| 摘要 |
PURPOSE:To make the titled polygon mirror small in size and light in weight by forming a dynamic pressure air bearing by a mirror surface of a polygon mirror and a wall surface which is placed so as to be opposed to said surface. CONSTITUTION:A shaft 1 is pressed into a housing 2 and fixed, and a coil 4 for generating a rotating magnetic field is provided on the shaft 1. In the periphery of its coil, a polygon mirror 3 whose inner wall surface is magnetized, and which forms a rotor of a motor is provided. A window 6 is a window for allowing a laser to go in and out. By a mirror surface 3A of the polygon mirror, which is rounded a corner formed by the mirror surface and the mirror surface, and a housing inner wall surface 2A which is placed so as to be opposed to said surface, a dynamic pressure air bearing is formed and a load in the radial direction is received, and on the bottom part of the polygon mirror, a groove for generating a dynamic pressure is provided, forms a dynamic pressure air bearing with a housing inner wall surface 2B and receives a load in the thrust direction. In such a way, since the bearing is formed by utilizing the polygon mirror, the titled polygon motor can be made small in size and light in weight. |
