| 摘要 |
PURPOSE: To reduce the ripple of the driving force of a door by arranging the door, on which a moving piece for a switched reluctance type linear motor is fixed, to a door frame, to which a stator for the linear motor is fitted, in a freely travelling manner and controlling the energization of an armature coil from the positional relationship of the stator and the moving piece. CONSTITUTION: A magnetic pole section 2 as a moving piece R is fixed onto a hanger 53 and an armature 1 as a stator S at a midpoint within the range of the travelling of a door 5. A position sensor detecting optically detecting the relative positional relationship of pole teeth 11 and salient poles 21 from three rows of light-dark pattern fringes formed to the side face of the moving piece R is disposed onto the side face of a door frame 6, and relative positions are detected on the basis of pole pitches among the four pole teeth 11 by the combination of the light and darkness. When armature coils 12 having three phase are energized, static driving force at every phase is changed by the movement of the door 5, but energization of the coils 12 having each phase is changed over at specified timing by using an output from the position sensor, thus preventing the working of detent torque, then reducing a ripple in driving force working to the door. |
