| 摘要 |
PURPOSE:To simplify the manufacture of a voice coil by disposing a planar coil in an air gap of a magnetic circuit and producing thrust force by poles faced oppositely to the direction of a current flowing through the coil. CONSTITUTION:A magnet 2 is securd to a magnetic circuit 1. Yokes 4 are installed at the oppositely facing positions. A coil 3 wound in a planar state of movable structure is placed in the air gap between the magnet 2 and the yokes 4. Since a current is flowed through the coil 3 at this time, the directions of the currents in the magnetic field are opposite. Thus, the thrust forces produced in accordance with Fleming's left hand law becomes the same direction. In this manner, the coil 3 can move in the air gap between the magnet 2 and the yokes 4. Accordingly, it is not necessary to magnetically connect the magnetic circuit 1 to the yokes 4, and the magnet 2 can be produced in an integral construction. |
