| 摘要 |
MULTI-ACTUATOR SYSTEM USING SINGLE MAGNETIC CIRCUIT A voice coil motor having a plurality of independent coils movable within annular flux gaps which are supplied in parallel with flux from a single permanent magnet. The actuator comprises a single permanent magnet mounted to a low reluctance backing plate, a plurality of pole pieces, and a low reluctance casing including an integral pole plate provided with a like plurality of pole piece receiving apertures. The casing extends from the perimeter of the pole plate portion to the backing plate completely surrounding the pole pieces, coils and the magnet. Each pole piece has a rectangular base attached to the permanent magnet and a cylindrical portion which extends into the pole plate portion to define the annular gap, the axis of which is generally normal to the permanent magnet. Adjacent pole pieces abut each other along one edge to assist in maintaining a balanced magnetomotive force to the pole pieces. The axial length of the coil is less than the axial length of the annular air gap to provide a short coil long gap type of actuator and thereby minimize any interaction between the separate parallel flux paths which extend from the permanent magnet. |
