| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic pressure generating device which can suppress deterioration in bearing performance caused by the occurrence of contamination as much as possible. SOLUTION: A dynamic pressure generating part A is disposed on a radial bearing face out of the inner peripheral face 8a of a sleeve 8 as a porous member. The dynamic pressure generating part A comprises: a first inclined groove group A1 constituted of a plurality of first inclined grooves A11 arranged in a circumferential direction; and a second inclined groove group A2 constituted of a plurality of second inclined grooves A21 different in inclination direction from the first inclined grooves A11 and arranged in the circumferential direction. In the first inclined groove group A1 of the dynamic pressure generating part A, a hill A12 is formed between the first inclined grooves A11, A11 adjacent to each other in the circumferential direction. In the second inclined groove group A2, a hill A22 is formed between the adjacent second inclined grooves A21, A21. A smooth surface A3 is formed between the first inclined groove group A1 and the second inclined groove group A2 around the whole circumference of the inner peripheral face 8a. Here, a surface opening hole ratio of the inner peripheral face 8a is maximized at a smooth surface A3. COPYRIGHT: (C)2008,JPO&INPIT
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