CERAMIC DYNAMIC PRESSURE BEARING, MOTOR WITH BEARING, HARD DISK DEVICE, AND POLYGON SCANNER

摘要

PROBLEM TO BE SOLVED: To provide a ceramic dynamic pressure bearing capable of preventing the occurrence of wear when starting and stopping. SOLUTION: An electrode 30 for floating on a second member side and an electrode 40 for floating on a thrust plate side are formed on a thrust dynamic pressure clearance formation face M5 on a bearing part 15 (second member) side and on a thrust dynamic pressure clearance formation face M6 on a thrust plate 23 side, respectively. It is possible to let a static electricity repellent force act by the application of a voltage by external power supply and float a bearing part 15 above a thrust plate 23 between the electrode 30 for floating on the second member side and the electrode 40 for floating on the thrust plate side. Consequently, the bearing part 15 can be kept in a floating condition by a static electricity repellent force even if a thrust dynamic pressure generated in a thrust dynamic pressure clearance 18 is insufficient when rotating at a low speed such as the time of start and stop.