LIQUID DYNAMIC PRESSURE BEARING UNIT

摘要

PROBLEM TO BE SOLVED: To prevent a solid contact of a rotation side member and a fixed side member at the time of high speed rotation and a deterioration of a dimension accuracy of a rotation shaft by permitting to support a high speed rotation of the rotation shaft and permitting to cool a lubricant by a simple constitution while a small amount of lubricant is circulated without leaking it around the rotation shaft in the case where a liquid is used as a lubricant fluid. SOLUTION: A gas/liquid mixing chamber 44 in which a lubricant pressurized at a bearing space of a dynamic pressure bearing is directly discharged is provided. A liquid feeding means for recovering the lubricant from the gas/liquid mixing chamber 44 and re-supplying the lubricant to the bearing space is provided. The lubricant is cooled by making the lubricant to a fine mist and spraying from the bearing space to the gas/liquid mixing chamber 44. Whereas a temperature rising of the dynamic pressure bearing, i.e., the rotation shaft 21 caused by a shearing friction heat is prevented by re-supplying the lubricant cooled to the bearing space.