| 摘要 |
PURPOSE:To fit a sealing device in a narrow space easily and with good accuracy by providing two pole pieces, one of which has such a size as to form a void between the pole piece and the first magnetic member when a seal member is fitted. CONSTITUTION:Magnetic flux flowing from a pole piece 12 to a housing H (the first magnetic member) by a magnet 11 is intercepted in a void portion G, so that a high magnetic field is generated between pole pieces 12, 13 and a shaft S (the second magnetic member). Thus, magnetic fluid Z is strongly retained in the void by the high magnetic field, and the proof pressure is increased. Accordingly, a non-magnetic ring which was used in the conventional apparatus is not required. The fitting accuracy of a seal member to the housing H is univocally determined between both members H and S. Even if the space between both members H and S is narrow, the seal member can be fitted between both members with good accuracy. |
