| 摘要 |
PURPOSE:To facilitate the production and to reduce the man-hour for production to attain a high rotation precision, by forming an air groove for radial load and an air groove for thrust load on a fixed shaft stood on a motor base material to reduce the number of positions where a dynamic pressure air current is formed. CONSTITUTION:When a revolving shaft 11 is rotated, the dynamic pressure air current is formed between the shaft 11 and a fixed shaft 3 by an air groove 4 for radial load and an air groove 5 for thrust load, and air is flowed into the space between the revolving shaft 11 and the fixed shaft 3 from the base end side of the fixed shaft 3 as shown by arrows in Fig. and is flowed out from an air hole 12 of cock body 13. At this time, an air pressure is generated between the fixed shaft 3 and the revolving shaft 11 by the dynamic pressure air current, and therefore, an air pressure acting essentially in the radial direction is generated in the part of the air groove 4 for radial load, and an air pressure acting essentially in the thrust direction and acting in the radial direction also is generated in the part of the air groove 5 for thrust load. Thus, high-precision works are unnecessary for the lower end face of the revolving shaft and the motor base material to facilitate the production, and the rotation precision is improved because an optical deflecting mirror body and a rotor are supported near the position where maximum air of the dynamic pressure air current is generated. |
