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JPH11146476

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DESCRIPTION JPH11146476
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
vibration source for a transmitter suitable for use in an electroacoustic transducer for emitting a
sound wave into water.
[0002]
2. Description of the Related Art Generally, as an electroacoustic transducer, there is known one
provided with a vibration source for a transmitter having a piezoelectric vibrator made of, for
example, a zirconate-lead titanate piezoelectric material. For example, as shown in FIG. 6, a
piezoelectric vibrator 52 with a lead wire 51 having a relatively large piezoelectric constant (d33)
and Poisson's ratio is used as the piezoelectric vibrator of the vibration source for the wave
transmitter.
[0003]
In such a vibration source for a transmitter, when a voltage is applied to the piezoelectric
vibrator 52 from the lead wire 51, it extends in the longitudinal direction as shown by a two-dot
chain line in the figure and contracts in the lateral direction. For this reason, the vibration sound
having the phase opposite to the phase of the vibration sound radiated in the vertical direction of
the piezoelectric vibrator 52 is emitted to both sides, and the acoustic radiation efficiency is poor.
04-05-2019
1
[0004]
In addition, in such a vibration source for a transmitter, by providing a piezoelectric vibrator
having a piezoelectric constant (d31) and a Poisson's ratio relatively small, vibration sound of
opposite phase is hardly radiated to both sides of the piezoelectric vibrator. In this case, the
radiated sound in the vertical direction is also small, and the acoustic radiation efficiency is poor
as in the piezoelectric vibrator having a relatively large piezoelectric constant (d33) and Poisson's
ratio.
[0005]
Therefore, in order to obtain good acoustic radiation efficiency, a transmitter vibration source as
shown in FIGS. 7 (a), (b) and FIGS. 8 (a), (b) is conventionally employed.
The transmitter vibration source will be described with reference to FIG. First, the vibration
source for the transmission device shown in FIGS. 7A and 7B will be described. In the figure, the
vibration source for the transmission device indicated by reference numeral 61 includes the
piezoelectric vibrator 62 and the metal cover 63. The piezoelectric vibrator 62 is formed of a
cylindrical piezoelectric vibrator as a whole.
[0006]
The metal cover 63 is formed of a cylindrical body having inner flanges 63a and 63b at both
open end faces and opening in both axial directions, and is attached to the outer peripheral
surface of the piezoelectric vibrator 62. An air layer 64 for sound absorption is formed between
the inner peripheral surface of the metal cover 63 and the outer peripheral surface of the
piezoelectric vibrator 62, or a member for sound absorption (cut-off) such as cork (not shown) Is
filled.
[0007]
Next, the transmitter vibration source shown in FIGS. 8 (a) and 8 (b) will be described. In the
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figure, the transmitter vibration source indicated by reference numeral 71 is the transmitter
shown in FIGS. 7 (a) and 7 (b). As in the case of the vibration source 61 for wave, the
piezoelectric vibrator 72 and the metal cover 73 are provided. The piezoelectric vibrator 72 is
formed of a piezoelectric vibrator having a rectangular cross-sectional shape that is entirely long.
[0008]
The metal cover 73 is formed of two cover elements 73a and 73b having a U-shaped cross
section and having a front longitudinal longitudinal outside dimension, and the cover elements
73a and 73b are bonded to both sides of the piezoelectric vibrator 72. The horizontal dimensions
of the cover elements 73a and 73b are set to dimensions sufficiently smaller than the horizontal
dimensions of the piezoelectric vibrator 72, and the vertical dimensions thereof are set to the
same size as the vertical dimensions of the piezoelectric vibrator 72. Between each cover element
73a, 73b and the piezoelectric vibrator 72, an air layer 74 for sound absorption is formed, or a
member for sound absorption (cutoff) such as cork (not shown) is filled. There is.
[0009]
However, in the conventional vibration source for a wave transmitter, the air layers 64, 74 or the
sound absorbing member (shown in FIG. 2) are disposed between the metal covers 63, 73 and
the piezoelectric vibrators 62, 72. Because the structure is intervened, if the stress generated by
water pressure becomes large when used at a considerable depth position, the metal covers 63,
73 etc. will be damaged and the degree of freedom in water use will be reduced There was a
problem.
[0010]
In addition, since a single piezoelectric vibrator is used in a conventional vibration source for a
transmitter, vibration sound having an opposite phase from the piezoelectric vibrator is radiated
when the piezoelectric constant and Poisson's ratio are relatively large. On the other hand, when
the piezoelectric constant and Poisson's ratio are relatively small, only a small vibrational sound
is emitted from a predetermined vibration surface, and there is also a problem that good acoustic
radiation efficiency can not be obtained.
[0011]
The present invention has been made in view of such circumstances, and it is an object of the
present invention to provide a vibration source for a transmitter capable of obtaining freedom of
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use in water and obtaining good acoustic radiation efficiency.
[0012]
SUMMARY OF THE INVENTION In order to achieve the above object, the vibration source for a
transmitter according to claim 1 of the present invention is an electrical signal which is bonded
to each other inside and outside each other and which can be applied independently to each
other. Of the two piezoelectric vibrators having polarization directions perpendicular to each
other, and the main piezoelectric vibrator located on the inner side of the two piezoelectric
vibrators is the outer side. The piezoelectric vibrator has a larger piezoelectric constant and
Poisson's ratio than the sub-piezoelectric vibrator located in the above, and is formed of a
piezoelectric vibrator having a polarization direction in a direction perpendicular to the nonadhesive surface of the vibrator.
Therefore, when an electrical signal of the same phase is applied to the main and sub
piezoelectric vibrators to vibrate the main piezoelectric vibrator in a direction perpendicular to
the non-bonded surface of the vibrator, the main piezoelectric vibrator is a vibrator according to
Poisson's ratio. While contracting in the non-adhesive surface direction, the sub piezoelectric
vibrator expands so as to compensate for the contraction of the main piezoelectric vibrator, and
contraction of the main piezoelectric vibrator in the vibrator non-bonding surface direction is
apparently eliminated.
[0013]
The invention according to claim 2 is the vibration source for a transmitter according to claim 1,
wherein the main piezoelectric vibrator is formed by a cylindrical member, and the sub
piezoelectric vibrator is formed by a cylindrical member opened in both axial directions. is there.
Therefore, when an electrical signal in the same phase is applied to the main and sub
piezoelectric vibrators to vibrate the main piezoelectric vibrator in the vibrator axial direction,
the main piezoelectric vibrator contracts in the vibrator radial direction according to the
Poisson's ratio At the same time, the sub piezoelectric vibrator expands so as to compensate for
the contraction of the main piezoelectric vibrator, and the contraction in the vibrator radial
direction of the main piezoelectric vibrator is apparently eliminated.
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[0014]
According to a third aspect of the present invention, in the vibration source for a transmitter
according to the second aspect, the sub-piezoelectric vibrator comprises a large number of
vibrator elements arranged in parallel in the circumferential direction.
Therefore, when an electric signal of the same phase is applied to the main and sub piezoelectric
vibrators to vibrate each vibrator element in a direction perpendicular to the vibrator nonbonding surface, each vibrator element is a vibrator according to Poisson's ratio. While
contracting in the non-bonding surface direction, the sub piezoelectric vibrator expands so as to
compensate for the contraction of each transducer element, and the contraction in the transducer
non-bonding surface direction in each transducer element disappears apparently.
[0015]
The invention according to claim 4 is the vibration source for a transmitter according to claim 1,
wherein the main piezoelectric vibrator is formed by a single square member, and the sub
piezoelectric vibrator sandwiches the main piezoelectric vibrator. As a configuration formed by
Therefore, when an electrical signal of the same phase is applied to the main and sub
piezoelectric vibrators to vibrate the main piezoelectric vibrator in the vibrator thickness
direction, the main piezoelectric vibrator contracts in the vibrator width direction according to
the Poisson's ratio. At the same time, the sub piezoelectric vibrator expands so as to compensate
for the contraction of the main piezoelectric vibrator, and the contraction in the vibrator width
direction of the main piezoelectric vibrator apparently disappears.
[0016]
According to a fifth aspect of the present invention, in the vibration source for a transmitter
according to the fourth aspect, the main piezoelectric vibrator comprises a plurality of vibration
elements arranged in parallel in a direction perpendicular to the polarization direction. Therefore,
when an electric signal of the same phase is applied to the main and sub piezoelectric vibrators
to vibrate each transducer element in the polarization direction, each transducer element
contracts in the direction perpendicular to the polarization direction according to the Poisson's
ratio At the same time, the sub piezoelectric vibrator expands so as to compensate for the
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contraction of each vibrator element, and the contraction in the direction perpendicular to the
polarization direction in each vibrator element is apparently eliminated.
[0017]
The invention according to claim 6 is the vibration source for a transmitter according to any one
of claims 1 to 5, wherein each piezoelectric vibrator is a piezoelectric vibrator of an acoustic
transducer. Therefore, when an electrical signal of the same phase is applied to the main and sub
piezoelectric vibrators in the acoustic transducer to vibrate the main piezoelectric vibrator in a
direction perpendicular to the non-bonded surface of the vibrator, the main piezoelectric
vibration according to Poisson's ratio As the element contracts in the vibrator non-adhering
surface direction, the sub piezoelectric vibrator expands so as to compensate for the contraction
of the main piezoelectric vibrator, and the contraction in the vibrator non-bonding surface
direction of the main piezoelectric vibrator disappears apparently.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be
described below with reference to the drawings. 1 (a) and 1 (b) are an external perspective view
showing a usage example of the vibration source for a wave transmitter according to the first
embodiment of the present invention and its b-b local sectional view, and FIG. It is a sectional
view showing a vibration source for transmitters concerning an embodiment. In the figure, the
electroacoustic transducer indicated by reference numeral 1 includes a transmitter vibration
source 2, a baffle base 3, and a case 4. The transmitter vibration source 2 includes piezoelectric
vibrators 5 and 6 and lead wires 7 and 8.
[0019]
The piezoelectric vibrator 5 is formed of a cylindrical main piezoelectric vibrator and is bonded
to the upper surface of the baffle base 3. The entire piezoelectric vibrator 5 has a polarization
direction (direction of arrow a in FIG. 2) in the axial direction, and has a relatively large
piezoelectric constant (d33) and Poisson's ratio, for example, a zirconate-lead titanate
piezoelectric material. It is formed of a material ("N-6 material").
04-05-2019
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[0020]
The piezoelectric vibrator 6 is formed of a cylindrical sub piezoelectric vibrator that opens in
both axial directions, and is bonded to the upper surface of the baffle base 3 and the outer
peripheral surface of the piezoelectric vibrator 5. The entire piezoelectric vibrator 6 has a
polarization direction in the radial direction (direction of arrow b in FIG. 2) and has a
piezoelectric constant (d33) smaller than the piezoelectric constant of the piezoelectric vibrator 5
and Poisson's ratio and Poisson's ratio, for example It is formed of a lead titanate-based
piezoelectric material ("N-2200 material").
[0021]
The lead wires 7 consist of two lead wires and are connected to the upper and lower end surfaces
(axial end surfaces) of the piezoelectric vibrator 5. The lead wire 8 consists of two lead wires and
is connected to the inner and outer circumferential surfaces of the piezoelectric vibrator 6. As a
result, an electrical signal is applied to each of the piezoelectric vibrators 5 and 6 independently
from each of the lead wires 7 and 8.
[0022]
The baffle base 3 is entirely formed of a flat circular metal plate such as aluminum. Thereby,
downward radiation of the vibration noise from the transmitter vibration source 2 is blocked.
[0023]
The case 4 is disposed on the upper surface of the baffle base 3 and covered with the
piezoelectric vibrators 5 and 6 and is entirely formed of a headed cylindrical body made of a
synthetic resin such as urethane. Thereby, the water tightness of the inside of the case 4 is
maintained, and a part of both the piezoelectric vibrators 5 and 6 and the lead wires 7 and 8 is
protected.
[0024]
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Next, the operation of the piezoelectric vibrator at the time of acoustic radiation of the
electroacoustic transducer configured as described above will be described with reference to
FIGS. 3 (a) and 3 (b). FIGS. 3A and 3B are cross-sectional views showing the pre-vibration state
and the state during vibration of the piezoelectric vibrator in the vibration source for a wave
transmitter according to the first embodiment of the present invention. That is, from the state
before vibration shown in FIG. 6A, an electric signal having the same longitudinal mode vibration
phase is applied to the piezoelectric vibrators 5 and 6 so that the piezoelectric vibrator 5 is
perpendicular to the vibrator non-bonding surface ( When the piezoelectric vibrator 6 is vibrated
in the axial direction and the piezoelectric vibrator 6 is vibrated in the vibrator non-adhering
surface direction (radial direction), the piezoelectric vibrator 5 does not vibrate as shown in FIG.
While shrinking from the radial dimension D1a to the radial dimension D1b in the bonding
surface direction (radial direction), the piezoelectric vibrator 6 stretches from the radial
dimension D2a to the radial dimension D2b so as to compensate for the contraction of the
piezoelectric vibrator 5 .
[0025]
At this time, since the voltage applied to each of the piezoelectric vibrators 5 and 6 is controlled,
the radial dimension (D1a + 2 × D2a) and the radial dimension (D1a + 2 × D2a) of the entire
piezoelectric vibrator (vibration source for transmitter) D1b + 2 × D2b) has the same dimension.
[0026]
In FIGS. 6A and 6B, the symbol D indicates the radial dimension of the vibration source 2 for the
wave transmitter (the radial dimension D1a of the piezoelectric vibrator 5 before vibration and
the radial dimension 2 of the piezoelectric vibrator 6 before vibration. A dimension obtained by
adding × D2a or a dimension obtained by adding the radial dimension D1b at vibration of the
piezoelectric vibrator 5 and the radial dimension 2 × D2b at vibration of the piezoelectric
vibrator 6 are shown.
[0027]
Therefore, in the present embodiment, since the radial contraction of the vibration source 2 for
the wave transmission device is apparently eliminated, the radial vibration of the vibration source
2 for the transmission wave can be suppressed to obtain good acoustic radiation efficiency.
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8
In this case, in order to suppress the radial vibration of the vibration source 2 for the wave
transmitter, the voltage and phase applied to each of the piezoelectric vibrators 5 and 6 are
controlled, but the radial dimension of the piezoelectric vibrator 5 is changed. It is also good.
[0028]
In addition, in the present embodiment, the cork and the like conventionally required to obtain
good acoustic radiation efficiency are not required, and therefore, it can be used even at a
considerably deep water depth, and the degree of freedom in use can be increased. it can.
[0029]
Furthermore, in the present embodiment, since the vibration in the transverse mode (radial
direction vibration) is reduced, the acoustic radiation surface becomes a uniform vibration
surface only on the piezoelectric vibrator 5 due to the baffle effect, and directivity on good
acoustic radiation You can get
[0030]
In the present embodiment, although the case where the piezoelectric vibrator 6 is formed of a
cylindrical body opened in both axial directions has been described, the same effect as that of the
embodiment can be obtained by using a large number of vibrator elements arranged in parallel in
the circumferential direction. .
[0031]
Next, a second embodiment of the present invention will be described using FIGS. 4 (a) and 4 (b).
FIGS. 4 (a) and 4 (b) are an external appearance perspective view and an bb cross-sectional view
showing a usage example of a vibration source for a wave transmitter according to a second
embodiment of the present invention.
In the figure, an electroacoustic transducer indicated by reference numeral 11 includes a
vibration source 12 for a wave transmitter, a baffle base 13 and a case 14.
The transmitter vibration source 12 includes piezoelectric vibrators 15 and 16 and lead wires 17
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9
and 18.
[0032]
The piezoelectric vibrator 15 is made of a square main piezoelectric vibrator, and is bonded to
the upper surface of the baffle table 13.
The entire piezoelectric vibrator 15 has a polarization direction in a direction perpendicular to
the vibrator non-adhering surface, and has a relatively large piezoelectric constant (d33) and
Poisson's ratio, for example, a zirconate-lead titanate piezoelectric material ("N-6 material") is
formed.
[0033]
The piezoelectric vibrator 16 is composed of two rectangular sub-piezoelectric vibrators, which
are bonded to the upper surface of the baffle base 13 and the side surfaces of the piezoelectric
vibrator 15 respectively. The entire piezoelectric vibrator 6 has a polarization direction in the
direction of non-adherence of the vibrator and has a piezoelectric constant (d31) smaller than the
piezoelectric constant of the piezoelectric vibrator 15 and the Poisson's ratio and a Poisson's
ratio. Of the piezoelectric material ("N-2200 material").
[0034]
The lead wires 17 consist of two lead wires and are connected to the upper and lower end
surfaces of the piezoelectric vibrator 15. The lead wires 18 consist of two pairs of lead wires and
are connected to the inner and outer side surfaces of each piezoelectric vibrator 16. As a result,
electrical signals are applied to the piezoelectric vibrators 15 and 16 independently from the lead
wires 17 and 18, respectively.
[0035]
The baffle base 13 is entirely formed of a flat square metal plate such as aluminum. Thereby,
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downward radiation of the vibration noise from the transmitter vibration source 12 is blocked.
[0036]
The case 14 is disposed on the upper surface of the baffle table 13 and is covered with the two
piezoelectric vibrators 15 and 16, and is entirely formed of a headed rectangular box made of a
synthetic resin such as urethane. Thereby, the water tightness of the inside of the case 14 is
maintained, and both the piezoelectric vibrators 15 and 16 and the lead wires 17 and 18 are
protected.
[0037]
In the electro-acoustic transducer configured as described above, since the contraction in the
vibrator non-bonding surface direction of the vibration source 12 for the transmitter is
apparently eliminated at the time of acoustic radiation, the vibration in the vibrator non-bonding
surface direction of the transmitter vibration source 12 is Similar to the first embodiment, it is
possible to suppress and obtain good sound radiation efficiency and to increase the degree of
freedom in use.
[0038]
Further, in the present embodiment, as in the first embodiment, since the vibration in the
transverse mode (vibration in the vibrator non-adhering surface direction) is reduced, it is
possible to obtain good directivity on acoustic radiation.
[0039]
In the present embodiment, although the case where the piezoelectric vibrator is formed of a
single piezoelectric vibrator has been described, the present invention is not limited to this, and
as a third embodiment, as shown in FIGS. 5 (a) and 5 (b). As shown, even when the piezoelectric
vibrator 21 includes a large number of vibrating elements 21a arranged in parallel in the
direction perpendicular to the polarization direction, the same effect as that of the embodiment
can be obtained.
[0040]
Further, it is needless to say that the material of the piezoelectric vibrator in the present
invention is not limited to the embodiment described above.
04-05-2019
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[0041]
As described above, according to the present invention, each of the two piezoelectric vibrators is
composed of piezoelectric vibrators having polarization directions perpendicular to each other.
Since the piezoelectric vibrator is formed by a piezoelectric vibrator having a larger piezoelectric
constant and Poisson's ratio than the sub-piezoelectric vibrator positioned and having a
polarization direction in a direction perpendicular to the non-bonded surface of the vibrator,
When an electrical signal of a phase is applied to vibrate the main piezoelectric vibrator in a
direction perpendicular to the vibrator non-bonding surface, the main piezoelectric vibrator
contracts in the vibrator non-bonding surface direction according to Poisson's ratio, and The
vibrator extends so as to compensate for the contraction of the main piezoelectric vibrator, and
the contraction of the main piezoelectric vibrator in the direction of the non-adhering surface of
the main piezoelectric vibrator apparently disappears.
[0042]
Therefore, vibration in the vibrator non-adhering surface direction of the piezoelectric vibrator
can be suppressed to obtain good acoustic radiation efficiency.
[0043]
Moreover, since cork etc. which were conventionally required in order to obtain a good sound
radiation efficiency become unnecessary, it can be used even at a considerably deep water depth,
and the degree of freedom in use can be increased.
[0044]
Furthermore, the ability to suppress vibration in the transducer non-adhering surface direction
means that the acoustic radiation surface becomes a uniform vibration surface due to the baffle
effect, and good directivity on acoustic radiation can also be obtained.
[0045]
Brief description of the drawings
[0046]
FIGS. 1 (a) and 1 (b) are an external appearance perspective view showing a usage example of a
vibration source for a wave transmitter according to a first embodiment of the present invention
and a partial cross-sectional view thereof at b-b.
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12
[0047]
2 is a cross-sectional view showing a vibration source for a transmitter according to the first
embodiment of the present invention.
[0048]
FIGS. 3A and 3B are cross-sectional views showing the pre-vibration state and the vibration state
of the piezoelectric vibrator in the vibration source for a wave transmitter according to the first
embodiment of the present invention.
[0049]
FIGS. 4 (a) and 4 (b) are an external appearance perspective view and an bb cross-sectional view
showing a usage example of a vibration source for a wave transmitter according to a second
embodiment of the present invention.
[0050]
FIGS. 5 (a) and 5 (b) are an external appearance perspective view and an bb cross-sectional view
showing an example of use of a vibration source for a transmitter according to a third
embodiment of the present invention.
[0051]
6 is a cross-sectional view shown to explain the operation at the time of voltage application in the
piezoelectric vibrator.
[0052]
FIGS. 7A and 7B are an external perspective view and a b-b cross-sectional view showing a
conventional vibration source for a transmitter (1).
[0053]
FIGS. 8 (a) and 8 (b) are an external perspective view and a b-b cross-sectional view showing a
conventional vibration source (2) for a transmitter.
[0054]
Explanation of sign
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[0055]
1 electroacoustic transducer 2 vibration source for transmitter 3 baffle base 4 case 5, 6
piezoelectric vibrator 7, 8 lead wire
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