JPS62284278

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DESCRIPTION JPS62284278
[0001]
The present invention relates to a baffle on which a transducer or the like is fixedly supported in
a sonar. [Prior Art] A transducer or the like used in a sonar needs to avoid the influence of
unnecessary sound pressure to obtain a predetermined characteristic. Therefore, when
constructing a sonar, the transducer or the like is usually specified. It is fixed to and supported by
the baffle so as to be an arrangement of As conventional baffles of this type, two types of soft
and hard types are known, and as the soft type baffles, for example, a structure in which a small
air chamber is sealed with a rubber material such as neoprene Are known. This is intended to
make use of the property of air having an extremely low acoustic impedance as compared to
water, and aim for completely soft reflection of unnecessary sound pressure incident on the
baffle. Also, a hard type buckle is constructed using a rigid material such as metal, which,
contrary to the soft type baffle, has a high acoustic impedance compared to water and a rigid
reflection. It is aimed at. [Problems to be Solved by the Invention] However, the above-mentioned
two conventional baffles have the problems described below. That is, the soft type baffle shrinks
the air chamber when water pressure is applied, and as a result, the acoustic impedance
approaches water and the sound permeability becomes good, so the buckle function is
significantly reduced, and thus under high water pressure There is a problem that it is impossible
to use On the other hand, is the hard type baffle an acoustic impedance high enough? In the case
of having it, it is necessary to make the thickness of the plate sufficiently large, so that there is a
problem that it becomes very heavy to be usable even at low frequencies. The present invention
has been made to solve these problems, and it is an object of the present invention to realize a
sonar baffle which can be used under high water pressure and which is lightweight and has an
excellent buckle function. [Means for Solving the Problems] In order to achieve the above object,
the present invention is a damping material mainly composed of rubber on the surface of a water
resistant membrane made of a rigid material having a sealed air chamber inside. Is provided.
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[Operation] In the present invention having the above-described configuration, of the sound
pressure incident on the buckle, the high pressure sound pressure is reflected by the water
pressure resistant film, and the low frequency sound pressure transmitted through the water
pressure resistant film is It can be totally reflected by the air in the air chamber inside the shell.
Further, the resonance phenomenon of the water pressure resistant film and the re-radiation of
the sound pressure obliquely incident on the water pressure resistant film are suppressed and
reduced by the damping material adhered to the surface of the water pressure resistant film,
thereby It prevents the disturbance of the wave field of the wave output.
Therefore, according to this, by using the water pressure resistant membrane, the air chamber is
not reduced by water pressure, and the use under high water pressure becomes possible, and the
water pressure resistant membrane is made of a rigid material However, it is possible to reduce
the weight because it is not necessary to increase the thickness of the plate, and to reflect the
incident sound pressure completely by the water resistant film and the air chamber, and at the
same time the sound field of the receiver output by the damping material. Can be prevented, so
that an excellent baffle function that can stabilize the characteristics of the receiver output can
be expected. An embodiment will be described below with reference to the drawings. FIG. 1 is a
front view showing an embodiment of a baffle for a sonar according to the present invention, in
which 1 is a water resistant film, 2 is a damping material (damping material), and 3 is a
transducer. The water pressure resistant film 1 is formed of a rigid material such as metal or
resin so as to withstand high water pressure, and has, for example, a shape having dome shaped
portions on the upper and lower sides of a cylindrical body. Has a sealed air chamber. The
damping material 2 is mainly composed of rubber, and the damping material 2fjc is adhered to
the surface of the water pressure resistant shell 1 to constitute the sonar baffle of this
embodiment, and the transducer 3 is controlled. It is fixed to the outer peripheral surface of the
vibrating material 2 in a predetermined arrangement. In the present embodiment, the damping
material 2 is stuck over 130% of the wave receiving area and 90 tees of the surface area of the
water pressure resistant film 1. Next, to explain the operation of the above-mentioned structure)
First, since the water pressure resistant film 1 is formed of a rigid material, this water pressure
resistant film itself reflects the incident sound pressure of a constant eclipse, that is, the high
pressure sound pressure. Can. Here, although part of the incident sound pressure passes through
the water pressure resistant film 1, the water pressure resistant film 1 can withstand high water
pressure as described above, so the air chamber inside is not shrunk by water pressure, and
therefore The air pressure in the air chamber can completely reflect the sound pressure and low
frequency sound pressure transmitted through the water pressure resistance shell 1. The
frequency characteristics of the sonar baffle in this example are similar to those of the soft type
at low frequencies and near to the hard types at high frequencies, and the sound pressure
reflectance is 1 over the entire frequency band. Because the sound pressure transmittance is
close to O, a sufficient baffle function can be obtained. On the other hand, since the damping
material 2 is mainly composed of rubber, the following functions can be performed without
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causing the impedance equivalent to water to the incident sound pressure of the water pressure
resistant film 1 and the buckle function of the water pressure resistant film 1. Do. That is, when
only the water pressure resistant film 1 made of a rigid material is used as a baffle, a resonance
phenomenon occurs in the water pressure resistant shell 1 due to the incident sound pressure,
and the sound pressure obliquely incident on the water pressure resistant film 1 Is propagated
through the water pressure resistant film 1 and re-radiated, and thereby the sound field at the
receiving point of the transmitter / receiver 3 is disturbed, and the directivity of the receiver
output is disturbed.
Therefore, in the present embodiment, the damping material 2 is attached to the surface of the
water pressure resistant film 1, and the resonance of the water pressure resistant film 1 is
suppressed by the damping material 2 and the reradiation of the propagation sound pressure is
reduced. It is possible to prevent the disturbance of the sound field at the receiving point. FIG. 2
is a diagram showing the horizontal directivity characteristic of the receiver output of the single
CH in the embodiment of FIG. 1, where the diameter of the water resistant film 1 with the
damping material 2 attached is 75 crn and the measurement frequency is 6 KHz The case of is
taken as an example. FIG. 3 shows the horizontal directivity characteristics of the receiver output
of a single channel when only the water pressure resistant film 1 is used as a buckle for
comparison with the embodiment, and the conditions are the same as in the case of FIG. is there.
As is apparent from FIG. 3, the disturbance of the directivity characteristics due to the
disturbance of the sound field is large with the water pressure resistant film 1 alone, but in the
case of the water pressure resistant film 1 with the damping material 2 attached thereto, In this
case, as shown in FIG. 2, disturbance of the directional characteristics does not occur, and it is
understood that the damping material 2 prevents disturbance of the sound field. [Effects of the
Invention] As described above, according to the present invention, the following effects can be
obtained because the damping material is adhered to the surface of the water pressure resistant
film whose inside is an air chamber. First, since a water pressure resistant membrane that can
withstand high water pressure is used, the air chamber in the water pressure resistant shell is not
compressed, and it is possible to use it under high water pressure. In addition, sound pressure
reflection can be performed over the entire frequency band because reflection of incident sound
pressure is performed by the water pressure resistant film and the air chamber, whereby the
water pressure resistance shell has a plate thickness as in the conventional hard type. Since it is
not necessary to increase the thickness, it can be made lightweight, and the water pressure
resistant membrane has a large buoyancy in the water odor because it contains an air bubble,
and the weight in the water is thus further reduced, so the underwater structure It is very
advantageous as a thing. Furthermore, the resonance phenomenon of the water pressure
resistant film and the re-radiation of the sound pressure obliquely incident on the water pressure
resistant film can be suppressed or reduced by the damping material attached to the surface of
the water pressure resistant film. Since the disturbance of the wave receiving point of the
transducer and the like can be prevented and the stable directivity characteristic can be obtained,
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it exhibits an excellent function as a baffle of the transducer and the like in the sonar.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a front view showing an embodiment of a baffle for a sonar according to the present
invention, and FIG. 2 is a horizontal orientation of the receiver output when the embodiment is
used!
FIG. 3 is a graph showing characteristics, and FIG. 3 is a graph showing horizontal directivity
characteristics of a receiver output when only a water pressure resistant film is used. 1: Waterresistant film 2: Damping material 3: Transducer patent applicant Applicant Oki Electric Industry
Co., Ltd. Attorney Attorney Kimura Toru 2 Front view showing one embodiment of the present
invention @ 1 [m
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