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JP2001050940

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DESCRIPTION JP2001050940
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
ultrasonic transducer that mutually converts an electric signal and an ultrasonic wave. In
particular, the present invention relates to an ultrasonic transducer that can be suitably used for
nondestructive inspection performed by irradiating ultrasonic waves to an object in air.
[0002]
2. Description of the Related Art FRP (fiber reinforced plastics) is used as a material for a fuel
tank of an aircraft or a rocket for an artificial satellite because of its light weight and high
strength.
[0003]
The internal inspection of an FRP molded product such as a fuel tank composed of FRP is
performed by acquiring a tomographic image of the FRP molded product which is an inspection
object by an X-ray imaging apparatus, and obtaining a fault of the acquired inspection object It is
generally performed by a so-called X-ray nondestructive inspection method of judging the
presence or absence of a defect from an image.
However, in this X-ray nondestructive inspection method, when irradiating an X-ray to a to-beinspected object, there exists a possibility that the inspection worker itself may receive X-ray and
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to be exposed. In addition, in order to acquire a single tomographic image, X-rays must be
irradiated onto the subject from a large number of angles (directions), which causes a large
amount of time and labor.
[0004]
Therefore, recently, as ultrasonic technology has progressed, nondestructive inspection methods
using ultrasonic waves have been proposed.
[0005]
For example, by immersing the test object in water, transmitting ultrasonic waves toward the test
object in the water, and observing a transmitted wave or a reflected wave from the test object,
Methods have been proposed to inspect the presence or absence of internal defects.
However, in this inspection method, when the object to be inspected is a large-sized one like the
above-described fuel tank, a large water tank for immersing the object to be inspected is also
required. Moreover, in the case where the inspection object is a FRP molded product, the
inspection can not be performed because the water immersion to the FRP becomes a problem.
[0006]
As another method, while rolling the rubber roller on the surface of the object to be inspected,
ultrasonic waves are transmitted toward the inside of the object to be inspected through the
rubber roller, and the inside of the object to be inspected is Although a method has been
proposed for inspecting the presence or absence of internal defects in an inspection object by
observing a reflected wave, this method has a complex surface shape that can not be rolled while
contacting a rubber roller. You can not inspect what you have.
[0007]
As still another method, ultrasonic waves are transmitted toward the test object placed in the air,
and the transmitted waves from the test object are observed to check the presence or absence of
the internal defect of the test object, etc. A method of inspection has been proposed.
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According to this method, unlike the method in which the object to be inspected is immersed in
water for inspection, the water tank is not necessary, and the inspection can be performed even if
the object to be inspected is an FRP molded product. In addition, the surface shape of the object
to be inspected is not complicated.
[0008]
An example of the construction of an ultrasonic transducer for transmitting ultrasonic waves into
the air is disclosed as a prior art in, for example, Japanese Patent Publication No. 61-3159. That
is, as shown in FIG. 6, the ultrasonic transducer has a case 91 whose one end face is open, a
diaphragm 92 provided to close the open end face of the case 91, and a case of the diaphragm
92 And an ultrasonic transducer 93 fixed to a surface facing in the inside of 91. Lead wires 94 a
and 94 b for applying a voltage to the ultrasonic transducer 93 are connected to the ultrasonic
transducer 93.
[0009]
With this configuration, when a voltage is applied to the ultrasonic transducer 93 through the
lead wires 94a and 94b, the ultrasonic transducer 93 is excited and the ultrasonic transducer 93
and the diaphragm 92 are integrated. In this case, the bending vibration causes an ultrasonic
wave to be generated. Also, when ultrasonic vibration is applied to the diaphragm 92, the applied
ultrasonic vibration propagates from the diaphragm 92 to the ultrasonic transducer 93 and is
converted to an electric signal (voltage) by the ultrasonic transducer 93. It is converted and
output through the lead wires 94a and 94b.
[0010]
Problems to be Solved by the Invention In a nondestructive inspection performed by irradiating
an inspection object with ultrasonic waves in the air, in order to find an internal defect of several
millimeters (for example, 3 mm or less), the wavelength is It is necessary to transmit an
ultrasonic wave of about several millimeters to the object to be inspected. Therefore, this
inspection requires an ultrasonic transducer capable of transmitting ultrasonic waves with a
frequency of several hundreds kHz (for example, 300 kHz or more). However, since the
frequency of the ultrasonic wave generated by the flexural vibration of the diaphragm 92 and the
ultrasonic transducer 93 is about 13 to 32 kHz, the above ultrasonic transducer irradiates the
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ultrasonic wave to the inspection object in the air. Can not be applied to nondestructive
inspection.
[0011]
Moreover, in the above-described configuration, even if ultrasonic waves of 300 kHz or more can
be generated, the ultrasonic waves generated by the vibration of the diaphragm 92 and the
ultrasonic transducer 93 are air from the diaphragm 92. Even though the sound pressure is small
because it is diffused and emitted, ultrasonic waves with a frequency of 300 kHz or more may be
attenuated and disappear before reaching the test object because the attenuation in air is very
large. is there.
[0012]
Therefore, an object of the present invention is to solve the above-mentioned technical problems
and to provide an ultrasonic transducer capable of transmitting an ultrasonic wave having a high
frequency and a large sound pressure.
[0013]
[Means for Solving the Problems and Effects of the Invention] The inventor of the present
invention has conducted intensive studies to meet the above problems, and a conventional
ultrasonic transducer is an integrated unit of an ultrasonic transducer and a diaphragm. It was
noticed that only a low frequency ultrasonic wave of about 13 to 32 kHz could be generated
because of the configuration to generate the ultrasonic wave by the flexural vibration.
Then, it has been found that generation of ultrasonic waves of several hundreds kHz is possible
by omitting the diaphragm.
In addition, by forming a waveguide on the ultrasonic wave transmitting / receiving surface side
of the ultrasonic transducer to enhance the directivity of the ultrasonic wave, it is possible to
increase the sound pressure of the ultrasonic wave transmitted from the ultrasonic transducer. I
found that.
[0014]
That is, according to the first aspect of the present invention, when an electric signal is input, the
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ultrasonic wave is excited to transmit ultrasonic waves from the ultrasonic wave transmitting /
receiving surface, and when ultrasonic waves are incident to the ultrasonic wave transmitting /
receiving surface, the ultrasonic waves are transmitted. It is characterized in that it includes an
ultrasonic transducer for converting into an electric signal, and a substantially cylindrical
waveguide portion formed to extend in the ultrasonic wave transmission direction on the
ultrasonic wave transmitting / receiving surface side of the ultrasonic transducer. It is an
ultrasonic transducer.
[0015]
According to the present invention, unlike the configuration in which ultrasonic waves are
generated by bending and vibrating the ultrasonic transducers and the diaphragm integrally, it is
possible to transmit ultrasonic waves with a high frequency of several hundreds kHz. it can.
[0016]
Further, by forming the waveguide on the ultrasonic transmitting / receiving surface side of the
ultrasonic transducer, the directivity of the ultrasonic wave generated by the excitation of the
ultrasonic transducer is enhanced to converge the vibration energy of the ultrasonic wave. As a
result, the sound pressure of the ultrasonic waves transmitted from the ultrasonic transducer 1
can be increased.
Therefore, the ultrasonic waves transmitted from the ultrasonic transducer propagate well in air
even at a high frequency of several hundreds kHz.
[0017]
According to a second aspect of the present invention, the ultrasonic transducer is a 1-3
composite piezoelectric body in which a plurality of columnar piezoelectric bodies are arranged
substantially in parallel and substantially at regular intervals in a synthetic resin matrix. It is an
ultrasonic transducer according to claim 1 characterized by the above.
[0018]
According to the present invention, each columnar piezoelectric material of the 1-3 composite
piezoelectric material is polarized in the thickness direction, and in response to the input of the
electric signal, only in the thickness direction (height direction of the columnar piezoelectric
material) Since it is excited, there is no possibility that the oscillation frequency is lowered due to
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the ultrasonic transducer being excited in the direction orthogonal to the thickness direction, and
a high frequency of several hundreds kHz (for example, 300 kHz or more) The waves can be
transmitted well.
[0019]
Further, since the 1-3 composite piezoelectric material has a large piezoelectric constant, weak
ultrasonic waves can be detected well and converted into electrical signals.
[0020]
A plurality of waveguides may be formed on the ultrasonic transmission / reception surface side,
and the plurality of waveguides may be formed in correspondence with a predetermined number
of columnar piezoelectric members. Good (claim 3).
[0021]
The waveguide may be formed such that the opening area of the end on the ultrasonic
transmission / reception surface side is substantially the same as the area of the ultrasonic
transmission / reception surface (Claim 4).
[0022]
The invention according to claim 5 is characterized in that the waveguide is formed so that the
opening area becomes larger toward the downstream side of the ultrasonic wave transmission
direction. It is an ultrasonic transducer described in.
[0023]
According to the present invention, since the waveguide is formed such that the opening area
becomes larger toward the downstream side of the ultrasonic wave transmission direction, the
sound pressure of the ultrasonic wave transmitted through the waveguide can be obtained. While
preventing the standing wave (standing wave) from being generated in the waveguide.
[0024]
Preferably, the waveguide has a length of at least one wavelength of the ultrasonic wave
transmitted from the ultrasonic wave transmitting / receiving surface.
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In this case, the directivity of the ultrasonic wave transmitted through the waveguide can be
reliably improved.
[0025]
Also, the waveguide section divides the square value of the radius R (mm) of the ultrasonic wave
transmitting / receiving surface of the ultrasonic transducer by the wavelength λ (mm) of the
ultrasonic wave transmitted from the ultrasonic wave transmitting / receiving surface. It is
preferable that the length of the near-field sound field obtained by
In this case, the generation of standing waves in the waveguide member can be better prevented.
[0026]
According to a sixth aspect of the present invention, the surface opposite to the ultrasonic wave
transmitting / receiving surface of the ultrasonic transducer is an undesired ultrasonic wave
transmitting surface for transmitting undesired ultrasonic waves, wherein the ultrasonic
transducer is 6. The apparatus according to any one of claims 1 to 5, further comprising a
substantially cylindrical wave-breaking portion formed extending in the direction of the
undesired ultrasonic wave on the side of the undesired ultrasonic wave transmitting surface. It is
an ultrasonic transducer.
[0027]
According to the present invention, a substantially cylindrical wave-breaking portion is formed
extending in the undesired ultrasonic wave transmission direction on the side of the undesired
ultrasonic wave transmission surface of the ultrasonic transducer.
Therefore, if the wave-breaking member is made of a sound-absorbing material such as soft
rubber, for example, it is possible to break the unwanted ultrasonic waves sent out from the
unwanted ultrasonic wave delivery surface.
[0028]
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The invention as set forth in claim 7 is the ultrasonic transducer according to claim 6,
characterized in that the inner surface of the wave-breaking part is subjected to concavo-convex
processing.
[0029]
According to the present invention, it is possible to scatter and break the undesired ultrasonic
wave transmitted from the undesired ultrasonic wave transmitting surface when it is reflected by
the inner surface of the wave reduction portion.
[0030]
According to an eighth aspect of the present invention, in the case where the ultrasonic
transducer emits ultrasonic waves emitted from the ultrasonic transducer toward the air and
emits them, even ultrasonic transducers may be used. Even if the frequency of the ultrasonic
wave transmitted from the antenna is high, the ultrasonic wave emitted from the waveguide
propagates well in air because the sound pressure is increased while passing through the
waveguide.
Therefore, this ultrasonic transducer can be suitably used for nondestructive inspection carried
out by irradiating ultrasonic waves to the object in air.
[0031]
When the ultrasonic transducer is composed of a 1-3 composite piezoelectric material, the
composition of the 1-3 composite piezoelectric material is adjusted to obtain the acoustic
impedance of the 1-3 composite piezoelectric material (ultrasonic transducer) as air. By
approximating to the acoustic impedance of the above, the transmittance from the ultrasonic
transducer to the air can be improved, and ultrasonic waves generated by the excitation of the
ultrasonic transducer can be favorably transmitted to the air.
[0032]
DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be
described in detail with reference to the accompanying drawings.
[0033]
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FIG. 1 is an illustrative view for explaining a nondestructive inspection performed using an
ultrasonic transducer according to an embodiment of the present invention.
The nondestructive inspection using the ultrasonic transducers 1 and 1 can be performed by
arranging the inspection object S in the air.
Therefore, the inspection object S can be inspected even if it is a large one such as, for example, a
fuel tank of an aircraft or a rocket for an artificial satellite, or the surface shape is complicated.
In addition, even if the inspection object S is a FRP molded product, unlike the ultrasonic
nondestructive inspection performed by immersing the inspection object S in water, the
inspection can be performed without causing the problem of water immersion in FRP, etc. it can.
[0034]
One of the ultrasonic transducers 1 is a transmitting ultrasonic transducer for transmitting
ultrasonic waves toward the object S when an electric signal is input from an inspection device
main body (not shown).
The other ultrasonic transducer 1 receives the ultrasonic wave transmitted through the object S,
converts the ultrasonic wave into an electric signal (voltage) according to the sound pressure,
and supplies the ultrasonic wave to the inspection apparatus main body. It is a transducer.
[0035]
In the nondestructive inspection of the object S, the ultrasonic transducer 1 for transmitting and
the ultrasonic transducer 1 for receiving are opposed to each other across the object S, and each
of the objects to be inspected. It is moved (scanned) in the direction intersecting with the
ultrasonic wave delivery direction while maintaining the positional relationship at a
predetermined distance (for example, 200 mm) from the body S.
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During this scan, transmission of ultrasonic waves from the ultrasonic transducer 1 for
transmission toward the subject S continues.
The ultrasonic waves transmitted from the ultrasonic transducer 1 for transmission are
transmitted through the subject S, enter the ultrasonic transducer 1 for reception, and are
converted into electrical signals.
The attenuation amount of the ultrasonic wave transmitted through the portion where the
internal defect of the inspection object S exists and the attenuation amount of the ultrasonic
wave transmitted through the portion where the internal defect does not exist are different from
each other. Based on the electric signal output from 1, it can be determined whether the internal
defect of the to-be-tested object S exists.
[0036]
FIG. 2 is an end view of the ultrasonic transducer 1 cut along a plane parallel to the direction of
ultrasonic wave transmission.
The ultrasonic transducer 1 excites and transmits an ultrasonic wave when an electric signal is
input and a substantially cylindrical case 11 whose one surface is closed, and when the ultrasonic
vibration is applied, the ultrasonic vibration is electricized. An ultrasonic transducer 12 for
converting into a signal, and a holding member 13 for holding the ultrasonic transducer 12 near
the open end face of the case 11 are provided.
[0037]
At the closed end face of the case 11, a connector 15 connected to the inspection apparatus main
body (not shown) via a cable 14 is provided in a penetrating manner.
Two lead wires 16 a and 16 b are drawn out from the connector 15, and the tips of the lead
wires 16 a and 16 b are connected to the ultrasonic transducer 12. Thereby, an electric signal
(voltage) can be input from the inspection apparatus main body to the ultrasonic transducer 12
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through the cable 14, the connector 15, and the lead wires 16a and 16b. Further, the electrical
signal generated by the ultrasonic transducer 12 can be applied to the inspection apparatus main
body via the lead wires 16 a and 16 b, the connector 15 and the cable 14.
[0038]
The ultrasonic transducer 12 is formed of a flat cylindrical 1-3 composite piezoelectric body, and
the end face 12a facing the outside of the case 11 sends out an ultrasonic wave generated by the
excitation of the ultrasonic transducer 12. And an ultrasonic transmission / reception surface for
receiving ultrasonic waves incident from the outside. A plurality of (1-3 in this embodiment) PZT
(lead zirconate titanate) in a matrix 121 made of synthetic resin such as epoxy resin, silicon resin
or urethane resin is used as the 1-3 composite piezoelectric material. And 1-3 cylindrical
piezoelectric bodies 122 are arranged parallel to each other at equal intervals. A cross-sectional
view of the ultrasonic transducer 12 taken along a plane parallel to the end face is shown in FIG.
[0039]
Each cylindrical piezoelectric body 122 is polarized in the height direction (the thickness
direction of the ultrasonic transducer 12). Therefore, the ultrasonic transducer 12 is excited only
in the thickness direction by the voltage applied through the lead wires 16a and 16b. Therefore,
there is no possibility that the oscillation frequency is lowered due to excitation of the ultrasonic
transducer 12 in the radial direction (direction orthogonal to the thickness direction), and a high
frequency of several hundreds kHz (for example, 300 kHz or more) from the ultrasonic
transmitting / receiving surface 12a. Longitudinal waves of frequency can be transmitted well.
Moreover, since the cylindrical piezoelectric body 122 has no anisotropy in the radial direction,
the ultrasonic transducer 12 using this cylindrical piezoelectric body 122 is a 1-3 composite
piezoelectric using the piezoelectric body formed in a prismatic shape. Compared to the body, the
decrease in oscillation frequency due to radial excitation is even less. In addition, since the 1-3
composite piezoelectric body has a large piezoelectric constant, the ultrasonic transducer 12
made of the 1-3 composite piezoelectric body can detect weak ultrasonic waves well and convert
it into an electric signal. Therefore, the detection sensitivity of the ultrasonic transducer 1 can be
improved.
[0040]
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11
A matching layer 17 for matching the acoustic impedance between the ultrasonic transducer 12
and air is provided on the ultrasonic transmitting / receiving surface 12a of the ultrasonic
transducer 12. The matching layer 17 preferably has an acoustic impedance that is about an
intermediate value between the acoustic impedance of the ultrasonic transducer 12 and the
acoustic impedance of air, and, for example, the same synthetic resin as the matrix 121 of the
ultrasonic transducer 12 It can be composed of materials.
[0041]
The holding member 13 is a synthetic resin molded product formed in a substantially cylindrical
shape. For example, an epoxy resin, a silicon resin, a urethane resin, or a rubber can be used as a
material of the holding member 13. From the viewpoint of adhesion and bonding, the structure
of the matrix 121 of the ultrasonic transducer 12 can be used. It is preferable to use the same
synthetic resin as the material.
[0042]
The holding member 13 is fixed to the case 11 by, for example, an epoxy adhesive in a state
where approximately half of the outer peripheral surface is joined to the inner peripheral surface
of the case 11. A stepped portion 131 is formed over the entire circumference substantially at
the center of the inner peripheral surface of the holding member 13, and the ultrasonic vibrator
12 is locked and fixed to the stepped portion 131 to thereby fix the ultrasonic transducer. A
position 12 is held at a position where it slightly enters the case 11 from the open end face of the
case 11.
[0043]
A portion downstream of the step portion 131 of the holding member 13 in the ultrasonic wave
transmitting direction is a waveguide for preventing the diffusion of the ultrasonic wave
transmitted from the ultrasonic wave transmitting / receiving surface 12a of the ultrasonic
transducer 12. The portion 132 is formed. That is, the ultrasonic waves transmitted from the
ultrasonic wave transmitting / receiving surface 12 a of the ultrasonic transducer 12 are given
directivity and emitted when passing through the inside of the waveguide portion 132. Thereby,
the vibrational energy of the ultrasonic wave sent from the ultrasonic wave transmission /
reception surface 12a converges, and as a result, the sound pressure of the ultrasonic wave is
03-05-2019
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increased.
[0044]
On the other hand, the portion of the holding member 13 upstream of the stepped portion 131
in the ultrasonic wave delivery direction is a surface (non-desired ultrasonic wave delivery
surface) 12b opposite to the ultrasonic wave transmission / reception surface 12a of the
ultrasonic transducer 12. A wave-breaking unit 133 is provided to break the transmitted
ultrasonic waves. The inner surface 133a of the wave absorption part 133 is an uneven surface
by being subjected to an uneven processing such as a knurling process for forming a plurality of
grooves in a cross shape, for example. Thereby, the undesired ultrasonic waves transmitted from
the undesired ultrasonic wave transmitting surface 12b are scattered when being reflected by the
inner surface 133a of the wave-breaking portion 133, and are attenuated while being repeatedly
scattered by this reflection. .
[0045]
As described above, according to this embodiment, since the ultrasonic wave is generated and
transmitted by the excitation of the ultrasonic wave vibrator 12, the ultrasonic wave vibrator and
the diaphragm are integrally bent and vibrated. Unlike the configuration that generates
ultrasonic waves, high frequency ultrasonic waves of several hundreds kHz can be transmitted.
[0046]
Further, since the ultrasonic transducer 12 is formed of a 1-3 composite piezoelectric material
and the excitation in the radial direction of the ultrasonic transducer 12 is small, there is a
possibility that the oscillation frequency may be lowered by the excitation in the radial direction.
There is no
Therefore, it is possible to transmit an ultrasonic wave of higher frequency than in the case of
using a piezoelectric body (PZT piezoelectric body) consisting only of PZT.
[0047]
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13
Furthermore, while the acoustic impedance of the PZT piezoelectric material is about 3 × 10 7
(kg / m 2 · s), the acoustic impedance of the 1-3 composite piezoelectric material is about 7.84 ×
10 6 (kg / m 2). S). Therefore, since the acoustic impedance of air is 4.12 × 10 2 (kg / m 2 · s),
the ultrasonic transducer 12 made of the 1-3 composite piezoelectric material is generated due
to excitation as compared to the PZT piezoelectric material. The ultrasonic waves can be incident
on air better.
[0048]
In order to support this effect, the transmittance of acoustic energy from the 1-3 composite
piezoelectric body to the air and the transmittance of acoustic energy from the PZT piezoelectric
body to the air are determined as the 1-3 composite piezoelectric material. The transmission of
acoustic energy from the body to the air is about -74 dB, the transmission of acoustic energy
from the PZT piezoelectric to the air is about -85 dB, and the ultrasonic waves generated from
the 1-3 composite piezoelectrics are from the PZT piezoelectrics. It turns out that it injects into
air better than the generated ultrasonic wave.
[0049]
When the ultrasonic transducer 1 is used as an ultrasonic transducer for receiving waves, the
ultrasonic transducer 12 is formed of a 1-3 composite piezoelectric material having a large
piezoelectric constant, so that it is very weak. There is also an effect that sound waves can be
detected well and converted into electric signals.
[0050]
Further, by forming the waveguide portion 132 on the ultrasonic wave transmitting / receiving
surface 12 a side of the ultrasonic transducer 12, the directivity of the ultrasonic wave generated
by the excitation of the ultrasonic transducer 12 is enhanced, and the ultrasonic wave is
generated. The vibrational energy can be converged, and as a result, the sound pressure of the
ultrasonic waves transmitted from the ultrasonic transducer 1 can be increased.
Therefore, the ultrasonic waves transmitted from the ultrasonic transducer 1 propagate well in
the air even at a high frequency of several hundreds kHz.
Therefore, the ultrasonic transducer 1 can be suitably used for nondestructive inspection
performed by irradiating the object S (see FIG. 1) with ultrasonic waves in air.
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[0051]
The waveguide section 132 preferably has a length of one or more wavelengths of the ultrasonic
wave transmitted from the ultrasonic wave transmitting / receiving surface 12a of the ultrasonic
transducer 12. The directivity of the ultrasonic wave transmitted via the wave unit 132 can be
reliably enhanced. Also, the waveguide unit 132 divides the square value of the radius R (mm) of
the ultrasonic wave transmission / reception surface 12 a of the ultrasonic transducer 12 by the
wavelength λ (mm) of the ultrasonic wave transmitted from the ultrasonic transmission /
reception surface 12 a. It is preferable that the length of the near-field sound field obtained by
For example, if the frequency of the ultrasonic wave transmitted through the waveguide 132 is
300 kHz and the radius of the ultrasonic wave transmitting / receiving surface 12a is 15 mm, the
wavelength of the ultrasonic wave is 1.1 mm, and the near-field sound field is generated. The
length of the waveguide 132 is calculated to be about 204 mm, so the waveguide 132 is
preferably formed shorter than about 20 cm. This can prevent the generation of standing waves
in the waveguide portion 132.
[0052]
FIG. 4 is an end view for explaining another configuration of the ultrasonic transducer. In FIG. 4,
parts corresponding to the parts shown in FIG. 2 described above are denoted by the same
reference numerals as in FIG. 2.
[0053]
The waveguide portion 132 of the ultrasonic transducer shown in FIG. 4 is formed such that the
opening area becomes larger toward the downstream side of the ultrasonic wave transmitting
direction. In other words, the inner diameter of the waveguide portion 132 increases toward the
downstream side in the ultrasonic wave delivery direction. As a result, the sound pressure of the
ultrasonic wave transmitted through the waveguide 132 can be increased, and the generation of
a standing wave in the waveguide 132 can be favorably prevented.
[0054]
The cross-sectional shape of the inner peripheral surface of the waveguide portion 132 may be
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linear as shown in FIG. 4 or may be a curved shape (exponential horn shape) curved
exponentially. Good.
[0055]
FIG. 5 is an end view for explaining still another configuration of the ultrasonic transducer.
In FIG. 5, parts corresponding to the respective parts shown in FIG. 2 described above are
denoted by the same reference numerals as in FIG.
[0056]
In the ultrasonic transducer shown in FIG. 5, a plurality of waveguides 134 are formed on the
downstream side of the stepped portion 131 of the holding member 13 in the ultrasonic wave
delivery direction. Each of the waveguides 134 is provided in correspondence with a
predetermined number (for example, one) of cylindrical piezoelectric bodies 122, and ultrasonic
waves generated by excitation of the corresponding cylindrical piezoelectric bodies 122 are
diffused. Prevent radiation. Also according to this configuration, the directivity of the ultrasonic
wave generated by the excitation of the ultrasonic transducer 12 can be enhanced, and the
vibrational energy of the ultrasonic wave can be converged. As a result, the ultrasonic wave
transmitted from the ultrasonic transducer Sound pressure can be increased.
[0057]
The ultrasonic transducer shown in FIG. 5 can be suitably used particularly as a transducer for
transmitting waves.
[0058]
Although the embodiments of the present invention have been described above, the present
invention is not limited to the above-described embodiments.
For example, in the configuration shown in FIG. 2 or FIG. 4, by integrally molding the holding
03-05-2019
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member 13 with a synthetic resin, the wave guide portion 132 and the wave absorption portion
133 are integrally formed. You may form separately from the wave absorption part 133. FIG.
[0059]
Further, when the waveguide portion 132 (134) and the wave absorption portion 133 are
separately formed, the wave absorption portion 133 is formed, for example, by a material having
a sound absorbing property such as soft rubber. Uneven machining on the inner surface 133a of
the wave portion 133 can be omitted. That is, if the wave absorption portion 133 is formed of a
material having sound absorbing properties, it is desirable that the ultrasonic wave transmission
/ reception surface 12 a of the ultrasonic transducer 12 is transmitted even if the inner surface
133 a of the wave absorption portion 133 is not uneven Not able to squeeze ultrasonic waves.
[0060]
Various other design changes can be made within the scope of the technical matters described in
the claims.
[0061]
Brief description of the drawings
[0062]
1 is an illustrative view for explaining a nondestructive inspection performed using an ultrasonic
transducer according to an embodiment of the present invention.
[0063]
FIG. 2 is an end view of the ultrasonic transducer cut along a plane parallel to the ultrasonic
wave delivery direction.
[0064]
3 is a cross-sectional view when the ultrasonic transducer is cut along a plane parallel to the end
face.
[0065]
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4 is an end view for explaining another configuration of the ultrasonic transducer.
[0066]
5 is an end view for explaining still another configuration of the ultrasonic transducer.
[0067]
6 is a cross-sectional view showing the configuration of a conventional ultrasonic transducer.
[0068]
Explanation of sign
[0069]
Reference Signs List 1 ultrasonic transducer 12 ultrasonic transducer 12a ultrasonic transmitting
/ receiving surface 12b undesired ultrasonic wave transmitting surface 121 matrix 122
cylindrical piezoelectric body 132, 134 waveguide 13 holding member 133 wavebreaker 133a
inner surface of wavebreaker
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