LINEAR VOICE COIL MOTOR WITH NO STRAY FLUX

摘要

A voice coil motor for driving the read/write heads of a magnetic disk drive unit includes an outer elongated enclosure of square cross section and an inner enclosure of similar configuration both of which serve as pole pieces for elongated magnets which are affixed to the inner walls of the outer enclosure. The permanent magnets are polarized so that their axes are perpendicular to the coincident center axis of the elongated enclosures. A slidable element is mounted on a rod extending along this center axis, the slidable element driving the read/write head through an aperture in the end plate of the enclosures. An electric coil of square cross section is mounted in an air gap between the inner pole pieces and the permanent magnets by support fingers which extend through slots in the corner of the pole pieces the supports extending from the movable carrier. By this arrangement all of the flux is contained within the rectangular enclosure and practically no stray flux influences the magnetic recording medium.