JP2006194815A - Eddy current flaw detection multi-coil probe and its manufacuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eddy current flaw detection multi-coil probe and its manufacturing method for reducing an increase in a sensitivity fluctuation by reducing a lift-off fluctuation of flaw detection coils, and improving the inspection accuracy. <P>SOLUTION: The eddy current flaw detection multi-coil probe 1 is provided with a plurality of the flaw detection coils having wound conductors, a holding section with a coating layer having a face 10a opposite to an inspected face and bringing the inspected face into contact with a coil holder 10 for accommodating the flaw detection coils in a state to direct end faces of the detection searching coils to the face 10a, and a housing 13 for supporting and relatively moving the coil holder 10 in at least one direction when a temperature changes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an eddy current flaw detection probe used for nondestructive inspection such as inspection at the time of manufacturing steel and non-ferrous materials, maintenance inspection at various plants such as thin tubes of heat exchangers, and maintenance inspection of aircraft, and a manufacturing method thereof.

  The basic principle of flaw detection on a specimen using an eddy current flaw probe is to generate an eddy current on the surface of the specimen to be inspected by an exciting coil and to monitor the change in the detection coil's impedance due to the influence of this eddy current. It is for detecting flaws. That is, if there is a scratch on the surface of the specimen, the scratch has a high effect on the eddy current generated on the surface of the specimen. This change in eddy current also affects the impedance generated in the flaw detection coil. Therefore, the flaw in the test specimen can be detected by monitoring the change in the impedance of the flaw detection coil.

  In order to perform flaw detection efficiently with such an eddy current flaw detection probe, there has been proposed an eddy current flaw detection multi-coil probe in which a plurality of the flaw detection coils described above are arranged in a row in the width direction of a specimen, for example. Yes. According to this eddy current flaw detection multi-coil probe, flaw detection can be performed in a relatively wide range at a time even on the surface of a wide flat specimen.

A configuration of a general eddy current flaw detection multi-coil probe will be described with reference to FIGS. 17 to 21 and Tables 1 to 3. FIG.
Usually, as shown in FIGS. 17 and 18, the eddy current flaw detection multi-coil probe 100 includes a housing 101, a plurality of flaw detection coils 102, a holding unit 105 having a coil holder 103 in which a plurality of flaw detection coils 102 are embedded, and a multiplexer substrate. 106 and a cable 107, and two points between the housing 101 and the holding portion 105 are fastened with screws (not shown) to fix them.
In such a place where the eddy current flaw detection multi-coil probe 100 is used, a temperature change often occurs due to a machine operation or the like, and the temperature of the probe changes. Further, the temperature of the probe changes due to heat generated by the multiplexer substrate 106 and the flaw detection coil 102 built in the probe itself.

  At this time, if the coefficients of thermal expansion of the housing 101 and the coil holder 103 constituting the holding portion 105 are different, the heat of the housing 101 and the holding portion 105 (coil holder 103) is caused as shown in FIG. Elongation is different. Accordingly, since the holding portion 105 (coil holder 103) is fixed to the housing 101, the extension of the holding portion 105 (coil holder 103) is restricted by the housing 101 and receives a compressive load. This load causes the holding portion 105 (coil holder 103) to bend as shown in FIG.

When the holding portion 105 (coil holder 103) is bent, as shown in FIG. 20, the distance between both end portions of the facing surface 103a of the holding portion 105 (coil holder 103) and the inspection target surface T1 is increased. The closer to both ends in the X direction shown in the figure, the wider the distance (hereinafter referred to as lift-off) between the flaw detection coil 102 and the inspection target surface T1.
Here, a simulation result of lift-off of the flaw detection coil 102 and a decrease in flaw detection sensitivity is shown in FIG. 21 (see Table 1 for parameters and conditions used in the calculation). As the lift-off of the flaw detection coil 102 increases, the flaw detection sensitivity decreases.

As described above, when the environmental temperature rises, the holding portion 105 (coil holder 103) bends, and the flaw detection sensitivity decreases as it approaches the both ends of the eddy current flaw detection multi-coil probe 100. In other words, as shown in Table 3, the variation in the flaw detection sensitivity between channels of the eddy current flaw detection multi-coil probe 100 increases as the temperature rises (see Table 2 for calculation conditions), so that flaw detection can be performed accurately. Absent.
In the above description, the sensitivity variation is calculated assuming that the housing material is aluminum.

In order to suppress such sensitivity variation, an eddy current flaw detection multi-coil probe in which a plurality of flaw detection coil patterns are formed on a surface of a flexible film substrate by printed wiring has been proposed (for example, see Patent Document 1). ).
In this probe, a printed circuit board having a flaw detection coil pattern formed on the surface thereof is attached to the probe body. In the case of this configuration, even if there is a temperature change, the flexible coil follows the thermal deformation of the probe, so that bending does not occur, and an increase in flaw detection sensitivity variation due to bending can be suppressed.

Further, there has been proposed an eddy current flaw detection multi-coil probe configured to correct a flaw detection signal of a flaw detection coil based on a distance signal from a distance sensor and eliminate the influence of lift-off (for example, refer to Patent Document 2). .
According to this probe, an increase in flaw detection sensitivity variation due to bending can be suppressed by correcting the signal even if the distance varies.

  However, in the case of the technique described in Patent Document 1, in order to form a flaw detection coil pattern on the surface of the printed circuit board, it corresponds to the surface shape and material to be inspected as compared with a flaw detection coil in which a conducting wire is wound. It is difficult to change the design. In order to form a flaw detection coil pattern on a printed circuit board by etching or the like, it is necessary to create a mold for the pattern every time a design change of the flaw detection coil is performed. There is a problem of increasing.

  Further, when a pattern of a flaw detection coil is formed on a printed circuit board, it is difficult to form a flaw detection coil having high resolution and high sensitivity because the degree of freedom of the coil shape and the number of turns of the coil is small. Furthermore, in the case of a configuration using a printed circuit board, noise may be generated due to the influence of flaw detection coil patterns adjacent to each other.

In the case of the technique described in Patent Document 2, since the distance sensor is provided, there is a problem that the number of members constituting the eddy current flaw detection multi-coil probe is increased and the manufacturing cost is increased.
JP-A-9-33488 JP 2001-56317 A

  The present invention has been made in view of the above circumstances, and an eddy current flaw detection multi-coil probe capable of reducing lift-off variation of a flaw detection coil, suppressing an increase in sensitivity variation, and improving inspection accuracy, and a manufacturing method thereof. The purpose is to provide.

The present invention employs the following means in order to solve the above problems.
The eddy current flaw detection multi-coil probe according to the present invention has a plurality of flaw detection coils formed by winding a conducting wire and a facing surface to the surface to be inspected, with the end surface of the flaw detection coil facing the facing surface. A holding unit having a coil holder for supporting each flaw detection coil, and a housing for supporting the coil holder so as to be relatively movable in at least one direction with respect to the inspection target surface when the temperature changes.

  Also, the method of manufacturing an eddy current flaw detection multi-coil probe according to the present invention includes a plurality of flaw detection coils formed by placing a jig having a base portion and a step portion protruding from the base portion and winding a conducting wire. A step of inserting the plurality of flaw detection coils in a shaft portion erected on the stepped portion so as to be able to be inserted thereinto, and an end surface of the flaw detection coil to the opposite surface having a facing surface to the surface to be inspected. A step of placing the coil holders respectively accommodating the flaw detection coils in a state of being directed on the jig while engaging the concave portion and the stepped portion disposed on the facing surface; and a housing for supporting the coil holder On the other hand, a step of supporting the coil holder on the housing so as to be relatively movable in at least one direction with respect to the surface to be inspected when temperature changes is provided.

  The eddy current flaw detection multi-coil type probe or the eddy current flaw detection multi-coil type probe manufactured by the above-described manufacturing method has a thermal expansion between the coil holder and the housing when the environmental temperature rises or the probe temperature rises due to heat generation of the probe itself. Even if the coefficients are different from each other, the coil holder can be expanded and contracted relatively in at least one direction with respect to the housing and the surface to be inspected. At this time, the coil holder can be supported without generating a compressive force or a tensile force, and the occurrence of deflection of the coil holder can be suppressed and lift-off can be avoided.

Further, the eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the coil holder and the housing in a direction orthogonal to a direction in which the flaw detection coil is scanned with respect to the inspection target surface. A gap is provided between the coil holder and the housing so that the coil holder can move relative to the housing.
This eddy current flaw detection multi-coil probe can expand and contract the coil holder relative to the housing in a direction perpendicular to the scanning direction within a distance corresponding to the gap.

The eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein a substantially central portion of the coil holder is supported with respect to the housing.
In this eddy current flaw detection multi-coil probe, the deformation accompanying the temperature change at the end of the coil holder can be made substantially the same with respect to the housing, and the occurrence of bending of the coil holder can be suitably suppressed.

Further, the eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, and restricts movement of the coil holder in the pressing direction of the elastic member that presses the coil holder. It is characterized by providing the regulation part to perform.
This eddy current flaw detection multi-coil probe is capable of restricting movement in the pressing direction by pressing the coil holder against the restricting portion with an elastic member, and can support the coil holder so as to be movable in a direction orthogonal thereto. .

Further, the eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the restriction portion is disposed on the bottom side of the housing,
The elastic member is arranged in a direction in which the coil holder is pressed against the restricting portion from the opposite side of the opposing surface toward the opposing surface.

  The eddy current flaw detection multi-coil probe can easily position the coil holder with respect to the housing by arranging the coil holder between the restricting portion and the elastic member. Further, by adjusting the elastic force of the elastic member, the force on the coil holder when the coil holder is pressed against the surface to be inspected can be adjusted.

Moreover, the eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the elastic member is closer to the opposed surface side of the coil holder than the restricting portion, and the restricting portion. It arrange | positions in the direction pressed on.
The eddy current flaw detection multi-coil probe can easily position the coil holder with respect to the housing by arranging the coil holder between the restricting portion and the elastic member. At this time, since the pressing direction of the elastic member is the same as the direction in which the coil holder presses the restricting portion when the probe is pressed against the surface to be inspected, the eddy current at the time of flaw detection without increasing the elastic force of the elastic member The rigidity with respect to the pressing direction of the flaw detection multi-coil probe can be increased.

Further, the eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the housing has a first housing and a second housing formed in a substantially L shape, The holding portion is arranged on the inspection target surface side and is formed in a substantially rectangular frame shape.
This eddy current flaw detection multi-coil probe can easily process the housing. Further, the coil holder can be easily positioned with respect to the housing by connecting the first housing and the second housing with the holding portion sandwiched therebetween.

Further, the eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the holding portion is provided with an index portion indicating an arrangement position of the flaw detection coil. To do.
This eddy current flaw detection multi-coil probe can accurately face the inspection object surface within a possible flaw detection range by the flaw detection coil in a state where lift-off is small, and can further improve flaw detection accuracy.

  According to the present invention, it is possible to reduce the lift-off variation of the flaw detection coil, suppress an increase in sensitivity variation, and improve the inspection accuracy.

A first embodiment according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the eddy current flaw detection multi-coil probe 1 according to the present embodiment is connected to a flaw detector main body 2 including a power supply circuit and a control unit (not shown) via a cable 3 so that an inspection target surface T1 is formed. An eddy current flaw detector 5 for flaw detection is configured. The flaw detector main body 2 is provided with various operation switches 6 such as a power switch and a liquid crystal monitor 7 as a display device.

  As shown in FIGS. 2 to 4, the eddy current flaw detection multi-coil probe 1 has a plurality of flaw detection coils 8 formed by winding conductive wires and a facing surface 10a facing the inspection target surface T1, and flaw detection is performed on the facing surface 10a. A holding part 12 having a coil holder 10 that accommodates each of the flaw detection coils 8 in a state where the end face 8a of the coil 8 is directed, and a coating layer 11 that is in contact with the inspection target surface T1, and at least one direction of the coil holder 10 when the temperature changes A housing 13 that is supported so as to be relatively movable, and a multiplexer substrate 15 that performs channel switching of the flaw detection coil 8 are provided.

Each flaw detection coil 8 is a donut type air-core coil, and a conducting wire is wound by, for example, a spindle type automatic winding machine.
Two connectors 15 a and 15 b are arranged on the multiplexer substrate 15.
The flaw detection coil 8 and the multiplexer substrate 15 are connected by a flexible cable 16. One end of the flexible cable 16 is a pattern 16a for connecting coil terminals, and the other end is connected to the multiplexer substrate 15 via a connector 15a.
By connecting the other end of the multiplexer substrate 15 and the cable 3 via the connector 15 b, the flaw detection coil 8 is electrically connected to the cable 3 via the flexible cable 16 and the multiplexer substrate 15.

The coil holder 10 is made of, for example, a resin such as volatilate carbonate, ABS, or boriacetal, and a base portion 10A on which the facing surface 10a is disposed, and a base portion 10A that is spaced from the end of the base portion 10A at a predetermined interval. And a protruding portion 10B protruding in the thickness direction (Z direction) from above.
The coil holder 10 is formed with a plurality of substantially cylindrical housing holes 17 penetrating in the thickness direction (Z direction), and the flaw detection coils 8 are housed in the housing holes 17 respectively. These accommodating holes 17 are, for example, in two rows along the longitudinal direction (X direction) of the coil holder 10 that is orthogonal to the direction (Y direction) of scanning the flaw detection coil 8 with respect to the inspection target surface T1. The accommodation holes 17 in each row are arranged so as to be offset.
Each flaw detection coil 8 is fixed to the coil holder 10 by fixing its peripheral edge to the inner peripheral side of the accommodation hole 17 with an adhesive G.

10 A of base parts are formed so that the dimension of the width direction (Y direction) may become large gradually toward the Z direction upper direction from the opposing surface 10a side. That is, the taper part 18 formed in the taper shape is provided in the edge part of the width direction of the coil holder 10.
The tapered portion 18 is not only formed in a straight line shape, but also, for example, a substantially convex shape that smoothly connects the two side surfaces 10b in the width direction (Y direction) and the opposing surface 10a in the base portion 10A of the coil holder 10. It may be formed in a curved surface shape.

The base portion 10A is provided with an application hole 10c for filling the coating layer 11 during manufacturing and a concave portion 10d having a substantially rectangular shape in cross section formed on the facing surface 10a side. Further, on the side surface 10b, markings (index portions) 20 by groove-like smearing or the like are arranged at the positions where the X direction center portions and the outermost portions of the plurality of flaw detection coils 8 are located.
In addition, mounting holes 10f that can be screwed into the screws 19 are formed in the width direction at substantially the center portions of the two side surfaces 10e in the width direction (Y direction) of the projecting portion 10B of the coil holder 10 respectively. .

  The coating layer 11 is made of an epoxy resin that has substantially the same thermal expansion coefficient as that of the coil holder 10 and has elasticity, and is formed by filling the recess 10 d of the coil holder 10. The surface 11a of the coating layer 11 has the same height as the facing surface 10a of the coil holder 10 and is disposed so as to face the inspection target surface T1.

The housing 13 has a size that allows the housing 13 to be placed on the base portion 10A with the protruding portion 10B of the coil holder 10 inserted therein. At this time, the length between the inner wall surfaces 13a in the longitudinal direction of the housing 13 is such that gaps 13A having the same interval are arranged between the respective end surfaces 10g in the longitudinal direction of the protruding portion 10B of the coil holder 10 and the inner wall surface 13a of the housing 13. As described above, the coil holder 10 is formed to be longer than the length between the end faces 10g of the protruding portion 10B.
This gap 13A is determined in consideration of the thermal expansion between the housing 13 and the coil holder 10, for example, when the material of the housing 13 is aluminum, the material of the coil holder 10 is polycarbonate, and the length of the coil holder 10 in the X direction is 200 mm. The gap 13A is 0.3 mm or more.

  The housing 13 is located on the lower end surface 13b side of the housing 13 from the upper end surface 10i side of the projecting portion 10B of the coil holder 10 at a position facing the mounting hole 10f disposed on the side surface 10e of the projecting portion 10B of the coil holder 10. A through hole 13c through which the screw 19 can pass when placed on the placement surface 10j on the base 10A is arranged. That is, when the coil holder 10 and the housing 13 are fixed with the screws 19, the coil holder 10 is supported so as to be expandable and contractable in the longitudinal direction with respect to the housing 13 when the temperature rises.

The housing 13 includes a first housing 21, a second housing 22, and a housing lid 23. The first housing 21 is formed in an approximately L shape, and a U-shaped notch 21 a for inserting the cable 3 and a pedestal 21 b for attaching the multiplexer substrate 15 are arranged on the side surface. A cable ground cover 25 that fixes and covers the cable 3 is disposed in the notch 21 a of the first housing 21.
A cable gland 26 is attached to the cable gland cover 25. The assembly of the cable 3 is preferably performed in a state where the cable 3 is inserted into the cable ground cover 25 and the cable ground 26.

The second housing 22 is configured in a substantially L shape that is substantially symmetrical with the first housing 21.
That is, the housing 13 is formed in a substantially rectangular frame shape by combining the first housing 21 and the second housing 22 and arranging the holding portion 12 on the inspection target surface T1 side.
It is preferable that a waterproof seal such as an O-ring (not shown) is disposed at each joint of the first housing 21, the second housing 22, the housing lid 23, and the holding portion 12 to form a drip-proof structure.

Next, a method for manufacturing the eddy current flaw detection multi-coil probe 1 according to the present invention will be described.
In this manufacturing method, a jig 30 having a base part 27 and a step part 28 protruding from the base part 27 is placed, and the step part is inserted into a plurality of flaw detection coils 8 formed by winding a conducting wire. The step (S01) of inserting the plurality of flaw detection coils 8 into the positioning pins (shaft portions) 31 erected on 28 and the coil holder 10 while engaging the recess 10d and the stepped portion 28 of the jig 30 A step of placing on the jig 30 (S02), a step of fixing the flaw detection coil 8 to the coil holder 10 (S03), a step of removing the coil holder 10 from the jig 30 and filling the recess 10d with the coating layer 11 ( S04) and a step (S05) of supporting the coil holder 10 relative to the housing 13 so as to be relatively movable in the longitudinal direction (X direction) when the temperature changes.

  First, before the insertion step (S01) of the flaw detection coil 8, the coil holder 10 having the accommodation hole 17, the concave portion 10d, and the taper portion 18 is previously formed so that the inner diameter of the accommodation hole 17 is larger than the outer dimension of the flaw detection coil 8. To form.

  In the insertion step (S01) of the flaw detection coil 8, first, the flaw detection coil 8 is placed on the jig 30 as shown in FIG.

  The positioning pins 31 further protrude from the mounting surface 28a of the step portion 28, and are arranged in two rows along the longitudinal direction (X direction) as in the case of the receiving hole 17 of the coil holder 10 described above, and the positioning pins in each row. 27 is arranged at an offset position. The outer diameter of the positioning pin 31 is slightly smaller than the inner diameter of the flaw detection coil 8. That is, for example, when the inner diameter of the flaw detection coil 8 is 1.08 mm, the outer diameter of the positioning pin 31 is 1.06 mm.

The flaw detection coils 8 are attached to the plurality of positioning pins 31, respectively. At this time, since the positioning pins 31 are offset from each other, the flaw detection coils 8 are attached to the respective positioning pins 31 so that the adjacent flaw detection coils 8 are held at equal intervals.
When mounting the flaw detection coil 8, the end surface 8 a of the flaw detection coil 8 is mounted so as to contact the mounting surface 28 a of the stepped portion 28. As a result, the positions of the flaw detection coils 8 in the Z direction are aligned.

Next, the process proceeds to the step of placing the coil holder 10 on the jig 30 (S02).
A flat surface 27a for placing the opposing surface 10a of the coil holder 10 is disposed on the base portion 27 of the jig 30, and a mounting surface 28a that can be engaged with the recess 10d of the coil holder 10 is disposed on the step portion 28. Has been.
The coil holder 10 is cured so that the bottom surface of the recess 10d of the coil holder 10 is in contact with the mounting surface 28a of the stepped portion 28 and the opposing surface 10a of the coil holder 10 is in contact with the flat surface 27a of the base portion 27. Place on tool 30. Thus, when the recess 10 d of the coil holder 10 and the stepped portion 28 are fitted, the flaw detection coil 8 is accommodated in each accommodation hole 17. In this state, since the flaw detection coil 8 and the coil holder 10 are both fixed to the jig 30, the relative positions of the flaw detection coil 8 and the coil holder 10 are determined.

And it transfers to the process (S03) which fixes the flaw detection coil 8 to the coil holder 10. FIG.
Here, each flaw detection coil 8 and the coil holder 10 are fixed by the adhesive G. Examples of the adhesive G used here include UV adhesives (World Lock 8463 (Kyoritsu), World Rock 8403 (Kyoritsu), World Rock 8130 (Kyoritsu), World Rock 8840 (Kyoto), 836TNS ( (Cooperative), 326 UVBLUE (Loctite)), instantaneous adhesive (Aron α (cemedine)) epoxy adhesive, urethane adhesive, silicon adhesive and the like.
At the time of bonding, it is preferable that each flaw detection coil 8 is pressed against the mounting surface 28 a and the facing surface 10 a of the coil holder 10 is pressed against the flat surface 27 a of the base portion 27. Thereby, the positions of the end faces 8a of the plurality of flaw detection coils 8 can be reliably aligned in the Z direction.
In this manufacturing, the flaw detection coil 8 may be attached to the positioning pin 31 after the coil holder 10 is placed on the jig 30.

Next, the process proceeds to the step of filling the coating layer 11 (S04).
Here, first, the coil holder 10 is removed from the jig 30 and the coil holder 10 is fixed so that the facing surface 10a of the coil holder 10 to which the flaw detection coil 8 is fixed contacts the surface 32a of the coating layer jig 32 as shown in FIG. The holder 10 is placed. Then, an epoxy resin as a material of the coating layer 11 is applied from each of the application hole 10c, the accommodation hole 17, and the flaw detection coil 8 of the coil holder 10 so as to fill the recess 10d.

Examples of the epoxy resin used at this time include a two-part epoxy adhesive (main agent: TB2024 and curing agent: TB2131D (three bond), main agent: TB2023 and curing agent: TB2103 (three bond)), or main agent: TB2023 and curing agent. : TB2131D (Three Bond)). In this case, a resin having a thermal expansion coefficient close to that of the material of the coil holder 10 (polycarbonate in the present embodiment) is preferable. A material having wear properties is preferred.
Here, it is preferable to cure the filled epoxy resin while pressing the coil holder 10 against the mounting surface 28a. Thereby, the plane of the coating layer 11 can be smoothly created in the Z direction. Further, by applying a release agent on the surface 32a of the coating layer jig 32, the peeling of the holding portion 12 on which the jig 30 and the coating layer 11 are arranged can be improved, and the coating layer 11 can be made smooth. it can. Moreover, the coating layer 11 without a bubble can be created by performing a defoaming process (vacuum defoaming etc.) at the time of hardening of the coating layer 11.

After removing the holding part 12 to which the flaw detection coil 8 and the coating layer 11 are attached from the coating layer jig 32, the process proceeds to the step of supporting the coil holder 10 on the housing 13 (S05).
First, the flexible cable 16 and the end of the flaw detection coil 8 are connected by solder or the like. At the same time, the flexible cable 16 is fixed to the holding portion 12 by bonding or the like. Next, the cable 5 is attached to the multiplexer substrate 15, and the end portion of the flexible cable 16 is attached to the connector 15 a of the multiplexer substrate 15.

  And while attaching the multiplexer board | substrate 15 to the 1st housing 21, the 1st housing 21 and the 2nd housing 22 are mounted on 10 A of base parts of the coil holder 10, inserting the protrusion part 10B of the coil holder 10 inside. At this time, as shown in FIG. 7, the positions of the mounting holes 10f arranged on the side surface 10e of the projecting portion 10B of the coil holder 10 and the through holes 13c arranged in the housing 13 are made to coincide with each other. Is screwed into the mounting hole 10f to fix the coil holder 10 and the housing 13, and the cable ground cover 25 and the housing lid 23 are attached to complete the assembly.

  When the flaw detection multi-coil probe 1 detects flaws on the inspection target surface, as shown in FIG. 4, the inspection target surface T <b> 1, the facing surface 10 a of the coil holder 10, and the surface 11 a of the coating layer 11. The eddy current flaw detection multi-coil probe 1 is moved in the width direction (Y direction) of the coil holder 10 with the entire surface 12a of the holding portion 12 made of

When the probe temperature rises due to an increase in the environmental temperature or due to the heat generated by the probe itself, the housing 13 and the coil holder 10 have different thermal expansion coefficients, resulting in different elongations. In this embodiment, since the coefficient of thermal expansion of the coil holder 10 is larger, the coil holder 10 is relatively extended.
At this time, the coil holder 10 is fixedly held to the housing 13 by the screw 19 at a substantially central portion of the side surface 10e of the projecting portion 10B of the coil holder 10, and the longitudinal inner wall surface 13a of the housing 13 and the coil holder 10 are fixed. A gap 13 </ b> A from the end portion 10 g of the coil holder 10 is set to be larger than the relative elongation of the coil holder 10 with respect to the housing 13.

  Therefore, according to the eddy current flaw detection multi-coil probe 1, as shown in FIG. 3, even if the coil holder 10 extends relatively in the direction of the end 10g around the mounting hole 10f, the end of the coil holder 10 Interference between 10 g and the inner wall surface 13 a of the housing 13 can be suppressed. Then, without generating a compressive load on the coil holder 10, it is possible to suppress the occurrence of bending and suppress the occurrence of lift-off caused by the bending.

  Further, since the central portion of the coil holder 10 is fixed by the screw 19 so that the gap 13A is substantially the same, the deformation accompanying the temperature change at the end portion 10g of the coil holder 10 is substantially the same as that of the housing 13. Therefore, the occurrence of bending of the coil holder 10 can be more suitably suppressed.

  Further, since the coating layer 11 is arranged on the facing surface 10a side, when the holding unit 12 is moved in a state where the coating layer 11 is in contact with the inspection target surface T1, the end surface of the flaw detection coil 8 is detected when a scratch is detected. 8a can be prevented from coming into direct contact with the inspection target surface T1, and the flaw detection coil 8 can be protected.

  Further, even if an obstacle such as a protrusion protruding from the inspection target surface T1 exists ahead of the moving direction of the eddy current flaw detection multi-coil probe 1, the taper portion 18 smoothly guides the entire surface 12a of the holding portion 12. Therefore, the holding part 12 can be smoothly moved with respect to the inspection target surface T1 regardless of the presence or absence of an obstacle.

Further, the coil holder 10 can be easily positioned with respect to the housing 13 by connecting the first housing 21 and the second housing 22 with the holding portion 12 interposed therebetween. And since the 1st housing 21 and the 2nd housing 22 are each processed and assembled, housing processing can be performed more easily than the case where it processes integrally.
In addition, since the marking 20 is arranged, the inspection target surface T1 can be accurately arranged within a possible flaw detection range by the flaw detection coil 8 with little lift-off, and the flaw detection accuracy can be further improved.

Next, a second embodiment will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above, and description is abbreviate | omitted.
The difference between the second embodiment and the first embodiment is that the eddy current flaw detection multi-coil probe 40 according to this embodiment includes a spring member (elastic member) 44 that presses the coil holder 43, and a spring member 44. This is that a holder guide 45 having a later-described flange portion (regulator portion) 46 that restricts the movement of the coil holder 43 in the pressing direction is provided.

Unlike the coil holder 10 according to the first embodiment, the coil holder 43 protrudes in the width direction (Y direction) from the base portion 43A on which the facing surface 43a is arranged instead of the protruding portion 10B, and is substantially the same as the facing surface 43a. A support portion 43B having parallel locking surfaces 43k is provided.
A plurality of accommodation holes 17 are arranged through the support portion 43B and the base portion 43A in the thickness direction (Z direction), and the flaw detection coils 8 are accommodated in the accommodation holes 17, respectively.

  The holder guide 45 is formed in a substantially rectangular frame shape, and can be connected to the inside on the lower end surface 41 b side, which is the bottom portion of the housing 41, with screws 19. On the inner surface on the lower end surface 45a side of the holder guide 45, a flange portion 46 formed with a contact surface 46a that contacts the locking surface 43k of the support portion 43B is provided so as to protrude inward. The protruding height of the flange portion 46 is set to a length that can penetrate the base portion 43A of the coil holder 43 and can lock the locking surface 43k of the support portion 43B to the contact surface 46a of the flange portion 46. .

The length between the inner wall surfaces 45b in the longitudinal direction of the holder guide 45 is such that a gap 45A of the same interval is arranged between each end surface 43g in the longitudinal direction of the coil holder 43 and the inner wall surface 45b of the holder guide 45. The coil holder 43 is formed longer than the length between the end faces 43g in the longitudinal direction.
Similar to the gap 13A according to the first embodiment, the gap 45A is determined in consideration of the thermal expansion between the holder guide 45 and the coil holder 43, and is formed so as to be substantially equidistant in the longitudinal direction.
On the side surface 45c in the width direction (Y direction) of the holder guide 45, an attachment hole 45d that can be screwed with the screw 19 is disposed.

The spring member 44 is formed in a plate spring shape, and is disposed at, for example, four locations on the upper end surface 45 e of the holder guide 45 that is the bottom side of the housing 41.
The spring member 44 attaches the coil holder 43 to the opposite side of the facing surface 43a, that is, in the direction of pressing the flange 46 of the holder guide 45 from the upper side in the thickness direction (Z direction) of the coil holder 43 toward the facing surface 43a. It is energized.

  According to the eddy current flaw detection multi-coil probe 40, the coil holder 43 is pressed against the holder guide 45 by the spring member 44, thereby restricting the movement of the coil holder 43 in the pressing direction (Z direction) relative to the housing 41. Since the inner wall surface of 45 and the outer wall surface of the coil holder 43 are fitted in the width direction (Y direction), the movement of the coil holder 43 in the width direction relative to the housing 41 is restricted. While the holder 43 can be easily positioned, in the longitudinal direction (X direction), the coil holder 43 is relative to the holder guide 45 within the gap 45A in the same manner as in the first embodiment. Can be movably supported.

  Moreover, since it supports by the spring member 44, a hole and a tap process are unnecessary for the coil holder 43, and the coil holder 43 can be manufactured cheaply. Further, by adjusting the elastic force of the spring member 44, the force on the coil holder 43 when the coil holder 43 is pressed against the inspection target surface T1 can be adjusted.

Next, a third embodiment will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected to the component similar to other embodiment mentioned above, and description is abbreviate | omitted.
The difference between the third embodiment and the other embodiments described above is that the side surface in the width direction (Y direction) of the protruding portion 52B of the coil holder 52 related to the holding portion 51 of the eddy current flaw detection multi-coil probe 50 according to this embodiment. A recess 53 is formed in 52 e, and a recess upper surface 53 a in the same direction as the facing surface 52 a of the coil holder 52 is disposed in the recess 53.

The thickness of the side surface 55d in the width direction (Y direction) of the housing 55 is formed to protrude thicker on the upper end surface 55e side than on the lower end surface 55b side, and a stepped portion (regulating portion) 56 is formed at the boundary portion. Is arranged.
The stepped portion 56 is provided with a contact surface 56 a that can come into contact with the upper end surface 52 i of the coil holder 52 when the housing 55 is placed on the base portion 52 </ b> A of the coil holder 52. The height of the stepped portion 56 is a protruding height at which the coil holder 52 is locked and positioned.
A gap (not shown) similar to that in the first embodiment is disposed between the side surface 52g in the longitudinal direction (X direction) of the protrusion 52B of the coil holder 52 and the inner wall surface 55a in the longitudinal direction of the housing 55. .

  The spring member 57 is disposed on the inner side of the lower end surface 55b side of the housing 55 such that the contact surface 56a of the stepped portion 56 is urged so that the upper end surface 52i of the coil holder 52 can be pressed from the opposing surface 52a side. .

According to this eddy current flaw detection multi-coil probe 50, the same operation and effect as in the other embodiments can be obtained.
In particular, the coil holder 52 can be easily positioned with respect to the housing 55 by arranging the coil holder 52 between the step portion 56 and the spring member 57. At this time, since the pressing direction of the spring member 57 is the same as the direction in which the coil holder 52 presses the stepped portion 56 when the probe is pressed against the inspection target surface T1, the elastic force of the spring member 57 is increased. The rigidity in the pressing direction of the eddy current flaw detection multi-coil probe 50 can be further increased.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the accommodation hole 17 is formed in a substantially cylindrical shape. However, the present invention is not limited to this. For example, as shown in FIG. A taper portion 61 that gradually increases in diameter from the facing surface 60a side disposed on 60A toward the upper end surface 60i side of the protruding portion 60B may be formed. When configured in this way, the adhesive G easily flows along the tapered portion 61, so that the adhesive G can surely reach the flaw detection coil 8, and the flaw detection coil 8 easily enters the accommodation hole 17 of the coil holder 60. In addition, it can be securely fixed.

  The coating layer 11 is filled in the recess 10d of the coil holder 10 or 43 or 52. However, the coating layer 11 is not limited to this, and is pre-coated with, for example, epoxy resin, silicon resin, urethane resin, or Teflon (registered trademark) resin. A layer may be prepared and bonded to the recess 10e of the coil holder 10.

  Further, although each flaw detection coil 8 is fixed to the coil holder 10 by the adhesive G, the present invention is not limited to this, and a silicon resin is used so that the flaw detection coil 8 is buried in the accommodation hole 17 as shown in FIG. Alternatively, the holding portion 63 in which the receiving hole 17 is filled with a filler 62 such as urethane resin or Teflon (registered trademark) resin and the flaw detection coil 8 is fixed to the coil holder 10 may be used. In the case of this configuration, the coating layer 11 may be formed at the same time that the flaw detection coil 8 is buried in the accommodation hole 17.

  Further, although the cable 3 is fixed to the housing 13, it can be detachable via a connector (not shown).

Further, in the first embodiment, the connection between the housing 13 and the coil holder 10 is tightened with the screw 19, but a tap is cut on the housing side, a hole is made on the coil holder side, and the tip is a pin-shaped nose. An attached screw may be arranged and fixed to the housing. At this time, a bottle or a key may be press-fitted or adhesively fixed to the housing.
In this case, in addition to the effects according to the first embodiment, the screw fixing or the pin or key is press-fitted or adhesively fixed on the housing side as compared with the screw tightening with the coil holder, so that it can be fixed more strongly and positioned. The accuracy can be increased.

Moreover, in the said 2nd Embodiment, although the spring member 44 is distribute | arranged to the upper end surface 45e of the holder guide 45, as shown in FIG. 12, the width direction (Y direction) side surface of the housing 65 is shown. The eddy current flaw detection multi-coil probe 66 may be provided with a spring member 44 so as to be biased in the same direction as 65e.
Also in this case, the same operations and effects as those of the second embodiment can be achieved.

In addition, as in the second and third embodiments, the spring member 44 does not position the coil holder 43 relative to the holder guide 45 or the coil holder 52 relative to the housing 55. As shown in FIG. 13, a recess 71 is provided in the substantially central portion in the longitudinal direction of the coil holder 70, and a pin 73 inserted in a through hole 72 a disposed in the substantially central portion in the longitudinal direction of the holder guide 72 is inserted into the recess 71. Depending on the situation, positioning may be performed.
Further, as shown in FIG. 14, the convex portion 76 provided at the substantially central portion in the longitudinal direction of the holder guide 75 is fitted into the concave portion 71 of the coil holder 70, thereby positioning the coil holder 70 with respect to the holder guide 75. May be.

Further, as shown in FIG. 15, a hole 80 a provided in a substantially central portion in the longitudinal direction of the coil holder 81 is provided on a pin 80 erected in a substantially central portion in the longitudinal direction of the flange portion 78 in the longitudinal direction of the holder guide 77. The coil holder 81 may be positioned with respect to the holder guide 77 by fitting into the long hole 81b.
In any of these cases, when the temperature rises, the coil holder can be expanded and contracted with respect to each holder guide from the central portion in the longitudinal direction to the end portion, and the same operations and effects as the above embodiments can be achieved. be able to.

In addition, as shown in FIG. 16, when the inspection target surface T2 is a curved surface such as the outside of the pipe 82, the shape of the holding portion 83, the concave portion 86 of the coil holder 85, and the shape of the housing 87 are determined. A curved surface may be used in accordance with the shape of the surface T2.
In this case, the surface 88a of the coating layer 88 is also a curved surface, whereby the eddy current flaw detection multi-coil probe 90 and the inspection target surface T2 can be more closely attached. Further, the surface is not limited to a curved surface, and may be an uneven surface according to the shape of the surface to be inspected, or a surface in which a flat surface and a curved surface are combined.

It is a perspective view which shows an eddy current test equipment value provided with the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. It is a disassembled perspective view which shows the structure of the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. 1 is a cross-sectional view of an eddy current flaw detection multi-coil probe according to a first embodiment of the present invention. It is sectional drawing of the holding | maintenance part of the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the (a) manufacturing method of the eddy current test multicoil type probe which concerns on the 1st Embodiment of this invention, (b) It is sectional drawing which shows the middle of the assembly of a holding | maintenance part. It is explanatory drawing which shows the (a) manufacturing method of the eddy current test multicoil type probe which concerns on the 1st Embodiment of this invention, (b) It is sectional drawing which shows the middle of the assembly of a holding | maintenance part. It is explanatory drawing which shows the structure and manufacturing method of the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. (A) Explanatory drawing which shows the structure and manufacturing method of the eddy current flaw detection multi-coil type probe concerning the 2nd Embodiment of this invention, (b) X direction sectional drawing which shows a holding part, (c) Y direction which shows a holding part It is sectional drawing. It is explanatory drawing which shows the (a) structure and manufacturing method of the eddy current test multi-coil type probe which concerns on the 3rd Embodiment of this invention, (b) It is sectional drawing which shows a holding part. It is sectional drawing which shows the modification of the holding | maintenance part of the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the modification of the holding | maintenance part of the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the (a) structure and manufacturing method in the modification of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention, (b) X direction sectional drawing. It is a perspective view of the holding | maintenance part which shows the modification of the eddy current test multi coil type probe which concerns on the 2nd Embodiment of this invention. It is a perspective view of the holding | maintenance part which shows the modification of the eddy current test multi coil type probe which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the assembly process of the holding | maintenance part which shows the modification of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the modification of the eddy current test multi coil type probe which concerns on the 3rd Embodiment of this invention. It is a disassembled perspective view which shows the structure of the conventional eddy current test multi-coil type probe. It is sectional drawing which shows the conventional eddy current test multi-coil type | mold probe. It is (a) decomposition | disassembly block diagram of the conventional eddy current test multi-coil type probe, (b) It is explanatory drawing which shows a bending state. It is explanatory drawing which shows the bending state of this invention and the conventional eddy current test multi-coil type | mold probe. It is a graph which shows the relationship between a lift-off and a sensitivity fall amount.

Explanation of symbols

1, 40, 50, 66, 90, 100 Eddy current flaw detection multi-coil probe 8, 102 Flaw detection coil 8a End face 10, 103, 43, 52, 60, 70, 81, 85 Coil holder 10a, 42a, 52a, 60a, 103a Opposing surface 10d Recesses 12, 42, 51, 63, 83 Holding parts 13, 41, 65, 87 Housings 13A, 45A Clearance 20 Marking (index part)
21 First housing 22 Second housing 27 Base portion 28 Step portion 30 Jig 31 Positioning pin (shaft portion)
44, 57 Spring member (elastic member)
46 Buttocks (Regulation Department)
T1, T2 Inspection target surface

Claims (9)

A plurality of flaw detection coils formed by winding conductive wires;
A holding portion having a coil holder for supporting the flaw detection coil in a state where the flaw detection coil has an opposing surface to the inspection target surface and the end surface of the flaw detection coil faces the opposing surface;
A eddy current flaw detection multi-coil probe comprising a housing that supports the coil holder so as to be relatively movable in at least one direction with respect to the surface to be inspected when temperature changes.   A gap is provided between the coil holder and the housing in a direction orthogonal to the direction in which the flaw detection coil is scanned with respect to the inspection target surface, so that the coil holder can move relative to the housing. The eddy current flaw detection multi-coil probe according to claim 1.   The eddy current flaw detection multi-coil probe according to claim 1, wherein a substantially central portion of the coil holder is supported with respect to the housing. An elastic member for pressing the coil holder;
3. The eddy current flaw detection multi-coil probe according to claim 1, further comprising a restricting portion that restricts movement of the coil holder in a pressing direction of the elastic member. The restricting portion is disposed on the bottom side of the housing;
5. The eddy current flaw detection multi-coil probe according to claim 4, wherein the elastic member is disposed in a direction in which the coil holder is pressed against the restriction portion from the opposite side of the facing surface toward the facing surface. .   The eddy current flaw detection multi-coil system according to claim 4, wherein the elastic member is disposed closer to the opposed surface side of the coil holder than the restricting portion and in a direction in which the elastic member is pressed against the restricting portion. probe.   The housing includes a first housing and a second housing formed in a substantially L shape, and is formed in a substantially rectangular frame shape with the holding portion disposed on the inspection target surface side. The eddy current flaw detection multi-coil probe according to any one of claims 1 to 6.   2. The eddy current flaw detection multi-coil probe according to claim 1, wherein the holding portion is provided with an index portion that indicates an arrangement position of the flaw detection coil. A shaft having a base portion and a step portion protruding from the base portion is placed on a shaft portion erected on the step portion so as to be inserted into a plurality of flaw detection coils each formed by winding a conducting wire. Inserting the plurality of flaw detection coils;
A coil holder that accommodates each of the flaw detection coils in a state having an opposed surface to the inspection target surface and facing an end surface of the flaw detection coil to the opposed surface, and a recess disposed on the opposed surface and the stepped portion. Placing on the jig while engaging;
And a step of supporting the coil holder on the housing so as to be relatively movable in at least one direction with respect to the surface to be inspected when the temperature changes with respect to the housing supporting the coil holder. Manufacturing method of flaw detection multi-coil probe.

Images