| 摘要 |
PURPOSE:To seal a magnetic disc device by fixing a permanent magnet on a base so that both poles are opposed with an interval, and attracting magnetic fluid by magnetic flux generated between both poles of the permanent magnet to seal an assembling body cover and the base with said fluid. CONSTITUTION:The permanent magnet 13 having a U-shaped section is embetted and fixed by a bonding agent or the like. As to the polarity of the permanent magnet 13, the N and S poles are opposed as shown in the figure. The magnetic fluid 14 is injected into a gap between both magnetic poles of the permanent magnet 13. In this case, the magnetic fluid 14 is colloid solution obtained by dispersing ferromagnetic fine particles such as magnetite stably into water or an organic solvent and has a property to be held in a part having strong magnetic flux, so that the magnetic fluid 14 does not flow out from a part near the gap between both magnetic poles of the permanent magnet 13. Thus, a high sealing structure enabled to seal also inert gas such as helium gas sufficiently can be formed. |
