Electro-rheological fluid having high dielectric breakdown stength and methods of making and storing the electro-rheological fluid

摘要

An electro-rheological fluid made from an oil medium and fine particulates by mixing, is highly reliable and in which dielectric breakdown, such as generation of electrical discharge, is very low even when a high voltage is applied. A method of manufacturing the electro-rheological fluid and a method of storing the fluid are also provided. The electro-rheolological fluid includes fine particulates dispersed in an oil medium having an electric insulation property, and has a dielectric breakdown strength of 4 kV/mm or more. When the electro-rheological fluid is placed under a reduced pressure of 10 Pa, foaming does not occur. Alternatively, the electro-reheoleological fluid can contain 20% by volume or more of a gas contained in the oil medium that has a dielectric breakdown strength of 4 kV/mm or more.