Non-contact displacement sensor and displacement method of detection

摘要

PURPOSE:To improve the resistance against electromagnetic noise and to improve detecting accuracy by improving frequency characteristics by providing a detecting coil and an inductance detecting means. CONSTITUTION:A detecting coil 1 is formed by forming a winding 3 around a core 2 wherein thin plates of iron-based amorphous alloy whose high-frequency loss is small are laminated. Both ends of the core 2 are made to face an object 4 and arranged at a fixed state. An oscillator 5, an detector 6 and a filter 7 constitute a inductance detecting means. In this constitution, when an AC at a high frequency is supplied to the winding 3 from the oscillator 5, the increase in magnetoresistance of the core 2 in the closed magnetic path constituted of the detecting coil 1 is suppressed. Therefore, magnetoresistance component caused with a gap epsilon becomes large, and the inductance change due to the displacement of the object 4 becomes large. Thus sensitivity is improved. When the oscillating frequency of the oscillator 5 is set in the flat region of the inductance, the inductance with respect to the modulated wave caused by the displacement of the object 4 becomes approximately constant, and the measuring accuracy is improved.