| 摘要 |
PROBLEM TO BE SOLVED: To secure the stabilized bearing rigidity while preventing the run out of the lubricating oil by forming parts having a large bearing clearance between adjacent hydrodynamic pressure generating groove patterns so as to be adjacent to them and a part having a small bearing clearance between the described parts having a large bearing clearance. SOLUTION: Hydrodynamic pressure generating groove patterns 4, 5 of a herringbone groove are formed in radial bearing surfaces 2, 3 in the inner diameter surface of a bearing sleeve 1 at plural positions in the axial direction, and parts 16, 18 having a large bearing clearance are arranged between adjacent groove patterns 4, 5 so as to be adjacent to them, and a small bearing clearance part 17 is arranged between the parts 16, 18. At the time of rotating a bearing shaft 6, the lubricating oil is securely held in the small bearing clearance part 17 by the surface tensile force so as to prevent the generation of even flow in the axial direction. Furthermore, the parts 16, 18 having a large bearing clearance work as a large lubricating oil tank so as to prevent the generation of run out of the lubricating oil of the radial bearing surfaces 2, 3. Stabilized bearing rigidity is thereby secured, and durability to the rotation for a long time is improved.
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