| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing device for preventing the rotor-height instability of a motor as a result of the worsening of the cylindricity of a sleeve to float a shaft. SOLUTION: The sleeve 2 to which the shaft 1 is fitted has an oil reservoir 5a at the upper end, a first dynamic pressure generating part 6a, a first recessed part 5b, a second dynamic pressure generating part 6b, and a second recessed part 5c. To the lower end of the sleeve 2, a disc 3 is caulked and fixed for closing a bearing hole. When the cylindricity of the sleeve 2 is changed by the caulking of the disc 3, dynamic pressure balance is lost between the dynamic pressure generating parts 6a, 6b to float the shaft 1. Therefore, the diameter size of the second recessed part 5c at the lower end is set smaller than the diameter size of the first recessed part 5b on the upper side to reduce the change of the cylindricity. COPYRIGHT: (C)2008,JPO&INPIT |
