| 摘要 |
PURPOSE:To eliminate a composite control circuit by detecting the position relationship between the coil of a 3-phase movable coil type linear DC motor and polarity direction of a magnet by three sensors in an absolute type. CONSTITUTION:A code plate 20 is a light shielding type, and light transmission windows are opened in the prescribed pattern. A photodetector 10A has three pairs of photocouplings, which are linearly arranged in widthwise direction of the plate 20 in a photodetector 10, and the light source of the photocouplings and the photosensors are opposed through the plate 20. Six coils secured to a carriage 10 pass a yoke 12. Magnets M1, M2... are fixedly arranged on the yoke 12. The adjacent magnets have reverse polarities. |
