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Method for Fabrication of a Shorted Turn Assembly

IP.com Disclosure Number: IPCOM000046692D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Block, EE: AUTHOR [+2]

Abstract

The permanent magnet portion of voice coil actuator is shown with a part cut away in Fig. 1 and in section in Fig. 2. It has an outer housing 1 of magnetic material and a cylindrical magnet 2. A shorted turn 3 has flared ends 4 and 5 which bear against end seals 6 and 7, respectively. In the case where the permanent magnet is made of flexible material, it is important that there is good contact between the outer surface of magnet 2 and the inside of outer housing 1. Fabrication of the assembly is accomplished by placing the magnet 2 and end seals 6 and 7 inside the housing 1. The shorted turn 3, of copper or other soft conducting material, is positioned with the ends equidistant from the end seals 6 and 7.

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Method for Fabrication of a Shorted Turn Assembly

The permanent magnet portion of voice coil actuator is shown with a part cut away in Fig. 1 and in section in Fig. 2. It has an outer housing 1 of magnetic material and a cylindrical magnet 2. A shorted turn 3 has flared ends 4 and 5 which bear against end seals 6 and 7, respectively. In the case where the permanent magnet is made of flexible material, it is important that there is good contact between the outer surface of magnet 2 and the inside of outer housing 1. Fabrication of the assembly is accomplished by placing the magnet 2 and end seals 6 and 7 inside the housing 1. The shorted turn 3, of copper or other soft conducting material, is positioned with the ends equidistant from the end seals 6 and 7. This is easily accomplished because the shorted turn has an initial outside diameter which provides a clearance fit inside the magnet 2. The expansion tool, shown in Fig. 3, is then positioned inside the shorted turn, as shown in Fig. 4. Bolt 11 is then turned into collar 8, causing the elastomer mandrel 9 to be compressed between collar 8 and collar 10. The resulting radial expansion of mandrel 9 causes the ends of shorted turn 3 to be flared and turn 3 to be expanded to press the magnet 2 firmly against housing 1. Since the outer diameter of mandrel 9 in the relaxed state is less than the expanded diameter of shorted turn 3, the mandrel is easily removed by simply turning bolt 11 several turns out of collar 8...