| 摘要 |
A magnetostrictive linear displacement detector includes a dual pole magnet assembly. The displacement detector includes a magnetostrictive wire, a return wire and a magnet disposed for displacement along the magnetostrictive wire. A torsional strain sensor at the head end generates an electrical indication of the torsional strain within the magnetostrictive wire induced by passage of an electrical excitation by the position of the magnet. The magnet of this invention is a cylindrical magnetic bipole. The magnet includes two toroidal magnet sections. The first toroidal magnet section has radially disposed magnetic poles with the South pole directed inwardly and the North pole directed outwardly. The second toroidal magnet is a similar radial magnet except that it has its North pole directly inwardly and its South pole directly outwardly. The magnet assembly has a length preferably no more than one half inch. This length should be short in relation to the total length of the measurement range. This dual pole magnet assembly may also be used in a reciprocal system by producing a torsional strain at the head end and detecting an electrical response when the torsional strain passes the dual pole magnet assembly.
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