Rare earth giant magnetostrictive composite rod-type transducer

Abstract

The invention discloses a rare earth giant magnetostrictive composite rod-type transducer. The transducer comprises a front radiation head, a rear radiation head, a pre-stressing screw, a rare earth giant magnetostrictive material, a permanent magnet, a coil rack and a wire and is characterized in that the permanent magnet is a hollow circular tube; the rare earth giant magnetostrictive material is a plurality of Terfenol-D circular rods of the same length; the circular rods are uniformly distributed along the circumferential direction of the outer circumference of the permanent magnet; and gaps are remained between the circular rods and the permanent magnet. The transducer also comprises two disk-type magnetic pure iron sheets; and the two magnetic pure iron sheets are arranged between the upper end of the rare earth giant magnetostrictive material and the front radiation head and between the lower end of the rare earth giant magnetostrictive material and the rear radiation head respectively. The magnetic pure iron sheets are provided with radial slots of which the lengths are three fourth of the radius. The transducer effectively overcomes the disadvantages of large eddy current loss and low efficiency when the rare earth giant magnetostrictive material works at a high frequency band.

Description

Technical field [0001] The invention belongs to the field of acoustic sensors. Specifically, the invention relates to a rare earth giant magnetostrictive composite rod transducer. Background technique [0002] The composite rod transducer is a transducer form that is widely used in the underwater acoustic and ultrasonic industries. It is usually used in the frequency range of several kilohertz to tens of kilohertz. The driving materials of the composite rod transducer can be divided into piezoelectric materials and rare earth giant magnetostrictive materials (Terfenol-D). For decades, most of the composite rod transducers are made of piezoelectric materials. The advantages of piezoelectric materials are high electromechanical coupling coefficient, relatively small high frequency dielectric loss, low cost, Easy to prepare etc. Compared with piezoelectric materials, rare earth giant magnetostrictive materials have more excellent characteristics, such as larger strain value, large...

AI Technical Summary

Problems solved by technology

The inventor discloses an ultra-low frequency underwater acoustic transducer in the patent "CN200610065104.6". An integral rare earth giant magnetostrictive material rod is used in each drive unit of the transducer and a A disc-shaped rare earth permanent magnet is pasted on both ends of the magnet, but the biggest disadvantage of the rare earth giant magnetostrictive material is that the eddy current loss is relatively large and the efficiency is low when working in the high frequency band, which greatly limits its use in ultrasonic Application of frequency band

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