JP5105851B2 - Ultrasonic probe - Google Patents

Description

  The present invention relates to an ultrasonic probe for inspecting a deterioration state of a pipe or a thin cylindrical tube, and more particularly, a non-destructive inspection suitable for inspecting a long distance section collectively using a guide wave. It relates to an acoustic probe.

  A conventional ultrasonic probe for transmitting / receiving ultrasonic waves includes a piezoelectric vibrator made of PZT or the like that performs electrical / acoustic conversion, a holding body disposed on one side of the piezoelectric vibrator, The piezoelectric vibrator includes a protective plate disposed on the opposite side of the holding plate.

  A typical example of inspecting the deterioration state of the pipe using such an ultrasonic probe is an ultrasonic thickness gauge. The ultrasonic thickness gauge uses an ultrasonic sensor (probe) consisting of a piezoelectric vibrator to excite elastic waves in the pipe and receive the elastic waves reflected from the bottom wall of the pipe to receive the thickness of the pipe. Measure. Since the measurement range of this apparatus is equal to the size of the sensor, when a long pipe is to be measured, the number of measurement points increases and a lot of time is required.

  As one countermeasure against such a problem, using a guide wave that is an elastic wave formed by interference of a longitudinal wave and a transverse wave that propagates while reflecting and mode-converting in an object having a boundary surface like a pipe, There is a method for inspecting long distance sections at once.

  As an ultrasonic probe using a guide wave, for example, the one shown in FIG. 4 or FIG. 11 of Japanese Patent No. 3732513 is known. In the one shown in FIG. 4 of Japanese Patent No. 3732513, a loss material of tungsten-added epoxy is filled in the chamber so that the piezoelectric element does not break due to pressure contact with the pipe of the subject, and the piezoelectric element is fixed. . Moreover, in what was shown in FIG. 11 of the patent 3732513 gazette, the piezoelectric element was directly adhere | attached on the support block.

Japanese Patent No. 3732513

  However, in the one shown in FIG. 4 of Japanese Patent No. 3732513, since the entire surface of the piezoelectric element is bonded with a loss material, if a crack or the like occurs due to a defect or deterioration in the loss material, the pressure contact is made. If a load is locally generated on the piezoelectric element, it may be damaged.

  Further, in the one shown in FIG. 11 of Japanese Patent No. 3732513, the piezoelectric element is directly bonded to the support block, so that it can withstand pressure contact, but there is a problem that the reverberation cannot be sufficiently attenuated.

  An object of the present invention is to provide an ultrasonic probe that is strong against pressure contact with a subject and sufficiently attenuates reverberation.

(1) In order to achieve the above object, the present invention provides an ultrasonic probe comprising an ultrasonic transducer, electrodes formed on both surfaces of the ultrasonic transducer, and a protective plate for protecting the electrode. And having a rectangular parallelepiped shaped holding body for changing the resonance frequency of the ultrasonic transducer and a concave portion for housing the holding body, while surface-bonding to one of the protection plates. A case in which the holding body is attached and fixed in the concave portion, and an insulating curable resin filled in a gap between the concave portion of the case and the holding body are provided.
With this configuration, it is strong against pressure contact with the subject, and the reverberation is sufficiently attenuated.

  (2) In the above (1), preferably, the surface of the protective plate in contact with the subject has a convex shape in the direction of the subject.

  (3) In the above (1), preferably, the holding body is formed with a recess that matches the shape of the ultrasonic transducer and the protective plate at a portion where the ultrasonic transducer and the protective plate are attached. It is what.

  According to the present invention, it is strong against pressure contact with a subject, and attenuation of reverberation is sufficient.

First, the configuration of the ultrasonic probe according to the first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a cross-sectional view showing the configuration of the ultrasonic probe according to the first embodiment of the present invention. 1A is a front sectional view, and FIG. 1B is a side sectional view.

  As shown in FIGS. 1 (A) and 1 (B), the ultrasonic vibrator 1 is a shear vibration piezoelectric element made of lead zirconate titanate PZT and manufactured in a plate shape. Electrodes 3 are formed on both surfaces of the ultrasonic vibrator 1. The electrode 3 is formed by, for example, a silver paste baking method or an electroless nickel plating method. A plate-shaped protection plate 2 is bonded to each surface of the electrode 2 of the ultrasonic transducer 1 in order to protect the ultrasonic transducer 1.

  Here, as shown in FIG. 1B, the plate-shaped protection plate 2 is adhered to the entire surface (the lower surface in the drawing) that contacts the subject, and the other surface (the upper surface in the drawing). Is bonded to the surface excluding the part where the lead wire 11 is attached to both side electrodes of the ultrasonic transducer 1. As the protective plate 2, an alumina ceramic material having sufficient strength is used. The protective plate 2 may be an epoxy-based material or a metal material if the electrode surface and the protective plate are insulated if they have sufficient strength.

  The lead wire 11 is connected to both positive and negative electrodes of the ultrasonic vibrator 1 by soldering 4 or an adhesive. The lead wire 11 is preferably a shielded signal line coaxial cable. After the lead wire 11 is connected, the impurities of the solder and adhesive of the electrode part are thoroughly washed with a solvent and wiped cleanly.

The ultrasonic transducer 1 to which the lead wire 11 is connected is bonded to the metal holder 5 on the surface side to which the lead wire 11 is attached. The metal holding body 5 has a rectangular parallelepiped shape made of iron-base alloy stainless steel. A concave portion 5a is formed by machining in a bonding portion between the metal holder 5 and the ultrasonic vibrator 1. The dimensions of the recess 5a are the same width as the ultrasonic vibrator 1 and the protection plate 2, that is, the dimensions matching the shape of the vibrator 1. Thereby, since the ultrasonic transducer | vibrator 1 fits into the recessed part 5a and does not move at the time of manufacture, the yield of the product at the time of manufacture can be prevented. The metal holder 5 may be made of other metals as long as the material has good corrosion resistance.
The metal holder 5 improves the sensitivity by moving the resonance frequency of the ultrasonic transducer 1 out of the range and using it for measurement of the subject. For example, when the ultrasonic transducer 1 has a thickness of 1 mm and a length and width of 3 mm × 15 mm, the resonance frequency is about 20,000 Hz. On the other hand, the frequency at which the ultrasonic probe is used for measurement is 40 kHz. If the resonance frequency of the structure in which the ultrasonic vibrator 1 and the metal holder 5 are bonded is made the same as the measurement frequency (40 kHz), the reverberation at the time of measurement is large and undesirable. On the other hand, by setting the resonance frequency of the structure in which the ultrasonic vibrator 1 and the metal holder 5 are bonded to twice the measurement frequency (40 kHz), that is, 80 kHz, reverberation during measurement can be reduced, In addition, the sensitivity can be improved as compared with the case where the ultrasonic transducer 1 is used as a single element. In order to set the resonance frequency of the structure in which the ultrasonic vibrator 1 and the metal holding body 5 are bonded to 80 kHz, the ultrasonic vibrator 1 has a thickness of 5 mm and a length and width of 11 mm × 12 mm. Become.

  Since the ultrasonic vibrator 1 and the protective plate 2 bonded to the metal holder 5 are bonded to the metal holder 5 with an epoxy resin on the surface, the ultrasonic vibrator 1 and the protection plate 2 can sufficiently withstand the contact pressure with the subject during measurement. . Therefore, even when the ultrasonic transducer 1 is pressed against the subject, it can be prevented from being destroyed.

  The ultrasonic transducer 1 bonded to the metal holder 5 is attached to the concave portion of the case 6 of the guide wave ultrasonic probe. As illustrated, the case 6 of the guide wave ultrasonic probe has a two-layer structure having an upper gap 7a and a lower gap 7b. In the case of the two-layer structure, the signal wiring 11 from the electrode 3 is arranged in the upper gap 7a, and the ultrasonic vibrator integrated with the metal holder 5 is attached to the lower gap 7b on one side of the metal holder 5 with the case 6. The ultrasonic probe is manufactured by adhering the surface with the adhesive 13. The upper part of the upper gap 7a is covered with a lid 14.

  Similar to the bonding of the metal holder 5 and the ultrasonic transducer 1, when the metal holder 5 is bonded to the lower space 7b of the case 6 of the guide wave ultrasonic probe, the metal holder 5 is prevented from moving. Since the step portion is processed and the movement preventing portion 12 is provided, it is possible to adhere to a certain position, so that it is possible to prevent the yield of products during manufacturing.

  Resins 9 are filled in the gaps 7a and 7b inside the case 6 of the guide wave ultrasonic probe without any gaps. The resin 9 has a role of reinforcing the ultrasonic vibrator 1 and attenuating the reverberation of the sound wave transmitted from the ultrasonic vibrator 1. The resin 9 to be filled is suitably a material such as an epoxy resin, an acrylic resin or polystyrene, which is an insulating curable material.

  The lead wire 11 bonded or soldered to the electrode 3 of the ultrasonic transducer 1 is pulled out of the case 6 through the wiring hole 10 as it is.

  As described above, according to the present embodiment, since the ultrasonic transducer is surface-bonded to the metal holder, the ultrasonic transducer can sufficiently withstand the contact pressure with the subject during measurement. Even when 1 is pressed against the subject, it can be prevented from being destroyed.

  In addition, since the gap between the guide wave ultrasonic probe and the holder inside the case is filled with resin, the reverberation of the sound wave transmitted from the ultrasonic transducer can be attenuated. .

  Further, since the optimum resonance frequency can be selected as the resonance frequency of the ultrasonic transducer and the holding body, the sensitivity can be improved.

  In addition, by forming a concave groove in the holder, the surface of the protection plate of the ultrasonic transducer can be bonded to the holder completely face-to-face, so an ultrasonic probe that is resistant to pressure contact with the subject. You can get a child.

  In addition, in the gap of the ultrasonic probe case, an insulating curable resin is filled in the gap created by attaching the ultrasonic transducer, the holding body, and the signal wiring so that no bubbles are mixed. As a result, the holding body and the ultrasonic vibrator can be integrally covered, so that the connection portion between the ultrasonic vibrator and the electric wiring can be protected and strong against external impact.

Next, the configuration of an ultrasonic probe according to the second embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a cross-sectional view showing a configuration of an ultrasonic probe according to the second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts. 2A is a front sectional view, and FIG. 2B is a side sectional view.

  In the present embodiment, the guided wave ultrasonic probe case 6A has a single-layer structure rather than a two-layer structure. In this embodiment, since the holding body 5 is the same as that shown in FIG. 1, the height of the case 6A can be made lower than that of the case 6 shown in FIG. 1, and the ultrasonic probe can be made thin. can do.

  According to this embodiment, since the ultrasonic transducer is surface-bonded to the metal holder, it can sufficiently withstand the contact pressure with the subject during measurement, and the ultrasonic transducer 1 is pressed against the subject. Even if it does, it can be prevented from being destroyed.

  In addition, since the gap between the guide wave ultrasonic probe and the holder inside the case is filled with resin, the reverberation of the sound wave transmitted from the ultrasonic transducer can be attenuated. .

  Further, since the optimum resonance frequency can be selected as the resonance frequency of the ultrasonic transducer and the holding body, the sensitivity can be improved.

  In addition, in the gap of the ultrasonic probe case, an insulating curable resin is filled in the gap created by attaching the ultrasonic transducer, the holding body, and the signal wiring so that no bubbles are mixed. As a result, the holding body and the ultrasonic vibrator can be integrally covered, so that the connection portion between the ultrasonic vibrator and the electric wiring can be protected and strong against external impact.

  Furthermore, the ultrasonic probe can be made thin.

Next, the configuration of an ultrasonic probe according to the third embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a cross-sectional view of the main part showing the configuration of an ultrasonic probe according to the third embodiment of the present invention. That is, FIG. 3 is an enlarged view of the lower half of the structure shown in FIG. The same reference numerals as those in FIG. 1 indicate the same parts. 3A is a front cross-sectional view of the main part, and FIG. 3B is a side cross-sectional view of the main part.

  In the present embodiment, the metal holder 5B is formed with a convex portion 5b at a portion (lower side in the figure) to which the ultrasonic transducer 1 is attached. This is effective when the shape of the ultrasonic vibrator 1 is smaller than that of the metal holder 5B (when the width of the ultrasonic vibrator 1 in the left-right direction in FIG. 3B is smaller than that of the holder 5B). . That is, it is possible to prevent conduction between the positive electrode 3 and the negative electrode 3 of the ultrasonic transducer 1 to which the lead wire 11 is attached in contact with the metal holder 5B. The height of the convex portion 5b of the metal holder 5B is higher than the height of the solder 4 and the adhesive. Further, in order to prevent the ultrasonic transducer 1 from moving at the time of manufacture, the bonding portion of the metal holder 5B matches the groove of the same width as the ultrasonic transducer 1 and the protective plate 2, that is, the shape of the transducer 1. The yield of the product at the time of manufacture can be prevented by forming the recess 5a by machining.

  According to this embodiment, since the ultrasonic transducer is surface-bonded to the metal holder, it can sufficiently withstand the contact pressure with the subject during measurement, and the ultrasonic transducer 1 is pressed against the subject. Even if it does, it can be prevented from being destroyed.

  In addition, since the gap between the guide wave ultrasonic probe and the holder inside the case is filled with resin, the reverberation of the sound wave transmitted from the ultrasonic transducer can be attenuated. .

  Further, since the optimum resonance frequency can be selected as the resonance frequency of the ultrasonic transducer and the holding body, the sensitivity can be improved.

  In addition, in the gap of the ultrasonic probe case, an insulating curable resin is filled in the gap created by attaching the ultrasonic transducer, the holding body, and the signal wiring so that no bubbles are mixed. As a result, the holding body and the ultrasonic vibrator can be integrally covered, so that the connection portion between the ultrasonic vibrator and the electric wiring can be protected and strong against external impact.

  Furthermore, even when the ultrasonic probe is small, it is possible to prevent the electrode from contacting the metal holder and conducting.

Next, the configuration of an ultrasonic probe according to the fourth embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a cross-sectional view showing a configuration of an ultrasonic probe according to the fourth embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts. 4A is a front sectional view, and FIG. 4B is a side sectional view.

  In the present embodiment, the connection connector 8 is attached to the upper gap 7a of the two-layer guided wave ultrasonic probe case 6 shown in FIG. The lead wire 11 from the electrode 3 is also connected to the connection connector 8 so that the lead wire 11 can be easily connected to the outside. Depending on the specifications of the connection connector 8, the connection connector 8 may occupy the entire area of the upper gap 7a. In this respect, the two-layer structure is effective. Further, the provision of the connection connector 8 has an advantage that even if the guide wave ultrasonic probe becomes defective, the lead wire 11 does not need to be cut and connected and can be easily replaced.

  According to this embodiment, since the ultrasonic transducer is surface-bonded to the metal holder, it can sufficiently withstand the contact pressure with the subject during measurement, and the ultrasonic transducer 1 is pressed against the subject. Even if it does, it can be prevented from being destroyed.

  In addition, since the gap between the guide wave ultrasonic probe and the holder inside the case is filled with resin, the reverberation of the sound wave transmitted from the ultrasonic transducer can be attenuated. .

  Further, since the optimum resonance frequency can be selected as the resonance frequency of the ultrasonic transducer and the holding body, the sensitivity can be improved.

  In addition, in the gap of the ultrasonic probe case, an insulating curable resin is filled in the gap created by attaching the ultrasonic transducer, the holding body, and the signal wiring so that no bubbles are mixed. As a result, the holding body and the ultrasonic vibrator can be integrally covered, so that the connection portion between the ultrasonic vibrator and the electric wiring can be protected and strong against external impact.

  Furthermore, connection with the outside can be facilitated.

Next, the main configuration of an ultrasonic probe according to the fifth embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a cross-sectional view of the main part showing the configuration of an ultrasonic probe according to the fifth embodiment of the present invention. That is, FIG. 3 is an enlarged view of the lower half of the structure shown in FIG. The same reference numerals as those in FIG. 1 indicate the same parts. 5A is a front cross-sectional view of the main part, and FIG. 5B is a side cross-sectional view of the main part.

  This embodiment is provided on the surface of the electrode 3 of the ultrasonic transducer 1 and protrudes in the direction of the subject 15 as a protective plate 2 a that contacts the surface of the subject 15 among the protective plates 2 that protect the electrode 3. The shape has a shape curvature.

  The subject 15 is a cylindrical rod such as a pipe. When the diameter of the cylindrical rod is small (for example, 300 mmφ or less), the contact surface can be made almost constant because the protective plate on the plane and the surface of the subject 15 are in linear contact. However, when the diameter of the cylindrical rod increases (for example, 300 mmφ or more), the surface of the cylindrical rod becomes closer to a flat surface, so that the contact position between the protective plate and the subject 15 is likely to change. Thus, when the curvature radius of the surface of the subject 15 is large, the contact position between the protection plate 2a and the subject 15 can be made substantially constant by forming the protective plate 2a as a convex shape as shown in the figure. .

  Further, since the contact area with the subject 15 can be reduced and the pressure at the contact portion is increased, the transmission / reception signal of the ultrasonic transducer 1 is easily propagated to the subject 15.

  According to this embodiment, since the ultrasonic transducer is surface-bonded to the metal holder, it can sufficiently withstand the contact pressure with the subject during measurement, and the ultrasonic transducer 1 is pressed against the subject. Even if it does, it can be prevented from being destroyed.

  In addition, since the gap between the guide wave ultrasonic probe and the holder inside the case is filled with resin, the reverberation of the sound wave transmitted from the ultrasonic transducer can be attenuated. .

  Further, since the optimum resonance frequency can be selected as the resonance frequency of the ultrasonic transducer and the holding body, the sensitivity can be improved.

  In addition, in the gap of the ultrasonic probe case, an insulating curable resin is filled in the gap created by attaching the ultrasonic transducer, the holding body, and the signal wiring so that no bubbles are mixed. As a result, the holding body and the ultrasonic vibrator can be integrally covered, so that the connection portion between the ultrasonic vibrator and the electric wiring can be protected and strong against external impact.

  Furthermore, the contact position between the protective plate and the subject can be made substantially constant.

Further, the contact area with the subject can be reduced, and the transmission / reception signal of the ultrasonic transducer is easily propagated to the subject, so that the sensitivity can be improved.

It is sectional drawing which shows the structure of the ultrasonic probe by the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the ultrasonic probe by the 2nd Embodiment of this invention. It is principal part sectional drawing which shows the structure of the ultrasonic probe by the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the ultrasonic probe by the 4th Embodiment of this invention. It is principal part sectional drawing which shows the structure of the ultrasonic probe by the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic vibrator 2 ... Protection board 3 ... Electrode 4 ... Solder adhesion part 5 ... Metal holding body 6 ... Case 7 ... Air gap 8 ... Connection connector 9 ... Resin 10 ... Wiring hole 11 ... Lead wire 12 ... Movement prevention part 13 ... surface bonding part 14 ... lid 15 ... subject

Claims (3)

An ultrasonic probe having an ultrasonic transducer, electrodes formed on both surfaces of the ultrasonic transducer, and a protective plate for protecting the electrode,
A metallic rectangular parallelepiped holding body that is bonded to one of the protective plates and changes the resonance frequency of the structure formed by being bonded to the ultrasonic transducer from the measurement frequency. ,
A case having a recess for storing the holding body, and attaching and fixing the holding body in the recess;
An ultrasonic probe comprising: an insulating curable resin filled in a gap between the concave portion of the case and the holding body. The ultrasonic probe according to claim 1,
The ultrasonic probe according to claim 1, wherein a surface of the protective plate that contacts the subject has a convex shape in the direction of the subject. The ultrasonic probe according to claim 1,
The ultrasonic probe according to claim 1, wherein the holding body is formed with a concave portion matching a shape of the ultrasonic transducer and the protective plate at a portion where the ultrasonic transducer and the protective plate are attached.

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