Abstract: A lubricating oil composition for a metal belt-type continuously variable transmission with a high metal-to-metal friction coefficient and excellent anti-fatigue and anti-seizure properties is provided. The composition contains a lubricating base oil and (A) a high overbased alkaline earth metal sulfonate having a base number of 300 to 500 mgKOH/g in an amount of 0.01 to 0.03 percent by mass as alkaline earth metal, (B) a low overbased alkaline earth metal sulfonate with a base number of 0 to 40 mgKOH/g in an amount of 0.005 to 0.015 percent by mass as alkaline earth metal, and (C) a sulfur-containing phosphite ester in an amount of 0.02 to 0.06 percent by mass as phosphorus. The ratio ([M]/[P]) of the content of (B) as alkaline earth metal ([M]) to the content of (C) as phosphorus ([P]) is 0.15 or greater.

Abstract: Provided is a compound which can increase all of the shudder prevention lifetime, transmission characteristic and transmission torque capacity to satisfactory levels when contained in a lubricating oil. Provided are a succinimide compound represented by the following general formula (1), and a friction modifier and a lubricating oil composition containing the succinimide compound. (In the formula (1), R represents a hydrocarbyl group having 8 to 30 carbon atoms; and n represents an integer of 1 to 7.

Abstract: A continuously variable transmission oil composition comprising a base oil and at least one phosphorous compound in such an amount that the phosphorus in the phosphorus compound accounts for 0.005 to 0.15 mass % of the total mass of the composition and wherein the continuously variable transmission oil composition has a friction coefficient from 0.146 to 0.164 when tested according to ASTM D2714.

Abstract: Provided is a continuously variable transmission oil composition that can markedly increase the coefficient of friction between a metal belt or a chain and a pulley, that can maintain the high coefficient of friction over a long period of time, and that causes no clogging of the clutch plate. The continuously variable transmission oil composition includes 0.005-0.15 mass %, as phosphorous compound-derived phosphorus content with respect to the total amount of the composition, of at least one type of phosphorous compound represented by general formula (1) in a lubricating oil base. (1) In general formula (1), R1, R2, R3 and R4 each represents a hydrocarbyl with carbon number 1-30 or a hydrogen atom, R5 represents a hydrocarbylene group with carbon number 1-30, X1 and X2 represent an oxygen atom or a sulfur atom, and n represents an integer 1-10.