| 摘要 |
PURPOSE:To prevent the leakage of dynamic pressure generated in a bearing with high air pressure generated in a cover member and to the reinforce the function of a dynamic pressure bearing by covering a rotation part with the cover member of a specified structure. CONSTITUTION:The rotation part 1 is covered by the cover member 10 which is fixed to a fixed part 4 and whose section inner size in the direction of a rotary shaft becomes gradually smaller with the distance from the fixed part 4. The cover member 10 is provided with an opening hole 11 of a circular shape on the end surface in the direction of the rotary shaft 3. At the time of rotation, air in the vicinity of the upper surface of the rotation part 1 entering from the open hole 11 to the cover member 10 is moved in the radial direction of the rotation part 1 by centrifugal force by the rotation of the rotation part 1. Then, the moved air is led in the direction of the fixed part 4, that is, downward the rotation part 1 by the tapered surface of the cover member 10. The air flow compresses the air of the lower part of the rotation part 1 to increase air pressure of the part, and since the vicinity of the rotary shaft 3 joint part of the rotation part 1 lower surface is held to the high air pressure generated in the cover member 10, the dynamic pressure is held higher without leaking the dynamic pressure generated in the bearing 6. |
