FLUID DYNAMIC BEARING DEVICE

摘要

A density of a bearing sleeve made of a sintered metal is set within a range of from 80% to 95% with respect to a true density, and a Young's modulus of the bearing sleeve is set to be equal to or more than 70 GPa. When the density of the bearing sleeve is increased and also the Young's modulus thereof is set to be equal to or more than 70 GPa in this manner, dimensional variation of an inner peripheral surface of the bearing sleeve can be suppressed to be equal to or less than 0.5 μm when a shaft member having an outer diameter of from 2 mm to 4 mm is to be supported.