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Balanced Force Voice Coil Actuator

IP.com Disclosure Number: IPCOM000077469D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Frater, NK: AUTHOR

Abstract

This is a voice-coil motor which contains two moving masses to eliminate reaction forces transmitted by the coils to the magnet. Two coils 1, 2 are supported in the magnetic gap of the motor by two carriages 3, 4. Each carriage holds a set of arms and magnetic heads, and each is constrained by bearings to permit only radial motion of the magnetic heads relative to the disks. The carriages are coupled together by a reversing mechanism 5 to register (not impart) equal and opposite displacements of the two carriages.

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Balanced Force Voice Coil Actuator

This is a voice-coil motor which contains two moving masses to eliminate reaction forces transmitted by the coils to the magnet. Two coils 1, 2 are supported in the magnetic gap of the motor by two carriages 3, 4. Each carriage holds a set of arms and magnetic heads, and each is constrained by bearings to permit only radial motion of the magnetic heads relative to the disks. The carriages are coupled together by a reversing mechanism 5 to register (not impart) equal and opposite displacements of the two carriages.

The total mass of one carriage, coil, arms and heads is made equal to the total mass of the other carriage, coil, arms and heads. One coil is wound with the identical number of turns of wire as the other coil, but in the opposite direction. Thus when current is passed serially through the coils, equal and opposite forces are generated in the coils which impart equal and opposite accelerations~ to the two carriages, coils, arms and heads. The net reaction force exerted by the coils on the magnet is zero.

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