| 摘要 |
PURPOSE:To obtain the excellent rotating accuracy and smaller thickness of the rotary polyhedral mirror driving device to be used for an LBP at a low cost by solving the degradation in the rotating accuracy of the device and the accuracy of a bearings. CONSTITUTION:A rotor boss 5 to be fixed with a rotary polyhedral mirror 2, a rotor magnet 3 and a rotor yoke 4 is fixed to a revolving shaft 1 by a method, such as shrinkage fitting, by which a rotor 13 is constituted. A bracket 16 is constituted of a liquid crystal display material base 11 which constitutes a magnetic path with the rotor magnet 3 and a resin collar 15 outsert molded to this base plate 11. The revolving shaft 1 is supported rotatably by the bearing 10, by which the absolute plane tilt is assured in spite of the presence of warpage in the base plate 11 as the collar 15 is molded on the basis of such warpage. The rigidity of the resin collar 15 is made lower than the rigidity of the metallic sleeve and the coefft. of linear expansion is approximated to the coefft. of linear expansion of the sleeve, by which the driving device is assembled and maintained with substantially no change in the bore accuracy of the sleeve. The effect thereof is particularly high if the change in the bore of the fluid bearing, etc., significantly affects the loss and rigidity of the sleeve. |
