Hydraulic shock absorber with piston rod position detecting means

Claim 1

A hydraulic shock absorber comprising: a shock absorber body; a piston disposed within said shock absorber body and slidable therein, two fluid-receiving chambers being defined in said shock absorber body on opposite sides of said piston, respectively; a piston rod having one end thereof connected to said piston and the other end thereof projecting from said shock absorber body, said piston rod including an orifice, a hollow portion the interior of which is open to said orifice, and a radial bore open to the interior of said hollow portion and one of said fluid-receiving chambers, said fluid-receiving chambers being in fluid communication via said radial bore, the interior of said hollow portion and said orifice; a rod-shaped member having one end thereof secured to said shock absorber body at an inner portion thereof and extending in an axial direction through said orifice, said rod-shaped member having a cross-sectional area that varies as taken along said axial direction so as to regulate the flow of fluid from said one of said fluid-receiving chambers to the other of said fluid-receiving chambers to a degree corresponding to the relative position of said orifice and said rod-shaped member; and detector means for detecting the relative position of said piston rod and said rod-shaped member, said detector means including a detector body having a tubular shape a magnet integral with said rod-shaped member, and a plurality of magnetically actuatable switches embedded in said detector body and spaced apart at predetermined intervals in the axial direction of the detector body, said detector body disposed in said piston rod in the hollow portion thereof, and said rod-shaped member extending within said detector body.