JPH09116993

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DESCRIPTION JPH09116993
[0001]
BACKGROUND OF THE INVENTION In the present invention, in order to convert the pressure in
water into a voltage by utilizing the piezoelectric effect and to generate the pressure in water by
the voltage conversely, a wire is provided in a sealed case having a plurality of flats, The present
invention relates to an underwater vibrator in which a multilayer piezoelectric ceramic is
provided inside each plane of a case.
[0002]
2. Description of the Related Art A conventional underwater vibrator is provided with a Langevintype vibrator inside a mold-type sealed case having one plane as shown in FIG. It was common to
perform pressure and voltage conversion.
[0003]
[Problems to be solved by the invention] a.
The conventional underwater vibrator used the resonance frequency of thickness oscillation of
the Langevin type vibrator. In general, since the resonance frequency of thickness vibration is
high, there is a drawback that the efficiency is low when converting a low frequency pressure
like an ocean wave to a voltage. ロ. When the resonant frequency of the Langevin-type vibrator
was to be matched to a low frequency like the wave of seawater, the size of the vibrator became
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large, and the structure of the sealed case became complicated, and the whole became heavy. ハ
. The mold-type sealed case had only one flat surface, and the Langevin vibrator was in contact
with water on only that one surface, so the contact area with water was small, and the amount of
electricity that could be converted from the pressure of water was low. The present invention
was invented to solve these drawbacks.
[0004]
[Means for Solving the Problems] In order to solve the above problems, the underwater vibrator
according to the present invention is characterized in that multilayer piezoelectric ceramics are
provided inside each plane of a sealed case having a plurality of planes. I assume.
[0005]
In the above structure, the multi-layer piezoelectric ceramic provided on the inner side of each
plane of the sealed case performs bending vibration integrally with each plane of the sealed case
by the pressure in the water, so the resonance frequency becomes low. Close to the frequency of
seawater waves, pressure and voltage conversion efficiency increases.
Moreover, since it has a plurality of planes, the area in contact with water is increased, and the
amount of electricity converted from the pressure of water is increased.
[0006]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the underwater
vibrator according to the present invention will be described below with reference to the
attached drawings. As shown in FIG. 1 and FIG. 2, the underwater vibrator is provided with an
electric wire (2) in a closed case (1) having a plurality of flat surfaces, and a multilayer
piezoelectric ceramic (3) provided on the inner side of each flat surface. Is configured.
[0007]
As shown in FIG. 2, the multilayer piezoelectric ceramic (3) is polarized in the direction opposite
to each other in the thickness direction for each layer, and is provided inside each plane of the
sealed case (1).
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[0008]
The present invention has a structure as described above, and when it is used, the multilayer
piezoelectric ceramic (3) flexurally vibrates with each plane of the closed case (1).
Therefore, the resonance frequency is lowered and approaches the wave frequency of seawater,
and the conversion efficiency of pressure and voltage becomes high. In addition, since the
multilayer piezoelectric ceramic has a larger electrostatic capacity than a single layer type, the
amount of converted electricity increases and the conversion efficiency as energy also increases.
[0009]
As apparent from the above description, according to the present invention, the multilayer
piezoelectric ceramic provided on the inner side of the flat surface of the sealed case having a
plurality of flat surfaces flexurally vibrates with the flat surface of the closed case. Because the
resonance frequency becomes lower and approaches the wave frequency of seawater, the
conversion efficiency of pressure and voltage by the piezoelectric effect becomes higher. In
addition, since the electrostatic capacitance of the multilayer piezoelectric ceramic is large, the
conversion efficiency as energy also becomes high. 1 and 2 show an example in the case of two
planes, but it is easy to increase to three or more polyhedrons, and if the number of planes is
increased in this way, a multilayer type is obtained. As the contact area between the piezoelectric
ceramic and seawater increases, more water pressure can be converted into electrical energy.
Therefore, the underwater vibrator with extremely good characteristics can be obtained by the
simple structure.
[0010]
Brief description of the drawings
[0011]
1 is a perspective view showing an embodiment of the underwater vibrator according to the
present invention.
[0012]
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2 is a cross-sectional view of the underwater vibrator shown in FIG.
[0013]
3 is a structural diagram showing a conventional example.
[0014]
Explanation of sign
[0015]
1. Sealed case 2. Electric wire 3. Multilayer piezoelectric ceramic 4. Molded sealed case 5. Cable
6. Langevin type vibrator
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