| 摘要 |
PURPOSE:To prevent demagnetization in a magnet, by forming at least one one magnet multipole-magnetized at all-round saturation, in a tubular shaft direction of a pole piece. CONSTITUTION:A multipolar magnet 70 is a permanent magnet formed into round tubular form to a shaft rod 1 and magnetizing four poles of N, S and N, S in the axial direction, and a magnetic fluid 5 is held between the multipolar magnet 70 and the shaft rod 1. A line of magnetic force of the multipolar magnet 70 flows as shown in 81-83, and since the magnetic fluid 5 is held between the shaft rod 1 and a magnetic pole part where the multipolar magnet is magnetized, a seal between the shaft rod and the multipolar magnet can be done. Therefore, the whole magnetic flux holdable by a magnetic material is increased and, what is more, a drop in coercive force is also prevented from occurring. |
