Disclosed is a lubricating oil composition capable of having a good balance of electrical insulation, seizure resistance and wear resistance. In particular, the lubricating oil composition comprises: (A) a lubricant base oil; (B) an alkaline earth metal detergent; (C) a triazole-based compound represented by the following general formula (1) or (2): ##STR00001##
wherein R.sup.1-R.sup.6 are as defined herein; (D) at least one sulfur-containing compound selected from the group consisting of a sulfur-containing heterocyclic ether compound and a sulfide compound; and (E) an ashless dispersant.

There is provided a fluorine-containing ether compound represented by the following formula. R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—OCH.sub.2CH(OH)CH.sub.2O—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5 (in the formula, R.sup.3 represents a perfluoropolyether chain; R.sup.2 and R.sup.4 represent a divalent linking group having a polar group and may be the same or different from each other; R.sup.1 and R.sup.5 represent a terminal group bonded to an oxygen atom of R.sup.2 or R.sup.4 and may be the same or different from each other; and at least one of R.sup.1 and R.sup.5 is an organic group having 1 to 8 carbon atoms and at least one of hydrogens included in the organic group is substituted by a cyano group).

A fluorine-containing ether compound represented by a formula (1) shown below.

R.sup.1—(O(CH.sub.2).sub.a).sub.b-[A]-[B]—O—CH.sub.2—R.sup.2—CH.sub.2—R.sup.3  (1)

(In the formula (1), R.sup.1 is an alkyl group which may have a substituent, or an organic group having at least one double bond or triple bond. Further, a represents an integer of 2 to 4, and b is 0 or 1. [A] is represented by a formula (2): —(OCH.sub.2CH(OH)CH.sub.2).sub.c— (wherein c is 1 or 2). [B] is represented by a formula (3): —(O(CH.sub.2).sub.eCH(OH)CH.sub.2).sub.d— (wherein d is 0 or 1, and e represents an integer of 2 to 4). However, the sum of c in the formula (2) and d in the formula (3) is 2. R.sup.2 is a perfluoropolyether chain. R.sup.3 is represented by a formula (4): —(OCH.sub.2CH(OH)CH.sub.2).sub.2—O—CH.sub.2(CH.sub.2).sub.fOH (wherein f represents an integer of 2 to 5).

Provided herein are hydrocarbon compositions suitable for use as a lubricant comprising sulfur between about 30 ppm to about 220 ppm, and aromatics between about 0.2 wt. % to about 3 wt. %. The present hydrocarbon compositions comprise a blend of one or more base stocks and a high-sulfur containing material and can demonstrate an improved oxidation performance as a lubricant in weighted piston deposit merits and/or by viscosity increase.

Lubricating oil compositions may include a base oil, a succinimide compound, and a thioheterocyclic compound. Such compositions may have a sulfur content of 0.10 mass % to 1.00 mass % based on a total amount of the composition. A phosphorus content represented by P in mass % and a sulfated ash content represented by M in mass %, based on the total amount of such compositions, may satisfy any of conditions A to C: condition A: P<0.03, and M<0.3; condition B: P<0.03 and 0.3≦M≦0.6; and condition C: 0.03≦P≦0.06 and M<0.3.

Disclosed is a lubricating oil composition capable of having a good balance of electrical insulation, seizure resistance and wear resistance. In particular, the lubricating oil composition comprises: (A) a lubricant base oil; (B) an alkaline earth metal detergent; (C) a triazole-based compound represented by the following general formula (1) or (2):

##STR00001##

wherein R.sup.1-R.sup.6 are as defined herein; (D) at least one sulfur-containing compound selected from the group consisting of a sulfur-containing heterocyclic ether compound and a sulfide compound; and (E) an ashless dispersant.

A lubricating oil composition may include a base oil (A), a zinc dithiophosphate (B) comprising a compound (B1) of formula (b-1), calcium sulfonate (C), and a seal sweller (D). In formula (b-1), R.sup.1 to R.sup.4 are each independently an alkyl group. However, at least one of R.sup.1 to R.sup.4 is a prescribed straight-chain alkyl group, and at least one of R.sup.1 to R.sup.4 is a prescribed branched chain alkyl group.

An additive for a lubricating composition includes an ionic tetrahedral borate compound which includes a cation and a tetrahedral borate anion having a boron atom, the boron atom has at least one aliphatic bidentate di-oxo ligand. The cation may be selected to provide detergent and/or dispersant and/or antioxidant properties to a lubricating composition.

The present invention provides a grease composition for electrical contacts, including: a thickener; a base oil; and an organic sulfur compound, wherein the organic sulfur compound is a compound having no heterocycle containing nitrogen in a molecule thereof.

Provided is a lubricating oil composition, which has low viscosity but also prolonged anti-shudder life without reduction of intermetallic friction coefficient. The lubricating oil composition is characterized in comprising (A) a lubricating base oil, and (C) (C-1) a borated succinimide compound with a mass average molecular weight of 4,000-7,000 and (C-2) a borated succinimide compound with a mass average molecular weight of greater than 7,000-10,000.