FLUID DYNAMIC PRESSURE BEARING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a fluid dynamic pressure bearing device suppressing dimension change of an inner circumference surface of a bearing sleeve and having high radial direction bearing force. SOLUTION: Density of a sintered metal bearing sleeve is set in a range of 80-95% of true density and Young's modulus of the bearing sleeve is set to 70 GPa or higher. Dimension change of the inner circumference surface of the bearing sleeve is kept to 0.5 μm or less when a shaft member of 2-4 mm is supported, by not only increasing density of the bearing sleeve but also keeping Young's modulus 70 GPa or higher in such a manner. COPYRIGHT: (C)2011,JPO&INPIT