KR101061226B1 - Magnetostrictive transducer module for induction ultrasonic conversion - Google Patents

Abstract

According to the present invention, by removing the ferromagnetic material with a shear coupler during the guided ultrasonic non-destructive inspection, it is easy to install, freely move the inspection point, and reduce the consumption of the ferromagnetic material, which is difficult to recycle, and the entire component. In order to maintain the relative position between the ferromagnetic thin plate, the coil and the bias magnet by making the module into one, the magnetostrictive transducer module for induction ultrasonic conversion can be prevented from changing the sensitivity of the transducer at each inspection. It is about.

The magnetostrictive transducer module for induction ultrasonic conversion according to the present invention has a cylindrical shape case having one side open and a wire connector connecting portion formed at the opposite side of the opening; A coil installed inside the case and configured to generate a magnetic field generated when the induced ultrasonic wave is transmitted or to measure the magnetic field induced when the induced ultrasonic wave is received; Bias magnets installed at both sides of the coil to generate a bias magnetic field so that a static magnetic field is applied to the ferromagnetic material; A yoke having both end portions which are in contact with the bias magnets protruding to one side, and having a support insertion groove formed at the center thereof; An inner supporter having a yoke insertion groove into which the yoke is fitted and supporting the yoke to be stably fixed to the inside of the case; And ferromagnetic thin plates with strong magnetostriction.

Induction Ultrasonic, Transducer, Module, Magnetostriction, Sheet, Magnet, Coil

Description

Magnetostrictive transducer module for induction ultrasonic conversion {magnetostrictive transducer module for generating and measuring guided waves}

The present invention relates to a magnetostrictive transducer module for induction ultrasonic conversion, and in particular, in the non-destructive inspection using induction ultrasonic waves, it is easier to install at an inspection point by not using an adhesive for attachment of a ferromagnetic material. The present invention relates to a magnetostrictive transducer module for induction ultrasonic conversion, which can easily move a point and reduce consumption of ferromagnetic material that is difficult to recycle once attached.

Furthermore, the transducer is modularized into one, so that the relative position between the ferromagnetic thin plate, the coil, and the bias magnet is kept constant, so that the transducer's sensitivity can be prevented from varying during inspection. It is about a module.

Guided ultrasonic waves, which are widely used for non-destructive testing of large structures, are elastic ultrasonic waves that propagate along the boundary of a structure, and can be propagated to a long distance, and thus, they have recently attracted much attention as a method for non-destructive testing of various objects.

Due to such long-range propagation characteristics, the use of guided ultrasonic waves can not only detect a large area at high speed, but also can detect a long distance even when direct access to the inspection site is difficult. On the other hand, the guided ultrasonic wave is difficult to measure and analyze the signal because its type and mode vary according to the shape of the structure and the propagation pattern of each mode is complicated. In particular, transducers, measuring instruments, and signal analysis methods for wave excitation and measurement differ according to the mode and frequency band of the guided ultrasonic wave to be used, the shape and material of the structure, and defects to be detected. Sensitivity to is also affected.

Therefore, it is very important to select an appropriate mode and to select a transducer suitable for the inspection using the guided ultrasonic wave in consideration of the characteristics of the inspection object and the defect. Unlike bulk ultrasonic waves, which are generally divided into longitudinal waves and shear waves, there are various types and modes according to the shape of the waveguide structure.

In the case of a plate-like structure, two types of induced ultrasonic waves may be used, depending on the direction of the displacement of the medium, a lamb wave and a shear horizontal wave (SH), each having an infinite mode.

In the case of a cylindrical structure, there are longitudinal waves, flexural waves, and torsional waves.

Piezoelectric transducers using wedges, piezoelectric transducers with comb-like arrangements, EMAT (electromagnetic acoustic transducers), magnetostrictive transducers for induction ultrasonic conversions ) And the like are used. Of these, the magnetostrictive transducers use the principle of magnetostriction, a phenomenon in which ferromagnetic materials are deformed by a magnetic field, and are very useful for measuring and measuring torsional waves in pipes or axes, as well as lamb or SH waves in plates. As it is efficient, it has been widely applied recently.

Magnetostrictive transducers can be operated in low frequency bands below 100 kHz, and can be used at high temperatures in the case of ferromagnetic materials with high Curie temperatures. In particular, the fact that the structure is simple, excellent in durability, and can be manufactured at a low cost is very noteworthy in consideration of the practical industrial application.

14 illustrates a magnetostrictive transducer using a general ferromagnetic material. A conventional magnetostrictive transducer mainly applies a coil 130 having a magnetic field with a ferromagnetic material 110 having a strong magnetostriction and simultaneously measures the bias. And a bias magnet 120 for generating a magnetic field. In particular, the transducer shown in FIG. 14 is a coil composed of a meander coil, and is an example of a magnetostrictive transducer for induction ultrasonic conversion using a ferromagnetic thin plate as a ferromagnetic material.

In the case of the magnetostrictive transducer configured in this way, since the shear force must be transmitted between the ferromagnetic thin plate and the structure for efficient guided ultrasonic transmission, the ferromagnetic thin plate should be firmly attached to the structure under test using an adhesive such as epoxy.

However, when the ferromagnetic thin plate is attached to the structure using the adhesive, it takes a few minutes to several hours for the adhesive to harden, so it takes a lot of inspection time from attaching the ferromagnetic thin plate to the inspection point to measuring the wave. Once attached ferromagnetic thin plate is difficult to recycle, there is a lot of material consumption, there was a troublesome problem to attach the ferromagnetic thin plate to each point to be examined.

In addition, the relative position between the ferromagnetic thin plate and the coil and the bias magnet is not constant, there was also a problem that the sensitivity of the transducer changes during each inspection.

The present invention was developed to solve the problems of the prior art as described above, an object of the present invention is to provide a magnetostrictive transducer for miniaturized induction ultrasonic conversion by integrating the components of the magnetostrictive transducer in one case. It is done.

That is, the components including the ferromagnetic material, the coil, and the bias magnet are integrated into the case to form a single module, and a shear couplant on a gel is used as a medium between the ferromagnetic material and the inspection object. By using it, it does not consume time to attach the ferromagnetic material to the inspection object, and it not only reduces the inspection time but also does not fix the ferromagnetic material to the structure, so it does not consume a separate ferromagnetic material to measure various points. An object of the present invention is to provide an induction ultrasonic magnetostrictive transducer capable of freely changing a point.

The magnetostrictive transducer module for induction ultrasonic conversion of the present invention is open on one side, and a cylindrical case having a conductive wire connector connected to the opposite side of the opening; A coil installed inside the case and configured to generate a magnetic field generated when the induced ultrasonic wave is transmitted or to measure the magnetic field induced when the induced ultrasonic wave is received; Bias magnets installed at both sides of the coil to generate a bias magnetic field such that a static magnetic field is applied to the ferromagnetic material; A yoke having both end portions which are in contact with the bias magnets protruding to one side, and having a support insertion groove formed at the center thereof; An inner support for forming the yoke insertion groove into which the yoke is fitted and supporting the yoke to be stably fixed to the inside of the case; It is characterized by including a ferromagnetic thin plate having a strong magnetic deformation.

The present invention integrates and modularizes the components of the magnetostrictive transducer in one case so that the relative position between the ferromagnetic thin plate, the coil and the bias magnet is kept constant, thereby preventing the transducer's sensitivity from changing at each inspection. It can work.

In addition, by using a shear couplant on the gel as a medium between the ferromagnetic material and the test object, the time required for attaching the ferromagnetic material to the test object is not consumed. Since it does not adhere to the structure, it does not consume a separate ferromagnetic material for measuring various points, and also has the effect of freely changing the measuring point.

Hereinafter, a magnetostrictive transducer module for induction ultrasound conversion according to the present invention will be described in detail with reference to the accompanying drawings.

First, the magnetostrictive transducer according to the present invention is a technique already known in patent application No. 2009-0027102 filed by the applicant, and modularized the transducer having such a configuration for the purpose as described above.

The overall configuration will be described with reference to FIGS. 1 and 2.

The magnetostrictive transducer module of the present invention has a cylindrical case (1) having one side open and a wire connector connecting portion (11) formed on the opposite side of the opening; A coil (2) installed inside the case (1) and configured to generate a magnetic field having an induced ultrasonic wave transmission or to measure a magnetic field induced upon receiving the ultrasonic wave; Bias magnets (3) installed on both sides of the coil (2) for generating a bias magnetic field so that a static magnetic field is applied to the ferromagnetic material; A yoke (4) having both end portions facing the bias magnets protruding to one side and having a support insertion groove portion (3a) formed at the center thereof; An yoke insertion groove 5a into which the yoke 4 is fitted is formed, and an inner support 5 for supporting the yoke 4 stably in the case; And a ferromagnetic thin plate 6 with strong magnetostriction.

The case 1 has a space formed therein as a means for supporting the components so that the components are stably supported, one side is open, and the wire connector connecting portion 11 is cylindrical on the opposite side of the opening. Formed.

Although the case 1 is configured as a hexahedral shape as an example, it may be configured as a cylindrical shape or a polygonal column shape.

The wire connector connection part 11 is a portion to which the wire connector is connected as described above, and is connected to a BNC connector installed in a conventional magnetostrictive transducer.

Of course, as shown in FIGS. 1 to 5, the wire connector connection part 11 has a wiring hole 11a formed at the center thereof, so that the wire connected to the coil constituting the coil installed therein may pass.

The coil 2, the bias magnet 3, the yoke 4, and the internal support 5 are provided in the case 1.

The coil 2 serves to supply an excitation magnetic field when used as a means for transmitting a signal, that is, an induced ultrasonic wave, and measures a magnetic field derived from a ferromagnetic material when used as a means for receiving an induced ultrasonic wave. .

As shown in FIG. 1, the coil 2 may be formed by winding the conductive wire 22 around the bobbin 21, and a coil wound around the bobbin by forming a groove in a portion where the coil is wound is formed on the surface of the bobbin. Not protruded.

The coil 2 may adjust the frequency by adjusting the spacing of the conductive wires 22 wound on the bobbin 21.

As shown in FIGS. 7 to 9, the bobbin 21 may control the winding interval of the coil by forming various numbers of grooves.

Another example of the coil 2 may be configured as a coil having a meander structure using a PCB fabrication technique, as shown in FIG. 2.

The bias magnet 3 is a means for generating a bias magnetic field. Since the magnetic field must be disposed so as to pass through the ferromagnetic thin plate 6 which is a magnetostrictive body, the bias magnet 3 is composed of permanent magnets and arranged to have opposite polar directions. .

The bias magnets 4 arranged in this way are provided with yokes 4 to reduce the loss of the magnetic field.

Thus, the ferromagnetic thin plate 6-bias magnet 4-yoke 4 form a closed magnetic circuit.

As shown in Fig. 4, the bias magnets 4 are provided at both ends of the yoke 4, respectively.

The bias magnet 3 may be configured of any one of a permanent magnet, an electromagnet or a premagnetization magnet. Premagnetization refers to a method in which a ferromagnetic material is rubbed in one direction with a strong permanent magnet before using the transducer, and then the residual magnetic field remaining in the ferromagnetic material is used as a bias magnetic field.

The yoke 4 is supported inside the case 1 by the inner supporter 5 as one of the means for forming the waste path as described above.

In order to fix the yoke 4 to the inside of the case 1, the inner support 5 and the yoke 4 should be closely coupled, and the inner support 5 should be firmly fixed to the case 1. do.

Accordingly, the support insert insertion groove 4a is formed at the bottom of the yoke 4 to engage the internal support 5, and the support support insertion groove 4a formed at the yoke 4 is formed at the internal support 5. The engaging yoke insertion groove 5a is formed.

In other words, the yoke 4 has a fixed blade 41 is formed on both sides of the support insertion groove 4a so that both side ends of the inner support 5 are sandwiched between the fixed blades 41. And, both ends of the yoke insertion groove (5a) of the inner support (5) is formed with a fixed blade 51 is coupled to each other with both ends of the yoke (4) sandwiched between the fixed blades (51).

The end opposite to the fixing blade 51 of the inner support of the yoke 4 is formed with a blade insertion groove (4b) is coupled in a state where the fixing blade 51 is pinched. The depth of the blade insertion groove 4b is equal to the thickness of the fixed blade 51, the width is equal to the width of the fixed blade.

Fixing blade 51 formed in the inner support (5) is formed longer than the thickness of the yoke, a part of which is inserted into the support fixing groove (1a) formed in the case 1 is supported.

That is, the case 1 is formed with a support fixing hole 1a through which the fixing blade 51 formed in the internal support 5 is inserted and fixed.

The yoke 4 installed inside the case 1 by the inner support 5 has the fixed blades 41 formed on both sides of the yoke 4 on the same plane as the bottom surface of the inner support 5, and the fixed blades 41 The bias magnets (3) are respectively installed in the).

The coil 2 is installed between the bias magnets 3, and the thickness of the bias magnet 3 and the thickness of the coil 2 are the same, so that the two magnets 2 are shown in FIGS. 4 and 5. , Bottom of 3) becomes coplanar.

The ferromagnetic thin plates 6 are installed on the bottoms of the two magnets 2 and 3 thus installed.

The bias magnet 3 should be appropriately disposed in order to apply the static magnetic field flowing along the ferromagnetic thin plate 6 to the ferromagnetic thin plate 6. At this time, the magnetostrictive transducer for SH wave conversion is configured when the coil is arranged perpendicular to the magnetic field direction and the bias magnetic field, and when the magnetomagnetic field direction of the coil is arranged parallel with the bias magnetic field, the magnetostrictive transducer for ram wave conversion is configured.

The magnetostrictive transformer module for induction ultrasonic conversion configured as described above should be brought into close contact with the structure to be inspected so that the deformation of the ferromagnetic thin plate 6 can be well transmitted to the structure. Ferromagnetic thin plate attached to the burned object is difficult to reuse, so the consumption of the ferromagnetic thin plate should be large, so that the structure to be inspected and the ferromagnetic thin plate 6 should be able to be in close contact with each other without using an adhesive.

Therefore, the ferromagnetic thin plate 6 is preferably in close contact with the structure to be tested by a shear couplant on a gel.

The delivery coupler can be selected to use one already developed and provided.

The transducer module configured as described above can convert both lamb wave and SH wave according to the coil and bias magnetic field arrangement.

1 is an exploded perspective view showing an example of a magnetostrictive transducer module for induction ultrasound conversion according to the present invention,

Figure 2 is an exploded perspective view showing another example of the magnetostrictive transducer module for induction ultrasound conversion according to the present invention,

3 is a perspective view of a magnetostrictive transducer module for induction ultrasound conversion according to the present invention;

4 is a cross-sectional view taken along line A-A of FIG.

5 is a cross-sectional view taken along line B-B of FIG.

6 is a perspective view of the state excluding the case,

7 to 9 are perspective views showing different examples of the coil bobbin constituting the magnetostrictive transducer module for induction ultrasonic conversion,

10 is a block diagram of a conventional magnetostrictive transducer for induction ultrasound conversion,

11 is a graph showing the relationship between the frequency of the lamb wave and the group speed,

12 is a graph showing the relationship between the frequency of the SH wave and the group speed.

Description of the Related Art [0002]

1: Case 1a: Support Fixing Groove 11: Conductor Connector Connection Part

  11a: through hole

2: coil 2a: coil winding groove

3: bias magnet

4: yoke 4a: support insertion groove 4b: wing insertion groove

  41: fixed wing

5: internal support 5a: yoke insertion groove 51: fixed blade

6: ferromagnetic lamination

Claims (6)

One side is open, the cylindrical case (1) having a conductive wire connector connecting portion 11 is formed on the opposite side of the opening; A coil (2) installed inside the case (1) and configured to generate a magnetic field having an induced ultrasonic wave transmission or to measure a magnetic field induced upon receiving the ultrasonic wave; Bias magnets (3) installed at both sides of the coil (2) to generate a bias magnetic field so that a static magnetic field is applied to the ferromagnetic material; A yoke (4) having fixed blades (41) formed on both sides of the bias magnets and the support magnets (4a) formed at the center thereof; A yoke insertion groove 5a into which the yoke 4 is inserted is formed, and an inner support 5 supporting the yoke 4 stably in the case; Magnetostrictive transducer module for induction ultrasound conversion, characterized in that it comprises a ferromagnetic thin plate (6) having a strong magnetostriction. The method of claim 1, The case (1) is a magnetostrictive transducer module, characterized in that the support blade fixing hole (1a) is formed through which the fixed blade 51 formed in the inner support (5) penetrated and fixed. The method according to claim 1 or 2, Magnetostrictive transducer module, characterized in that the blade insertion groove (4b) is formed in which the fixed blade 51 is fitted in the part facing the fixed blade 51 formed on the inner support of the yoke (4). The method of claim 3, wherein The bias magnet (3) is an ultrasonic guided magnetostrictive transducer module, characterized in that any one of a permanent magnet, an electromagnet or a premagnetization magnet. The method of claim 4, wherein The coil (2) is a magnetostrictive transducer module for induction ultrasound conversion, characterized in that one of the PCB coil having a periodic solenoid (periodic solenoid) or meander (meander) structure. The method of claim 5, The ferromagnetic thin plate (6) is a magnetostrictive transducer module for induction ultrasound conversion, characterized in that the close contact with the structure to be tested by a shear couplant (gel) on the gel.

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