| 摘要 |
PURPOSE:To reduce incidence of fault by arranging magnetic fluid sealing mechanisms at the outside of a motor and arranging a larger number of motor components at the inside. CONSTITUTION:A spindle motor 1 comprises a rotor, a stator and bearings 9a, 9b. The rotor is provided with a rotor magnet 2, a magnetic rotor yoke 3 arranged at the outer circumferential side and a shaft 4, while the stator is provided with an armature coil 5 arranged at the inner circumferential side of the rotor magnet 2 through a gap, a magnetic back yoke 6 and a base member 8. In order to provide a narrow gap with respect to the outer circumferential face of the rotor yoke 3, an annular magnetic fluid sealing member 7 is fixed to the base member 8 and magnetic fluid 10 is injected into the gap between the rotor yoke 3 and a magnetic fluid sealing member 7. By such arrangement, flux of the rotor magnet 2 penetrates through the armature coil 5 then passes through the back yoke 6 and penetrates through the coil 5 again. |
