| 摘要 |
PURPOSE:To enhance accuracy of the stopping position of a door in which magnetic field of a permanent magnet is mounted on its top and that its opening/closing is driven by a travelling magnetic field generated by an armature mounted on the bottom of the upper frame of a door frame. CONSTITUTION:The gap (A) between the projecting magnetic poles of armatures and permanent magnets 11 used as magnetic poles within the width of a door in a specified section in the position of the door that requirs accuracy of its position at the stopping time is made larger than the gap (B) in the remaining section, and cogging force that acts on the door in its moving direction is reduced by constructing the projecting magnetic poles of respective phase armatures in this section with plural small projecting magnetic poles, and coiling small winding round respective small projecting magnetic poles. |
