Abstract: An electrorheological damping device for reducing translational vibration between two bodies comprises a rotary electrorheological damper and transmission means for converting the translational vibration between the two bodies to the rotary motion of the rotary electrorheological damper. The rotary electrorheological damper includes a stator and a rotor that are coaxially arranged. The stator have a plurality of stator electrodes, and the rotor have a plurality of rotor electrodes. The stator electrodes and the rotor electrodes face each other alternatively within at least one fluid chamber. The fluid chamber is filled with an electrorheological fluid that varies its rheological properties when exposed to an electric field. The electrorheological fluid fills spaces between each pair of the stator and rotor electrodes.

Abstract: An electrorheological fluid that includes a dispersed particulate phase of anhydrous amorphous ceramic particles. The anhydrous amorphous ceramic particles can be of a very precisely tailored composition that is unavailable in crystalline form, for obtaining enhanced electrorheological response. The amorphous particles are substantially free of water when used, and have reduced tendency to absorb water in use. Accordingly, the electrorheological fluid containing anhydrous amorphous electrorheologically responsive ceramic particles has wide applicability for use, and enhanced durability in such use.

Abstract: An improved method of inducing a change in the dynamic torque transmission of an electrorheological fluid in response to an electric field at low current comprising the steps of: (a) selecting a nonconductive liquid phase (e.g. high dielectric hydrocarbon oil); (b) dispersing in the nonconductive liquid phase a particulate phase substantially free of adsorbed water (e.g. zeolite); and (c) subjecting the resulting electrorheological fluid to an electric potential in excess of about one kilovolt at a current density of less than about one-third microamp per square inch. Such a method achieves a rate of increase of dynamic transmission of torque per unit voltage, dM/dV, in excess of about 0.034 ft-lbs.times.10.sup.-3 /kV and a ratio of dynamic transmission of torque at an electric field strength of at least 2.4 kV to the dynamic transmission of torque at zero field strength, M/Mo, of at least about 2.

Abstract: An improved electric field dependent fluid and method of preparing the same for use at temperatures in excess of 100.degree. C. (typically 120.degree. C.) without releasing water comprising: a nonconductive liquid phase; and a dispersed particulate crystalline zeolite phase (e.g., M.sub.(x/n) [AlO.sub.2).sub.x (SiO.sub.2).sub.y ] wH.sub.2 O where M is a metal cation or mixture of metal cations of average valence charge n, x and y are integers and the ratio of y to x is from about 1 to about 5, and w is a variable). Such field dependent fluids are particularly useful in automotive and/or other high temperatures applications.