| 摘要 |
PURPOSE:To stabilize holding force of magnetic fluid by locating the side tip portion of a band projecting from the inner circumferential section of a magnet at a position separated farther from the magnet side face of a pole piece than the surface shaft. CONSTITUTION:A magnet 4 has an annular band 8 projecting toward the center of a shaft 1 in the center of inner circumferential section, where the inner diameter face 9 of the projecting band 8 has a cylindrical face parallel with the surface 7 of the shaft 1. The opposite side face 10 of the projecting band 8 are tapered by 45 deg. to the opposite side faces 11 of the magnet 4. Respective tip portions 12 at the opposite side sections of the projecting band are located at a position separated farther from the magnet side face of a pole piece 5 than the surface 7 of the shaft 1. Consequently, double stage magnetic fluid seals can be formed while being separated from each other between the tip portion of the projecting band 8 and the surface of the shaft 1. |
