UNDERWATER TRANSMITTER MADE OF RARE-EARTH ALLOY

摘要

PURPOSE:To attain miniaturization, light in weight and high output by inserting the magnetostriction rod to the center of a magnetic circuit comprising a permanent magnet and a soft ferrite of a magnetic bias application section so as to apply a strong magnetic flux magnetostriction rod and to apply an AC magnetic field efficiently to the magnetostriction rod. CONSTITUTION:A transmitter 30 is provided with a magnetostriction rod 31 made of a high magnetostriction rare-earth alloy. Sets of mass 32, 33 being vibration bodies are fitted directly to both end faces of the magnetostriction rod 31. A cylindrical bobbin 34 with a coil 35 wounded thereon is arranged to an outer periphery of the magnetostriction rod 31. Moreover, a magnetic bias application section 36 of almost cylinder structure around the shaft of the magnetostriction rod is arranged to the outside of the bobbin 34 between the sets of mass 32, 33. The magnetic bias application section 36 forms a magnetic circuit, in which two ring shaped permanent magnets 37, and plural soft ferrite materials 38 of cylinder and doughnut shape being yoke members are laminated. Thus, the magnetic field generated in the permanent magnet 37 is applied efficiently to the magnetostriction rod 31, in which a strong magnetic flux is supplied to the magnetostriction rod 31.