Abstract: As a ball for ball bearing there is provided a ceramics-coated ball made of a steel having almost the same linear thermal expansion coefficient as that of the bearing ring of the ball bearing and coated with a ceramics material. In this arrangement, even when the temperature during bearing assembly and the working temperature differs from each other, the release of preload or excessive preload can be prevented as in ceramics ball because the bearing and the ball can expand or shrink in the same manner. Further, since the ball and the bearing ring contact with each other via the ceramics layer, fretting abrasion can be prevented, making it possible to obtain excellent running performance and acoustic properties.

Abstract: A ball polishing method includes the steps of rotating one of two plates through use of a rotating mechanism while balls are sandwiched between the plates, pressing one of the two plates against the other plate via a guide slide mechanism for guiding one of the two plates to the other plate by means of a pressing mechanism, and polishing the balls while the pressing force is regulated through use of a pressing force control mechanism. The method is further provided with rotary support means for supporting the rotating mechanism and guide support means for supporting the guide slide mechanism, and at least one of them utilizes hydrostatics. By virtue of this method, a machining pressure can be controlled with a high degree of accuracy, and the accuracy of polishing of balls can be improved.

Abstract: A ball polishing method includes the steps of rotating one of two plates through use of a rotating mechanism while balls are sandwiched between the plates, pressing one of the two plates against the other plate via a guide slide mechanism for guiding one of the two plates to the other plate by means of a pressing mechanism, and polishing the balls while the pressing force is regulated through use of a pressing force control mechanism. The method is further provided with rotary support means for supporting the rotating mechanism and guide support means for supporting the guide slide mechanism, and at least one of them utilizes hydrostatics. By virtue of this method, a machining pressure can be controlled with a high degree of accuracy, and the accuracy of polishing of balls can be improved.

Abstract: A spherical member polishing apparatus has a fixed disk which is disposed in opposition to a rotating disk with a predetermined clearance. The rotating disk is rotated, and spherical members are clamped and pressurized between the rotating disk and the fixed disk for roll-polishing the spherical members. A plurality of grooves are formed along a circumferential direction of the fixed disk, and a plurality of working-fluid supply ports are randomly formed along the circumferential direction between the grooves, between the groove and an outer peripheral portion of the fixed disk, and between the groove and an inner peripheral portion of the fixed disk. The working fluid is supplied through the working-fluid supply ports to the fixed disk. A large number of spherical members are polished at a high precision, while a variation in polishing precision and the like are avoided as much as possible.