| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an inexpensive structure having high impedance, which has a structure wherein a ceramic insulating film 4b is formed on a raceway ring. <P>SOLUTION: The ceramic insulating film 4b mainly composed of alumina is formed on the inner circumferential surface 14 of an inner ring 3 and both axial end faces 15, 15. An interference between the inner ring 3 and a shaft is regulated so that a damage is not generated on the insulating film 4b. Since the total surface area of the inner circumferential surface 14 of the inner ring 3 and both end faces 15, 15 is smaller than the total surface area of the outer circumferential surface 12 of an outer ring 2 and axial direction both end faces 13, 13, the impedance can be heightened inexpensively without thickening the film thickness of the insulating coating 4b. <P>COPYRIGHT: (C)2008,JPO&INPIT |
