Provided is a grease composition for a ball joint that can reduce the wear of a ball seat at a slide region and also has excellent compatibility with a dust cover. The grease composition for a ball joint comprises a base oil, a thickener, and an additive. The base oil contains an ethylene--olefin copolymer and the kinetic viscosity of the base oil at 40 C. is 2,000 to 6,000 mm.sup.2 /s. The additive contains a polar wax (e.g., monoamide wax or ester wax).

Provided is a grease composition for a ball joint that can reduce the wear of a ball seat at a slide region and also has excellent compatibility with a dust cover. The grease composition for a ball joint comprises a base oil, a thickener, and an additive. The base oil contains an ethylene--olefin copolymer and the kinetic viscosity of the base oil at 40 C. is 2,000 to 6,000 mm.sup.2 /s. The additive contains a polar wax (e.g., monoamide wax or ester wax).

The present invention relates to a lubricating oil composition and a continuously-variable transmission filled with the lubricating oil composition. The present invention also relates to a friction control method for a continuously-variable transmission, the method using the lubricating oil composition. This lubricating oil composition is characterized by containing: (A) a base oil; (B) a diamine; (C) a glycolic acid amide; and (D) a phosphorous ester. With this lubricating oil composition, it is possible to provide different wear characteristics between different parts, so in a preferable embodiment of the present invention, the lubricating oil composition is suitably used as a lubricating oil for variable transmissions, in particular, metal-belt continuously-variable transmissions.

The present invention relates to a lubricating oil composition and a continuously-variable transmission filled with the lubricating oil composition. The present invention also relates to a friction control method for a continuously-variable transmission, the method using the lubricating oil composition. This lubricating oil composition is characterized by containing: (A) a base oil; (B) a diamine; (C) a glycolic acid amide; and (D) a phosphorous ester. With this lubricating oil composition, it is possible to provide different wear characteristics between different parts, so in a preferable embodiment of the present invention, the lubricating oil composition is suitably used as a lubricating oil for variable transmissions, in particular, metal-belt continuously-variable transmissions.

The lubricating oil composition for a refrigerator of the present invention is used with a refrigerant containing carbon dioxide, and contains a base oil (A) containing a polyoxyalkylene glycol as a major component, and an alcohol (B) having at least one hydroxy group, in which a total number of the hydroxy group and an ether bond is from 2 to 3 (provided that the number of an ether bond may be 0).

The lubricating oil composition for a refrigerator of the present invention is used with a refrigerant containing carbon dioxide, and contains a base oil (A) containing a polyoxyalkylene glycol as a major component, and an alcohol (B) having at least one hydroxy group, in which a total number of the hydroxy group and an ether bond is from 2 to 3 (provided that the number of an ether bond may be 0).

A lubricating oil for hybrid engine includes a major amount of an oil of lubricating viscosity; a boron-containing compound in an amount to provide 50 to 300 ppm of boron to lubricating oil composition; an overbased calcium salicylate or a mixture of an overbased calcium sulfonate and overbased calcium salicylate individually having a total base number of greater than 150 mg KOH/g, measured by the method of ASTM D-2896, present in an amount that provides 800 ppm to 1800 ppm of calcium to the lubricating oil composition; zinc dithiophosphate (ZnDTP) in an amount to bring from 100 to 800 ppm of phosphorus to the lubricating oil composition; and a non-dispersant comb polymethacrylate (PMA) viscosity index improver (VII). The boron-containing compound includes a borated dispersant. The KV at 100 C. of the lubricating oil composition is from 6 cSt to 8.5 cSt, the KV at 40 C. of the lubricating oil composition is from 25 cSt to 35 cSt, and the VI of the lubricating oil composition is greater than 200.

A lubricating oil for hybrid engine includes a major amount of an oil of lubricating viscosity; a boron-containing compound in an amount to provide 50 to 300 ppm of boron to lubricating oil composition; an overbased calcium salicylate or a mixture of an overbased calcium sulfonate and overbased calcium salicylate individually having a total base number of greater than 150 mg KOH/g, measured by the method of ASTM D-2896, present in an amount that provides 800 ppm to 1800 ppm of calcium to the lubricating oil composition; zinc dithiophosphate (ZnDTP) in an amount to bring from 100 to 800 ppm of phosphorus to the lubricating oil composition; and a non-dispersant comb polymethacrylate (PMA) viscosity index improver (VII). The boron-containing compound includes a borated dispersant. The KV at 100 C. of the lubricating oil composition is from 6 cSt to 8.5 cSt, the KV at 40 C. of the lubricating oil composition is from 25 cSt to 35 cSt, and the VI of the lubricating oil composition is greater than 200.

A metal-containing detergent, suitable for use as a lubricant additive, in the form of a concentrate in oil in which a basic metal-containing material is maintained in dispersion or solution in the oil by a gemini surfactant system comprising, or being derivable or derived from, a double bond-unsaturated carboxylic acid having 8 to 30 carbon atoms, the double bond or bonds of which being functionalized to carry polar groups across or on the double bond or bonds and the carboxylic acid group or groups thereof being functionalized to become an amide or ester group carrying at least one alkyl group having 4 to 20 carbon atoms.

A metal-containing detergent, suitable for use as a lubricant additive, in the form of a concentrate in oil in which a basic metal-containing material is maintained in dispersion or solution in the oil by a gemini surfactant system comprising, or being derivable or derived from, a double bond-unsaturated carboxylic acid having 8 to 30 carbon atoms, the double bond or bonds of which being functionalized to carry polar groups across or on the double bond or bonds and the carboxylic acid group or groups thereof being functionalized to become an amide or ester group carrying at least one alkyl group having 4 to 20 carbon atoms.