Lubricant compositions comprising (a) an oil of lubricating viscosity and (b) a phosphonate ester other than a zinc salt. The phosphonate ester may be the reaction product of (i) phosphonic acid or a monomeric ester thereof with (ii) a propanediol having hydroxy groups in both the 1 and 3 positions and one or more of the carbon atoms of the propyl units are substituted with one or more alkyl groups such that the total number of carbon atoms in the propanediol ranges from 4 to 12. The molar ratio of (i) to (ii) may be 0.9:1.1 to 1.1 to 0.9.

The disclosed technology relates to a lubricant composition for automotive or industrial gears, as well as axles and bearings, the lubricant composition containing an oil of lubricating viscosity and a metal alkylthiophosphate compound, such as zinc dialkyldithiophosphate, as well as a method of obtaining extreme pressure performance in automotive or industrial gears, axles and bearings at lower sulfur content than is typical, by lubricating such automotive or industrial gears, axles and bearings with a lubricant composition containing a metal alkylthiophosphate compound, such as zinc dialkyldithiophosphate.

The invention provides a compressor oil, wherein 2,6-di-tert-butylphenol and tris (2,4-di-tert-butylphenyl) phosphite are added to a base oil having a naphthene content of from 17 to 30% based on the total amount of the base oil, and has a pour point of −25° C. or lower. 2,6-di-tert-butylphenol is effective when it is contained in an amount of from 0.5 mass % to 6.0 mass % based on the total amount of the compressor oil, and tris (2,4-di-tert-butylphenyl) phosphite is effective when it is contained in an amount of from 0.3 mass % to 2.0 mass % based on the total amount of the compressor oil. Furthermore, adding an alkaline earth metal salt of alkylsalicylic acid in combination is even more effective. The amount thereof used is preferably from 0.05 mass % to 2.0 mass %.

The invention provides a compressor oil, wherein 2,6-di-tert-butylphenol and tris (2,4-di-tert-butylphenyl) phosphite are added to a base oil having a naphthene content of from 17 to 30% based on the total amount of the base oil, and has a pour point of −25° C. or lower. 2,6-di-tert-butylphenol is effective when it is contained in an amount of from 0.5 mass % to 6.0 mass % based on the total amount of the compressor oil, and tris (2,4-di-tert-butylphenyl) phosphite is effective when it is contained in an amount of from 0.3 mass % to 2.0 mass % based on the total amount of the compressor oil. Furthermore, adding an alkaline earth metal salt of alkylsalicylic acid in combination is even more effective. The amount thereof used is preferably from 0.05 mass % to 2.0 mass %.

A lubricating oil composition including: a lubricant base oil; (A) a triazole metal deactivator in an amount of 0.005 to 0.03 mass % in terms of nitrogen on the basis of the total mass of the composition; and (B1) a succinimide compound represented by the following general formula (1) in an amount of 0.0005 to 0.02 mass % in terms of nitrogen on the basis of the total mass of the composition:

##STR00001##

wherein in the general formula (1), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a C1-36 linear or branched chain alkyl or alkenyl group, and at least one of R.sup.1 and R.sup.2 is a C8-36 linear or branched chain alkyl or alkenyl group, and n represents an integer of 1 to 10.

A lubricating oil composition including: a lubricant base oil; (A) a triazole metal deactivator in an amount of 0.005 to 0.03 mass % in terms of nitrogen on the basis of the total mass of the composition; and (B1) a succinimide compound represented by the following general formula (1) in an amount of 0.0005 to 0.02 mass % in terms of nitrogen on the basis of the total mass of the composition:

##STR00001##

wherein in the general formula (1), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a C1-36 linear or branched chain alkyl or alkenyl group, and at least one of R.sup.1 and R.sup.2 is a C8-36 linear or branched chain alkyl or alkenyl group, and n represents an integer of 1 to 10.

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.

A lubricating oil composition including: a lubricating base oil; (A) a poly(meth)acrylate having a weight average molecular weight of no more than 50,000, in an amount of 2 to 10 mass %; (B) a phosphite ester of the general formula (1) in an amount of 0.01 to 0.06 mass % in terms of P; (C) a thiadiazole compound in an amount of 0.01 to 0.2 mass %; and (D) a Ca salicylate detergent in an amount of 0.005 to 0.03 mass % in terms of Ca, wherein the lubricating oil composition has a kinematic viscosity at 40° C. of 4.0 to 20.0 mm.sup.2/s, and a kinematic viscosity at 100° C. of 1.8 to 5.2 mm.sup.2/s; and has a ratio [S]/[P] of 2.2 to 4.0, wherein the [S] represents a sulfur content, and the [P] represents a phosphorus content: ##STR00001##
wherein R.sup.1 and R.sup.2 are each independently a group having 5 to 20 carbons represented by the general formula (2); and ##STR00002##
wherein R.sup.3 is a C2-17 linear chain hydrocarbon group, and R.sup.4 is a C2-17 linear chain hydrocarbon group.

A lubricating oil composition including: a lubricating base oil; (A) a poly(meth)acrylate having a weight average molecular weight of no more than 50,000, in an amount of 2 to 10 mass %; (B) a phosphite ester of the general formula (1) in an amount of 0.01 to 0.06 mass % in terms of P; (C) a thiadiazole compound in an amount of 0.01 to 0.2 mass %; and (D) a Ca salicylate detergent in an amount of 0.005 to 0.03 mass % in terms of Ca, wherein the lubricating oil composition has a kinematic viscosity at 40° C. of 4.0 to 20.0 mm.sup.2/s, and a kinematic viscosity at 100° C. of 1.8 to 5.2 mm.sup.2/s; and has a ratio [S]/[P] of 2.2 to 4.0, wherein the [S] represents a sulfur content, and the [P] represents a phosphorus content: ##STR00001##
wherein R.sup.1 and R.sup.2 are each independently a group having 5 to 20 carbons represented by the general formula (2); and ##STR00002##
wherein R.sup.3 is a C2-17 linear chain hydrocarbon group, and R.sup.4 is a C2-17 linear chain hydrocarbon group.