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 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: Contact surface pressure P increases rather drastically in proportion to skew angle ? within the range of 0<???T, but because the critical skew angle ? is restricted to be small, the contact surface pressure P changes in a low range below a certain level Po at which wear occurs in contact portions. Thus restricting the critical skew angle ?T to a small angle reduces the contact surface pressure P and suppresses heat generation and wear in the contact portions.

Abstract: Contact surface pressure P increases rather drastically in proportion to skew angle ? within the range of 0<???T, but because the critical skew ?T is restricted to be small, the contact surface pressure P changes in a low range below a certain level P0 at which wear occurs in contact portions. Thus restricting the critical skew angle ?T to a small angle reduces the contact surface pressure P and suppresses heat generation and wear in the contact portions.

Abstract: A cylindrical roller bearing suited for higher rotation speeds is provided, which can control heat generation, wearing, and other problems at contact portions between cylindrical rollers and flange portions. A cylindrical roller bearing is composed of an inner ring having a raceway on an outer circumference thereof, an outer ring having a raceway on an inner circumference thereof, a plurality of cylindrical rollers disposed to roll freely between the raceway of the inner ring and the raceway of the outer ring, flange portions formed on both sides of the raceway of the inner ring, and recess grooves formed between flange surfaces of the flange portions on both sides and the raceway. The flange surfaces are inclined at the same angle from a base end portion to a tip end portion thereof. A radial dimension of chamfers of the cylindrical rollers is smaller than a radial height from the raceway near the recess grooves formed in the races.

Abstract: A cylindrical roller bearing suited for higher rotation speeds is provided, which can control heat generation, wearing, and other problems at contact portions between cylindrical rollers and flange portions. A cylindrical roller bearing is composed of an inner ring having a raceway on an outer circumference thereof, an outer ring having a raceway on an inner circumference thereof, a plurality of cylindrical rollers disposed to roll freely between the raceway of the inner ring and the raceway of the outer ring, flange portions formed on both sides of the raceway of the inner ring, and recess grooves formed between flange surfaces of the flange portions on both sides and the raceway. The flange surfaces are inclined at the same angle from a base end portion to a tip end portion thereof. A radial dimension of chamfers of the cylindrical rollers is smaller than a radial height from the raceway near the recess grooves formed in the races.

Abstract: A rolling bearing provided with measures to suppress a rise in temperature. The rolling bearing comprises inner and outer races, a plurality of rolling elements 16 interposed between the inner and outer races, and a cage for retaining the rolling elements 16. On the use conditions that the direction of load is stationary to the outer/inner race and rotational with respect to the inner/outer race of the two races, the cage 17 is guided for rotation with outer/inner regions of its pocket surfaces in contact with the rolling elements 16. It is also intended to facilitate satisfactory lubrication by means of grease and to enhance the durability and life of the bearing. For that purpose, a bearing 21 incorporated into a main motor is arranged with both end faces adjoining end members 24 and 25 that have grease pockets 22 and 23 formed therein, respectively.