| 摘要 |
PURPOSE:To improve the dust seal performance while to prevent dispersion of magnetic fluid by bevelling the facing section against the rotary body or a gap section for injecting magnetic fluid of pole piece. CONSTITUTION:A magnet 22 is held by two ring boards of upper and lower pole pieces 21-a, 21-b to inject magnetic fluid 24 into a gap against a soft magnetic rotary body 23. The gap side innercircumference of pole pieces 21-a, 21-b are bevelled such that magnetic field gradient is provided in the gap for holding magnetic fluid such that the magnetic field will be stronger toward the dust- proof space. Consequently, dust-proof performance against non-magnetic dust having low specific gravity is improved resulting in prevention of disperse of magnetic fluid to the dust-proof space side. |
