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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
low frequency transmitter in water.
2. Description of the Related Art Heretofore, as a technique in such a field, for example, a low
frequency wave transmitter made into a cylindrical shape by combining trapezoidal active
electrons and Koichi Koichi, Koichi Koichi 3 and others [3] , Ocean Acoustics Research Report,
10, 2 (1983), pp. 67-74.
As shown in the above-mentioned document, conventionally, this type of sound source is
transmitted using a cylindrical integral piezoelectric.
FIG. 4 is a schematic block diagram of such a conventional low frequency wave transmitter, and
FIG. 4 (a) is a top view thereof, FIG. 4 (b) is a cross sectional view taken along line AA of FIG. c) is
a cross-sectional view taken along the line B-B in FIG.
As shown in these figures, in order to lower the frequency of the sound source, the trapezoidal
piezoelectric electrons 1 are stuck in a circumferential shape to increase the size of the drive
portion. Furthermore, piezoelectric electrons are electrically stacked in parallel to supply input
power from the lead wire 3. In addition, glass fiber 2 is prestressed to prevent the destruction of
piezoelectric electrons.
Alternatively, as a method conventionally used in addition to the above-described manufacturing
method, a method of manufacturing cylindrical piezoelectric electrons and transmitting waves
using a circumferential breathing mode has been used.
However, in the low frequency transmitter of the above configuration, dimensional accuracy is
important for arranging trapezoidal piezoelectric electrons in a circumferential shape, and it is
difficult to make the size larger than that.
Also, in order to lower the resonance frequency as a transmitter, it is necessary to make the
diameter larger, so it has been difficult in the conventional method to lower the frequency than 5
KHz realized by this sound source. In addition, the manufacturing process is also complicated in
order to give prestress for preventing destruction with glass fiber.
In addition, the circumferential piezoelectricity is limited in the size that can be manufactured
integrally in manufacturing, and can only be a sound source of several KHz at most. The present
invention eliminates the above-mentioned problems and enlarges the drive part of the sound
source, thereby achieving ultra-low frequency at KHz or lower, making the drive part of the
sound source one unit, various combinations depending on the combination of units An object of
the present invention is to provide an underwater low frequency wave transmitter which can be
driven at a frequency and which can be connected to a connection fitting of a unit to simplify a
manufacturing process.
SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a
low frequency transmitter for water, which comprises a stacked piezoelectric stack, a connection
fitting, and the piezoelectric stack. A drive unit is formed by clamping a prestress bolt with a
connection fitting, and a polygonal circumferential piezoelectric assembly is formed by joining
adjacent connection fittings of the drive unit.
According to the present invention, as described above, instead of the conventional method in
which trapezoidal piezoelectric electrons are arranged circumferentially and stacked, or the
method using integral cylindrical piezoelectric electrons, a plate of piezoelectric electrons is used.
By using a stack of several tens of sheets as one drive unit and connecting the drive units in a
circumferential manner, it is possible to increase the size without being limited by the
manufacturing technology limitations of piezoelectric and lamination. Therefore, it is possible to
transmit at several hundreds Hz, which could not be achieved conventionally.
Furthermore, it is possible to give directivity to the sound source by inputting an alternating
current whose phase is different for each drive unit.
invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram of an underwater low frequency wave transmitter (sound source)
showing an embodiment of the present invention, and FIG. 1 (a) is a perspective view of a drive
unit portion of the underwater low frequency wave transmitter. (B) is a whole perspective view of
the underwater low frequency wave transmitter, FIG. 2 is a sectional view taken along the line AA
of FIG. 1 (b), and FIG. 3 is a sectional view taken along the line BB of FIG. .
First, as shown in FIG. 1A and FIG. 2, the piezoelectric electron flat plate is vertically stacked
several dozens on a straight line to form one set, and the stacked piezoelectric electron stack 11
is connected by the connection fitting 12. The drive unit 10 is manufactured by tightening the
clamp pre-stress bolt 13 and then, as shown in FIG. 1 (b), FIG. 2 and FIG. Form a polygon.
Therefore, a voltage is applied to the piezoelectric stack 11 by the lead wire 14 connected to the
terminal of the piezoelectric stack 11 to drive the piezoelectric stack 11.
The vibration is a single resonance in all drive units connected in a polygon, and a single
wavelength mode is a resonant system for the entire circumference.
Therefore, the frequency can be further reduced by using a large number of drive units. In
addition, the periphery of the polygonal drive portion is filled with oil 15 having good acoustic
transparency, and rubber boots 16 are provided on the inner and outer sides thereof to achieve
water pressure balance, making it a structure that can be used in any deep sea. As described
above, a plate of piezoelectric electrons is vertically stacked several dozens on a straight line as
one drive unit, and the drive units are connected circumferentially, so that the manufacturing
technology limit of piezoelectricity and bonding is achieved. It can be enlarged without being
This enables transmission at several hundreds Hz, which could not be achieved conventionally.
Further, in the above embodiment, the adjacent ones of the connection fittings 12 are joined by
the bolts 17, but it is further added to the terminals of each drive unit so that the adjacent ones
of the connection fittings 12 are joined by a strong adhesive. The directivity of the sound source
can be provided by inputting alternating currents having different phases. For example, sound
waves are generated by compression force in the X-axis direction, sound waves are generated by
tension force in the Y-axis direction, their boundaries are null, and directivity is provided in the
X-axis direction and Y-axis direction. It is also possible to
Further, the present invention is not limited to the above embodiments, and various
modifications are possible based on the spirit of the present invention, and they are not excluded
from the scope of the present invention.
[Effect of the invention] As described above in detail, since upsizing of the sound source can not
be conventionally made, transmission at resonance can be made only in the KHz order, but
according to the present invention, upsizing of the sound source is made. Therefore, the
resonance frequency can be lowered to several hundreds Hz, and an underwater low frequency
transmitter (sound source) that can obtain a large output at a low frequency can be realized.
In addition, since the shape of the sound source is determined by the combination of the drive
units, various combinations can be obtained, and manufacturing change of the sound source is
Furthermore, the manufacturing process can be simplified by joining the connection fitting of the
drive unit.