An electrorheological fluid which comprises a dispersion medium containing fluorine atoms in an amount larger than 0 wt % but not larger than 50.0 wt % and particles for electrorheological fluid use that are contained in the dispersion medium in an amount of 10-50 vol % of the total volume of the dispersion medium and the particles, the particles comprising a sulfonic-acid-group-containing polymer having a sulfonic acid group content of 30-70 wt %.

A system may include an output manifold that may be in fluid communication with a reservoir and that may include multiple discharge ports. Each of the discharge ports may be configured to discharge electrorheological fluid into a housing. A recovery manifold may be in fluid communication with the reservoir and include multiple recovery ports. Each of the recovery ports may be configured to receive the electrorheological fluid from a housing. A gas remover may be positioned to extract gas from the electrorheological fluid received from the recovery ports. A housing may be connected to the system, and electrorheological fluid from the system may be pumped through the housing and the gas remover.

The present disclosure relates to methods of lubricating an electric or a hybrid-electric transmission using a lubricant including a solvent system with a blend of one or more base oils with a branched diester and one or more poly(meth)acrylate copolymers, transmissions therefor, and lubricating compositions suitable for such applications that exhibit good lubricant properties, good electrical properties, and good cooling efficiency at the same time.

Provided is a lubricating oil composition for a transmission having excellent gear properties, clutch properties, cooling properties, and electric insulating properties. The lubricating oil composition for a transmission preparing by blending (A) a base oil, (B) a viscosity index improver having a mass average molecular weight of 10,000 to 50,000, and (C-1) a polyamide and/or (C-2) a polyol ester, the base oil (A) including (A-1) a synthetic oil having a kinematic viscosity at 100 C. of 1.0 to 10.0 mm.sup.2/s.

This vibration damping device (10) includes a magnetorheological fluid composition in a cylinder (12). The magnetorheological fluid composition includes magnetic particles; a dispersant having the magnetic particles dispersed therein; and a friction modifier. The friction modifier is an amine-based additive having a hydrocarbon chain having 14 to 22 carbon atoms, preferably an alkyl chain or an alkenyl chain. The content of the friction modifier is 0.1 to 5 mass %.

The present invention provides an electrorheological fluid, which includes a dielectric particle, a conductor particle and insulating oil, and the dielectric particle is evenly dispersed in the insulating oil; wherein the conductor particle is evenly dispersed in the insulating oil or inlaid in an interior and on a surface of the dielectric particle. The electrorheological fluid has the advantages of high shear stress, long service life, good temperature stability and small leakage current.

An electrorheological fluid which comprises a dispersion medium containing fluorine atoms in an amount larger than 0 wt % but not larger than 50.0 wt % and particles for electrorheological fluid use that are contained in the dispersion medium in an amount of 10-50 vol % of the total volume of the dispersion medium and the particles, the particles comprising a sulfonic-acid-group-containing polymer having a sulfonic acid group content of 30-70 wt %.

A bearing device with first and second bearing surfaces facing each other and which are moveable relative to one another. The first and second bearing surfaces are separated by a bearing gap filled with a lubricant. The lubricant comprises a carrier fluid and particles which respond to magnetic or electric fields. The particles are suspended in the carrier fluid in the absence of magnetic or electric fields. One or more magnetic or electric field generators are embedded in the first or second bearing surface to generate a localized magnetic or electric field which locally removes the particles from suspension by exerting a field force on the particles. This forms a local flow obstruction on at least one of the bearing surfaces in the form of an agglomerate of previously suspended particles. The local flow obstruction locally obstructs a flow of the lubricant.

The invention provides a lubricating oil for fluid dynamic bearing including as a base oil a monoester oil free of unsaturated bond, and having an absolute viscosity of 2.0 to 3.0 mPa.Math.s at 100 C. a viscosity index of 130 or more and a pour point of 20 C. or less.

A system may include an output manifold that may be in fluid communication with a reservoir and that may include multiple discharge ports. Each of the discharge ports may be configured to discharge electrorheological fluid into a housing. A recovery manifold may be in fluid communication with the reservoir and include multiple recovery ports. Each of the recovery ports may be configured to receive the electrorheological fluid from a housing. A gas remover may be positioned to extract gas from the electrorheological fluid received from the recovery ports. A housing may be connected to the system, and electrorheological fluid from the system may be pumped through the housing and the gas remover.