| 摘要 |
PURPOSE:To uniform force applied to the movable coil of an actuator by increasing the length of a permanent magnet in the rectangular direction of the arc locus of a moving coil from the center part of the movement range of the movable coil to the external end part. CONSTITUTION:In a housing 6 made of a nonmagnetic material, permanent magnets 9, 10, 11, and 12 for producing magnetic fields coupled magnetically by yokes 7 and 8 corresponding to the plane coil part 5 on a coil substrate 4 are provided. Then, the permanent magnets 9, 10, 11, and 12 increase in length perpendicular to the arc locus of the coil 5, put in arc motion shown by an arrow A, from the center part of the movement range (e.g., from Q1 to Q2 as to permanent magnet 11) of the coil 5 to the external end part. Therefore, the intensity of a magnetic field at each end part of the permanent magnet becomes greater than that at the center part, thereby compensating the leakage of magnetic flux (not operating on the coil 5) at the end part. Consequently, force operating on the coil 5 is nearly uniformed between the movement range Q1Q2 of the coil 5. |
