To improve heat radiating efficiency and control drop of driving force due to increase of pneumatic resistance, by providing a cooling fin curved to the lower direction through erection at the position not opposed to a stator on the surface facing to a rotor of the stator.
A rotor 4 is mounted to a held frame 1 and a stator is provided to a guide frame. The N, S poles of a permanent magnet are alternately provided in the vertical direction to a rotor 4. The stators are provided to a guide frame sandwiching the rotor 4 and two sheets of stators are coiled to iron cores in the same structure. The rotor 4 and stator are provided face to face through a narrow gap, and a magnetic circuit is formed between the rotor 4 and stator. The curved cooling fin 6 provided to the rotor 4 can be mounted to erect at the position not opposing to the stator on the surface facing to the rotor 4 of the stator. Since the cooling fin 6 is curved in the lower side, when the rotor 4 rises inversely, it can rise without receiving strong pneumatic resistance. As a result, the increase of driving force may be eliminated and unnecessary load of motor can also be avoided.
HAYASHI HIROTO
YOSHIDA TOSHIHIKO
