The invention relates to a carburizing bearing steel and a preparation method thereof. The carburizing bearing steel of the invention comprises: 0.18˜0.24 wt % of C, 0.4˜0.6 wt % of Cr, 0.20˜0.40 wt % of Si, 0.40˜0.70 wt % of Mn, 1.6˜2.2 wt % of Ni, 0.15˜0.35 wt % of Mo, 0.001˜0.01 wt % of S, 0.001˜0.015 wt % of P, 0˜0.20 wt % of Nb, 0˜0.20 wt % of V and the remaining is iron, wherein the contents of Nb and V are not 0 at the same time. In the invention, an appropriate amount of Nb and V is added in combination with other elements so as to refine the grain size, inhibit the generation of large granular carbides in the steel during carburization and improve the uniformity of the microstructure of steel materials, thus further enhancing the contact fatigue life of the carburizing bearing steel.

A roller retainer cage for a roller thrust bearing, including a first cage half with an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, a second cage half including an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, wherein the first flange of the first cage half is disposed radially-outwardly of the first flange of the second cage half, the second flange of the first cage half is disposed radially-inwardly of the second flange of the second cage half, and the first cage half is comprised of a through-hardened metal.

A carburized shaft part having a predetermined composition, a C content at a surface layer part of a mass % of 0.60 to 1.00%, at least one hole at an outer circumferential surface, a total volume ratio of martensite and retained austenite of 97% or more at a structure at a position of a 1 mm depth from the outer circumferential surface in an axial direction of the hole and a position of a 20 μm depth from the surface of the hole, a maximum retained austenite volume ratio (R1) of 10.0 to 30.0% at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a range up to a 200 μm depth from the surface of the hole, and a retained austenite reduction ratio of 20% or more found from R1 and the retained austenite volume ratio (R2) at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a position of a 20 μm depth from the surface of the hole by the formula (A): Δγ=(R1−R)/R1×100.

A member for guiding an element mobile in oscillation or rotation is presented. The member has a body made of a hardened metallic material, provided with a bore for assembling the mobile element, having cavities that are distributed discontinuously in the bore and capable of acting as grease reserves, and having optional grease supply. In the bore are defined a bearing surface outside of the cavities and the grease supply, and a non-bearing surface in the cavities and the grease supply. The bore includes at least one zone with: cavities having a depth of between 2 and 5 mm, and a quantity of grease in the cavities per bearing surface of between 0.05 and 0.3 g/cm.sup.2. A mechanical system having such a member and a method for manufacturing such a member is also contemplated.

An inner ring or and outer ring for a roller bearing includes: 0.30-0.45 wt. % carbon, 0.1-0.7 wt. % silicon, 0.6-0.9 wt. % manganese, 0.9-1.2 wt. % chromium, 0.15-0.7 wt. % molybdenum, 0-2.0 wt. % nickel, 0-0.02 wt. % phosphorus, and 0 -0.02 wt. % sulfur, the balance being iron and unavoidable impurities. The microstructure of the steel composition contains bainite, and a carbonitrided case layer is provided on a surface of the inner ring or outer ring.

A link component (150) with an oil hole (150E) is attached to a crankshaft (106) of an internal combustion engine (E), and the oil hole (150E) allows communication from an outside to the crankshaft (106) side. The oil hole (150E) has an inclined surface (150F) along an opening rim on the crankshaft (106) side. A surface other than the oil hole (150E) has a carbon concentration of 0.5 wt % or more. The inclined surface (150F) has a carbon concentration within a range of 0.7 wt % or more and 0.9 wt % or less. Production cost is suppressed, and at the same time, damage is prevented by increasing resistance of the oil-hole part on which stress is liable to concentrate.

A fastening structure (105) includes a pair of fastening members (105A) joined to each other, which is coupled with a bolt. The fastening member (105) is made of steel. A surface other than joint surfaces (Sa) has a Rockwell hardness of 50 HRC or more. The joint surfaces (Sa) have a Rockwell hardness of 30 HRC or more and less than 50 HRC. The joint surfaces (Sa) have an arithmetic mean roughness (Ra) of 0.2 μm or more and 0.5 μm or less. Production cost is suppressed, and at the same time, bending fatigue strength is secured and secondary damage due to abrasion powder generated by fretting is prevented.

A tapered roller bearing for an automobile includes an inner ring including a raceway surface having a tapered shape on an outer periphery, an outer ring including a raceway surface having a tapered shape on an inner periphery, a plurality of tapered rollers incorporated into a space defined between the raceway surfaces, and a retainer configured to receive the tapered rollers. The inner and outer rings are each made of carburized steel, and the raceway surfaces of the inner and outer rings each have a straight generating line shape. The tapered rollers each are made of high carbon chromium bearing steel, and each have a rolling surface including a straight portion, which is formed at a center portion in an axial direction, and crowning portions, which extend from the straight portion to both end portions. The crowning portions are each formed of logarithmic crowning.

A tapered roller bearing for an automobile includes an inner ring including a raceway surface having a tapered shape on an outer periphery, an outer ring including a raceway surface having a tapered shape on an inner periphery, a plurality of tapered rollers incorporated into a space defined between the raceway surfaces, and a retainer configured to receive the tapered rollers. The inner and outer rings are each made of carburized steel, and the raceway surfaces of the inner and outer rings each have a straight generating line shape. The tapered rollers each are made of high carbon chromium bearing steel, and each have a rolling surface including a straight portion, which is formed at a center portion in an axial direction, and crowning portions, which extend from the straight portion to both end portions. The crowning portions are each formed of logarithmic crowning.

A link component (150) with an oil hole (150E) is attached to a crankshaft (106) of an internal combustion engine (E), and the oil hole (150E) allows communication from an outside to the crankshaft (106) side. The oil hole (150E) has an inclined surface (150F) along an opening rim on the crankshaft (106) side. A surface other than the oil hole (150E) has a carbon concentration of 0.5 wt % or more. The inclined surface (150F) has a carbon concentration within a range of 0.7 wt % or more and 0.9 wt % or less. Production cost is suppressed, and at the same time, damage is prevented by increasing resistance of the oil-hole part on which stress is liable to concentrate.