Electromagnetic ultrasonic probe, electromagnetic ultrasonic probe system, and ultrasonic flaw detector

Abstract

To provide an electromagnetic ultrasonic probe capable of forming an appropriate static magnetic field by a subject, a system of the electromagnetic ultrasonic probe equipped with the electromagnetic ultrasonic probe for transmission and reception, and an ultrasonic flaw detector equipped with the system of the electromagnetic ultrasonic probe.SOLUTION: The electromagnetic ultrasound probes TR and RE according to the present invention include the ring-shaped first magnets 1Ta and 1Ra magnetized in the axial direction and the coils 2Ta and 2Ra around which a conductive member elongated in one direction is wound, and in a case in which the examination object Ob is disposed inside the first magnets 1Ta and 1Ra and inside the coils 2Ta and 2Ra, the coils 2Ta and are disposed at positions closer to the examination object Ob than the first magnets and in the radial direction. 2Ra 1Ta 1Ra.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic ultrasonic probe that utilizes a magnetic field, an electromagnetic ultrasonic probe system that includes the electromagnetic ultrasonic probe for transmission and reception, and an ultrasonic flaw detection device that includes the electromagnetic ultrasonic probe system. [Background technology]

[0002] Ultrasonic flaw detection, which uses ultrasonic waves to detect defects in a test object, such as cracks, cavities, inclusions, recesses, thinning, etc., is used in a variety of cases because it allows non-destructive testing of the test object. One such method is an ultrasonic flaw detection method using guided waves, which is disclosed in, for example, Patent Document 1.

[0003] The inspection method disclosed in Patent Document 1 is a method of generating a guided wave that propagates through an inspection object to be measured in its longitudinal direction, detecting a reflected wave of the guided wave, and inspecting the inspection object based on the reflected wave. This inspection method uses an inspection device that includes: a coil to which an AC current is applied and wound around a tubular or rod-shaped inspection object; a substantially U-shaped first magnet with a north pole on one side of the coil and a south pole on the other side of the coil, arranged to sandwich the coil and with the north pole and south pole pressed against the outer circumferential surface of the inspection object; and a detection unit that detects the voltage between both ends of the coil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-149792 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the inspection device disclosed in Patent Document 1, when the object to be inspected is a non-magnetic body, the magnetic field does not follow the longitudinal direction of the object to be inspected, and when the approximately U-shaped first magnet is relatively long in the longitudinal direction, the magnetic field generated by the first magnet may be weakened in the area surrounded by the coil, and the excited ultrasonic waves may become weak, so there is room for improvement.

[0006] The present invention has been made in view of the above circumstances, and its object is to provide an electromagnetic ultrasonic probe that can form an appropriate static magnetic field in a subject, an electromagnetic ultrasonic probe system that includes the electromagnetic ultrasonic probe for transmission and reception, and an ultrasonic flaw detection device that includes the electromagnetic ultrasonic probe system. [Means for solving the problem]

[0007] After extensive investigation, the present inventors have found that the above object can be achieved by the present invention described below. That is, an electromagnetic ultrasonic probe according to one aspect of the present invention comprises a ring-shaped first magnet that is magnetized in the axial direction, and a coil in which a long conductor member is wound in one direction, and when a subject is placed inside the first magnet and inside the coil, the coil is placed at a position closer to the subject in the radial direction than the first magnet. Preferably, in the above electromagnetic ultrasonic probe, there is one first magnet and one coil, which is placed inside the first magnet in the axial direction. Preferably, in the above electromagnetic ultrasonic probe, the coil has one turn or multiple turns.

[0008] Such an electromagnetic ultrasonic probe includes a ring-shaped first magnet, which can cover the entire circumference of the subject, and a coil is positioned radially closer to the subject than the first magnet, which is magnetized in the axial direction. Therefore, magnetic field lines extending from a first magnetic pole formed on one end face of the first magnet to a second magnetic pole formed on the other end face of the first magnet generate a static magnetic field that is more appropriate for the subject, such that eddy currents generated in the subject by the coil are axial magnetic field lines or radial magnetic field lines depending on the position of the coil relative to the first magnet.

[0009] In another aspect, in the electromagnetic ultrasonic probe described above, the first magnets are a plurality of first magnets arranged side by side in the axial direction so that two adjacent first magnets face each other with the same poles, and the coil is a single coil arranged inside one of the plurality of first magnets in the axial direction. Preferably, in the electromagnetic ultrasonic probe described above, the two adjacent first magnets are in close contact with each other or spaced apart.

[0010] Such an electromagnetic ultrasonic probe is equipped with multiple first magnets, so that it can form a stronger static magnetic field (a static magnetic field with a high magnetic flux density), and by arranging a coil inside the first magnets, it can generate a static magnetic field that is more suitable for the subject, so that the eddy currents generated in the subject by the coil become axial magnetic field lines.

[0011] In another aspect, in the electromagnetic ultrasonic probe described above, the coil is disposed inside a first magnet that is positioned at the center in the axial direction.

[0012] Such an electromagnetic ultrasonic probe can form a stronger axial magnetic field inside the first magnet located at the center in the axial direction and in the subject surrounded by the first magnet.

[0013] In another aspect, in the above-mentioned electromagnetic ultrasonic probe, the first magnets are a plurality of first magnets arranged side by side in the axial direction so that two adjacent first magnets face each other with the same poles, and the coil is a single coil arranged in the adjacent portion of two adjacent first magnets in the plurality of first magnets in the axial direction.

[0014] Such an electromagnetic ultrasonic probe has a coil disposed adjacent to the subject, and therefore can generate a static magnetic field more appropriate for the subject, which generates radial magnetic field lines in response to eddy currents generated in the subject by the coil.

[0015] In another aspect, in the electromagnetic ultrasonic probe described above, the first magnets are a plurality of first magnets arranged side by side in the axial direction so that two adjacent first magnets face each other with the same poles, and the coils are a plurality of coils, each of which is arranged inside a plurality of adjacent portions of two adjacent first magnets in the axial direction. Preferably, in the electromagnetic ultrasonic probe described above, the number of coils is the same as the number of first magnets. Preferably, in the electromagnetic ultrasonic probe described above, the number of coils is smaller than the number of first magnets.

[0016] Such an electromagnetic ultrasonic probe includes a plurality of first magnets and a plurality of coils, and therefore can generate stronger ultrasonic waves.

[0017] In another aspect, in the electromagnetic ultrasonic probe described above, the first magnet is one or a plurality of coils arranged side by side in the axial direction so that two adjacent first magnets face each other with the same poles, and the coil is arranged inside the one first magnet or inside any one of the plurality of first magnets, and is a plurality of coils arranged side by side in the axial direction so that the direction of current flow alternates. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for transmission is set according to the wavelength of ultrasonic waves generated in the subject by the electromagnetic ultrasonic probe. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for transmission is half the wavelength of the ultrasonic waves generated in the subject by the electromagnetic ultrasonic probe. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for reception is set according to the wavelength of ultrasonic waves to be received by the electromagnetic ultrasonic probe. Preferably, in the electromagnetic ultrasonic probe described above, for reception, the interval between the plurality of coils is half the wavelength of the ultrasonic waves to be received by the electromagnetic ultrasonic probe.

[0018] Such an electromagnetic ultrasonic probe has a plurality of coils arranged inside the first magnet, and therefore can transmit and receive ultrasonic waves in a specific (desired) mode.

[0019] In another aspect, in the electromagnetic ultrasonic probe described above, the first magnets are a plurality of first magnets arranged side by side in the axial direction so that two adjacent first magnets face each other with the same poles, and the coils are a plurality of coils, each of which is arranged inside a plurality of the first magnets in the axial direction. Preferably, in the electromagnetic ultrasonic probe described above, two adjacent first magnets are in close contact with each other or spaced apart. Preferably, in the electromagnetic ultrasonic probe described above, the number of the coils is the same as the number of the first magnets. Preferably, in the electromagnetic ultrasonic probe described above, the number of the coils is smaller than the number of the first magnets.

[0020] Such an electromagnetic ultrasonic probe includes a plurality of first magnets and a plurality of coils, and therefore can generate stronger ultrasonic waves.

[0021] In another aspect, in the electromagnetic ultrasonic probe described above, the first magnets are a plurality of first magnets arranged side by side in the axial direction so that two adjacent first magnets face each other with the same poles, and the coils are a plurality of coils arranged at each of a plurality of adjacent portions of two adjacent first magnets in the axial direction. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for transmission is set according to the wavelength of ultrasonic waves to be generated in the subject by the electromagnetic ultrasonic probe. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for transmission is set to a half wavelength of ultrasonic waves to be generated in the subject by the electromagnetic ultrasonic probe. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for reception is set according to the wavelength of ultrasonic waves to be received by the electromagnetic ultrasonic probe. Preferably, in the electromagnetic ultrasonic probe described above, the spacing between the plurality of coils for reception is set to a half wavelength of ultrasonic waves to be received by the electromagnetic ultrasonic probe.

[0022] Such an electromagnetic ultrasonic probe has a plurality of coils arranged inside each of a plurality of first magnets, and therefore can transmit and receive ultrasonic waves in a specific (desired) mode at a specific (desired) speed.

[0023] In another aspect, the above-mentioned electromagnetic ultrasonic probe further comprises a ring-shaped second magnet magnetized in the radial direction, the second magnet being juxtaposed in the axial direction to the first magnet on the side of the one end face so that the magnetic pole of the one end face of the first magnet in the axial direction and the magnetic pole of the inner peripheral surface of the second magnet are of the same polarity, and the coil is one coil positioned inside the first magnet, or a plurality of coils positioned inside the first magnet and juxtaposed in the axial direction so that the directions of current flow alternate.

[0024] Such an electromagnetic ultrasonic probe further includes a second magnet axially juxtaposed to the first magnet, and therefore can form a stronger static magnetic field (static magnetic field with high magnetic flux density) and generate stronger ultrasonic waves.

[0025] In another aspect, the above-mentioned electromagnetic ultrasonic probe further includes second and third magnets in the shape of rings magnetized in the radial direction, the second magnet being juxtaposed in the axial direction on one end face side of the first magnet so that the magnetic pole on one end face of the first magnet in the axial direction and the magnetic pole on the inner peripheral surface of the second magnet are of the same polarity, the third magnet being juxtaposed in the axial direction on the other end face side of the first magnet so that the magnetic pole on the other end face of the first magnet in the axial direction and the magnetic pole on the inner peripheral surface of the third magnet are of the same polarity, and the coil is one coil positioned inside the first magnet, or multiple coils positioned inside the first magnet and juxtaposed in the axial direction so that the direction of current flow alternates.

[0026] Such an electromagnetic ultrasonic probe further includes second and third magnets that are axially juxtaposed to the first magnet, so that a stronger static magnetic field (a static magnetic field with a high magnetic flux density) can be formed, and stronger ultrasonic waves can be generated.

[0027] In another aspect, the electromagnetic ultrasonic probe described above further comprises a ring-shaped fourth magnet magnetized in the radial direction, wherein the first magnets are a plurality of first magnets arranged side by side in the axial direction so that two adjacent first magnets face each other with the same pole, and the fourth magnets are arranged side by side in the radial direction on the outer periphery of the two first magnets facing each other with the same pole so that at each point where the same pole faces each other, the pole of the same pole and the magnetic pole on the inner surface of the fourth magnet are the same pole, and the coil is one coil arranged inside the first magnet, or a plurality of coils arranged inside the first magnet and arranged side by side in the axial direction so that the direction of current flow alternates.

[0028] Such an electromagnetic ultrasonic probe further includes a fourth magnet arranged radially adjacent to the outer periphery of the first magnet at each point where the magnets face each other with the same polarity, thereby forming a stronger static magnetic field (a static magnetic field with a high magnetic flux density) and generating stronger ultrasonic waves.

[0029] In another aspect, in the electromagnetic ultrasonic probe described above, the second magnet is formed of a plurality of segment magnets that are sequentially arranged in the circumferential direction to form a ring shape.

[0030] In such an electromagnetic ultrasonic probe, the second magnet is formed by a plurality of segment magnets, so that the second magnet can be easily produced.

[0031] In another aspect, in the electromagnetic ultrasonic probe described above, the second and third magnets are each formed of a plurality of segment magnets that are sequentially arranged in the circumferential direction to form a ring shape.

[0032] In such an electromagnetic ultrasonic probe, the second and third magnets are each formed from a plurality of segment magnets, so that the second and third magnets can be easily produced.

[0033] In another aspect, in the electromagnetic ultrasonic probe described above, the fourth magnet is formed of a plurality of segment magnets that are sequentially arranged in the circumferential direction to form a ring shape.

[0034] In such an electromagnetic ultrasonic probe, the fourth magnet is formed by a plurality of segment magnets, so that the fourth magnet can be easily produced.

[0035] An electromagnetic ultrasonic probe system according to another aspect of the present invention includes any one of the above-mentioned electromagnetic ultrasonic probes used for transmission, and any one of the above-mentioned electromagnetic ultrasonic probes used for reception.

[0036] This makes it possible to provide an electromagnetic ultrasonic probe system including the electromagnetic ultrasonic probe. The electromagnetic ultrasonic probe system includes the electromagnetic ultrasonic probe, and therefore can form a more appropriate static magnetic field in the subject.

[0037] An ultrasonic flaw detection device according to another aspect of the present invention includes the above-described electromagnetic ultrasonic probe system.

[0038] This makes it possible to provide an ultrasonic flaw detector equipped with the electromagnetic ultrasonic probe system. Since the ultrasonic flaw detector is equipped with the electromagnetic ultrasonic probe system, it can form a static magnetic field that is more appropriate for the test object. In particular, when the ultrasonic flaw detector is equipped with an electromagnetic ultrasonic probe system that can transmit and receive ultrasonic waves in a specific mode at a specific velocity, it is only necessary to analyze the ultrasonic waves in this specific mode at a specific velocity, thereby simplifying the analysis. [Effects of the Invention]

[0039] The electromagnetic ultrasonic probe according to the present invention can form a more appropriate static magnetic field in a test object. According to the present invention, an electromagnetic ultrasonic probe system including such an electromagnetic ultrasonic probe can be provided. According to the present invention, an ultrasonic flaw detection device including the electromagnetic ultrasonic probe system can be provided. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a diagram for explaining a system of an electromagnetic ultrasonic probe in a first embodiment. [Figure 2]FIG. 2 is a diagram showing an output signal of a receiving electromagnetic ultrasonic probe as an example in the electromagnetic ultrasonic probe system in the first embodiment. [Figure 3] FIG. 10 is a diagram for explaining an electromagnetic ultrasonic probe system according to a second embodiment. [Figure 4] FIG. 10 is a diagram showing an output signal of an electromagnetic ultrasonic probe for reception, as an example, in the electromagnetic ultrasonic probe system according to the second embodiment. [Figure 5] FIG. 10 is a perspective view for explaining an electromagnetic ultrasonic probe system according to a third embodiment. [Figure 6] FIG. 10 is a diagram for explaining an electromagnetic ultrasonic probe system according to a fourth embodiment. [Figure 7] FIG. 10 is a diagram showing an output signal of an electromagnetic ultrasonic probe for reception, as an example, in an electromagnetic ultrasonic probe system according to the fourth embodiment. [Figure 8] FIG. 10 is a perspective view for explaining an electromagnetic ultrasonic probe system according to a fifth embodiment. [Figure 9] FIG. 13 is a perspective view for explaining a system of an electromagnetic ultrasonic probe according to a sixth embodiment. [Figure 10] 13 is a diagram for explaining the system of an electromagnetic ultrasonic probe and the analysis results of a magnetic field in the seventh embodiment. FIG. [Figure 11] 10A and 10B are diagrams for explaining analysis results of magnets and magnetic fields in a comparative example. [Figure 12] 10A and 10B are diagrams for explaining an electromagnetic ultrasonic probe and a magnetic field analysis result of one example in the electromagnetic ultrasonic probe system of the second embodiment. [Figure 13] 13 is a diagram for explaining an electromagnetic ultrasonic probe of a comparative example in the electromagnetic ultrasonic probe system of the seventh embodiment and the analysis results of the magnetic field. FIG. [Figure 14] 13 is a diagram for explaining the system of an electromagnetic ultrasonic probe and the analysis results of a magnetic field in the eighth embodiment. FIG. [Figure 15] 13A and 13B are diagrams for explaining the system of an electromagnetic ultrasonic probe and the analysis results of a magnetic field in the ninth embodiment. [Figure 16] 13A and 13B are diagrams for explaining the system of an electromagnetic ultrasonic probe and the analysis results of a magnetic field in the tenth embodiment. [Figure 17] FIG. 13 is a perspective view for explaining a modified form of the second magnet in the electromagnetic ultrasonic probe of the seventh embodiment. [Figure 18] 13A to 13C are perspective views for explaining modified forms of the second to fourth magnets in the electromagnetic ultrasonic probes of the eighth to tenth embodiments. [Figure 19] FIG. 20 is a block diagram showing the configuration of an ultrasonic flaw detector according to an eleventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. In addition, components with the same reference numerals in each drawing indicate the same components, and their description will be omitted as appropriate. In this specification, when referring to a general term, a reference numeral without a subscript is used, and when referring to an individual component, a reference numeral with a subscript is used.

[0042] (First embodiment) Fig. 1 is a diagram for explaining an electromagnetic ultrasonic probe system in the first embodiment, in which Fig. 1A is a perspective view and Fig. 1B is a longitudinal cross-sectional view (vertical cross-sectional view).

[0043] The electromagnetic ultrasonic probe system Sa in the first embodiment includes, for example, an electromagnetic ultrasonic probe TRa used for transmission and an electromagnetic ultrasonic probe REa used for reception, as shown in FIG.

[0044] Since these electromagnetic ultrasonic probes TRa and REa have the same structure, the transmitting electromagnetic ultrasonic probe TRa will be mainly described below, and the reference numeral of the configuration of the receiving electromagnetic ultrasonic probe REa will be written in parentheses after the reference numeral of the configuration of the transmitting electromagnetic ultrasonic probe TRa corresponding to the configuration of the receiving electromagnetic ultrasonic probe REa, thereby substituting the reference numeral of the receiving electromagnetic ultrasonic probe REa for the reference numeral of the transmitting electromagnetic ultrasonic probe TRa, and the description of the receiving electromagnetic ultrasonic probe REa will be omitted. The same applies to second to fourth and sixth embodiments described later.

[0045] The electromagnetic ultrasonic probe TRa (REa) includes a ring-shaped first magnet 1Ta (1Ra) magnetized in the axial direction and a coil 2Ta (2Ra) formed by winding a long conductive material in one direction. The ring shape may have any shape, such as a polygon, regular polygon, ellipse, or circle, in a longitudinal cross section perpendicular to the central axis. In the following embodiment, a cylindrical shape with a circular longitudinal cross section will be described as an example.

[0046] In this embodiment, the first magnet 1Ta (1Ra) is a permanent magnet from the viewpoint of power saving, but it may also be an electromagnet. The first magnet 1Ta (1Ra) is magnetized in the axial direction, so that a first magnetic pole (e.g., a north pole) is formed on one end face, and a second magnetic pole (e.g., a south pole) different from the first magnetic pole is formed on the other end face. The coil 2Ta (2Ra) may be one turn, where a long conductor member is wound once in one direction, or may be multiple turns, where a long conductor member is wound multiple times.

[0047] When the subject Ob is placed inside the first magnet 1Ta (1Ra) and inside the coil 2Ta (2Ra), the coil 2Ta (2Ra) is positioned radially closer to the subject Ob than the first magnet 1Ta (1Ra), as shown in FIG. 1B. More specifically, there is one coil 2Ta (2Ra), and it is positioned axially inside the first magnet 1Ta (1Ra) (inside the first magnet 1Ta (1Ra)) and at its central position. More specifically, the subject Ob is preferably shaped like a column having a cross section similar to that of the first magnet 1Ta (1Ra), and in this embodiment, it is shaped like a cylinder or a column. The first magnet 1Ta (1Ra), coil 2Ta (2Ra), and subject Ob are coaxially arranged radially from the inside to the outside in the order of subject Ob, coil 2Ta (2Ra), and first magnet 1Ta (1Ra). Therefore, the inner diameter of the first magnet 1Ta (1Ra) is larger (longer) than the outer diameter of the coil 2Ta (2Ra). The object Ob must be a member having a diameter (outer diameter) smaller (shorter) than the inner diameter of the coil 2Ta (2Ra). The object Ob may be a magnetic material, such as a metal (including an alloy), as long as it is an electrically conductive material, or may be a non-magnetic material.

[0048] When ultrasonic testing is performed, as shown in FIG. 1A, an object Ob is inserted into a transmitting electromagnetic ultrasonic probe TRa and a receiving electromagnetic ultrasonic probe REa, and the transmitting electromagnetic ultrasonic probe TRa and the receiving electromagnetic ultrasonic probe REa are arranged at a predetermined distance in the axial direction.

[0049] In the transmitting electromagnetic ultrasonic probe TRa, the first magnet 1Ta generates a static magnetic field with magnetic field lines along the axial direction in the object Ob surrounded by the first magnet 1Ta. When an AC current is applied to the coil 2Ta, eddy currents are generated in the object Ob. The axial magnetic field lines in the static magnetic field and the eddy currents generate a radial Lorentz force, which excites ultrasonic waves as guided waves in the object Ob. If the object Ob is a magnetic body, a magnetostrictive force is generated, which excites ultrasonic waves as guided waves in the object Ob. The excited ultrasonic waves propagate through the object Ob. In the receiving electromagnetic ultrasonic probe REa, an AC current is generated in the object Ob due to the interaction between the vibration of the object Ob caused by the ultrasonic waves and the static magnetic field with magnetic field lines along the axial direction generated in the object Ob by the first magnet 1Ra. The fluctuating magnetic field (AC magnetic field) caused by this AC current generates a current in the coil 2Ra, and the fluctuating magnetic field is detected by the coil 2Ra.

[0050] A specific example (first specific example) of the first embodiment will be described. In this first specific example, the object Ob is a stainless steel wire or round bar having a diameter of 12 [mm] and a length of 1500 [mm]. The first magnets 1Ta and 1Ra are permanent magnets having an outer diameter of 27.8 [mm], an inner diameter of 15 [mm], and an axial length (width) of 15 [mm]. The distance between the transmitting electromagnetic ultrasonic probe TRa and the receiving electromagnetic ultrasonic probe REa is 300 [mm] at each axial center position of each of the first magnets 1Ta and 1Ra (i.e., the position of each coil 2Ta and 2Ra). FIG. 2 shows an example of a received signal output from the receiving electromagnetic ultrasonic probe REa when an AC current that is a 5-cycle burst wave at 1 [MHz] is applied to the transmitting electromagnetic ultrasonic probe TRa in this first specific example. FIG. 2 is a diagram showing an output signal of the receiving electromagnetic ultrasonic probe as an example in the electromagnetic ultrasonic probe system in the first embodiment. The horizontal axis of Figure 2 represents time in milliseconds [ms], and the vertical axis represents signal magnitude (amplitude) in millivolts [mV]. As shown in Figure 2, even if the specimen Ob is a non-magnetic stainless steel wire or rod with a relatively small diameter, it is clear that guided wave ultrasonic waves are excited by the transmitting electromagnetic ultrasonic probe TRa, and the ultrasonic waves propagating through the stainless steel wire or rod are received by the receiving electromagnetic ultrasonic probe REa.

[0051] As described above, the electromagnetic ultrasonic probe system Sa and the electromagnetic ultrasonic probes TRa, REa in the first embodiment include ring-shaped first magnets 1Ta, 1Ra, so that the outer periphery of the object Ob can be covered by the first magnets 1Ta, 1Ra all around, and the coils 2Ta, 2Ra are arranged at positions radially closer to the object Ob than the first magnets 1Ta, 1Ra which are magnetized in the axial direction. Therefore, magnetic field lines extending from a first magnetic pole formed on one end face of the first magnets 1Ta, 1Ra to a second magnetic pole formed on the other end face of the first magnets 1Ta, 1Ra can generate a static magnetic field more appropriate for the object Ob, such that the magnetic field lines directed in the axial direction correspond to the positions of the coils 2Ta, 2Ra relative to the first magnets 1Ta, 1Ra, in response to eddy currents generated in the object Ob by the coils 2Ta, 2Ra.

[0052] Next, another embodiment will be described. (Second embodiment) The electromagnetic ultrasonic probes TRa and REa in the first embodiment are configured with one first magnet 1Ta and 1Ra, while the electromagnetic ultrasonic probes TRb and REb in the second embodiment are configured with a plurality of first magnets 1Tb and 1Rb.

[0053] Fig. 3 is a diagram for explaining the system of the electromagnetic ultrasonic probe in the second embodiment, Fig. 3A is a perspective view, and Fig. 3B is a longitudinal cross-sectional view (vertical cross-sectional view).

[0054] The electromagnetic ultrasonic probe system Sb in the second embodiment includes, for example, an electromagnetic ultrasonic probe TRb used for transmission and an electromagnetic ultrasonic probe REb used for reception, as shown in FIG.

[0055] The electromagnetic ultrasonic probe TRb (REb) includes a plurality of ring-shaped first magnets 1Tb (1Rb) magnetized in the axial direction, and one coil 2Tb (2Rb) made of a long conductive member wound in one direction.

[0056] The multiple first magnets 1Tb (1Rb) are arranged side by side in the axial direction so that two adjacent first magnets 1Tb (1Rb) face each other with the same poles. Each of the first magnets 1Tb (1Rb) itself is similar to the first magnet 1Ta (1Ra) in the electromagnetic acoustic probe TRa (REa) of the first embodiment. In the example shown in Fig. 3, the multiple first magnets 1Tb (1Rb) are made up of two 1A and 1B magnets 1Tb-1, 1Tb-2 (1Rb-1, 1Rb-2), which are arranged side by side with their north poles facing each other.

[0057] The coil 2Tb (2Rb) is arranged inside one of the plurality of first magnets 1Tb (1Rb) in the axial direction. In the example shown in FIG. 3, the coil 2Tb (2Rb) is arranged inside the firstB magnet 1Tb-2 (1Rb-2). Note that the coil 2Tb (2Rb) may also be arranged inside the firstA magnet 1Tb-1 (1Rb-1). The coil 2Tb (2Rb) itself is similar to the coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0058] When ultrasonic testing is performed, as shown in FIG. 3A, an object Ob is inserted into a transmitting electromagnetic ultrasonic probe TRb and a receiving electromagnetic ultrasonic probe REb, and the transmitting electromagnetic ultrasonic probe TRb and the receiving electromagnetic ultrasonic probe REb are arranged at a predetermined interval in the axial direction, and function in the same manner as in the first embodiment.

[0059] A specific example (second specific example) of the second embodiment will be described. The subject Ob, the first-A and first-B magnets 1Tb-1, 1Rb-1; 1Tb-2, 1Rb-2, and the coils 2Tb and 2Rb in this second specific example are identical in terms of dimensions and other conditions to the subject Ob, the first magnets 1Ta and 1Ra, and the coils 2Ta and 2Ra in the first specific example. The distance between the transmitting electromagnetic ultrasonic probe TRb and the receiving electromagnetic ultrasonic probe REb is 300 [mm] at the positions of the coils 2Tb and 2Rb. FIG. 4 shows an example of a received signal output from the receiving electromagnetic ultrasonic probe REb when an AC current, which is a 5-cycle burst wave at 1 [MHz], is applied to the transmitting electromagnetic ultrasonic probe TRb in this second specific example. FIG. 4 is a diagram showing an output signal of the receiving electromagnetic ultrasonic probe as an example in the electromagnetic ultrasonic probe system in the second embodiment. The horizontal axis of Figure 4 represents time in milliseconds [ms], and the vertical axis represents signal magnitude (amplitude) in millivolts [mV]. As shown in Figure 4, even if the specimen Ob is a non-magnetic stainless steel wire rod with a relatively small diameter, guided wave ultrasonic waves are excited by the transmitting electromagnetic ultrasonic probe TRb, and the ultrasonic waves propagating through the stainless steel wire or rod are received by the receiving electromagnetic ultrasonic probe REb. As can be seen from a comparison of the received signal of the first specific example shown in Figure 2 with the received signal of the second specific example shown in Figure 4, the maximum amplitude of the received signal of the second specific example is greater than that of the first specific example.

[0060] As described above, the electromagnetic ultrasonic probe system Sb and the electromagnetic ultrasonic probes TRb, REb in the second embodiment are provided with a plurality of first magnets 1Tb, 1Rb, and therefore can form a stronger static magnetic field (a static magnetic field with a high magnetic flux density), and since the coils 2Tb, 2Rb are arranged inside the first magnets 1Tb, 1Rb, a static magnetic field that is more appropriate for the object Ob can be generated, such that axial magnetic field lines are generated in response to eddy currents generated in the object Ob by the coils 2Tb, 2Rb.

[0061] Next, another embodiment will be described. (Third embodiment) The electromagnetic ultrasonic probes TRb and REb in the second embodiment are configured with one coil 2Tb and 2Rb inside one of the multiple first magnets 1Tb and 1Rb, while the electromagnetic ultrasonic probes TRc and REc in the third embodiment are configured with one coil 2Tc and 2Rc inside the first magnet 1Tc and 1Rc that is located at the center in the axial direction among the multiple first magnets 1Tc and 1Rc.

[0062] FIG. 5 is a perspective view for explaining an electromagnetic ultrasonic probe system according to the third embodiment.

[0063] The electromagnetic ultrasonic probe system Sc in the third embodiment includes, for example, an electromagnetic ultrasonic probe TRc used for transmission and an electromagnetic ultrasonic probe REc used for reception, as shown in FIG.

[0064] The electromagnetic ultrasonic probe TRc (REc) includes a plurality of ring-shaped first magnets 1Tc (1Rc) magnetized in the axial direction, and one coil 2Tc (2Rc) made of a long conductive member wound in one direction.

[0065] The multiple first magnets 1Tc (1Rc) are arranged in parallel in the axial direction so that two adjacent first magnets 1Tc (1Rc) face each other with the same poles. Each of the first magnets 1Tc (1Rc) itself is similar to the first magnet 1Ta (1Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment. In the example shown in Figure 5, the multiple first magnets 1Tc (1Rc) consist of three 1A to 1C magnets 1Tc-1, 1Tc-2, 1Tc-3 (1Rc-1, 1Rc-2, 1Rc-3), and the 1A and 1B magnets 1Tc-1, 1Tc-2 (1Rc-1, 1Rc-2) are arranged side by side with their north poles facing each other, and the 1B and 1C first magnets 1Tc-2, 1Tc-3 (1Rc-2, 1Rc-3) are arranged side by side with their south poles facing each other.

[0066] The coil 2Tc (2Rc) is arranged inside the first magnet 1Tc (1Rc) that is located at the center in the axial direction among the plurality of first magnets 1Tc (1Rc). In the example shown in Fig. 5, the coil 2Tc (2Rc) is arranged inside the firstB magnet 1Tc-2 (1Rc-2) that is located at the center in the axial direction. The coil 2Tc (2Rc) itself is similar to the coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0067] When ultrasonic testing is performed, as shown in FIG. 5, an object Ob is inserted into the transmitting electromagnetic ultrasonic probe TRc and the receiving electromagnetic ultrasonic probe REc, and the transmitting electromagnetic ultrasonic probe TRc and the receiving electromagnetic ultrasonic probe REc are arranged at the positions of the coils 2Tc and 2Rc with a predetermined gap in the axial direction, and function in the same manner as in the first embodiment.

[0068] As described above, the electromagnetic ultrasonic probe system Sc and the electromagnetic ultrasonic probes TRc, REc in the third embodiment are equipped with a plurality of first magnets 1Tc, 1Rc, and therefore can form a stronger static magnetic field (a static magnetic field with a high magnetic flux density), and can form a stronger axial magnetic field in the subject Ob surrounded by the first magnets 1Tc, 1Rc inside the first magnets 1Tc, 1Rc located in the center in the axial direction.

[0069] In the second embodiment described above, the number of first magnets 1Tb (1Rb) was two, but this is not limited to this and may be three or more. Similarly, in the third embodiment described above, the number of first magnets 1Tc (1Rc) was three, but this is not limited to this and may be four or more. The first magnets 1T (1R) are arranged side by side in the axial direction so that two adjacent first magnets 1T (1R) face each other with the same poles, and a coil 2T (2R) is arranged on one first magnet 1T (1R) located in a central position or on one of two first magnets 1T (1R) located adjacent to the central position.

[0070] Furthermore, in the second and third embodiments described above, two adjacent first magnets 1Tb, 1Rb; 1Tc, 1Rc may be spaced apart or in close contact with each other. When two adjacent first magnets 1Tb, 1Rb; 1Tc, 1Rc are spaced apart or in close contact with each other, these first magnets 1Tb, 1Rb; 1Tc, 1Rc are arranged side by side with the same poles facing each other, so a jig for spaced apart or in close contact with these first magnets 1Tb, 1Rb; 1Tc, 1Rc is further provided. The jig is, for example, a member that extends in the axial direction, one end of which engages (couples) with one end of the first magnets 1Tb, 1Rb; 1Tc, 1Rc, and the other end of which engages (couples) with the other end of the first magnets 1Tb, 1Rb; 1Tc, 1Rc. When two adjacent first magnets 1Tb, 1Rb; 1Tc, 1Rc are to be brought into close contact with each other, they may be bonded with an adhesive instead of using the jig.

[0071] Next, another embodiment will be described. (Fourth embodiment) The electromagnetic ultrasonic probes TRa to TRc and REa to REc in the first to third embodiments are configured with one coil 2Ta to 2Tc and 2Ra to 2Rc inside the first magnets 1Ta to 1Tc and 1Ra to 1Rc, but the electromagnetic ultrasonic probes TRd and REd in the fourth embodiment are configured with one coil 2Td and 2Rd arranged in the adjacent portion of two adjacent first magnets 1Td and 1Rd among the plurality of first magnets 1Td and 1Rd.

[0072] Fig. 6 is a diagram for explaining an electromagnetic ultrasonic probe system in the fourth embodiment, in which Fig. 6A is a perspective view and Fig. 6B is a longitudinal cross-sectional view (vertical cross-sectional view).

[0073] The electromagnetic ultrasonic probe system Sd in the fourth embodiment includes, for example, an electromagnetic ultrasonic probe TRd used for transmission and an electromagnetic ultrasonic probe REd used for reception, as shown in FIG.

[0074] The electromagnetic ultrasonic probe TRd (REd) includes a plurality of ring-shaped first magnets 1Td (1Rd) magnetized in the axial direction, and one coil 2Td (2Rd) made of a long conductive member wound in one direction.

[0075] The multiple first magnets 1Td (1Rd) are arranged side by side in the axial direction so that two adjacent first magnets 1Td (1Rd) are spaced a predetermined distance apart and face each other with the same poles. Each of the first magnets 1Td (1Rd) itself is similar to the first magnet 1Ta (1Ra) in the electromagnetic acoustic probe TRa (REa) of the first embodiment. In the example shown in FIG. 6, the multiple first magnets 1Td (1Rd) are made up of two 1A and 1B magnets 1Td-1, 1Td-2 (1Rd-1, 1Rd-2), which are arranged side by side with their north poles facing each other. The number of first magnets 1Td is not limited to this, and may be three or more.

[0076] The coil 2Td (2Rd) is disposed in the adjacent area AT (AR) between two adjacent first magnets 1Td (1Rd) in the axial direction among the plurality of first magnets 1Td (1Rd). The adjacent area AT (AR) is a space created by the axial separation between two adjacent first magnets 1Td (1Rd). As in the first to third embodiments, in the fourth embodiment, the coil 2Td (2Rd) is disposed at a position closer to the subject Ob in the radial direction than the first magnets 1Td (1Rd), as shown in FIG. 6B. The coil 2Td (2Rd) itself is similar to the coil 2Ta (2Ra) in the electromagnetic acoustic probe TRa (REa) of the first embodiment.

[0077] In addition, a cylindrical covering member made of a ferromagnetic material (such as silicon steel) may be disposed in the adjacent portion AT (AR) so as to cover the coil 2Td (2Rd). The covering member may be formed by continuously stacking a plurality of ferromagnetic thin plates formed in the shape of the cylindrical cross section in the circumferential direction in order to reduce eddy currents.

[0078] When ultrasonic testing is performed, as shown in FIG. 6A, an object Ob is inserted into a transmitting electromagnetic ultrasonic probe TRd and a receiving electromagnetic ultrasonic probe REd, and the transmitting electromagnetic ultrasonic probe TRd and the receiving electromagnetic ultrasonic probe REd are arranged at the positions of the coils 2Td and 2Rd with a predetermined gap in the axial direction.

[0079] In such a transmitting electromagnetic ultrasonic probe TRd, the first magnet 1Td generates a static magnetic field with magnetic field lines aligned radially to the object Ob in the adjacent region AT. When an AC current is applied to the coil 2Td, eddy currents are generated in the object Ob. The radial magnetic field lines in the static magnetic field and the eddy currents generate an axial Lorentz force, which excites ultrasonic waves as guide waves in the object Ob. This excited ultrasonic wave propagates through the object Ob. In the receiving electromagnetic ultrasonic probe REd, an AC current is generated in the object Ob due to the interaction between the vibration of the object Ob caused by the ultrasonic waves and the static magnetic field with magnetic field lines aligned radially, which is generated in the object Ob by the first magnet 1Rd. The fluctuating magnetic field (AC magnetic field) caused by this AC current generates a current in the coil 2Rd, and the fluctuating magnetic field is detected by the coil 2Rd.

[0080] A specific example (third specific example) of the fourth embodiment will be described. The subject Ob, the first A and first B magnets 1Td-1, 1Rd-1; 1Td-2, 1Rd-2, and the coils 2Td and 2Rd in this third specific example are identical in terms of dimensions and other conditions to the subject Ob, the first magnets 1Ta and 1Ra, and the coils 2Ta and 2Ra in the first specific example. The distance between the transmitting electromagnetic ultrasonic probe TRd and the receiving electromagnetic ultrasonic probe REd is 300 [mm] at the positions of the coils 2Td and 2Rd. The axial length (width) of the adjacent portions AT and AR is 1 [mm]. When an AC current, which is a 5-cycle burst wave at 1 [MHz], is applied to the transmitting electromagnetic ultrasonic probe TRd in this third specific example, an example of a received signal output from the receiving electromagnetic ultrasonic probe REd is shown in FIG. 7. Fig. 7 is a diagram showing an output signal of a receiving electromagnetic ultrasonic probe, as an example, in an electromagnetic ultrasonic probe system in the fourth embodiment. The horizontal axis of Fig. 7 represents time in milliseconds [ms], and the vertical axis represents signal magnitude (amplitude) in millivolts [mV]. As shown in Fig. 7, even if the object Ob is a non-magnetic stainless steel wire or bar with a relatively small diameter, it can be seen that ultrasonic waves of a guided wave are excited by the transmitting electromagnetic ultrasonic probe TRd, and the ultrasonic waves propagating through the stainless steel wire or bar can be received by the receiving electromagnetic ultrasonic probe REd.

[0081] As described above, in the first to third embodiments, a radial Lorentz force is generated by the static magnetic field of magnetic field lines along the axial direction generated in the subject Ob and eddy currents, thereby generating ultrasonic waves, while in the fourth embodiment described above, an axial Lorentz force is generated by the static magnetic field of magnetic field lines along the radial direction generated in the subject Ob and eddy currents, thereby generating ultrasonic waves.

[0082] As described above, the electromagnetic ultrasonic probe system Sd and the electromagnetic ultrasonic probes TRd, REd in the fourth embodiment have the coils 2Td, 2Rd arranged in the adjacent parts AT, AR, and therefore can generate a static magnetic field more appropriate for the object Ob, which becomes radial magnetic field lines for the eddy currents generated in the object Ob by the coils 2Td, 2Rd.

[0083] In the fourth embodiment, one coil 2Td, 2Rd is arranged for each of the plurality of first magnets 1Td, 1Rd. However, multiple coils 2Td, 2Rd may be arranged. That is, the first magnets 1T, 1R may be arranged in parallel in the axial direction so that two adjacent first magnets 1T, 1R face each other with the same poles, and the coils 2T, 2R may be arranged inside multiple adjacent portions AT, AR of two adjacent first magnets 1T, 1R in the axial direction. In such a case, the number of the multiple coils 2T, 2R may be fewer than the number of the multiple first magnets 1T, 1R. Since such electromagnetic ultrasonic probes TR, RE include multiple first magnets 1T, 1R and multiple coils 2T, 2R, they can generate stronger ultrasonic waves and select ultrasonic modes.

[0084] Next, another embodiment will be described. (Fifth embodiment) The electromagnetic ultrasonic probe systems Sa to Sd in the first to fourth embodiments are configured to include transmitting electromagnetic ultrasonic probes TRa to TRd and receiving electromagnetic ultrasonic probes REa to REd, which have the same configuration, whereas the electromagnetic ultrasonic probe system Se in the fifth embodiment is configured to include a transmitting electromagnetic ultrasonic probe TRe and a receiving electromagnetic ultrasonic probe REe, which have different configurations.

[0085] FIG. 8 is a perspective view for explaining the system of the electromagnetic ultrasonic probe according to the fifth embodiment.

[0086] The electromagnetic ultrasonic probe system Se in the fifth embodiment includes, for example, an electromagnetic ultrasonic probe TRe used for transmission and an electromagnetic ultrasonic probe REe used for reception, as shown in FIG.

[0087] The transmitting electromagnetic ultrasonic probe TRe includes a ring-shaped first magnet 1Te magnetized in the axial direction and a plurality of coils 2Te each made of a long conductor wound in one direction. The first magnet 1Te itself is the same as the first magnet 1Ta in the electromagnetic ultrasonic probe TRa of the first embodiment.

[0088] The multiple coils 2Te are disposed inside the first magnet 1Te and are juxtaposed at a predetermined interval in the axial direction so that the current flows alternately. Each of the individual coils 2Te is similar to the coil 2Ta in the electromagnetic ultrasonic probe TRa of the first embodiment. In the example shown in FIG. 8 , the multiple coils 2Te are composed of three coils, first through third coils 2Te-1, 2Te-2, and 2Te-3, which are juxtaposed at a predetermined interval in the axial direction so that the current in the first and third coils 2Te-1 and 2Te-3 flows counterclockwise as viewed from the axial direction from right to left on the paper, and the current in the second coil 2Te-2 flows clockwise as viewed from the axial direction from right to left on the paper. The number of coils 2Te is not limited to this, and may be four or more.

[0089] The receiving electromagnetic ultrasonic probe REe is the same as the receiving electromagnetic ultrasonic probe REa in the first embodiment.

[0090] When ultrasonic testing is performed, as shown in FIG. 8, an object Ob is inserted into the transmitting electromagnetic ultrasonic probe TRe and the receiving electromagnetic ultrasonic probe REe, and the transmitting electromagnetic ultrasonic probe TRe and the receiving electromagnetic ultrasonic probe REe are arranged at a predetermined interval in the axial direction, and function in the same manner as in the first embodiment.

[0091] As described above, in the electromagnetic ultrasonic probe system Se and the electromagnetic ultrasonic probes TRe, REe in the fifth embodiment, the coils 2Te, 2Re are arranged inside the first magnets 1Te, 1Re, and therefore, a static magnetic field more appropriate for the object Ob can be generated by magnetic field lines extending from the first magnetic pole formed on one end face of the first magnets 1Te, 1Re to the second magnetic pole formed on the other end face of the first magnets 1Te, 1Re, which serve as axial magnetic field lines for the eddy currents generated in the object Ob by the coils 2Te, 2Re.

[0092] The electromagnetic ultrasonic probe system Se and the electromagnetic ultrasonic probe TRe in the fifth embodiment include a plurality of coils 2Te, and therefore, it is possible to generate ultrasonic waves of a specific (desired) mode by interference between the ultrasonic waves generated by each of the coils 2Te. For example, the axial spacing between the plurality of coils 2Te is set according to the wavelength of the ultrasonic waves generated in the object Ob by the electromagnetic ultrasonic probe TRe. Preferably, the axial spacing between the plurality of coils 2Te is half the wavelength λ / 2 of the ultrasonic waves generated in the object Ob by the electromagnetic ultrasonic probe TRe. In this way, the ultrasonic waves with the wavelength λ are emphasized by interference between the ultrasonic waves generated by each of the coils 2Te, and it is possible to generate ultrasonic waves with the wavelength λ predominantly in the object Ob.

[0093] In the above-described fifth embodiment, the transmitting electromagnetic ultrasonic probe TRe is configured to include a plurality of coils 2Te, but the receiving electromagnetic ultrasonic probe REe may be configured to include a plurality of coils 2Re to enable reception of ultrasonic waves in a specific (desired) mode.

[0094] In the second to fourth embodiments described above, the coils 2Tb to 2Td in the transmitting electromagnetic ultrasonic probes TRb to TRd are one, but they may be multiple coils in order to enable transmission of ultrasonic waves in a specific (desired) mode, as in the fifth embodiment. In the second to fourth embodiments described above, the coils 2Rb to 2Rd in the receiving electromagnetic ultrasonic probes REb to REd are one, but they may be multiple coils in order to enable reception of ultrasonic waves in a specific (desired) mode, as in the fifth embodiment.

[0095] Next, another embodiment will be described. (Sixth embodiment) In order to enable the generation of ultrasonic waves in a specific (desired) mode, in the fifth embodiment, multiple coils 2Te were arranged inside one first magnet 1Te, but in the sixth embodiment, multiple sets (combinations) of one first magnet 1Tf, 1Rf and one coil 2Tf, 2Rf arranged inside the first magnet 1Tf, 1Rf are arranged side by side in the axial direction.

[0096] FIG. 9 is a perspective view for explaining an electromagnetic ultrasonic probe system according to the sixth embodiment.

[0097] The electromagnetic ultrasonic probe system Sf in the sixth embodiment includes, for example, an electromagnetic ultrasonic probe TRf used for transmission and an electromagnetic ultrasonic probe REf used for reception, as shown in FIG.

[0098] The electromagnetic ultrasonic probe TRf (REf) includes a plurality of ring-shaped first magnets 1Tf (1Rf) magnetized in the axial direction, and a plurality of coils 2Tf (2Rf) each made of a long conductive member wound in one direction.

[0099] The multiple first magnets 1Tf (1Rf) are arranged in parallel in the axial direction so that two adjacent first magnets 1Tf (1Rf) face each other with the same poles. Each of the first magnets 1Tf (1Rf) itself is similar to the first magnet 1Ta (1Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment. In the example shown in Figure 9, the multiple first magnets 1Tf (1Rf) consist of four 1A to 1D magnets 1Tf-1, 1Tf-2, 1Tf-3, 1Tf-4 (1Rf-1, 1Rf-2, 1Rf-3, 1Rf-4), with the 1A and 1B magnets 1Tf-1, 1Tf-2 (1Rf-1, 1Rf-2) arranged side by side with their north poles facing each other, the 1B and 1C first magnets 1Tf-2, 1Tf-3 (1Rf-2, 1Rf-3) arranged side by side with their south poles facing each other, and the 1C and 1D magnets 1Tf-3, 1Tf-4 (1Rf-3, 1Rf-4) arranged side by side with their north poles facing each other.

[0100] The plurality of coils 2Tf (2Rf) are arranged on the respective insides of the plurality of first magnets 1Tf (1Rf) in the axial direction. Therefore, as described above, one first magnet 1Tf, 1Rf and one coil 2Tf, 2Rf arranged on the inside of the first magnet 1Tf, 1Rf form one set. In the example shown in Fig. 9, the plurality of coils 2Tf (2Rf) are made up of four 1A to 1D coils 2Tf-1, 2Tf-2, 2Tf-3, 2Tf-4 (2Rf-1, 2Rf-2, 2Rf-3, 2Rf-4), and the coil 2Tf (2Rf) itself is similar to the coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0101] When ultrasonic flaw detection is performed, as shown in FIG. 9, an object Ob is inserted into a transmitting electromagnetic ultrasonic probe TRf and a receiving electromagnetic ultrasonic probe REf, and the transmitting electromagnetic ultrasonic probe TRf and the receiving electromagnetic ultrasonic probe REf are arranged at a predetermined interval in the axial direction, and each set functions in the same way as in the first embodiment.

[0102] As described above, the electromagnetic ultrasonic probe system Sf and the electromagnetic ultrasonic probes TRf, REf in the sixth embodiment have a plurality of coils 2Tf, 2Rf arranged inside each of a plurality of first magnets 1Tf, 1Rf, so that magnetic field lines extending from a first magnetic pole formed on one end face of the first magnets 1Tf, 1Rf to a second magnetic pole formed on the other end face of the first magnets 1Tf, 1Rf form axial magnetic field lines for the eddy currents generated in the subject Ob by the coils 2Tf, 2Rf, thereby generating a static magnetic field more appropriate for the subject Ob.

[0103] The electromagnetic ultrasonic probe system Sf and the electromagnetic ultrasonic probe TRf in the sixth embodiment include a plurality of coils 2Tf, and therefore, due to the interference of the ultrasonic waves generated by each of the coils 2Tf, it is possible to generate ultrasonic waves in a specific (desired) mode at a specific (desired) velocity. For example, the axial spacing of the plurality of coils 2Tf is set according to the wavelength of the ultrasonic waves generated in the object Ob by the electromagnetic ultrasonic probe TRf. Preferably, the axial spacing of the plurality of coils 2Tf is half the wavelength λ / 2 of the ultrasonic waves generated in the object Ob by the electromagnetic ultrasonic probe TRf. In this way, the ultrasonic waves with the wavelength λ are emphasized due to the interference of the ultrasonic waves generated by each of the coils 2Tf, and the ultrasonic waves with the wavelength λ can be generated predominantly in the object Ob.

[0104] On the other hand, the electromagnetic ultrasonic probe system Sf and the electromagnetic ultrasonic probe REf in the sixth embodiment include a plurality of coils 2Rf, and therefore can receive ultrasonic waves in a specific (desired) mode. For example, the axial spacing of the plurality of coils 2Rf is set according to the wavelength of the ultrasonic waves to be received by the electromagnetic ultrasonic probe REf. Preferably, the axial spacing of the plurality of coils 2Rf is half the wavelength λ / 2 of the ultrasonic waves to be received by the electromagnetic ultrasonic probe REf. This allows ultrasonic waves with a wavelength λ to be selectively received.

[0105] In the sixth embodiment described above, the coils 2Tf and 2Rf are arranged inside the first magnets 1Tf and 1Rf, but as in the fourth embodiment, the coils 2Tf and 2Rf may be arranged in the adjacent portions of two adjacent first magnets.

[0106] Furthermore, in the sixth embodiment described above, one first magnet 1Tf, 1Rf and one coil 2Tf, 2Rf arranged inside the first magnet 1Tf, 1Rf form one set, but one first magnet 1Tf, 1Rf and multiple coils 2Tf, 2Rf arranged inside the first magnets 1Tf, 1Rf may also form one set. That is, there may be multiple coils 2Tf, 2Rf arranged inside each of the multiple first magnets 1Tf, 1Rf in the axial direction.

[0107] In the sixth embodiment, the two adjacent first magnets 1Tf, 1Rf may be spaced apart or may be in close contact with each other. In such cases, the axial length (width) of the first magnets 1Tf, 1Rf is adjusted according to the axial spacing of the multiple coils 2Tf.

[0108] Furthermore, in the first to sixth embodiments described above, the number of first magnets 1T in the transmitting electromagnetic ultrasonic probe TR and the number of first magnets 1R in the receiving electromagnetic ultrasonic probe RE are the same, but they may be different numbers. For example, the transmitting electromagnetic ultrasonic probe TR includes two first magnets 1T, and the receiving electromagnetic ultrasonic probe RE includes one first magnet 1R.

[0109] Furthermore, in the above description, the fifth embodiment has been exemplified as an electromagnetic ultrasonic probe system Se including a transmitting electromagnetic ultrasonic probe TRe and a receiving electromagnetic ultrasonic probe REe which are configured differently from each other, but an electromagnetic ultrasonic probe system S may be configured which includes a transmitting electromagnetic ultrasonic probe TR of any of the transmitting electromagnetic ultrasonic probes TRa to TRf in the first to sixth embodiments, and a receiving electromagnetic ultrasonic probe RE of any of the receiving electromagnetic ultrasonic probes REa to REf in the first to sixth embodiments which is different from the transmitting one.

[0110] Next, another embodiment will be described. (Seventh embodiment) While the electromagnetic ultrasonic probes TRa to TRf and REa to REf in the first to sixth embodiments are each configured with only the first magnets 1Ta to 1Tf and 1Ra to 1Rf magnetized in the axial direction, the electromagnetic ultrasonic probes TRg and REg in the seventh embodiment are further configured with the second magnets 1Tg-2 and 1Rg-2 magnetized in the radial direction.

[0111] Fig. 10 is a diagram for explaining the system of an electromagnetic ultrasonic probe and the analysis results of the magnetic field in the seventh embodiment. Fig. 10A is a perspective view of the electromagnetic ultrasonic probe, and Fig. 10B is a longitudinal cross-sectional view (vertical cross-sectional view) thereof. Since the transmitting electromagnetic ultrasonic probe TRg and the receiving electromagnetic ultrasonic probe REg have the same structure, Fig. 10A and Fig. 10B show the transmitting electromagnetic ultrasonic probe TRg, and the reference numerals of the components of the receiving electromagnetic ultrasonic probe REg are written in parentheses after the reference numerals of the components of the transmitting electromagnetic ultrasonic probe TRg that correspond to the reference numerals of the receiving electromagnetic ultrasonic probe REg. The same applies to Figs. 14 to 17 in the eighth to tenth embodiments described later. Fig. 10C shows the results of analyzing the magnetic field of the electromagnetic ultrasonic probe TRg (REg) of one example (first example) in the electromagnetic ultrasonic probe system of the seventh embodiment, where the arrows (→) indicate magnetic field lines and their directions, and the shading indicates the magnitude of the magnetic flux density, with the lighter the shading, the greater the magnetic flux density. Note that Fig. 10A shows the region SC of the magnetic field analysis shown in Fig. 10C. The same applies to Figs. 11 to 16.

[0112] The electromagnetic ultrasonic probe system Sg in the seventh embodiment includes, for example, an electromagnetic ultrasonic probe TRg used for transmission and an electromagnetic ultrasonic probe REg used for reception, as shown in FIG.

[0113] The electromagnetic ultrasonic probe TRg (REg) comprises a ring-shaped first magnet 1Tg-1 (1Rg-1) magnetized in the axial direction, a ring-shaped second magnet 1Tg-2 (1Rg-2) magnetized in the radial direction, and one coil 2Tg (2Rg) made of a long conductor material wound in one direction.

[0114] The first magnet 1Tg-1 (1Rg-1) is the same as the first magnet 1Ta (1Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0115] In this embodiment, the second magnet 1Tg-2 (1Rg-2) is a permanent magnet that is magnetized in the radial direction, for example, from the viewpoint of power saving. Because the second magnet 1Tg-2 (1Rg-2) is magnetized in the radial direction, a first magnetic pole (e.g., N pole) is formed on the outer circumferential surface, and a second magnetic pole (e.g., S pole) different from the first magnetic pole is formed on the inner circumferential surface.

[0116] The second magnet 1Tg-2 (1Rg-2) is juxtaposed in the axial direction to the first magnet 1Tg-1 (1Rg-1) on the side of one axial end face so that the magnetic pole of one axial end face of the first magnet 1Tg-1 (1Rg-1) and the magnetic pole of the inner circumferential surface of the second magnet 1Tg-2 (1Rg-2) are the same polarity. In the example shown in FIG. 10, the magnetic pole of one end face of the first magnet 1Tg-1 (1Rg-1) is an S pole, and the magnetic pole of the inner circumferential surface of the second magnet 1Tg-2 (1Rg-2) is an S pole, and these S poles are the same polarity. The magnetic pole of the other axial end face of the first magnet 1Tg-1 (1Rg-1) is an N pole because it is magnetized in the axial direction, and the magnetic pole of the outer circumferential surface of the second magnet 1Tg-2 (1Rg-2) is an N pole because it is magnetized in the radial direction. In this embodiment, the first magnet 1Tg-1 (1Rg-1) and the second magnet 1Tg-2 (1Rg-2) are formed with the same inner diameter and outer diameter, but the inner diameter and outer diameter do not have to be the same size.

[0117] The coil 2Tg (2Rg) is one that is arranged inside the first magnet 1Tg-1 (1Rg-1), and is similar to the coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0118] When ultrasonic testing is performed, the object Ob is inserted into the transmitting electromagnetic ultrasonic probe TRg and the receiving electromagnetic ultrasonic probe REg, and the transmitting electromagnetic ultrasonic probe TRg and the receiving electromagnetic ultrasonic probe REg are arranged at a predetermined distance in the axial direction, and function in the same manner as in the first embodiment.

[0119] The electromagnetic ultrasonic probe TRg in the seventh embodiment further includes a second magnet 1Tg-2 axially juxtaposed to the first magnet 1Tg-1, so that a stronger static magnetic field (static magnetic field with high magnetic flux density) can be formed, and an ultrasonic flaw detection device D using this can generate stronger ultrasonic waves. The ultrasonic flaw detection device D using the electromagnetic ultrasonic probe TRg in the seventh embodiment will be described in the eleventh embodiment, which will be described later. The ultrasonic flaw detection device D using the electromagnetic ultrasonic probes TRh to TRj in the eighth to tenth embodiments, which will be described later, will also be described in the eleventh embodiment, which will be described later.

[0120] The static magnetic field will be described using an example and a comparative example. FIG. 11 is a diagram for explaining the analysis results of the magnet and magnetic field in the comparative example. FIG. 11A is a perspective view showing one magnet 1Ta (1Ra) in the comparative example (first comparative example), and FIG. 11B is the analysis results of the magnetic field. FIG. 12 is a diagram for explaining the analysis results of the electromagnetic ultrasonic probe and magnetic field of one example in the electromagnetic ultrasonic probe system of the second embodiment. FIG. 12A shows the electromagnetic ultrasonic probe of the example (second example), and FIG. 12B is the analysis results of the magnetic field. FIG. 13 is a diagram for explaining the analysis results of the electromagnetic ultrasonic probe and magnetic field of one comparative example in the electromagnetic ultrasonic probe system of the seventh embodiment. FIG. 13A shows the electromagnetic ultrasonic probe of the comparative example (second comparative example), and FIG. 13B is the analysis results of the magnetic field. 11B, 12B, and 13B, arrows (→) indicate magnetic lines of force and their directions, and the shading indicates the magnitude of the magnetic flux density, with the lighter the shading, the greater the magnetic flux density.

[0121] In the first comparative example, a first magnet 1Tg-1 (1Rg-1) was used for the single magnet 1Ta (1Ra), as shown in FIG. 11A. In the second comparative example, a magnet 1Tg'-1 (1Rg'-1) arranged with its axial orientation reversed is used instead of the first magnet 1Tg-1 of the seventh embodiment, as shown in FIG. 13A. Therefore, in the second comparative example, the second magnet 1Tg-2 (1Rg-2) is juxtaposed in the axial direction on the side of one axial end face of the magnet 1Tg'-1 (1Rg'-1) so that the magnetic poles on one axial end face of the magnet 1Tg-2 (1Rg-2) are opposite polarities to the magnetic poles on the inner circumferential surface of the second magnet 1Tg-2 (1Rg-2). In other words, in the second comparative example, the second magnet 1Tg-2 (1Rg-2) is juxtaposed in the axial direction on the side of one end face of the magnet 1Tg'-1 (1Rg'-1) so that the magnetic poles of one end face of the magnet 1Tg'-1 (1Rg'-1) in the axial direction and the magnetic poles of the outer peripheral surface of the second magnet 1Tg-2 (1Rg-2) are the same polarity.

[0122] The first magnet 1Tg-1 (1Rg-1) of the first embodiment, the magnet 1Ta (1Ra) of the first comparative example, the first magnets 1Tb-1 and 1Tb-2 (1Rb-1 and 1Rb-2) of the second embodiment, and the magnet 1Tg'-1 (1Rg'-1) of the second comparative example each have an outer diameter of 28 mm, an inner diameter of 15 mm, an axial length of 15 mm, a relative permeability of 1.05, and a residual magnetic flux density of 1.29 T. The second magnet 1Tg-2 (1Rg-2) in each of the first embodiment and the second comparative example each have an outer diameter of 28 mm, an inner diameter of 15 mm, an axial length of 15 mm, a relative permeability of 1.05, and a residual magnetic flux density of 1.29 T. The specimen Ob is a stainless steel wire or round bar with a diameter of 12 mm, a length of 100 mm, and a relative permeability of 1. In the first comparative example, the magnet 1Ta (1Ra) was positioned so that its axial center position was located at the axial center position of the subject Ob, and in the first example, the second example, and the second comparative example, the two magnets were positioned so that the axial center positions of the two magnets were located at the axial center position of the subject Ob. In the first example, the second example, and the second comparative example, the distance between the two magnets was 1 mm. The smaller (shorter) the distance between the two magnets, the better. Ansoft's Maxwell, a general-purpose finite element method magnetic field analysis tool, was used to analyze the magnetic field.

[0123] In the first comparative example, the maximum magnetic flux density was approximately 0.34 [T], as shown in FIG. 11B. In contrast, in the second example, the maximum magnetic flux density was approximately 0.47 [T], as shown in FIG. 12B, and a static magnetic field higher than the magnetic flux density of the first comparative example was formed. In the first example, the maximum magnetic flux density was approximately 0.622 [T], as shown in FIG. 10C, and a static magnetic field even higher than the magnetic flux density of the first comparative example was formed. On the other hand, in the second comparative example, in which the axial direction was reversed compared to the first example, the maximum magnetic flux density was approximately 0.56 [T], as shown in FIG. 13B, but the magnetic flux density at the location where coil 2Tg (2Rg) was located was approximately 0.39 [T], which was lower than those of the first and second examples.

[0124] Next, another embodiment will be described. (Eighth embodiment) In the seventh embodiment, the electromagnetic ultrasonic probes TRg and REg are configured to include second magnets 1Tg-2 and 1Rg-2 magnetized in the radial direction, while the electromagnetic ultrasonic probes TRh and REh in the eighth embodiment are further configured to include third magnets 1Th-1 and 1Rh-1 magnetized in the radial direction.

[0125] Fig. 14 is a diagram for explaining the electromagnetic ultrasonic probe system and the analysis results of the magnetic field in the eighth embodiment. Fig. 14A is a perspective view of the electromagnetic ultrasonic probe, and Fig. 14B is a longitudinal cross-sectional view (vertical cross-sectional view) thereof. Fig. 14C shows the analysis results of the magnetic field of the electromagnetic ultrasonic probe TRh (REh) of one example (third example) in the electromagnetic ultrasonic probe system of the eighth embodiment, where arrows (→) indicate magnetic field lines and their directions, and shading indicates the magnitude of the magnetic flux density, with lighter shading indicating greater magnetic flux density.

[0126] The electromagnetic ultrasonic probe system Sh in the eighth embodiment includes, for example, an electromagnetic ultrasonic probe TRh used for transmission and an electromagnetic ultrasonic probe REh used for reception, as shown in FIG.

[0127] The electromagnetic ultrasonic probe TRh (REh) comprises a ring-shaped third magnet 1Th-1 (1Rh-1) magnetized in the radial direction, a ring-shaped first magnet 1Th-2 (1Rh-2) magnetized in the axial direction, a ring-shaped second magnet 1Th-3 (1Rh-3) magnetized in the radial direction, and one coil 2Th (2Rh) made of a long conductor member wound in one direction.

[0128] The first magnet 1Th-2 (1Rh-2) is the same as the first magnet 1Ta (1Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0129] The second magnet 1Th-3 (1Rh-3) is similar to the second magnet 1Tg-2 (1Rg-2) in the electromagnetic acoustic probe TRg (REg) of the seventh embodiment. In the example shown in Fig. 14, similar to the seventh embodiment shown in Fig. 10, the magnetic pole on one end surface of the first magnet 1Th-2 (1Rh-2) is an S pole, and the magnetic pole on the inner peripheral surface of the second magnet 1Th-3 (1Rh-3) is an S pole, and these S poles are the same polarity.

[0130] In this embodiment, the third magnet 1Th-1 (1Rh-1) is a permanent magnet that is magnetized in the radial direction, for example, from the viewpoint of power saving. Because the third magnet 1Th-1 (1Rh-1) is magnetized in the radial direction, a first magnetic pole (e.g., N pole) is formed on the inner peripheral surface, and a second magnetic pole (e.g., S pole) different from the first magnetic pole is formed on the outer peripheral surface.

[0131] The third magnet 1Th-1 (1Rh-1) is juxtaposed in the axial direction to the first magnet 1Th-2 (1Rh-2) on the side of the other end face so that the magnetic pole of the other axial end face of the first magnet 1Th-2 (1Rh-2) and the magnetic pole of the inner peripheral surface of the third magnet 1Th-1 (1Rh-1) are the same polarity. In the example shown in Figure 14, the magnetic pole of the other end face of the first magnet 1Th-2 (1Rh-2) is an N pole, and the magnetic pole of the inner peripheral surface of the third magnet 1Th-1 (1Rh-1) is an N pole, and these N poles are the same polarity. The magnetic pole of the outer peripheral surface of the third magnet 1Th-1 (1Rh-1) is magnetized in the radial direction, so it is an S pole. In this embodiment, the first magnet 1Th-2 (1Rh-2), the second magnet 1Th-3 (1Rh-3), and the third magnet 1Th-1 (1Rh-1) are formed with the same inner diameter and the same outer diameter, but the inner diameter and the outer diameter do not have to be the same size.

[0132] The coil 2Th (2Rh) is one that is arranged inside the first magnet 1Th-2 (1Rh-2), and is similar to the coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0133] When ultrasonic testing is performed, the object Ob is inserted into the transmitting electromagnetic ultrasonic probe TRh and the receiving electromagnetic ultrasonic probe REh, and the transmitting electromagnetic ultrasonic probe TRh and the receiving electromagnetic ultrasonic probe REh are arranged at a predetermined interval in the axial direction, and function in the same manner as in the first embodiment.

[0134] The electromagnetic ultrasonic probe TRh in the eighth embodiment further includes second and third magnets 1Th-3 and 1Th-1, which are respectively arranged axially in parallel with the first magnet 1Th-2, and therefore can form a stronger static magnetic field (a static magnetic field with a high magnetic flux density), and the ultrasonic flaw detection device D using this can generate stronger ultrasonic waves.

[0135] The static magnetic field will be described using one example (third example). The first and second magnets 1Th-2 and 1Th-3 (1Rh-2 and 1Rh-3) in the third example are similar to the first and second magnets 1Tg-1 and 1Tg-2 (1Rg-1 and 1Rg-2) in the first example. The third magnet 1Th-1 in the third example also has an outer diameter of 28 mm, an inner diameter of 15 mm, an axial length of 15 mm, a relative permeability of 1.05, and a residual magnetic flux density of 1.29 T. The subject Ob is also similar to the first example. In the third example, the third, first, and second magnets 1Th-1, 1Th-2, and 1Th-3 (1Rh-1, 1Rh-2, and 1Rh-3) are arranged so that the axial center position of the first magnet 1Th-2 is located at the axial center position of the subject Ob. In the third embodiment, the interval between each pair of magnets in the third, first and second magnets 1Th-1, 1Th-2, 1Th-3 (1Rh-1, 1Rh-2, 1Rh-3) is 1 mm.

[0136] In this third embodiment, the maximum magnetic flux density is approximately 0.67 T, as shown in Fig. 14C, and a static magnetic field higher than that of Example 1 is formed. As can be seen from a comparison of Fig. 10C and Fig. 14C, the magnetic flux density distribution of the third embodiment is more uniform than that of Example 1, and the high magnetic flux density region is wider in Example 3 than in Example 1.

[0137] Next, another embodiment will be described. (Ninth embodiment) In the seventh embodiment, the electromagnetic ultrasonic probes TRg, REg are configured by arranging radially magnetized second magnets 1Tg-2, 1Rg-2 in the axial direction relative to the first magnets 1Tg-1, 1Rg-1, but the electromagnetic ultrasonic probes TRi, REi; TRj, REj in the ninth and tenth embodiments are configured by arranging radially magnetized fourth magnets in the radial direction relative to the first magnets at each location where the first magnets face each other with the same poles. The electromagnetic ultrasonic probes TRi, REi in the ninth embodiment have one location where the first magnets face each other with the same poles, while the electromagnetic ultrasonic probes TRj, REj in the tenth embodiment have two locations where the first magnets face each other with the same poles.

[0138] Fig. 15 is a diagram for explaining the electromagnetic ultrasonic probe system and the analysis results of the magnetic field in the ninth embodiment. Fig. 15A is a perspective view of the electromagnetic ultrasonic probe, and Fig. 15B is a longitudinal cross-sectional view (vertical cross-sectional view) thereof. Fig. 15C shows the analysis results of the magnetic field of the electromagnetic ultrasonic probe TRi (REi) of one example (fourth example) in the electromagnetic ultrasonic probe system of the ninth embodiment, where arrows (→) indicate magnetic field lines and their directions, and shading indicates the magnitude of the magnetic flux density, with lighter shading indicating greater magnetic flux density.

[0139] The electromagnetic ultrasonic probe system Si in the ninth embodiment includes, for example, an electromagnetic ultrasonic probe TRi used for transmission and an electromagnetic ultrasonic probe REi used for reception, as shown in FIG.

[0140] The electromagnetic ultrasonic probe TRi (REi) comprises two ring-shaped first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) magnetized in the axial direction, one ring-shaped fourth magnet 1Ti-2 (1Ri-2) magnetized in the radial direction, and one coil 2Ti (2Ri) made of a long conductor member wound in one direction.

[0141] The two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) are arranged side by side in the axial direction so that their poles face each other, similar to the multiple first magnets 1Tb (1Rb) in the second embodiment. In the example shown in Fig. 15, the two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) are arranged side by side so that their south poles face each other. These first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) are similar to the first magnets 1Ta (1Ra) in the electromagnetic ultrasonic probe TRa (REa) in the first embodiment.

[0142] In this embodiment, the fourth magnet 1Ti-2 (1Ri-2) is a permanent magnet that is magnetized in the radial direction, for example, from the viewpoint of power saving. Because the fourth magnet 1Ti-2 (1Ri-2) is magnetized in the radial direction, a first magnetic pole (e.g., an N pole) is formed on the outer peripheral surface, and a second magnetic pole (e.g., an S pole) different from the first magnetic pole is formed on the inner peripheral surface.

[0143] The fourth magnet 1Ti-2 (1Ri-2) is arranged radially adjacent to the outer periphery of the two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) at a location where the same poles of the two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) face each other so that the same pole and the magnetic pole of the inner circumferential surface of the fourth magnet 1Ti-2 (1Ri-2) are the same pole. In the example shown in Fig. 15, the fourth magnet 1Ti-2 (1Ri-2) is arranged radially adjacent to the outer periphery of the two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) at a location where the two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) face each other with their south poles facing each other so that the magnetic pole of its inner circumferential surface is the south pole. The fourth magnet 1Ti-2 (1Ri-2) is arranged so as to cover a portion of each of the south pole sides of the two first magnets 1Ti-1 and 1Ti-3 (1Ri-1 and 1Ri-3).

[0144] Coil 2Ti (2Ri) is one of the two first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) arranged inside one of them, and is similar to coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0145] When ultrasonic testing is performed, an object Ob is inserted into the transmitting electromagnetic ultrasonic probe TRi and the receiving electromagnetic ultrasonic probe REi, and the transmitting electromagnetic ultrasonic probe TRi and the receiving electromagnetic ultrasonic probe REi are arranged at a predetermined interval in the axial direction, and function in the same manner as in the first embodiment.

[0146] The electromagnetic ultrasonic probe TRi in the ninth embodiment further includes a fourth magnet 1Ti-2 arranged radially adjacent to the outer periphery of the first magnets 1Ti-1 and 1Ti-3 at a location where the first magnets 1Ti-1 and 1Ti-3 face each other with the same poles, thereby forming a stronger static magnetic field (a static magnetic field with a high magnetic flux density) and generating stronger ultrasonic waves.

[0147] The static magnetic field will be described using one example (fourth example). The first magnets 1Ti-1 and 1Ti-3 (1Ri-1 and 1Ri-3) in the fourth example are the same as the first magnets 1Tg-1 (1Rg-1) in the first example. The fourth magnet 1Ti-2 (1Ri-2) in the fourth example has an outer diameter of 52 mm, an inner diameter of 32 mm, an axial length of 14 mm, a relative permeability of 1.05, and a residual magnetic flux density of 1.29 T. The subject Ob is also the same as in the first example. In the fourth embodiment, the first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) are spaced 4 mm apart in the axial direction, and are arranged so that the axial center of the first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) is located at the axial center of the subject Ob, and the fourth magnet 1Ti-2 (1Ri-2) is arranged so that its axial center is located at the axial center of the subject Ob. Therefore, the fourth magnet 1Ti-2 (1Ri-2) covers a portion of the south pole side of each of the first magnets 1Ti-1, 1Ti-3 (1Ri-1, 1Ri-3) by 5 mm.

[0148] In the fourth embodiment, the maximum magnetic flux density is approximately 0.617 T, as shown in Fig. 15C, and a static magnetic field is formed that is substantially the same as the magnetic flux density in the first embodiment and higher than the magnetic flux density in the first comparative example. As can be seen from a comparison of Fig. 10C and Fig. 15C, the magnetic flux density distribution in the fourth embodiment is more uniform than that in the first embodiment, and the high magnetic flux density region is wider in the fourth embodiment than in the first embodiment.

[0149] On the other hand, as can be seen from a comparison between FIG. 14C and FIG. 15C, the magnetic flux density distribution in the fourth embodiment is more uniform than that in the third embodiment, and the high magnetic flux density region is wider in the fourth embodiment than in the third embodiment.

[0150] Next, another embodiment will be described. (Tenth embodiment) Fig. 16 is a diagram for explaining the electromagnetic ultrasonic probe system and the analysis results of the magnetic field in the tenth embodiment. Fig. 16A is a perspective view of the electromagnetic ultrasonic probe, and Fig. 16B is a longitudinal cross-sectional view (vertical cross-sectional view) thereof. Fig. 16C shows the analysis results of the magnetic field of an electromagnetic ultrasonic probe TRj (REj) of one example (fifth example) in the electromagnetic ultrasonic probe system of the tenth embodiment, where arrows (→) indicate magnetic field lines and their directions, and shading indicates the magnitude of magnetic flux density, with lighter shading indicating greater magnetic flux density.

[0151] The electromagnetic ultrasonic probe system Sj in the tenth embodiment includes, for example, an electromagnetic ultrasonic probe TRj used for transmission and an electromagnetic ultrasonic probe REj used for reception, as shown in FIG.

[0152] The electromagnetic ultrasonic probe TRj (REj) comprises three ring-shaped first magnets 1Tj-1, 1Tj-3, 1Tj-5 (1Rj-1, 1Rj-3, 1Rj-5) magnetized in the axial direction, two ring-shaped fourth magnets 1Tj-2, 1Tj-4 (1Rj-2, 1Rj-4) magnetized in the radial direction, and one coil 2Tj (2Rj) made of a long conductor material wound in one direction.

[0153] The three first magnets 1Tj-1, 1Tj-3, 1Tj-5 (1Rj-1, 1Rj-3, 1Rj-5) are sequentially arranged side by side in the axial direction so that their poles face each other, similar to the multiple first magnets 1Tb (1Rb) in the second embodiment. In the example shown in FIG. 16, the two first magnets 1Tj-1, 1Tj-3 (1Rj-1, 1Rj-3) are arranged side by side with their north poles facing each other, and the two first magnets 1Tj-3, 1Tj-5 (1Rj-3, 1Rj-5) are arranged side by side with their south poles facing each other. These first magnets 1Tj-1, 1Tj-3, 1Tj-5 (1Rj-1, 1Rj-3, 1Rj-5) are similar to the first magnets 1Ta (1Ra) in the electromagnetic acoustic probe TRa (REa) in the first embodiment.

[0154] The fourth magnets 1Tj-2, 1Tj-4 (1Rj-2, 1Rj-4) are arranged radially adjacent to the outer periphery of the two first magnets facing each other with the same pole, at each position in the axial direction where two adjacent first magnets face each other with the same pole, so that the poles of the same poles and the magnetic poles of the inner circumferential surfaces of the fourth magnets are the same pole. In the example shown in Fig. 16, at a position (first position) where the two first magnets 1Tj-1, 1Tj-3 (1Rj-1, 1Rj-3) face each other with their north poles facing each other, the fourth magnet 1Tj-2 (1Rj-2) is arranged radially adjacent to the outer periphery of the two first magnets 1Tj-1, 1Tj-3 (1Rj-1, 1Rj-3) so that the magnetic pole of its inner circumferential surface is the north pole. The fourth magnet 1Tj-2 (1Rj-2) is arranged so as to cover a portion of each of the north pole sides of the two first magnets 1Tj-1, 1Tj-3 (1Rj-1, 1Rj-3). At the location (second location) where the south poles of the two first magnets 1Tj-3, 1Tj-5 (1Rj-3, 1Rj-5) face each other, the fourth magnet 1Tj-4 (1Rj-4) is radially juxtaposed on the outer periphery of the two first magnets 1Tj-3, 1Tj-5 (1Rj-3, 1Rj-5) so that the magnetic pole of its inner circumferential surface is the south pole. The fourth magnet 1Tj-4 (1Rj-4) is arranged so as to cover a portion of each of the south pole sides of the two first magnets 1Tj-3, 1Tj-5 (1Rj-3, 1Rj-5). The fourth magnet 1Tj-4 (1Rj-4) is similar to the fourth magnet 1Ti-2 (1Ri-2) of the ninth embodiment, and the fourth magnet 1Tj-2 (1Rj-2) is similar to the fourth magnet 1Ti-2 (1Ri-2) of the ninth embodiment except that the magnetization direction in the radial direction is opposite.

[0155] The coil 2Tj (2Rj) is one that is arranged inside any of the first magnets. In the example shown in Fig. 16, the coil 2Tj (2Rj) is one that is arranged inside any of the three first magnets 1Tj-1, 1Tj-3, 1Tj-5 (1Rj-1, 1Rj-3, 1Rj-5), and is preferably arranged inside the first magnet 1Tj-3 that is located at the center in the axial direction. The coil 2Tj (2Rj) is similar to the coil 2Ta (2Ra) in the electromagnetic ultrasonic probe TRa (REa) of the first embodiment.

[0156] When ultrasonic testing is performed, an object Ob is inserted into the transmitting electromagnetic ultrasonic probe TRj and the receiving electromagnetic ultrasonic probe REj, and the transmitting electromagnetic ultrasonic probe TRj and the receiving electromagnetic ultrasonic probe REj are arranged at a predetermined interval in the axial direction, and function in the same manner as in the first embodiment.

[0157] The electromagnetic ultrasonic probe TRj in the tenth embodiment further includes fourth magnets 1Tj-2 and 1Tj-4 arranged radially on the outer periphery at each of the locations of the first magnets 1Tj-1, 1Tj-3, and 1Tj-5 that face each other with the same poles, thereby forming a stronger static magnetic field (a static magnetic field with a high magnetic flux density) and generating stronger ultrasonic waves.

[0158] The static magnetic field will be described using one embodiment (fifth embodiment). The first magnets 1Tj-1, 1Tj-3, 1Tj-5 (1Rj-1, 1Rj-3, 1Rj-5) in the fifth embodiment are similar to the first magnet 1Tg-1 (1Rg-1) in the first embodiment. The fourth magnets 1Tj-2, 1Tj-4 (1Rj-2, 1Rj-4) in the fifth embodiment are similar to the fourth magnet 1Ti-2 (1Ri-2) in the fourth embodiment. The subject Ob is also similar to the first embodiment. In the fifth embodiment, the first magnets 1Tj-1 and 1Tj-3 (1Rj-1 and 1Rj-3) are spaced apart by 4 mm in the axial direction, as in the fourth embodiment, and the first magnets 1Tj-3 and 1Tj-5 (1Rj-3 and 1Rj-5) are spaced apart by 4 mm in the axial direction. These first magnets 1Tj-1, 1Tj-3 and 1Tj-5 (1Rj-1, 1Rj-3 and 1Rj-5) are arranged such that the central position of the central first magnet 1Tj-3 (1Rj-3) in the axial direction is the same as that of the subject. The fourth magnet 1Tj-2 (1Rj-2) is arranged so that its axial center position is located at the axial center position between the first magnets 1Tj-1 and 1Tj-3 (1Rj-1 and 1Rj-3), and the fourth magnet 1Tj-4 (1Rj-4) is arranged so that its axial center position is located at the axial center position between the first magnets 1Tj-3 and 1Tj-5 (1Rj-3 and 1Rj-5). Therefore, the fourth magnet 1Tj-2 (1Rj-2) covers a portion of each north pole side of the first magnets 1Tj-1, 1Tj-3 (1Rj-1, 1Rj-3) by 5 mm each, and the fourth magnet 1Tj-4 (1Rj-4) covers a portion of each south pole side of the first magnets 1Tj-3, 1Tj-5 (1Rj-3, 1Rj-5) by 5 mm each.

[0159] In the fifth embodiment, the maximum magnetic flux density is approximately 0.89 [T] as shown in FIG. 16C, and a static magnetic field having a higher magnetic flux density than that of the first comparative example can be formed.

[0160] In the tenth embodiment, the electromagnetic ultrasonic probes TRj and REj are provided with three first magnets 1Tj-1, 1Tj-3, 1Tj-5, 1Rj-1, 1Rj-3, and 1Rj-5, and correspondingly two fourth magnets 1Tj-2, 1Tj-4, 1Rj-2, and 1Rj-4, but the number of first magnets may be four or more, and the number of fourth magnets may be three or more accordingly.

[0161] Furthermore, in the seventh to tenth embodiments, the electromagnetic ultrasonic probes TRg to TRj, REg to REj are configured with one coil 2Tg to 2Tj, 2Rg to 2Rj, but instead of the one coil 2Tg to 2Tj, 2Rg to 2Rj, they may be configured with a plurality of coils arranged side by side in the axial direction so that the directions of current flow alternate.

[0162] In addition, in the seventh to tenth embodiments, a single ring-shaped permanent magnet is used for the second to fourth magnets 1Tg-2 (1Rg-2), 1Th-3 (1Rh-3); 1Th-1 (1Rh-1); 1Ti-2 (1Ri-2), 1Tj-2, and 1Tj-4 (1Rj-2, 1Rj-4). However, the second to fourth magnets 1Tg-2 (1Rg-2), 1Th-3 (1Rh-3); 1Th-1 (1Rh-1); 1Ti-2 (1Ri-2), 1Tj-2, and 1Tj-4 (1Rj-2, 1Rj-4) may each be formed of a plurality of segment magnets arranged sequentially in the circumferential direction to form a ring (variant). The segment magnets are formed by two imaginary planes that intersect at a predetermined angle along the axial direction, and have the shape of a portion of a cylinder cut out with the intersection line of the two planes aligned with the axis. The predetermined angle in the two planes is the central angle of the segment magnets. In such electromagnetic ultrasonic probes TRg to TRj, REg to REj, second through fourth magnets 1Tg-2 (1Rg-2), 1Th-3 (1Rh-3); 1Th-1 (1Rh-1); 1Ti-2 (1Ri-2), 1Tj-2, 1Tj-4 (1Rj-2, 1Rj-4) are formed using a plurality of segment magnets, so that second through fourth magnets 1Tg-2 (1Rg-2), 1Th-3 (1Rh-3); 1Th-1 (1Rh-1); 1Ti-2 (1Ri-2), 1Tj-2, 1Tj-4 (1Rj-2, 1Rj-4) can be easily produced.

[0163] Fig. 17 is a perspective view for explaining modified forms of the second magnet in the electromagnetic ultrasonic probe of the seventh embodiment. Fig. 17A shows electromagnetic ultrasonic probes TRga and REga equipped with modified second magnets, and Fig. 17B shows one segment magnet 1Tga-21 (1Tga-22 to 1Tga-24, 1Rga-21 to 1Rga-24). Fig. 18 is a perspective view for explaining modified forms of the second to fourth magnets in the electromagnetic ultrasonic probes of the eighth to tenth embodiments. Fig. 18A shows modified second and third magnets in the electromagnetic ultrasonic probe of the eighth embodiment, Fig. 18B shows modified fourth magnet in the electromagnetic ultrasonic probe of the ninth embodiment, and Fig. 18C shows modified fourth magnet in the electromagnetic ultrasonic probe of the tenth embodiment.

[0164] For example, in the electromagnetic ultrasonic probe TRg (REg) of the seventh embodiment, in a modified form of the system Sga of this electromagnetic ultrasonic probe, the second magnet 1Tg-2 (1Rg-2) is replaced with a second magnet 1Tga-2 (1Rga-2) of a modified form shown in Fig. 17. In the example shown in Fig. 17, the second magnet 1Tga-2 (1Rga-2) of this modified form includes four first to fourth segment magnets 1Tga-21 to 1Tga-24 (1Rga-21 to 1Rga-24) that are arranged sequentially in the circumferential direction to form a ring shape.

[0165] Similarly, in each of the electromagnetic ultrasonic probes TRh to TRj (REh to REj) of the eighth to tenth embodiments, the second to fourth magnets can be formed of a plurality of segment magnets, as shown in FIGS. 18A to 18C, respectively.

[0166] In the examples shown in FIGS. 17 and 18, there are four segment magnets, but the number may be any number, for example, two, three, or five or more.

[0167] Next, another embodiment will be described. (Eleventh embodiment) The eleventh embodiment is an embodiment of an ultrasonic flaw detector equipped with an electromagnetic ultrasonic probe system S of any of the electromagnetic ultrasonic probe systems Sa to Sj in the first to tenth embodiments described above.

[0168] Fig. 19 is a block diagram showing the configuration of an ultrasonic flaw detector in the 11th embodiment. The ultrasonic flaw detector D in the 11th embodiment includes, for example, an electromagnetic ultrasonic probe system S, a control processing unit 11, an input unit 12, an output unit 13, an interface unit (IF unit) 14, and a storage unit 15, as shown in Fig. 19.

[0169] The electromagnetic ultrasonic probe system S is any one of the electromagnetic ultrasonic probe systems Sa to Sj in the first to tenth embodiments described above, and includes a transmitting electromagnetic ultrasonic probe TR which is any one of the electromagnetic ultrasonic probes TRa to TRj used for transmission in the electromagnetic ultrasonic probe systems Sa to Sj in the first to tenth embodiments described above, and a receiving electromagnetic ultrasonic probe RE which is any one of the electromagnetic ultrasonic probes REa to REj used for reception in the electromagnetic ultrasonic probe systems Sa to Sj in the first to tenth embodiments described above. The transmitting electromagnetic ultrasonic probe TR is connected to a control processing unit 11, and generates ultrasonic waves as guided waves in an object Ob under the control of the control processing unit 11. The receiving electromagnetic ultrasonic probe RE is connected to the control processing unit 11, and receives ultrasonic waves from the object Ob under the control of the control processing unit 11, and outputs an electrical signal corresponding to the received ultrasonic waves to the control processing unit 11.

[0170] The input unit 12 is connected to the control processing unit 11 and is a device that inputs various commands, such as a command to start flaw detection, and various data necessary for operating the ultrasonic flaw detection device D, such as the name of the object Ob, to the ultrasonic flaw detection device D, and is, for example, a keyboard, a mouse, and a plurality of input switches to which predetermined functions are assigned. The output unit 13 is connected to the control processing unit 11 and is a device that outputs, under the control of the control processing unit 11, the commands and data input from the input unit 12 and the flaw detection results obtained by the ultrasonic flaw detection device D, and is, for example, a display device such as a CRT display, an LCD (liquid crystal display), or an organic EL display, or a printing device such as a printer.

[0171] The IF unit 14 is connected to the control processing unit 11 and is a circuit that inputs and outputs data to and from, for example, an external device under the control of the control processing unit 11, and is, for example, an interface circuit for RS-232C, which is a serial communication method, an interface circuit using the Bluetooth (registered trademark) standard, an interface circuit using the USB standard, etc. The IF unit 14 may also be, for example, a communication interface circuit that transmits and receives communication signals to and from an external device, such as a data communication card or a communication interface circuit conforming to the IEEE802.11 standard, etc.

[0172] The storage unit 15 is connected to the control processing unit 11 and is a circuit that stores various predetermined programs and various predetermined data under the control of the control processing unit 11. The various predetermined programs include, for example, a control processing program, which controls the various components S (TR, RE) 12-15 of the ultrasonic flaw detection device D, a transmission processing program that controls the transmitting electromagnetic ultrasonic probe TR so as to generate ultrasonic waves as guided waves in the object Ob by known conventional means, and a reception processing program that determines the flaw detection results of the object Ob based on electrical signals output from and input to the receiving electromagnetic ultrasonic probe RE by known conventional means. The various predetermined data include data required to execute these programs. The storage unit 15 includes, for example, a nonvolatile memory element such as a read-only memory (ROM) or a rewritable nonvolatile memory element such as an electrically erasable programmable read-only memory (EEPROM). The storage unit 15 includes a RAM (Random Access Memory) that stores data generated during execution of the predetermined program and serves as a so-called working memory of the control processing unit 11. The storage unit 15 may also be configured to include a hard disk device or a solid state drive (SSD) with a relatively large storage capacity.

[0173] The control processing unit 11 is a circuit for controlling each unit S (TR, RE), 12 to 15 of the ultrasonic flaw detection device D in accordance with the function of each unit, and for ultrasonic flaw detection of the object Ob. The control processing unit 11 is configured to include, for example, a CPU (Central Processing Unit) and its peripheral circuits. By executing a control processing program, the control processing unit 11 is functionally provided with a control unit 111, a transmission processing unit 112, and a reception processing unit 113.

[0174] The control unit 111 controls each of the units S (TR, RE), 12 to 15 of the ultrasonic flaw detector D in accordance with the function of each unit, and is in charge of overall control of the ultrasonic flaw detector D.

[0175] The transmission processing unit 112 controls the electromagnetic ultrasonic probe TR for transmission so as to generate ultrasonic waves as guided waves in the object Ob by a known conventional means.

[0176] The reception processing unit 113 obtains the flaw detection result of the object Ob based on the electrical signal output from the receiving electromagnetic ultrasonic probe RE and input by a known conventional means. The reception processing unit 113 outputs the obtained flaw detection result of the object Ob to the output unit 13.

[0177] In such an ultrasonic flaw detection device D, first, the object Ob is set in the electromagnetic ultrasonic probe system S, and a command to start flaw detection is input from the input unit 12. Upon receiving the command to start flaw detection, the ultrasonic flaw detection device D controls the transmitting electromagnetic ultrasonic probe TR by the transmission processing unit 112 of the control processing unit 11 to generate ultrasonic waves as guided waves in the object Ob. These ultrasonic waves propagate through the object Ob and are received by the receiving electromagnetic ultrasonic probe RE. The receiving electromagnetic ultrasonic probe RE receives the ultrasonic waves from the object Ob and outputs an electrical signal corresponding to the received ultrasonic waves to the control processing unit 11. The ultrasonic flaw detection device D determines the flaw detection result of the object Ob by the reception processing unit 113 of the control processing unit 11 based on the electrical signal output from the receiving electromagnetic ultrasonic probe RE and input, and outputs the determined flaw detection result of the object Ob to the output unit 13.

[0178] According to the eleventh embodiment, it is possible to provide an ultrasonic flaw detector D equipped with an electromagnetic ultrasonic probe system S. This ultrasonic flaw detector D is equipped with the electromagnetic ultrasonic probe system S, and therefore can form a more appropriate static magnetic field around the object Ob. In particular, when the ultrasonic flaw detector D is equipped with the electromagnetic ultrasonic probe system Sf in the sixth embodiment that can transmit and receive ultrasonic waves in a specific mode at a specific velocity, it is only necessary to analyze the ultrasonic waves in this specific mode at a specific velocity, and therefore the analysis can be simplified.

[0179] The ultrasonic flaw detector D is an electromagnetic ultrasonic detector, so it can be applied to high temperature environments. The ultrasonic flaw detector D uses a ring-shaped first magnet and coil, so it can be applied to wires and pipes with relatively small diameters.

[0180] In order to express the present invention, the present invention has been properly and sufficiently described above through the embodiments with reference to the drawings, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims. [Explanation of symbols]

[0181] Ob object Sa~Sj Electromagnetic Acoustic Probe System TRa to TRj Transmitting electromagnetic ultrasonic transducers REa to REj receiving electromagnetic ultrasonic transducer 1Ta~1Tf, 1Tg-1, 1Th-2, 1Ti-1, 1Ti-3, 1Tj-1, 1Tj-3, 1Tj-5, Ra~1Rf, 1Rg-1, 1Rh-2, 1Ri-1, 1Rj-1, 1Rj-3, 1Rj-5 First magnet 1Tg-2, 1Th-3, 1Rg-2, 1Rh-3 Second magnet 1Th-1, 1Rh-1 Third magnet 1Ti-2, 1Tj-2, 1Tj-4, 1Ri-2, 1Rj-2, 1Rj-4 4th magnet 1Tga-21~1Tga-24, 1Rga-21~1Rga-24 segment magnets 2Ta~2Tf, 2Ra~2Rf coils

Claims

1. a ring-shaped first magnet that is magnetized in the axial direction; a coil in which a long conductor member is wound in one direction, When a subject is placed inside the first magnet and inside the coil, the coil is placed at a position closer to the subject in the radial direction than the first magnet. Electromagnetic ultrasound probe.

2. the first magnets are a plurality of magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles; the coil is one and is arranged inside any one of the plurality of first magnets in the axial direction; The electromagnetic ultrasonic probe according to claim 1 .

3. The coil is disposed inside a first magnet that is centrally located in the axial direction. The electromagnetic ultrasonic probe according to claim 2 .

4. the first magnets are a plurality of magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles; The coil is one and is disposed in an axially adjacent portion between two adjacent first magnets of the plurality of first magnets. The electromagnetic ultrasonic probe according to claim 1 .

5. the first magnets are a plurality of magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles; a plurality of coils are provided, and the plurality of coils are respectively arranged inside a plurality of adjacent portions of two adjacent first magnets in the plurality of first magnets in the axial direction; The electromagnetic ultrasonic probe according to claim 1 .

6. The first magnet may be one or a plurality of first magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles, The coil is disposed inside one of the first magnets, or inside any one of the plurality of first magnets, and is a plurality of coils arranged side by side in the axial direction so that the directions of current flow alternate. The electromagnetic ultrasonic probe according to claim 1 .

7. the first magnets are a plurality of magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles; a plurality of coils are provided, and the plurality of coils are respectively arranged inside a plurality of the first magnets in the axial direction; The electromagnetic ultrasonic probe according to claim 1 .

8. the first magnets are a plurality of magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles; The coils are arranged in a plurality of adjacent portions of two adjacent first magnets in the axial direction. The electromagnetic ultrasonic probe according to claim 1 .

9. Further provided is a ring-shaped second magnet magnetized in the radial direction, the second magnet is juxtaposed in the axial direction on the one end face side of the first magnet so that the magnetic pole of the one end face of the first magnet in the axial direction and the magnetic pole of the inner circumferential surface of the second magnet are the same polarity, The coil may be one coil arranged inside the first magnet, or a plurality of coils arranged inside the first magnet and juxtaposed in the axial direction so that the directions of current flow alternate. The electromagnetic ultrasonic probe according to claim 1 .

10. Further provided are second and third ring-shaped magnets magnetized in the radial direction, the second magnet is juxtaposed in the axial direction on the one end face side of the first magnet so that the magnetic pole of the one end face of the first magnet in the axial direction and the magnetic pole of the inner circumferential surface of the second magnet are the same polarity, the third magnet is juxtaposed in the axial direction on the other end surface side of the first magnet so that the magnetic pole of the other end surface of the first magnet in the axial direction and the magnetic pole of the inner circumferential surface of the third magnet are the same polarity, The coil may be one coil arranged inside the first magnet, or a plurality of coils arranged inside the first magnet and juxtaposed in the axial direction so that the directions of current flow alternate. The electromagnetic ultrasonic probe according to claim 1 .

11. Further provided is a fourth magnet having a ring shape and magnetized in the radial direction, the first magnets are a plurality of magnets arranged side by side in the axial direction such that two adjacent first magnets face each other with the same poles; The fourth magnet is arranged radially adjacent to the outer circumferential side of the two first magnets facing with the same poles so that the poles of the same poles and the magnetic poles of the inner circumferential surfaces of the fourth magnets are the same poles, The coil may be one coil arranged inside the first magnet, or a plurality of coils arranged inside the first magnet and juxtaposed in the axial direction so that the directions of current flow alternate. The electromagnetic ultrasonic probe according to claim 1 .

12. The second magnet is formed of a plurality of segment magnets that are sequentially arranged in a circumferential direction to form a ring shape. The electromagnetic ultrasonic probe according to claim 9.

13. The second and third magnets are each formed of a plurality of segment magnets arranged sequentially in the circumferential direction to form a ring shape. The electromagnetic ultrasonic probe according to claim 10.

14. The fourth magnet is formed of a plurality of segment magnets that are sequentially arranged in a circumferential direction to form a ring shape. The electromagnetic ultrasonic probe according to claim 11.

15. The electromagnetic ultrasonic probe according to any one of claims 1 to 14, which is used for transmission; and the electromagnetic ultrasonic probe according to any one of claims 1 to 14, which is used for reception. Electromagnetic ultrasonic transducer system.

16. An ultrasonic flaw detection device comprising the electromagnetic ultrasonic probe system according to claim 15.

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