| 摘要 |
PROBLEM TO BE SOLVED: To effectively suppress the unstable vibration such as the whirling without minimizing the bearing gap by arranging three grooves for generating the dynamic pressure on the circumference with equal intervals, and setting the ratio of the circumferential length of the grooves to the circumferential length of a hill part in the prescribed range. SOLUTION: The ratio Ag:Ar is set in a range of 1:1 to 1:2, andα=Ag/Ar=1-2, where Ag is the circumferential length of grooves 2 for generating the dynamic pressure, and Ar is the circumferential length of a hill part 3 between grooves 2 adjacent to each other in the circumferential direction for generating the dynamic pressure. In a case where M=0.5 with a bearing of continuous groove type, the stable limit bearing numberΛbecomes maximum when the number of the grooves (the number of the grooves for generating the dynamic pressure) N=3, and the stable limit bearing numberΛbecomes smaller whether the number N of the grooves is smaller or larger than 3. The unstable vibration such as the whiling can be effectively suppressed in an area of the practical number of revolution even when the bearing gap 4 is not specially small.
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