Investigation of characteristics of electro-rheological fluid couplings

Electro-rheological fluids (ERF) are smart materials showing good controllablity in their micro-structure and mechanical strength with an external electric field. In this study, a prototype of a cylindrical ERF coupling was fabricated, and its transmission capability in steady and unsteady running conditions was investigated. The torque transmitted by the coupling with viscous force in wide ranges of driving speed and field strength voltage was measured. Relationship between the transmission torque, the zero field viscosity of ERF and the shear yield stress of ERF under field was obtained, and compared with theoretical prediction. Moreover, by modulating strength of the applied DC field, under certain load and input speed, the output speed conditions of the coupling could be controlled. This provides a new means to construct transmission systems in which output speed could be conveniently adjusted and controlled.