux ring, and a stopper whose axial position is specified with respect to the piston rod and which sandwiches the plate between the piston core and the stopper.
1 . 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 plate which is annularly formed, arranged on the outer periphery of the piston rod and attached to one end of the flux ring; and
a stopper whose axial position is specified with respect to the piston rod and which sandwiches the plate between the piston core and the stopper.
2 . The magnetorheological fluid shock absorber according to claim 1 , further comprising:
a snap ring which fixes the stopper in an axial direction by being fitted to the inner periphery of the stopper.
3 . The magnetorheological fluid shock absorber according to claim 2 , wherein:
an annular groove is formed in correspondence with a position, where the snap ring is provided, on the outer periphery of the piston rod; and
the snap ring is fitted to the annular groove by a radially inwardly contracting force.
4 . The magnetorheological fluid shock absorber according to claim 2 , wherein:
the snap ring is the form of a C-shaped ring, a part of the circumference of which is open;
a tip part of the stopper comes into contact with the plate; and
a tapered portion which is formed into a tapered shape widened toward an end surface and comes into contact with the snap ring is formed at a base end part of the stopper.
5 . The magnetorheological fluid shock absorber according to claim 1 , wherein:
the piston core is fastened to the piston rod; and
the plate is sandwiched by being pressed against the stopper by a fastening force of the piston core.
6 . The magnetorheological fluid shock absorber according to claim 1 , wherein the piston core includes:
a first core which is attached to an end part of the piston rod and comes into contact with the plate;
a coil assembly on the outer periphery of which the coil is provided;
a second core which sandwiches the coil assembly between the first core and the second core; and
a fastening member which fastens the second core and the coil assembly to the first core.