| 摘要 |
PURPOSE:To prevent the scattering of a magnetic fluid in a magnetic fluid seal by providing the magnetic fluid seal on an fixed side never rotating, so that the magnetic seal is never rotated even if a hub is rotated. CONSTITUTION:Receiving members 16, 16 consisting of magnetic material are fixed to a hub 6, and magnetic fluid seals 17, 17 are provided on a base plate 1 and a top cover 2. The receiving member 16 is formed of a cylindrical body part 16a whose inner circumferential surface 20 is close to the outer circumferential surface 4c of a shaft 4 and a large diameter part 16b continuously provided from the base end part of the body part 16a. The large diameter part 16b of one receiving member 16 is fixed to the inner circumferential surface of the spacer 6b of the hub 6, and that of the other receiving member 16 to the inner circumferential surface of the thick part 21 of the body part 6a of the hub 6. The magnetic fluid seal 17 is formed of a ring magnet 24, a pair of pole pieces 25, 25 nipping the magnet, and a magnetic fluid 19 charged between the inner circumferential surfaces of the pole pieces 25, 25 and the outer circumferential surface 18 of the receiving member 16. Thus, the magnetic fluid 19 becomes difficult to scatter. |
