Abstract: Focusing on the problems of magnetorheological (MR) damper for vehicle, in the wear and leakage of oil-seal, the sedimentation of MR fluid and magnetic circuit structure, the improvement measures correspondingly by installing a mono-direction slide valve, a guiding and sealing device, an anti-sedimentation device, and an electromagnetic piston with multi-stage magnetic circuit structure are put forward in a new prototype design. Taking the front damper of Passat B5 car as example, the electromagnetic circuit and hydraulic structure of the MR damper are improved and designed. The prototype experiments are carried out. The damping characteristics of the prototype are analyzed and compared with those of the original passive damper. The results show the feasibility and validity of MR damper with twin tubes and slide valve.

Key words: Damper, Magnetorheological, Semi-active suspension, Vehicle