| 摘要 |
PURPOSE:To improve the thrust bearing rigidity of a driving motor and to enhance the height position accuracy of a revolving sleeve. CONSTITUTION:A second permanent magnet 31 is mounted at the bottom end of the revolving sleeve 23 of the driving motor mounted with a rotary polyhedral mirror 13 and a first permanent magnet 30 is mounted at the lower part of a stationary shaft 22 in a direction where this permanent magnet repulses from the permanent magnet 31. Further, a third permanent magnet 32 which acts to press the second permanent magnet 31 to the first permanent magnet 30 by its repulsive force is mounted at a housing 21. The third permanent magnet 32 presses the second permanent magnet 31 toward the first permanent magnet and, therefore, the repulsive force in the thrust direction is intensified and the thrust bearing rigidity is improved. |
