JP4327745B2 - Eddy current flaw detection probe and eddy current flaw detection device - Google Patents

Description

  The present invention relates to an eddy current flaw detection probe and an eddy current flaw detection device, and more particularly to an eddy current flaw detection probe and an eddy current flaw detection device suitable for performing flaw detection by superimposing eddy currents generated on an object to be inspected.

  An eddy current flaw detection probe that performs flaw detection by superimposing eddy currents generated on an object to be inspected has already been proposed as described in Patent Document 1, for example.

JP 2003-270214 A

  The eddy current flaw detection probe disclosed in Patent Document 1 is suitable for flaw detection at a deep position because the eddy current generated in the inspection object is superimposed. However, for example, when the direction of the superimposed eddy current coincides with the crack direction in the body to be inspected, there is a problem that a large change does not appear in the superimposed eddy current and accurate flaw detection cannot be performed.

  In order to solve such a problem, the eddy current flaw detection probe is moved in one direction on the object to be inspected, and then the eddy current flaw detection probe is moved so as to be orthogonal to the moving direction to detect flaws again. By doing this, we are trying to detect cracks in all directions. However, the eddy current flaw detection probe must be moved with respect to the object to be inspected at least twice so that the movement directions are orthogonal, and there is a problem that the flaw detection operation takes a long time.

  An object of the present invention is to provide an eddy current flaw detection probe and an eddy current flaw detection device that can perform flaw detection quickly regardless of the direction of occurrence of flaws on an object to be inspected.

  In order to achieve the above-mentioned object, the present invention provides a first excitation coil set having a plurality of excitation coils for generating an eddy current flaw probe by superimposing eddy currents on an object to be inspected, and a superimposed eddy by the first excitation coil set. A second excitation coil set having a plurality of excitation coils that are generated by superimposing eddy currents on the object to be inspected in a direction crossing the current generation direction, and an excitation coil of the first excitation coil set and the second excitation coil set; The present invention is characterized by comprising an eddy current detection coil for detecting a superimposed eddy current to be generated and a substrate on which a plurality of these excitation coils and eddy current detection coils are arranged and fixed in one direction.

  Furthermore, the eddy current flaw detector is arranged in a direction crossing the first exciting coil set having a plurality of exciting coils that are generated by superimposing eddy currents on the object to be inspected, and the direction in which the superimposed eddy current is generated by the first exciting coil set. A second excitation coil set having a plurality of excitation coils generated by superimposing eddy currents on the object to be inspected, and an eddy for detecting superimposed eddy currents generated by the excitation coils of the first excitation coil group and the second excitation coil group An eddy current flaw detection probe having a current detection coil, and a substrate on which a plurality of the excitation coils and eddy current detection coils are arranged and fixed in one direction, and switching for sequentially switching the plurality of excitation coils and the eddy current detection coils And a control unit having switching instruction means for instructing the switching means and a recording means for recording the detection signals of the eddy current detection coils that are sequentially switched. And wherein the door.

  As described above, by switching the excitation coils of the first excitation coil group and the second excitation coil group and exciting them, it becomes possible to cross the eddy currents in which flaws in all directions are superimposed. Since the flaw detection can be performed accurately only by moving the eddy current flaw detection probe in the direction, a quick flaw detection can be performed.

  As described above, according to the present invention, it is possible to obtain an eddy current flaw detection probe and an eddy current flaw detection device that can perform flaw detection quickly regardless of the direction of occurrence of flaws on the object to be inspected.

  A first embodiment of an eddy current flaw detection probe and an eddy current flaw detection apparatus using the same according to the present invention will be described below with reference to FIGS.

  The eddy current flaw detection probe 2 for flaw detection on the inspected object 1 includes a first exciting coil set (4A to 4D, 5A to 5D) that generates an eddy current so as to be superimposed on the inspected object 1, and a first A second excitation coil set (6A to 6E) for generating a superimposed eddy current on the object to be inspected in a direction crossing a generation direction of the superimposed eddy current generated by one excitation coil set, a first excitation coil set, and a second excitation coil set; Eddy current detection coils 7A to 7D for detecting superimposed eddy currents generated by the eddy current, and a plurality of first excitation coil sets, second excitation coil sets, and eddy current detection coils arranged in one direction and fixed, for example, from a polyimide film And a thin plate substrate 3. The thin plate substrate 3 is flexible so as to follow the surface shape of the object 1 to be inspected, and actually, the thin plate substrate 3 includes the first exciting coil group and the second exciting coil group. Wiring for supplying an exciting current is connected, and further, wiring for outputting a detection signal is connected to the eddy current detection coils 7A to 7D, but they are omitted here.

  The first excitation coil groups (4A to 4D, 5A to 5D) are arranged so as to sandwich each eddy current detection coil with respect to a plurality of eddy current detection coils 7A to 7D arranged at intervals in one direction of the substrate 3. The two excitation coils 4A to 4D and the excitation coils 5A to 5D are opposed to each other and are arranged in parallel with the arrangement direction of the eddy current detection coils 7A to 7D. The exciting coils 4A to 4D and the exciting coils 5A to 5D facing each other across the eddy current detection coils 7A to 7D are wound in opposite directions so that the eddy current generation directions are overlapped with each other. In the figure, it is indicated by “+” and “−”.

  In the second exciting coil groups (6A to 6E), the exciting coils 6A to 6E are arranged with the eddy current detecting coils 7A to 7D so as to sandwich the eddy current detecting coils with respect to the eddy current detecting coils 7A to 7D. Arranged in the direction. The exciting coils 6A to 6E facing each other across the eddy current detection coils 7A to 7D are also wound in opposite directions so that the generation directions of the eddy currents overlap with each other. “-”.

  Excitation of each coil of the eddy current probe 2 configured as described above and detection of eddy current are performed by the control unit 8 shown in FIG.

  The control unit 8 has switching means 9 for sequentially switching the connections of the excitation coils 4A to 4D, 5A to 5D, 6A to 6E, and the eddy current detection coils 7A to 7D. The switching means 9 includes a first multiplexer 10A for sequentially switching the connections of the excitation coils 4A to 4D and 5A to 5D of the first excitation coil set and a second multiplexer for sequentially switching the connections of the excitation coils 6A to 6E of the second excitation coil set. A multiplexer 10B and a third multiplexer 10C for sequentially switching the connection of the eddy current detection coils 7A to 7D are provided. The first to third multiplexers 10A to 10C are connected to a computer 11 that gives an instruction to switch the coils 4A to 4D, 5A to 5D, 6A to 6E, and 7A to 7D according to the input program. The coils 4A to 4D, 5A to 5D, and 6A to 6E connected to the first multiplexer 10A and the second multiplexer 10B are excited from the computer 11 through the transmission circuit 12 and the amplifier 13 in synchronization with the switching order. A signal is input. On the other hand, signals detected from the coils 7A to 7D are output from the third multiplexer 10C in synchronization with the switching order, and the output signals are supplied to the A / D converter 16 via the amplifier 14 and the phase detector 15. The input and A / D converted signal is stored in the memory 17 as data. The accumulated data is displayed on the display device 18 by operating the computer 11, and the display can be displayed at the same time as the flaw detection work or after the flaw detection work.

  Here, in the eddy current flaw detector having the above-described configuration, the computer 11 corresponds to switching instruction means for instructing the switching order in the present invention to the switching order of the first excitation coil group, the second excitation coil group, and the eddy current detection coil. The memory 17 corresponds to recording means for recording the detection signals of the eddy current detection coils sequentially switched, and the first multiplexer 10A, the second multiplexer 10B, and the third multiplexer 10C are the first in the present invention. The display device 18 corresponds to a display means for displaying a signal based on the detection signal of the eddy current detection coil.

  Next, an example where flaw detection is performed on the inspection object 1 using the eddy current flaw detection apparatus having the above configuration will be described.

  First, as shown in FIG. 1, the eddy current flaw detection probe 2 is pressed on the object 1 so that there is no gap or the gap is constant. And the flaw detection of the range of the width W shown with the broken line of to-be-inspected object 1 shall be performed.

  Thereafter, as shown in FIG. 3, according to the program input to the computer 11, two exciting coils 6A to 6E of the second exciting coil set of the eddy current flaw detection probe 2 are excited by the second multiplexer 10B. Switch sequentially.

  That is, at the first time t1, the exciting coils 6A and 6B are excited to generate an eddy current superimposed in the inspection object 1. The superimposed eddy current is detected by the eddy current detection coil 7A. Therefore, at time t1, the sensor element P1 is configured by the excitation coils 6A and 6B and the eddy current detection coil 7A indicated by diagonal lines.

  Thereafter, at time t2, the exciting coils 6B and 6C are excited, and the sensor element P2 for detecting a change in eddy current is formed by the eddy current detecting coil 7B. Thereafter, the excitation is sequentially switched, and at time t3, the sensor element P3, At time t4, flaw detection is performed by the sensor element P4.

  In the process of this flaw detection, as shown in FIG. 5, if there is a crack or the like in the inspection object 1 in the direction crossing the superimposed eddy current I, the flow of the eddy current I changes. The presence of a crack can be detected by detecting the change with any of the eddy current detection coils 7A to 7D. However, if there is a crack along the direction of the superimposed eddy current I, the flow of the eddy current I is hardly changed, so the presence of the crack cannot be detected.

  Therefore, according to the program input to the computer 11, after the flaw detection is completed in the exciting coils 6A to 6E and the eddy current detecting coils 7A to 7D of the second exciting coil set, the function of the second multiplexer 10B is stopped. The first multiplexer 10A is caused to function. Among the exciting coils 4A to 4D and 5A to 5D of the first exciting coil group, two opposing ones are sequentially excited as shown in FIG. By doing so, the eddy current I in the direction crossing the direction of the eddy current I superimposed by the excitation coils 6A to 6E of the second excitation coil set is converted into the excitation coils 4A to 4D and 5A to 5D of the first excitation coil set. Can be superimposed.

  Specifically, at time t5, the exciting coils 4A and 5A are excited to generate an eddy current superimposed in the device under test 1. The superimposed eddy current is detected by the eddy current detection coil 7A. Therefore, at time t5, the sensor element P5 is configured by the excitation coils 4A and 5A and the eddy current detection coil 7A indicated by oblique lines.

  Thereafter, at time t6, the exciting coils 4B and 5B are excited, and the sensor element P6 for detecting a change in eddy current is formed by the eddy current detecting coil 7B. Thereafter, the excitation is sequentially switched, and at time t7, the sensor element P7, At time t8, flaw detection is performed by the sensor element P8.

  In the process of this flaw detection, as shown in FIG. 5, if there is a crack or the like in the inspection object 1 in the direction crossing the superimposed eddy current I, the flow of the eddy current I changes. The presence of a crack can be detected by detecting the change with any of the eddy current detection coils 7A to 7D.

  The detection signals from the eddy current detection coils 7 </ b> A to 7 </ b> D are recorded as data in the memory 17 in correspondence with each sensor element position of the eddy current flaw detection probe 2, thereby displaying the flaw detection position on the display device 18. be able to. The display by the display device 18 may be displayed in synchronization with the flaw detection work or may be displayed at the time of verification after the completion of the flaw detection work.

  Table 1 summarizes the relationship between the sensor elements P1 to P8 and the coils at the times t1 to t8 described above.

  After the flaw detection with the exciting coils 4A to 4D, 5A to 5D, 6A to 6E and the eddy current detection coils 7A to 7D as described above is completed, the eddy current flaw detection probe 2 is moved in the direction of the arrow in FIG. Again, as shown in FIGS. 3 and 4, the next flaw detection is performed by switching the excitation of each coil.

  By the way, in the above description, after the flaw detection is completed in the excitation coils 6A to 6E and the eddy current detection coils 7A to 7D of the second excitation coil group, the excitation coils 4A to 4D and 5A to 5D of the first excitation coil group are described. And eddy current detection coils 7 </ b> A to 7 </ b> D are subjected to flaw detection so that flaws in all directions can be detected. However, for example, as shown in FIG. 6, the excitation coils 6A to 6E of the second excitation coil group and the excitation coils 4A to 4D and 5A to 5D of the first excitation coil group are alternately switched and excited to perform flaw detection. You may do it.

  That is, at time T1, the excitation coils 6A and 6B of the second excitation coil set are excited to form a sensor element Pa with the eddy current detection coil 7A, and the flaw detection is performed. The excitation element 4A, 5A and the eddy current detection coil 7A form the sensor element Pb. At time T3, the excitation coil 6B, 6C of the second excitation coil set and the eddy current detection coil 7B form the sensor element Pa. At time T8, the flaw detection can be performed by forming the sensor element Ph with the exciting coils 4D and 5D and the eddy current detecting coil 7D of the first exciting coil set. Table 2 summarizes the relationship between the sensor elements Pa to Ph and the coils at times T1 to T8.

  As described above, according to the present embodiment, a pair of excitation coils and eddy current detection coils are sequentially switched to generate superimposed eddy currents in a crossing direction, thereby quickly causing bidirectional scratches. Can be flawed.

  In the above description, in one eddy current flaw detection probe 2, the excitation coils 4A to 4D, 5A to 5D of the first excitation coil set, the eddy current detection coils 7A to 7D, and the excitation coils 6A to 6E of the second excitation coil set are described. And eddy current detection coils 7A to 7D are alternately switched to perform excitation and flaw detection. However, for example, when the width W of the inspection object 1 in FIG. 1 to be flawed is wide, naturally the eddy current flaw detection probe 2 becomes longer in accordance with the width W, and the number of coils increases. In such a state, when these coils are switched alternately from one end to the other end in order, it takes time for switching and flaw detection.

  In such a case, as shown in FIG. 7, the excitation coils 6A and 6B (or 4A and 4B) on one end side and the excitation coils 6E and 6F (or 4E and 5E) on the intermediate part are excited to detect eddy currents. The coils 7A and 7E are caused to function, and then the excitation coils 6B and 6C (or 4B and 5B) and the excitation coils 6F and 7G (or 4F and 5F) are excited to cause the eddy current detection coils 7B and 7F to function. Thus, by sequentially switching from the two locations in the same direction at the same time, the flaw detection time for traversing the flaw detection width W can be shortened to almost half.

  Further, the description so far has been made in one eddy current flaw detection probe 2 in which the excitation coils 4A to 4H, 5A to 5H of the first excitation coil set, the excitation coils 6A to 6I of the second excitation coil set, and the eddy current detection coil. 7A to 7H, the flaw detection time can be shortened also in the second embodiment of the eddy current flaw detector shown in FIG. 8, for example. In FIG. 8, the same reference numerals as those in FIG. 2 indicate the same parts, and thus detailed description thereof is omitted.

  The eddy current flaw detector shown in FIG. 8 differs from the eddy current flaw detector shown in FIG. 2 in that a first eddy current flaw probe 2A and a second eddy current flaw probe 2B are provided.

  That is, the first eddy current flaw detection probe 2A includes a first exciting coil group (4A to 4D, 5A to 5D) that generates eddy currents so as to be superimposed, and eddy current detection coils 7A to 7D that detect the superimposed eddy currents. The second eddy current flaw detection probe 2B is provided with a second excitation coil set (6A to 6E) that generates a superimposed eddy current on the object to be inspected in a direction that intersects the direction in which the superimposed eddy current is generated by the first excitation coil set. ) And eddy current detection coils 20A to 20D for detecting the superimposed eddy current.

  The first eddy current flaw detection probe 2A and the second eddy current flaw detection probe 2B are arranged at an interval at which the superimposed eddy currents do not interfere with each other. By sequentially switching between the second multiplexer 10B and the third multiplexer 10C, the eddy current is detected at the same time.

  Thus, by preparing two sets of eddy current flaw detection probes, the number of coils to be used increases, but the flaw detection time can be shortened to almost half.

  In each of the embodiments described above, a large number of exciting coils 4A to 4H, 5A to 5H, 6A to 6I and a large number of eddy current detection coils 7A to 7H, 20A to 20H are used as eddy current flaw detection probes. Is a first excitation coil set consisting of two excitation coils and a second excitation consisting of two excitation coils that are generated so as to superimpose eddy currents in a direction crossing the direction of generation of superimposed eddy currents generated by the first excitation coil set An eddy current flaw detection probe is configured by fixing a coil set and one eddy current detection coil for detecting superimposed eddy current generated by the excitation coils of the first excitation coil set and the second excitation coil set to the substrate. In this case, an eddy current flaw detection probe and an eddy current flaw detection device that can perform flaw detection quickly regardless of the direction in which the flaws are generated can be obtained.

The perspective view which shows one Embodiment of the eddy current test probe by this invention. 1 is a block diagram showing a first embodiment of an eddy current flaw detector according to the present invention. The 1st pattern which shows the switching state of the exciting coil by the eddy current flaw detector of this invention. The 2nd pattern which shows the switching state of the exciting coil by the eddy current flaw detector of this invention. Explanatory drawing which shows the superimposed eddy current. The 3rd pattern which shows the switching state of the exciting coil by the eddy current flaw detector of this invention. The 4th pattern which shows the switching state of the exciting coil by the eddy current flaw detector of this invention. The block diagram which shows 2nd Embodiment of the eddy current flaw detector by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Test object, 2 ... Eddy current test probe, 3 ... Board | substrate, 4A-4D, 5A-5D, 6A-6E ... Excitation coil, 7A-7H, 20A-20H ... Eddy current detection coil, 8 ... Control part, DESCRIPTION OF SYMBOLS 9 ... Switching means, 10A-10C ... 1st-3rd multiplexer, 11 ... Computer, 17 ... Memory, 18 ... Display apparatus.

Claims (5)

An eddy current is applied to the object to be inspected in a direction intersecting the direction of generation of the superimposed eddy current generated by the first excitation coil set and the first exciting coil group that is generated to superimpose the eddy current on the object to be inspected. A second excitation coil set composed of two excitation coils generated so as to be superimposed, and one eddy current detection coil for detecting a superimposed eddy current generated by the excitation coils of the first excitation coil set and the second excitation coil set; The first exciting coil set and the second exciting coil set are arranged such that two exciting coils are opposed to each other across one eddy current detecting coil, and the first exciting coil set is The opposing direction of the two exciting coils and the opposing direction of the two exciting coils of the second exciting coil set are orthogonal to each other centering on the eddy current detection coil, and the first exciting coil set and the second exciting coil set are The excitation co Coil probe, characterized in that a substrate fixed Le and with said eddy current detection coil. A first exciting coil set comprising a plurality of exciting coils that are generated so as to superimpose eddy currents on the object to be inspected, and eddy currents are applied to the object to be examined in a direction that intersects the direction of generation of the superimposed eddy currents by the first exciting coil group. comprising a second exciting coil pair consisting of a plurality of exciting coils for generating so as to overlap, and eddy current detection coil excitation coil of the first exciting coil pair and the second exciting coil pair detects superimposed eddy current generated The first excitation coil set and the second excitation coil set are arranged such that two excitation coils are opposed to each other across one eddy current detection coil, and two of the first excitation coil sets are arranged. The opposing direction of the exciting coil and the opposing direction of the two exciting coils of the second exciting coil set are orthogonal to each other with the eddy current detection coil as the center, and the excitation of the first exciting coil set and the second exciting coil set is the same. Coil and Coil probe, characterized in that a substrate which is fixed by arranging a plurality of the Kiuzu current detection coil in one direction. An eddy current is applied to the object to be inspected in a direction intersecting the direction of generation of the superimposed eddy current generated by the first excitation coil set and the first exciting coil group that is generated to superimpose the eddy current on the object to be inspected. A second excitation coil set composed of two excitation coils generated so as to be superimposed, and one eddy current detection coil for detecting a superimposed eddy current generated by the excitation coils of the first excitation coil set and the second excitation coil set; wherein the the first exciting coil pair and said second exciting coils pair, two excitation coils across the respective one of the eddy current detection coil and is placed facing and sets of the first excitation coil The opposing direction of the two exciting coils and the opposing direction of the two exciting coils of the second exciting coil set are orthogonal to each other centering on the eddy current detection coil, and the first exciting coil set and the second exciting coil set are The excitation co And an eddy current flaw detection probe having a substrate on which the eddy current detection coil is fixed, switching means for sequentially switching the excitation coil and the eddy current detection coil, and switching instruction means for instructing the switching order to the switching means And an eddy current flaw detector comprising: a recording unit that records the detection signals of the eddy current detection coils that are sequentially switched . A first exciting coil set comprising a plurality of exciting coils that are generated so as to superimpose eddy currents on the object to be inspected, and eddy currents are applied to the object to be examined in a direction that intersects the direction of generation of the superimposed eddy currents by the first exciting coil group. comprising a second exciting coil pair consisting of a plurality of exciting coils for generating so as to overlap, and eddy current detection coil excitation coil of the first exciting coil pair and the second exciting coil pair detects superimposed eddy current generated The first excitation coil set and the second excitation coil set are arranged such that two excitation coils are opposed to each other across one eddy current detection coil, and two of the first excitation coil sets are arranged. The opposing direction of the exciting coil and the opposing direction of the two exciting coils of the second exciting coil set are orthogonal to each other with the eddy current detection coil as the center, and the excitation of the first exciting coil set and the second exciting coil set is the same. Coil and And the eddy current flaw detection probe having a substrate and a Kiuzu current detection coil is fixed by a plurality arranged in one direction, and sequentially switching the switching means and a plurality of said exciting coil and said eddy current detection coil, switching on the switching means An eddy current flaw detector comprising: a switching instructing unit for instructing the order; and a control unit having recording means for recording the detection signals of the eddy current detecting coils that are sequentially switched. The switching means includes first switching means for sequentially switching a plurality of excitation coils of the first excitation coil set, second switching means for sequentially switching a plurality of excitation coils of the second excitation coil set, and a plurality of the switching means And a third switching means for sequentially switching eddy current detection coils, and the control section is provided with display means for displaying a signal based on a detection signal of the eddy current detection coil. Item 5. The eddy current flaw detector according to item 3 or 4 .

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