Delphi Technologies, Inc.

Gm Global Technolgoy Operations, Inc.

Bwi Company Limited S.a.

Other

Beijingwest Industries Co., Ltd.

Robert Thomas Foister

Vardarajan R Iyengar

Sally M Yurgelevic

Thomas W Nehl

Elio Eusebi

William Charles Kruckemeyer

Thomas Allen Baudendistel

Fang Deng

Mark Wayne Long

Sanjiv Gobind Tewani

Alexander Apostolos Alexandridis

James Eugene Dingle

Richard K Gray

Guy Tessier

Frederic Bailly

James C Johnson

Oliver Raynauld

Thomas Wolfgang Nehl

Alexander A Alexandridis

Olivier Reynauld

A magneto-rheological damping assembly including a piston () defining a core (). A pair of spaced electromagnets () are disposed about the core () and are connected to a controller () for selectively generating a magnetic flux. A pair of permanent magnets () are disposed about the electromagnets () and a pole segment () is disposed therebetween. A main gap () extends through the piston () through which magneto-rheological fluid () is conveyed. Flux generated by the magnets controls the viscosity of the fluid in the main gap () to control the damping force of the assembly. The controller () defines an off operating state for cancelling the flux from the permanent magnets () across the main gap (). The core () and the pole segment () define a closed auxiliary gap () extending axially between the electromagnets () and radially between the core () and the internal pole segment () for preventing leakage of flux across the main gap () when the assembly is in the off operating state.

Magneto-rheological damping assembly

A magnetorheolgical (MR) damper includes a piston assembly having a primary channel disposed along a longitudinal axis and contained in a cylinder. MR fluid is also contained in the cylinder. The piston assembly having a primary channel, or primary channel MR piston assembly, includes a piston body having a first end axially spaced from a second end and defining a hole therethrough. The primary channel is defined in an outer body surface of the piston body from the hole at the second end to a coil groove in the outer body surface about the axis. A secondary channel is defined in the outer body surface from the coil groove towards the first end to improve MR damper force performance at low primary channel MR piston assembly velocities.

Magnetorheological (MR) piston assembly with primary and secondary channels to improve MR damper force

A magnetorheological (MR) fluid-based device including an MR piston assembly. The MR piston assembly includes a ferromagnetic MR piston core and an electric coil. The MR piston core has a central longitudinal axis and has an outer circumferential surface substantially coaxially aligned with the central longitudinal axis. The electric coil is positioned in the MR piston core and is substantially coaxially aligned with the central longitudinal axis. A portion, or at least a portion, of the electric coil is buried in the MR piston core under the outer circumferential surface.

Magnetorheological fluid-based device having a magnetorheological piston assembly

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

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 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.

Use of high surface area untreated fumed silica in MR fluid formulation

A hydraulic mount for an automotive vehicle or machine includes opposed mounting members secured to an elastomeric body and a base, respectively. An orifice plate assembly is interposed the body and the base to define a pumping chamber and a reservoir for fluid to flow therebetween through an orifice track of the orifice plate assembly. An electroactive polymer decoupler member is secured in a cavity formed between two orifice plates of the orifice plate assembly. The decoupler member is operably connected to a controller for imposing an electric field on the decoupler member to change its shape and thereby selectively vary the dynamic stiffness of the mount.

Active decoupler hydraulic mount

Magnetorheological fluids containing carbonyl iron particles with surface hydroxyl groups and high specific surface area in combination with nonpolar vehicles such as polyalphaolefins and glycol esters can be formulated to resist particle separation under high separation force applications. When the nonpolar vehicle having a suitably high molecular weight is used, the fluids may be used at working temperatures of the order of 200.degree. C.

Stabilized magnetorheological fluid compositions

A significant increase in the yield stress of a magnetorheological fluid can be obtained at a given volume fraction of solid magnetic particles by employing as the particulate component a mixture of a first component of relatively large particles and a second component of relatively small particles such that the mean diameter of the large particles is at least 5 times the mean diameter of the small particles. The mixture of large and small particles provides a substantial increase in the yield stress without an increase in the viscosity of the mixture in the absence of a magnetic field.

Growing community of inventors

Rochester Hills, MI, United States of America

Robert Thomas Foister