The invention provides a grease composition for a speed reducer part of an on-vehicle electric component, the grease composition containing a base oil and a thickener, wherein the base oil is poly-α-olefin or a mixed oil of poly-α-olefin and mineral oil having a kinematic viscosity of 4 to 19 mm.sup.2/s at 100° C. and a pour point of −30° C. or lower, the thickener is a mixture of a diurea compound expressed by formula (1) and a diurea compound expressed by formula (2)

R.sub.1—NHCONH—R.sub.2—NHCONH—R.sub.1  (1)

R.sub.3—NHCONH—R.sub.2—NHCONH—R.sub.3  (2)

wherein R.sub.1 is a straight-chain alkyl group having 8 or 18 carbon atoms, R.sub.2 is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and R.sub.3 is an aryl group having 6 to 7 carbon atoms, and a penetration of the grease composition is 220 to 280.

A grease composition may contain a base oil (A) and a urea-based thickener (B). Particles containing the urea-based thickener (B) in the grease composition may satisfy requirement (I). The base oil (A) may be a mixed base oil containing a high-viscosity base oil (A1) having a kinematic viscosity at 40° C. of 250 mm.sup.2/s to 550 mm.sup.2/s, a low-viscosity base oil (A2) having a kinematic viscosity at 40° C. of 5.0 mm.sup.2/s to 110 mm.sup.2/s, and an ultra-high viscosity hydrocarbon-based synthetic oil (A3) having a number average molecular weight (Mn) of 2,500 to 4,500 and a kinematic viscosity at 40° C. of 25,000 mm.sup.2/s to 50,000 mm.sup.2/s. The base oil (A) may have a kinematic viscosity at 40° C. of 25 mm.sup.2/s to 105 mm.sup.2/s and a viscosity index of 120 or more. Both low-temperature characteristics and a lubricating life can be achieved.

One aspect of the disclosure relates to a sliding member. The sliding member includes: a first sliding portion having a first lubricant placed between first parts of a first friction sliding mechanism; a second sliding portion having a second lubricant placed between second parts of a second friction sliding mechanism; and a third sliding portion having a third lubricant placed between third parts of a third friction sliding mechanism. The first sliding portion is in contact with the third lubricant, and the second sliding portion is not in contact with the third lubricant. The second lubricant contains an additive containing conductive carbon, and the third lubricant contains no conductive carbon. The second lubricant contains a relatively larger amount of the conductive carbon than the first lubricant.

A grease composition which contains a base oil (A), a urea-based thickener (B), a sarcosine derivative (C), and a fatty acid zinc salt (D), wherein particles containing the urea-based thickener (B) in the grease composition satisfies Requirement (I). The base oil (A) is a blended base oil containing a high viscosity hydrocarbon-based synthetic oil having a specific kinematic viscosity (A1). A low viscosity hydrocarbon-based synthetic oil having a specific kinematic viscosity (A2). An ultra-high viscosity hydrocarbon-based synthetic oil has a number average molecular weight (Mn) of 2,500 to 4,500 and a specific kinematic viscosity (A3). A 40° C. kinematic viscosity of the base oil (A) is 500 mm.sup.2/s to 1,500 mm.sup.2/s. A viscosity index of the base oil (A) is 140 or more. A content of the fatty acid zinc salt (D) is 10 mass % to 20 mass % based on a total amount of the grease composition.

A tribological system, comprising a main body and a sandwich lubrication, in which the sandwich lubrication includes a binder-free solid lubricant layer comprising a solid lubricant, and a lubricant layer comprising a lubricant. The binder-free solid lubricant layer and the lubricant layer are present as separate layers on the main body and wherein the mass ratio of solid lubricant to lubricant is at most 0.05:1

In one or more embodiments, this application relates to tribotechnical additive and lubricant compositions based on self-assembled carbon nanoarchitectonics derived through nanoscale modifications of organosilane-functionalized nanocarbon with one or multiple combinations of organo-molybdenum, organo-boron, organo-sulfur, organo-phosphorus, and heterocyclic compounds. The novel lubricant is characterized by having a composition comprising (A) one or more types of the novel additive compositions, (B) Base oil//lubricant, and optionally (C) one or more additives selected from the group including antioxidants, dispersants, detergents, anti-wear additives, extreme pressure additives, friction modifiers, viscosity index modifiers, seal swell additives, defoamers, pour point depressants and corrosion/rust inhibitors. The selfassembled carbon nanoarchitectonics is expected to enhance the surface chemistry, antiwear, antifriction, antioxidancy, electrothermal, and corrosion inhibiting characteristics of the tribotechnical compositions for formulating high-quality solutions in a wide range of applications.

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.

This ball screw grease composition for a rack-assisted electric power steering contains a thickener, a base oil, and at least one compound selected from the group consisting of a Ca sulfonates, fatty acids, and triglycerides, wherein the kinematic viscosity of the base oil at 40° C. is 4-100 mm2/s, and the worked penetration of the composition is 265-385.

The invention provides a grease composition for lubricating resins which contains a base oil, a diurea compound represented by formula (I) as a thickener: R.sup.1—NHCONH —R.sup.2—NHCONH—R.sup.3 (I) (wherein R.sup.2 represents a bivalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and R.sup.1 and R.sup.3 each independently represent a straight-chain or branched alkyl group having 8 to 22 carbon atoms), and a chained hydrocarbon polymer having a weight-average molecular weight of 20,000 to 300,000.

A rolling bearing is filled with a grease composition that contains a fluorine-based grease including a fluorine-based base oil and a fluorine-based thickener, a non-fluorine-based grease including a non-fluorine-based base oil and a non-fluorine-based thickener, and an additive serving as a dispersant. The non-fluorine-based thickener includes at least one of aliphatic-aromatic urea, alicyclic-aliphatic urea and aliphatic urea. The dispersant includes at least one of polycarboxylic acid metal salt, fluorine-containing group/lipophilic group-containing oligomer, fluorinated ether diamide, and organic acid metal salt.