FLUID DYNAMIC PRESSURE BEARING AND LUBRICATION METHOD THERETO

摘要

PROBLEM TO BE SOLVED: To suppress an amount of residual air in a sleeve to be minimum by forming an inner diameter of a lubricant reservoir at the bottom of the sleeve such that a diameter of a horizontal part of an oil level lubricated into the bottom of the sleeve becomes larger than a diameter of a tip of a rotation shaft and by making the tip of the rotation shaft into a tapered shape. SOLUTION: In a fluid dynamic pressure bearing sealed on a thrust receiver 3 side, a bottom of a sleeve 1 is lubricated without adhering oil on a side surface of the sleeve 1. An inner diameter of a lubricant reservoir at the bottom of the sleeve 1 is formed such that a diameter of a horizontal part of an oil level lubricated into the bottom of the sleeve 1 becomes larger than a diameter of a tip of a rotation shaft 2, which is made into a tapered shape. Residual air in the sleeve 1 can be thereby suppressed to be minimum when a rotor and the sleeve 1 are assembled, and elevation of the oil level caused by temperature rise can be suppressed. Durability of the fluid bearing can be also improved.