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JP2007315791

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DESCRIPTION JP2007315791
PROBLEM TO BE SOLVED: To provide an underwater vessel using an underwater ultrasonic wave
utilizing apparatus including an ultrasonic transducer attached to the inner side of a ship bottom,
etc., in which the radiation intensity, the receiving sensitivity and the directional characteristic of
the ultrasonic wave radiated into the water are good. To provide a vessel with an ultrasonic wave
utilization device. SOLUTION: In a boat 10 with a fish finder, an ultrasonic transducer 6 is fixed
to a metal ship bottom portion 3 of the boat 1. The ultrasonic transducer 6 is stacked on the
piezoelectric element 61 with the piezoelectric element 61 vibrating in the thickness direction by
driving and the piezoelectric element 61 via the buffer body 63, and is in contact with the inner
surface 3B and has a columnar portion having many metal columnar portions 62C. Containing
the aluminum matching body 62, the wavelength of the ultrasonic vibration propagating through
the bottom of the metal ship is λb, the thickness of the bottom of the metal vessel is tb, the
wavelength of the ultrasonic vibration propagating through the aluminum matching body 62 is
λs, the wavelength matching When the thickness of the body is ts, 1 / 2-1 / 10 ≦ tb / λb + ts /
λs ≦ 1/2 + 1/10 is satisfied. [Selected figure] Figure 2
Underwater ultrasonic wave using vessel, underwater ultrasonic wave utilizing apparatus,
ultrasonic transducer used therefor, and wavelength matching body
[0001]
The present invention is a ship equipped with an underwater ultrasonic wave utilizing device
such as a fish finder and an underwater sounding device, a ship equipped with an underwater
ultrasonic wave utilizing device, an underwater ultrasonic wave utilizing device, an ultrasonic
transducer used therefor, and a wavelength matching body used therefor About.
04-05-2019
1
[0002]
Conventionally, underwater ultrasonic waves are used in underwater ultrasonic wave utilization
devices such as fish finders and underwater ultrasonic wave searchers.
In such an underwater ultrasonic wave utilization apparatus, when attaching an ultrasonic
transducer that emits ultrasonic waves to a ship or a case, a through hole is bored using a
member or the bottom of the ship to fix it to the outboard or the case, or be submerged The
method of letting In addition, methods such as an inner hull method or bonding an ultrasonic
transducer to the inner side surface of the bottom of the ship or the inner surface of the case are
also adopted.
[0003]
Among them, the method of bonding the ultrasonic transducer to the inner surface of the bottom
of the ship and the inner surface of the case does not send the ultrasonic transducer to the
outside (outside), so it is not easily affected by air bubbles even while the ship is running. It has
the advantage of being less prone to failure due to collisions with rocks or other obstacles.
[0004]
However, the method of bonding the ultrasonic transducer to the inner surface of the bottom of
the ship and the inner surface of the case radiates ultrasonic waves into the water through the
ship bottom and the case, so the loss is large and the same ultrasonic transducer is directly
immersed in the water. As compared with the case where it uses, the intensity of the ultrasonic
wave emitted in water falls, and the receiving sensitivity of an ultrasonic wave also falls.
Furthermore, the intensity of the side lobes tends to increase, and the directivity angle of the
main beam also tends to increase.
[0005]
The present invention has been made in view of the above problems, and it is an object of the
present invention to provide a ship equipped with an underwater ultrasonic wave utilization
04-05-2019
2
apparatus including an ultrasonic transducer attached to the inner side of a ship bottom, etc. It is
an object of the present invention to provide a ship with an underwater ultrasonic wave
utilization device having good strength, receiving sensitivity, and directional characteristics. In
addition, in the underwater ultrasonic wave utilization device which attaches the ultrasonic
transducer to the ship or the case, to provide the underwater ultrasonic wave utilization device
which makes the radiation intensity, the receiving sensitivity, and the directivity characteristic of
the ultrasonic wave radiated in water good. With the goal. Still another object of the present
invention is to provide an ultrasonic transducer used in the underwater ultrasonic wave
utilization apparatus, and a wavelength matching body used in the ultrasonic transducer.
[0006]
The solution is provided with an underwater ultrasonic wave utilization device including an
underwater ultrasonic wave utilization device including an ultrasonic transducer attached to the
inner side surface of the metal ship bottom portion at least a part of the ship bottom is made of
metal and is mounted on the inner surface of the metal ship bottom portion. The ultrasonic
transducer is a vibration element which ultrasonically vibrates in a predetermined vibration
direction at a predetermined frequency, and a wavelength matching body whose thickness
direction is the predetermined vibration direction, and the vibration element is the abovementioned vibration element. A wavelength matching body stacked in a predetermined vibration
direction directly or indirectly, in contact with the inner side of the ship, and having a
predetermined thickness for wavelength matching, the wavelength matching body including the
predetermined vibration in the wavelength matching body A plurality of metal columns or metal
columns each having an axis extending in the predetermined vibration direction at least partially
in the direction, and provided with a plurality of pillars separated from each other; Assuming that
the wavelength of ultrasonic vibration of wavenumber is λb, the thickness of the bottom of the
metal ship is tb, the wavelength of ultrasonic vibration of the predetermined frequency
propagating through the wavelength matching body is λs, and the thickness of the wavelength
matching body is ts. It is comprised so that a following formula (1) may be satisfy | filled, 1 / 2-1
/ 10 <= tb / lambdab + ts / lambdas <= 1/2 + 1/10 .. Formula (1) It is a ship with an underwater
ultrasonic wave utilization apparatus.
[0007]
The ship equipped with the underwater ultrasonic wave utilization device of the present
invention is provided with a wavelength matching body whose thickness direction is the
predetermined vibration direction of the vibrating element, and the metal ship bottom portion
and the wavelength matching body satisfy the relation of equation (1).
04-05-2019
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Specifically, the thickness tb of the metal ship bottom and the thickness ts of the wavelength
matching body are adjusted to tb / λb + ts / λs = 1/2 or a range sufficiently close to this (within
± 1/10) . That is, when the metal ship bottom portion and the wavelength matching body are
viewed in their thickness direction, the ultrasonic vibration generated in them is combined so as
to be approximately half the wavelength of the ultrasonic vibration. For this reason, it is possible
to suppress the loss and unnecessary reflection and efficiently radiate the ultrasonic waves from
the bottom of the metal ship to the outside (in water) while arranging the ultrasonic transducer
in the ship. Moreover, the ultrasonic wave which injects from water can be efficiently transmitted
to a vibration element. In addition, the directivity characteristic is improved, and the occurrence
of side lobes can be suppressed. Thus, it is possible to make a vessel with an underwater
ultrasonic wave utilization device having good ultrasonic wave radiation characteristics and wave
reception characteristics.
[0008]
In particular, in the ship of the present invention, the wavelength matching body of the ultrasonic
transducer is provided with a multi-column portion at least in part in a predetermined vibration
direction. In this multi-column portion, a large number of metal columns or metal columns
having an axis extending in a predetermined vibration direction are disposed apart from one
another. Therefore, each metal column has a radial dimension smaller than the radial dimension
of the entire wavelength matching body. In addition, ultrasonic vibration whose thickness
direction is a predetermined vibration direction is given to the wavelength matching body from
the vibration element. Accordingly, the ultrasonic vibration in the predetermined vibration
direction of the vibration element is transmitted along the axis of the metal column (or metal
column). In the metal column, with the transmission of the ultrasonic vibration, vibration (radial
vibration) is induced also in the radial direction perpendicular to the axis. However, in general,
radial vibrations tend to be less likely to be induced when the diameter of the medium (in this
case the metal column) is small. Therefore, for example, the induction of radial vibration is
suppressed as compared to a wavelength matching body having no multi-pillar portion
(therefore, the radial dimension is large because the whole is integrated). Thus, ultrasonic
vibration in a predetermined vibration direction of the vibration element is more efficiently
transmitted to the bottom of the metal ship through each metal column and vibrates the bottom
of the metal ship in the thickness direction. Thus, ultrasonic waves can be emitted efficiently. On
the other hand, generation of vibration in a form different from vibration in the thickness
direction, such as radial vibration of the wavelength matching body, can be suppressed, so
ultrasonic radiation in a direction different from the front can be suppressed, and the directivity
angle can be reduced. The occurrence of side lobes can also be suppressed. Moreover, not only
the characteristics at the time of radiation of the ultrasonic wave, but also the wave receiving
04-05-2019
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sensitivity is improved, the unnecessary ultrasonic wave incident from an angle shifted from the
front is suppressed from being transmitted to the vibration element through the wavelength
matching body. Noise can also be suppressed.
[0009]
In addition, as an underwater ultrasonic wave utilization device, an ultrasonic wave is emitted
into the water, such as a fish finder which detects a fish school in water, and an underwater
ultrasonic sounding device which examines the shape, depth, etc. of the water bottom such as the
seabed or lake bottom. , Equipment that receives ultrasonic waves from the water or emits
ultrasonic waves into the water and ultrasonic waves from the water to obtain information on the
water or the bottom of the water, as well as ultrasonic waves. Devices that use ultrasound in
water, such as underwater communication. In addition, as a ship body used for a ship with an
underwater ultrasonic wave utilization device, at least a part of the ship bottom is a metal ship
bottom part, and any ship in which an ultrasonic transducer is attached to this metal ship bottom
part may be used. It is also possible to use a ship that is entirely made of metal, or a ship that is
entirely made of metal, such as an aluminum ship.
[0010]
Further, the material of the metal forming the bottom metal part may be appropriately selected
according to the application of the ship, and it is preferable to select a metal capable of
transmitting ultrasonic waves with low loss. For example, aluminum and aluminum alloys such as
duralumin can be mentioned. In addition, carbon steel, steel such as stainless steel, titanium alloy
and the like can be mentioned. Further, as the vibrating element, any vibrating element can be
used as long as it can appropriately excite ultrasonic waves radiated into water. For example,
there are vibration elements such as piezoelectric elements, electrostrictive elements, and
magnetostrictive elements that can generate ultrasonic vibration of a predetermined frequency
by electric drive. Furthermore, when using a piezoelectric element, use a piezoelectric element
formed of a disc-like or square-plate-like piezoelectric ceramic polarized in the thickness
direction, or a bolt-clamped Langevin type vibration element using a ring-like piezoelectric
element. You can also.
[0011]
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In addition, the wavelength matching body has a multi-column portion in which a large number
of metal columns or metal columns are located at least in part in a predetermined vibration
direction (thickness direction). That is, specifically, the entire wavelength matching body is
formed of a collection of metal columns in which a large number of metal columns are arranged
in the direction orthogonal to the thickness direction, or a metal column is implanted on one
surface side of a metal flat plate , One in which many metal columns are bulged on one side of
the flat part, many metal columns are sandwiched by flat plates, or many metal columns are
integrally interposed between two flat parts. The thing which was made to do is mentioned.
Moreover, the wavelength matching body has a thickness (dimension in a predetermined
vibration direction) which satisfies the above-mentioned equation (1) or the equation (2)
described later.
[0012]
Further, among the wavelength matching bodies, as a form of the multi-pillar part, it is sufficient
if the axes of a large number of metal pillars (metal columnar parts) extend in the predetermined
vibration direction and are arranged apart from each other. Therefore, as a group of metal
columns (metal column parts), each of a polygonal column group such as a triangular column
group, a quadrangular column group, a hexagonal column group, a cylinder group, a concentric
ring group, and a concentric ring group is divided into plurals in the circumferential direction.
And mixtures of these as appropriate. Furthermore, in the case where the wavelength matching
body has a metal flat plate in addition to the metal column, or in the case where the wavelength
flat body has a metal flat portion integral with the metal columnar portion, the metal column or
the thickness ts of the wavelength matching body (whole) The dimension in the thickness
direction (the dimension in the axial direction) of the metal columnar portion may be at least 50%
or more, preferably 75% or more. As described above, the metal column or the metal column
portion suppresses radial vibration. Therefore, by increasing the ratio of this portion to the
wavelength matching body in the thickness direction, the effect of suppressing radial vibration
can be obtained as the entire wavelength matching body.
[0013]
Furthermore, the bonding surface of the wavelength matching body (for example, the end face of
the metal column or the metal column, the flat plate or the other side of the flat plate) and the
metal boat bottom or the metal water contact are mutually bonded by an adhesive without any
gap. Is preferred. In the wavelength matching body, it is preferable to flatten the end face of the
metal column or metal columnar portion to be the bonding surface, the flat surface of the flat
04-05-2019
6
plate or the other bonding surface of the flat portion by lapping or the like. Similarly, it is
preferable that appropriate surface finishing such as lapping or sandpaper be performed on at
least a portion of the inner surface of the metal ship bottom and the inner surface of the metal
water contact portion to be joined to the wavelength matching body. .
[0014]
Furthermore, in the vessel with the above-described underwater ultrasonic wave utilization
device, the multi-column portion of the wavelength matching body is a vessel with the
underwater ultrasonic wave utilization device formed by filling resin between the metal columns
or the metal pillars. It is good to assume.
[0015]
In a fish finder or an underwater exploration device, ultrasonic waves are emitted into water, and
then the presence or absence of a fish school or the water depth is detected by receiving
ultrasonic waves reflected back to the fish school or the bottom of the water.
In this case, in order to be able to appropriately detect from the shallow part to the deep part of
the water depth, it is necessary to be able to receive ultrasonic waves promptly after emitting
ultrasonic waves into water. Specifically, it is required to shorten the reverberation period of a
vibrating element (ultrasonic transducer) that emits ultrasonic waves by causing ultrasonic
vibration. Also, to make a so-called highly directional underwater ultrasonic wave utilization
apparatus capable of concentrating and radiating ultrasonic waves toward a desired direction
and selectively receiving ultrasonic waves from a desired direction. It is required to suppress the
side lobes.
[0016]
On the other hand, in the underwater ultrasonic wave utilizing apparatus according to the
present invention, in the multi-column portion of the wavelength matching body of the ultrasonic
transducer, the space between the metal columns or metal columns disposed apart from each
other is made of resin. It is filling. Since the resin is filled between the metal columns or metal
columns in this way, ultrasonic vibration is generated by the vibration element, and ultrasonic
waves are emitted from the bottom of the metal ship, and then the drive of the vibration element
is performed. When stopped, the continuation of the reverberation oscillation of the wavelength
04-05-2019
7
matching body and the vibrating element is suppressed immediately. The resin filled in the multipillar portion is resistant to the reverberation vibration and causes losses, so it is considered that
the reverberation vibration is suppressed. Thus, the reverberation period can be shortened.
Furthermore, as described above, in the metal column or the metal column portion, the induction
of its own radial vibration is suppressed. Moreover, since the induced radial vibration is absorbed
by the filled resin, generation of vibrations other than vibration in the thickness direction of the
wavelength matching body (axial direction of the metal column) can be suppressed more
efficiently. Can. Therefore, directivity can be sharpened and side lobes can be suppressed.
[0017]
In addition to resin easiness of filling, weather resistance, water resistance and vibration
absorption characteristics, it is good to select as a resin to be filled between metal columns
(metal column parts) in the multi-column part, specifically, Choose a flexible resin. For example,
epoxy resin having flexibility, silicon resin, urethane resin, etc. may be mentioned.
[0018]
Furthermore, in the above-mentioned underwater ultrasonic wave utilizing apparatus, the metal
ship bottom portion is made of aluminum or aluminum alloy, and the wavelength matching body
is made of aluminum or aluminum alloy except for the portion made of resin. It is good with the
vessel with utilization device.
[0019]
Some vessels, such as pleasure boats, have their bottoms or hulls made of aluminum (or an alloy
thereof) such as aluminum die cast.
As described above, when the bottom of the metal ship is made of aluminum (or its alloy), the
wavelength matching body excludes the portion made of the resin filled between the metal
columns (metal columns) of the multi-columns. The portion is also made of the same aluminum
(or an alloy thereof) to transmit ultrasonic vibration in a predetermined vibration direction,
specifically, a metal portion such as a metal column (metal columnar portion) in the wavelength
matching body, and a metal The acoustic impedance with the bottom of the ship has a similar
value, and the reflection of ultrasonic waves at the interface between the two can be suppressed.
04-05-2019
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[0020]
In the wavelength matching body, the portion excluding the resin portion includes a metal
column, a metal column, a flat plate made of metal with which the metal column abuts, a flat
portion integrated with the metal column, etc. Is included.
[0021]
Furthermore, in the vessel with the underwater ultrasonic wave utilization device according to
any one of the above-described items, the ultrasonic wave vibrator includes an ultrasonic buffer
body made of rubber between the vibrating element and a wavelength matching body. It is good
if it is a vessel with a utilization device.
[0022]
In the ultrasonic transducer having a structure in which the vibration element and the
wavelength matching body are directly bonded to each other, adhesive peeling may occur at the
interface between the two.
On the other hand, in the underwater ultrasonic wave utilizing apparatus according to the
present invention, the ultrasonic transducer is used in which the mechanical coupling between
the vibration element and the wavelength matching body is relaxed by the interposition of the
buffer body.
By this, the problem that the vibrating element adhered to the buffer body is peeled off by the
vibration of the vibrating element is prevented, and it is possible to make the vessel with the
underwater ultrasonic wave utilizing apparatus with higher reliability.
[0023]
In addition, it is good to select the material which can relieve | moderate the mechanical coupling
of a vibration element and a wavelength matching body moderately as a buffer body, and,
specifically, the rubber-like elastic body which has appropriate hardness is mentioned. Examples
thereof include rubber materials such as CR rubber and NBR rubber, and epoxy resins having
rubbery elasticity. Further, in order to electrically insulate the vibration element from the
04-05-2019
9
wavelength matching body, it is preferable to use an insulating material, for example, an
insulating rubber, as the buffer body.
[0024]
Another solution is an underwater ultrasonic wave utilization apparatus for use in a ship in which
at least a part of the ship bottom is a metal ship bottom, the ultrasonic waves scheduled to be
attached to the inner side of the metal ship bottom. The ultrasonic transducer is a vibration
element which ultrasonically vibrates in a predetermined vibration direction at a predetermined
frequency, and a wavelength matching body whose thickness direction is the predetermined
vibration direction, and the vibration element is the vibration element. A wavelength matching
body stacked in a predetermined vibration direction directly or indirectly, in contact with the
inner side of the ship, and having a predetermined thickness for wavelength matching, the
wavelength matching body including the predetermined vibration in the wavelength matching
body The predetermined circumference of the metal boat bottom portion is provided with a
multi-column portion in which a plurality of metal columns or metal columns having an axis
extending in the predetermined vibration direction are arranged apart from each other in at least
a part of the direction. When the wavelength of ultrasonic vibration of the number is λb, the
thickness of the bottom of the metal ship is tb, the wavelength of ultrasonic vibration of the
predetermined frequency transmitted through the wavelength matching body is λs, and the
thickness of the wavelength matching body is ts And 1 / 2-1 / 10 ≦ tb / λb + ts / λs ≦ 1/2 +
1/10 having a thickness ts satisfying the following formula (1).
[0025]
In the underwater ultrasonic wave utilization apparatus of the present invention, the ultrasonic
transducer is provided with a wavelength matching body whose thickness direction is the
predetermined vibration direction of the vibrating element, and the thickness ts of the
wavelength matching body and the ultrasonic transducer The thickness tb of the metal bottom
portion of the bottom of the ship to which is attached is set to satisfy the equation (1).
Specifically, the thickness tb of the metal ship bottom and the thickness ts of the wavelength
matching body are adjusted to tb / λb + ts / λs = 1/2 or a range sufficiently close to this (within
± 1/10) . That is, when the metal ship bottom portion and the wavelength matching body are
viewed in their thickness direction, the ultrasonic vibrations generated in these are combined so
as to have a thickness that is approximately half the wavelength of the ultrasonic vibration.
Therefore, by attaching the ultrasonic transducer to the bottom of the metal ship, loss and
unnecessary reflection can be suppressed while the ultrasonic transducer is disposed in the ship,
04-05-2019
10
and the ultrasonic waves can be efficiently outboard from the metal bottom Can be emitted).
Also, ultrasonic waves incident from water can be efficiently transmitted to the vibrating element.
In addition, the directivity characteristic is improved, and the occurrence of side lobes can be
suppressed. Thus, by using the underwater ultrasonic wave utilization device of the present
invention, it is possible to construct a ship equipped with the underwater ultrasonic wave
utilization device having good ultrasonic wave radiation characteristics and wave reception
characteristics.
[0026]
In particular, in the underwater ultrasonic wave utilization apparatus of the present invention,
the wavelength matching body of the ultrasonic transducer is provided with a multi-pillar portion
at least in part in a predetermined vibration direction. In this multi-column portion, a large
number of metal columns or metal columns having an axis extending in a predetermined
vibration direction are disposed apart from one another. Therefore, each metal column has a
radial dimension smaller than the radial dimension of the entire wavelength matching body. In
addition, ultrasonic vibration whose thickness direction is a predetermined vibration direction is
given to the wavelength matching body from the vibration element. Accordingly, the ultrasonic
vibration in the predetermined vibration direction of the vibration element is transmitted along
the axis of the metal column (or metal column). In the metal column, with the transmission of the
ultrasonic vibration, vibration (radial vibration) is induced also in the radial direction
perpendicular to the axis. However, in general, radial vibrations tend to be less likely to be
induced when the diameter of the medium (in this case the metal column) is small. Therefore, for
example, the induction of radial vibration is suppressed as compared to a wavelength matching
body having no multi-pillar portion (therefore, the radial dimension is large because the whole is
integrated). Thus, ultrasonic vibration in a predetermined vibration direction of the vibration
element is more efficiently transmitted to the bottom of the metal ship through each metal
column and vibrates the bottom of the metal ship in the thickness direction. Thus, ultrasonic
waves can be emitted efficiently. On the other hand, generation of vibration in a form different
from vibration in the thickness direction, such as radial vibration of the wavelength matching
body, can be suppressed, so ultrasonic radiation in a direction different from the front can be
suppressed, and the directivity angle can be reduced. The occurrence of side lobes can also be
suppressed. Moreover, not only the characteristics at the time of radiation of the ultrasonic wave,
but also the wave receiving sensitivity is improved, the unnecessary ultrasonic wave incident
from an angle shifted from the front is suppressed from being transmitted to the vibration
element through the wavelength matching body. Noise can also be suppressed.
[0027]
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11
Yet another solution is the underwater ultrasonic wave utilizing apparatus in which at least a part
of the water-contacting part in contact with the water at the time of use is a metal watercontacting part made of metal in the case surrounding itself. The ultrasonic transducer attached
to the inner side surface of the water portion, the ultrasonic transducer is in contact with the
inner side surface with the vibrating element ultrasonically vibrating in the predetermined
vibration direction at the predetermined frequency, and the predetermined thickness for
wavelength matching The wavelength matching body, wherein the wavelength matching body is
a metal column or a metal column having an axis extending in the predetermined vibration
direction at least in part in the predetermined vibration direction among the wavelength A
wavelength of ultrasonic vibration of the predetermined frequency transmitted through the metal
contact portion is λc, and a thickness of a portion of the metal contact portion through which
the ultrasonic vibration is transmitted. Tc, the above wavelength matching When the wavelength
of the ultrasonic vibration of the above-mentioned predetermined frequency that transmits the
light is λs, and the thickness of the wavelength matching body is ts, the thickness ts satisfying
the following formula (2) 1 / 2-1 / 10 ≦ tc / λc + ts / Λs ≦ 1⁄2 + 1/10 Equation (2) This is an
underwater ultrasonic wave utilizing apparatus.
[0028]
In the underwater ultrasonic wave utilization apparatus of the present invention, the ultrasonic
transducer is provided with a wavelength matching body whose thickness direction is the
predetermined vibration direction of the vibrating element, and the thickness ts of the
wavelength matching body and the ultrasonic transducer The thickness tc of the portion through
which the ultrasonic vibration is transmitted in the metal water contact portion of the case to
which is attached has the above-mentioned relationship that satisfies the equation (2).
Specifically, the thickness tb of the metal ship bottom and the thickness ts of the wavelength
matching body are adjusted within the range of tc / λc + ts / λs = 1/2 or sufficiently close
(within ± 1/10) There is. That is, when the metal water contact portion and the wavelength
matching body are viewed in the thickness direction thereof, the ultrasonic vibration generated
in them is combined so as to be approximately half the wavelength of the ultrasonic vibration.
Therefore, by attaching the ultrasonic transducer to the metal water contact portion, loss and
unnecessary reflection can be suppressed while arranging the ultrasonic transducer in the case,
and ultrasonic waves can be efficiently transmitted from the metal water contact portion to
water. Will be able to emit Also, ultrasonic waves incident from water can be efficiently
transmitted to the vibrating element. In addition, the directivity characteristic is improved, and
the occurrence of side lobes can be suppressed. Thus, the underwater ultrasonic wave utilization
device can be made to have good ultrasonic radiation characteristics and reception
04-05-2019
12
characteristics.
[0029]
In particular, in the underwater ultrasonic wave utilization apparatus of the present invention,
the wavelength matching body of the ultrasonic transducer is provided with a multi-pillar portion
at least in part in a predetermined vibration direction. In this multi-column portion, a large
number of metal columns or metal columns having an axis extending in a predetermined
vibration direction are disposed apart from one another. Therefore, each metal column has a
radial dimension smaller than the radial dimension of the entire wavelength matching body. In
addition, ultrasonic vibration whose thickness direction is a predetermined vibration direction is
given to the wavelength matching body from the vibration element. Accordingly, the ultrasonic
vibration in the predetermined vibration direction of the vibration element is transmitted along
the axis of the metal column (or metal column). In the metal column, with the transmission of the
ultrasonic vibration, vibration (radial vibration) is induced also in the radial direction
perpendicular to the axis. However, in general, radial vibrations tend to be less likely to be
induced when the diameter of the medium (in this case the metal column) is small. Therefore, for
example, the induction of radial vibration is suppressed as compared to a wavelength matching
body having no multi-pillar portion (therefore, the radial dimension is large because the whole is
integrated). Thus, ultrasonic vibration in a predetermined vibration direction of the vibration
element is more efficiently transmitted to the metal water contact portion through each metal
column, and the metal water contact portion is vibrated in the thickness direction. Ultrasonic
waves can be emitted efficiently toward the front. On the other hand, generation of vibration in a
form different from vibration in the thickness direction, such as radial vibration of the
wavelength matching body, can be suppressed, so ultrasonic radiation in a direction different
from the front can be suppressed, and the directivity angle can be reduced. The occurrence of
side lobes can also be suppressed. Moreover, not only the characteristics at the time of radiation
of the ultrasonic wave, but also the wave receiving sensitivity is improved, the unnecessary
ultrasonic wave incident from an angle shifted from the front is suppressed from being
transmitted to the vibration element through the wavelength matching body. Noise can also be
suppressed.
[0030]
In addition, as the case of the underwater ultrasonic wave utilization device, in addition to the
case where the ultrasonic transducer etc. is hermetically enclosed to make a waterproof
structure, the case where a part such as the upper part such as a boat shape or a bowl shape is
04-05-2019
13
open and not waterproof It can also be adopted. Moreover, as a material of the metal which
makes a metal water contact part, what is necessary is just to select suitably according to the use
of an underwater ultrasonic wave utilization apparatus, and it is preferable to select the metal in
which an ultrasonic wave is transmitted with low loss. For example, aluminum and aluminum
alloys such as duralumin can be mentioned. In addition, carbon steel, steel such as stainless steel,
titanium alloy and the like can be mentioned.
[0031]
Furthermore, in the underwater ultrasonic wave utilization device according to any one of the
above, the multi-columnar portion of the wavelength matching body may be a device that uses a
resin in the space between the metal pillars or the metal pillars. Good.
[0032]
In the underwater ultrasonic wave utilization device of the present invention, in the multi-column
portion of the wavelength matching body of the ultrasonic transducer, the space between the
metal columns or metal column portions arranged to be separated from each other is filled with
the resin.
As described above, since the resin is filled between the metal columns or the metal columnar
portions, ultrasonic vibration is generated by the vibration element, and ultrasonic waves are
emitted from the metal ship bottom portion or the metal water contact portion, When the drive
of the vibration element is stopped, the continuation of the reverberation vibration of the
wavelength matching body and the vibration element is suppressed quickly. The resin filled in
the multi-pillar portion is resistant to the reverberation vibration and causes losses, so it is
considered that the reverberation vibration is suppressed. Thus, the reverberation period can be
shortened. Furthermore, as described above, in the metal column or the metal column portion,
the induction of its own radial vibration is suppressed. Moreover, since the induced radial
vibration is absorbed by the filled resin, generation of vibrations other than vibration in the
thickness direction of the wavelength matching body (axial direction of the metal column) can be
suppressed more efficiently. Can. Therefore, directivity can be sharpened and side lobes can be
suppressed.
[0033]
Furthermore, in the underwater ultrasonic wave utilization device according to any one of the
above, the ultrasonic transducer is provided with a buffer body made of rubber between the
04-05-2019
14
vibration element and the wavelength matching body. Is preferred.
[0034]
In the ultrasonic transducer having a structure in which the vibration element is directly bonded
to the wavelength matching body, adhesive peeling may occur at the interface between the two.
On the other hand, in the underwater ultrasonic wave utilization apparatus of the present
invention, an ultrasonic transducer is used in which the mechanical coupling between the
vibration element and the wavelength matching body is relaxed by the interposition of the buffer
body. As a result, the problem in which the vibrating element bonded to the buffer body is peeled
off by the vibration of the vibrating element is prevented, and a more reliable underwater
ultrasonic wave utilizing apparatus can be obtained.
[0035]
Yet another solution is an ultrasonic transducer which is intended to be attached to the inner side
surface of the metal boat bottom portion in a ship in which at least a portion of the boat bottom
is a metal boat bottom portion made of metal, and has a predetermined frequency The vibration
element ultrasonically vibrates in a predetermined vibration direction, and the wavelength
matching body having the predetermined vibration direction as a thickness direction, wherein
the vibration element is stacked directly or indirectly in the predetermined vibration direction,
And a wavelength matching body having a predetermined thickness for performing wavelength
matching, the wavelength matching body including an axis extending in the predetermined
vibration direction at least partially in the predetermined vibration direction in the wavelength
matching body. A plurality of metal columns or metal columns each having a plurality of metal
columns each spaced apart from each other, and the wavelength of ultrasonic vibration of the
predetermined frequency transmitted to the bottom of the metal ship is λb, the metal Assuming
that the thickness of the bottom portion is tb, the wavelength of the ultrasonic vibration of the
predetermined frequency transmitted through the wavelength matching body is λs, and the
thickness of the wavelength matching body is ts, the thickness ts satisfies the following equation
(1) 1 / 2-1 / 10 ≦ tb / λb + ts / λs ≦ 1/2 + 1/10 Equation (1) This is an ultrasonic transducer.
[0036]
In the ultrasonic transducer of the present invention, the wavelength matching body is in a
04-05-2019
15
relationship satisfying the equation (1) with respect to the metal bottom portion of the bottom of
the boat to which the ultrasonic transducer is to be attached.
Specifically, the thickness tb of the bottom of the metal ship and the thickness ts of the
wavelength matching body are adjusted to tb / λb + ts / λs = 1/2 or a range sufficiently close to
this (within ± 1/10) . That is, when the metal ship bottom portion and the wavelength matching
body are viewed in their thickness direction, the ultrasonic vibrations generated in these are
combined so as to be approximately half the wavelength of the ultrasonic vibrations. Therefore,
by attaching the ultrasonic transducer to the bottom of the metal ship, loss and unnecessary
reflection are suppressed while the ultrasonic transducer is disposed in the ship, and the
ultrasonic waves are efficiently outboard from the bottom of the metal ship. In the water). Also,
ultrasonic waves incident from water can be efficiently transmitted to the vibrating element. In
addition, the directivity characteristic is improved, and the occurrence of side lobes can be
suppressed. Thus, it is possible to construct a ship equipped with an ultrasonic transducer having
good ultrasonic radiation characteristics and receiving characteristics.
[0037]
In particular, in the ultrasonic transducer of the present invention, the wavelength matching
body is provided with a multi-pillar portion at least in part in a predetermined vibration direction.
In this multi-column portion, a large number of metal columns or metal columns having an axis
extending in a predetermined vibration direction are disposed apart from one another. Therefore,
each metal column has a radial dimension smaller than the radial dimension of the entire
wavelength matching body. In addition, ultrasonic vibration whose thickness direction is a
predetermined vibration direction is given to the wavelength matching body from the vibration
element. Accordingly, the ultrasonic vibration in the predetermined vibration direction of the
vibration element is transmitted along the axis of the metal column (or metal column). In the
metal column, with the transmission of the ultrasonic vibration, vibration (radial vibration) is
induced also in the radial direction perpendicular to the axis. However, in general, radial
vibrations tend to be less likely to be induced when the diameter of the medium (in this case the
metal column) is small. Therefore, for example, the induction of radial vibration is suppressed as
compared to a wavelength matching body having no multi-pillar portion (therefore, the radial
dimension is large because the whole is integrated). Thus, ultrasonic vibration in a predetermined
vibration direction of the vibration element is more efficiently transmitted to the bottom of the
metal ship through each metal column and vibrates the bottom of the metal ship in the thickness
direction. Thus, ultrasonic waves can be emitted efficiently. On the other hand, generation of
vibration in a form different from vibration in the thickness direction, such as radial vibration of
the wavelength matching body, can be suppressed, so ultrasonic radiation in a direction different
04-05-2019
16
from the front can be suppressed, and the directivity angle can be reduced. The occurrence of
side lobes can also be suppressed. Moreover, not only the characteristics at the time of radiation
of the ultrasonic wave, but also the wave receiving sensitivity is improved, the unnecessary
ultrasonic wave incident from an angle shifted from the front is suppressed from being
transmitted to the vibration element through the wavelength matching body. Noise can also be
suppressed.
[0038]
Yet another solution is the underwater ultrasonic wave utilization apparatus according to the
present invention, in an underwater ultrasonic wave utilization apparatus in which at least a part
of the water contact portion in contact with water in use is a metal water contact portion made of
metal in a case surrounding itself. An ultrasonic transducer intended to be attached to an inner
surface, comprising: a vibrator element ultrasonically vibrating in a predetermined vibration
direction at a predetermined frequency; and a wavelength matching body having the
predetermined vibration direction as a thickness direction A wavelength matching body having a
predetermined thickness which is stacked directly or indirectly in the predetermined vibration
direction and is in contact with the inner surface to perform wavelength matching, and the
wavelength matching body includes the wavelength matching element The body is provided with
a multi-pillar portion in which a large number of metal columns or metal column portions having
an axis extending in the predetermined vibration direction are disposed apart from each other at
least in part in the predetermined vibration direction. The wavelength of the ultrasonic vibration
of the predetermined frequency which transmits the wavelength of the ultrasonic vibration of the
predetermined frequency transmitted through the wavelength matching body is λc, the
thickness of the portion of the metal contact portion where the ultrasonic vibration is
transmitted. λs, when the thickness of this wavelength matching body is ts, it has a thickness ts
satisfying the following formula (2) 1 / 2-1 / 10 ≦ tc / λc + ts / λs ≦ 1/2 + 1/10 (Formula (2)
) It is an ultrasonic transducer.
[0039]
In the ultrasonic transducer of the present invention, the wavelength matching body has a
relation satisfying the equation (2) with respect to the metal water contact portion of the case to
which the ultrasonic transducer is to be attached.
Specifically, the thickness tc of the portion through which the ultrasonic vibration is transmitted
in the metal water contact portion and the thickness ts of the wavelength matching body are tc /
λc + ts / λs = 1/2 or a range sufficiently close to this (± 1 Adjustment within 10). That is, when
04-05-2019
17
the metal water contact portion and the wavelength matching body are viewed in the thickness
direction thereof, the ultrasonic vibration generated in them is combined so as to be
approximately half the wavelength of the ultrasonic vibration. Therefore, by attaching the
ultrasonic transducer to the metal water contact portion, loss and unnecessary reflection are
suppressed while the ultrasonic transducer is disposed in the case, and the ultrasonic waves are
efficiently transmitted from the metal water contact portion. It can be emitted into water. Also,
ultrasonic waves incident from water can be efficiently transmitted to the vibrating element. In
addition, the directivity characteristic is improved, and the occurrence of side lobes can be
suppressed. Thus, the underwater ultrasonic wave utilization apparatus provided with the
ultrasonic transducer having the excellent ultrasonic radiation characteristics and the reception
characteristics can be configured.
[0040]
In particular, in the ultrasonic transducer of the present invention, the wavelength matching
body is provided with a multi-pillar portion at least in part in a predetermined vibration direction.
In this multi-column portion, a large number of metal columns or metal columns having an axis
extending in a predetermined vibration direction are disposed apart from one another. Therefore,
each metal column has a radial dimension smaller than the radial dimension of the entire
wavelength matching body. In addition, ultrasonic vibration whose thickness direction is a
predetermined vibration direction is given to the wavelength matching body from the vibration
element. Accordingly, the ultrasonic vibration in the predetermined vibration direction of the
vibration element is transmitted along the axis of the metal column (or metal column). In the
metal column, with the transmission of the ultrasonic vibration, vibration (radial vibration) is
induced also in the radial direction perpendicular to the axis. However, in general, radial
vibrations tend to be less likely to be induced when the diameter of the medium (in this case the
metal column) is small. Therefore, for example, the induction of radial vibration is suppressed as
compared to a wavelength matching body having no multi-pillar portion (therefore, the radial
dimension is large because the whole is integrated). Thus, ultrasonic vibration in a predetermined
vibration direction of the vibration element is more efficiently transmitted to the metal water
contact portion through each metal column, and the metal water contact portion is vibrated in
the thickness direction. Ultrasonic waves can be emitted efficiently toward the front. On the other
hand, generation of vibration in a form different from vibration in the thickness direction, such as
radial vibration of the wavelength matching body, can be suppressed, so ultrasonic radiation in a
direction different from the front can be suppressed, and the directivity angle can be reduced.
The occurrence of side lobes can also be suppressed. Moreover, not only the characteristics at
the time of radiation of the ultrasonic wave, but also the wave receiving sensitivity is improved,
the unnecessary ultrasonic wave incident from an angle shifted from the front is suppressed
from being transmitted to the vibration element through the wavelength matching body. Noise
04-05-2019
18
can also be suppressed.
[0041]
Furthermore, in the ultrasonic transducer according to any one of the above, the multi-columnar
portion of the wavelength matching body may be an ultrasonic transducer formed by filling a
resin between the metal columns or the metal columnar portions. .
[0042]
In the ultrasonic transducer according to the present invention, in the multi-pillar portion of the
wavelength matching body, the space between the metal pillars or the metal pillars disposed
apart from each other is filled with the resin.
As described above, since the resin is filled between the metal columns or the metal columnar
portions, ultrasonic vibration is generated by the vibration element, and ultrasonic waves are
emitted from the metal ship bottom portion or the metal water contact portion, When the drive
of the vibration element is stopped, the continuation of the reverberation vibration of the
wavelength matching body and the vibration element is suppressed quickly. The resin filled in
the multi-pillar portion is resistant to the reverberation vibration and causes losses, so it is
considered that the reverberation vibration is suppressed. Thus, the reverberation period can be
shortened. Furthermore, as described above, in the metal column or the metal column portion,
the induction of its own radial vibration is suppressed. Moreover, since the induced radial
vibration is absorbed by the filled resin, generation of vibrations other than vibration in the
thickness direction of the wavelength matching body (axial direction of the metal column) can be
suppressed more efficiently. Can. Therefore, directivity can be sharpened and side lobes can be
suppressed.
[0043]
Furthermore, it is preferable that the ultrasonic transducer according to any one of the abovedescribed embodiments is provided with a buffer body made of rubber between the vibrating
element and the wavelength matching body.
[0044]
04-05-2019
19
In the ultrasonic transducer having a structure in which the vibration element and the
wavelength matching body are directly bonded to each other, adhesive peeling may occur at the
interface between the two.
On the other hand, in the ultrasonic transducer of the present invention, the mechanical coupling
between the transducer element and the wavelength matching body is relaxed by the
interposition of the buffer body. As a result, the problem in which the vibrating element bonded
to the buffer body is peeled off by the vibration of the vibrating element is prevented, and a more
reliable underwater ultrasonic wave utilizing apparatus can be obtained.
[0045]
Yet another solution is an ultrasonic wave propagating through the radiation plane member
interposed between a vibrating element vibrating in a predetermined vibration direction at a
predetermined frequency and a radiation plane member having a radiation plane for radiating
ultrasonic waves in water. A wavelength matching body having a predetermined thickness for
performing wavelength matching, wherein at least a part of the wavelength matching body in the
predetermined vibration direction, metal pillars or metal columnar portions having axes
extending in the predetermined vibration direction are separated from each other Is a
wavelength matching body provided with a multi-pillar portion arranged in a large number.
[0046]
In particular, the wavelength matching body of the present invention is provided with a multipillar portion at least in part in a predetermined vibration direction.
In this multi-column portion, a large number of metal columns or metal columns having an axis
extending in a predetermined vibration direction are disposed apart from one another. Therefore,
each metal column has a radial dimension smaller than the radial dimension of the entire
wavelength matching body. Ultrasonic vibration whose thickness direction is a predetermined
vibration direction is given to the wavelength matching body from the vibration element.
Accordingly, the ultrasonic vibration in the predetermined vibration direction of the vibration
element is transmitted along the axis of the metal column (or metal column). In the metal column,
with the transmission of the ultrasonic vibration, vibration (radial vibration) is induced also in the
radial direction perpendicular to the axis. However, in general, radial vibrations tend to be less
likely to be induced when the diameter of the medium (in this case the metal column) is small.
Therefore, for example, the induction of radial vibration is suppressed as compared to a
04-05-2019
20
wavelength matching body having no multi-pillar portion (therefore, the radial dimension is large
because the whole is integrated). Thus, when the wavelength matching body is interposed
between the vibrating element and the radiation plane member, the ultrasonic vibration of the
vibrating element in a predetermined vibration direction can be generated by each wavelength
by performing wavelength matching of the ultrasonic wave propagating through the radiation
plane member. Since the radiation plane member is more efficiently transmitted to the radiation
plane member and vibrates in the thickness direction, ultrasonic waves can be efficiently radiated
from the radiation plane of the radiation plane member toward the front. On the other hand,
generation of vibration in a form different from vibration in the thickness direction, such as
radial vibration of the wavelength matching body, can be suppressed, so ultrasonic radiation in a
direction different from the front can be suppressed, and the directivity angle can be reduced.
The occurrence of side lobes can also be suppressed. Moreover, not only the characteristics at
the time of radiation of the ultrasonic wave, but also the wave receiving sensitivity is improved,
and unnecessary ultrasonic waves incident from an angle shifted from the front are suppressed
from being transmitted to the vibration element through the wavelength matching body. Noise
can also be suppressed.
[0047]
Furthermore, in the wavelength matching body, the multi-columnar portion may be a wavelength
matching body in which a resin is filled between the metal posts or the metal posts.
[0048]
The wavelength matching body of the present invention is filled with a resin between metal
columns or metal columns which are disposed apart from each other in the multi-column portion.
Since the resin is filled between the metal columns or metal columns in this way, this wavelength
matching body is incorporated into an ultrasonic transducer, and ultrasonic vibration is
generated by the vibration element, and a metal ship bottom or metal is produced. When the
drive of the vibration element is stopped after emitting ultrasonic waves from the water contact
portion, the continuation of the reverberation vibration of the wavelength matching body and the
vibration element is suppressed. The resin filled in the multi-pillar portion is resistant to the
reverberation vibration and causes losses, so it is considered that the reverberation vibration is
suppressed. Thus, the reverberation period can be shortened. Furthermore, as described above,
in the metal column or the metal column portion, the induction of its own radial vibration is
suppressed. Moreover, since the induced radial vibration is absorbed by the filled resin,
04-05-2019
21
generation of vibrations other than vibration in the thickness direction of the wavelength
matching body (axial direction of the metal column) can be suppressed more efficiently. Can.
Therefore, directivity can be sharpened and side lobes can be suppressed.
[0049]
Embodiments of the present invention will be described as Examples 1 and 2 with reference to
the drawings.
[0050]
A first embodiment of the present invention will be described with reference to FIGS.
The boat 10 with a fish finder of the first embodiment comprises a boat 1 and a fish finder 4
mounted on the boat 1. Among these, the boat 1 is a so-called aluminum vessel, and the entire
hull including the metal vessel bottom 3 which is a part of the vessel bottom 2 is made of an
aluminum alloy. The bottom 2 (metal bottom 3) is located below the water surface WS when the
boat 1 is floated on water.
[0051]
A fish finder 4 is mounted in the boat 1. The fish finder 4 includes an ultrasonic transducer 6 and
a main unit 5 that drives the ultrasonic transducer 6 and analyzes its output (received ultrasonic
wave output) to display the appearance in the water, the presence or absence of a fish school,
and the like. It is. The main device 5 includes a drive power supply 51 for driving the ultrasonic
transducer 6, and a display 52 for displaying the processed output of the ultrasonic transducer 6
as an image or data.
[0052]
On the other hand, as shown in FIG. 2, the ultrasonic transducer 6 is fixed to the inboard side
surface 3 </ b> B of the metal bottom portion 3 which is a part of the bottom 2. The thickness tb
of the metal boat bottom 3 in the portion to which the ultrasonic transducer 6 is fixed is tb = 6.0
mm, and the velocity of sound vb in the thickness direction is vb = 6455 m / s. The ultrasonic
04-05-2019
22
transducer 6 is disposed on the side of the disk-like (φ 40 × t 10 mm) piezoelectric element 61
and the front surface 61 F of the piezoelectric element 61, and has a diameter larger than that of
the piezoelectric element 61 and a substantially disc shape (φ 80 × t 15. An aluminum
matching body 62 of 0 mm) and a disk-like (φ 40 × t 5.0 mm) buffer body 63 having
substantially the same diameter as the piezoelectric element 61 and interposed between the
piezoelectric element 61 and the aluminum matching body 62 are provided.
[0053]
Among them, the piezoelectric element 61 is mainly composed of lead zirconate titanate, is
polarized in the thickness direction (vertical direction in FIG. 2, the direction along the axis AX),
and an electrode made of Ag on the front surface 61F and the back surface 61B. 61E1 and 61E2
are respectively formed. The electrodes 61E1 and 61E2 are connected to the main unit 5 via
unshown lead wires in the cable 66, and the piezoelectric element 61 is driven by the drive
circuit 51 at a predetermined drive frequency f (= 120 kHz). , Stretch (ultrasonic vibration) in the
thickness direction (axis AX direction).
[0054]
The aluminum matching body 62 includes a metal portion 62M made of an aluminum alloy
similar to that of the metal ship bottom portion 3 and a filled resin portion 62J, and as described
above, its thickness (dimension in the axis AX direction) ts = 15 It is .0 mm. Further, the speed of
sound velocity vs in the thickness direction of the aluminum matching body 62 is vs = 4940 m /
s. The aluminum matching body 62 is in close contact with the inboard side surface 3B of the
metal ship bottom portion 3 of the boat 1 via the adhesive layer AD at the front face 62F. The
aluminum alignment body 62 is ultrasonically vibrated in the thickness direction (axis AX
direction) by the ultrasonic vibration of the piezoelectric element 61, and is transmitted to the
metal ship bottom 3.
[0055]
As shown in FIG. 3, the metal portion 62M of the aluminum matching body 62 has a thickness
direction (ultrasonic wave) from the substantially flat metal flat plate portion 62P and the one
side surface (the lower side surface in FIG. 2A). The vibrator 6 is composed of a multi-columnar
portion 62D including a large number of metal columnar portions 62C extending in a direction
04-05-2019
23
along the axis AX. The flat metal portion 62P has a disk shape, and its thickness is tp. On the
other hand, the metal columnar portions 62C included in the multi-pillar portion 62D have a
rectangular shape with one side Wc having a dimension of td in the thickness direction and are
arranged in a grid shape through the slits 62L of the gap dimension Wj. There is. However, as
can be easily understood with reference to FIG. 2B, the planar shape of the metal columnar
portion 62C may be partially or largely cut away at the peripheral portion. In the first
embodiment, tp = 3.0 mm, Td = 12.0 mm, Wc = 7.0, and Wj = 1.0 mm. Further, in the multi-pillar
portion 62D, the space (slit 62L) between the metal columnar portions 62C is filled with a
flexible urethane resin to form the above-mentioned filled resin portion 62J. The function of the
aluminum matching body 62 will be described later.
[0056]
In addition, since the aluminum matching body 62 and the metal ship bottom portion 3 are made
of the same material, the acoustic impedances of the two are substantially equal, and reflection at
the interface between the two is less likely to occur. Further, it is preferable that the front face
62F of the aluminum aligning body 62 be leveled by lapping or the like so as to be in close
contact with the inner surface 3B of the bottom 3 of the metal ship. Similarly, it is preferable that
the inboard side surface 3B of the metal ship bottom portion 3 be smoothed with sandpaper,
lapping or the like.
[0057]
The buffer body 63 is made of insulating CR rubber, and is sandwiched between the front surface
61F of the piezoelectric element 61 and the back surface 62B of the aluminum matching body
62. Specifically, the piezoelectric element 61, the buffer body 63, and the aluminum matching
body 62 are bonded to each other by an adhesive (not shown). The buffer body 63 is interposed
between the piezoelectric element 61 and the aluminum matching body 62 to ease mechanical
coupling between the two. In particular, when the piezoelectric element 61 and the aluminum
matching body 62 are directly joined without the buffer body 63, vibration in the thickness
direction of the piezoelectric element 61 (expansion and contraction in the thickness direction)
and radial vibration (radial direction) Since the mode of the ultrasonic vibration excited by the
aluminum matching body 62 is not completely the same as in the case of (expansion), there is a
risk of causing “adhesion peeling” in which a crack occurs in the joint portion (adhesive agent)
between the two. Therefore, the buffer body 63 made of rubber is interposed to transmit the
ultrasonic vibration generated by the piezoelectric element 61 to the aluminum matching body
62 and to absorb the difference in the state of the vibration between the two.
04-05-2019
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[0058]
Thus, when the piezoelectric element 61 is driven by the drive circuit 51, the piezoelectric
element 61 expands and contracts (ultrasonic vibration) in the thickness direction (axial line AX
direction) at the vibration frequency f, and passes through the buffer 63 and the aluminum
matching body 62. The metal vessel bottom 3 can be ultrasonically vibrated and the ultrasonic
wave USR can be emitted from its radiation surface 3F into the water WT.
[0059]
A back member 64 surrounding the piezoelectric element 61 and the buffer body 63 is provided
at the rear (upper side in FIG. 2) and around the same.
The back member 64 is made of rubber and is used to prevent moisture and insulation of the
piezoelectric element 61 and absorb unnecessary vibration and reverberation vibration.
Furthermore, the ultrasonic transducer 6 includes a rubber float 65 made of rubber. The rubber
float 65 has a cylindrical portion 65H having a bottomed cylindrical shape surrounding the back
member 64 and the aluminum matching body 62, and a bush extending radially outward from
the cylindrical portion 65H and holding the cable 66 in a liquid tight manner. And a portion 65B.
Further, the inner peripheral surface 65I of the surrounding portion 65H and the peripheral
portion of the outer peripheral surface 65G of the aluminum matching body 62 and the back
surface 65B are in close contact (adhesion) in a liquid tight manner. An engaging flange 65T is
provided on the outer peripheral surface 65G of the aluminum alignment body 62 so that it is
difficult to come off from the surrounding portion 65H. Further, an internal space SP is formed
between the inner circumferential surface 65I of the surrounding portion 65H and the back
member 64 so that ultrasonic vibration is not transmitted to the surrounding portion 65H of the
rubber float 65 through the back member 64. It is so-called rimmed.
[0060]
Now, in the ultrasonic transducer 6 of the first embodiment, the aluminum matching body 62 is
interposed between the piezoelectric element 61 and the metal boat bottom portion 3 in relation
to the metal boat bottom portion 3 of the boat 1 and the thickness ts Is set as follows. That is, the
thickness (dimension in the axis AX direction) of the aluminum matching body 62 is ts, the
wavelength of ultrasonic vibration transmitting this is λs, the thickness (dimension in the axis
04-05-2019
25
AX direction) of the metal ship bottom 3 of the boat 1 is tb, When the wavelength of the sound
wave vibration is λb, the thickness ts of the aluminum matching body 62 is adjusted so as to
satisfy the following equation (1). 1 / 2-1 / 10 ≦ tb / λb + ts / λs ≦ 1/2 + 1/10 (1) The
wavelength λs is the vibration frequency f of the ultrasonic vibration to be transmitted, and the
speed of sound vs in the thickness direction of the aluminum matching body 62 From, it is
obtained by λs = vs / f. Similarly, the wavelength λb is obtained by λb = vb / f from the
vibration frequency f of the ultrasonic vibration to be transmitted and the speed of sound vb in
the thickness direction of the metal boat bottom 3.
[0061]
Specifically, in the boat 10 with a fish finder according to the first embodiment, f = 120 kHz, vs =
4940 m / s, and vb = 6445 m / s, so λs = 41.17 mm and λb = 53.79 mm. . また、
ts=15.0mm,tb=6.0mmである。 Therefore, tb / λb + ts / λs = 0.48, which is
understood to be included in the range of the equation (1). The sound velocity vb in the thickness
direction of the metal ship bottom 3 is actually measured by measuring the thickness of the
metal ship bottom 3 using an ultrasonic thickness gauge whose frequency is known, and
comparing with the thickness tb separately measured. Sound velocity vb of. In detail, the
thickness of the metal ship bottom 3 (a flat plate of an aluminum alloy of the same material and
the same thickness, actually, having a size of □ 200 × t6) is measured using a micrometer. On
the other hand, using an ultrasonic thickness meter (manufactured by Tokyo Keiki, UTM 100,
pulse reflection method, not shown), the thickness of the metal ship bottom 3 (actually the above
flat plate) is measured, and the speed of sound measurement switch of the ultrasonic thickness
meter The speed of sound was changed according to the above, and the speed of sound whose
thickness displayed by the ultrasonic thickness gauge matches the thickness actually measured
with a micrometer was taken as the speed of sound vb of the metal boat bottom 3. In addition,
since the measurement precision (display precision) of the thickness of an ultrasonic thickness
gage is 0.1 mm, width may arise in the speed of sound Vb obtained. In this case, the median
value of the obtained sound speed width is taken as the true sound speed Vb.
[0062]
Also, the speed of sound vs in the thickness direction of the aluminum matching body 62 can be
measured by measuring the mechanical resonance frequency in the thickness direction of the
aluminum matching body 62, and by measuring the thickness of the aluminum matching body
62. Calculated vs. Specifically, the aluminum matching body 62 is placed on a piezoelectric
ceramic for vibration excitation (not shown), and its vibration is measured by a laser Doppler
04-05-2019
26
vibrometer (not shown) from the direction directly opposite to the surface of the aluminum
matching body 6 The piezoelectric ceramic is vibrated. The vibration frequency is changed, and
the frequency (the mechanical resonance frequency in the thickness direction of the aluminum
matching body 62) fm at which the surface of the aluminum matching body 62 vibrates most is
measured. From the resonance frequency fm and the thickness t of the aluminum matching body
62 separately measured with a micrometer, the sound velocity Vs of the aluminum matching
body 62 is calculated according to Vs = fm × 2t.
[0063]
Formula (1) will be described. Equation (1) is obtained by setting the value of tb / λb + ts / λs
to ± 1/10 of the allowable width of tb / λb + ts / λs with tb / λb + ts / λs = 1/2 as a center.
In general, assuming that the thickness of an object is t and the wavelength of ultrasonic
vibration transmitted thereto is λ, t / λ is how many ultrasonic waves there are in the thickness
direction of this object. Show what you are doing. Therefore, in the equation (1), the waves of
ultrasonic vibration transmitted through the aluminum matching body 62 and the metal ship
bottom portion 3 are effectively included in these for half (1/2 wavelength). It shows that it is
preferable to set it as the dimensional relationship or the dimensional relationship approximate
to this.
[0064]
This is to radiate ultrasonic USR from the radiation surface 3F of the metal ship bottom 3 into the
water WT having a large difference in acoustic impedance, and an aluminum matching body 62
of appropriate thickness tb on the inboard side 3B of the metal ship bottom 3 Is added, and the
aluminum matching body 62 and the metal ship bottom portion 3 are combined to effectively
constitute a λ / 2 resonator. Thereby, it is considered that the ultrasonic wave USR can be
efficiently radiated from the radiation surface 3F into the water in the front (the direction of the
axis AX). Also, along with this, it is possible to suppress the occurrence of side lobes. As
described above, by combining the aluminum matching body 62 and the metal ship bottom
portion 3 to constitute an effective λ / 2 resonator, vibration in the thickness direction (the
direction of the axis AX) is selectively excited. It is considered that the generation of the vibration
in the direction of (the radial vibration) is suppressed. If the allowable width of tb / λb + ts / λs
is set to ± 1/10, within this range, the effective λ / 2 resonance can be achieved by combining
the aluminum matching body 62 and the metal ship bottom 3. While being able to be in a state
close to the body, ultrasonic USR can be efficiently emitted from the radiation surface 3 F into
water in the front (the direction of the axis AX), while the occurrence of side lobes can be
04-05-2019
27
sufficiently suppressed.
[0065]
Furthermore, in the first embodiment, the aluminum matching body 62 is not a simple disk
shape, but a multi-pillar portion 62D in which a large number of substantially square-pillarshaped metal columnar portions 62C are arranged in a grid shape in addition to the metal flat
plate portion 62P. In the form of In the multi-pillar portion 62D, ultrasonic vibration in the
direction along the axis AX generated by the piezoelectric element 61 can be transmitted to the
metal ship bottom portion 3 via the large number of metal columnar portions 62C.
[0066]
Furthermore, in the case where the aluminum matching body has a disk shape having no metal
columnar portion, when ultrasonic vibration in the direction along the axis AX is transmitted
from the piezoelectric element 61, the diameter thereof in the radial direction orthogonal to the
axis AX It can not be avoided that it causes radial vibration to expand and contract. On the other
hand, in the aluminum alignment body 62 of the first embodiment, the multi-pillar portion 62D
has a large number of metal columnar portions 62C. Each of the metal columnar portions 62C
has a planar dimension of one side Wc, and has a radial dimension sufficiently smaller than the
radial dimension of the aluminum matching body 62 (in the present embodiment, φ80 mm).
When ultrasonic vibration is transmitted through the respective metal columnar portions 62C,
the induced radial vibration is slight, and the metal columnar portions 62C are arranged with a
gap therebetween, and the filling resin portion 62J is interposed therebetween. It is arranged to
prevent radial vibrations from transmitting to each other. For this reason, in the aluminum
alignment body 62 of the first embodiment having the multi-pillar portion 62D, the induction of
the radial vibration is suppressed as compared with the disk-shaped aluminum alignment body.
Moreover, the thickness dimension td (td = 12.0 mm) of the metal columnar portion 62C is 80%
(td / ts = 80%) of the thickness dimension ts (ts = 15.0 mm) of the aluminum matching body 62.
Since it occupies, the radial vibration induced in the metal flat plate portion 62P is also
suppressed. Therefore, by using the aluminum matching body 62 of the first embodiment,
vibration (radial direction vibration) in a direction other than the thickness direction (axial line
AX direction) as compared to the case of using the disk-shaped aluminum matching body. Can be
efficiently radiated from the radiation surface 3F of the metal ship bottom 3 to which the
aluminum matching body 62 is bonded to the water in the front (the direction of the axis AX),
while the side lobes The occurrence can also be sufficiently suppressed.
04-05-2019
28
[0067]
Next, with respect to the boat with a fish finder according to Example 1 and Comparative
Examples 1 and 2 and Reference Example, the directivity characteristic, the transmission sound
pressure to the front (axis AX direction), the ultrasonic wave from the front (axis AX direction)
Received wave sensitivity was measured. However, it is difficult to measure the directivity
characteristics using the actual boat 1 because it requires a large-scale device, and instead of the
metal ship bottom 3, it is made of an aluminum alloy of the same material and has the same
thickness tb = 6. The working sample 1 in which the ultrasonic transducer 6 was adhered to the
center of a flat plate having a plane dimension of 200 × 200 mm having 0 mm was prepared,
and its directivity was measured. The same flat plate is used also for the ultrasonic transducer
according to Comparative Example 2 and Reference Example, and is used as Comparative Sample
2 and Reference Sample.
[0068]
Further, as described above, in the ultrasonic transducer 6 of the first embodiment
(implementation sample 1), the piezoelectric element 61 has a diameter of 40 mm and a
thickness of 10 mm. Further, the aluminum matching body 62 has a diameter of 80 mm and a
thickness of 15 mm. On the other hand, as Comparative Example 1, an ultrasonic transducer
provided with the piezoelectric element 61 and the buffer body 63 and not provided with the
aluminum matching body 62 is prepared, and directly thrown into water without being fixed to
the metal ship bottom 3 The directional characteristics were measured. Further, as Comparative
Example 2 (Comparative Sample 2), the ultrasonic transducer (specifically, the buffer body 63)
used in Comparative Example 1 was bonded to the above-mentioned flat plate (tb = 6.0 mm, 200
× 200 mm) Ones were made and their directivity characteristics were measured. Further, as a
reference example (reference sample), a disk-shaped aluminum alignment body (φ80 × t20)
which does not have the slit 62L in place of the aluminum alignment body 62 and does not have
the multi-pillar portion 62D (metal columnar portion 62C) Only the point which used was
different from the present Example 1 was created, and the directivity characteristic was
measured.
[0069]
The results for the directional characteristics are shown in FIG. 4 for Example 1 (implementation
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sample 1), in FIG. 5 for Comparative Example 1 and in FIG. 6 for Comparative Example 2
(Comparative Sample 2). The reference sample is shown in FIG. Further, FIG. 8 shows the
frequency characteristic of the transmission sound pressure, and FIG. 9 shows the frequency
characteristic of the reception sensitivity.
[0070]
As for the transmission sound pressure, the working sample 1 or the like in which the ultrasonic
transducer 6 is adhered to the above-mentioned flat plate is put into water, the axis AX of the
ultrasonic transducer 6 is kept horizontal at a water depth of 1 m, and the main unit 5 is used.
The ultrasonic wave transmitted through the water is detected by a receiver (ST-1004,
manufactured by Oki Electric Industry Co., Ltd., not shown) disposed at a position 1 m apart on
this axis. The output voltage of the wave receiver is observed with an oscilloscope (not shown).
The transmission sound pressure P is calculated by P (dB) = Vr−km. Here, P is the sound
pressure level of the transmission sound pressure (0 dB = 1 μPa), Vr is the output level of the
receiver (0 dB = 1 Vrms), and km is the receiver sensitivity (0 dB = 1 Vrms / μPa) of the receiver.
. The frequency characteristic of the transmission sound pressure shown in FIG. 6 is obtained by
measuring the transmission sound pressure at each frequency by changing the drive frequency
of the main unit 5.
[0071]
Further, the directivity characteristic measures the output voltage of the wave receiver in the
same manner as the measurement of the transmission sound pressure described above. At that
time, the state where the receiver is positioned on the axis AX of the ultrasonic transducer 6 (the
state where the receiver faces the flat plate) is an angle θ = 0 °, and the axis AX of the
ultrasonic transducer 6 is horizontal. While rotating in the horizontal direction, keep the angle of
rotation and measure the output voltage of the receiver at each angle. Furthermore, the relative
intensity G at each angle θ is calculated by G (dB) = 20 Log (Vθ / V0). Here, V0 is the output
voltage of the wave receiver at the angle θ = 0 °, and Vθ is the output voltage of the wave
receiver at the angle θ. Furthermore, the size of the angular range in which the relative intensity
G is within -6 dB is calculated as the directivity angle α.
[0072]
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30
Furthermore, the receiving sensitivity differs from the measurement of the above-mentioned
transmission sound pressure and directivity characteristics, and the working sample 1 or the like
in which the ultrasonic transducer 6 is adhered to a flat plate is put into water, and the ultrasonic
transducer 6 is Keep axis AX horizontal. In addition, an ultrasonic wave is generated by driving a
transmitter (ST-1004, manufactured by Oki Electric Industry Co., Ltd., not shown) disposed at a
position 1 m apart on this axis, and the ultrasonic wave transmitted through the water is an
ultrasonic wave oscillator. Receive at 6 and observe the output with an oscilloscope (not shown).
From the output voltage of the ultrasonic transducer 6 obtained by the oscilloscope, the
reception sensitivity S is calculated by S (dB) = VTD− (Vs + Ks). Here, S is the receiving
sensitivity of the ultrasonic transducer (0 dB = 1 Vrms / μPa), VTD is the level of the output
voltage of the ultrasonic transducer 6 (0 dB = 1 Vrms), and Ks is the transmitting intensity of the
transmitter (0 dB) = 1 μPa / Vrms · m). The frequency characteristic of the receiving sensitivity
shown in FIG. 7 is obtained by measuring the receiving sensitivity at each frequency by changing
the frequency of the ultrasonic wave by the transmitter.
[0073]
According to the graph of FIG. 4, in the working sample 1 using the ultrasonic transducer 6
according to the first embodiment, the directivity angle of the main beam (angle range to be −6
dB or more) α appearing near the angle 0 ° is It can be seen that α = 15 deg, and the peak of
the side lobe is suppressed to −20 dB or less compared to the main beam. On the other hand, in
the ultrasonic transducer according to Comparative Example 1, as shown in FIG. 5, the directivity
angle α of the main beam is α = 20 deg, and the peak of the side lobe is −13 dB or less
compared to the main beam. It turns out that it is suppressed. Further, in Comparative Sample 2
using the ultrasonic transducer according to Comparative Example 2, as shown in FIG. 6, the
directivity angle α of the main beam is α = 22 deg, and the peak of the side lobe is compared to
the main beam It can be seen that only -4 dB is suppressed. Furthermore, according to the graph
of FIG. 7, in the reference sample using the aluminum matching body according to the reference
example, the directivity angle (angle range of -6 dB or more) of the main beam appearing near
the angle 0 deg is α = 14 deg. It can be seen that the peak of the side lobe is suppressed to -17
dB or less compared to the main beam.
[0074]
Further, according to the frequency characteristics of the transmission sound pressure P of each
sample shown in FIG. 8, in the working sample 1 (marked with ア ル ミ) having the aluminum
matching body 62, the ultrasonic transducer 6 is disposed inside the boat 1 However, it can be
04-05-2019
31
seen that the transmission sound pressure P is about the same as that of Comparative Example 1
(◆: water throwing type). On the other hand, it is understood that the transmission sound
pressure P is reduced by about 10 dB in comparison sample 2 (.box-solid.) Having no aluminum
matching body 62 as compared to the working sample 1.
[0075]
Moreover, in the frequency characteristics of the receiving sensitivity S shown in FIG. 9, the
working sample 1 having the aluminum matching body 62 (▲ mark) has a receiving sensitivity
exceeding that of the comparative example 1 (◆ mark: underwater throwing type) in many
ranges. It is understood that S is obtained. On the other hand, it is understood that in the
comparative sample 2 (.box-solid.) Which does not have the aluminum matching body 62, the
wave receiving sensitivity S is also reduced by about 10 dB as compared to the working sample
1.
[0076]
From the comparison of Comparative Example 1 and Comparative Example 2 (comparative
sample 2) described above, it is possible to use an ordinary underwater (in Comparative Example
1 without an aluminum matching body) underwater ultrasonic transducer (Comparative Example
1) as a metal ship When it adheres to the bottom (comparative example 2), it turns out that
directivity angle alpha becomes large and a side lobe becomes large. In addition, it can be seen
that the transmission sound pressure (radiation intensity) P and the reception sensitivity S also
decrease significantly. In the case of Comparative Example 2 (Comparative Sample 2), there is no
aluminum matching body when the ultrasonic vibration generated by the piezoelectric element is
radiated from the bottom of the metal ship (flat plate in the case of Comparative Sample 2) into
water. In addition, mismatch occurs in the transmission of ultrasonic vibration from the
piezoelectric element to the bottom of the metal ship and transmission of ultrasonic vibration
from the bottom of the metal ship to the water. For this reason, reflection and loss occur at each
interface, and it is considered that after all, ultrasonic waves can not be emitted with sufficient
intensity into water. Moreover, not only vibration in the thickness direction of the piezoelectric
element but also radial vibration etc. are excited, and in addition to the intensity of the main
beam being reduced and the directivity angle α becoming larger, a large peak appears as a side
lobe Conceivable.
[0077]
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32
On the other hand, when the ultrasonic transducer 6 according to the first embodiment is used
(implementation sample 1), the directivity angle α is higher than that of the comparison example
2 (comparison sample 2) as well as the comparison example 1. It can be seen that a small, sharp
ultrasonic beam can be emitted into water, and side lobes can be sufficiently suppressed as
compared with Comparative Examples 1 and 2. Further, the transmission sound pressure
(radiation intensity) P of the ultrasonic wave USR is comparable to that of the underwater
throwing type ultrasonic transducer (comparative example 1), and the ultrasonic wave USR can
be emitted without loss. Thus, by using the ultrasonic transducer 6 provided with the aluminum
matching body 62, compared with the comparative example 2 (comparative sample 2) having no
aluminum matching body, the ultrasonic transducer 6 (boat having the same) is provided. The
radiation characteristics and directivity characteristics of ultrasonic USR in 10) can be greatly
improved. In addition, it is understood that the same or more characteristics can be obtained
compared to the underwater throwing type ultrasonic transducer (comparative example 1).
Furthermore, the wave receiving sensitivity for receiving ultrasonic waves USP from water can be
significantly improved as compared with Comparative Example 2 (Comparative Sample 2) having
no aluminum matching body, and the underwater vibration type ultrasonic vibration It can be
seen that characteristics equivalent to those of the child (comparative example 1) can be
obtained. Further, as compared with the reference sample, in the sample 1, an improvement of 3
dB was observed at the peak of the side lobe, and the effect of forming the metal columnar
portion 62C in the aluminum matching body 62 became clear.
[0078]
Subsequently, the fish finder of the boat equipped with the fish finder according to Example 1
and Comparative Example 2 was operated. The image appearing on the display 52 is shown in
FIG. In FIG. 10, (a) is an image obtained by the boat according to Example 1, and (b) is an image
obtained by the boat according to Comparative Example 2. Specifically, the ultrasonic
transducers according to Example 1 and Comparative Example 2 were attached to the same boat,
and the main device 5 was connected to drive them. More specifically, after the ultrasonic
transducer according to the first embodiment is driven to obtain an image (a), the main device 5
is immediately connected again and the ultrasonic transducer according to the comparative
example 2 is driven to obtain an image. I got (b). When comparing the both, when looking at the
fish school video considered to be the same fish school surrounded by “1” displayed in both
images, the signal strength is higher in the video (a) according to the first embodiment. Can be
seen. Further, it can be seen that the image (a) according to the first embodiment has a higher
signal strength even when looking at the bottom image displayed and enclosed by “2” in both
images. These are considered to be because the ultrasonic transducer 6 according to the first
04-05-2019
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embodiment has better radiation characteristics and reception characteristics of ultrasonic
waves.
[0079]
Furthermore, when looking at the vertical length of the image showing the reverberation
continuation time indicated by the arrow of “3” in both images, it can be understood that the
image (a) according to the first embodiment is shorter . From this, it can be seen that the
reverberation of the ultrasonic transducer 6 according to the first embodiment is canceled more
quickly after emitting the ultrasonic wave. This is because the multi-columnar portion 62D is
provided in the aluminum matching body 62 and a gap is provided between the metal columnar
portions 62C, so that reverberation hardly remains after the ultrasonic wave is radiated, and the
slits 62L between the metal columnar portions 62C. Since the filling resin portion 62J is
provided, it is considered that the reverberation vibration is absorbed by the filling resin portion
62J and the reverberation vibration is eliminated more rapidly.
[0080]
Also, looking at the lower part of the bottom image displayed as “4” in both images, in the
image according to Example 1, almost no signal is observed, while in the image according to
Comparative Example 2, noise continues It has been observed. This is because the fish finder
according to Comparative Example 2 receives unnecessary ultrasonic waves from each direction
that are not received in Example 1 due to the wide directional angle and the presence of large
side lobes. It is understood that it is because
[0081]
Thus, the boat 10 with a fish finder, the fish finder 4 and the ultrasonic transducer 6 according
to the first embodiment have good ultrasonic radiation characteristics and reception even while
the ultrasonic transducer 6 is disposed in the ship. It becomes a boat with a fish finder having
characteristics, a fish finder, and an ultrasonic transducer. Moreover, the aluminum matching
body 62 of the first embodiment can further improve the characteristics of the ultrasonic
transducer.
04-05-2019
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[0082]
Next, a second embodiment of the present invention will be described with reference to FIG. In
Example 1 mentioned above, the boat 10 with a fish finder which fixed the ultrasonic transducer
6 of the fish finder 4 to the metal ship bottom part 3 of the boat 1 was demonstrated. On the
other hand, the second embodiment relates to the underwater ultrasonic wave search device 140
used in the ship SH, and uses the ultrasonic transducer 6 having the same configuration as the
sixth embodiment. Therefore, different parts will be described, and descriptions of similar parts
will be omitted or simplified.
[0083]
The underwater ultrasonic probe 140 of the second embodiment comprises a main unit 150 and
a probe 160 including an ultrasonic transducer 6. Among them, the main body device 150 drives
the ultrasonic transducer 6 and analyzes its output (ultrasonic wave receiving output) to obtain
data on the underwater condition, the underwater condition (sea floor, lake bottom) and the like.
The main body device 150 includes a drive power supply 151 for driving the ultrasonic
transducer 6.
[0084]
On the other hand, the probe 160 has an ultrasonic transducer 6 and a case 161 which encloses
the same and seals it in a liquid tight manner. Among these, the ultrasonic transducer 6 is the
same as that of the first embodiment (see FIG. 2). The case 161 has a rectangular parallelepiped
shape, and the bottom of the water contact portion 162 which sinks under the water surface WS
is a metal water contact portion 163 (thickness tc = 6.0 mm) made of an aluminum alloy. The
ultrasonic transducer 6 (specifically, the aluminum matching body 62) is closely adhered to the
inner side surface 163B of the metal water contact portion 163. The cable 66 of the ultrasonic
transducer 6 is taken out of the case 161 in a fluid-tight manner and connected to the main
device 150.
[0085]
Thus, also in the underwater ultrasonic wave search apparatus 140, the drive of the drive power
04-05-2019
35
supply 151 of the main body 150 is driven at the predetermined frequency (in this example, f =
120 kHz) to emit the metal contact portion 613 Ultrasonic wave USR can be emitted from the
surface 163F. In addition, ultrasonic waves USP incident on the radiation surface 3 can be
received by the ultrasonic transducer 6.
[0086]
Moreover, as in the first embodiment, the ultrasonic transducer 6 is provided with the aluminum
matching body 62 having the multi-pillar portion 62D, and the thickness (dimension in the axis
AX direction) of the aluminum matching body 62 is ts. Assuming that the wavelength of the
ultrasonic vibration is λs, the thickness (dimension in the axis AX direction) of the metal water
contact portion 163 of the case 161 is tc, and the wavelength of ultrasonic vibration transmitting
this is λc, the following equation (2) is satisfied: The thickness ts of the aluminum matching
body 62 is adjusted. 1 / 2-1 / 10 ≦ tc / λc + ts / λs ≦ 1/2 + 1/10 formula (2)
[0087]
Specifically, in the underwater ultrasonic probe 140 according to the second embodiment, f =
120 kHz, vs = 4940 m / s, vc = 6445 m / s, so λs = 41.17 mm and λc = 53.79 mm. . また、
ts=15.0mm,tc=6.0mmである。 For this reason, tc / λc + ts / λs = 0.48, which
is understood to be included in the range of the equation (2). The sound velocity vc in the
thickness direction of the metal water contact portion 163 is also measured by measuring the
thickness of the metal water contact portion 163 using an ultrasonic thickness gauge whose
frequency is known, and compared with the separately measured thickness tc The actual sound
velocity vc was calculated from.
[0088]
The equation (2) will be described. In equation (2) as well as equation (1) above, the value of tc /
λc + ts / λs is set to ± 1/10 with the allowable width centered on tc / λc + ts / λs = 1/2. is
there. In this equation (2), the ultrasonic vibration wave that propagates through the aluminum
matching body 62 and the metal water contact portion 163 is effectively contained in 1⁄2 of the
wave (1⁄2 wavelength). It shows that it is preferable to set it as a relationship or a dimensional
relationship approximate to this.
04-05-2019
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[0089]
When radiating ultrasonic waves USR from the radiation surface 163F of the metal water contact
portion 163 into the water WT, the aluminum matching body 62 is added to the inner side
surface 163B of the metal water contact portion 163, and the aluminum matching body 62 and
the metal ship The bottom 3 is combined to form an effective λ / 2 resonator. As a result, it is
considered that the ultrasonic wave USR can be efficiently radiated from the radiation surface
163F to the front surface (in water). Also, along with this, it is possible to suppress the
occurrence of side lobes. By combining the aluminum matching body 62 and the metal water
contact portion 163 to constitute an effective λ / 2 resonator, vibration in the thickness
direction (the direction of the axis AX) is selectively excited. It is considered that generation of
vibration (radial vibration) is suppressed. If the allowable width of tc / λc + ts / λs is set to ±
1/10, within this range, the combination of the aluminum matching body 62 and the metal
contact portion 163 is effectively λ / 2. While the ultrasonic wave USR can be efficiently
radiated to water from the radiation surface 3F to the front surface (the direction of the axis AX)
from the radiation surface 3F, the generation of side lobes can be sufficiently suppressed.
[0090]
Moreover, also in the second embodiment, the aluminum matching body 62 is not a simple disk
shape, and in addition to the metal flat plate portion 62P, a multi-pillar portion 62D in which a
large number of substantially square prism-shaped metal columnar portions 62C are arranged in
a grid. In the form of In the multi-pillar portion 62D, ultrasonic vibration in the direction along
the axis AX generated by the piezoelectric element 61 can be transmitted to the metal ship
bottom portion 3 via the large number of metal columnar portions 62C. Moreover, as in the first
embodiment described above, the use of the aluminum alignment body 62 causes vibrations in
directions other than the thickness direction (the direction of the axis AX) as compared to the
case where a disk-shaped aluminum alignment body is used. While generation of (radial direction
vibration) is suppressed and ultrasonic wave USR can be efficiently emitted from the radiation
surface 3F of the metal ship bottom 3 to which the aluminum alignment body 62 is bonded, into
water in the front (axis AX direction) Also, the occurrence of side lobes can be sufficiently
suppressed.
[0091]
04-05-2019
37
Thus, also with the underwater ultrasonic probe 140 of the second embodiment, the ultrasonic
wave USR can be efficiently radiated from the metal water contact portion 163 into water.
Further, the ultrasonic wave USP incident from water can be efficiently transmitted to the
piezoelectric element 61. In addition, the directivity characteristic is improved, and the
occurrence of side lobes can be suppressed. Thus, the underwater ultrasonic probe 140 has good
ultrasonic radiation characteristics and receiving characteristics.
[0092]
Although the present invention has been described above in connection with the first and second
embodiments, the present invention is not limited to the first and second embodiments, and
various changes may be made without departing from the scope of the present invention.
Needless to say. For example, although the example applied to the boat 1 in which the entire hull
is made of aluminum is shown in the first embodiment, the entire hull may be made of, for
example, FRP, wood, etc. The present invention may be applied to a ship such as a boat provided
with a metal ship bottom portion to which 6 can be attached. In the first embodiment, an
example is shown in which the aluminum matching body 62 similarly made of an aluminum alloy
is joined to the metal ship bottom 3 or the metal water contact portion 163 made of an
aluminum alloy, but the metal ship bottom 3 The aluminum matching body 62 may be replaced
with a wavelength matching body of another material according to the material of 163). Under
the present circumstances, it is preferable to comprise a wavelength matching body with the
same material as a metal ship bottom part (metal water contact part), or an alloy of the same
type | system | group.
[0093]
In the underwater ultrasonic wave search device 140 of the second embodiment, the ultrasonic
vibrator 6 is provided in the probe 160. However, in addition to the ultrasonic vibrator 6, the
water temperature gauge, the manipulator, and other devices are included. It is good also as a
thing. Moreover, in Example 2, although illustrated as what uses the probe 160 in the water
surface vicinity, it can also be applied to a form in which the whole probe 160 is submerged in
water. Further, the case 161 is not limited to the rectangular parallelepiped shape, and can be
formed into an appropriate shape as long as the metal water contact portion 163 for fixing the
ultrasonic transducer 6 can be secured. The present invention can also be applied to a manned
search apparatus in which a human gets into the probe.
04-05-2019
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[0094]
Further, in the above-described embodiment, as the aluminum matching body 62, the slits 62L
are formed in a lattice shape to form a multi-pillar portion 62D having a large number of squarepillared metal columnar portions 62C (see FIG. 3). ). However, as the metal columnar portion,
other forms such as triangular columnar shape, hexagonal columnar shape, concentric circle
shape, and one obtained by dividing the same in the circumferential direction can also be
adopted. In addition to the multi-columnar portion 62D, although the metal flat plate portion 62P
is used as the aluminum alignment body 62, a large number of metal columns may be arranged
in a row as the aluminum alignment body. Alternatively, the flat metal portion may be disposed
on both sides in the thickness direction of the metal columnar portion.
[0095]
Furthermore, although the example which filled the slit 62L with the urethane resin was shown
in the above-mentioned Example, it is also possible to set it as the form which is not filled with
resin in the gaps of metal columnar parts, such as slit 62L. Conversely, as the resin to be filled, in
addition to the urethane resin, it is also possible to use a flexible epoxy resin or silicon resin.
[0096]
BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the structure of
the aluminum ship with a fish finder which concerns on Example 1. FIG. It is sectional drawing
concerning Example 1, 2 and which shows the structure of an ultrasonic transducer | vibrator,
and a relationship with a metal ship bottom part or a metal water contact part. (A) is a crosssectional view and (b) is a plan view of the aluminum alignment body of the first and second
embodiments. It is a graph which shows the radiation | emission directivity characteristic of the
ultrasonic wave in the implementation sample 1 which adhere | attached the ultrasonic
transducer | vibrator concerning a present Example to the aluminum plate which imitated an
aluminum ship. It is a graph which shows the radiation | emission directivity characteristic of the
ultrasonic wave in the ultrasonic transducer | vibrator concerning the comparative example 1.
FIG. It is a graph which shows the radiation | emission directivity characteristic of the ultrasonic
wave in the comparative sample 2 which adhere | attached the ultrasonic transducer | vibrator
concerning the comparative example 2 to the aluminum plate which imitated the aluminum ship.
It is a graph which shows the radiation | emission directivity characteristic of an ultrasonic wave
in the ultrasonic transducer | vibrator concerning a reference sample. It is a graph which shows
04-05-2019
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the frequency characteristic of transmitting sound pressure about the implementation sample 1,
the comparative example 1, and the comparison sample 2. FIG. It is a graph which shows the
frequency characteristic of receiving sensitivity about the implementation sample 1, the
comparative example 1, and the comparative sample 2. FIG. It is a display image of the fish finder
in a boat, and (a) relates to Example 1 and (b) to Comparative Example 2. FIG. 7 is an explanatory
view showing a configuration of an underwater ultrasonic wave search apparatus according to a
second embodiment.
Explanation of sign
[0097]
10 A boat with a fish finder (a boat with an underwater ultrasonic wave utilization device) 1 a
boat 2 a boat bottom 3 of a metal boat bottom portion tb a thickness of a metal boat bottom
portion vb a speed of sound of ultrasonic vibration traveling along a metal boat bottom portion
Wavelength of ultrasonic vibration of a given frequency to be transmitted Wave 3B (at the
bottom of a metal ship) Inside surface 3F (at the bottom of a metal ship) Radiation surface 4 (at
the bottom of a metal ship) Power supply 52 Display 6 Ultrasonic transducer 61 Piezoelectric
element (vibrating element) 61F Front surface 61B Back surface AX (Piezoelectric element) Axis f
Vibration frequency of the vibrating element (driving frequency of drive power) 62 Aluminum
matching body (wavelength matching body) 62F Front side 62B Back side 62C Metal columnar
part 62D Multi-column part 62P Flat metal part 62M (of aluminum matching body) Metal part
62L Slit 62J Filled resin ts thickness of aluminum matching body td thickness direction
dimension of metal columnar part vs speed of sound of ultrasonic vibration transmitting
aluminum matching body λs wavelength of ultrasonic vibration transmitting predetermined
wavelength matching body Wc side dimension of metal columnar part Wj metal Size of gap
between pillars (width of filled resin part) 63 buffer body 140 underwater ultrasonic probe 161
case of water ultrasonic probe 162 water contact part 163 metal contact part tc thickness of
metal contact part (Thickness of the portion of metal water contact portion where ultrasonic
vibration is transmitted) vc Sound speed of ultrasonic vibration transmitted through metal water
contact portion λ c Wavelength 163 B of ultrasonic vibration of predetermined frequency
transmitted through metal water contact portion (metal water contact portion ) Inside surface
163F (for metal contact)
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