| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing and its manufacturing method causing little damage of dynamic pressure grooves even if a shaft is put in whirling operation of a conical mode, simplifying alignment accuracy for maintaining symmetry in performing electrolytic etching work and exhibiting high performance as the dynamic pressure bearing. SOLUTION: When the inner peripheral surface 1b of a sleeve 1 is provided with a stepped part 1a to form radial dynamic pressure grooves 3 on the stepped part inner peripheral surface, the axial width L of the dynamic pressure grooves 3 is formed to be slightly smaller than the axial width D of the stepped part. The dynamic pressure grooves 3 of the sleeve 1 are formed by electrolytic etching work. In a method of manufacturing the dynamic pressure bearing, resist is formed on a dynamic pressure groove forming surface, at a portion excluding the dynamic pressure grooves having an axial width L smaller than the axial width D of the dynamic pressure groove forming surface, and at both axial ends of the dynamic pressure grooves, and the dynamic pressure grooves are formed by electrolytic etching. COPYRIGHT: (C)2007,JPO&INPIT
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