| 摘要 |
PURPOSE:To effectively affect a magnetic flux fo carrying out an incrementing operation to a scale by interposing a permanent magnet which is magnetized in a direction for disturbing the generation of a leakage magnetic flux of a main magnetic flux between aligned adjacent cores perpendicularly to the moving direction of a slider. CONSTITUTION:A slider 2 is disposed oppositely to a scale 1 provided by displacing by half pitch central teeth 1a and side teeth 1b1, 1b2. The slider 2 is divided at the pole cores 3, 4, 5 in a direction perpendicular to the moving direction of the slider, a magnetic flux by a permanent magnet 8 and a magnetic flux by an electromagnet made of poles 3a-3d, 4a-4d and 5a-5d and coils 10, 11 are added, cancelled, and permanent magnets 6', 7' magnetized in a direction for disturbing the generation of a leakage magnetic flux are interposed between adjacent cores 3, 4 and 4, 5. Accordingly, the reduction in the amount for passing the scale 1 of the main magnetic flux is prevented, the efficiency can be improved, and the nise can be reduced. |
