A lubricant composition of an oil of lubricating viscosity and a phosphite ester reaction product of a monomeric phosphorous acid or an ester thereof with a first alkylene diol having two hydroxy groups in a 1,4 or 1,5 or 1,6 relationship and a second, alkyl-substituted, diol being a substituted 1,3-propylene diol, exhibits good wear and frictional performance.

A drive device includes a plurality of gears; and a grease composition that is held on a tooth flank of at least one gear of the gears. The at least one gear is made of a resin. The grease composition contains a hydrocarbon base oil, lithium soap serving as a thickener, and olefin resin powder. A weight ratio between the hydrocarbon base oil and the lithium soap in the grease composition is in a range of 94.5:5.5 to 96.0:4.0. A consistency of the grease composition is in a range of 360 to 400.

A drive device includes a plurality of gears; and a grease composition that is held on a tooth flank of at least one gear of the gears. The at least one gear is made of a resin. The grease composition contains a hydrocarbon base oil, lithium soap serving as a thickener, and olefin resin powder. A weight ratio between the hydrocarbon base oil and the lithium soap in the grease composition is in a range of 94.5:5.5 to 96.0:4.0. A consistency of the grease composition is in a range of 360 to 400.

A drive device includes a plurality of gears; and a grease composition that is held on a tooth flank of at least one gear of the gears. The at least one gear is made of a resin. The grease composition contains a hydrocarbon base oil, lithium soap serving as a thickener, and olefin resin powder. A weight ratio between the hydrocarbon base oil and the lithium soap in the grease composition is in a range of 94.5:5.5 to 96.0:4.0. A consistency of the grease composition is in a range of 360 to 400.

A drive device includes a plurality of gears; and a grease composition that is held on a tooth flank of at least one gear of the gears. The at least one gear is made of a resin. The grease composition contains a hydrocarbon base oil, lithium soap serving as a thickener, and olefin resin powder. A weight ratio between the hydrocarbon base oil and the lithium soap in the grease composition is in a range of 94.5:5.5 to 96.0:4.0. A consistency of the grease composition is in a range of 360 to 400.

A drive device includes a gear having a hole; a shaft that passes through the hole; and a grease composition that is held in a clearance between the shaft and an inner peripheral surface of the hole. The gear rotates on a peripheral surface of the shaft. At least one of the gear and the shaft is made of a resin. The clearance is in a range of 10 to 110 m. The grease composition contains a hydrocarbon base oil and lithium soap serving as a thickener. A weight ratio of the hydrocarbon base oil to the lithium soap is in a range of 94.5:5.5 to 96.0:4.0. A consistency of the grease composition is in a range of 360 to 400.

A drive device includes a gear having a hole; a shaft that passes through the hole; and a grease composition that is held in a clearance between the shaft and an inner peripheral surface of the hole. The gear rotates on a peripheral surface of the shaft. At least one of the gear and the shaft is made of a resin. The clearance is in a range of 10 to 110 m. The grease composition contains a hydrocarbon base oil and lithium soap serving as a thickener. A weight ratio of the hydrocarbon base oil to the lithium soap is in a range of 94.5:5.5 to 96.0:4.0. A consistency of the grease composition is in a range of 360 to 400.

The disclosure includes a grease composition comprising providing at least one polyol-ester base oil, at least one fatty-acid metal soap, at least one dimercaptothiadiazole derivative, and at least one sulfurous fatty-acid ester, the amount of active sulfur provided by the sulfurous fatty-acid ester at 150 C. according to the ASTM D1662 standard being greater than or equal to 0.18 wt % with respect to the total weight of the grease composition.

The invention provides a lubricating grease composition comprising an oil of lubricating viscosity, a metallic soap thickener and a boron-containing compound, wherein the boron containing compound comprises a borate ester comprising at least one alkyl group having a branch at the position or higher. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

The invention provides a lubricating grease composition comprising an oil of lubricating viscosity, a metallic soap thickener and a boron-containing compound, wherein the boron containing compound comprises a borate ester comprising at least one alkyl group having a branch at the position or higher. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.