| 摘要 |
PROBLEM TO BE SOLVED: To propose a dynamic pressure bearing motor which increases the axial rigidity of a shaft and prevent the fluid dynamic pressure bearing section from entering into a lubricant or the like caused by compressed air. SOLUTION: A solid section 48 is formed in the shaft 4 in order to prevent the axial deformation of the shaft 4 caused by press fit of the upper and lower clamp members 7, 8, and an axially penetrating through hole 83 is formed in the lower clamp member 8 and the lower space SP2 is arranged to communicate with the outside air through a ventilation root R4 formed by the penetrating through hole 83, a gap between the head 82 of the lower clamp member 8 a first plate 12, and a gap between the lower end face 33 of a sleeve 3 and the first plate 12, and a venting root R. In this way, the axial rigidity of the shaft is increased and the air in the lower side space SP2 is discharged to the outside air without mixing of the air of the lower side space SP2 with the lubricant 15 of the radial fluid dynamic pressure bearing section HB2.
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