STUDY ON CHARACTERISTICS OF AN ELECTRORHEOLOGICAL FLUID COUPLING

Abstract

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 was measured. The relationship between the transmission torque, the zero field viscosity of ERF and the shear yield stress of ERF under field was obtained, and was compared with theoretical prediction. Moreover, by modulating the strength of the applied DC field, under a fixed load and input speed, the output speed of the coupling was controlled in the range of transmission ratio from 0 to 1. This provides a means to construct transmission systems in which the output speed can be conveniently adjusted and controlled. Further, square wave electric pulses were applied on the ERF coupling, with a fixed external load added on the output shaft, a uniform stepping rotation of the output shaft has been realized. Experiments showed that under certain conditions the rotation angle of the output axle can be precisely controlled.