| 摘要 |
PURPOSE:To reasonably contain a detecting mechanism for rotational speed and miniaturize it at a low cost, by providing an encoder consisting of concentric magnetic tracks magnetized in 2<n> poles, on the counter stator side face of a magnet rotor, and by making the encoder confront sensors. CONSTITUTION:Armature coils 13 are arranged on a printed board 11 to form a stator armature 12, and the armature 12 and a magnet rotor 6 are confronted together face to face. The magnet rotor 6, fixing a plastic magnet 15 magnetized in 2P poles on the side face confronting the stator armature 12 on a rotor yoke 7, is provided with a magnetic encoder face 17 on the counter side face to be formed. The magnetic encoder face 17 is formed with concentric magnetic tracks magnetized in 2<n>(2, 4, 8...) poles in order, and is made to confront a plurality of magnetic sensors 10 provided on the fixed side, thus forming a magnetic encoder. |
