| 摘要 |
PURPOSE: To secure a large load capacity while the power consumption is minified during the operation by applying the large magnetic force between the end face in the magnetizing direction of a permanent magnet and a flange, and connecting the end faces on the opposite side to each other by a back yoke. CONSTITUTION: A magnetic bearing unit 28 is provided with a pair of permanent magnets 30a, 30b, a back yoke 31, and a magnetizing coil 32. When a rotary shaft 2 is tilted downward, an auxiliary magnetic circuit is formed in the magnetic bearing unit 28 by energizing the magnetizing coil 32 in the prescribed direction. In this condition, the magnetic attraction based on the auxiliary magnetic circuit is added to the magnetic attraction to be applied between the permanent magnets 30a, 30b and a ferromagnetic steel sheet 25. Thus, the magnetic attraction to be applied between the magnetic bearing unit 28 and the steel sheet 25 is increased to prevent a rotary shaft 2. On the contrary, when the rotary shaft 2 is tilted upward, the magnetic attraction is reduced by energizing the magnetizing coil 32 in the reverse direction to prevent the rotary shaft 2 from being elevated. |
