JP2013127400A - Ultrasonic inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely inspect an end of an object of inspection by suppressing a diffracted wave bypassing the object of inspection and reaching an ultrasonic reception device.SOLUTION: An ultrasonic wave shield member 54 having a plate-like member 56 and an elastic member 58 is provided in contact with an end face of an object 30 of inspection more on an outer peripheral side than an ultrasonic wave transmission position. The elastic member 58 comes into contact with the end face of the object 30 of inspection while elastically deforming so as to prevent an ultrasonic wave from leaking through a gap between the end face of the object 30 of inspection and the elastic member 58. The ultrasonic wave shield member 54 in contact with the end face of the object 30 of inspection can suppress an ultrasonic wave transmitted from an ultrasonic wave transmission surface 12 from bypassing the object 30 of inspection and reaching an ultrasonic wave reception surface 22 as a diffracted wave.

Description

  The present invention relates to an ultrasonic inspection apparatus that inspects an inspection object using ultrasonic waves.

  As means for performing non-destructive evaluation of materials, techniques using radiation, electromagnetics, ultrasonic waves, and the like are used according to applications. Among them, ultrasonic waves are widely used as a method that can be easily introduced at production sites and the like because they have little influence on the human body and can inspect materials.

  However, in order to receive ultrasonic waves from inside the solid material and to receive ultrasonic waves from the inside of the solid material, conventionally, a coupling agent such as water or gel must be used between the material and the ultrasonic sensor. It was. Therefore, even for inspections on the production line, it is necessary to immerse the entire inspection object in water (water immersion method) or to spray water between the ultrasonic sensor and the inspection object only (partial immersion method). Yes, its application was limited to steel lines.

  In recent years, an aerial ultrasonic sensor has been developed that can receive high-accuracy ultrasonic waves in the air, enter the material, propagate through the material, and then receive the ultrasonic waves leaking from the material with high sensitivity (see below for the aerial ultrasonic method). Patent References 1 to 6). In the air, the higher the frequency, the higher the attenuation. Therefore, the frequency band is limited to a frequency band lower than the frequency band (1 MHz to 100 MHz) that can be used by the water immersion method, but it is desirable to use a frequency band as high as possible in order to improve inspection resolution. The frequency band of the developed aerial ultrasonic sensor is about 50 kHz to 1 MHz. Although high spatial resolution as high as the water immersion method cannot be expected, it is possible to inspect without contact, so it can be expected to be applied to 100% inspection in the line.

JP 2008-128965 A JP 2002-195987 A Japanese Patent No. 4120969 JP 2006-138818 A JP 2009-150692 A JP 2010-25817 A JP-A-8-21892 Japanese Patent No. 3480311 Japanese Patent No. 3036632 JP-A-8-313502 JP-A-64-73250

  As a technique for inspecting an inspection object using ultrasonic waves, for example, as in Patent Document 1, ultrasonic waves are transmitted from an ultrasonic transmission device arranged on the surface side of the inspection object, and transmitted through the inspection object. There is a transmission method in which the ultrasonic wave is received by an ultrasonic receiving device arranged on the back side of the inspection object. However, when the end of the inspection object is inspected by the transmission method, the ultrasonic wave received by the ultrasonic receiver is only transmitted waves that pass through the inspection object and reach the ultrasonic receiver. There is also a diffracted wave that bypasses the inspection target and reaches the ultrasonic receiver. This diffracted wave is received by the ultrasonic receiving device at approximately the same time as the transmitted wave, and further, the closer the ultrasonic transmitting device and the ultrasonic receiving device are to the side surface of the inspection object, the higher the reception level at the ultrasonic receiving device. Easy to grow. In order to accurately inspect the end of the inspection object, it is necessary to accurately detect the amplitude of the transmitted wave that passes through the inspection object and reaches the ultrasonic receiver from the received signal at the ultrasonic receiver. For this purpose, it is desirable to suppress diffracted waves that reach the ultrasonic receiving device by bypassing the inspection object.

  An object of the present invention is to accurately inspect an end portion of an inspection object by suppressing a diffracted wave that reaches the ultrasonic receiving device by bypassing the inspection object.

  The ultrasonic inspection apparatus according to the present invention employs the following means in order to achieve the above-described object.

  An ultrasonic inspection apparatus according to the present invention is an ultrasonic transmission surface that is disposed opposite to a surface end portion of an inspection object, and includes an ultrasonic transmission surface that transmits ultrasonic waves to the surface end portion of the inspection object. An ultrasonic wave receiving device and an ultrasonic wave receiving surface that is arranged to face the back surface end of the inspection object so as to face the ultrasonic wave transmission surface through the inspection object, and is transmitted from the ultrasonic transmission surface and inspected An ultrasonic receiving device including an ultrasonic receiving surface that receives ultrasonic waves transmitted through the inside, and an ultrasonic shielding member that is in close contact with the end surface on the outer peripheral side of the ultrasonic transmission position in the inspection object, from the ultrasonic transmitting surface The gist of the present invention is to include an ultrasonic shielding member for suppressing the transmitted ultrasonic wave from reaching the ultrasonic wave reception surface by bypassing the inspection object.

  In one aspect of the present invention, it is preferable that the portion of the ultrasonic shielding member that is in close contact with the end face of the inspection object is elastically deformable.

  In one embodiment of the present invention, it is preferable that the ultrasonic transmittance of the ultrasonic shielding member is lower than the ultrasonic transmittance of the inspection object.

  In one aspect of the present invention, it is preferable to include a pressing mechanism that presses the ultrasonic shielding member against the end surface of the inspection object.

  In one aspect of the present invention, a scanning device that moves an ultrasonic transmission device and an ultrasonic reception device so as to move an ultrasonic transmission position in an inspection object is provided, and the ultrasonic shielding member includes an ultrasonic wave in the inspection object. It is preferable to make close contact with the outer peripheral end surface over the entire movement range of the transmission position.

  In one aspect of the present invention, the scanning device includes a scanning device that moves the ultrasonic transmitting device and the ultrasonic receiving device so as to move the ultrasonic transmission position in the inspection target, and the ultrasonic shielding member is the inspection target. It is preferable to move the ultrasonic shielding member together with the ultrasonic transmission device and the ultrasonic reception device so as to maintain a state of being in close contact with the end face on the outer peripheral side from the ultrasonic transmission position.

  In one aspect of the present invention, the inspection object is such that the first plate-like member and the second plate-like member are bonded to each other through the adhesive layer at the end, and the ultrasonic transmission surface is the surface of the first plate-like member. The ultrasonic wave is transmitted to the adhesive layer through the first plate member, and the ultrasonic wave receiving surface is ultrasonically transmitted through the first plate member, the adhesive layer, and the second plate member. The ultrasonic wave transmitted from the ultrasonic transmission surface and transmitted through the first plate member, the adhesive layer, and the second plate member is received so as to face the back surface end of the second plate member so as to face the surface, It is preferable that the ultrasonic shielding member is in close contact with one or more of an end face on the outer peripheral side from the ultrasonic transmission position in the first plate member and an end face on the outer peripheral side from the ultrasonic transmission position in the second plate member. is there.

  According to the present invention, when the end of the inspection object is inspected, the ultrasonic wave transmitted from the ultrasonic transmission surface is prevented from bypassing the inspection object and reaching the ultrasonic reception surface as a diffracted wave. Therefore, the amplitude of the transmitted wave that passes through the inspection object and reaches the ultrasonic wave reception surface can be accurately detected from the reception signal on the ultrasonic wave reception surface. As a result, the end of the inspection object can be inspected with high accuracy.

1 is a diagram showing a schematic configuration of an ultrasonic inspection apparatus according to an embodiment of the present invention. 1 is a diagram showing a schematic configuration of an ultrasonic inspection apparatus according to an embodiment of the present invention. 1 is a diagram showing a schematic configuration of an ultrasonic inspection apparatus according to an embodiment of the present invention. It is a figure explaining the propagation path of the ultrasonic wave from an ultrasonic transmission surface to an ultrasonic reception surface. When the ultrasonic wave transmitted from the ultrasonic wave transmitting surface is received by the ultrasonic wave receiving surface while moving the ultrasonic wave transmitting surface and the ultrasonic wave receiving surface to change the focal position x, the measured ultrasonic signal It is a figure which shows distribution of an amplitude maximum value. It is a figure explaining the position x of the focus with respect to a test subject. The ultrasonic signal waveform measured when the ultrasonic wave transmitted from the ultrasonic wave transmitting surface is received by the ultrasonic wave receiving surface while moving the ultrasonic wave transmitting surface and the ultrasonic wave receiving surface to change the focal point position x. It is a figure which shows an example. The ultrasonic signal waveform measured when the ultrasonic wave transmitted from the ultrasonic wave transmitting surface is received by the ultrasonic wave receiving surface while moving the ultrasonic wave transmitting surface and the ultrasonic wave receiving surface to change the focal point position x. It is a figure which shows an example. It is a figure which shows the other schematic structure of the ultrasonic inspection apparatus which concerns on embodiment of this invention. It is a figure which shows the other schematic structure of the ultrasonic inspection apparatus which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  1 to 3 are diagrams showing a schematic configuration of an ultrasonic inspection apparatus according to an embodiment of the present invention, FIGS. 1 and 2 show a schematic configuration of the entire apparatus, and FIG. 3 is an ultrasonic transmission sensor 10 and an ultrasonic reception. A schematic configuration of the sensor 20 is shown. The ultrasonic inspection apparatus according to this embodiment includes an ultrasonic transmission sensor 10, an ultrasonic reception sensor 20, an ultrasonic shielding member 54, a scanning device 40, an ultrasonic signal supply unit 41, and a signal processing unit 42. , An image processing unit 44, a display device 46, and an inspection determination unit 48.

  The inspection object 30 is configured to include steel plates 32 and 34 that are plate-like members and an adhesive layer 36 for joining the steel plates 32 and 34 at the ends, and the back end portion 32b of the steel plate 32 and the steel plate 34. The surface end portion 34 a of the first and second surfaces are joined through an adhesive layer 36. A region where the adhesive layer 36 is not provided between the steel plates 32 and 34 is a gap. In the following description, as an application example of the inspection of the inspection object 30 using the ultrasonic inspection apparatus according to the present embodiment, a case where the adhesion by the adhesive layer 36 of the steel plates 32 and 34 is evaluated will be described.

  The ultrasonic transmission sensor 10 includes an ultrasonic transmission surface 12 disposed to face the surface end portion 32a of the inspection object 30 (steel plate 32) so as to face the adhesive layer 36 through the steel plate 32, and a transmission-side ultrasonic shielding cap. 14. The ultrasonic transmission surface 12 can be constituted by, for example, a piezoelectric element. An ultrasonic signal from the ultrasonic signal supply unit 41 is supplied to the ultrasonic transmission sensor 10. The ultrasonic transmission sensor 10 transmits an ultrasonic wave from the ultrasonic transmission surface 12 to the surface end portion 32 a of the steel plate 32 based on the ultrasonic signal supplied from the ultrasonic signal supply unit 41. The ultrasonic wave transmitted from the ultrasonic transmission surface 12 propagates in the air and enters the surface end portion 32a of the steel plate 32 as indicated by an arrow 61 in FIG. The ultrasonic wave incident on the surface end portion 32a of the steel plate 32 passes through the steel plate 32 and reaches the adhesive layer 36, and further passes through the adhesive layer 36 and the steel plate 34 for inspection as shown by the arrow 62 in FIG. It reaches the back side of the object 30 (steel plate 34). In the example shown in FIGS. 1 and 3, the ultrasonic transmission sensor 10 is a focus type sensor, and the ultrasonic transmission surface 12 has a concave curved surface shape in which the focal point 38 is located in the inspection object 30 (adhesive layer 36). The ultrasonic waves transmitted from the ultrasonic transmission surface 12 are focused on the focal point 38 (adhesive layer 36). The configuration of the transmission side ultrasonic shielding cap 14 will be described later.

  The ultrasonic receiving sensor 20 is disposed so as to face the back end 34b of the inspection object 30 (steel plate 34) so as to face the ultrasonic transmission surface 12 via the inspection object 30 (steel plate 32, adhesive layer 36, and steel plate 34). An ultrasonic receiving surface 22 and a receiving-side ultrasonic shielding cap 24 are configured. The ultrasonic receiving surface 22 can also be configured by, for example, a piezoelectric element. The ultrasonic wave that has reached the back side of the inspection object 30 (steel plate 34) propagates in the air and reaches the ultrasonic wave receiving surface 22 as indicated by an arrow 63 in FIG. The ultrasonic reception sensor 20 receives ultrasonic waves transmitted from the ultrasonic transmission surface 12 and transmitted through the inspection object 30 (the steel plate 32, the adhesive layer 36, and the steel plate 34) by the ultrasonic reception surface 22. In the example shown in FIGS. 1 and 3, the ultrasonic reception sensor 20 is also a focus type sensor, and the ultrasonic reception surface 22 has a concave curved surface shape in which the focal point 38 is located in the inspection object 30 (adhesive layer 36). The ultrasonic waves focused on the focal point 38 diffuse and reach the entire ultrasonic receiving surface 22. The configuration of the reception-side ultrasonic shielding cap 24 will be described later.

  The scanning device 40 causes the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 (the ultrasonic transmission surface 12 and the ultrasonic reception surface 22) to move and scan two-dimensionally in parallel with the plate surface directions of the steel plates 32 and 34. Thereby, the focal point 38 of the ultrasonic transmission surface 12 and the ultrasonic reception surface 22 can be moved and scanned two-dimensionally in parallel with the plate surface direction of the steel plates 32 and 34 with respect to the inspection target object 30. The ultrasonic transmission position (adhesion evaluation position) with respect to 30 can be moved and scanned two-dimensionally in parallel with the plate surface direction of the steel plates 32 and 34. When evaluating the adhesion of the steel plates 32 and 34 by the adhesive layer 36, ultrasonic waves are transmitted from the ultrasonic transmission sensor 10 while two-dimensionally moving and scanning the ultrasonic transmission position with respect to the inspection object 30 by the scanning device 40. The ultrasonic wave reception sensor 20 receives the ultrasonic wave transmitted and transmitted through the inspection object 30. At that time, by using the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 as focus type sensors, the spatial resolution of the adhesion evaluation position with respect to the inspection object 30 can be improved.

  The signal processing unit 42 detects the amplitude of the ultrasonic signal corresponding to each ultrasonic transmission position (adhesion evaluation position) received by the ultrasonic reception sensor 20 (ultrasonic reception surface 22). The image processing unit 44 images the amplitude of the ultrasonic signal detected by the signal processing unit 42 in a two-dimensional plane in association with each ultrasonic transmission position, and causes the display device 46 to display the two-dimensional image. The inspection determination unit 48 evaluates the adhesion of the steel plates 32 and 34 by the adhesive layer 36 based on the amplitude of the ultrasonic signal corresponding to each ultrasonic transmission position detected by the signal processing unit 42. The object 30 is inspected. For example, when there is peeling at the interface between the steel plate 32 (or the steel plate 34) and the adhesive layer 36, the inspection object 30 (the steel plate 32, the adhesive layer 36, and the steel plate 34) is transmitted through compared with the case where there is no peeling. The level of the ultrasonic signal received by the ultrasonic receiving surface 22 decreases. Therefore, it is possible to evaluate the adhesion of the steel plates 32 and 34 by the adhesive layer 36 by examining the amplitude of the ultrasonic wave received by the ultrasonic wave receiving surface 22 and corresponding to each ultrasonic wave transmitting position.

  When evaluating the adhesion by the adhesive layer 36 at the ends of the steel plates 32 and 34, the ultrasonic wave is transmitted from the ultrasonic transmission surface 12 toward the surface end portion 32a of the steel plate 32, and from the back end portion 34b of the steel plate 34. Are received by the ultrasonic wave receiving surface 22. At that time, most of the ultrasonic energy transmitted from the ultrasonic transmission sensor 10 (focus type sensor) is focused toward the focal point 38 as shown by arrows 61 and 62 in FIG. As shown by an arrow 64 in FIG. 4, a diffracted wave propagates in the air in a direction spreading from the sensor, and as shown by arrows 65 and 66 in FIG. To do. As a result, the ultrasonic wave received by the ultrasonic wave receiving surface 22 is transmitted through the inspection object 30 (the steel plate 32, the adhesive layer 36, and the steel plate 34) as shown by arrows 61 to 63 in FIG. In addition to the transmitted wave reaching the sound wave receiving surface 22, in practice, as shown by arrows 64 to 66 in FIG. 4, the ultrasonic wave bypasses the inspection object 30 (the steel plate 32, the adhesive layer 36 and the steel plate 34). There is also a diffracted wave that reaches the receiving surface 22. This diffracted wave is received by the ultrasonic wave receiving surface 22 at substantially the same time as the transmitted wave, and further, the ultrasonic wave transmitting surface 12 and the ultrasonic wave receiving surface 22 are passed through the end surfaces of the inspection object 30 (the end surfaces 32c of the steel plates 32 and 34, 34c), the reception level at the ultrasonic wave receiving surface 22 tends to increase. In order to accurately evaluate the adhesion due to the adhesive layer 36 at the ends of the steel plates 32 and 34, the amplitude of the transmitted wave that passes through the inspection object 30 and reaches the ultrasonic receiving surface 22 is defined as the ultrasonic receiving surface 22. Therefore, it is desirable to suppress the diffracted wave that reaches the ultrasonic wave receiving surface 22 by bypassing the inspection object 30. In particular, when the inspection object 30 has a three-layer structure such as the steel plate 32, the adhesive layer 36, and the steel plate 34, the energy of the ultrasonic wave that passes through the region becomes very small. Even if a diffracted wave with a slight energy is mixed, the adhesion evaluation is greatly affected.

  Therefore, in the present embodiment, in order to suppress the ultrasonic wave transmitted from the ultrasonic transmission surface 12 from reaching the ultrasonic reception surface 22 by bypassing the inspection target 30, A plate-like ultrasonic shielding member 54 is provided in close contact with the end face on the outer peripheral side from the ultrasonic transmission position (adhesion evaluation position). The ultrasonic shielding member 54 includes a plate-like member 56 and an elastically deformable elastic member 58 provided on one end surface of the plate-like member 56. One end face (elastic member 58) of the plate-like member 56 is formed along the end face shape on the outer peripheral side from the moving range 71 of the ultrasonic transmission position (adhesion evaluation position) in the inspection object 30, and the elastic member 58 is inspected. The ultrasonic wave transmission position moving range 71 of the object 30 is in close contact with the outer peripheral end surfaces (end surfaces 32c, 34c of the steel plates 32, 34). At that time, the elastic member 58 is in close contact with the end surface of the inspection object 30 while being elastically deformed, thereby preventing ultrasonic waves from leaking through the gap between the end surface of the inspection object 30 and the elastic member 58. Is done. A spring 60 as a pressing mechanism is provided on the other end surface of the plate-like member 56, and the ultrasonic shielding member 54 is supported by the jig 70 via the spring 60. The ultrasonic shielding member 54 is pressed against the end surface of the inspection object 30 by the urging force of the spring 60, so that an adhesion force can be stably generated between the end surface of the inspection object 30 and the elastic member 58. In the example shown in FIG. 1, the elastic member 58 is in close contact with both of the end faces 32 c and 34 c on the outer peripheral side from the ultrasonic transmission position in the steel plates 32 and 34, but the elastic member 58 is in the outer periphery from the ultrasonic transmission position in the steel plate 32. The elastic member 58 may be in close contact with only the end surface 34c on the outer peripheral side of the ultrasonic wave transmitting position in the steel plate 34.

  In order to suppress the diffracted wave component that bypasses the inspection object 30, it is preferable to reduce the ultrasonic transmittance of the ultrasonic shielding member 54. For example, the ultrasonic transmittance of the ultrasonic shielding member 54 is the inspection object. It is preferably lower than the transmittance of ultrasonic waves at 30. In order to reduce the ultrasonic transmittance of the ultrasonic shielding member 54, a material with high acoustic impedance is used for the ultrasonic shielding member 54, or a material with a high ultrasonic attenuation rate is used for the ultrasonic shielding member 54. In addition, it is preferable to increase the thickness of the ultrasonic shielding member 54. Further, the path from the ultrasonic transmission surface 12 to the ultrasonic reception surface 22 bypassing the inspection object 30 and the ultrasonic shielding member 54 is compared with the distance between the ultrasonic transmission surface 12 and the ultrasonic reception surface 22. Therefore, it is preferable to determine the width of the ultrasonic shielding member 54 so as to be sufficiently long (for example, twice or more).

  Further, the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 are respectively provided with a transmission-side ultrasonic shielding cap 14 and a reception-side ultrasonic shielding cap 24 for shielding ultrasonic waves. As shown in FIGS. 1 and 3, the transmission-side ultrasonic shielding cap 14 surrounds the entire circumference of the ultrasonic transmission surface 12, and the inspection object 30 (steel plate 32) is surrounded by the periphery of the ultrasonic transmission surface 12. A through-hole 14c for propagating ultrasonic waves in the air from the ultrasonic transmission surface 12 to the surface end portion 32a of the steel plate 32 is provided on the ultrasonic transmission surface 12 side. It is formed from the end portion to the end portion on the surface side of the steel plate 32. A slight gap (for example, about 3 to 4 mm) is formed between the distal end surface 14b of the transmission-side ultrasonic shielding cap 14 and the surface end portion 32a of the inspection object 30 (steel plate 32). Alternatively, the front end surface 14 b of the transmission-side ultrasonic shielding cap 14 can be brought into contact with the surface end portion 32 a of the steel plate 32.

  In order to accurately extract only the component focused on the focal point 38 while suppressing the spreading diffracted wave component from the ultrasonic wave receiving surface 22, the transmission side ultrasonic wave shielding cap 14 is increased by increasing the thickness of the transmission side ultrasonic wave shielding cap 14. It is preferable to increase the attenuation amount of the ultrasonic wave in 14. Further, the inner peripheral surface 14a of the through hole 14c of the transmission-side ultrasonic shielding cap 14 has an outer periphery than the conical surface 12a that connects the outer periphery of the ultrasonic transmission surface 12 and the focal point 38 so as not to block the component that is focused on the focal point 38. It is preferable that the distance between the conical surface 12a and the inner peripheral surface 14a is shortened. For this purpose, the inner diameter of the transmission-side ultrasonic shielding cap 14 (the diameter of the through-hole 14c) is such that the surface side of the inspection object 30 (steel plate 32) (the lower side in FIGS. 1 and 3) is the ultrasonic transmission surface 12 side ( It is preferably smaller than the upper side of FIGS. In that case, for example, as shown in FIG. 3, as the inner circumferential surface 14 a is disposed close to the conical surface 12 a, the transmission-side ultrasonic wave is moved from the ultrasonic transmission surface 12 side toward the surface side of the inspection object 30. The inner diameter of the shielding cap 14 (the diameter of the through hole 14c) can be gradually reduced, and the transmission-side ultrasonic shielding cap 14 moves from the ultrasonic transmission surface 12 side toward the surface side of the inspection object 30. It is also possible to reduce the inner diameter in steps. Further, when the spread diffracted wave component is subjected to multiple reflection inside the transmission side ultrasonic shielding cap 14 (inner peripheral surface 14a), it causes noise. In order to suppress the multiple reflection of the diffracted wave on the inner peripheral surface 14a, it is preferable that the acoustic impedance of the transmission side ultrasonic shielding cap 14 is lower than the acoustic impedance of the inspection object 30 (steel plates 32, 34). For example, the material of the transmission-side ultrasonic shielding cap 14 can be made of resin (for example, polyacetal) or rubber having a lower acoustic impedance than a metal material.

  As shown in FIGS. 1 and 3, the reception-side ultrasonic shielding cap 24 surrounds the entire circumference of the ultrasonic reception surface 22, and the inspection object 30 (steel plate 34) is surrounded by the periphery of the ultrasonic reception surface 22. A through hole 24c for propagating ultrasonic waves in the air from the ultrasonic wave receiving surface 22 to the back surface edge portion 34b of the steel plate 34 is provided on the ultrasonic wave receiving surface 22 side. It is formed from the end portion to the end portion on the back surface side of the steel plate 34. A slight gap (for example, about 3 to 4 mm) is formed between the front end surface 24b of the reception-side ultrasonic shielding cap 24 and the surface end portion 34b of the inspection object 30 (steel plate 34). Alternatively, the front end surface 24 b of the reception-side ultrasonic shielding cap 24 can be brought into contact with the surface end portion 34 b of the steel plate 34.

  In order to accurately extract only the component that diffuses from the focal point 38 while suppressing the diffracted wave component that bypasses the inspection object 30, by increasing the thickness of the reception-side ultrasonic shielding cap 24, It is preferable to increase the attenuation amount of ultrasonic waves in the reception-side ultrasonic shielding cap 24. Further, the inner peripheral surface 24a of the through hole 24c of the reception-side ultrasonic shielding cap 24 is more peripheral than the conical surface 22a that connects the outer periphery of the ultrasonic reception surface 22 and the focal point 38 so as not to block components diffusing from the focal point 38. It is preferable that the distance between the conical surface 22a and the inner peripheral surface 24a is shortened. For this purpose, the inner diameter of the reception-side ultrasonic shielding cap 24 (the diameter of the through hole 24c) is such that the back side (upper side of FIGS. 1 and 3) of the inspection object 30 (steel plate 34) is the ultrasonic reception surface 22 side (see FIG. It is preferable to be smaller than (lower side of 1, 3). In that case, for example, as shown in FIG. 3, the reception-side ultrasonic wave is advanced from the sound-receiving / transmission surface 22 side toward the back surface side of the inspection object 30 so that the inner peripheral surface 24 a is disposed close to the conical surface 22 a. The inner diameter of the shielding cap 24 (the diameter of the through hole 24c) can be gradually reduced, and the reception-side ultrasonic shielding cap 24 moves from the ultrasonic receiving surface 22 side toward the back surface side of the inspection object 30. It is also possible to reduce the inner diameter in steps. In addition, if the ultrasonic waves are multiple-reflected inside the reception-side ultrasonic shielding cap 24 (inner peripheral surface 24a), it causes noise. In order to suppress the multiple reflection of the ultrasonic wave at the inner peripheral surface 24a, it is preferable that the acoustic impedance of the reception-side ultrasonic shielding cap 24 is also lower than the acoustic impedance of the inspection object 30 (steel plates 32 and 34). For example, the material of the reception-side ultrasonic shielding cap 24 can also be made of resin (for example, polyacetal) or rubber having a lower acoustic impedance than a metal material.

  Measured when the ultrasonic wave transmitted from the ultrasonic wave transmitting surface 12 is received by the ultrasonic wave receiving surface 22 while moving the ultrasonic wave transmitting surface 12 and the ultrasonic wave receiving surface 22 to change the position x of the focal point 38. The distribution of the maximum amplitude value of the ultrasonic signal is shown in FIG. In FIG. 5, the end face of the inspection object 30 is set to a position x = 0 mm, the outside of the inspection object 30 is set to a position x> 0 mm, and the inside of the inspection object 30 is set to a position x <0 mm (see FIG. 6). Then, the distribution of the maximum amplitude value of the ultrasonic signal between 100 μs and 150 μs is shown in the range of position x = −3 mm to 17 mm. In FIG. 5, (a) shows the result when the ultrasonic shielding member 54 is not provided, and (b) shows nitrile rubber (NBR, hardness Shore A66) on one end face of the acrylic resin plate-like member 56. (C) shows the result when a viscoelastic elastomer (hardness Asker F65) is provided on one end face of the acrylic resin plate-like member 56, and (d) shows the result made of acrylic resin. The result when a chloroprene rubber sponge (hardness Asker C20) is provided on one end surface of the plate-like member 56 is shown. Further, the ultrasonic signal waveforms at the position x = −3 mm and 17 mm in the case of (a) are shown in FIG. 7 (a) -1 and (a) -2, and the position x = −3 mm in the case of (b). , 1 mm, and 17 mm are shown in FIG. 7 (b) -1, (b) -2, and (b) -3, and in the case of (c), the position x = −3 mm, 4 mm, and 17 mm. (C) -1, (c) -2, and (c) -3 in FIG. 8, and the ultrasonic signal waveforms at positions x = -3 mm, 4 mm, and 17 mm in the case of (d). Are shown in (d) -1, (d) -2, and (d) -3 in FIG.

  In the case of (a) where the ultrasonic shielding member 54 is not provided, as shown in FIGS. 5 and 7, in the inspection object 30 at x = −3 mm where the focal point 38 is located in the inspection object 30 (adhesive layer 36). A diffracted wave was observed superimposed on the waveform transmitted through (the steel plate 32, the adhesive layer 36, and the steel plate 34), and the diffracted wave appeared greatly at a later time than the transmitted wave in the inspection object 30. Then, as the focal point 38 approaches the end face (position x = 0) of the inspection object 30, the amplitude of the ultrasonic signal is greatly influenced by the diffracted wave, and the frustoconical ultrasonic shielding caps 14 and 24 are increased. At a position x> 4 mm where all the tips appeared outside from the end face of the inspection object 30, the measured ultrasonic signal waveform became a saturated waveform as shown in FIG.

  In the case of (b) provided with nitrile rubber, a gap was formed between the nitrile rubber and the end face of the inspection object 30, and waves passing through the gap were measured. For example, a large waveform seen in a time zone of 150 μs or more in FIG. 7B or 130 μs or more in FIG. 7B-2 is a wave passing through the gap. Further, at x = 17 mm where the focal point 38 is located in the plate-like member 56 (acrylic resin), the wave transmitted through the plate-like member 56 was measured as shown in FIG.

  In the case of (c) provided with a viscoelastic elastomer, the waveform received by directly propagating through the air as seen in the cases of (a) and (b) was not measured. That is, it is considered that the gap between the viscoelastic elastomer and the end surface of the inspection object 30 could be completely filled because the viscoelastic elastomer was flexibly deformed. For this reason, when x = −3 mm where the focal point 38 is located in the inspection object 30 (adhesive layer 36), it is clear that it has been transmitted through the inspection object 30 as shown in FIG. I was able to obtain a simple waveform. However, at x = 4 mm where the focal point 38 is located in the viscoelastic elastomer, a larger waveform was measured as shown in FIG. This is a waveform transmitted through the viscoelastic elastomer, and is a result due to the fact that the viscoelastic elastomer is a material through which ultrasonic waves are more easily transmitted than the inspection object 30 (adhesive layer 36).

  In the case of (d) provided with a chloroprene rubber sponge, the waveform received by directly propagating through the air is not measured, and it can be seen that ultrasonic waves are not transmitted even at the position of the rubber sponge. For example, when x = −3 mm where the focal point 38 is located in the inspection object 30 (adhesive layer 36), the waveform other than the wave transmitted through the inspection object 30 is as shown in FIG. When x = 4 mm where the focal point 38 is not observed and the focal point 38 is located in the rubber sponge, no transmitted wave is measured as shown in (d) -2 of FIG. This is a result of the fact that the ultrasonic wave attenuates inside the porous rubber sponge, and the rubber sponge is a material through which the ultrasonic wave is harder to transmit than the inspection object 30 (adhesive layer 36).

  According to the present embodiment described above, when evaluating the adhesion by the adhesive layer 36 at the ends of the steel plates 32 and 34, the ultrasonic shielding member 54 that is in close contact with the end surfaces 32c and 34c of the steel plates 32 and 34 can be used. The ultrasonic wave transmitted from the sound wave transmitting surface 12 can be prevented from bypassing the inspection object 30 and reaching the ultrasonic wave receiving surface 22 as a diffracted wave. Therefore, the amplitude of the transmitted wave that passes through the inspection object 30 (the steel plate 32, the adhesive layer 36, and the steel plate 34) and reaches the ultrasonic wave receiving surface 22 is accurately detected from the received signal at the ultrasonic wave receiving surface 22. Can do. As a result, the adhesion by the adhesive layer 36 at the ends of the steel plates 32 and 34 can be accurately evaluated. In that case, when the elastic member 58 that is in close contact with the end surface of the inspection object 30 is made of an elastically deformable material such as a viscoelastic elastomer or rubber sponge, the end surface of the inspection object 30 has irregularities. Even so, it is possible to prevent the ultrasonic waves from leaking through the gap between the end face of the inspection object 30 and the ultrasonic shielding member 54 (elastic member 58), and to make diffraction that bypasses the inspection object 30. Wave components can be further suppressed. Furthermore, by pressing the ultrasonic shielding member 54 against the end surface of the inspection object 30 by the urging force of the spring 60, it is possible to stably generate a close contact force between the end surface of the inspection object 30 and the elastic member 58. . Further, by using a porous material having a high ultrasonic attenuation rate, such as a rubber sponge, as the material of the elastic member 58, the ultrasonic transmittance of the ultrasonic shielding member 54 can be made lower than that of the inspection object 30. Further, the diffracted wave component that bypasses the inspection object 30 can be further suppressed. Further, the transmission-side ultrasonic shielding cap 14 and the reception-side ultrasonic shielding cap 24 can further suppress the diffracted wave component that bypasses the inspection object 30.

  In the present embodiment, for example, as shown in FIG. 9, the ultrasonic shielding member 54 is sandwiched between the metal thin plates 72 and 74 and the end portions of the metal thin plates 72 and 74 and is elastically attached to the end surface of the inspection object 30. It is also possible to include the member 58. According to the configuration example shown in FIG. 9, by using the metal thin plates 72 and 74 having high acoustic impedance, the ultrasonic transmittance in the ultrasonic shielding member 54 can be lowered, and diffraction that bypasses the inspection object 30. Wave components can be further suppressed.

  Further, in the present embodiment, for example, as illustrated in FIG. 10, the ultrasonic shielding member 54 is supported by the scanning device 40 via the spring 60, so that the ultrasonic shielding member 54 is in an ultrasonic transmission position in the inspection object 30. It is also possible for the scanning device 40 to move the ultrasonic shielding member 54 together with the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 so as to maintain a state of being in close contact with the outer peripheral end surface. According to the configuration example shown in FIG. 10, it is not necessary for the ultrasonic shielding member 54 (elastic member 58) to be in close contact with the outer peripheral side end surface over the entire movement range 71 of the ultrasonic transmission position in the inspection object 30. The size of the ultrasonic shielding member 54 can be reduced. Also in the configuration example shown in FIG. 10, the path from the ultrasonic transmission surface 12 to the ultrasonic reception surface 22 bypassing the inspection object 30 and the ultrasonic shielding member 54 is the ultrasonic transmission surface 12 and the ultrasonic wave. It is preferable to determine the length and width of the ultrasonic shielding member 54 so as to be sufficiently long (for example, twice or more) as compared with the distance between the receiving surfaces 22.

  In the above description, the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 are focus sensors, and the ultrasonic transmission surface 12 and the ultrasonic reception surface 22 have a focal point 38 in the inspection object 30 (adhesive layer 36). The case of a concave curved surface shape has been described. However, in this embodiment, the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 may not be a focus type sensor, and for example, the ultrasonic transmission surface 12 and the ultrasonic reception surface 22 may be flat.

  In the above description, the case where the transmission-side ultrasonic shielding cap 14 and the reception-side ultrasonic shielding cap 24 are provided in the ultrasonic transmission sensor 10 and the ultrasonic reception sensor 20 has been described. However, in the present embodiment, only the transmission-side ultrasonic shielding cap 14 can be provided in the ultrasonic transmission sensor 10, or only the reception-side ultrasonic shielding cap 24 can be provided in the ultrasonic reception sensor 20. is there. Furthermore, in this embodiment, it is possible to omit both the transmission side ultrasonic shielding cap 14 and the reception side ultrasonic shielding cap 24. Even in those cases, the ultrasonic wave shielding member 54 can suppress the ultrasonic wave transmitted from the ultrasonic wave transmitting surface 12 from reaching the ultrasonic wave receiving surface 22 by bypassing the inspection object 30. is there.

  In the above description, as an application example of the inspection of the inspection object 30 using the ultrasonic inspection apparatus according to the present embodiment, the case of evaluating the adhesion by the adhesive layer 36 of the steel plates 32 and 34 has been described. However, the ultrasonic inspection apparatus according to the present embodiment can be applied to, for example, inspection of internal defects of the inspection object 30 in addition to the evaluation of the adhesion by the adhesive layer 36 of the steel plates 32 and 34.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  DESCRIPTION OF SYMBOLS 10 Ultrasonic transmission sensor, 12 Ultrasonic transmission surface, 14 Transmission side ultrasonic shielding cap, 20 Ultrasonic reception sensor, 22 Ultrasonic reception surface, 24 Reception side ultrasonic shielding cap, 30 Inspection object, 32, 34 Steel plate, 36 adhesive layer, 38 focus, 40 scanning device, 41 ultrasonic signal supply unit, 42 signal processing unit, 44 image processing unit, 46 display device, 48 inspection determination unit, 54 ultrasonic shielding member, 56 plate member, 58 elasticity Member, 60 spring, 70 jig, 72, 74 Metal thin plate.

Claims (7)

An ultrasonic transmission surface including an ultrasonic transmission surface that is disposed opposite to the surface end of the inspection object and transmits ultrasonic waves to the surface end of the inspection object; and
An ultrasonic receiving surface disposed opposite to the back end of the inspection object so as to face the ultrasonic transmission surface via the inspection object, and transmitted from the ultrasonic transmission surface and transmitted through the inspection object An ultrasonic receiving device including an ultrasonic receiving surface for receiving sound waves;
An ultrasonic shielding member that is in close contact with the outer peripheral end surface of the ultrasonic wave transmission position in the inspection object, and the ultrasonic wave transmitted from the ultrasonic wave transmission surface bypasses the inspection object and reaches the ultrasonic wave reception surface. An ultrasonic shielding member for suppressing
An ultrasonic inspection apparatus comprising: The ultrasonic inspection apparatus according to claim 1,
The ultrasonic inspection apparatus in which the portion of the ultrasonic shielding member that is in close contact with the end face of the inspection object is elastically deformable. The ultrasonic inspection apparatus according to claim 1 or 2,
The ultrasonic inspection apparatus, wherein the ultrasonic transmittance of the ultrasonic shielding member is lower than the ultrasonic transmittance of the inspection object. The ultrasonic inspection apparatus according to any one of claims 1 to 3,
An ultrasonic inspection apparatus comprising a pressing mechanism that presses an ultrasonic shielding member against the end face of an inspection object. The ultrasonic inspection apparatus according to any one of claims 1 to 4,
A scanning device for moving the ultrasonic transmission device and the ultrasonic reception device so as to move the ultrasonic transmission position in the inspection object;
The ultrasonic inspection apparatus, wherein the ultrasonic shielding member is in close contact with the outer peripheral end surface over the entire moving range of the ultrasonic transmission position in the inspection object. The ultrasonic inspection apparatus according to any one of claims 1 to 4,
A scanning device for moving the ultrasonic transmission device and the ultrasonic reception device so as to move the ultrasonic transmission position in the inspection object;
The scanning device moves the ultrasonic shielding member together with the ultrasonic transmission device and the ultrasonic reception device so as to maintain the state where the ultrasonic shielding member is in close contact with the end face on the outer peripheral side from the ultrasonic transmission position in the inspection object. Ultrasonic inspection device. The ultrasonic inspection apparatus according to any one of claims 1 to 6,
The inspection object has the first plate-like member and the second plate-like member joined to each other via an adhesive layer at the end,
The ultrasonic transmission surface is disposed opposite to the surface end of the first plate member, and transmits ultrasonic waves to the adhesive layer via the first plate member.
The ultrasonic wave receiving surface is arranged to face the back surface end of the second plate member so as to face the ultrasonic wave transmitting surface via the first plate member, the adhesive layer, and the second plate member, and from the ultrasonic wave transmitting surface. Receiving ultrasonic waves transmitted and transmitted through the first plate member, the adhesive layer and the second plate member;
The ultrasonic shielding member is in close contact with any one or more of an end face on the outer peripheral side from the ultrasonic transmission position in the first plate member and an end face on the outer peripheral side from the ultrasonic transmission position in the second plate member. apparatus.