Magnetorheological fluid shock absorber

Patent metadata

Field	Value
Publication number	US-9797465-B2
Application number	US-201414442483-A
Country	US
Kind code	B2
Filing date	Mar 10, 2014
Priority date	Mar 21, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A piston of a magnetorheological fluid shock absorber is provided with a piston core having a small diameter portion mounted on an end portion of the piston rod, an enlarged diameter portion formed continuously in an axial direction with a diameter larger than the small diameter portion and forming a stepped portion, and a large diameter portion formed continuously in the axial direction with a diameter larger than the enlarged diameter portion and having a coil; a ring body surrounding the outer periphery of the piston core and forming a flow passage of the magnetorheological fluid between itself and the large diameter portion; a plate formed annularly and arranged on the outer periphery of the small diameter portion and mounted on one end of the ring body; and a stopper mounted on the small diameter portion and sandwiching the plate between the stopper and the stepped portion.

First claim

The invention claimed is:

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 having a small diameter portion mounted on an end portion of the piston rod, an enlarged diameter portion formed continuously in an axial direction with a diameter larger than the small diameter portion and forming a stepped portion between the enlarged diameter portion and the small diameter portion, and a large diameter portion formed continuously in the axial direction with a diameter larger than the enlarged diameter portion and having a coil provided on an outer periphery, the piston core including:
a first core mounted on an end portion of the piston rod and forming the small diameter portion, the enlarged diameter portion, and a part of the large diameter portion;
a coil assembly having the coil provided on the outer periphery and forming a part of the large diameter portion;
a second core forming a part of the large diameter portion and sandwiching the coil assembly between the second core and the first core;
a fastening member for fastening the second core and the coil assembly to the first core; and
a bypass flow passage formed by penetrating in an axial direction at a position where influence of a magnetic field generated by the coil is smaller than that of the flow passage, the bypass flow passage including:
a first through hole formed in the first core and has a damping characteristic set by the hole diameter thereof; and
a second through hole formed in the second core and formed with a diameter larger than that of the first through hole;

a ring body surrounding the outer periphery of the piston core and forming a flow passage of the magnetorheological fluid between the ring body and the large diameter portion;
a plate formed annularly and arranged on the outer periphery of the small diameter portion and mounted on one end of the ring body; and
a stopper mounted on the small diameter portion and sandwiching the plate between the stopper and the stepped portion.

2. The magnetorheological fluid shock absorber according to claim 1 , wherein
a male screw is formed on the outer periphery of the small diameter portion; and
the stopper has a female screw to be screwed with the male screw formed on the inner periphery thereof and is screwed with the small diameter portion.

Assignees

• Kayaba Industry Co Ltd
• Kyb Corp

Inventors

• Saito Keiji
• Nakamura Kazuhisa
• Teraoka Takashi

Classifications

• F16F9/3214 Primary

  of pistons (F16F9/0227 and F16F9/36 take precedence; throttling passages in or on piston body F16F9/3405) · CPC title

• F16F9/535 Primary

  Magnetorheological [MR] fluid dampers (springs comprising magnetorheological [MR] elastomers F16F1/361) · CPC title

• F16F9/19

  with a single cylinder {and of single-tube type} · CPC title

• F16F2224/045

  magnetorheological · CPC title

• F16F2228/066

  Variable stiffness · CPC title