Shock absorber having bidirectional valve and flow restricting passage parallel to the valve

摘要

Shock absorber including a cylinder body and a piston cooperating to two chambers one and the other of which respectively function as high-pressure and low-pressure chambers, a piston rod fixed to the piston, and a damping force control device including (i) a hard valve which permits a flow of a working fluid from the high-pressure chamber toward the low-pressure chamber when a difference between fluid pressures in the high-pressure and low-pressure chambers is larger than a predetermined threshold, (ii) a soft valve which permits the fluid flow from the high-pressure chamber toward the low-pressure chamber when the pressure difference is not larger than the threshold, and (iii) a flow restricting fluid passage disposed in parallel with at least one of the hard and soft valves, and wherein at least one of the hard and soft valves and the soft valve permits a flow of the fluid therethrough during both elongation and contraction of the shock absorber.