“…In recent several years , the research about MRF and its relative devices has made great strides, not only that we have got the high-quality MRF with stable performance and the yield strength can reach to 100kPa [3] , and the related applications also extended to the valve, sealing, instrumentation, sensors, polishing and automobile, machinery and other engineering field [4] . At present, the development of magneto-rheological device research mainly focus on the magnetic fluid active damping shock absorber [5] , magneto-rheological valve [6] , magneto-rheological polishing [7] , engine fan clutch [8] , etc. But the research in the automotive clutch which needs to transmit big torque is less and the application technology is still not mature.…”