DYNAMIC FLUID BEARING DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To suitably close pores of a surface of a sleeve comprising a porous material such as a green molded metal sintered body. SOLUTION: This dynamic fluid bearing device is provided with the sleeve 3, a shaft 1 inserted into a bearing hole 3A of the sleeve 3 so as to be relatively rotatable, and a dynamic pressure generation groove formed on an inner peripheral surface of the sleeve 3. A ratio of surface pores of the sleeve 3 is 0.01 or less. Further, a triiron tetraoxide (Fe3O4) film having a thickness of 2-10 micrometers is formed on the porous surface. COPYRIGHT: (C)2007,JPO&INPIT