摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.