Abstract: There is prepared a formed body constituted of steel and having an outer circumferential surface having an annular groove having a bottom surface to serve as a raceway surface of the bearing ring. In the step of forming a heated region, the formed body is induction heated to form a heated region including the bottom surface of the groove and heated to a temperature of at least an A1 point. In the cooling step, the whole of the heated region is simultaneously cooled to a temperature of not more than an Ms point. The step of retaining the formed body in a state in which heating is stopped is performed after the step of forming a heated region before the step of cooling. In the step of retaining, dispersion in temperature in the heated region in the circumferential direction is suppressed to not more than 20° C.

Abstract: A double row tapered roller bearing includes: an outer ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and having an annular shape; and rollers. The inner ring has an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface. The rollers are tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and are also in contact with the outer ring. At outer circumferential surface of the inner ring, a region adjacent to the groove includes a hardened region extending from the inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region.

Abstract: A heat treatment method includes the steps of: measuring a hot section temperature; measuring a cold section temperature; adjusting a temperature of a workpiece; and determining quenching timing for the workpiece. The step of adjusting a temperature includes the steps of: heating the workpiece by high energy heating; and controlling heating based on the hot section temperature. In the step of determining quenching timing, the quenching timing is determined based on the hot section temperature and the cold section temperature so as to achieve a predetermined solid-dissolved state of carbon on a TTA diagram in the entire workpiece. The TTA diagram is derived by a calculation formula obtained by conducting a regression analysis of a result of an experiment performed for examining a relation between the solid-dissolved state of carbon and each of a heating temperature and a heating time of steel.

Abstract: A double row tapered roller bearing includes: an outer ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and having an annular shape; and rollers. The inner ring has an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface. The rollers are tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and are also in contact with the outer ring. At outer circumferential surface of the inner ring, a region adjacent to the groove includes a hardened region extending from the inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region.

Abstract: There is prepared a formed body constituted of steel and having an outer circumferential surface having an annular groove having a bottom surface to serve as a raceway surface of the bearing ring. In the step of forming a heated region, the formed body is induction heated to form a heated region including the bottom surface of the groove and heated to a temperature of at least an A1 point. In the cooling step, the whole of the heated region is simultaneously cooled to a temperature of not more than an Ms point. The step of retaining the formed body in a state in which heating is stopped is performed after the step of forming a heated region before the step of cooling. In the step of retaining, dispersion in temperature in the heated region in the circumferential direction is suppressed to not more than 20° C.

Abstract: A method for producing a bearing ring of a double row tapered roller bearing includes the steps of: preparing a formed body; forming a heated region; cooing; and removing. In the step of forming a heated region, an induction heating coil arranged to face part of the groove and induction-heating the fixated body is relatively rotated along the circumferential direction of the groove to form a heated region including the bottom surface of the groove and heated to a temperature of at least an Al point. In the cooling step, the whole of the heated region is simultaneously cooled to a temperature of not more than an Ms point. After the step of forming a heated region before the step of cooling, the method further includes the step of retaining the formed body in a state where heating is stopped.

Abstract: An inspection method for a bearing part includes the steps of: emitting X-rays onto a fatigued portion of a bearing part to be inspected; detecting annular diffracted X-rays (X-ray diffraction ring) diffracted by the fatigued portion; and estimating a use condition of the bearing part to be inspected, based on the detected annular diffracted X-rays (X-ray diffraction ring).

Abstract: A method of manufacturing a machine component includes the steps of: preparing a member made of steel; forming a film containing vanadium at a surface by subjecting the member to oxidation; and forming a nitrogen-enriched layer by heating the member having the film formed in a heat treatment gas atmosphere containing nitrogen gas and absent of ammonia gas for carbonitriding.

Abstract: A method for producing a bearing ring of a rolling bearing includes the steps of: preparing a formed body constituted of hypereutectoid steel; forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region; and simultaneously cooling the whole of the heated region to a temperature of not more than an Ms point.

Abstract: Disclosed is a method for heat-treating a ring-shaped member, which makes it possible to form a quench-hardened region having a uniform annular shape in the circumferential direction, while the production costs in terms of the quenching apparatus are kept down. The method includes the following steps: a step in which a coil which is disposed in such a way as to face a rolling contact surface of a ring-shaped formed body made of steel and which performs induction heating of the formed body is rotated relative to the formed body in the circumferential direction thereof, whereby an annular heating region which is heated to a temperature at or above an A1 point is formed on the formed body; and a step in which the whole of the heating region is simultaneously cooled to a temperature at or below an MS point.

Abstract: A method for producing a bearing ring of a rolling bearing includes the steps of: preparing a formed body constituted of hypereutectoid steel; forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region; and simultaneously cooling the whole of the heated region to a temperature of not more than an Ms point.

Abstract: A heat treatment method includes the steps of: measuring a hot section temperature; measuring a cold section temperature; adjusting a temperature of a workpiece; and determining quenching timing for the workpiece. The step of adjusting a temperature includes the steps of: heating the workpiece by high energy heating; and controlling heating based on the hot section temperature. In the step of determining quenching timing, the quenching timing is determined based on the hot section temperature and the cold section temperature so as to achieve a predetermined solid-dissolved state of carbon on a TTA diagram in the entire workpiece. The TTA diagram is derived by a calculation formula obtained by conducting a regression analysis of a result of an experiment performed for examining a relation between the solid-dissolved state of carbon and each of a heating temperature and a heating time of steel.

Abstract: A present invention provides a method for evaluating pluripotent stem cells comprising: analyzing expression of a clock gene in cells differentiated from a pluripotent stem cell, and evaluating the pluripotent stem cells based on the degree of the expression.

Abstract: A method of manufacturing a machine component includes the steps of preparing a member made of steel containing 0.1 mass % or more of vanadium, forming a film containing vanadium at a surface of the member, and forming a nitrogen-enriched layer by heating the member having the film formed in a heat treatment gas atmosphere containing nitrogen gas and absent of ammonia gas. In the step of forming a film, the member is heated to and oxidized in a temperature range not lower than 500° C. and lower than A1 transformation point of steel.

Abstract: An inspection method for a bearing part includes the steps of: emitting X-rays onto a fatigued portion of a bearing part to be inspected; detecting annular diffracted X-rays (X-ray diffraction ring) diffracted by the fatigued portion; and estimating a use condition of the bearing part to be inspected, based on the detected annular diffracted X-rays (X-ray diffraction ring).

Abstract: A method of manufacturing a machine component includes the steps of: preparing a member made of steel; forming a film containing vanadium at a surface by subjecting the member to oxidation; and forming a nitrogen-enriched layer by heating the member having the film formed in a heat treatment gas atmosphere containing nitrogen gas and absent of ammonia gas for carbonitriding.

Abstract: A method for producing a bearing ring of a rolling bearing includes the steps of: preparing a formed body constituted of hypereutectoid steel; forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region; and simultaneously cooling the whole of the heated region to a temperature of not more than an Ms point.

Abstract: An outer ring and an inner ring of a rolling bearing are constituted of steel containing 0.77 to 0.85% of carbon, 0.01 to 0.25% of silicon, 0.01 to 0.35% of manganese, 0.01 to 0.15% of nickel, 3.75 to 4.25% of chromium, 4 to 4.5% of molybdenum and 0.9 to 1.1% of vanadium with the rest consisting of iron and impurities, a nitrogen-enriched layer having a nitrogen concentration of at least 0.05 mass % is formed on a region including a rolling surface, and the total of a carbon concentration and the nitrogen concentration in the nitrogen-enriched layer is at least 0.82 mass % and not more than 1.9 mass %. A DLC coating layer is arranged on a region including an outer ring contact surface.

Abstract: An outer ring, an inner ring and a ball serving as mechanical components configuring a deep groove ball bearing are formed of steel containing at least 0.11 mass % and not more than 0.15 mass % of carbon, at least 0.1 mass % and not more than 0.25 mass % of silicon, at least 0.15 mass % and not more than 0.35 mass % of manganese, at least 3.2 mass % and not more than 3.6 mass % of nickel, at least 4 mass % and not more than 4.25 mass % of chromium, at least 4 mass % and not more than 4.5 mass % of molybdenum and at least 1.13 mass % and not more than 1.33 mass % of vanadium with a remainder consisting of iron and impurity, and have raceway/rolling contact surfaces, the surface being included in a region having a nitrogen enriched layer having a nitrogen concentration of at least 0.05 mass %, the nitrogen enriched layer having a carbon concentration and the nitrogen concentration, in total, of at least 0.55 mass % and not more than 1.9 mass % at a depth of 0.1 mm from the surface.

Abstract: An outer ring, an inner ring and a ball serving as mechanical components configuring a deep groove ball bearing are formed of steel containing at least 0.77 mass % and not more than 0.85 mass % of carbon, at least 0.01 mass % and not more than 0.25 mass % of silicon, at least 0.01 mass % and not more than 0.35 mass % of manganese, at least 0.01 mass % and not more than 0.15 mass % of nickel, at least 3.75 mass % and not more than 4.25 mass % of chromium, at least 4 mass % and not more than 4.5 mass % of molybdenum and at least 0.9 mass % and not more than 1.1 mass % of vanadium with a remainder consisting of iron and impurity, and have raceway/rolling contact surfaces, the surface being included in a region having a nitrogen enriched layer having a nitrogen concentration of at least 0.05 mass %, the nitrogen enriched layer having a carbon concentration and the nitrogen concentration, in total, of at least 0.82 mass % and not more than 1.9 mass %.