JP6289857B2 - Magnetizing method for test object, magnetizing device for test object, magnetic particle flaw detector - Google Patents

Description

  The present invention relates to a magnetization method for magnetizing an object to be inspected in magnetic particle flaw detection, a magnetization apparatus for magnetizing the object to be inspected, and a magnetic particle inspection apparatus including a magnetization apparatus for the object to be inspected.

  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 magnetic lines of force are perpendicular to the longitudinal direction of 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 powders attached to the scratches and cracks is the clearest Can be identified.

  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 such a prior art, three magnetizing elements each having a wire wound around a yoke are arranged with a phase difference of 120 degrees from each other, and the three magnetizing elements are connected in a Δ connection or a Y connection. A magnetizing apparatus for an object to be inspected using a pole yoke is known. More specifically, two three-pole yokes are arranged to face each other with the object to be inspected, and a three-phase AC voltage is applied to each of the two three-pole yokes, and three three-pole yokes are applied to one of the three-pole yokes. A magnetizing apparatus for an object to be inspected is known in which the frequency of the phase AC voltage is not multiplied by the frequency of the three-phase AC voltage applied to the other three-pole yoke (see, for example, Patent Document 1). According to the related art, a rotating magnetic field (a magnetic field in which the direction of the line of magnetic force changes in a 360-degree plane) can be formed on each of the XY plane, the YZ plane, and the ZX plane. It is possible to realize a magnetic particle flaw detector capable of obtaining high magnetic particle flaw detection accuracy over the entire surface of the plane, the YZ plane, and the ZX plane.
Here, the XY plane is a plane along the X axis and the Y axis, the YZ plane is a plane along the Y axis and the Z axis, and the ZX plane is along the Z axis and the X axis. It is a plane along. The X axis, the Y axis, and the Z axis are coordinate axes in an orthogonal coordinate system in a three-dimensional space, the X axis and the Y axis are orthogonal, and the Z axis is an axis that is orthogonal to both the X axis and the Y axis. It is.

JP 2012-198087 A

  By the way, in a magnetizing apparatus for an object to be inspected, in order to magnetize the object to be inspected more efficiently and in a short time, it is desirable to dispose the object to be inspected as close to the magnetizer as possible. However, when the distance between the magnetizer and the object to be inspected is shortened, the object to be inspected is attracted by the magnetic force of the magnetizer and comes into contact with the magnetizer, so that the object to be inspected or the magnetizer may be damaged. . In particular, in order to efficiently magnetize the YZ plane and the ZX plane of the object to be inspected in a short time, the object to be inspected may be magnetized while being rotated at a rotation speed suitable for the shape and the like. However, it is often difficult to firmly support the object to be inspected in a rotatable state, and the possibility that the object to be inspected will come into contact with the magnetizer by the attractive force of the magnetizer as described above. Therefore, the distance between the object to be inspected and the magnetizer must be increased.

  For this reason, instead of rotating the object to be inspected, the inspected object is firmly fixed, and depending on the shape of the object to be inspected, the direction component of the magnetic field in the YZ plane and the ZX plane There is a request to adjust. However, in the conventional technique disclosed in the above-mentioned Patent Document 1, the directional component of the magnetic field in the YZ plane and the ZX plane depends on the ratio of two AC frequencies that are not multiplied. Therefore, in the conventional technique disclosed in Patent Document 1 above, when the frequency of the three-phase AC voltage applied to the two three-pole yokes is fixed, the magnetic field generated in the YZ plane and the ZX plane is reduced. The direction component cannot be adjusted. In addition, in order to be able to adjust the direction component of the magnetic field generated in the YZ plane and the ZX plane, a power converter capable of adjusting the frequency of at least one of the three-phase AC voltages applied to the two three-pole yokes. Therefore, there is a risk that the cost of the magnetizing device for the object to be inspected increases.

  In view of such circumstances, the present invention has been made, and its purpose is to adjust the direction component of the magnetic field generated in the YZ plane and the ZX plane to magnetize the object to be inspected. The object is to realize a magnetizing method of a test object and a magnetizing apparatus of a test object with a simple system.

<First Aspect of the Present Invention>
In the first aspect of the present invention, three magnetizing elements each having a wire wound around a yoke are arranged with a phase difference of 120 degrees from each other, and the wires of the three magnetizing elements are Δ-connected or Y-connected. A first magnetizer, and a second magnetizer in which three magnetizing elements each having a wire wound around a yoke are arranged with a phase difference of 120 degrees, and the electric wires of the three magnetizing elements are Δ-connected or Y-connected Are arranged opposite to each other with the object to be inspected, and a three-phase AC voltage is applied to the first magnetizer and the second magnetizer, and the first magnetizer is fixed. It is a magnetization method for an object to be inspected, in which magnetic particles are scattered on the object to be inspected while rotating the second magnetizer with the central axis of three magnetization elements as a rotation axis.

  The first magnetizer and the second magnetizer are composed of three magnetizing elements arranged with a phase difference of 120 degrees from each other. Therefore, by applying a three-phase AC voltage to the first magnetizer and the second magnetizer, it is possible to form a rotating magnetic field in which the strength of the magnetic field is approximately 360 degrees in a plane. Therefore, if the surface where the first and second magnetizers face each other is the XY plane, a rotating magnetic field having a magnetic field strength of 360 degrees in the plane and substantially uniform can be formed in the XY plane. Further, a magnetic field is also formed in the YZ plane and the ZX plane by the rotating magnetic field formed by the first magnetizer on the XY plane and the rotating magnetic field formed by the second magnetizer on the XY plane. Become.

  Then, with the first magnetizer fixed, the second magnetizer is rotated with the central axis of the three magnetizing elements of the second magnetizer as the rotation axis. Then, a phase shift occurs between the rotating magnetic field in the XY plane formed by the first magnetizer and the rotating magnetic field in the XY plane formed by the second magnetizer, and the second magnetizer is further rotated. Accordingly, the phase shift changes. As a result, the direction component of the magnetic field generated in the YZ plane and the ZX plane changes. That is, by rotating the second magnetizer, the direction of the magnetic field generated in the YZ plane and the ZX plane can be changed radially, that is, in any direction. That is, the direction component of the magnetic field generated in the YZ plane and the ZX plane can be adjusted by rotating the second magnetizer. Therefore, in a state where the first magnetizer is fixed, a higher magnetic particle flaw detection is achieved by sprinkling the magnetic particles on the object to be inspected while rotating the second magnetizer around the central axis of the three magnetized elements of the second magnetizer. Accuracy can be obtained.

  As described above, according to the present invention, by rotating the second magnetizer, the frequency of the three-phase AC voltage applied to the first magnetizer and the second magnetizer is not changed, and the YZ plane and the Z- The direction component of the magnetic field generated in the X plane can be adjusted. Therefore, there is no need to provide a power conversion device for generating three-phase AC voltages having different frequencies as in the prior art. The direction component of the magnetic field generated in the YZ plane and the ZX plane can be adjusted very easily by adjusting the rotation speed, rotation position, and the like of the second magnetizer.

  Thus, according to the first aspect of the present invention, there is provided a method for magnetizing a device under test capable of magnetizing the device under test by adjusting the direction component of the magnetic field generated in the YZ plane and the ZX plane. The effect that it can be realized by a simple system is obtained.

<Second Aspect of the Present Invention>
According to a second aspect of the present invention, there is provided a magnetizing method for an object to be inspected, wherein the second magnetizer is rotated 180 degrees or more in the first aspect of the present invention described above.
According to such a feature, the direction component of the magnetic field generated in the YZ plane and the ZX plane can be adjusted in all directions by 360 degrees by rotating at least the second magnetizer by 180 degrees or more.

<Third Aspect of the Present Invention>
In the third aspect of the present invention, three magnetizing elements each having a wire wound around a yoke are arranged with a phase difference of 120 degrees from each other, and the wires of the three magnetizing elements are Δ-connected or Y-connected. One magnetizer and three magnetized elements wound with a wire around a yoke are arranged with a phase difference of 120 degrees from each other, and the wires of the three magnetized elements are Δ-connected or Y-connected, A second magnetizer disposed opposite to the first magnetizer, and a power supply device that applies a three-phase AC voltage to the first magnetizer and the second magnetizer. The test object is fixedly supported, and the second magnetizer is supported rotatably about the central axis of the three magnetizing elements of the first magnetizer. It is a magnetizing device.
According to the third aspect of the present invention, in the magnetization apparatus for an object to be inspected, the above-described method for magnetizing the object to be inspected according to the first aspect of the present invention can be carried out, and thereby the above-described present invention. The effect by the invention as described in the first aspect of the present invention can be obtained.

<Fourth aspect of the present invention>
According to a fourth aspect of the present invention, there is provided the magnetizing apparatus for an object to be inspected according to the third aspect of the present invention described above, wherein the second magnetizer is rotatably supported by 180 degrees or more. is there.
According to the fourth aspect of the present invention, in the magnetizing apparatus for an object to be inspected, the method for magnetizing the object to be inspected according to the second aspect of the present invention described above can be implemented, whereby the present invention described above is performed. The effects of the invention described in the second aspect can be obtained.

<Fifth aspect of the present invention>
According to a fifth aspect of the present invention, in the third aspect or the fourth aspect of the present invention described above, the rotating device further rotates the second magnetizer with the driving force of the driving force source. This is a magnetizing device for an inspection object.
According to such a feature, the direction component of the magnetic field generated in the YZ plane and the ZX plane can be automatically adjusted.

<Sixth aspect of the present invention>
According to a sixth aspect of the present invention, there is provided a magnetic particle flaw detector comprising the magnetizing apparatus for an object to be inspected according to any one of the third to fifth aspects of the present invention described above.
According to the sixth aspect of the present invention, in the magnetic particle flaw detector, the operational effects of the invention according to any one of the third to fifth aspects of the present invention described above can be obtained.

  According to the present invention, there is provided a method for magnetizing an object to be inspected and a magnetizing apparatus for the object to be inspected, which can magnetize the object to be inspected by adjusting the direction component of the magnetic field generated in the YZ plane and the ZX plane. It can be realized with a simple system.

The perspective view of a three pole yoke type | mold magnetizer. The front view of a three pole yoke type magnetizer. Structure and connection diagram of a three-pole yoke type magnetizer. FIG. 6 is a structural diagram and a connection diagram of a modified example of a three-pole yoke type magnetizer. The block diagram which illustrated the structure of the magnetization apparatus of the to-be-inspected object of 1st Example. The connection diagram of the magnetization apparatus of the to-be-inspected object of 1st Example. The block diagram which illustrated the structure of the magnetization apparatus of the to-be-inspected object of 2nd Example. The connection diagram of the magnetization apparatus of the to-be-inspected object of 2nd Example. The top view which illustrated typically the magnetic field which generate | occur | produces in the 1st Example when the rotation angle of the 2nd magnetizer 10b is 0 degree. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 60 degrees in the 1st example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 120 degrees in the 1st example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 180 degrees in the 1st example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 240 degrees in the 1st example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 300 degrees in the 1st example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 0 degrees in the 2nd example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 60 degrees in the 2nd example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 120 degrees in the 2nd example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 180 degrees in the 2nd example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 240 degrees in the 2nd example. The top view which illustrated typically the magnetic field generated when the rotation angle of the 2nd magnetizer 10b is 300 degrees in the 2nd example. The Lissajous waveform of the rotational magnetic flux density of the XY plane of the magnetizing apparatus of the device under test of the first embodiment. The Lissajous waveform of the rotating magnetic flux density of the ZX plane of the magnetizing apparatus of the device under test of the first embodiment. The Lissajous waveform of the rotational magnetic flux density of the YZ plane of the magnetizing apparatus of the device under test of the first embodiment. The Lissajous waveform of the rotational magnetic flux density in the XY plane of the magnetizing apparatus of the device under test of the second embodiment. The Lissajous waveform of the rotating magnetic flux density on the Z-X plane of the magnetizing apparatus of the device under test of the second embodiment. The Lissajous waveform of the rotational magnetic flux density of the YZ plane of the magnetizing apparatus of the device under test of the second embodiment.

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.

<Configuration of three-pole yoke magnetizer>
The configuration of the three-pole yoke magnetizer 10 will be described with reference to FIGS.
FIG. 1 is a perspective view of a three-pole yoke magnetizer 10. FIG. 2 is a front view of the three-pole yoke magnetizer 10. 3 illustrates the configuration of the three-pole yoke magnetizer 10, FIG. 3 (a) is a structural diagram of the three-pole yoke magnetizer 10, and FIG. 3 (b) is a three-pole yoke magnetizer 10. FIG.

  The three-pole yoke magnetizer 10 as the “first magnetizer” and the “second magnetizer” includes a first magnetizing element 11, a second magnetizing element 12, a third magnetizing element 13, a base 14 and a three-pole yoke 15. Including. The first magnetizing element 11, the second magnetizing element 12, and the third magnetizing element 13 are arranged and fixed on the base 14 with a phase difference of 120 degrees from each other.

The three-pole yoke 15 is a yoke formed by laminating silicon steel plates, and has a first magnetic pole 151, a second magnetic pole 152, and a third magnetic pole 153. An electric wire is wound around the first magnetic pole 151 to constitute a coil L11, and the first magnetic element 151 is constituted by the first magnetic pole 151 and the coil L11. An electric wire is wound around the second magnetic pole 152 to constitute a coil L12, and the second magnetic element 152 and the coil L12 constitute the second magnetizing element 12. An electric wire is wound around the third magnetic pole 153 to constitute a coil L13, and the third magnetic element 153 is constituted by the third magnetic pole 153 and the coil L13.
In order to form a stronger magnetic field, it is desirable that the number of turns of the coil L11, the coil L12, and the coil L13 is larger.

  The coil L11, the coil L12, and the coil L13 are Δ-connected. More specifically, the connection point between the coil L11 and the coil L13 is connected to the terminal A1, the connection point between the coil L11 and the coil L12 is connected to the terminal A2, and the connection point between the coil L12 and the coil L13 is the terminal A3. It is connected to the.

  The three-pole yoke magnetizer 10 including the first magnetizing element 11, the second magnetizing element 12, and the third magnetizing element 13 arranged with a phase difference of 120 degrees in this way is connected to the terminals A1 to A3 with a three-phase alternating current. By applying a voltage, it is possible to form a rotating magnetic field in which the strength of the magnetic field is approximately 360 degrees on a plane and is substantially uniform. The first magnetizing element 11, the second magnetizing element 12, and the third magnetizing element 13 are not essential elements of the present invention, but are preferably arranged on concentric circles. As a result, when a three-phase AC voltage is applied to the three-pole yoke magnetizer 10, the strength of the rotating magnetic field formed by the three-pole yoke magnetizer 10 can be made more uniform.

FIG. 4 illustrates a modification of the three-pole yoke type magnetizer 10. FIG. 4 (a) is a structural diagram of the three-pole yoke type magnetizer 10, and FIG. 4 (b) is a three-pole yoke type magnetizer 10. FIG.
The modification of the three-pole yoke magnetizer 10 has the same configuration as that of the three-pole yoke magnetizer 10 shown in FIGS. 1 to 3 except that the coils L11 to L13 are connected differently. In the modification of the three-pole yoke magnetizer 10, the coil L11, the coil L12, and the coil L13 are Y-connected. More specifically, one end of each of the coil L11, the coil L12, and the coil L13 is connected to a common connection point. The other end of the coil L11 is connected to the terminal A1, the other end of the coil L12 is connected to the terminal A2, and the other end of the coil L13 is connected to the terminal A3.

<First Example of Magnetizing Device for Inspected Object>
A first embodiment of a magnetizing apparatus for an object to be inspected according to the present invention will be described with reference to FIGS.
FIG. 5 is a configuration diagram illustrating the configuration of the magnetizing apparatus for an object to be inspected according to the first embodiment. FIG. 6 is a connection diagram of the magnetizing apparatus for the device under test according to the first embodiment.

  The magnetizing device for the device under test of the first embodiment includes a first magnetizer 10a, a second magnetizer 10b, a rotating device 20, and a power supply device 100.

  Each of the first magnetizer 10a and the second magnetizer 10b is the three-pole yoke magnetizer 10 illustrated and described with reference to FIGS. 1 to 4, and the coils L11, L12, and L13 are Δ-connected. The winding directions of the coils L11, L12, and L13 of the first magnetizer 10a and the winding directions of the coils L11, L12, and L13 of the second magnetizer 10b are in the same phase in the first embodiment. More specifically, in each of the first magnetizer 10a and the second magnetizer 10b, the winding start of the coil L11 and the winding end of the coil L13 are connected to the terminal A1, and the winding start of the coil L12 and the winding end of the coil L11 are connected. Connected to terminal A2, the start of winding of coil L13 and the end of winding of coil L12 are connected to terminal A3.

  The first magnetizer 10a is arranged such that the tips of the first magnetizing element 11, the second magnetizing element 12, and the third magnetizing element 13 face the XY plane of the magnetized region 1 in which the device under test is arranged. And fixedly supported. The second magnetizer 10b is disposed to face the first magnetizer 10a with the object to be inspected in between. That is, the second magnetizer 10 b is disposed so that the tips of the first magnetization element 11, the second magnetization element 12, and the third magnetization element 13 face the XY plane of the magnetization region 1. The second magnetizer 10b supports the three magnetizing elements (the first magnetizing element 11, the second magnetizing element 12, and the third magnetizing element 13) so as to be rotatable in the rotation direction indicated by the symbol D with the central axis as the rotation axis. Has been. Here, the central axis of the three magnetizing elements means an axis passing through the center point P (FIG. 2) of the arrangement of the first magnetizing element 11, the second magnetizing element 12, and the third magnetizing element 13 and parallel to the Z axis. means.

  The rotating device 20 includes a motor 21 as a “driving force source” and a rotating shaft 22. The motor 21 is, for example, an electric motor. One end of the rotary shaft 22 is connected to the rotational drive shaft of the motor 21 and the other end is connected to the second magnetizer 10b. That is, the rotating device 20 is a device that rotates the second magnetizer 10 b in the rotation direction illustrated by the symbol D by the rotational driving force of the motor 21.

  The power supply apparatus 100 applies a three-phase AC voltage to the first magnetizer 10a. More specifically, the power supply device 100 connects the R phase of the commercial three-phase AC power source and the terminal A1 of the first magnetizer 10a, and connects the S phase of the commercial three-phase AC power source and the terminal A2 of the first magnetizer 10a. Connect the T phase of the commercial three-phase AC power supply and the terminal A3 of the first magnetizer 10a. The power supply device 100 applies a three-phase AC voltage to the second magnetizer 10b. More specifically, the power supply device 100 connects the R phase of the commercial three-phase AC power source and the terminal A1 of the second magnetizer 10b, and the S phase of the commercial three-phase AC power source and the terminal A2 of the second magnetizer 10b. Are connected, and the T phase of the commercial three-phase AC power supply is connected to the terminal A3 of the second magnetizer 10b.

  In the XY plane, the first magnetizer 10a forms a rotating magnetic field C1 in which the strength of the magnetic field is approximately 360 degrees on the plane and is substantially uniform. On the other side of the XY plane across the magnetized region 1, the second magnetizer 10b forms a rotating magnetic field C2 in which the strength of the magnetic field is approximately 360 degrees in the plane. Therefore, a magnetic field is also formed in the YZ plane and the ZX plane by the rotating magnetic field C1 formed by the first magnetizer 10a and the rotating magnetic field C2 formed by the second magnetizer 10b.

  Then, when the second magnetizer 10b is rotated in the rotation direction D by the rotating device 20 with the first magnetizer 10a fixed, the rotating magnetic field C1 and the second magnetization in the XY plane formed by the first magnetizer 10a. A phase shift occurs between the rotating field C2 in the XY plane formed by the vessel 10b. As the second magnetizer 10b is rotated, the phase shift changes. Thereby, the direction of the magnetic field generated in the YZ plane and the ZX plane can be changed radially, that is, in any direction. That is, the direction component of the magnetic field generated in the YZ plane and the ZX plane can be adjusted by rotating the second magnetizer 10b.

  Therefore, in a state where the first magnetizer 10a is fixed, the magnetic powder is sprinkled on the object to be inspected in the magnetized region 1 while rotating the second magnetizer 10b in the rotation direction D by the rotating device 20, thereby achieving higher magnetic particle flaw detection accuracy. Can be obtained. At this time, the second magnetizer 10b is preferably rotated at least 180 degrees, more preferably 360 degrees or more. Thereby, the direction component of the magnetic field generated in the YZ plane and the ZX plane can be adjusted in all directions of 360 degrees. Further, it goes without saying that the present invention can be implemented even if the second magnetizer 10b is manually rotated in the rotation direction D, for example.

  9 to 14 show the relationship between the first magnetizer 10a and the second magnetizer 10b when the winding directions of the coils L11, L12, and L13 of the first magnetizer 10a and the second magnetizer 10b are the same phase. It is the top view which illustrated typically the magnetic field which generate | occur | produces. 9 shows a rotation angle of the second magnetizer 10b of 0 °, FIG. 10 shows a rotation angle of the second magnetizer 10b of 60 °, FIG. 11 shows a rotation angle of the second magnetizer 10b of 120 °, and FIG. FIG. 13 illustrates a state in which the rotation angle of the magnetizer 10b is 180 °, FIG. 13 illustrates a state in which the rotation angle of the second magnetizer 10b is 240 °, and FIG. 14 illustrates a state in which the rotation angle of the second magnetizer 10b is 300 °.

  9 to 14, for convenience, the first magnetization element 11a, the second magnetization element 12a, and the third magnetization element 13a of the first magnetizer 10a are shown side by side in a line. Similarly, the first magnetizing element 11b, the second magnetizing element 12b, and the third magnetizing element 13b of the second magnetizer 10b are shown in a horizontal row. The polarities of the first magnetization element 11a, the second magnetization element 12a, the third magnetization element 13a, the first magnetization element 11b, the second magnetization element 12b, and the third magnetization element 13b of the first magnetizer 10a. Changes in response to changes in the voltage of the three-phase alternating current. Therefore, in FIGS. 9 to 14, for convenience, the first magnetization element 11 a and the third magnetization element 13 a of the first magnetizer 10 a and the first magnetization element 11 b and the third magnetization element 13 b of the second magnetizer 10 b are N poles. The time point at which the polarities of the second magnetizing element 12a of the first magnetizer 10a and the second magnetizing element 12b of the second magnetizer 10b become the S pole is illustrated as an example.

  In the process in which the rotation angle of the second magnetizer 10b changes by 360 °, the magnetic flux density of the X-axis direction and Y-axis direction components becomes dominant in the region where the magnetized elements having the same polarity face each other. In the region where the magnetized elements having different polarities face each other, the magnetic flux density of the Z-axis direction component is dominant. Therefore, the direction of the magnetic field generated in the YZ plane and the ZX plane can be changed radially, that is, in any direction by rotating the second magnetizer 10b.

  As described above, according to the present invention, by rotating the second magnetizer 10b, the YZ plane can be obtained without changing the frequency of the three-phase AC voltage applied to the first magnetizer 10a and the second magnetizer 10b. And the direction component of the magnetic field generated in the ZX plane can be adjusted. Therefore, there is no need to provide a power conversion device for generating three-phase AC voltages having different frequencies as in the prior art. The direction component of the magnetic field generated in the YZ plane and the ZX plane can be very easily adjusted by adjusting the rotation speed, rotation position, and the like of the second magnetizer 10b. Therefore, according to the present invention, a method for magnetizing an object to be inspected and a magnetization apparatus capable of magnetizing the object to be inspected by adjusting the direction component of the magnetic field generated in the YZ plane and the ZX plane with a simple system. Can be realized.

<Second Embodiment of Magnetizing Device for Inspected Object>
A second embodiment of the magnetizing apparatus for an object to be inspected according to the present invention will be described with reference to FIGS.
FIG. 7 is a configuration diagram illustrating the configuration of a magnetizing apparatus for an object to be inspected according to the second embodiment. FIG. 8 is a connection diagram of the magnetizing apparatus for the device under test of the second embodiment.

In the magnetizing apparatus for the device under test of the second embodiment, the winding directions of the coils L11, L12, L13 of the first magnetizer 10a and the winding directions of the coils L11, L12, L13 of the second magnetizer 10b are in opposite phases. In that respect, the configuration is different from the magnetizing device of the device under test of the first embodiment. More specifically, in the first magnetizer 10a, the winding start of the coil L11 and the winding end of the coil L13 are connected to the terminal A1, the winding start of the coil L12 and the winding end of the coil L11 are connected to the terminal A2, and the coil L13 And the end of winding of the coil L12 are connected to the terminal A3. On the other hand, in the second magnetizer 10b, the winding start of the coil L13 and the winding end of the coil L11 are connected to the terminal A1, the winding start of the coil L11 and the winding end of the coil L12 are connected to the terminal A2, and the winding start of the coil L12 is started. The end of winding of the coil L13 is connected to the terminal A3.
Since the rest of the configuration is the same as that of the magnetizing apparatus for the device under test of the first embodiment, a detailed description thereof will be omitted.

  Similarly to the first embodiment, when the second magnetizer 10b is rotated in the rotation direction D by the rotating device 20 with the first magnetizer 10a fixed, the XY plane formed by the first magnetizer 10a is rotated. A phase shift occurs between the rotating magnetic field C1 and the rotating magnetic field C2 in the XY plane formed by the second magnetizer 10b. As the second magnetizer 10b is rotated, the phase shift changes. Thereby, the direction of the magnetic field generated in the YZ plane and the ZX plane can be changed radially, that is, in any direction. That is, the direction component of the magnetic field generated in the YZ plane and the ZX plane can be adjusted by rotating the second magnetizer 10b.

  FIGS. 15 to 20 show the relationship between the first magnetizer 10a and the second magnetizer 10b when the winding directions of the coils L11, L12, and L13 of the first magnetizer 10a and the second magnetizer 10b are opposite in phase. It is the top view which illustrated typically the magnetic field which generate | occur | produces. 15 shows that the rotation angle of the second magnetizer 10b is 0 °, FIG. 16 shows that the rotation angle of the second magnetizer 10b is 60 °, FIG. 17 shows that the rotation angle of the second magnetizer 10b is 120 °, and FIG. FIG. 19 illustrates a state where the rotation angle of the magnetizer 10b is 180 °, FIG. 19 illustrates a state where the rotation angle of the second magnetizer 10b is 240 °, and FIG. 20 illustrates a state where the rotation angle of the second magnetizer 10b is 300 °.

  15 to 20, for convenience, the first magnetizing element 11a, the second magnetizing element 12a, and the third magnetizing element 13a of the first magnetizer 10a are shown in a horizontal row. Similarly, the first magnetizing element 11b, the second magnetizing element 12b, and the third magnetizing element 13b of the second magnetizer 10b are shown in a horizontal row. The polarities of the first magnetization element 11a, the second magnetization element 12a, the third magnetization element 13a, the first magnetization element 11b, the second magnetization element 12b, and the third magnetization element 13b of the first magnetizer 10a. Changes in response to changes in the voltage of the three-phase alternating current. Therefore, in FIGS. 15 to 20, for convenience, the first magnetization element 11 a and the third magnetization element 13 a of the first magnetizer 10 a and the second magnetization element 12 b of the second magnetizer 10 b are N poles, and the first magnetizer 10 a. The time when the polarities of the second magnetizing element 12a and the first magnetizing element 11b and the third magnetizing element 13b of the second magnetizer 10b become S poles is shown as an example.

  Similar to the first embodiment, in the process in which the rotation angle of the second magnetizer 10b changes by 360 °, the magnetic flux densities of the X-axis direction and Y-axis direction components are dominant in the region where the magnetized elements having the same polarity face each other. Become. In the region where the magnetized elements having different polarities face each other, the magnetic flux density of the Z-axis direction component is dominant. Therefore, the direction of the magnetic field generated in the YZ plane and the ZX plane can be changed radially, that is, in any direction by rotating the second magnetizer 10b. Therefore, as in the first embodiment, while the first magnetizer 10a is fixed, the rotating device 20 causes the second magnetizer 10b to rotate in the rotation direction D while spreading the magnetic powder on the object to be inspected in the magnetization region 1. Therefore, higher magnetic particle flaw detection accuracy can be obtained.

<Analysis by computer simulation>
In order to further verify the effect of the present invention, the applicant has analyzed the Lissajous waveform of the magnetic flux density distribution on the surface of the test object when the test object is magnetized with the magnetizing apparatus for the test object according to the present invention under the following analysis conditions: And analyzed by computer simulation.

The three-pole yoke 15 of the three-pole yoke type magnetizer 10 has an electric resistivity of 4.5 × 10 ⁻⁷ Ω / m, a space factor of 95%, and a magnetic permeability that is a non-linear BH curve. The dimensions of 151 to 153 were 50 mm × 60 mm × 230 mm. The coils L11 to L13 had a winding number of 270 turns and a Y connection. The exciting current was a sinusoidal alternating current with a frequency of 50 Hz and a maximum value of 8.06 A. In the magnetization region 1 between the first magnetizer 10a and the second magnetizer 10b, SUS410 (13 chrome steel) was disposed as a ferromagnetic steel material. The ferromagnetic steel material is a cube of 50 mm × 50 mm × 50 mm, the magnetic permeability is a non-linear BH curve, the distance between the first magnetizer 10a and the ferromagnetic steel material, and the distance between the second magnetizer 10b and the ferromagnetic steel material. Were each 10 mm. Then, the first magnetizer 10a and the second magnetizer 10b are made to face each other so that the arrangement angles of the first to third magnetic poles 151 to 153 are shifted by 180 degrees, and the second magnetizer 10b is set as a reference position. Of the rotating magnetic flux density on the XY plane, the YZ plane, and the ZX plane on the surface of the ferromagnetic steel material when the was rotated by 60 degrees was analyzed.

  FIGS. 21 to 23 show the analysis results of the magnetizing device (first embodiment) of the device under test in which the winding directions of the coils L11, L12, and L13 of the first magnetizer 10a and the second magnetizer 10b are in the same phase. This is a Lissajous waveform.

  FIG. 21 is a Lissajous waveform of the rotating magnetic flux density in the XY plane. The horizontal axis Bx is the magnetic flux density of the X-axis direction component, the vertical axis By is the magnetic flux density of the Y-axis direction component, and the units are both Tesla [T]. From the Lissajous waveform of the rotational magnetic flux density in the XY plane (FIG. 21), the rotational magnetic flux density in the XY plane has a magnetic field strength of 360 degrees regardless of the rotational angle of the second magnetizer 10b. It can be seen that a rotating magnetic field that is substantially uniform is formed.

FIG. 22 is a Lissajous waveform of the rotating magnetic flux density in the ZX plane. The horizontal axis Bx is the magnetic flux density of the X-axis direction component, the vertical axis Bz is the magnetic flux density of the Z-axis direction component, and the units are both Tesla [T].
Regarding the rotational magnetic flux density in the Z-X plane, first, when the rotational angle of the second magnetizer 10b is 0 degrees, the magnetic flux density of the X-axis direction component becomes the most dominant. As the second magnetizer 10b is rotated to a rotation angle of 60 degrees and 120 degrees, the magnetic flux density of the X-axis direction component decreases and the magnetic flux density of the Z-axis direction component increases. The magnetic flux density of the Z-axis direction component is most dominant when the rotation angle is between 180 degrees and 240 degrees. When the second magnetizer 10b is further rotated to a rotation angle of 240 degrees and 300 degrees, the magnetic flux density of the Z-axis direction component decreases and the magnetic flux density of the X-axis direction component increases, and the second magnetizer 10b. Is rotated 360 degrees, the magnetic flux density of the X-axis direction component becomes the most dominant again. That is, from the Lissajous waveform of the rotating magnetic flux density on the ZX plane (FIG. 22), the direction component of the magnetic field generated on the ZX plane can be adjusted in all directions by rotating the second magnetizer 10b. I understand.

FIG. 23 is a Lissajous waveform of the rotating magnetic flux density in the YZ plane. The horizontal axis By is the magnetic flux density of the Y-axis direction component, the vertical axis Bz is the magnetic flux density of the Z-axis direction component, and the unit is Tesla [T].
As for the rotational magnetic flux density in the YZ plane, first, when the rotational angle of the second magnetizer 10b is 0 degree, the magnetic flux density of the Y-axis direction component becomes the most dominant. As the second magnetizer 10b is rotated to a rotation angle of 60 degrees and 120 degrees, the magnetic flux density of the Y-axis direction component decreases and the magnetic flux density of the Z-axis direction component increases, and the second magnetizer 10b When the rotation angle is 180 degrees, the magnetic flux density of the Z-axis direction component is most dominant. When the second magnetizer 10b is further rotated to a rotation angle of 240 degrees and 300 degrees, the magnetic flux density of the Z-axis direction component decreases and the magnetic flux density of the Y-axis direction component increases, and the second magnetizer 10b. Is rotated 360 degrees, the magnetic flux density of the Y-axis direction component becomes the most dominant again. That is, from the Lissajous waveform of the rotational magnetic flux density on the YZ plane (FIG. 23), the direction component of the magnetic field generated on the YZ plane can be adjusted in all directions by rotating the second magnetizer 10b. I understand.

  24 to 26 show the analysis results of the magnetizing device (second embodiment) of the device under test in which the winding directions of the coils L11, L12, and L13 of the first magnetizer 10a and the second magnetizer 10b are opposite in phase. This is a Lissajous waveform.

  FIG. 24 is a Lissajous waveform of the rotating magnetic flux density in the XY plane. The horizontal axis Bx is the magnetic flux density of the X-axis direction component, the vertical axis By is the magnetic flux density of the Y-axis direction component, and the units are both Tesla [T]. From the Lissajous waveform of the rotational magnetic flux density on the XY plane (FIG. 24), the rotational magnetic flux density on the XY plane is almost uniform with the magnetic field strength of 360 degrees regardless of the rotational angle of the second magnetizer 10b. It can be seen that a rotating magnetic field is formed.

FIG. 25 is a Lissajous waveform of the rotating magnetic flux density in the ZX plane. The horizontal axis Bx is the magnetic flux density of the X-axis direction component, the vertical axis Bz is the magnetic flux density of the Z-axis direction component, and the units are both Tesla [T].
Regarding the rotational magnetic flux density in the Z-X plane, first, when the rotational angle of the second magnetizer 10b is 0 degree, the magnetic flux density of the Z-axis direction component becomes the most dominant. Then, as the second magnetizer 10b is rotated to a rotation angle of 60 degrees and 120 degrees, the magnetic flux density of the Z-axis direction component decreases and the magnetic flux density of the X-axis direction component increases, and the second magnetizer 10b When the rotation angle is 180 degrees, the magnetic flux density of the X-axis direction component is most dominant. When the second magnetizer 10b is further rotated to a rotation angle of 240 degrees and 300 degrees, the magnetic flux density of the X-axis direction component decreases and the magnetic flux density of the Z-axis direction component increases, and the second magnetizer 10b. Is rotated 360 degrees, the magnetic flux density of the Z-axis direction component becomes the most dominant again. That is, from the Lissajous waveform of the rotating magnetic flux density on the ZX plane (FIG. 24), the direction component of the magnetic field generated on the ZX plane can be adjusted in all directions by rotating the second magnetizer 10b. I understand.

FIG. 26 is a Lissajous waveform of the rotating magnetic flux density in the YZ plane. The horizontal axis By is the magnetic flux density of the Y-axis direction component, the vertical axis Bz is the magnetic flux density of the Z-axis direction component, and the unit is Tesla [T].
Regarding the rotational magnetic flux density in the YZ plane, first, the magnetic flux density of the Z-axis direction component is most dominant when the rotational angle of the second magnetizer 10b is 0 degree. Then, as the second magnetizer 10b is rotated to rotation angles of 60 degrees and 120 degrees, the magnetic flux density of the Z-axis direction component decreases and the magnetic flux density of the Y-axis direction component increases, and the second magnetizer 10b When the rotation angle is between 120 degrees and 180 degrees, the magnetic flux density of the Y-axis direction component becomes the most dominant. When the second magnetizer 10b is further rotated to a rotation angle of 240 degrees and 300 degrees, the magnetic flux density of the Y-axis direction component decreases and the magnetic flux density of the Z-axis direction component increases, and the second magnetizer 10b. Is rotated 360 degrees, the magnetic flux density of the Z-axis direction component becomes the most dominant again. That is, from the Lissajous waveform of the rotational magnetic flux density on the YZ plane (FIG. 26), the direction component of the magnetic field generated on the YZ plane can be adjusted in all directions by rotating the second magnetizer 10b. I understand.

DESCRIPTION OF SYMBOLS 10 Three pole yoke type | mold magnetizer 10a 1st magnetizer 10b 2nd magnetizer 20 Rotating device 21 Motor 22 Rotating shaft 100 Power supply device

Claims (5)

A first magnetizer in which three magnetizing elements each having a wire wound around a yoke are arranged with a phase difference of 120 degrees from each other, and the wires of the three magnetizing elements are Δ-connected or Y-connected; The three magnetized elements wound with a wire are arranged with a phase difference of 120 degrees from each other, and the second magnetizer in which the wires of the three magnetized elements are Δ-connected or Y-connected is placed across the object to be inspected. And place
Applying a three-phase AC voltage to the first magnetizer and the second magnetizer;
An object to be inspected, in which the first magnetizer is fixed, and the magnetic particles are scattered on the object to be inspected while rotating the second magnetizer around the central axis of the three magnetization elements of the second magnetizer. Magnetization method.   2. The method for magnetizing an object to be inspected according to claim 1, wherein the second magnetizer is rotated by 180 degrees or more. A first magnetizer in which three magnetizing elements each having a wire wound around a yoke are arranged with a phase difference of 120 degrees from each other, and the wires of the three magnetizing elements are Δ-connected or Y-connected;
Three magnetizing elements each having an electric wire wound around a yoke are arranged with a phase difference of 120 degrees from each other, and the electric wires of the three magnetizing elements are Δ-connected or Y-connected. A second magnetizer disposed opposite the magnetizer;
A power supply device for applying a three-phase AC voltage to the first magnetizer and the second magnetizer;
A rotating device that rotates the second magnetizer with a driving force of a driving force source ,
The first magnetizer is fixedly supported, the second magnetizer is supported rotatably about a central axis of three magnetizing elements of the first magnetizer, and the rotating device includes at least the Ru is continuously rotating the second magnetizer when spraying the magnetic particles to the object to be inspected, the magnetizing device of the device under test, characterized in that.   4. The magnetizing apparatus for an object to be inspected according to claim 3, wherein the second magnetizer is supported so as to be rotatable by 180 degrees or more. A magnetic particle flaw detector comprising the magnetizing device for an object to be inspected according to claim 3 or 4 .

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