MAGNETOSTRICTIVE LINEAR DISPLACEMENT TRANSDUCER UTILIZING AXIAL STRAIN PULSES

摘要

A magnetostrictive linear displacement transducer includes an elongated member of a material with a large magnetostriction coefficient. There is a coil and a pulse driver for magnetizing the member to cause a detectable magnetostrictive effect for short discrete periods of time. A magnet is movable along the path adjacent the member and is capable of magnetizing a localized portion of the member adjacent the magnet efficiently to cause an alteration in the magnetostrictive effect in the localized portion in concert with the pulse driver and the coil. There is a piezoelectric device at one end for detecting axial strain pulses propagated along the member caused by the magnetostrictive effect. There is a comparator for measuring time lags between initiation of each separate discrete period of time and detection of a corresponding strain pulses by the piezoelectric device and thereby a position of the magnet along the path.