| 摘要 |
PURPOSE:To ensure pressure resistance at seal, to reduce the size and the cost and to improve the reliability by integrally constructing the magnetic circuit for rotary driving a rotor and a magnetic circuit for holding the magnetic fluid through a rotor magnet and integrally constructing the upper and lower covers of yoke and rotor with a seal yoke. CONSTITUTION:Magnetic circuits for rotary driving a rotor 24 and for holding the magnetic fluid 46 are integrally constructed with a rotor magnet 42, while a yoke for holding the magnetic fluid 46 and the upper/lower covers for the rotor 24 are constructed integrally with a seal yoke 43. By such arrangement, the magnetic fluid 46 placed between the seal yoke 43 and a shaft 21 is held by the magnetic circuit constructed with the rotor magnet 42. Consequently, pressure resistance at seal, after injection of the magnetic fluid 46, is improved, the size and the cost are reduced and the reliability is improved. |
