A forged crankshaft (1) includes a carbon steel containing S, wherein in a portion corresponding to a machined outer circumferential surface of a shaft part such as journals (J), crank pins (P), a front part (Fr), and a flange (Fl), a ratio x/y of an area rate x of sulfide in a position (X) corresponding to a parting surface of a die for finish forging to an area rate y of sulfide in a position (Y) corresponding to a bottom of a die impression of the die for finish forging is equal to or lower than 1.5. The forged crankshaft (1) can avoid an occurrence of machined surface cracks on the journals (J) and the crank pins (P) after the outer circumferential surface is machined.

A tapered roller bearing includes an outer ring, an inner ring, a plurality of tapered rollers, and a holder. A nitrogen concentration in a surface layer portion under a contact surface is 0.3 mass % or more. The holder includes a small annular portion, a large annular portion, and a plurality of column portions. A pocket has a trapezoidal shape in which a portion housing a small diameter side of the tapered roller is located on a reduced width side while a portion housing a large diameter side of the tapered roller is located on an increased width side. Each of the column portions on the reduced width side of the pocket is provided with a cutout.

The invention relates to a crankshaft (1) for a reciprocating piston internal combustion engine having at least two main bearings (2) a crank pin (3). Crankshaft flanges (4) are arranged between each of the main bearings and the crank pin and connect the main bearings to the crank pin. The crankshaft has at least one ring gear (5) spaced apart axially from a main bearing for a drive of a chain drive. A crankshaft surface between the main bearing and the first ring gear has an averaged roughness depth R z of less than 3 micrometres. Due to the configuration of the crankshaft according to the invention for a reciprocating piston internal combustion engine, higher torsional moments can be transmitted or the crankshaft can be designed to be lighter in the area having the higher surface quality.

A bearing unit having a stationary radially outer ring provided with a raceway, a radially inner ring rotatable about a central rotation axis (X) of the bearing unit and provided with a raceway, a row of rolling elements interposed between the radially outer ring and the radially inner ring, at least one sealing device mounted by means of interference on the radially outer ring and in sliding contact with the radially inner ring, wherein both the radially outer ring and the radially inner ring are made of low carbon steel with a minimum percentage by weight of carbon equal to 0.42%, and a central portion of the radially outer ring situated along the raceway and a central portion of the radially inner ring situated along the raceway are heat treated by means of induction hardening.

A rolling sliding member includes a base part and a surface layer. The base part has a composition that includes 0.30 mass % to 0.45 mass % of carbon, 0.15 mass % to 0.45 mass % of silicon, 0.40 to 1.50 mass % of manganese, 0.60 mass % to 2.00 mass % of chromium, 0.10 mass % to 0.35 mass % of molybdenum, 0.20 mass % to 0.40 mass % of vanadium, and 0.005 mass % to 0.100 mass % of aluminum, and a remainder of iron and inevitable impurities. The surface layer is positioned around the base part. The surface layer has a Vickers hardness of 700 to 800 and a retained austenite content of 25 volume % to 50 volume %. The thickness of a grain boundary oxide layer satisfies Formula: thickness of grain boundary oxide layer≤equivalent diameter of rolling sliding member×1.4×10.sup.−3.

A heat treatment process for through hardening results in high surface compressive stresses. The method includes heating a steel component to a first temperature, quenching the steel component to a second temperature, maintaining the steel component at the second temperature for a first duration of time, heating the steel component to a third temperature, maintaining the steel component at the third temperature for a second duration of time, and quenching the steel component to a fourth temperature when austenite to martensite+bainite or bainite transformation is at least 10% but less than 85% complete.

A rolling-sliding member that is high in hardness and continues to have a passivation film reliably even after being subjected to a process that does not require any processing for removal of scale etc., as well as a rolling bearing using the same and a method for manufacturing the rolling-sliding member.

A bearing bushing for a track has an annular shape including an inner peripheral surface, an outer peripheral surface, a first end face, and a second end face located axially opposite the first end face. The bearing bushing for a track includes an inner peripheral surface-side hardened layer formed to include the inner peripheral surface, an outer peripheral surface-side hardened layer formed to include the outer peripheral surface, a first end face-side hardened layer formed to include the first end face and having a region with a hardness of 63 HRC or more that has a thickness of 3 mm or more from the first end face, and an unhardened region lower in hardness than the inner peripheral surface-side hardened layer, the outer peripheral surface-side hardened layer, and the first end face-side hardened layer, and including at least the second end face. The bearing bushing is made of steel.

A bearing component such as a bearing ring includes a metallic base body and at least one alloy steel coating on the base body, the coating being applied to the base body by deposition welding. The base body is preferably non-alloy steel or cast iron, and the alloy includes at least one carbide-forming transition metal such as niobium, tantalum, zirconium, titanium, hafnium, tungsten, molybdenum, vanadium, or manganese. The coating can form a raceway of the bearing component or a structural element such as a flange. Also a method of forming such a bearing component is provided.

A sintered bearing bush material for a sliding bearing may include: 0.5 to 1.7 percentage by weight carbon; 0.2 to 1.2 percentage by weight manganese; 0.2 to 1.2 percentage by weight sulphur; 1.2 to 2.4 percentage by weight nickel; 1.0 to 2.1 percentage by weight molybdenum; 3.0 to 7.0 percentage by weight copper; 0.2 to 1.2 percentage by weight tin; 0 to 0.8 percentage by weight phosphorus; and a residual component.