Abstract: Provided is a rolling device in which hydrogen is not easily accumulated within a roller element made of steel, such as an inner race and an outer race, and premature separation due to hydrogen embrittlement is prevented from occurring. A rolling bearing 1 having an inner race 2, an outer race 3, and rolling bodies 4, and at least one selected from the inner race 2, the outer race 3, and the rolling bodies 4 is made of predetermined steel. At least a part of oxide-based inclusions included in the steel is covered by MnS, and a ratio of a number of oxide-based inclusions covered by MnS is over 40% of a total number of oxide-based inclusions having maximum diameter of 3 ?m or greater in the steel.

Abstract: A bearing component composed of steel which contains carbon not less than 0.95 mass % and not more than 1.1 mass %, silicon less than 0.3 mass %, manganese less than 0.5 mass %, sulfur less than 0.008 mass %, and chromium not less than 1.4 mass % and less than 1.6 mass % and is composed of remainder iron and an impurity and having a carbonitrided layer formed at a surface portion including a contact surface which is a surface in contact with other components is provided. An average concentration of nitrogen in the surface portion is not lower than 0.3 mass % and not higher than 0.6 mass % and variation in nitrogen concentration in the surface portion is not higher than 0.1 mass %. An amount of retained austenite in the surface portion is not greater than 8 volume %.

Abstract: A bearing component composed of steel which contains carbon not less than 0.95 mass % and not more than 1.1 mass %, silicon less than 0.3 mass %, manganese less than 0.5 mass %, sulfur less than 0.008 mass %, and chromium not less than 1.4 mass % and less than 1.6 mass % and is composed of remainder iron and an impurity and having a carbonitrided layer formed at a surface portion is provided. An average concentration of nitrogen in the surface portion is not lower than 0.3 mass % and not higher than 0.6 mass % and variation in nitrogen concentration is not higher than 0.1 mass %. An amount of retained austenite is not greater than 8 volume %. An area ratio of a precipitate in the inside where no carbonitrided layer is formed is not lower than 11%.

Abstract: Provided is a rolling device in which hydrogen is not easily accumulated within a roller element made of steel, such as an inner race and an outer race, and premature separation due to hydrogen embrittlement is prevented from occurring. A rolling bearing 1 having an inner race 2, an outer race 3, and rolling bodies 4, and at least one selected from the inner race 2, the outer race 3, and the rolling bodies 4 is made of predetermined steel. At least a part of oxide-based inclusions included in the steel is covered by MnS, and a ratio of a number of oxide-based inclusions covered by MnS is over 40% of a total number of oxide-based inclusions having maximum diameter of 3 ?m or greater in the steel.

Abstract: A bearing component composed of steel which contains carbon not less than 0.95 mass % and not more than 1.1 mass %, silicon less than 0.3 mass %, manganese less than 0.5 mass %, sulfur less than 0.008 mass %, and chromium not less than 1.4 mass % and less than 1.6 mass % and is composed of remainder iron and an impurity and having a carbonitrided layer formed at a surface portion including a contact surface which is a surface in contact with other components is provided. An average concentration of nitrogen in the surface portion is not lower than 0.3 mass % and not higher than 0.6 mass % and variation in nitrogen concentration in the surface portion is not higher than 0.1 mass %. An amount of retained austenite in the surface portion is not greater than 8 volume %.

Abstract: A status monitoring system for accurately determining the contaminant water concentration in a lubricant oil used in a rolling device includes a contaminant water concentration monitoring device configured to monitor the contaminant water concentration in the lubricant oil. The contaminant water concentration monitoring device includes an electrostatic capacitance detector and an oil temperature measuring instrument, which are configured to detect the electrostatic capacitance and the oil temperature of the lubricant oil, respectively, and a water concentration calculation section configured to calculate the contaminant water concentration from the detected electrostatic capacitance and oil temperature in accordance with a predetermined rule.

Abstract: A bearing component composed of steel which contains carbon not less than 0.95 mass % and not more than 1.1 mass %, silicon less than 0.3 mass %, manganese less than 0.5 mass %, sulfur less than 0.008 mass %, and chromium not less than 1.4 mass % and less than 1.6 mass % and is composed of remainder iron and an impurity and having a carbonitrided layer formed at a surface portion is provided. An average concentration of nitrogen in the surface portion is not lower than 0.3 mass % and not higher than 0.6 mass % and variation in nitrogen concentration is not higher than 0.1 mass %. An amount of retained austenite is not greater than 8 volume %. An area ratio of a precipitate in the inside where no carbonitrided layer is formed is not lower than 11%.

Abstract: A method of assessing the shear fatigue property of a metallic material that undergoes a rolling contact includes a testing step for determining the relation between the shear stress amplitude of a rolling contact metallic material and the number of loading by means of an ultrasonic torsional fatigue test, and a shear fatigue strength determining step for determining the shear fatigue strength ?lim within the ultra long life regime from the relation between the shear stress amplitude and the number of loadings, which relation has been determined during the test step, in accordance with a predetermined standard. It is a completely reversed torsional fatigue test, in which torsional vibrations, respective torsions in the positive rotational direction and reversed rotational direction of which are symmetrical relative to each other, are applied to a test piece.

Abstract: A bearing component (an outer ring, an inner ring, and a ball) is made of bearing steel, and has a surface layer portion that is nitrided and includes an outer ring raceway surface and an inner ring raceway surface or a rolling surface. A nitrogen concentration in the surface layer portion is 0.4 mass % or higher. An area ratio of a precipitate in an inner portion that is not nitrided is 11% or higher.

Abstract: In order to provide a status monitoring system for accurately determining the contaminant water concentration in a lubricant oil used in a rolling device, the provision is made of a contaminant water concentration monitoring device (6) configured to monitor the contaminant water concentration in the lubricant oil (5). The contaminant water concentration monitoring device (6) includes an electrostatic capacitance detector (7) and an oil temperature measuring instrument (8), which are configured to detect the electrostatic capacitance and the oil temperature of the lubricant oil (5), respectively, and a water concentration calculation section (9) configured to detect the contaminant water concentration from the detected electrostatic capacitance and oil temperature in accordance with a predetermined rule.

Abstract: Included are a testing step (S1) for determining the relation between the shear stress amplitude of a rolling contact metallic material and the number of loading by means of an ultrasonic torsional fatigue test, and a shear fatigue strength determining step (S2) for determining the shear fatigue strength ?lim, within the ultra long life regime from the relation between the shear stress amplitude and the number of loadings, which relation has been determined during the test step (S1), in accordance with a predetermined standard. It is a completely reversed torsional fatigue test, in which torsional vibrations, respective torsions in the positive rotational direction and reversed rotational direction of which are symmetrical relative to each other, are applied to a test piece (1).

Abstract: A power transmission shaft mitigates the concentration of both tensile stress and shear stress to achieve an improvement in terms of fatigue strength. A male spline section is formed on an outer periphery of the power transmission shaft. On a valley section of the male spline section, at an axially opposite end side portion thereof, there is provided a diameter-expanded section whose outer diameter dimension is gradually increased toward an axially opposite end. Rounded sections having a circular arc cross-section are provided on both circumferential sides of the diameter-expanded section. A radius of curvature of the rounded sections is gradually increased toward the axially opposite end.

Abstract: A substrate is immersed in a metal compound solution prepared by dissolving a plurality of metal compounds of metals differing from each other, to thereby form an alloy film having a desired alloy composition on the surface of the substrate.

Abstract: Provided is a power transmission shaft in which concentration of both tensile stress and shear stress is mitigated to achieve an improvement in terms of fatigue strength of a power transmission shaft. A male spline section (Sm) is formed on an outer periphery of the power transmission shaft. On a valley section (21) of the male spline section (Sm), at an axially opposite end side portion thereof, there is provided a diameter-expanded section (21b) whose outer diameter dimension is gradually increased toward an axially opposite end. Rounded sections (21b1) having a circular arc cross-section are provided on both circumferential sides of the diameter-expanded section (21b). A radius of curvature of the rounded sections (21b1) is gradually increased toward the axially opposite end.

Abstract: An inexpensive rolling bearing is proposed which can be used stably for a long time where the lubricating conditions are severe or bending stresses act. Inner and outer rings of rolling bearings mounted in a rocker arm of an automobile are made of high-carbon chrome bearing steel. They are subjected to heat treatment in which after carbonitriding, high-temperature tempering is carried out. Then they are induction hardened to impart resistance to material quality change and a compressive stress of not less than 200 MPa to the surface layer, thereby markedly improving the rolling contact fatigue life and the tension-compression fatigue strength while keeping the material cost as before. Thus, this bearing can be used stably for a long time even though it is a full complement type bearing, lubricating conditions tend to worsen and the outer ring is repeatedly subjected to bending stress from the cam.

Abstract: There is provided a rolling component formed of a steel material of the medium carbon steel level that provides a rolling life improved to be comparable to that of bearing steel and also provides improved characteristic against surface-cracking, and a power transmission component including the rolling component. To achieve this, the rolling component is formed of steel having an induction hardened portion having a stress intensity factor range associated with tension associated-fatigue crack extension that has a lower limit ?Kth of 6.2 Mpa?m.

Abstract: There is provided a rolling component formed of a steel material of the medium carbon steel level that provides a rolling life improved to be comparable to that of bearing steel and also provides improved characteristic against surface-cracking, and a power transmission component including the rolling component. To achieve this, the rolling component is formed of steel having an induction hardened portion having a stress intensity factor range associated with tension associated-fatigue crack extension that has a lower limit ?Kth of 6.2 Mpa?m.

Abstract: An inexpensive rolling bearing is proposed which can be used stably for a long time even for applications where the lubricating conditions are severe or bending stresses act. Inner and outer rings of rolling bearings mounted in a rocker arm of an automobile are made of high-carbon chrome bearing steel. They are subjected to heat treatment in which after carbonitriding, high-temperature tempering is carried out. Then they are induction hardened to impart resistance to material quality change and a compressive stress of not less than 200 MPa to the surface layer, thereby markedly improving the rolling contact fatigue life and the tension-compression fatigue strength while keeping the material cost as before. Thus, this bearing can be used stably for a long time even though it is a full compliment type, lubricating conditions tend to worsen and the outer ring is repeatedly subjected to bending stress from the cam.

Abstract: There can be provided a positive electrode active material for a secondary battery which is excellent in the charging and discharging cycle characteristics so that it retains high battery capacity that is comparable to the hitherto known LiNiO2 even by increasing the number of cycle, which has an improved cycle property (stability) at high temperature and which is a complex oxide represented by the general formula (I) LiyNi1−xCox1Mx2O2  (I) (wherein M represents at least one element selected from the group consisting of Al, Fe, Mn and B, y represents 0.9≦y≦1.3, x represents 0<x≦0.5, x1 represents 0<x1<0.5, x1+x2 x, when M is at least one element of Al, Fe and Mn, x2 represents 0<x2≦0.3, when M is B, x2 is 0<x2≦0.1, when M is the combination of B and at least one element of Al, Fe and Mn, x2 represents 0<x2<0.3 but the ratio occupied by B therein is in a range of from 0 to 0.1).

Abstract: A process for preparing a spinel lithium manganese complex oxide having the general formula LixMn2−yAlyO4 (wherein 0.9≦x≦1.1, and 0.002≦y≦0.5) the process comprising the steps of reacting a manganese complex hydroxide represented by the general formula (IIa) Mn2+(1−a)Al3+a(OH)[2+a−nz](An−)2·mH2O (wherein An− is an anion having a valence n, 0.001≦a≦0.25, 0.03<z<0.3 and 0<m) with a water-soluble lithium compound in a molar ratio of Li/(Mn+Al) of 0.45˜0.55 in an aqueous medium to obtain a slurry, spray- or freeze-drying the obtained slurry, and heating the resultant dry material at a temperature of 600˜900° C.