JPS61230599A - Wide band underwater sound wave transmitter - Google Patents

Abstract

PURPOSE:To transmit a wide band sound wave by providing plural holes in circumference-shaped at the intermediate of a wall thickness part on a shell and making a cylindrical piezoelectric ceramic vibrator having a taper on its outside to inscribe to the inside of the shell. CONSTITUTION:A shell 1 is formed as a cylinder with a wall thickness and plural holes 2 are provided on the wall thickness part and it is taper-processed so that a cylindrical piezoelectric ceramic vibrator 3 having the taper on its outside is inscribed with the inside of the shell. The vibrator 3 is fixed at the shell 1 with an insulating washer 4, a bush 5 and a bolt 6. At such a time, an appropriate circumference directioned compression bias stress is given on the vibrator 3 and by adding an electrical signal on the electrodes of outside and inside of the cylinder of the vibrator 3 with lead wires 8 and 9, the vibrator 3 is driven. And by setting the outside of the shell 1 underwater, it is possible to transmit the underwater sound wave with a very wide band area from the outer plane of the shell 1 to the water.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an electroacoustic transducer for utilizing underwater sound waves,
In particular, the present invention relates to a wideband underwater acoustic wave transmitter that responds with wide frequency characteristics.

[Background of the invention]

Conventional underwater sonic wave transmitters have f/f,
The transmission sensitivity was almost constant up to about 2. However, depending on the purpose of using underwater sound waves, there are cases where a completely constant area is required, and cases where a method that responds to a broader band even if there is a slight slope is required. Natural noise characteristics generally have an extremely wide band with a slope of -6 dB10 ct. However, no consideration was given to the transmission characteristics for application in such situations.

[Purpose of the invention]

The purpose of the present invention is to make the output constant with respect to the frequency, which is the frequency characteristic that nature generally has, that is, the sound pressure is 16
At about dB10ct, the fundamental resonant frequency f, f/
The object of the present invention is to provide a broadband underwater sonic wave transmitter that can be used in an extremely wide range of applications where f0 is 5 to 6.
In order to achieve broadband characteristics with j/f0 of 5 to 6 relative to 0, the complex resonance characteristics of the structure are utilized, and a sound wave radiation vibration shell (hereinafter referred to as shell) is provided with 1111 holes. It is constructed to have complex vibrations and is driven by a piezoelectric ceramic vibrator.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention is shown in FIGS. 1 and 2(a),
(b) Explain from K. In FIG. 1, a shell 1 is a thick-walled cylinder, a plurality of holes 2 are provided circumferentially in the middle of the thick-walled part of the shell, and a cylindrical piezoelectric ceramic vibrator 3 whose outer side is tapered inside the shell. It is tapered so that it is inscribed. The piezoelectric ceramic vibrator 3 has electrodes on its inner and outer surfaces, and is designed to perform respiratory vibrations.Insulating washers 4 are used to electrically insulate the inside and outside of the tapered piezoelectric vibrator 3, which are arranged to face each other. Apply it to the large diameter part, and push bolt 6 and nut 7 through a-5.
Conclude with. At this time, when the bolt 6 and nut 7 are tightened, the inner taper of the shell 1 and the outer taper of the piezoelectric ceramic vibrator 3 come into contact, and the piezoelectric ceramic vibrator 3 receives a compressive force in the circumferential direction. At this time, considering the processed surface roughness of the taper of the shell 1 and the external taper of the piezoelectric ceramic vibrator 3, an extremely thin (
If used, stable surface contact can be obtained. The compressive stress in the circumferential direction of the piezoelectric ceramic vibrator 3 caused by fastening the bolt 6 and nut 7 inevitably becomes the bias compressive stress of the piezoelectric ceramic vibrator 3, and when this vibrator is forcibly excited with high power, This is to strengthen the weak point in the unique tensile strength, and the magnitude of the bias stress may be determined by taking into consideration the amplitude of the vibration stress of forced excitation. In the figure, 10 is a lid, and 11 is an O-ring.

In such a configuration, if the inner and outer electrodes of the piezoelectric magnetic vibrator 3 are electrically excited using the leads 8 and 9, the piezoelectric magnetic vibrator 3 mechanically drives the inside of the shell 1, and the shell 1 is heated. Sound waves are emitted from the outer surface of the shell into the water in which it is placed, in accordance with the characteristics of the complex resonance (in this case, it actually has a complex resonance system in which all structures below 3 piezoelectric vibrators intervene). It is something to do. FIG. 3 shows the experimentally determined sound pressure versus frequency characteristics of the sound waves radiated into the water from the outer surface of the shell in this configuration.

In FIG. 2, the lowest resonance point is fo, and f/f.

Although an example up to =6 is shown, this slope characteristic differs depending on the size of the hole 20 formed in the shell 1, the number of holes, etc. Therefore, if a plurality of holes are machined according to the purpose, the effect will be great.

〔Effect of the invention〕

As described above, the transmission sensitivity frequency characteristic according to the present invention has a slope of approximately 16 dB10 ct from the fundamental resonance frequency #fo, that is, f/f0=1, to f/fo=-s, and There are no idiosyncratic response characteristics that pose a major obstacle (
In good condition. With respect to the frequency, this frequency characteristic is 16d
Being B10ct means that if the input power is constant, the input power has characteristics that are almost constant with respect to frequency, so it has the effect of having response characteristics that can transmit extremely wide-band underwater sound waves. It is possible to freely conduct electroacoustic conversion of wideband signals such as white noise or frequency-modulated signals.

[Brief explanation of drawings]

Figures 1 to 3 all show one embodiment of the present invention. Figure 1 is a cross-sectional view showing the structure of a broadband underwater acoustic wave transmitter, and Figure 2 (a) is the same as that of Figure 1. 2m0) is a sectional view taken along line A-A, and FIG. 3 is a characteristic diagram. 1...Sound wave radiation vibration shell

Claims (1)

[Claims] The sound wave emitting vibration shell 1 is made into a thick-walled cylinder, and a plurality of holes 2 are processed and arranged in a cylindrical shape inside the thick-walled cylinder, and a taper is provided on the inside of the thick-walled cylinder to create a cylindrical piezoelectric with an outside taper. The piezoelectric vibrator 3 is inserted and fastened with a bolt 6 and nut 7 via an insulating washer 4 and a pusher 5, and an appropriate compressive bias stress is applied to the piezoelectric vibrator 3 in the circumferential direction. Electric signals are applied to the outer and inner electrodes of the cylinder of the piezoelectric ceramic vibrator 3 to drive them, and the outer surface of the sound wave emitting vibrating shell (shell) is set in water as a medium. A broadband underwater sonic wave transmitter that is characterized by being able to radiate more sound waves into the water.