| 摘要 |
PURPOSE:To diminish an eddy current and to move a movable member at high speed by winding a coil around the shaft of a yoke of the ferromagnetic member comprising the flanges arranged on both ends of the shaft and providing said movable body consisting of a cylindrical ferromagnetic member so as to surround the yoke and the coil. CONSTITUTION:A part of ferromagnetic material parts 3d, 3e, and 3f of a movable body 3 is cut out in a direction of shaft line to form slits thereby shutting a circulation path for an eddy current and diminishing an eddy current. Also the cylinder 3b weights light as it is formed thinly in order to diminish the eddy current, which functions effectively for obtaining a much accelerated speed. Because coils 7, 8, and 9 are arranged inside the cylinder 3b, it becomes easy to ensure a large cross-sectional area of the magnetic path without enlarging a size of the whole electromagnet. When the coils 7, 8 and 9 are excited, the magnetic circuits designated by hypothetical lines 22, 23; 24, 25; and 26, 27 respectively are formed in the fixed body 2 and the movable body 3. The attracting force between a side plate 3a of the movable body 3 and an internal end plane of a base 6 which is produced by excitation of a coil 19 moves the movable body 3 to the right. Thus the movable body 3 can be moved at high speed and the position after movement can be maintained by less consumption of electric power. |
