Abstract: A method of manufacturing steel balls for use in a ball bearing comprising an inner steel race or shaft with an inner raceway formed around its outer peripheral surface, an outer steel race with an outer raceway formed around its inner peripheral surface, and the steel balls freely rotatably disposed between the inner raceway and the outer raceway comprises the steps of providing steel balls, quenching the steel balls, preliminarily tempering the steel balls after quenched, rough-polishing the steel balls after preliminarily tempered, surface-hardening the steel balls after rough-polished, tempering the steel balls after surface-hardened, and finish-polishing the steel balls after tempered.

Abstract: To provide a ball bearing that insures reasonable endurance and which reduces the necessary torque for rotation while causing less fluctuations in torque, a synthetic resin cage of the ball bearing for retaining a plurality of balls so as to roll freely is impregnated with a lubricating oil having a viscosity of 10 to 150 mm.sup.2 /s at 40.degree. C. in an amount of 0.1 to 1.0% by weight of the cage, a film of the lubricating oil is formed in a thickness of 0.03 to 20 .mu.m on the surfaces of an inner race, an outer race, balls and the cage, and the amounts of the oiliness agent and the rust inhibitor that are to be contained in the lubricating oils are limited to the specified ranges.

Abstract: A method of manufacturing steel balls for use in a ball bearing comprising an inner steel race or shaft with an inner raceway formed around its outer peripheral surface, an outer steel race with an outer raceway formed around its inner peripheral surface, and the steel balls freely rotatably disposed between the inner raceway and the outer raceway comprises the steps of providing steel balls, quenching the steel balls, preliminarily tempering the steel balls after quenched, rough-polishing the steel balls after preliminarily tempered, surface-hardening the steel balls after rough-polished, tempering the steel balls after surface-hardened, and finish-polishing the steel balls after tempered.

Abstract: To provide a ball bearing that insures reasonable endurance and which reduces the necessary torque for rotation while causing less fluctuations in torque, a synthetic resin cage of the ball bearing for retaining a plurality of balls so as to roll freely is impregnated with a lubricating oil having a viscosity of 10 to 150 mm.sup.2 /s at 40.degree. C. in an amount of 0.1 to 1.0% by weight of the cage, a film of the lubricating oil is formed in a thickness of 0.03 to 20 .mu.m on the surfaces of an inner race, an outer race, balls and the cage, and the amounts of the oiliness agent and the rust inhibitor that are to be contained in the lubricating oils are limited to the specified ranges.