| 摘要 |
PURPOSE:To reduce the size of a position detecting magnet by employing a sole magnet having a width of 180 deg. of electric angle for the detecting magnet, and combining outputs of position detectors disposed at he special positions as position detection signals. CONSTITUTION:A 4-pole brushless motor is composed by press-fitting a stator 13 having a winding 12 to a stator frame 11 and arranging a rotor 14 made of a permanent magnet in a field space. A position detecting magnet 20 is mounted at the end projected from a bracket 17 of opposite load side of its rotational shaft 15. The magnet 20 has a width of 180 deg. of electric angle and is magnetized radially. Six position detectors 21-26 are mounted on the inner surface of an annular mounting jig 28 mounted on a bracket 17 and disposed at 120 deg. of electric angle on the outer periphery of the magnet 20. Thus, the detectors 21-26 turn ON and OFF switching elements which energize the phases of the stator windings 12 by a control circuit through an amplifier and an OR gate. |
