| 摘要 |
PURPOSE:To effectively prevent the leakage magnetic flux of the end face of a magnetic flux by determining a gap between the end of a supporting shaft side of a permanent magnet and a center yoke and the end of a side yoke in the prescribed range. CONSTITUTION:The end 5b of a permanent magnet 5, the end 4b of a center yoke 4 and the end 5'b of a permanent magnet 5' respectively coincide with the end 3b of a side yoke 3 and the end 3'b of a side yoke 3' at the opposite side of a supporting shaft 7, i.e., at the opposite side to a magnetic disc. Gaps between the ends 5a, 5'a, 4a of the permanent magnets 5, 5' and the supporting shaft 7 side of the center yoke 4 and the end 3a of the side yoke 3 is set to a range of 0.3-0.7 times of the thickness of the magnets 5, 5'. |
