Delphi Technologies, Inc.

Other

Bwi Company Limited S.a.

Sally M Yurgelevic

Robert Thomas Foister

Vardarajan R Iyengar

A magnetorheological fluid formulation comprising magnetizable particles dispersed in carrier fluid and a thixotropic agent wherein the thixotropic agent comprises a fluorocarbon grease.

Magnetorheological fluid with a fluorocarbon thickener

An additives package for use in an MR fluid formulation is provided, as well as an MR fluid formulation containing the additives package. In one embodiment, the additives package comprises an organomolybdenum dithiocarbamate, an ashless dithiocarbamate, and a triazole compound, such as a tolutriazole compound. In another embodiment, the additives package may further include an aminic antioxidant, such as an alkylated diphenylamine. In another embodiment, the additives package is free of an organomolybdate ester. In another embodiment, the additives package consists of the organomolybdenum dithiocarbamate, the ashless dithiocarbamate, the triazole compound, and optionally the aminic antioxidant. In addition to the additives package, the magnetorheological fluid formulation comprises magnetizable particles, a carrier fluid, and a thickening agent.

Additives package and magnetorheological fluid formulations for extended durability

An MR fluid formulation comprising water-atomized iron powder dispersed in a liquid vehicle, wherein the atomized iron powder contributes to a higher magnetic effect, a lower viscosity and suitability for high temperature applications. The magnetizable particles are prepared by controlled water atomization and comprise iron having a passivating oxide surface layer. The passivating oxide surface layer advantageously comprises iron oxide and at least one alloying metal oxide, such as manganese oxide. Advantageously, the particles have a grain size of at least 4 &mgr;m and a mean diameter in the range of about 8-25 &mgr;m. The liquid vehicle advantageously comprises a mixture of at least two liquid components of different surface functionality and an organoclay stabilization mixture in which at least one organoclay is selected for each liquid vehicle component. Exemplary MR fluid formulations of the present invention utilize a high-viscosity, low volatility base fluid, water-atomized iron powder, multi-component organoclays and multi-component additives to achieve the desired viscosity and durability of a fully formulated MR fluid which will satisfy the requirements of second and third generation MR fluids.

Low-cost MR fluids with powdered iron

A magnetorheological fluid formulation comprising magnetizable particles dispersed in a multi-component liquid vehicle comprising an organoclay stabilization mixture. At least one organoclay is selected for each liquid vehicle component, each organoclay having a surface chemistry that renders it preferentially compatible with the surface functionality of one of the liquid components relative to its compatibility to the remaining components whereby it is effective to stabilize, or gel, that component. A method of making an MR fluid is also provided in which liquid vehicle components are blended together, the organoclay mixture is added to the blend, and magnetizable particles are suspended therein, resulting in a stable MR fluid of suitable viscosity and yield stress.

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Eastpointe, MI, United States of America

Sally M Yurgelevic