| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing for keeping adequately dynamic pressure balance by eliminating differential pressure in an axial direction by means of circulating a lubricating fluid through an air hole inside a bearing member. SOLUTION: Circumferential grooves 21, 22, 23 serving as a fluid circulating means of the lubricating fluid 10 are formed in an area adjacent to a dynamic pressure generating surface 4x, 4x in an inner peripheral surface 4a of a bearing sleeve 4. This structure enables the lubricating fluid 10 to circulate through the air hole inside the bearing sleeve 4 owing to a resultant exposure of a porous portion inside the bearing sleeve 4. Consequently, in this dynamic pressure bearing, even when there exists variation in processing accuracy of a dynamic pressure groove 4v, the differential pressure in the axial direction of a shaft 5 is eliminated, so that leakage of the lubricating fluid 10 into an opening end side, excessive lift of the shaft 5 toward a closed side is prevented. COPYRIGHT: (C)2004,JPO
|
