| 摘要 |
PURPOSE: To obtain a commutation switching device which has higher precision by a method, wherein a transistor is exclusively operated by the magnetic field of a rotor magnet which is the same magnet driving a motor and the magnetic field is concentrated in the direction which pierces through the transistor by core material, provided on the opposite side of the transistor. CONSTITUTION: A Hall transistor 26 is tightly fitted to an annular slot 24 between the center part of a rotor core 22 and a rotor drive magnet 28 attached to the outside of the rotor core and is surrounded by three surfaces on the rotor 28 side. A stator coil 20 is fixed to a motor main part 23 and provided around the rotor with a small gap therebetween. The rotor drive magnet 28 is employed as a commutation magnet and induces a magnetic field more intense than a conventional one. Further, as the part of the rotor core 22 which is placed on the side opposite to the side of a switching transistor is made of ferromagnetic material, a magnetic passage written by magnetic lines of force is concentrated in a direction piercing through the transistor and is in parallel with a switching plane. |
