| 摘要 |
PURPOSE:To prevent electrolytic corrosion of steel balls of a bearing and to reliably perform earthing the rollable steel balls by use of an attracting force of a magnet and making a shaft and a borne member, between which a relative rotation is generated, in a conductive state at all times. CONSTITUTION:Steel balls 63 are attracted by an attracting force F of a permanent magnet 62 and always in contact with an internal surface 51a of a motor frame 51 by a horizontal component F1 and with a conducting plate 61 by a vertical component F2. Thus, the conducting plate 61 and the motor frame 51 is made in a conductive state. Since the steel balls 63 roll while the steel balls hold themselves in contact even when the conductive plate 61 is rotated with a shaft 54, the conductive state is held independent of the rotational speed of the shaft 54. Accordingly, static electricity, generated by the rotation of a magnetic disk, is earthed through a hub, the shaft 54, the conducting plate 61, the steel balls 63, the motor frame 51 and an earthing wire. |
