| 摘要 |
PURPOSE:To suppress vibration, noise and rotational fluctuation and to lengthen ON/OFF service life by filling a space, formed by a shaft, a supporting tube and a radial bearing, with a magnetic fluid and fixing a polygon mirror to the upper face of a rotor supporting member. CONSTITUTION:A plurality of oil grooves 23, about half in length of the dimension in thrust direction of a radial bearing 5, are formed and the space, formed by a shaft 15, a supporting tube 7A and the radial bearing 4, is filled with a magnetic fluid 11. A polygon mirror 14 is fixed to the upper face of a rotor supporting member 16 and a cover 17 for the polygon mirror 14 is secured to the housing 3 thus constituting a polygon mirror motor. An integrally sealed magnetic fluid bearing unit is built in a drive coil unit and then the rotor shaft 15 is inserted into the open end of the bearing unit. |
