Electromagnetic ultrasonic probe and electromagnetic ultrasonic inspection device

Abstract

To provide an electromagnetic ultrasonic probe capable of expanding an inspection range without adding a new device.SOLUTION: An electromagnetic ultrasonic probe comprises a magnetic field generation unit that generates a magnetic field whose magnetic flux direction alternates on a surface of a subject, and a coil that generates a current perpendicular to a magnetic flux change direction and parallel to the surface of the subject. The magnetic field generation unit has a plurality of magnets with different widths arranged in a direction parallel to the current generated by the coil. In an oblique angle flaw detection direction to be inspected, a width of the magnets arranged on a rear edge side is larger than a width of the magnets arranged on a front edge side along a direction in which a parallel component of an irradiated ultrasonic signal to the surface of the subject is positive.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electromagnetic ultrasonic probe and an electromagnetic ultrasonic inspection device for detecting defects occurring in welds of, for example, pressure vessels or piping in a non-contact manner. [Background technology]

[0002] In nuclear power plants, ultrasonic testing (UT) is performed on reactor pressure vessels (RPVs), recirculation piping, etc., to check for aging during their service life. Known ultrasonic testing techniques include electro-magnetic acoustic transducers (EMATs) that can perform ultrasonic testing without contacting the test object (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-318990 [Patent Document 2] JP 2022-103832 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in order to expand the inspection range of an electromagnetic ultrasonic probe having a conventional configuration, it is necessary to add devices such as a frequency and drive timing control device and a control device that varies the frequency of the transmission signal applied to the coil.

[0005] In order to solve the above-mentioned problems, the present invention provides an electromagnetic ultrasonic probe and an electromagnetic ultrasonic inspection device that can expand the inspection range without adding any new equipment.

[0006] The above and other objects of the present invention and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0007] The electromagnetic ultrasonic probe of the present invention includes a magnetic field generating unit that generates a magnetic field whose magnetic flux direction alternates on the surface of the object, and a coil that generates a current perpendicular to the magnetic flux change direction and parallel to the surface of the object. The magnetic field generating unit has a plurality of magnets with different widths arranged in a direction parallel to the current generated by the coil, and the width of the magnets arranged on the trailing edge side is greater than the width of the magnets arranged on the leading edge side in a direction in which the parallel component of the irradiated ultrasonic signal to the surface of the object is positive in the angle beam inspection direction to be inspected.

[0008] The electromagnetic ultrasonic probe of the present invention includes a magnetic field generating unit that generates a magnetic field whose magnetic flux direction alternates on a surface of a subject, and a coil that generates a current perpendicular to the magnetic flux change direction and parallel to the surface of the subject. The magnetic field generating unit has a plurality of magnets having different widths arranged in a direction perpendicular to the current generated by the coil.

[0009] Moreover, an electromagnetic ultrasonic inspection device according to the present invention includes any one of the electromagnetic ultrasonic probes described above, and an ultrasonic flaw detector that controls the electromagnetic ultrasonic probe to record a waveform signal. Effect of the Invention

[0010] According to the present invention, it is possible to widen the inspection range of an electromagnetic ultrasonic probe without adding a new device.

[0011] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating a configuration of an inspection device according to a first embodiment of the present invention. [Diagram 2]FIG. 1 is a top view illustrating a structure of an electromagnetic ultrasonic probe according to a first embodiment of the present invention. [Diagram 3] 1 is a side view illustrating a structure of an electromagnetic ultrasonic probe according to a first embodiment of the present invention. [Figure 4] FIG. 2 is a diagram for explaining an example of an ultrasonic wave generating method of the electromagnetic ultrasonic probe in the first embodiment of the present invention. [Diagram 5] FIG. 2 is a diagram for explaining an example of an ultrasonic wave generating method of the electromagnetic ultrasonic probe in the first embodiment of the present invention. [Figure 6] FIG. 4 is a diagram illustrating the structure of an electromagnetic ultrasonic probe according to a second embodiment of the present invention. [Figure 7] FIG. 4 is a top view illustrating the structure of an electromagnetic ultrasonic probe according to a second embodiment of the present invention. [Figure 8] FIG. 11 is a diagram illustrating the structure of an electromagnetic ultrasonic probe according to a third embodiment of the present invention. [Figure 9] 11A to 11C are diagrams illustrating an example of an ultrasonic wave generating method for an electromagnetic ultrasonic probe according to a third embodiment of the present invention. [Figure 10] FIG. 11 is a diagram illustrating the structure of an electromagnetic ultrasonic probe according to a fourth embodiment of the present invention. [Figure 11] FIG. 11 is a top view illustrating the structure of an electromagnetic ultrasonic probe according to a fourth embodiment of the present invention. [Figure 12] FIG. 11 is a side view illustrating the structure of an electromagnetic ultrasonic probe according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An example of an electromagnetic ultrasonic probe and an electromagnetic ultrasonic inspection device according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following example. In each of the drawings described below, the same reference numerals are used for common members. In addition, in the drawings used in this specification, the same reference numerals are used for the same or corresponding components, and repeated description of these components may be omitted. The explanation will be given in the following order. 1. First embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe 2. Second embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe 3. Third embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe 4. Fourth embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe

[0014] 1. First embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe [Configuration of electromagnetic ultrasonic inspection device] Fig. 1 shows the configuration of an electromagnetic ultrasonic inspection device 100 according to this embodiment. The electromagnetic ultrasonic inspection device 100 shown in Fig. 1 includes an electromagnetic ultrasonic probe 10 arranged on the surface of a test object 1, and an ultrasonic flaw detector 20 that controls the electromagnetic ultrasonic probe 10 to record a waveform signal. The electromagnetic ultrasonic inspection device 100 further includes a calculation device 30 connected to the ultrasonic flaw detector 20, and a display device 40, a storage device 50, and an input device 60 each connected to the calculation device 30. For ease of explanation, the curvature of the piping is ignored and the piping is depicted as a flat plate in Fig. 1. In addition, in a direction parallel to the surface of the test object 1, the longitudinal direction of the electromagnetic ultrasonic probe 10 is defined as the x-axis direction, the width direction is defined as the y-axis direction, and the direction perpendicular to the surface of the test object 1 is defined as the z-axis direction.

[0015] The calculation device 30 has, for example, a ROM (Read Only Memory) that stores a program, a CPU (Central Processing Unit) that executes processing according to the program, and a RAM (Random Access Memory) that stores the processing results, and calculates flaw detection images, etc. based on the waveform signals recorded by the ultrasonic flaw detector 20. The display device 40 is, for example, configured with a display, etc., and displays the flaw detection results calculated by the calculation device 30. The storage device 50 is, for example, configured with a non-volatile memory, etc., and stores the flaw detection results calculated by the calculation device 30. The input device 60 is, for example, configured with a touch panel, etc., arranged on the display, and inputs instructions to the calculation device 30 by a user, etc.

[0016] The electromagnetic ultrasonic probe 10 is composed of a magnetic field generating unit 11 and a coil 12 . The ultrasonic flaw detector 20 is composed of a pulser 21, a receiver 22, and a data recording unit 23. The ultrasonic flaw detector 20 outputs a drive signal from the pulser 21 to the coil 12 based on a command from the computing device 30. In the ultrasonic flaw detector 20, an ultrasonic signal from the test object 1 is converted into a voltage waveform signal by the coil 12 and output to the data recording unit 23 via the receiver 22. The data recording unit 23 is composed of, for example, a hard disk or a memory.

[0017] [Configuration of electromagnetic ultrasonic transducer] Next, the configuration of the electromagnetic ultrasonic probe 10 constituting the above-mentioned electromagnetic ultrasonic inspection device will be described. Fig. 2 shows the layout of the electromagnetic ultrasonic probe 10 from above (z-axis direction). Fig. 3 shows the layout of the electromagnetic ultrasonic probe 10 from the side (y-axis direction). 2 and 3, the x-axis direction, the y-axis direction, and the z-axis direction are defined in the same manner as in FIG.

[0018] The electromagnetic ultrasonic probe 10 is disposed on the upper surface of the subject 1, with a magnetic field generating unit 11 and a coil 12 arranged in this order from above the z-axis. The magnetic field generating unit 11 is a magnet unit having an integrated configuration in which magnets 11a, 11b, 11c, and 11d are arranged. The magnetic field generating unit 11 has a structure in which a magnet unit on the rear end side (left side of the figure) in which magnets 11a and 11b are alternately arranged in the x-axis direction and a magnet unit on the front end side (right side of the figure) in which magnets 11c and 11d are alternately arranged are joined together and integrated. The magnetic field generating unit 11 has a structure in which the magnet unit of magnets 11a and 11b and the magnet unit of magnets 11c and 11d are arranged in two rows in the y-axis direction. The coil 12 has a configuration in which a conducting wire is wound in a racetrack shape in the horizontal direction on the surface of the subject 1 .

[0019] The magnetic field generating unit 11 is disposed above the straight portion of the coil 12 which is wound in a racetrack shape. Magnets 11a, 11b, 11c, and 11d constituting magnetic field generating unit 11 are arranged so that the magnetization direction is the z-axis direction. Magnets 11a and 11c are arranged so that they generate a magnetic field vertically upward (positive direction of the z-axis). Magnets 11b and 11d are arranged so that they generate a magnetic field vertically downward (negative direction of the z-axis). For this reason, magnets 11a and 11b, and magnets 11c and 11d are arranged repeatedly in the x-axis direction so that the magnetization directions are alternated. In addition, the magnetic field generating unit 11 has magnets 11a and 11b, and magnets 11c and 11d, which have different magnetization directions, arranged symmetrically about the center position of coil 12 in a direction perpendicular to the straight portion of the conductor wire of coil 12 (the y-axis direction).

[0020] In the magnetic field generating unit 11, the magnets 11a, 11b, 11c, and 11d are repeatedly arranged in the x-axis direction, and the widths (lengths in the x-axis direction) of the magnets 11a and 11b are different from the widths of the magnets 11c and 11d. In the magnetic field generating unit 11, the magnets 11a and 11b arranged in the magnet unit on the rear edge side (left side of the figure) of the magnetic field generating unit 11 are configured with a width L1. In addition, the magnets 11c and 11d arranged in the magnet unit on the front edge side (right side of the figure) of the magnetic field generating unit 11 are configured with a width L2 that is different from the width L1. The width L1 of the magnets 11a and 11b arranged on the rear edge side of the magnetic field generating unit 11 is larger than the width L2 of the magnets 11c and 11d arranged on the rear edge side of the magnetic field generating unit 11. That is, the magnetic field generating unit 11 is configured such that the widths of the magnets 11a, 11b, 11c, and 11d are L1>L2. Therefore, in the electromagnetic ultrasonic probe 10, the magnetic field generating unit 11 has magnets 11a and 11b, each having a width L1, arranged repeatedly on the rear edge side, and magnets 11c and 11d, each having a width L2, arranged repeatedly on the front edge side. In the electromagnetic ultrasonic probe 10, the direction in which the parallel component of the ultrasonic signal to the object surface is positive is defined as the forward direction. Details of the direction of the ultrasonic signal will be described later in FIG. 4. In addition, it is preferable to set the magnet widths L1 and L2 to a value equal to or smaller than the thickness of the object, for example, in consideration of the relationship between the composite wavefront and the thickness of the object, which will be described later. Furthermore, it is preferable to set the magnet widths L1 and L2 to a value equal to or larger than 1 / 2 the ultrasonic wavelength, for example, in consideration of the relationship with the driving frequency of the ultrasonic waves, which will also be described later.

[0021] Both ends of the coil 12 are connected to the pulser 21 and the receiver 22 via, for example, a coaxial cable 13. The conductor extending from the center of the coil 12 to the outside is arranged, for example, with an insulating layer or the like in the z direction from the xy plane on which the coil 12 is arranged, at the portion where it intersects with the wound conductor portion in a plan view, so as to be separated and insulated from the wound conductor portion.

[0022] In the electromagnetic ultrasonic probe 10 shown in Fig. 2 and Fig. 3, the number of repeated arrangements of the magnets 11a, 11b and the number of repeated arrangements of the magnets 11c, 11d in the x-axis direction is 6, and the number of turns of the coil is 5, but the numerical values ​​of the number of repeated arrangements and the number of turns are not limited to these. Also, in the electromagnetic ultrasonic probe 10 shown in Fig. 2 and Fig. 3, the number of repeated arrangements of the magnets 11a, 11b, 11c, 11d in the y-axis direction is 2, but this is not limited to these.

[0023] [How ultrasonic waves are generated] Next, a description will be given of a method for generating ultrasonic waves from the electromagnetic ultrasonic probe 10 in the electromagnetic ultrasonic inspection device 100. Fig. 4 shows the arrangement of the electromagnetic ultrasonic probe 10 from the side direction (y-axis direction) and a schematic diagram of a method for generating ultrasonic waves.

[0024] The electromagnetic ultrasonic probe 10 generates a Lorentz force in the subject 1 by the interaction between the magnetic field generated by each of the magnets 11a, 11b, 11c, and 11d of the magnetic field generating unit 11 and the current generated by the coil 12, and serves as an ultrasonic vibration source. 4, magnetic field B is generated along the z-axis direction by magnets 11a, 11b, 11c, and 11d, and current i flows from left to right in the conductor of coil 12, generating an eddy current j from right to left (negative direction of the x-axis) on the surface of the subject. Then, the interaction between magnetic field B and eddy current j generates a Lorentz force F in the direction perpendicular to the plane of the paper (y-axis direction).

[0025] By periodically changing the direction of the current i flowing through the coil 12, the direction of the eddy current j and the direction of the Lorentz force F can be periodically changed. Therefore, the change in the Lorentz force F becomes the periodic change of the ultrasonic vibration. The generated ultrasonic vibration spreads isotropically and propagates inside the subject. At this time, the ultrasonic vibration generated by the adjacent magnets 11a, 11b, 11c, and 11d with the magnetic flux generation direction reversed becomes a vibration with a half-period shift in periodic fluctuation because the direction of the Lorentz force F is reversed. Therefore, in a specific propagation direction, the ultrasonic vibrations interfere with each other and form a composite wavefront. That is, the ultrasonic waves S1 and S2 propagating in the direction indicated by the solid arrow S in FIG. 4 are in phase, and are reinforced to propagate the ultrasonic waves S1 and S2 with a large amplitude.

[0026] 4 shows an example in which the constructive propagation direction of ultrasonic waves S1 and S2 indicated by an arrow S is at predetermined refraction angles θ1 and θ2 with respect to the vertical downward direction (negative z-axis direction) with respect to the surface of the subject 1. In the region where the magnets 11a and 11b are arranged, an example is shown in which the constructive propagation direction of ultrasonic waves S1 indicated by an arrow S is at a refraction angle θ1. In the region where the magnets 11c and 11d are arranged, an example is shown in which the constructive propagation direction of ultrasonic waves S2 indicated by an arrow S is at a refraction angle θ2.

[0027] The parallel component of the ultrasonic waves S1, S2 to the surface of the subject 1 at the arrow S is defined as the positive x-axis direction, which is the forward direction of the electromagnetic ultrasonic probe 10. The opposite direction to the positive x-axis direction is defined as the negative x-axis direction, which is the backward direction of the electromagnetic ultrasonic probe 10. For this reason, the positive x-axis direction shown in Fig. 4 is the forward direction of the angle beam inspection by the electromagnetic ultrasonic probe 10 (probe oblique forward), and the negative x-axis direction is the backward direction of the angle beam inspection by the electromagnetic ultrasonic probe 10 (probe oblique backward).

[0028] In Fig. 4, the width of the magnets 11a and 11b arranged repeatedly on the left side (behind the probe oblique angle) is L1, and the width of the magnets 11c and 11d arranged repeatedly on the right side (forward of the probe oblique angle) is L2. In this case, the refraction angles θ1 and θ2, which represent the propagation directions in which the ultrasonic waves S1 and S2 constructively interfere with each other, are expressed by formulas (1) and (2).

[0029]

number

[0030]

number

[0031] In formula (1) and formula (2), θ1 is the first refraction angle, θ2 is the second refraction angle, and λ is the wavelength of the propagating ultrasonic wave. The refraction angles θ1 and θ2 are 0 degrees when the ultrasonic wave propagates vertically directly downward within the subject 1, and 90 degrees when the ultrasonic wave propagates along the surface of the subject. That is, the refraction angle θ1 is the angle of the arrow S indicating the ultrasonic wave S1 from the negative direction of the z axis in the region where the magnet units of the magnets 11a and 11b shown in FIG. 4 are arranged. The refraction angle θ2 is the angle of the arrow S indicating the ultrasonic wave S2 from the negative direction of the z axis in the region where the magnet units of the magnets 11c and 11d shown in FIG. 4 are arranged. The wavelength λ is expressed by the formula (3).

[0032]

number

[0033] In formula (3), v is the speed of sound inside the subject, and f is the driving frequency of the ultrasound. In Fig. 4, the wavelength λ1 in the magnet unit of magnets 11a and 11b with width L1, and the wavelength λ2 in the magnet unit of magnets 11c and 11d with width L2 are indicated by dashed lines in a direction perpendicular to the arrow S. The interval between the dashed lines in Fig. 4 indicates λ / 2, and two intervals between the dashed lines correspond to the wavelength λ.

[0034] From the above formula, when the widths L1 and L2 of the repeatedly arranged magnets 11a and 11b and magnets 11c and 11d are different values, the refraction angles θ1 and θ2 at which the ultrasonic waves S1 and S2 reinforce each other will be different values. As a result, ultrasonic waves reinforce each other in multiple propagation directions, such as ultrasonic wave S1 generated in the area of ​​magnets 11a and 11b and ultrasonic wave S2 generated in the area of ​​magnets 11c and 11d. 4, by setting the magnet widths L1 and L2 such that L1>L2, the refraction angle θ2 can be made larger than the refraction angle θ1. That is, the refraction angle θ2 of the ultrasonic waves S2 generated in the area of ​​the magnets 11c and 11d arranged in front of the probe oblique angle becomes larger, so that the oblique angle of the ultrasonic waves S2 toward the front of the probe oblique angle becomes wider. Therefore, the range of the refraction angles θ1 and θ2 within the subject 1 where the ultrasonic waves S1 and S2 with large amplitude reach can be made wider. 1 to 4, the electromagnetic ultrasonic inspection device 100 can reinforce the ultrasonic waves in multiple propagation directions and widen the range of refraction angles that ultrasonic waves with large amplitudes reach while keeping the driving frequency f of the periodic variable signal applied to the coil 12 to oscillate the ultrasonic waves S1 and S2 at a single value. Therefore, the electromagnetic ultrasonic inspection device 100 can widen the inspection range without requiring a control device for controlling the driving frequency.

[0035] [Modification of the electromagnetic ultrasonic probe] Next, a description will be given of an example in which the width of the magnet of the magnetic field generating unit 11 of the electromagnetic ultrasonic probe 10 is changed as a modified example of the electromagnetic ultrasonic inspection device 100. As shown in the above formulas (1) and (2), the refraction angle θ can be changed to an arbitrary value by adjusting the magnet width L. Fig. 5 shows a schematic diagram of the arrangement of the electromagnetic ultrasonic probe 10A with the refraction angle θ changed as viewed from the side (y-axis direction) and the method of generating ultrasonic waves. The electromagnetic ultrasonic probe 10A shown in Fig. 5 has the same configuration as the electromagnetic ultrasonic probe 10 shown in Fig. 4 described above, except for the magnet units of magnets 11e and 11f with width L3 arranged in front of the probe oblique angle of the magnetic field generating unit 11A. Therefore, detailed explanations of the same configurations as the electromagnetic ultrasonic inspection device 100 and the electromagnetic ultrasonic probe 10 shown in Figs. 1 to 4 described above will be omitted.

[0036] The electromagnetic ultrasonic probe 10A shown in FIG. 5 illustrates an example in which the constructive propagation direction of ultrasonic waves S3 in the magnet unit of magnets 11e and 11f arranged in front of the probe oblique angle of the magnetic field generating unit 11A is parallel to the surface of the subject 1, i.e., the refraction angle θ3 is 90°. The width L3 of the magnets 11e and 11f is half the wavelength λ3 of the current signal generated by the coil 12. When the wavelength λ3 is twice the magnet width L3 (λ3=2×L3), the refraction angle θ3 is 90 degrees according to the calculation formulas (1) and (2). That is, the propagation direction of the ultrasonic waves S3 in the magnet units of the magnets 11e and 11f can be parallel to the surface of the test object 1. This shows that the configuration of the electromagnetic ultrasonic probe 10A of this embodiment allows simultaneous inspection of both the inner and outer surfaces of the test object 1. That is, the propagation of the ultrasonic waves S1 in the direction of the refraction angle θ1 allows oblique inspection of the inner surface of the test object 1, and the propagation of the ultrasonic waves S3 in the direction of the refraction angle θ2 allows surface inspection of the outer surface of the test object 1.

[0037] According to the electromagnetic ultrasonic probe 10, 10A having the above configuration, it is possible to realize a device capable of detecting flaws in a wide area by generating ultrasonic waves S1, S2, or S3 in a plurality of propagation directions in the subject 1 without adding a device for controlling the frequency of the applied drive signal. Note that this embodiment shows the basic configuration of the electromagnetic ultrasonic inspection device 100 capable of detecting flaws in a wide area, and for example, the magnetic field generating unit 11 may be configured using three or more types of magnet units each having a different magnet width, and the direction of the refraction angle θ in which the ultrasonic waves propagate may be three or more. In addition, in the magnetic field generating unit 11, the number of magnets arranged in the x-axis direction, the number of magnets arranged in the y-axis direction, and the number of magnets constituting the magnet unit are not limited. For example, the number of magnets repeatedly arranged in the x-axis direction may be less than six or seven or more, and the number of magnets arranged in the y-axis direction may be one or three or more rows. Furthermore, in the electromagnetic ultrasonic inspection device 100 and the electromagnetic ultrasonic probe 10, there are no limitations on the direction of the magnetic field B generated by the magnet, the vibration direction of the generated ultrasonic waves S, the refraction angle θ (0 to 90°), the waveform and frequency of the ultrasonic waves transmitted as ultrasonic inspection conditions, the display method of the inspection results, etc. Furthermore, there are no limitations on the structure and method of each device, and they may be replaced with other structures or methods that provide the same effect.

[0038] 2. Second embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe Next, a second embodiment of the electromagnetic ultrasonic inspection device and the electromagnetic ultrasonic probe will be described. The electromagnetic ultrasonic inspection device of the second embodiment differs from the electromagnetic ultrasonic inspection device of the above-mentioned first embodiment only in the arrangement of magnets in the electromagnetic ultrasonic probe. Therefore, detailed description of the same configuration as the electromagnetic ultrasonic inspection device of the above-mentioned first embodiment will be omitted. Also, only the configuration of the electromagnetic ultrasonic probe will be described below.

[0039] The configuration of the electromagnetic ultrasonic probe in the electromagnetic ultrasonic inspection device of the second embodiment is shown in Fig. 6 and Fig. 7. Fig. 6 is a perspective view of the electromagnetic ultrasonic probe 10B. Fig. 7 shows the arrangement of the electromagnetic ultrasonic probe 10B from the side (y-axis direction). In Fig. 6 and Fig. 7, the x-axis direction, the y-axis direction, and the z-axis direction are defined in the same manner as in Figs. 1-3 described above.

[0040] 6 and 7, the magnetic field generating unit 11B of the electromagnetic ultrasonic probe 10B has a first row of magnet units in which magnets 11a and 11b are alternately arranged in the x-axis direction, and a second row of magnet units in which magnets 11c and 11d are alternately arranged in the x-axis direction, which are arranged in parallel in the y-axis direction. In addition, the magnetic field generating unit 11 has a width L1 of the magnets 11a and 11b arranged in the first row of magnet units, and a width L2 of the magnets 11c and 11d arranged in the second row of magnet units, which are repeated in the x-axis direction, and are configured to have different values. That is, the electromagnetic ultrasonic probe 10B includes a magnetic field generating unit 11B in which magnets 11a, 11b and magnets 11c, 11d having different widths L1, L2 are arranged in a direction perpendicular to the current generated by the coil 12 (y-axis direction).

[0041] In the electromagnetic ultrasonic probe 10B having the above configuration, the propagation direction in which ultrasonic waves constructively interact is different between the region of the first row of magnet units in which the magnets 11a and 11b are arranged and the region of the second row of magnet units in which the magnets 11c and 11d are arranged. As shown in Fig. 4 above, in the magnet unit in which the magnets 11a and 11b are arranged with a width L1, the propagation direction in which ultrasonic waves S1 constructively interact is the refraction angle θ1. In addition, in the magnet unit in which the magnets 11c and 11d are arranged with a width L2, the propagation direction in which ultrasonic waves S2 constructively interact is the refraction angle θ2.

[0042] As in the electromagnetic ultrasonic probe 10B of this embodiment, a row of magnets 11a and 11b with different magnet widths L and a row of magnets 11c and 11d are arranged symmetrically in the y-axis direction with respect to the center position of the coil 12, so that the oscillation center position of ultrasonic propagation can be adjusted. That is, the oscillation center positions of ultrasonic waves S1 and S2 propagated at different refraction angles θ1 and θ2 can be set to the same position in the x-axis direction. Also, for example, the center position of the magnet unit of magnets 11c and 11d with width L2 shown in Figs. 6 and 7 may be moved in the x-axis direction to move the oscillation center position of ultrasonic propagation in the x-axis direction.

[0043] In the configuration of the electromagnetic ultrasonic probe 10 of the first embodiment described above, the magnet unit arranged on the rear edge side with respect to the probe oblique angle and the magnet unit arranged on the front edge side have their respective unit center positions shifted forward and backward with respect to the ultrasonic wave propagation direction. In contrast, the electromagnetic ultrasonic probe 10B of the second embodiment has the effects of the first embodiment described above, and the unit center positions of the magnet widths L1 and L2 can be set to any positions. Therefore, the center positions of the magnet unit with the magnet width L1 and the magnet unit with the magnet width L2 can be set to the same position or different positions in the x-axis direction, improving the design freedom of the electromagnetic ultrasonic inspection device 100.

[0044] 3. Third embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe Next, a third embodiment of the electromagnetic ultrasonic inspection device and the electromagnetic ultrasonic probe will be described. The electromagnetic ultrasonic inspection device of the third embodiment differs from the electromagnetic ultrasonic inspection device of the above-mentioned first embodiment only in the arrangement of magnets in the electromagnetic ultrasonic probe. Therefore, detailed description of the same configuration as the electromagnetic ultrasonic inspection device of the above-mentioned first embodiment will be omitted. Also, only the configuration of the electromagnetic ultrasonic probe will be described below.

[0045] The configuration of the electromagnetic ultrasonic probe in the electromagnetic ultrasonic inspection device of the third embodiment is shown in Fig. 8 and Fig. 9. Fig. 8 is a perspective view of an electromagnetic ultrasonic probe 10C. Fig. 9 shows the arrangement configuration of the electromagnetic ultrasonic probe 10B from the side direction (y-axis direction) and a schematic diagram of ultrasonic waves. In Fig. 8 and Fig. 9, the x-axis direction, the y-axis direction, and the z-axis direction are defined in the same manner as in Figs. 1-3 described above.

[0046] 8 and 9, the magnetic field generating section 11C of the electromagnetic ultrasonic probe 10C has a magnet unit in which magnets 11a1, 11b2, 11a3, 11b4 to 11an-1, and 11bn having different magnet widths are arranged in the x-axis direction. In this configuration, the magnets 11a1, 11b2, 11a3, 11b4 to 11an-1, and 11bn are all formed with different widths L1, L2, L3, L4, . . . Ln-1, Ln. In addition, the widths L1, L2, L3, L4, . . . Ln-1, Ln are configured so that the values ​​are successively smaller from the rear edge side to the front edge side with respect to the probe oblique angle forward. For this reason, the magnets 11a1, 11b2, 11a3, 11b4 to 11an-1, and 11bn are configured so that the relationship is width L1>width L2>width L3>width L4,...>width Ln-1>width Ln. It is preferable that the width difference between adjacent magnets for the widths L1, L2, L3, L4,..., Ln-1, Ln changes continuously. For example, it is preferable that the width difference between adjacent magnets decreases by the same amount or at a predetermined rate from the trailing edge side to the leading edge side with respect to the front of the probe oblique angle.

[0047] In the electromagnetic ultrasonic probe 10C having the above configuration, the refraction angle θ can be continuously changed in the propagation direction in which the ultrasonic waves S4 are reinforced by each other in the magnets 11a1, 11b2, 11a3, 11b4 to 11an-1, and 11bn as shown in Fig. 9. Specifically, by gradually decreasing the value of the magnet width L from the trailing edge side to the leading edge side with respect to the forward oblique angle of the probe as shown in Fig. 9, the refraction angle θ increases toward the leading edge side with respect to the forward oblique angle of the probe as shown in Fig. 9. Regarding the magnet width in this case, if the widest width, i.e., the left end in Figure 9, is L1, the narrowest width, i.e., the right end in Figure 9, is Ln, and the number of magnets arranged is n, then, for example, the width of the mth magnet from the left is set as shown in equation (4).

[0048]

number

[0049] In this setting, the magnet widths are arranged in an equal-difference sequence. Note that this arrangement of magnet widths is a typical example, and is not limited to this setting as long as the magnet widths become smaller in sequence from the trailing edge side to the leading edge side, and may be arranged in an equal-geometric sequence, for example.

[0050] 4. Fourth embodiment of electromagnetic ultrasonic inspection device and electromagnetic ultrasonic probe Next, a fourth embodiment of the electromagnetic ultrasonic inspection device and the electromagnetic ultrasonic probe will be described. The electromagnetic ultrasonic inspection device of the fourth embodiment differs from the electromagnetic ultrasonic inspection device of the first embodiment described above only in the magnets arranged in the electromagnetic ultrasonic probe and the winding method of the coil 12. Therefore, detailed description of the same configuration as the electromagnetic ultrasonic inspection device of the first embodiment described above will be omitted. Also, only the configuration of the electromagnetic ultrasonic probe will be described below.

[0051] The configuration of the electromagnetic ultrasonic probe in the electromagnetic ultrasonic inspection device of the fourth embodiment is shown in Fig. 10, Fig. 11, and Fig. 12. Fig. 10 is a perspective view of an electromagnetic ultrasonic probe 10D. Fig. 11 shows the arrangement of the electromagnetic ultrasonic probe 10D from above (z-axis direction). Fig. 12 shows the arrangement of the electromagnetic ultrasonic probe 10D from the side (y-axis direction). In Fig. 10, Fig. 11, and Fig. 12, the x-axis direction, the y-axis direction, and the z-axis direction are defined in the same manner as in Figs. 1-3 described above.

[0052] As shown in FIG. 10, FIG. 11, and FIG. 12, the magnetic field generating unit 11D of the electromagnetic ultrasonic probe 10D has a magnet unit consisting of magnets 11a and 11b, and a magnet unit consisting of magnets 11c and 11d in the x-axis direction. The magnet unit consisting of magnets 11a and 11b is arranged on the rear end side (left side of the figure) of the magnetic field generating unit 11D, and the magnet unit consisting of magnets 11c and 11d is arranged on the front end side (right side of the figure) of the magnetic field generating unit 11D. The magnets 11a and 11b, the magnets 11c, and the magnets 11d are repeatedly arranged in the x-axis direction so that the magnetization directions in the z-axis direction are alternated. In addition, the magnets 11a, 11b, 11c, and 11d are each formed continuously in the y-axis direction. Therefore, the magnetic field generating unit 11D has a configuration in which the magnet units are arranged in a row in the y-axis direction.

[0053] The coil 12 has a configuration in which a conductor is wound around the magnetic field generating unit 11D in the x-axis direction and the z-axis direction in the xy cross section shown in Fig. 11. The coil 12 has a configuration in which a conductor is wound around the magnetic field generating unit 11D with the y-axis direction as the center position in the xz cross section shown in Fig. 12. The coil 12 is formed of a conductor that is continuous from one end in the y-axis direction to the other end. Therefore, in the electromagnetic ultrasonic probe 10D, the magnets 11a, 11b, 11c, and 11d are arranged in parallel and perpendicular directions to the current generated by the coil 12.

[0054] The electromagnetic ultrasonic probe 10D having the above configuration has the same effects as the electromagnetic ultrasonic inspection device 100 of the first embodiment described above, and can improve the winding density in the y-axis direction compared to a configuration in which a racetrack-shaped coil is provided. Therefore, the ultrasonic amplitude generated by the electromagnetic ultrasonic probe 10D can be increased. Moreover, the electromagnetic ultrasonic probe 10D having the above configuration can eliminate the space of the curved portion of the racetrack-shaped coil, thereby making it possible to reduce the overall size of the electromagnetic ultrasonic probe 10D.

[0055] The configuration of the fourth embodiment can be used in combination with the configuration of the second embodiment or the configuration of the third embodiment. That is, the coil may be wound in the xz plane direction in accordance with the structure of the magnetic field generating unit of the second embodiment and the structure of the magnetic field generating unit of the third embodiment.

[0056] Also, a configuration in which the configuration of the first embodiment and the configuration of the third embodiment are combined, or a configuration in which the configuration of the second embodiment and the configuration of the third embodiment are combined may be used. For example, a configuration in which two rows of magnet units are arranged in the y-axis direction, and the magnet unit described in the third embodiment in which the magnet 11a1 with the width L1 to the magnet 11bn with the width Ln are arranged in the x-axis direction is arranged in the first row. Then, a configuration in which the magnet unit of the first embodiment in which the rear end side in which the magnets 11a and 11b with the width L1 are arranged in the x-axis direction and the front end side in which the magnets 11c and 11d with the width L2 are arranged are integrated may be arranged in the second row. In this way, in the configuration of the second embodiment in which magnet units with different configurations are arranged in the y-axis direction, the magnet units of each row can be configured as described in the first embodiment or the third embodiment. Note that even in such a configuration, the configuration in which the coil of the fourth embodiment is wound in the xz plane direction may be applied.

[0057] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete a part of the configuration of each embodiment, or to add or replace another configuration. [Explanation of symbols]

[0058] 1 Subject, 10, 10A, 10B, 10C, 10D Electromagnetic ultrasonic probe, 100 Electromagnetic ultrasonic inspection device, 11, 11A, 11B, 11C, 11D Magnetic field generator, 11a, 11a1, 11a3, 11an-1, 11b, 11b2, 11b4, 11bn, 11c, 11d, 11e, 11f Magnet, 12 Coil, 13 Coaxial cable, 20 Ultrasonic flaw detector, 21 Pulser, 22 Receiver, 23 Data recording unit, 30 Calculation device, 40 Display device, 50 Storage device, 60 Input device, L1, L2, L3, L4, Ln-1, Ln Width, S1, S2, S3, S4 Ultrasonic wave, θ1, θ2, θ3 Refraction angle, λ1, λ2, λ3 Wavelength

Claims

1. a magnetic field generating unit that generates a magnetic field whose magnetic flux direction alternates on a surface of the subject; a coil for generating a current in a direction perpendicular to the magnetic flux change direction and parallel to the surface of the subject; The magnetic field generating unit is A plurality of magnets having different widths are arranged in a direction parallel to the current generated by the coil, The magnet is arranged such that the width of the magnet arranged on the rear edge side is larger than the width of the magnet arranged on the front edge side along the direction in which the parallel component of the irradiated ultrasonic signal to the surface of the subject is positive in the oblique angle inspection direction to be inspected. Electromagnetic ultrasound probe.

2. a magnetic field generating unit that generates a magnetic field whose magnetic flux direction alternates on a surface of the subject; a coil for generating a current in a direction perpendicular to the magnetic flux change direction and parallel to the surface of the subject; The magnetic field generating unit is A plurality of magnets having different widths are arranged in a direction perpendicular to the current generated by the coil. Electromagnetic ultrasound probe.

3. The magnets having the same width are arranged in a direction parallel to the current. The electromagnetic ultrasonic probe according to claim 2 .

4. The width of the magnet is half the wavelength of the current signal generated in the coil.

3. The electromagnetic ultrasonic probe according to claim 1 or 2.

5. The width of the magnet in the direction parallel to the current is different from one another.

2. The electromagnetic ultrasonic probe according to claim 1.

6. The electromagnetic ultrasonic probe according to claim 1 or 2, and an ultrasonic flaw detector that controls the electromagnetic ultrasonic probe to record a waveform signal. Electromagnetic ultrasonic inspection equipment.

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