Delphi Technologies, Inc.

Other

Bwi Company Limited S.a.

Vardarajan R Iyengar

Robert Thomas Foister

Sally M Yurgelevic

David Andrew Shal

Patrick Neil Hopkins

John F Hoying

David John Barta

Bruce A Heaston

Michael William Hurtt

Robin Oakley

Timothy John Juuhl

Michael R Lukuc

Perry K Arnold

Mark E Myers

Khaled M Jundi

Darin Duane Dellinger

Jesse D Jones

Thad J Kacsandy

James C Johnson

Justin A Rindler

Charles T West

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

A MR fluid formulation based upon a silicone liquid vehicle thickened with a treated fumed metal oxide and doped with one or more chemicals having hydrogen-bonding capability for use with natural rubber mounts. The MR fluid is resistant to settling of the magnetizable particles upon contact of the fluid with natural rubber. In one exemplary embodiment, the doping chemical is one or a combination of propylene glycol and a bifunctional ethoxylated amine.

Magnetorheological fluid resistant to settling in natural rubber devices

A temperature compensation method for controlling a damping force of a magnetorheological (MR) damper is disclosed. First, a base operating current as a function of a desired force level of a damping force of the MR damper is determined, and a temperature compensation as a function of an operating temperature of the MR damper is determined. Finally, the temperature compensation is applied to the base operating current to generate a compensated operating current as a function of the desired force level of the damping force and the operating temperature of the MR damper. To refine the compensated operating current, the temperature compensation can be determined as both a function of the operating temperature of the MR damper and a relative velocity of the MR damper.

Temperature compensation for magnetorheological fluid dampers

A magnetorheological fluid formulation comprising magnetizable particles dispersed in a non-aqueous, glycol-based liquid vehicle thickened effectively by either a fully treated fumed silica or an organoclay. The surface treated fumed silica is fully treated with a treatment molecule having a molecular weight of at least about 200. The organoclay comprises sepiolite and/or palygorskite. The glycol-based fluid advantageously consists essentially of propylene glycol and optionally ethylene glycol.

Glycol-based MR fluids with thickening agent

A durable magnetorheological fluid for use in a vibration dampening device is described. The MR fluid includes magnetizable particles having a particle size less than about 25 microns, a carrier fluid, a thixotropic agent, and a lubricative additive. The carrier fluid includes a polyalphaolefin and a plasticizer. The lubricative additive has a particle size equal to or less than 10 microns such that the ability of the additive to lubricate the magnetizable particles is optimized. The lubricative additive includes at least one of polytetrafluoroethylene, graphite, and molybdenum disulfide.

Durable magnetorheological fluid

The subject invention provides a magnetorheological (MR) composition having improved resistance to oxidation and increased dispersability in a carrier fluid. The composition includes a plurality of metal particles and a surfactant including a hydrocarbon with at least one of a hydroxyl, a carbonyl, and an amine group bonded to the hydrocarbon for reacting with the metal particles. The surfactant is present in an amount such that from about 1% to about 20% of the amount of the surfactant is adsorbed to the metal particles. The surfactant is reacted with the metal particles such that about 75% to about 100% of a maximum amount of the surfactant adsorbs to the metal particles for improving the resistance of the metal particles to oxidation and for increasing the dispersability of the magnetorheological composition in the carrier fluid. The MR composition according to the subject invention is utilized in a magnetorheological (MR) fluid.

Magnetorheological compositions for use in magnetorheological fluids and method of preparing same

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 exhibiting consistently high yield stress during use. The MR fluid comprises martensitic or ferritic stainless steel particles prepared by a controlled water or inert gas atomization process. The stainless steel particles are resistant to corrosion and oxidation, are generally smooth and spherical, and maintain their shape and size distribution throughout their use under an applied magnetic field.

MR fluids containing magnetic stainless steel

A magnetorheological fluid formulation in which the base liquid is optimized to exhibit an acceptable viscosity, a low volatility, improved low temperature flow properties, and an improved elastomeric compatibility. The fluid formulation includes a base liquid containing a mixture of 1-dodecene polyalphaolefin and a diester, such as dioctyl sebacate. The diester is added to the mixture in an amount effective to produce seal swelling and to lower the pour point. The viscosity of the fluid formulation is suitable for diverse vibration damping applications that require a vibration damping device to operate in the temperature range of about &minus;40&deg; C. to about 100&deg; C. The low volatility and seal swelling properties of the fluid formulation reduce, inhibit or eliminate fluid loss about the seals of the vibration damping device.

Optimized synthetic base liquid for magnetorheological fluid formulations

A durable magnetorheological fluid suitable for use in high compression vibration dampening devices comprising mechanically hard magnetizable particles of unreduced carbonyl iron, cobalt-iron alloys, or mixtures thereof, a carrier fluid of a mixture of polyalphaolefin and a plasticizer, unreduced fumed silica and optionally an ethoxylated amine.

Durable magnetorheological fluid compositions

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.

Stabilization of magnetorheological fluid suspensions using a mixture of organoclays

A durable MR fluid formulation is described which includes mechanically hard magnetizable particles, a carrier fluid derived from a polyalphaolefin and a plasticizer, and at least one colloidal additive such as colloidal polytetrafluoroethylene or colloidal graphite. The use of these colloidal additives inhibits surface-to-surface contact and scuffing while providing reliable lubrication under boundary lubrication conditions.

A method of testing magnetorheological fluid comprises cycling the fluid at an elevated temperature, allowing the fluid to stand, performance testing the fluid, cycling the fluid at superimposed frequencies, and noting settling characteristics of the fluid.

Settling test for magnetorheological fluids

A magnetorheological fluid formulation exhibiting high yield stress at high surfactant concentrations. The formulation has a strong network formation due to incorporation of a high surface area untreated fumed silica as a thixotropic agent. This untreated fumed silica has a surface area of at least about 250 m /g, which enables a surfactant concentration in the formulation in an amount up to about 35% by weight relative to the weight of the fumed silica.

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Macomb, MI, United States of America

Vardarajan R Iyengar