| 摘要 |
PURPOSE:To accurately construct a high speed motor with low noise by providing at least two magnetic field detecting Hall elements and at least one rotation detecting Hall element at the positions corresponding to magnets which are mounted on a rotational shaft. CONSTITUTION:A rotational shaft 12 of a motor 7 is held rotatably at the bearings 11, 11' of end brackets 9, 10 at both sides of a casing 8. The bearing 11' is supported by a spring 16 in a cylinder 15, and the bearing 11 is supported by a bearing holder 13 which is retained by a leaf spring 14. A permanent magnet 17 is mounted around the shaft 12, and a stator 19 is mounted on the casing 8 corresponding to the magnet 17. At least three holders 20 are mounted on the bracket 10, and a Hall element 21 is mounted at the end. A magnetic field is detected by two Hall elements 21, the coil 18 of the stator 19 is equentially energized to rotate the magnet 17, and the rotation of the magnet 17 is detected by one Hall element 21. High speed can accurately be performed with low noise. This is adapted for scanning a beam of a laser beam printer. |
