| 摘要 |
PURPOSE:To enable to use for a high speed rotation state by arranging a plurality of permanent magnets through a doughnut-shaped spacer, coating the entirety with a nonmagnetic metal and throttling it. CONSTITUTION:A plurality of permanent magnets 4 formed in an arcuate shape are arranged on the flat portion of a rotational shaft 1 through a spacer 5 inserted into the shaft 1. The spacer 5 is formed with arcuate-shaped grooves on the periphery of a nonmagnetic material and entirely formed in a doughtnut shape. Resin 7 is buried in an air gap between the spacer 5 and the flat portion of the shaft 1, and a yoke 8 is arranged in the air gap between the magnets 4, 4 and the flat portion of the shaft 1. The rotary pole which is formed as described above is coated with a nonmagnetic metal cylinder 9. Further, the outer periphery of the cylinder 9 is throttled along the groove of the spacer 5. |
