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.

An annular ring having a contact portion, a raceway and a squirrel-type cage secured to the contact portion. The contact portion is formed from a first metal material, and the squirrel cage is formed from a second composite-type material including a matrix in which reinforcing fibres are embedded, the pierced portion of the squirrel cage being attached to an outer surface of the contact portion. Also, a bearing assembly with rolling elements having an outer ring, an inner ring coaxial with the outer ring, and a plurality of rolling elements housed between the raceway of the contact portion of the outer ring and a raceway of the inner ring.

The invention relates to the technical field of microstructure refinement and homogenization of bearing steel, and specifically relates to a high-carbon bearing steel and a method of preparing same. The high-carbon bearing steel of the invention has the following chemical composition: C: 0.80˜1.20 wt %, Cr: 0.40˜2.0 wt %, Mn: 0.15˜0.75 wt %, Si: 0.15˜0.75 wt %, Nb: 0˜0.20 wt %, Mo: 0˜0.20 wt %, V: 0˜0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities; the contents of Nb, Mo and V are not 0 at the same time. According to the invention, microalloying elements such as Nb, Mo and V, in combination with other elements, are added into the high-carbon bearing steel to effectively refine the bearing steel matrix and promote the precipitation of a large amount of nano-carbides, thereby enhancing the contact fatigue life of the high-carbon bearing steel.

A bearing component composed of a chromium-molybdenum-vanadium alloyed tool steel is produced by a process that includes: (i) performing a first preheating within a temperature range of 600-650° C., (ii) performing a second preheating within a temperature range of 850-900° C., (iii) austenitizing in vacuum at 1000-1180° C. for 20-40 min, (iv) gas quenching at a minimum of 4-5 bar overpressure, and (v) tempering by performing either a double temper at 520-560° C. for 1.5-2.5 hours in each temper, or a triple temper at 520-560° C. for 0.5-1.5 hours in each temper. The steel alloy may be composed (in mass percent) of 1.32-1.45 C, 0.32-0.50 Si, 0.26-0.48 Mn, 4.0-4.85 Cr, 3.35-3.55 Mo, 3.55-3.85 V, 0-0.13 W, 0-0.20 Ni, 0-0.15 Cu, 0-0.8 Co, 0-0.03 P, and 0-0.03 S, the balance being iron and unavoidable impurities. Mo may be replaced with W or vice versa in a replacement ratio Mo:W of 1:2.

Steel for a crankshaft includes 0.37 to 0.42 wt % of carbon (C), 0.55 to 0.70 wt % of silicon (Si), 1.45 to 1.65 wt % of manganese (Mn), 0.025 wt % or less (excluding 0 wt %) of phosphorus (P), 0.020 to 0.035 wt % of sulfur (S), 0.15 to 0.30 wt % of chromium (Cr), 0.035 to 0.055% of vanadium (V), and the remainder of Fe and other inevitable impurities. The steel for a crankshaft has strength that is maintained high even when reducing the amount of vanadium.

A thrust roller bearing includes a plurality of radially arranged rollers, and a pair of annular washers having raceway surfaces on which the rollers roll, the raceway surfaces being arranged to face each other. The roller is made of high-carbon chromium bearing steel, and contains 1.1 mass % to 1.6 mass % of carbon and 0.1 mass % to 0.6 mass % of nitrogen in a range of 0.1 mm from a surface. A surface compressive residual stress is smaller than −900 MPa, a surface roughness is 0.01 to 0.10 in terms of Rvk and 0.01 to 0.08 in terms of Rk, and a Vickers hardness of the surface is 860 to 980. At least one of the washers is made of carbon steel, and surface roughnesses of the raceway surfaces are 0.05 to 0.20 in terms of Rvk and 0.08 to 0.15 in terms of Rk.

Provided is a steering function-equipped hub unit including: a hub unit body including a hub bearing; a unit support member configured to be provided to a chassis frame component, the unit support member supporting the hub unit body such that the hub unit body is rotatable about a turning axis extending in a vertical direction; and a steering actuator configured to rotationally drive the hub unit body about the turning axis, wherein the hub bearing includes an outer race integrally provided with turning shaft parts protruding upward and downward in the vertical direction on an outer peripheral surface of the outer race, each of the turning shaft parts having an axis coinciding with the turning axis, and the hub unit body is rotatably supported by the unit support member through the turning shaft parts.

A reduction gear includes an external gear, an internal gear which meshes with the external gear, a first member which synchronizes with a rotation of the external gear, a second member which synchronizes with a rotation of the internal gear, and a main bearing which is disposed between the first member and the second member, in which one of the first member and the second member is connected to a driven member and the other is fixed to an external member, and the first member, the second member, and the main bearing are formed of a material having a larger Young's modulus and larger specific gravity than those of a material constituting the external gear and the internal gear.

In one aspect of the present invention, a method for manufacturing a bearing component includes: a preparation step of preparing a ring-shaped member of steel having a radially inner surface, a radially outer surface, and a thickness which is a distance between the radially inner surface and the radially outer surface; and a heat treatment step of performing a heat treatment to locally heat one of the radially inner surface and the radially outer surface to a heat treatment temperature and subsequently cool the one of the radially inner surface and the radially outer surface, the method satisfying S≥930/(0.3477 W.sup.2−1.594 W−0.804), where S represents an average temperature increasing rate (unit: ° C./sec) applied when the surface is heated and W represents the thickness (unit: mm).

A method and system for manufacturing a cast iron crankshaft for a vehicle are provided. The system comprises a molding unit arranged to form a negative sand cast mold of the cast iron crankshaft. The mold comprising at least one molded cavity having a pattern with dimensions of the cast iron crankshaft. The system further comprises a feeding mechanism comprising a riser having a connector through which molten metallic material flows to the cast mold. The feeding mechanism feeds the molten metallic material at a riser connection angle in the at least one mold cavity. The riser connection angle corresponds to a connector modulus. The connector modulus is 20% greater than a cast modulus. The riser geometry corresponds to a riser modulus. The riser modulus is 20% greater than the connector modulus. The system further comprises a furnace, a cooling area, a separation unit, a controller and a power source.