close

Вход

Забыли?

вход по аккаунту

?

JPH0775188

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH0775188
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
underwater receiver, and more particularly to an underwater receiver used for towing in water
for acoustic measurement in the ocean.
[0002]
2. Description of the Related Art FIG. 2 is a schematic cross-sectional view showing an example of
a conventional underwater wave receiver for towing. The figure shows an axisymmetric
underwater receiver, but the asymmetrical ones have the same basic configuration and operation.
In the figure, reference numeral 21 denotes an electro-acoustic transducer in which a
piezoelectric ceramic such as PZT (lead titanate) is formed as an acoustic sensor material.
Further, 22 is a sealed rubber hose used as a rubber elastic container having sound permeability,
23 is a signal cable which doubles as a tow cable, 24 is an electrode (not shown) of the
electroacoustic transducer 21 in the rubber hose 22 It is a lead wire connecting the signal cable
23. An insulating fluid 25 is filled inside the rubber hose 22. The above-mentioned closed rubber
hose 22 is considered to reduce the fluid resistance at the time of towing, and is molded so as to
be as smooth as possible within the range not affecting the acoustic characteristics.
[0003]
04-05-2019
1
In this underwater receiver, an incoming sound wave passes through the rubber hose 22 and the
insulating fluid 25 to reach the electroacoustic transducer 21 where it is converted into an
electrical signal. The electric signal is detected by an external circuit (not shown) through the
signal cable 24.
[0004]
SUMMARY OF THE INVENTION In the conventional underwater wave receiver as described
above, the electroacoustic transducer is operated while being towed in water corresponding to
the purpose of use. Turbulence of water is generated on the surface of the rubber hose. The
turbulent flow causes the surface of the rubber hose to vibrate, and accordingly the insulating
fluid filled inside the rubber hose vibrates. As a result, the insulating fluid collides with the
electroacoustic transducer, and the reaction force is converted into electricity and output as
noise. This noise is the main cause of the problem of lowering the signal-to-noise ratio of
detection, and has been a major obstacle especially to weak sound wave detection.
[0005]
The present invention has been made to solve the problems as described above, and prevents
collision of the oscillating fluid generated by towing on the electroacoustic transducer, and
reduces the noise level converted to electricity, thereby reducing SN. An object of the present
invention is to provide an underwater receiver capable of sound wave detection with a good
ratio.
[0006]
SUMMARY OF THE INVENTION An underwater receiver according to the present invention uses
an electroacoustic transducer provided in a rubber elastic container as an acoustic sensor, and is
used in a tow condition in water. An electro-acoustic transducer formed of a piezoelectric ceramic
is provided inside a hollow rigid shell having an acoustic entrance, and made of piezoelectric
ceramic, which is acoustically transparent and directly receives the pressure of an external fluid
by towing. The aforementioned shell is supported by an elastic material inside the elastic
container, and the inside of the rubber elastic container is filled with a fluid.
It is particularly preferable that the hollow shell made of the above rigid body is formed of a high
density rigid material.
04-05-2019
2
[0007]
In the present invention, the electroacoustic transducer provided in the rubber elastic container
is disposed inside a hollow shell made of a rigid body having an acoustic entrance, and the shell
is supported by an elastic material. Since the inside of the rubber elastic container is filled with a
fluid to constitute an underwater receiver, the fluid filled inside is vibrated by the vibration
caused by the turbulent flow generated on the surface of the rubber elastic container when the
underwater receiver is towed. However, since the oscillating fluid first strikes the shell, the shell
does not act as a shield and directly collide with the electroacoustic transducer. Therefore, since
the noise N of the SN ratio decreases, the SN ratio increases when the signal S is constant.
[0008]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a schematic crosssectional view showing an embodiment of a tow underwater receiver according to the present
invention. FIG. 1 shows an axially symmetric underwater wave receiver as an example. In the
figure, reference numeral 11 denotes an electro-acoustic transducer in which a piezoelectric
ceramic such as PZT (lead titanate) is formed as an acoustic sensor material. Further, 12 is a
sealed rubber hose used as a rubber elastic container having sound permeability, 13 is a signal
cable which also serves as a tow cable, 14 is an electrode (not shown) of the electroacoustic
transducer 11 in the rubber hose 12 It is a lead wire which connects with the signal cable 13. An
insulating fluid 15 is filled in the rubber hose 12. The apparatus configuration up to this
explanation is the same as the configuration of the conventional apparatus of FIG.
[0009]
The underwater wave receiver according to the present invention is characterized in that the
electroacoustic transducer 11 is disposed in a hollow rigid shell 16 as seen in FIG. Here, the shell
16 has an aperture-like acoustic entrance 17. Also, the shell 16 has dimensions sufficiently small
with respect to the wavelength of the incoming sound wave, and is nondirectional. The shell 16 is
supported by an elastic material (not shown) and disposed substantially at the center of the
rubber hose 12. Furthermore, although the shell 16 serves as a well-known Helmholtz resonator,
the dimensions of the sound inlet 17 and the size of the shell 16 are such that their resonant
frequency is higher than the used (detected) frequency band. Volume is set.
04-05-2019
3
[0010]
In the present underwater wave receiver, an incoming sound wave passes through the rubber
hose 12 and the insulating fluid 15, enters from the acoustic entrance 17 of the shell 16, reaches
the electroacoustic transducer 11, and is converted into an electric signal here. The electrical
signal is detected by an external circuit (not shown) through the signal cable 13.
[0011]
Here, the operation for noise reduction by the installation of the shell 16 will be described. When
the underwater receiver is towed, turbulence is generated on the surface of the rubber hose 12.
The turbulent flow causes the surface of the rubber hose 12 to vibrate, and accordingly the
insulating fluid 15 filled inside the rubber hose vibrates. The oscillating fluid collides with the
shell 16. In this case, the shell 16 serves to prevent the oscillating fluid from directly colliding
with the electroacoustic transducer 11. That is, the shell 16 acts as a kind of shield to prevent it
from directly affecting the fluid vibration.
[0012]
As another example, the case where the shell 16 is formed of a high density material will be
described. In this case, the shell 16 vibrates by the total force of reaction forces against the
impact of the vibrating fluid, but when the mass of the shell 16 increases for the same external
force, the magnitude of the vibration decreases, and the internal electroacoustic conversion is
performed. The vibration acceleration of the element 11 is also reduced. Therefore, the noise
output of the electro-acoustic transducer 11 due to acceleration can be further reduced than in
the case of the shell 16 made of a material of lower density. Therefore, the noise reduction effect
is greater than in the previous embodiment.
[0013]
As described above, according to the present invention, an electroacoustic transducer composed
of piezoelectric ceramic provided in a rubber elastic container is disposed inside a hollow shell
04-05-2019
4
composed of a rigid body having an acoustic entrance. Since the underwater receiver is formed
by filling the inside of the rubber elastic container with fluid, the inside of the rubber elastic
container is filled with vibration due to the turbulent flow generated on the surface of the rubber
elastic container when the underwater receiver is towed. Even if the fluid vibrates, the vibrating
fluid first strikes the shell, so it does not collide directly with the electroacoustic transducer, and
an effect capable of achieving an underwater receiver capable of sound detection with
significantly reduced noise. Is obtained. Furthermore, by forming the shell with a high density
material, it is possible to suppress the vibration of the shell more than in the case of the low
density one, and reduce the electrical output due to the acceleration of the vibration of the
electroacoustic transducer placed inside effective.
04-05-2019
5
Документ
Категория
Без категории
Просмотров
0
Размер файла
13 Кб
Теги
jph0775188
1/--страниц
Пожаловаться на содержимое документа