Shock absorber using electro-viscous fluid

Claim 1

A shock absorber comprising: a main body including a cylindrical portion having opposite open ends, and closure wall portions fluid-tightly closing the open ends of the cylindrical portion; an inner cylindrical member disposed within said main body, with a predetermined radial spacing from an inner circumferential surface of said cylindrical portion, and cooperating with said main body to define an inner cylinder chamber and an outer annular space; a psiton slidably received within said inner cylinder chamber, so as to divide the cylinder chamber into two fluid chambers; means for defining a communication passage for fluid communication between said two fluid chambers, said means including a portion formed within said annular space; an electro-viscous fluid filling said two chambers and said communication passage; an operating rod secured to said piston and slidably and fluid-tightly extending through one of said two closure wall portions of said main body; a balancing rod secured to said piston and slidably and fluid-tightly extending through the other of said two closure wall portions, said operating and balancing rods having a same cross sectional area; and at least one pair of electrodes one of which consists of at least a portion of said cylindrical portion of said main body and the other of which consists of at least a portion of said inner cylindrical portion, the electrodes of each of said at least one pair being disposed opposite to each other, so as to define at least a portion of said communication passage, for applying a voltage to a mass of said electro-viscous fluid in said portion of said communication passage and wherein said means for defining at least one communication passage comprises an electrically insulating strip wound on an outer circumferential surface of said inner cylindrical member such that turns of said strip are spaced apart from each other in an axial direction of said inner cylindrical member, said turns of said strip cooperating with said outer circumferential surface of said inner cylindrical member to define a groove which is closed by said inner circumferential surface of said cylindrical portion of said main body, whereby a portion of a single communication passage as said communication passage is formed within said annular space.