| 摘要 |
A voice coil type actuator wherein the length in an axial direction and the number of parts is reduced without deteriorating a required function and the magnetic flux density in a space in which a movable coil is located is substantially uniform over the entire length in an axial direction. The voice coil type actuator comprises a fixed guide shaft having a radial portion made of a permeable material and a movable body supported for axial sliding movement on the guide shaft. The movable coil is supported coaxially with the guide shaft on the movable body. A yoke having a substantially cylindrical profile is disposed in such a manner as to surround a range of movement of the movable coil, and a pair of fixed magnets are disposed in contact with the guide shaft and the yoke and magnetized with the opposite polarities in a radial direction. The yoke has a recess formed therein in the axial direction of the yoke, and a movable member to be moved by the actuator is supported at a portion of the movable body which extends laterally through the recess in the yoke.
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