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Complementary Forces Voice Coil Motor

IP.com Disclosure Number: IPCOM000052263D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Nguyen, LT: AUTHOR [+2]

Abstract

The figures illustrate a voice coil motor which has been constructed to minimize the nonlinearity and variations of the push-pull forces normally associated with prior-art voice coil motors.

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Complementary Forces Voice Coil Motor

The figures illustrate a voice coil motor which has been constructed to minimize the nonlinearity and variations of the push-pull forces normally associated with prior-art voice coil motors.

The improved voice coil motor 9 is shown in Figs. 1a and 1b with the moving coil omitted for clarity. The motor 9 comprises an outer housing 10 which may be steel tubing, a pair of magnets 11A and 11B which, as shown, are circular in cross-section and may be made from ceramic magnetic material, and inner concentrating poles 13A and 13B which also may be made of steel tubing. The motor further comprises a center pole piece 15 of solid circular cross-section which is attached to a non-magnetic baseplate 16, the circumferential side 17 of which attaches to the housing 10. An inductance ring 18, consisting of copper, may also be inserted adjacent to the steel concentrating poles 13, as shown.

The basic subassembly shown in Figs. 1a and 1b is advantageously assembled by shrink fitting the various elements having circular cross-sections onto each other.

Fig. 2 shows a cross-section of the motor illustrating the magnetic polarity of the magnets 11A and 11B and shows the coil winding for the movable coil 19 which surrounds center pole 15 and moves in the annular flux gap 20 defined by pole piece 15 and ring 18.

Fig. 3 shows the free body diagrams illustrating the various forces involved on the moving coil in the push direction and the pull direct...