The electrorheological effects and its application to torque transmission

The authors present the results of a series of tests aimed at the assessment of ER (electrorheological) fluids in a continuously variable torque transmission device under both DC and AC excitation. Some of the problems which need further study are outlined. In particular, tests conducted on the torque transmission device indicate that the performance is limited by the shear strength of the particular ER fluid used. This shear strength, used here under dynamic conditions, is of course less than that which would be obtained under the more usual (fluid test) static conditions when the strain rate is extremely small. One of the problems being addressed by the authors is concerned not only with the maximum torque capability (since there are numerous industrial applications when 8 nm would be acceptable) but more with the minimum torque transmitted through such a device when the applied field is zero