PURPOSE: To miniaturize a magnetic circuit by a method wherein a permanent magnet is formed so that the cross-sectional area, in which a coil is superposed on the permanent magnet, is increased as the coil approaches from the center of the permanent magnet to either end of the same while the left and right ends of the permanent magnet are made to fit the size of the coil when the coil is positioned at the left and right maximum swinging angles in the required swinging area of the same.
CONSTITUTION: A permanent magnet 16 is formed so that the cross-sectional area, in which a coil 20 is superposed on the permanent magnet 16, is increased as the coil 20 approaches from the center Sc of the permanent magnet 16 to either end Se of the same while left and right ends Me of the permanent magnet 16 are made to fit the coil 20 respectively when the coil 20 is positioned at the left and right maximum swinging angle positions in the required swinging area of the same. In this case, the inside rim Mi and the outside rim Mo of the permanent magnet, which are along the locus C of the swinging arc of the coil 20, are provided with the centers Oi, Oo of curvatures at the side of the supporting point Oc of the shaft of a movable member while the radius of curvature Ri of the inside rim Mi is designed so as to be smaller than the radius of curvature Ro of the outside rim Mo of the magnet.
| JPH08249837 | DISK DRIVER |
| JP2003529176 | Description: An actuator having kinetic symmetry. |
NAKANO HIROFUMI
MATSUI KAZUO
| JPS6354863A | 1988-03-09 | |||
| JPS63140655A | 1988-06-13 | |||
| JPS5930619U | 1984-02-25 |