Patent ID: 9689456
Date: 2017-06-27
CPC Classifications: F16F

Claim:
1. A magnetorheological fluid shock absorber comprising: a cylinder in which a magnetorheological fluid, whose viscosity is changed by an action of a magnetic field, is sealed; a piston slidably arranged in the cylinder and defining a pair of fluid chambers in the cylinder; and a piston rod connected to the piston and extending to an outside of the cylinder, wherein the piston includes: a piston core mounted on an end portion of the piston rod and having a coil provided on an outer periphery; a ring body surrounding the outer periphery of the piston core and forming a flow passage for a magnetorheological fluid between the ring body and the piston core; a plate formed annularly, arranged on the outer periphery of the piston core, and joined by a metal layer through brazing to one end of the ring body; and a stopper sandwiching the plate between the stopper and the piston core, wherein the ring body has a small diameter portion having a diameter smaller than that of another portion of the ring body on the one end, the plate has a flange portion formed annularly by protruding in an axial direction and joined by being fitted in the small diameter portion, a gap is formed between a tip end portion of the flange portion and a base end portion of the small diameter portion, the gap being for pouring a brazing filler metal into a joint portion between the flange portion and the small diameter portion, a portion of the gap, through which the brazing filler metal is poured, has a magnetorheological fluid therein after the pouring, and the portion of the gap extends for an entire distance between the tip end portion of the flange portion and the base end portion of the small diameter portion.