An object of the present invention is to provide a grease composition which has little influence on the environment and has good rust prevention and water resistance against salt water such as sea water. The grease composition comprises a biodegradable base oil and a rust-preventive agent comprising a calcium sulfonate complex and a sorbitan fatty acid ester, wherein a total content of biodegradable organic substances in the grease composition is 75% by mass or more, and wherein a content of the rust-preventive agent is 2.5 to 30% by mass.

A lubricant composition according to the present invention contains a fatty acid metal salt, a metal dithiocarbamate, and an additive having an effect of increasing an acid value of the lubricant composition, whereby fretting resistance performances are further improved.

The rolling bearing of the present invention is lubricated with a lubricant composition which contains a fatty acid metal salt, a metal dithiocarbamate, a phosphorous-type additive, and a basic additive, and which has a total acid value of 3.7 mgKOH/g or more. The rolling bearing makes it possible to further improve anti-fretting performance, and to reduce a decrease in fretting resistance even when used under the circumstance that fluorine-type grease penetrates into the bearing using urea-type grease.

A lubricating oil composition for an internal combustion engine, the composition including: a lubricating base oil comprising at least one mineral base oil or at least one synthetic base oil or any combination thereof, the lubricating base oil having a kinematic viscosity at 100 C. of 4.0 to 4.5 mm.sup.2/s and a NOACK evaporation loss at 250 C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium on the basis of the total mass of the composition; and optionally (C) a viscosity index improver in an amount of less than 1 mass % on the basis of the total mass of the composition.

An object of the present invention is to provide a lubricating oil composition particularly excellent in viscosity characteristics at a low temperature. The present invention provides: a lubricating oil composition including a polymer (A) and a base oil (B), wherein the polymer (A) satisfies the following requirement (A-1), and the content ratio of the polymer (A) and the base oil (B) is such that the ratio of a resin (A) is within the range of from 0.1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the polymer (A) and the base oil (B). (A-1) The polymer (A) is a polymer containing a structural unit derived from an -olefin having 20 or less carbon atoms.

A sealed refrigerant compressor (100) includes: a compression element (107) accommodated in a sealed container (101) and configured to compress a refrigerant; and an electric element (106) configured to drive the compression element (107). Lubricating oil (103) is stored in the sealed container (101). The lubricating oil (103) is mixed oil constituted by at least mineral oil and synthetic oil. Kinetic viscosity of the lubricating oil (103) at 40 C. falls within a range of 0.1 to 5.1 mm.sup.2/s, and a flash point of the lubricating oil (103) is 110 C. or more.

The present application relates to a lubricant composition comprising: at least one base oil; from 0.05 to 1.5% by weight of an organomolybdenum compound; and from 0.005 to 1% by weight of TiO.sub.2 particles.

An ashless lubricating oil having a lubricating oil base stock as a major component, and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components. The lubricating oil base stock is a monoester obtained by a) reacting one Guerbet alcohol of 8 to 20 carbon atoms with a Guerbet acid, a linear or branched acid of 6 to 20 carbon atoms or b) reacting one linear or branched alcohol with at least 6 to 20 carbon atoms with a Guerbet acid of 8 to 20 carbon atoms. The lubricating oil base stock is present in an amount from 30 to 99.8 wt. % of the oil. A method for improving oxidative stability and high temperature stability of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using the ashless lubricating oil.

An ashless lubricating oil having a lubricating oil base stock as a major component, and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components. The lubricating oil base stock is a branched polyol ester. The lubricating oil base stock is present in an amount from about 30 to about 99.8 mass percent, based on the total mass of the ashless lubricating oil. A method for improving oxidative stability and high temperature stability of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using the ashless lubricating oil. The ashless lubricating oil is useful as a passenger vehicle engine oil (PVEO).

Provided are: a lubricating oil composition containing a mineral oil (A) having a kinematic viscosity at 40 C. of 5 to 15 mm.sup.2/s and a flash point of 180 C. or higher, a synthetic oil (B) having a kinematic viscosity at 40 C. of 5 to 15 mm.sup.2/s and a flash point of 190 C. or higher, an amide compound (C) and a polyol ester compound (D), which has a low viscosity and fuel saving performance, which can be used in high-temperature environments, and which has excellent gear anti-seizing property and anti-shudder performance; and a lubrication method and a transmission using the lubricating oil composition.