| 摘要 |
PURPOSE:To simplify the structure of a brushless motor and improve the workability of assembling work, by detecting both of the rotating speed and the rotating position of a rotor by a frequency signal. CONSTITUTION:A bearing housing 2 is fitted to the center of a print wiring substrate 1 used as a stator yoke, and a 3-phase coil 3 is fixed to the circumference of the housing 2, whereby a stator 4 is constituted. The rotary shaft 6 of a rotor is supported by a bearing 7 and a rotor yoke 8 while rotor magnets 9 are attached to the rotor 5. A magnet 10 for frequency generation is fitted to the outer periphery of the rotor yoke 8. The print wiring substrate 1 is provided with a magnetic detecting head 14 while respective detecting means 15-17 of the head are opposed to first-third magnetizing units 11-13 for frequency generation. According to this constitution, respective frequency signals of the first-third detecting means 15-17 are inputted into a sampling circuit 21 and the rotational position of the rotor is detected by a comparing circuit. A signal is outputted from the sampling circuit 21 to a conduction switching circuit 22 and thereby respective phases of the coil 3 may be conducted sequentially. |
