| 摘要 |
PURPOSE: To reduce magnetic hindrance from armature coils and to lessen malfunctions by shielding the coil parts of the armature being in the vicinity of a magnetic detecting means with a magnetic shielding means. CONSTITUTION: In a motor, a stator is constituted by winding coils 10 on a core 1 fixed to a flange 4 and an end cap so as to be opposed to permanent magnets 3 provided on a rotor, and a Hall sensor 5 is fitted on to a circuit board 50 put inside the end cap. A magnetic field generated by the coils 10 runs between the magnetic radiating surface of the core 1 and the permanent magnets 3 concentratedly, but outgoing leakage magnetism on the side of the Hall sensor 5 out of magnetic lines of force going out aside, is concentrated in a magnetic shield and does not leak outside, since the magnetic shield 2 forms a magnetic circuit. As the result, the Hall sensor can sense only the change of the ever-changing magnetic poles of the permanent magnets purely. And it becomes possible to prevent malfunctioning, and it raises the rotation efficiency sharply. |
