Provided is a lubricating oil composition for an internal combustion engine containing: (A) a lubricant base oil with a kinematic viscosity at 100? C. of 2.0 mm.sup.2/s to 5.0 mm.sup.2/s; (B) 50 mass ppm to 2000 mass ppm of a molybdenum-based friction modifier based on the total amount of the composition as an amount of molybdenum; (C) a nitrogen-containing ashless friction modifier; (D) a succinimide or a derivative thereof as a dispersant; (E) an amine ashless antioxidant as an antioxidant; and (F) 1000 mass ppm to 2200 mass ppm of a metallic detergent based on the total amount of the composition as an amount of metal, wherein the amount of sulfated ash in the composition is 0.9 mass % or less, and a nitrogen management index is 0.60 or less. Provided is a lubricating oil composition for an internal combustion engine having improved fuel efficiency and oxidative stability, while maintaining low amount of sulfated ash.

Provided is a lubricating oil composition for an internal combustion engine containing: (A) a lubricant base oil with a kinematic viscosity at 100? C. of 2.0 mm.sup.2/s to 5.0 mm.sup.2/s; (B) 50 mass ppm to 2000 mass ppm of a molybdenum-based friction modifier based on the total amount of the composition as an amount of molybdenum; (C) a nitrogen-containing ashless friction modifier; (D) a succinimide or a derivative thereof as a dispersant; (E) an amine ashless antioxidant as an antioxidant; and (F) 1000 mass ppm to 2200 mass ppm of a metallic detergent based on the total amount of the composition as an amount of metal, wherein the amount of sulfated ash in the composition is 0.9 mass % or less, and a nitrogen management index is 0.60 or less. Provided is a lubricating oil composition for an internal combustion engine having improved fuel efficiency and oxidative stability, while maintaining low amount of sulfated ash.

A rolling bearing (1) includes an outer ring (2), an inner ring (4), and a plurality of rolling elements (6) arranged between the outer and inner ring (2, 4). The rolling bearing (1) is provided with lubricant. The outer ring (2) has an outer contact width (b.sub.o) between the outer ring (2) and the rolling elements (6). The inner ring (4) has an inner contact width (b.sub.i) between the inner ring (4) and the rolling elements (6). A ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 1.65 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 0.97 and smaller than 1.06 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is smaller than 0.68.

A rolling bearing (1) includes an outer ring (2), an inner ring (4), and a plurality of rolling elements (6) arranged between the outer and inner ring (2, 4). The rolling bearing (1) is provided with lubricant. The outer ring (2) has an outer contact width (b.sub.o) between the outer ring (2) and the rolling elements (6). The inner ring (4) has an inner contact width (b.sub.i) between the inner ring (4) and the rolling elements (6). A ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 1.65 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 0.97 and smaller than 1.06 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is smaller than 0.68.

A tribological system, including a main body and a sandwich lubrication, wherein the sandwich lubrication includes a binder-free solid lubricant layer including a solid lubricant, and a lubricant layer including a lubricant. The binder-free solid lubricant layer and the lubricant layer are present as separate layers on the main body and the mass ratio of solid lubricant to lubricant is at most 0.05:1. The solid lubricant includes polytetrafluoroethylene (PTFE), metal sulfide, graphite, graphene, boron nitride (hexagonal), calcium phosphate, silicate, layered silicate, or mixtures thereof.

A tribological system, including a main body and a sandwich lubrication, wherein the sandwich lubrication includes a binder-free solid lubricant layer including a solid lubricant, and a lubricant layer including a lubricant. The binder-free solid lubricant layer and the lubricant layer are present as separate layers on the main body and the mass ratio of solid lubricant to lubricant is at most 0.05:1. The solid lubricant includes polytetrafluoroethylene (PTFE), metal sulfide, graphite, graphene, boron nitride (hexagonal), calcium phosphate, silicate, layered silicate, or mixtures thereof.

Provided is a lubricating oil composition for an internal combustion engine containing: (A) a lubricant base oil with a kinematic viscosity at 100 C. of 2.0 mm.sup.2/s to 5.0 mm.sup.2/s; (B) 50 mass ppm to 2000 mass ppm of a molybdenum-based friction modifier based on the total amount of the composition as an amount of molybdenum; (C) a nitrogen-containing ashless friction modifier; (D) a succinimide or a derivative thereof as a dispersant; (E) an amine ashless antioxidant as an antioxidant; and (F) 1000 mass ppm to 2200 mass ppm of a metallic detergent based on the total amount of the composition as an amount of metal, wherein the amount of sulfated ash in the composition is 0.9 mass % or less, and a nitrogen management index is 0.60 or less. Provided is a lubricating oil composition for an internal combustion engine having improved fuel efficiency and oxidative stability, while maintaining low amount of sulfated ash.

Provided is a lubricating oil composition for an internal combustion engine containing: (A) a lubricant base oil with a kinematic viscosity at 100 C. of 2.0 mm.sup.2/s to 5.0 mm.sup.2/s; (B) 50 mass ppm to 2000 mass ppm of a molybdenum-based friction modifier based on the total amount of the composition as an amount of molybdenum; (C) a nitrogen-containing ashless friction modifier; (D) a succinimide or a derivative thereof as a dispersant; (E) an amine ashless antioxidant as an antioxidant; and (F) 1000 mass ppm to 2200 mass ppm of a metallic detergent based on the total amount of the composition as an amount of metal, wherein the amount of sulfated ash in the composition is 0.9 mass % or less, and a nitrogen management index is 0.60 or less. Provided is a lubricating oil composition for an internal combustion engine having improved fuel efficiency and oxidative stability, while maintaining low amount of sulfated ash.

A bearing device 1 for a vehicle wheel comprises an outer ring 2 having a double row of outer raceway surfaces 2c, 2d on the inner circumference, a hub ring 3 and an inner ring 4, having a double row of inner raceway surfaces 3d, 4a, and a plurality of tapered rollers 51, the inner raceway surfaces 3d, 4a being integrally formed with large flange sections 3e, 4b that come into sliding contact with large-diameter-side end surfaces 51a of the tapered rollers 51, wherein the large flange sections 3e, 4b have an arithmetic mean roughness Ra of 0.08 m or less, and a base oil of grease to be filled in the space surrounding the tapered rollers 51 has a kinematic viscosity at 40 C. of 40 to 80 mm.sup.2/s.

A bearing device 1 for a vehicle wheel comprises an outer ring 2 having a double row of outer raceway surfaces 2c, 2d on the inner circumference, a hub ring 3 and an inner ring 4, having a double row of inner raceway surfaces 3d, 4a, and a plurality of tapered rollers 51, the inner raceway surfaces 3d, 4a being integrally formed with large flange sections 3e, 4b that come into sliding contact with large-diameter-side end surfaces 51a of the tapered rollers 51, wherein the large flange sections 3e, 4b have an arithmetic mean roughness Ra of 0.08 m or less, and a base oil of grease to be filled in the space surrounding the tapered rollers 51 has a kinematic viscosity at 40 C. of 40 to 80 mm.sup.2/s.