| 摘要 |
PURPOSE: To provide a multistage magnetic fluid shaft sealing device by which particles are not generated to the vacuum environment. CONSTITUTION: In a multistage magnetic fluid shaft sealing device provided with a rotary shaft l, a plurality of pole pieces 41 radially and axially provided on the periphery through fine clearances, a plurality of ring-like protrusions 11 provided on the outer periphery of the rotary shaft and on the inner periphery of the pole pieces, a permanent magnet 5 fixed by being pinched between the pole pieces, and magnetic fluid 6 filled in the fine clearances so as to face the protrusions, the space between the first magnetic fluid and the second magnetic fluid from the vacuum side to the atmospheric side is communicated to the vacuum side by a communication hole 7. The communication hole 7 is provided on the pole piece, and it is more preferable that sintered metal is used for the pole piece. Moreover, a communication hole in which sintered metal or plastic fiber is filled may be formed on the rotary shaft side. |
