JP2014059258A - Multi yoke magnetizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetizer capable of forming a rotating magnetic field in a wide range with a high uniformity with a small unevenness in rotating magnetic flux density on the surface of an object to be inspected.SOLUTION: The multi yoke magnetizer includes first-sixth magnetic poles 11-16 each including a yoke wound with winding, which are disposed being separated having a phase difference of 60 degrees from each other. The first magnetic pole 11, the third magnetic pole 13 and the fifth magnetic pole 15 have winding ends connected to each other at a neutral point with a Y connection. The second magnetic pole 12, the fourth magnetic pole 14 and the sixth magnetic pole 16 have winding starts connected to each other at neutral point with a Y connection. The winding start of a coil L11 of the first magnetic pole 11 is connected to the winding end of a coil L14 of the fourth magnetic pole 14. The winding start of a coil L13 of the third magnetic pole 13 is connected to the winding end of a coil L16 of the sixth magnetic pole 16. The winding start of a coil L15 of the fifth magnetic pole 15 is connected to the winding end of a coil L12 of the second magnetic pole 12.

Description

  The present invention relates to a magnetizer used for magnetic particle flaw detection and the like.

  As an example of a non-destructive inspection method, a test object is magnetized with a magnetizing device, magnetic powder is dispersed on the magnetized test object, and the damage or cracking of the test object is determined from the distribution state of the magnetic powder adhered to the test object. There are known magnetic particle flaw detection methods for detecting. When magnetizing an object to be inspected with a magnetizing apparatus in such a magnetic particle flaw detection method, the accuracy of detection of the scratch or crack is determined by the angle between the direction of the scratch or crack generated in the object to be inspected and the direction of the magnetic field lines of the magnetic field. Come different. Specifically, in the state where the lines of magnetic force are orthogonal to the scratches and cracks, the leakage magnetic flux generated by the scratches and cracks is the largest, so the magnetic powder pattern formed by the magnetic particles attached to the scratches and cracks is most clearly identified. be able to.

  However, it is usually difficult to predict the direction of scratches and cracks occurring in the object to be inspected. Therefore, by magnetizing the object to be inspected using a magnetizing device that generates a multi-directional magnetic field, the object to be inspected is magnetized in a state in which the magnetic lines of force are perpendicular to the scratches and cracks regardless of the direction of the scratches or cracks. It has been conventionally performed to improve the detection accuracy of body scratches and cracks.

  As an example of a magnetizing apparatus that generates a multidirectional magnetic field, a three-pole yoke magnetizer in which three magnetizing elements are arranged with a phase difference of 120 degrees from each other is known. Further, applicants have proposed a split yoke magnetizer that employs a structure in which the three magnetizing elements of this three-pole yoke magnetizer are divided into two parts, and that can form a highly uniform rotating magnetic field over a wide range. Developed. The three-pole yoke-type magnetizer and the split yoke-type magnetizer can form a rotating magnetic field whose magnetic field direction changes by 360 degrees by applying a three-phase AC voltage to the first to third magnetizing elements ( For example, see Patent Document 1 and Non-Patent Document 1).

Japanese Examined Patent Publication No. 61-25312

Katsuhiro Fukuoka and five others, “Examination of yoke separation in rotating magnetic field type magnetic particle flaw detection magnetizer”, Japan Association for Nondestructive Inspection, June 29, 2012, NDI material 30344

  The split yoke type magnetizer developed by the applicants is an improvement over the conventional three-pole yoke type magnetizer in order to form a highly uniform rotating magnetic field over a wide range. However, in recent years, there has been a demand for a magnetizer capable of forming a rotating magnetic field with higher uniformity in a wider range, while further improvement in the accuracy of detection of scratches and cracks on the object to be inspected is desired.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a magnetizer capable of forming a rotating magnetic field with high uniformity with a small deviation of rotating magnetic flux density on the surface of the object to be inspected. is there.

<First Aspect of the Present Invention>
A first aspect of the present invention includes first to sixth magnetization elements that are sequentially arranged with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke, and the first magnetization element and the third magnetization element The element and the fifth magnetizing element are connected by a Y connection with the winding end of the electric wire connected to the neutral point, and the second magnetizing element, the fourth magnetizing element, and the sixth magnetizing element are The winding start is connected to the neutral point and connected by Y connection, the winding start of the wire of the first magnetization element and the winding end of the wire of the fourth magnetization element are connected, and the winding of the third magnetization element The winding start of the electric wire and the winding end of the electric wire of the sixth magnetization element are connected, and the winding start of the electric wire of the fifth magnetization element and the winding end of the electric wire of the second magnetization element are connected. It is a featured multi-yoke type magnetizer.

  The first to sixth magnetization elements are arranged in the order of the first magnetization element → the second magnetization element → the third magnetization element → the fourth magnetization element → the fifth magnetization element → the sixth magnetization element in the clockwise or counterclockwise direction. They are arranged at positions that are out of phase by 60 degrees. Then, for example, the connection point between the start of winding of the first magnetizing element and the end of winding of the fourth magnetizing element is connected to the U phase of the three-phase AC power source, and the start of winding of the third magnetizing element and the sixth The connection point between the winding end of the magnetic element and the winding end of the wire is connected to the V phase of the three-phase AC power source, and the connection point between the winding start of the fifth magnetization element and the winding end of the second magnetization element is connected to the three-phase alternating current. Connect to the W phase of the power supply and apply a three-phase AC voltage.

  Here, based on the phase of the AC voltage (U phase) applied to the first magnetization element, an AC voltage (V phase) whose phase is shifted by 120 degrees is applied to the third magnetization element, and the fifth magnetization element is applied to the fifth magnetization element. The AC voltage (W phase) having a phase shift of 240 degrees is applied. The second magnetization element, the fourth magnetization element, and the sixth magnetization element have the winding direction of the wire opposite to the first magnetization element, the third magnetization element, and the fifth magnetization element. Therefore, an AC voltage whose phase is shifted by 180 degrees from the U-phase AC voltage is applied to the fourth magnetization element. Similarly, an AC voltage whose phase is shifted 180 degrees from the V-phase AC voltage is applied to the sixth magnetization element, and an AC voltage whose phase is shifted 180 degrees from the W-phase AC voltage is applied to the second magnetization element. Will be. Therefore, based on the phase of the AC voltage (U phase) applied to the first magnetization element, an AC voltage having a phase shift of 180 degrees is applied to the fourth magnetization element, and the phase is 300 degrees to the sixth magnetization element. A shifted AC voltage is applied, and an AC voltage whose phase is shifted by 60 degrees is applied to the second magnetization element.

  In other words, the multi-yoke magnetizer according to the first aspect of the present invention applies a three-phase AC voltage, so that an AC voltage whose phase is shifted by 60 degrees with respect to the AC voltage applied to the first magnetization element is second. An AC voltage that is applied to the magnetizing element and is 120 degrees out of phase is applied to the third magnetizing element, an AC voltage that is 180 degrees out of phase is applied to the fourth magnetizing element, and an AC voltage that is 240 degrees out of phase is An AC voltage having a phase shift of 300 degrees is applied to the sixth magnetizing element.

  That is, in the multi-yoke magnetizer according to the first aspect of the present invention, an AC voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetization elements by applying a three-phase AC voltage. . As a result, the multi-yoke type magnetizer according to the first aspect of the present invention can form a rotating magnetic field with high uniformity with a small deviation in rotating magnetic flux density on the surface of the object to be inspected.

  As a result, according to the first aspect of the present invention, there is obtained an effect that it is possible to provide a magnetizer capable of forming a rotating magnetic field with high uniformity with a small deviation of rotating magnetic flux density on the surface of the object to be inspected. It is done.

<Second Aspect of the Present Invention>
A second aspect of the present invention includes first to sixth magnetization elements, which are sequentially arranged with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke, and the first magnetization element and the third magnetization element The element and the fifth magnetizing element are connected by a Y connection with the end of winding of the electric wire connected to a neutral point, and the winding start of the electric wire of the first magnetizing element and the electric wire start of the fourth magnetizing element Are connected, and the winding start of the third magnetization element and the winding start of the sixth magnetization element are connected, and the winding start of the fifth magnetization element and the winding of the second magnetization element The multi-yoke type magnetizer is characterized in that a winding start is connected.

  The first to sixth magnetization elements are arranged in the order of the first magnetization element → the second magnetization element → the third magnetization element → the fourth magnetization element → the fifth magnetization element → the sixth magnetization element in the clockwise or counterclockwise direction. They are arranged at positions that are out of phase by 60 degrees. And, for example, the end of winding of the wire of the fourth magnetizing element is connected to the U phase of the three-phase AC power source, the end of winding of the wire of the sixth magnetizing element is connected to the V phase of the three-phase AC power source, and A three-phase AC voltage is applied by connecting the end of winding of the wire to the W-phase of a three-phase AC power source.

  As a result, in the multi-yoke magnetizer according to the second aspect of the present invention, as in the first aspect of the present invention described above, an alternating voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetization elements. Will be. That is, similarly to the first aspect of the present invention described above, a highly uniform rotating magnetic field with a small deviation of the rotating magnetic flux density on the surface of the object to be inspected can be formed over a wide range.

  As a result, according to the second aspect of the present invention, there is obtained an effect that it is possible to provide a magnetizer capable of forming a rotating magnetic field having a high uniformity with a small deviation of the rotating magnetic flux density on the surface of the object to be inspected. It is done.

<Third Aspect of the Present Invention>
A third aspect of the present invention includes first to sixth magnetization elements, which are sequentially arranged with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke, and the first magnetization element and the third magnetization element The element and the fifth magnetization element are connected by Δ connection, and the second magnetization element, the fourth magnetization element, and the sixth magnetization element are connected by Δ connection, and the first magnetization element and The winding start of the electric wire of the sixth magnetization element and the winding end of the electric wire of the third magnetization element and the fourth magnetization element are connected, and the winding start of the electric wire of the second magnetization element and the third magnetization element The fifth magnetizing element and the end of winding of the electric wire of the sixth magnetizing element are connected, and the starting of winding of the electric wire of the fourth magnetizing element and the fifth magnetizing element and the electric wire of the first magnetizing element and the second magnetizing element Is connected to the winding end of This is a Lucy-Yoke type magnetizer.

  The first to sixth magnetization elements are arranged in the order of the first magnetization element → the second magnetization element → the third magnetization element → the fourth magnetization element → the fifth magnetization element → the sixth magnetization element in the clockwise or counterclockwise direction. They are arranged at positions that are out of phase by 60 degrees. And, for example, the connection point between the winding start of the first and sixth magnetization elements and the winding end of the third and fourth magnetization elements is connected to the U-phase of the three-phase AC power source, The connection point between the winding start of the magnetic elements and the third magnetic element and the winding ends of the fifth and sixth magnetic elements is connected to the V phase of the three-phase AC power source, and the fourth and fifth magnetic elements A connection point between the winding start of the electric wire of the magnetizing element and the winding end of the electric wire of the first magnetizing element and the second magnetizing element is connected to the W phase of the three-phase AC power source and a three-phase AC voltage is applied.

  As a result, in the multi-yoke magnetizer according to the third aspect of the present invention, as in the first aspect of the present invention described above, an alternating voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetization elements. Will be. That is, similarly to the first aspect of the present invention described above, a highly uniform rotating magnetic field with a small deviation of the rotating magnetic flux density on the surface of the object to be inspected can be formed over a wide range.

  As a result, according to the third aspect of the present invention, there is obtained an effect that it is possible to provide a magnetizer capable of forming a rotating magnetic field having a high uniformity with a small deviation of the rotating magnetic flux density on the surface of the object to be inspected. It is done.

<Fourth aspect of the present invention>
4th aspect of this invention is arrange | positioned in order with a 60 degree phase difference mutually, is equipped with the 1st-6th magnetization element by which an electric wire is wound around a yoke, The winding end of the electric wire of the said 1st magnetization element And the winding end of the electric wire of the fourth magnetization element are connected, and the winding end of the electric wire of the third magnetization element and the winding end of the electric wire of the sixth magnetization element are connected, and An end of winding and an end of winding of the electric wire of the second magnetization element are connected, and an initial winding of the electric wire of the first magnetization element and an initial winding of the electric wire of the sixth magnetization element are connected. The winding start of the electric wire and the winding start of the electric wire of the third magnetization element are connected, and the winding start of the electric wire of the fourth magnetization element and the winding start of the electric wire of the fifth magnetization element are connected. It is a featured multi-yoke type magnetizer.

  The first to sixth magnetization elements are arranged in the order of the first magnetization element → the second magnetization element → the third magnetization element → the fourth magnetization element → the fifth magnetization element → the sixth magnetization element in the clockwise or counterclockwise direction. They are arranged at positions that are out of phase by 60 degrees. And, for example, the connection point between the start of winding of the first magnetizing element and the start of winding of the sixth magnetizing element is connected to the U phase of the three-phase AC power source, and the start of winding of the second magnetizing element and the third The connection point between the winding start of the magnetic element and the wire winding of the three-phase AC power source is connected to the V phase of the three-phase AC power supply, and the connection point between the winding start of the fourth magnetization element and the winding start of the fifth magnetization element is the three-phase AC. Connect to the W phase of the power supply and apply a three-phase AC voltage.

  As a result, in the multi-yoke magnetizer according to the fourth aspect of the present invention, as in the first aspect of the present invention described above, an alternating voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetization elements. Will be. That is, similarly to the first aspect of the present invention described above, a highly uniform rotating magnetic field with a small deviation of the rotating magnetic flux density on the surface of the object to be inspected can be formed over a wide range.

  As a result, according to the fourth aspect of the present invention, there is obtained an effect that it is possible to provide a magnetizer capable of forming a highly uniform rotating magnetic field with a small deviation in rotating magnetic flux density on the surface of the object to be inspected. It is done.

<Fifth aspect of the present invention>
A fifth aspect of the present invention is the multi-yoke according to any one of the first to fourth aspects of the present invention described above, wherein the first to sixth magnetization elements are arranged concentrically. Type magnetizer.
According to such a feature, since the strength of the magnetic field in each direction of the rotating magnetic field can be made more uniform, the deviation of the rotating magnetic flux density on the surface of the object to be inspected can be further reduced.

  According to the present invention, it is possible to provide a magnetizer capable of forming a rotating magnetic field with high uniformity with a small deviation in rotating magnetic flux density on the surface of an object to be inspected over a wide range.

The top view of the multi yoke type magnetizer of the 1st example. The front view of the multi yoke type magnetizer of the 1st example. The schematic diagram of the internal magnetic circuit of the multi yoke type magnetizer in the 1st example. The connection diagram of the multi yoke type | mold magnetizer of 1st Example. The timing chart which illustrated the output voltage waveform of a three-phase alternating current power supply. The timing chart which illustrated the voltage waveform of each magnetic pole of a multi yoke type magnetizer. The Lissajous waveform diagram of the rotating magnetic flux density at the measurement point P1 on the surface of the inspection object. The Lissajous waveform diagram of the rotating magnetic flux density at the measurement point P2 on the surface of the inspection object. The Lissajous waveform diagram of the rotating magnetic flux density at the measurement point P3 on the surface of the object to be inspected. The connection diagram which illustrated the multi-yoke type | mold magnetizer of 2nd Example. The connection diagram which illustrated the multi yoke type | mold magnetizer of 3rd Example. The connection diagram which illustrated the multi yoke type | mold magnetizer of 4th Example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, this invention is not specifically limited to the Example demonstrated below, It cannot be overemphasized that a various deformation | transformation is possible within the range of the invention described in the claim.

<First Example of Multi-Yoke Magnetizer Configuration>
A first embodiment of the configuration of the multi-yoke magnetizer 10 according to the present invention will be described with reference to FIGS.
FIG. 1 is a plan view of a multi-yoke magnetizer 10 of the first embodiment. FIG. 2 is a front view of the multi-yoke magnetizer 10 of the first embodiment. FIG. 3 is a schematic diagram of the internal magnetic circuit of the multi-yoke magnetizer 10 in the first embodiment. FIG. 4 is a connection diagram of the multi-yoke magnetizer 10 of the first embodiment.

  The multi-yoke type magnetizer 10 of the first embodiment includes first to sixth magnetic poles 11 to 16, a multi-yoke 17, and three connection terminals T1 to T3.

  The first to sixth magnetic poles 11 to 16 as “magnetization elements” are sequentially arranged with a phase difference of 60 degrees from each other. That is, the first to sixth magnetic poles 11 to 16 are arranged in the clockwise direction in a plan view in the order of the first magnetic pole 11 → the second magnetic pole 12 → the third magnetic pole 13 → the fourth magnetic pole 14 → the fifth magnetic pole 15 → the sixth magnetic pole 16. They are arranged at positions that are out of phase by 60 degrees in the arrangement order.

More specifically, in the first to sixth magnetic poles 11 to 16, the third magnetic pole 13 is arranged with a phase difference of 120 degrees with respect to the first magnetic pole 11, and 120 to the first magnetic pole 11 and the third magnetic pole 13. The fifth magnetic pole 15 is arranged with a phase difference of degrees. The second magnetic pole 12 is disposed between the first magnetic pole 11 and the third magnetic pole 13 with a phase difference of 60 degrees with respect to the first magnetic pole 11 and the third magnetic pole 13. The fourth magnetic pole 14 is disposed between the third magnetic pole 13 and the fifth magnetic pole 15 with a phase difference of 60 degrees with respect to the third magnetic pole 13 and the fifth magnetic pole 15. The sixth magnetic pole 16 is disposed between the first magnetic pole 11 and the fifth magnetic pole 15 with a phase difference of 60 degrees with respect to the first magnetic pole 11 and the fifth magnetic pole 15.
Note that the first to sixth magnetic poles 11 to 16 may be arranged at positions shifted in phase by 60 degrees in the counterclockwise direction in the above-described arrangement order.

  The multi-yoke 17 is a yoke formed by laminating silicon steel plates, and has first to sixth yokes 171 to 176 and a back yoke 177. The first to sixth yokes 171 to 176 are formed to be orthogonal to the circular flat plate-shaped back yoke 177. An electric wire is wound around the first yoke 171 to constitute a coil L11, and the first magnetic pole 11 is constituted by the first yoke 171 and the coil L11. An electric wire is wound around the second yoke 172 to constitute a coil L12, and the second magnetic pole 12 is constituted by the second yoke 172 and the coil L12. An electric wire is wound around the third yoke 173 to constitute a coil L13, and the third magnetic pole 13 is constituted by the third yoke 173 and the coil L13. An electric wire is wound around the fourth yoke 174 to constitute a coil L14, and the fourth magnetic pole 14 is constituted by the fourth yoke 174 and the coil L14. An electric wire is wound around the fifth yoke 175 to constitute a coil L15, and the fifth magnetic pole 15 is constituted by the fifth yoke 175 and the coil L15. An electric wire is wound around the sixth yoke 176 to constitute a coil L16. The sixth yoke 176 and the coil L16 constitute the sixth magnetic pole 16. The back yoke 177 is a base portion of the multi-yoke type magnetizer 10.

The coil L11 of the first magnetic pole 11, the coil L13 of the third magnetic pole 13, and the coil L15 of the fifth magnetic pole 15 are connected by a Y connection with the end of winding of the electric wire connected to the neutral point. The coil L12 of the second magnetic pole 12, the coil L14 of the fourth magnetic pole 14, and the coil L16 of the sixth magnetic pole 16 are connected by a Y connection with the winding start of the wire connected to the neutral point. The connection terminal T1 is connected to the start of winding of the coil L11 of the first magnetic pole 11 and the end of winding of the coil L14 of the fourth magnetic pole 14. The connection terminal T2 is connected to the start of winding of the coil L13 of the third magnetic pole 13 and the end of winding of the coil L16 of the sixth magnetic pole 16. The connection terminal T3 is connected to the start of winding of the coil L15 of the fifth magnetic pole 15 and the end of winding of the coil L12 of the second magnetic pole 12.
The Y connection formed by the coil L11 of the first magnetic pole 11, the coil L13 of the third magnetic pole 13, and the coil L15 of the fifth magnetic pole 15, the coil L12 of the second magnetic pole 12, the coil L14 of the fourth magnetic pole 14, and the The Y connection formed by the coil L16 of the six magnetic poles 16 may connect the neutral points or may not connect the neutral points.

<Formation of rotating magnetic field by multi-yoke magnetizer>
The rotational magnetic flux density in the XY plane on the surface of the object to be inspected formed by the multi-yoke magnetizer 10 will be described with reference to FIGS.

  FIG. 5 is a timing chart illustrating the output voltage waveform of the three-phase AC power supply. FIG. 6 is a timing chart illustrating voltage waveforms VL <b> 1 to VL <b> 6 of the coils L <b> 11 to L <b> 16 of the multi-yoke type magnetizer 10.

  A three-phase AC voltage is applied to the connection terminals T1 to T3 of the multi-yoke magnetizer 10. More specifically, for example, the U phase of the three-phase AC power supply is connected to the connection terminal T1 to which the winding start of the coil L11 of the first magnetic pole 11 and the winding end of the coil L14 of the fourth magnetic pole 11 are connected. The V phase of the three-phase AC power supply is connected to the connection terminal T2 to which the winding start of the third magnetic pole coil L13 and the winding end of the sixth magnetic pole coil L16 are connected. The W phase of the three-phase AC power source is connected to the connection terminal T3 to which the winding start of the fifth magnetic pole coil L15 and the winding end of the second magnetic pole coil L12 are connected.

  Here, based on the phase of the AC voltage VL1 (U phase) applied to the coil L11 of the first magnetic pole 11, the AC voltage VL3 whose phase is shifted by 120 degrees is applied to the coil L13 of the third magnetic pole 13, The AC voltage VL5 whose phase is shifted by 240 degrees is applied to the coil L15 of the five magnetic poles 15. The coil L12 of the second magnetic pole 12, the coil L14 of the fourth magnetic pole 14, and the coil L16 of the sixth magnetic pole 16 are replaced with the coil L11 of the first magnetic pole 11, the coil L13 of the third magnetic pole 13, and the coil L15 of the fifth magnetic pole 15. On the other hand, the winding direction is reversed. Therefore, an AC voltage whose phase is shifted by 180 degrees from the U-phase AC voltage is applied to the coil L14 of the fourth magnetic pole 14. Similarly, an AC voltage that is 180 degrees out of phase from the V-phase AC voltage is applied to the coil L16 of the sixth magnetic pole 16, and a phase that is 180 degrees from the W-phase AC voltage is applied to the coil L12 of the second magnetic pole 12. A shifted AC voltage is applied.

  Therefore, the AC voltage VL2 whose phase is shifted by 60 degrees with respect to the AC voltage VL1 applied to the coil L11 of the first magnetic pole 11 is applied to the coil L12 of the second magnetic pole 12. The AC voltage VL4 having a phase shifted by 180 degrees with respect to the AC voltage VL1 (U phase) applied to the coil L11 of the first magnetic pole 11 is applied to the coil L14 of the fourth magnetic pole 14. The AC voltage VL6 having a phase shifted by 300 degrees with respect to the AC voltage VL1 applied to the coil L11 of the first magnetic pole 11 is applied to the coil L16 of the sixth magnetic pole 16.

  That is, the multi-yoke type magnetizer 10 applies a three-phase AC voltage so that an AC voltage whose phase is shifted by 60 degrees with respect to the AC voltage applied to the coil L11 of the first magnetic pole 11 is a coil of the second magnetic pole 12. An AC voltage that is applied to L12 and is 120 degrees out of phase is applied to the coil L13 of the third magnetic pole 13, and an AC voltage that is 180 degrees out of phase is applied to the coil L14 of the fourth magnetic pole 14 and is 240 degrees out of phase. The AC voltage applied to the coil L15 of the fifth magnetic pole 15 is applied to the coil L16 of the sixth magnetic pole 16 with an AC voltage whose phase is shifted by 300 degrees. That is, in the multi-yoke magnetizer 10 according to the present invention, an AC voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetic poles 11 to 16 by applying a three-phase AC voltage. Thereby, the multi-yoke magnetizer 10 according to the present invention can form a rotating magnetic field with high uniformity with a small deviation of the rotating magnetic flux density on the surface of the object to be inspected.

  As described above, according to the present invention, it is possible to provide a magnetizer capable of forming a rotating magnetic field with high uniformity with a small deviation of rotating magnetic flux density on the surface of an object to be inspected over a wide range. In the multi-yoke magnetizer 10 according to the present invention, the first to sixth magnetic poles 11 to 16 are preferably disposed on the concentric circle B (FIG. 1). Although this is not an essential component of the present invention, the magnetic field strength in each direction of the rotating magnetic field can be made more uniform, thereby further reducing the bias of the rotating magnetic flux density on the surface of the object to be inspected. Can do.

  7 to 9 are Lissajous waveform diagrams of the rotating magnetic flux density on the surface of the test object magnetized by the multi-yoke type magnetizer 10 and the conventional split yoke type magnetizer.

  In order to further verify the effect of the present invention, the applicant analyzed the Lissajous waveforms of the multi-yoke magnetizer 10 according to the present invention and the split yoke magnetizer of the prior art and the respective rotational magnetic flux densities by computer simulation and compared them. did. Specifically, the Lissajous waveform of the rotating magnetic flux density was analyzed by computer simulation at measurement points P1 to P3 (FIG. 1) at XY coordinates (unit: mm) with the center point A of the magnetic pole arrangement as the origin. As analysis conditions for the Lissajous waveform, the number of coil turns of each magnetic pole was 270 turns, and the maximum value of the excitation current was 9.56A. The yoke material was a silicon steel plate and a laminated steel plate with an occupation ratio of 95%, and the test object was a 13 chromium steel (SUS410) ferromagnetic steel plate. The prior art split yoke type magnetizer has two magnetic poles facing each other at a split angle of 120 degrees as one magnetizing element, and three such magnetizing elements are arranged concentrically with a phase difference of 120 degrees.

FIG. 7 is a Lissajous waveform on the XY plane at the measurement point P1 (XY coordinates 0, 0).
The Lissajous waveform at the measurement point P1 (XY coordinates 0, 0), that is, the center point A of the magnetic pole arrangement, is a circular shape of the multi-yoke magnetizer 10 according to the present invention and the conventional split yoke magnetizer. It was. This means that the rotating magnetic flux density in each direction of the XY plane on the surface of the object to be inspected is uniform.

8 shows a Lissajous waveform on the XY plane at the measurement point P2 (XY coordinates 50, 0), and FIG. 9 shows a Lissajous waveform on the XY plane at the measurement point P3 (XY coordinates 50, 40). is there.
From the Lissajous waveform at the measurement point P2 (XY coordinates 50, 0) and the measurement point P3 (XY coordinates 50, 40), the prior art split yoke magnetizer is positioned away from the center point A of the magnetic pole arrangement. Then, it turns out that the deviation has arisen in the rotational magnetic flux density of each direction of the XY plane in the surface of a to-be-inspected object. On the other hand, the Lissajous waveform of the multi-yoke magnetizer 10 according to the present invention is closer to a circle than the Lissajous waveform of the conventional split yoke magnetizer. This is because the multi-yoke magnetizer 10 according to the present invention has a smaller rotational magnetic flux density bias on the surface of the object to be inspected than the conventional split yoke magnetizer, and the rotational magnetic flux density in each direction on the XY plane is smaller. It means that the uniformity is higher than that of the prior art split yoke magnetizer.
In the multi-yoke magnetizer 10 of the first embodiment, the connection relationship between the winding start and the winding end of the coils L11 to L16 can be reversed.

<Second Example of Multi-Yoke Magnetizer Configuration>
A second embodiment of the configuration of the multi-yoke magnetizer 10 according to the present invention will be described with reference to FIG.
FIG. 10 is a connection diagram of the multi-yoke magnetizer 10 of the second embodiment.

  The multi-yoke magnetizer 10 of the second embodiment has the same configuration as that of the multi-yoke magnetizer 10 of the first embodiment except that the connections of the coils L11 to L16 are different. The detailed description is omitted.

  In the multi-yoke magnetizer 10 of the second embodiment, the coil L11 of the first magnetic pole 11, the coil L13 of the third magnetic pole 13, and the coil L15 of the fifth magnetic pole 15 are connected to the neutral point at the winding end of the wire. Connected with Y connection. In the multi-yoke magnetizer 10 of the second embodiment, the winding start of the coil L11 of the first magnetic pole 11 and the winding start of the coil L14 of the fourth magnetic pole 14 are connected, and the winding start of the coil L13 of the third magnetic pole 13 is started. Is connected to the start of winding of the coil L16 of the sixth magnetic pole, and the start of winding of the coil L15 of the fifth magnetic pole 15 is connected to the start of winding of the coil L12 of the second magnetic pole. The end of winding of the coil L14 of the fourth magnetic pole 14 is connected to the connection terminal T1. The end of winding of the coil L16 of the sixth magnetic pole 16 is connected to the connection terminal T2. The end of winding of the coil L12 of the second magnetic pole 12 is connected to the connection terminal T3.

Connect the U phase of the three-phase AC power supply to the connection terminal T1, connect the V phase of the three-phase AC power supply to the connection terminal T2, connect the W phase of the three-phase AC power supply to the connection terminal T3, A three-phase AC voltage is applied to the vessel 10. As a result, in the multi-yoke magnetizer 10 of the second embodiment, an AC voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetic poles 11 to 16 as in the first embodiment. Thus, a highly uniform rotating magnetic field with a small deviation in rotating magnetic flux density on the surface of the object to be inspected can be formed over a wide range.
In the multi-yoke magnetizer 10 of the second embodiment, the connection relationship between the winding start and the winding end of the coils L11 to L16 can be reversed.

<Third Embodiment of Multi-Yoke Magnetizer Configuration>
A third embodiment of the configuration of the multi-yoke magnetizer 10 according to the present invention will be described with reference to FIG.
FIG. 11 is a connection diagram of the multi-yoke magnetizer 10 of the third embodiment.

  The multi-yoke magnetizer 10 of the third embodiment has the same configuration as the multi-yoke magnetizer 10 of the first embodiment except that the connections of the coils L11 to L16 are different. The detailed description is omitted.

  In the multi-yoke magnetizer 10 of the third embodiment, the coil L11 of the first magnetic pole 11, the coil L13 of the third magnetic pole 13, and the coil L15 of the fifth magnetic pole 15 are connected by Δ connection. Similarly, the coil L12 of the second magnetic pole 12, the coil L14 of the fourth magnetic pole 14, and the coil L16 of the sixth magnetic pole 16 are connected by Δ connection. More specifically, the connection terminal T1 includes the start of winding of the coil L11 of the first magnetic pole 11 and the coil L16 of the sixth magnetic pole 16, and the end of winding of the coil L13 of the third magnetic pole 13 and the coil L14 of the fourth magnetic pole 14. Is connected. The connection terminal T2 is connected to the start of winding of the coil L12 of the second magnetic pole 12 and the coil L13 of the third magnetic pole 13, and the end of winding of the coil L15 of the fifth magnetic pole 15 and the coil L16 of the sixth magnetic pole 16. . The connection terminal T3 is connected to the start of winding of the coil L14 of the fourth magnetic pole 14 and the coil L15 of the fifth magnetic pole 15 and the end of winding of the coil L11 of the first magnetic pole 11 and the coil L12 of the second magnetic pole 12. .

Connect the U phase of the three-phase AC power supply to the connection terminal T1, connect the V phase of the three-phase AC power supply to the connection terminal T2, connect the W phase of the three-phase AC power supply to the connection terminal T3, A three-phase AC voltage is applied to the vessel 10. As a result, in the multi-yoke magnetizer 10 of the third embodiment, an AC voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetic poles 11 to 16 as in the first embodiment. Thus, a highly uniform rotating magnetic field with a small deviation in rotating magnetic flux density on the surface of the object to be inspected can be formed over a wide range.
In the multi-yoke type magnetizer 10 of the third embodiment, the connection relationship between the winding start and winding end of the coils L11 to L16 can be reversed.

<Fourth Example of Configuration of Multi-Yoke Magnetizer>
A fourth embodiment of the configuration of the multi-yoke magnetizer 10 according to the present invention will be described with reference to FIG.
FIG. 12 is a connection diagram of the multi-yoke type magnetizer 10 of the fourth embodiment.

  The multi-yoke magnetizer 10 of the fourth embodiment has the same configuration as that of the multi-yoke magnetizer 10 of the first embodiment except that the connections of the coils L11 to L16 are different. The detailed description is omitted.

  In the multi-yoke magnetizer 10 of the fourth embodiment, the winding end of the coil L11 of the first magnetic pole 11 and the winding end of the coil L14 of the fourth magnetic pole 14 are connected, and the winding end of the coil L13 of the third magnetic pole 13 is connected. The winding end of the coil L16 of the sixth magnetic pole 16 is connected, and the winding end of the coil L15 of the fifth magnetic pole 15 and the winding end of the coil L12 of the second magnetic pole 15 are connected. In the multi-yoke magnetizer 10 of the fourth embodiment, the winding start of the coil L11 of the first magnetic pole 11 and the winding start of the coil L16 of the sixth magnetic pole 16 are connected, and the winding start of the coil L12 of the second magnetic pole 12 is started. And the start of winding of the coil L13 of the fourth magnetic pole 14 and the start of winding of the coil L15 of the fifth magnetic pole 15 are connected.

  A connection point between the start of winding of the coil L11 of the first magnetic pole 11 and the start of winding of the coil L16 of the sixth magnetic pole 16 is connected to the connection terminal T1. A connection point between the start of winding of the coil L12 of the second magnetic pole 12 and the start of winding of the coil L13 of the third magnetic pole 13 is connected to the connection terminal T2. A connection point between the start of winding of the coil L14 of the fourth magnetic pole 14 and the start of winding of the coil L15 of the fifth magnetic pole 15 is connected to the connection terminal T3.

Connect the U phase of the three-phase AC power supply to the connection terminal T1, connect the V phase of the three-phase AC power supply to the connection terminal T2, connect the W phase of the three-phase AC power supply to the connection terminal T3, A three-phase AC voltage is applied to the vessel 10. As a result, in the multi-yoke type magnetizer 10 of the fourth embodiment, an AC voltage whose phase is shifted by 60 degrees is applied to the first to sixth magnetic poles 11 to 16 as in the first embodiment. Thus, a highly uniform rotating magnetic field with a small deviation in rotating magnetic flux density on the surface of the object to be inspected can be formed over a wide range.
In the multi-yoke magnetizer 10 of the fourth embodiment, the connection relationship between the winding start and the winding end of the coils L11 to L16 can be reversed.

DESCRIPTION OF SYMBOLS 10 Multi-yoke type magnetizers 11-16 First to sixth magnetic poles 17 Multi-yoke 171 First to sixth yokes 177 Back yokes L11 to L16 Coils T1 to T3 Connection terminals

Claims (5)

The first to sixth magnetization elements are arranged in order with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke,
The first magnetizing element, the third magnetizing element, and the fifth magnetizing element are connected by a Y connection with the winding end of the wire connected to a neutral point,
The second magnetizing element, the fourth magnetizing element, and the sixth magnetizing element are connected by a Y connection with the winding start of the electric wire connected to the neutral point,
The winding start of the first magnetization element and the winding end of the fourth magnetization element are connected, and the winding start of the third magnetization element and the winding end of the sixth magnetization element are connected. The multi-yoke magnetizer is characterized in that the winding start of the electric wire of the fifth magnetization element and the winding end of the electric wire of the second magnetization element are connected. The first to sixth magnetization elements are arranged in order with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke,
The first magnetizing element, the third magnetizing element, and the fifth magnetizing element are connected by a Y connection with the winding end of the wire connected to a neutral point,
The winding start of the first magnetization element and the winding start of the fourth magnetization element are connected, and the winding start of the third magnetization element and the winding start of the sixth magnetization element are connected. A multi-yoke magnetizer, wherein the start of winding of the electric wire of the fifth magnetizing element and the start of winding of the electric wire of the second magnetizing element are connected. The first to sixth magnetization elements are arranged in order with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke,
The first magnetization element, the third magnetization element, and the fifth magnetization element are connected by a Δ connection,
The second magnetization element, the fourth magnetization element, and the sixth magnetization element are connected by a Δ connection,
The winding start of the electric wires of the first magnetization element and the sixth magnetization element and the winding end of the electric wires of the third magnetization element and the fourth magnetization element are connected,
The winding start of the electric wires of the second magnetization element and the third magnetization element and the winding end of the electric wires of the fifth magnetization element and the sixth magnetization element are connected,
A multi-yoke magnetizer, characterized in that the winding start of the electric wires of the fourth and fifth magnetization elements and the winding end of the electric wires of the first and second magnetization elements are connected. . The first to sixth magnetization elements are arranged in order with a phase difference of 60 degrees from each other, and an electric wire is wound around a yoke,
The winding end of the first magnetization element and the winding end of the fourth magnetization element are connected, and the winding end of the third magnetization element and the winding end of the sixth magnetization element are connected. The end of winding of the wire of the fifth magnetizing element and the end of winding of the wire of the second magnetizing element are connected,
The winding start of the first magnetization element and the winding start of the sixth magnetization element are connected, and the winding start of the second magnetization element and the winding start of the third magnetization element are connected. The multi-yoke magnetizer is characterized in that the start of winding of the electric wire of the fourth magnetizing element and the start of winding of the electric wire of the fifth magnetizing element are connected.   5. The multi-yoke magnetizer according to claim 1, wherein the first to sixth magnetizing elements are arranged concentrically. 6.

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