JP2006189364A - Eddy current flaw detection multi-coil type probe, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eddy current flaw detection multi-coil type probe capable of narrowing lift-off dispersion of a flaw detection coil to restrain dispersion of sensitivity from increasing, and capable of enhancing inspection precision, and provide a manufacturing method therefor. <P>SOLUTION: This probe includes a holding part 12 having the plurality of flaw detection coils 8 wound with a conductor wire, a coil holder 10 having an opposed face 10a to an inspection objective face T1 and for supporting the flaw detection coils 8 respectively under the condition where an end face of each of the flaw detection coils 8 is directed to the opposed face 10a, and a coating layer 11 contacting with the inspection objective face T1; and a housing 13 for supporting the holding part 12. The coil holder 10 comprises a resin filled with 20% of inorganic filler (glassy member), for example, such as glass fiber, in a base resin comprising a thermoplastic resin, for example, a polycarbonate. A thermal expansion coefficient of the polycarbonate filled with 20% of the glass fiber is brought into a value substantially same to a thermal expansion coefficient of aluminum that is a material of the housing 13. <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.

The configuration of a general eddy current flaw detection multi-coil probe will be described with reference to FIGS. 20 to 24 and Tables 1 to 3. FIG.
Usually, as shown in FIGS. 20 and 21, an 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 four 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 unit 105 are different, the heat of the housing 101 and the holding unit 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. Due to this load, the holding portion 105 (coil holder 103) bends as shown in FIG.

When the holding portion 105 (coil holder 103) is bent, as shown in FIG. 23, the both ends of the facing surface 103a of the holding portion 105 (coil holder 103) facing the inspection target surface T1 and the inspection target surface T1. As a result, the distance increases, and as a result, the distance between the flaw detection coil 102 and the inspection target surface T1 (hereinafter referred to as lift-off) increases as the distance from both ends in the X direction shown in the drawing increases.
Here, a simulation result of lift-off of the flaw detection coil 102 and a decrease in flaw detection sensitivity is shown in FIG. 24 (see Table 1 for parameters and conditions used in the calculation). Thus, the flaw detection sensitivity decreases as the lift-off of the flaw detection coil 102 increases.

As described above, when the probe temperature rises, the holding unit 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.

  In order to solve the above-described problems, an eddy current flaw detection multi-coil probe according to the present invention has a plurality of flaw detection coils formed by winding conducting wires and a facing surface to a surface to be inspected. A holding part having a coil holder for supporting each of the flaw detection coils in a state where the end face is directed, and a housing for supporting the holding part, and the coefficient of thermal expansion of the coil holder and the coefficient of thermal expansion of the housing are: It is characterized by being substantially identical.

  This eddy current flaw detection multi-coil probe has the same temperature change between the coil holder and the housing even when the ambient temperature rises or the probe temperature rises due to the heat generated by the probe itself. Can be suppressed.

An 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 is made of a resin having an inorganic filler.
This eddy current flaw detection multi-coil probe can obtain a coil holder having substantially the same thermal expansion coefficient as that of the housing, depending on the type of resin as a base and the type and amount of inorganic filler added to the resin.

The eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the resin is a thermoplastic resin and the inorganic filler is a glass member. .
This eddy current flaw detection multi-coil probe can easily obtain a suitable thermal expansion coefficient.

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 resin is an epoxy resin whose thermal expansion coefficient can be changed depending on the filling amount of the inorganic filler. It is characterized by that.
This eddy current flaw detection multi-coil probe can obtain a coil holder having substantially the same thermal expansion coefficient as that of the housing in accordance with the filling amount of the inorganic filler added to the base resin.

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 includes a coil substrate electrically connected to each of the flaw detection coils, A flaw detection coil is supported by the coil holder via the coil substrate, and the thermal expansion coefficient of the coil substrate and the thermal expansion coefficient of the coil holder are substantially the same.
This eddy current flaw detection multi-coil probe can further improve workability by supporting the flaw detection coil on the coil substrate.

  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 is formed in a frame shape and at least partially filled with an elastic filler, The flaw detection coil is supported by the coil holder via the filler.

  In this eddy current flaw detection multi-coil type probe, if the temperature of the probe rises due to an increase in the environmental temperature or due to the heat generated by the probe itself, even if there is a difference in the amount of thermal deformation between the coil holder and the housing, By doing so, the deformation amount can be absorbed. In addition, when manufacturing other types of eddy current flaw detection multi-coil probes having different arrangements and shapes of flaw detection coils, the coil holder can be used and the manufacturing cost can be reduced.

The eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the filler is a foamed resin.
This eddy current flaw detection multi-coil probe can absorb the amount of thermal deformation more suitably.

  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 includes a coating layer in contact with the inspection target surface, and the thermal expansion coefficient of the coating layer and the The coefficient of thermal expansion of the coil holder is substantially the same.

  This eddy current flaw detection multi-coil probe can suitably suppress the bending of the coating layer or the coil holder with respect to the housing even when the environmental temperature rises or the probe temperature rises due to heat generation of the probe itself.

The eddy current flaw detection multi-coil probe according to the present invention is the eddy current flaw detection multi-coil probe, wherein the coating layer has elasticity.
This eddy current flaw detection multi-coil probe can absorb the deformation amount by elastic deformation of the coating layer even if a difference in thermal deformation amount occurs between the coil holder and the housing. In addition, when manufacturing other types of eddy current flaw detection multi-coil probes having different arrangements and shapes of flaw detection coils, the coil holder can be used and the manufacturing cost can be reduced.

  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 position the coil holder with respect to the housing by connecting the first housing and the second housing with the holding portion interposed 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.
In this eddy current flaw detection multi-coil probe, the surface to be inspected can be accurately arranged within a possible flaw detection range with a flaw detection coil with little lift-off, and the flaw detection accuracy can be further improved.

  A manufacturing method of an eddy current flaw detection multi-coil probe according to the present invention is a coil holder comprising a housing hole for supporting a plurality of flaw detection coils formed by winding a conducting wire, and a recess filled with a coating layer in contact with a surface to be inspected. And a second base portion in which a through-hole through which the shaft portion can pass is disposed on a first base portion in which a shaft portion that can be inserted into each of the plurality of flaw detection coils is erected. A step of inserting the shaft holder through the hole and placing the coil holder on the second base portion; a step of inserting the plurality of flaw detection coils into the shaft portion; and the flaw detection coil as the coil A step of fixing to the holder, a step of removing the coil holder from the second base portion and filling the recess with the coating layer, and a housing portion having substantially the same thermal expansion coefficient as the coil holder. Characterized in that it comprises the step of attaching the coil holder.

  This eddy current flaw detection multi-coil probe is manufactured by attaching the coil holder to a housing part having the same thermal expansion coefficient as that of the coil holder, so that the probe temperature rises due to an increase in environmental temperature or due to heat generation of the probe itself. However, substantially the same length change can be produced between the coil holder and the housing, and the bending of the coil holder can be suppressed.

  Also, in the manufacturing method of the eddy current flaw detection multi-coil probe according to the present invention, the shaft portion is formed on the first base portion in which shaft portions that can be inserted into a plurality of flaw detection coils each formed by winding a conducting wire are provided. A second base portion having a through-hole through which the through-hole can be inserted is connected to the through-hole while the shaft portion is inserted, and a holder substrate having a receiving hole for supporting the flaw detection coil is placed on the second base. A step of inserting the plurality of flaw detection coils into the shaft portion, a step of fixing the flaw detection coils to the coil substrate, and forming a recess filled with a coating layer in contact with the surface to be inspected. Fixing the coil substrate to a coil holder having substantially the same thermal expansion coefficient as the coil substrate, removing the coil holder from the second base portion, and filling the recess with the coating layer; Characterized in that it comprises the step of attaching the coil holder to a housing portion having a serial coil holder substantially the same thermal expansion coefficient.

The method of manufacturing the eddy current flaw detection multi-coil probe further includes mounting a flaw detection coil on a coil substrate having substantially the same thermal expansion coefficient as the coil holder, and further providing a housing having substantially the same thermal expansion coefficient as the coil holder and the coil substrate. Since it is mounted, even if the ambient temperature rises or the probe temperature rises due to the heat generated by the probe itself, it is possible to cause substantially the same length change between the coil holder and the housing, and the coil holder is bent. Can be suppressed.
In addition, the flaw detection coil can be mounted without a coil holder, and a wide working pace can be secured to improve workability.

  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 and 3, the eddy current flaw detection multi-coil probe 1 has a plurality of flaw detection coils 8 formed by winding a conducting wire and a facing surface 10a facing the inspection target surface T1. A holding part 12 having a coil holder 10 for supporting the flaw detection coil 8 in a state where the end face 8a of the flaw detection coil 8 is directed, a coating layer 11 in contact with the inspection target surface T1, a housing 13 for supporting the holding part 12, and a flaw detection And a multiplexer substrate 15 for switching the channel of the coil 8.

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 a thermoplastic resin, for example, a base resin made of polycarbonate, filled with 20% of an inorganic filler (glass-like member) such as glass fiber. The thermal expansion coefficient of polycarbonate filled with 20% glass fiber is set to be approximately the same as the thermal expansion coefficient of aluminum, which is the material of the housing 13. Here, the shape of the coil holder 10 may be formed by processing a resin, or may be formed by injection molding or the like.

  The coil holder 10 is formed with a plurality of substantially cylindrical accommodation holes 17 penetrating in the thickness direction (Z direction), and the flaw detection coils 8 are accommodated in the accommodation holes 17 respectively. These accommodation holes 17 are arranged along the longitudinal direction (X direction) of the coil holder 10, for example, in two rows, with the accommodation holes 17 in each row being 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.

The coil holder 10 is formed so that the dimension in the width direction (Y direction) gradually increases from the facing surface 10a side upward in the Z direction. 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 linear shape, but may be formed in, for example, a substantially convex curved surface shape that smoothly connects the side surface 10b of the coil holder 10 and the facing surface 10a.
The coil holder 10 includes a positioning hole 10c and a long hole 10d (shown in FIG. 4A) that can penetrate a positioning pin 32 disposed in a first base portion 28, which will be described later. A concave portion 10e having a substantially rectangular shape in a sectional view is formed on the facing surface 10a side.

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 e 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 coating layer 11 may be mixed with an inorganic filler so as to have the same thermal expansion coefficient.
On both side surfaces of the coil holder 10, markings (index portions) 20 by groove-shaped smearing or the like are disposed at locations where the X direction center portions and the outermost portions of the plurality of flaw detection coils 8 are located.

  The housing 13 includes a first housing 21, a second housing 22, and a housing lid 23 made of, for example, aluminum. The first housing 21 is formed in an 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 an L shape that is substantially symmetrical to the first housing 21.
That is, the housing 13 is formed in a 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 with reference to FIGS.
This manufacturing method includes a positioning pin (S01) on the first base portion 28 on which a plurality of positioning pins (shaft portions) 27 that can be inserted into the plurality of flaw detection coils 8 are erected. A step (S02) of connecting the second base portion 30 while engaging the through hole 30a through which the pin 27 can penetrate and the positioning pin 27 to place the coil holder 10 on the second base portion 30; A step (S03) for inserting a plurality of flaw detection coils 8 into a step, a step (S04) for fixing the flaw detection coils 8 to the coil holder 10, and removing the coil holder 10 from the second base portion 30 to apply the coating layer 11 to the recess 10e. A filling step (S05) and a step (S06) of attaching the coil holder 10 to the housing 13 are provided.

  First, a coil holder is prepared by adding 20% glass fiber to the total weight of polycarbonate. At this time, it is performed by resin machining or injection molding.

Next, the process proceeds to the step of mounting the flaw detection coil 8 (S02).
Here, the 1st base part 28 and the 2nd base part 30 shall be used as a jig | tool for an assembly. The first base portion 28 further includes a first flat surface 28 a for placing the second base portion 30, a pin 31 for positioning the second base portion 30, and the coil holder 10 for fixing the first holder 28 on the first base portion 28. The positioning pin 32 of the coil holder 10 is provided.

The positioning pin 27 protrudes from the first flat surface 28a so as to be higher than the plate thickness of the second base portion 30 and lower than the height when the flaw detection coil 8 is placed on the second flat surface 30b described later. Are arranged in two rows in the X direction in the figure. The outer diameter of the positioning pin 27 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 27 is 1.06 mm.
In addition, the positioning pins 27 are arranged in two rows along the longitudinal direction (X direction), and at positions where the positioning pins 27 in each row are offset, in the same manner as the housing hole 17 of the coil holder 10 described above. Yes.

The second base portion 30 includes a second flat surface 30b on which the coil holder 10 is placed, and an opening 33a through which the through hole 30a and the positioning pin 32 can be inserted, and protrudes from the second flat surface 30b. A portion 33 and a grip portion 35 protruding in the Y direction from the first base portion 28 are provided.
The through holes 30a have a width wider than the straight diameter of the positioning pins 27, and are formed in two rows extending longer than the length of each row of the positioning pins 27 in the X direction.
The opening 33 a is arranged with a diameter wider than the diameter of the positioning pin 32. A mounting surface 33 b for mounting the flaw detection coil 8 is disposed on the stepped portion 33.

  On the first base portion 28 as described above, the second base portion 30 is placed between the pins 31 while the positioning pin 27 is inserted through the through hole 30a and the positioning pin 32 is inserted through the opening portion 33a. The bonding jig 36 is set.

  In this step, the coil holder 10 is placed on the bonding jig 36 so that the facing surface 10a of the coil holder 10 is in contact with the second flat surface 30b of the second base portion 30 in this step. To do. At this time, by positioning the positioning hole 10c and the long hole 10d of the coil holder 10 into the two positioning pins 32 of the bonding jig 36, the coil holder 10 is positioned in the X and Y directions, and the recess 10e. And the stepped portion 33 are fitted.

Next, the process proceeds to the step of inserting the flaw detection coil 8 (S03).
First, the flaw detection coils 8 are attached to the plurality of positioning pins 27, respectively. At this time, since the positioning pins 27 are arranged to be offset from each other, the flaw detection coils 8 are attached to the respective positioning pins 27 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 be in contact with the mounting surface 33 b of the step portion 33. As a result, the positions of the flaw detection coils 8 in the Z direction are aligned. At this time, since the height of the stepped portion 33 is smaller than the depth of the concave portion 10e, the end surface 8a of the flaw detection coil 8 is disposed at a position protruding into the concave portion 10e.
In this state, since the flaw detection coil 8 and the coil holder 10 are both fixed to the bonding jig 36, the relative positions of the flaw detection coil 8 and the coil holder 10 are determined.

And it transfers to the process (S04) which fixes the flaw detection coil 8 to the coil holder 10. FIG.
Here, it is fixed by an adhesive G.
Examples of the adhesive G used here include UV adhesives (World Lock 8463 (Kyoritsu), World Rock 8403 (Kyoritsu), World Rock 8130 (Kyoto), World Rock 8840 (Kyoto), 836TNS (Kyoto). Vertical), 326UVBLUE (Loctite)), instantaneous adhesive (Aron α (cemedine)) epoxy adhesive, urethane adhesive, silicon adhesive and the like.

In bonding, it is preferable that each flaw detection coil 8 is pressed against the mounting surface 33b and the coil holder 10 is pressed against the second flat surface 30b. Thereby, the position of the end surface 8a of the plurality of flaw detection coils 8 in the Z direction can be reliably aligned.
In this case, the coil holder 10 may be placed on the bonding jig 36 after the flaw detection coil 8 is attached to the positioning pin 27.

Next, the process proceeds to the step of filling the coating layer 11 (S05).
Here, first, with the second base portion 30 and the coil holder 10 attached, the grip portion 35 of the second base portion 30 is gripped, and the second base portion 30 is moved upward along the pin 31 (Z Direction). At this time, the second base portion 30 is not tilted and pulled out with respect to the first base portion 28, so that the load from the positioning pin 27 is not applied to the flaw detection coil 8 and the flaw detection coil 8 is not damaged. In addition, the flaw detection coil 8 can be pulled out smoothly while suppressing the drop off.
Thereafter, the coil holder 10 is removed from the second base portion 30 to complete the coil bonding.

Then, as shown in FIGS. 5A and 5B, the coil holder 10 is mounted so that the facing surface 10a of the coil holder 10 to which the flaw detection coil 8 is fixed comes into contact with the surface 37a of the coating layer jig 37. Put. Then, an epoxy resin as a material of the coating layer 11 is applied from each of the positioning hole 10c, the long hole 10d, the accommodation hole 17, and the flaw detection coil 8 of the coil holder 10 so as to fill the recess 10e.
Here, the positioning hole 10c and the long hole 10d are diverted to those used for positioning the coil holder 10 when the flaw detection coil 8 is bonded.
As a result, the flaw detection coil 8 and the coil holder 10 are fixed to each other via the coating layer 11, so that both can be reliably fixed.
Thus, the coating layer 11 is cured to complete the creation of the coating layer 11, and the holding unit 12 is completed.

In addition, you may fill the accommodation hole 17 with an epoxy resin. In this case, the flaw detection coil 8 can be more firmly fixed.
As a material of the coating layer, a material having rigidity lower than that of the coil holder 10 and elastic such as silicon resin, urethane resin, and Teflon (registered trademark) resin may be used. By making 11 follow, the bending of the coil holder 10 due to a temperature change can be eliminated.

Here, the coating layer 11 is more preferably formed from a material having excellent wear resistance because it directly rubs against the surface T1 to be inspected when detecting scratches.
In addition, it is preferable that the coil holder 10 is pressed against the surface 37a of the coating layer jig 37 when bonding and curing. Thereby, the surface 11a of the coating layer 11 can be created as a smooth surface in accordance with the same height as the facing surface 10a of the coil holder 10 in the Z direction.
At this time, by applying a release agent to the surface 37a of the coating layer jig 37, the coating layer jig 37 and the holding portion 12 on which the coating layer 11 is disposed can be easily peeled off. The surface of the layer 11 can be smoothed.
Furthermore, by performing defoaming (vacuum defoaming) when the coating layer 11 is cured, the coating layer 11 without bubbles can be obtained.

And the process (S06) of attaching the coil holder 10 to the housing 13 is performed.
Here, after removing the holding part 12 from the coating layer jig 37, the flexible cable 16 and a coil terminal (not shown) 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 adhesion or the like.
Next, the cable 3 is attached to the multiplexer substrate 15, and the end of the flexible cable 16 is attached to the connector 15 a of the multiplexer substrate 15.

  Thus, the multiplexer substrate 15 is attached to the first housing 21, the second housing 22 is attached to the first housing 21, and the holding portion 12 is assembled to the bottoms of the first housing 21 and the second housing 22 and fixed by screwing or the like. Finally, the cable gland cover 25 and the housing lid 23 are attached to complete the assembly.

When the eddy current flaw detection multi-coil probe 1 performs flaw detection on the inspection target surface T1, as shown in FIG. 3B, the inspection target surface T1 is in contact with the opposing surface 10a of the coil holder 10. The eddy current flaw detection multi-coil probe 1 is moved in the width direction (Y direction) of the coil holder 10.
At this time, the area within the marking 20 indicating the coil mounting position moves as a flaw-detectable area.

Table 5 shows the relationship between the difference in lift-off due to the deflection of the coil holder 10 generated with respect to the ambient temperature and the sensitivity difference between the central portion and both end portions of the coil holder 10 at that time. The specifications of the coil holder 10 at this time are also shown in Table 4. Here, the length in the table indicates the length of the coil holder 10 in the X direction, the width indicates the length in the Y direction, and the height indicates the length in the Z direction.
It can be seen that even when the environmental temperature changes, the changes in the lift-off amount and the sensitivity difference are remarkably smaller than the temperature change amount.

According to this eddy current flaw detection multi-coil probe 1, the coil holder 10 and the housing 13 change in substantially the same temperature even when the environmental temperature rises or the probe temperature rises due to heat generation of the probe itself. The bending of the coil holder 10 can be suppressed.
Accordingly, it is possible to reduce the lift-off variation of the flaw detection coil 8 to suppress an increase in sensitivity variation and improve the inspection accuracy.

In particular, since the coil holder 10 is made of polycarbonate having an inorganic filler made of glass fiber, the coefficient of thermal expansion of the coil holder 10 can be made closer to the same thermal expansion coefficient as that of the housing.
Further, since the taper portion 18 is arranged, even when an obstacle such as a protrusion protruding from the inspection target surface T1 exists in front of the moving direction of the eddy current flaw detection multi-coil probe 1 during movement, the taper portion 18 is smoothly guided to the opposing surface 10a of the coil holder 10, and the holding portion 12 can be smoothly moved with respect to the inspection target surface T1 regardless of the presence or absence of an obstacle.

  Further, since the holding portion 12 is moved in a state where the coating layer 11 is in contact with the inspection target surface T1, the end surface 8a of the flaw detection coil 8 does not directly contact the inspection target surface T1 when detecting a flaw. Can be protected. Further, by using a material having elasticity such as silicon resin, urethane resin, Teflon (registered trademark) resin as the material of the coating layer 11, the terminal portion of the flaw detection coil 8 (not shown) is filled with the coating layer 11. Even if some impact force is applied to the eddy current flaw detection multi-coil probe 1 during work or flaw detection, the load on the flaw detection coil terminal (not shown) can be reduced and the occurrence of disconnection can be suppressed.

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.
In addition, since the marking 20 is provided, the inspection target surface T1 can be accurately arranged within the possible flaw detection range by the flaw detection coil in a state where the lift-off is small, and the flaw detection accuracy can be further improved.

Next, a second embodiment will be described with reference to FIGS.
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 holding portion 41 of the eddy current flaw detection multi-coil probe 40 according to this embodiment is electrically connected to each flaw detection coil 8 as shown in FIG. The flaw detection coil 8 is supported by the coil holder 43 via the coil substrate 42.

The coil substrate 42 is made of a material such as glass epoxy, and the thermal expansion coefficient of the coil substrate 42 and the thermal expansion coefficient of the coil holder 43 are substantially the same.
As shown in FIG. 7 and FIG. 8, a plurality of substantially cylindrical accommodation holes 17 penetrating in the thickness direction (Z direction) are formed in the coil substrate 42, and the flaw detection coils 8 are respectively provided in these accommodation holes 17. Contained. The inner diameters of the receiving holes 17 are formed larger than the outer diameter of the flaw detection coil 8. The accommodation holes 17 are arranged in two rows in the longitudinal direction of the coil substrate 42, for example, along the X direction, and the accommodation holes 17 in each row are offset. Each flaw detection coil 8 is fixed to the coil substrate 42 by fixing its peripheral edge to the inner peripheral side of the accommodation hole 17 with an adhesive G.

The coil substrate 42 includes a connector 46 to which one end of the flexible cable 45 is connected, a pattern 47 for connecting a coil terminal (not shown) of the flaw detection coil 8 with solder, a positioning hole 42a, and a long hole 42b. Has been.
Note that the other end of the flexible cable 45 is connected to the connector 15a of the multiplexer substrate 15, whereby the multiplexer substrate 15 and the flaw detection coil 8 are electrically connected.

The outer shape of the coil holder 43 is the same as that of the coil holder 43 according to the first embodiment, but when the coil substrate 42 is inserted into the inner surface from below in the Z direction, the coil substrate 43 A flange portion 48 that protrudes inward at a height at which the surface 42A of 42 is locked is disposed.
In the holding portion 41, a recess 42e is formed by the coil holder 43 and the back surface 42B of the coil substrate 42, and the coating layer 11 is disposed in the recess 42e.

Next, a method for manufacturing the eddy current flaw detection multi-coil probe 40 according to the present invention will be described.
This manufacturing method includes a step of placing a holder substrate on the second base portion 30 connected on the first base portion 28 (S11), and a step of inserting a plurality of flaw detection coils 8 through the positioning pins 27 (S12). The step of fixing the flaw detection coil 8 to the coil substrate 42 (S13) and the step of fixing the coil substrate 42 to the coil holder 43 by forming the recess 42e filled with the coating layer 11 in contact with the surface to be inspected (S14). And the step (S15) of removing the coil holder 43 from the second base portion 30 and filling the coating layer with the coating layer 42e, and the step of attaching the coil holder 43 to the housing 13 (S16).

  In the step (S11) of placing the holder substrate 42, as shown in FIG. 8, the positioning pins 32 of the bonding jig 36 are inserted into the positioning holes 42a and the long holes 42b of the coil substrate 42 so as to be aligned. Then, the coil substrate 42 is positioned in the X and Y directions. Further, by positioning the back surface 42B of the coil substrate 42 on the mounting surface 33b of the stepped portion 33, the positioning in the Z direction is performed.

In the step of inserting the flaw detection coil 8 (S12), the same operation as the step of inserting the flaw detection coil 8 in the first embodiment (S03) is performed.
Here, by aligning the end surface 8a of the flaw detection coil 8 with the mounting surface 33b of the stepped portion 33, the end surface 8a of the flaw detection coil 8 and the back surface 42B of the coil substrate 42 coincide with each other, and positioning relative to the coil substrate 42 is performed. .

  In the step (S13) of fixing the flaw detection coil 8 to the coil substrate 42, the same operation as the step (S04) of fixing the flaw detection coil 8 according to the first embodiment to the coil holder 43 is performed instead of the coil holder 43. This is performed on the coil substrate 42 to obtain the state shown in FIG.

In the step (S14) of fixing the coil substrate 42 to the coil holder 43, as shown in FIG. 10, the facing surface 43a of the coil holder 43 is in contact with the second flat surface 30b of the second base portion 30, and The coil holder 43 is placed on the bonding jig 36 so that the bottom surface 48a of the flange portion 48 of the coil holder 43 and the surface 42A of the coil substrate 42 placed on the mounting surface 33b of the second base portion 30 are in contact with each other. .
That is, the distance from the facing surface 43a of the coil holder 43 to the bottom surface 48a of the flange portion 48 of the coil holder 43 is substantially the same as the combined distance of the step portion 33 of the second base portion 30 and the thickness of the coil substrate 42. Has been.

At this time, the coil holder 43 is positioned in the X and Y directions by inserting the two positioning pins 32 of the bonding jig 36 in accordance with the positioning holes 43 c and the long holes 43 d of the coil holder 43.
In this state, the coil substrate 42 and the coil holder 43 are fixed with an adhesive (not shown).
It is preferable to perform the bonding while pressing the flaw detection coil 8 against the mounting surface 33b and pressing the coil holder 43 against the second flat surface 30b. As a result, the positions of the end faces 8a of the plurality of flaw detection coils 8 in the Z direction can be aligned in an autistic manner.

After the end of the flaw detection coil 8 is electrically connected to the pattern 47 of the coil substrate 42 with solder or the like, the coil holder 43 is detached from the second base portion 30 and the coating layer is recessed as in the first embodiment. The assembly process is completed by performing the step (S15) of filling 42e and the step (S16) of attaching the coil holder 43 to the housing 13.
The terminal of the flaw detection coil 8 may be electrically connected to each of the patterns 47 of the coil substrate 42 before the step of fixing the flaw detection coil 8 to the coil substrate 42 (S14).

According to this eddy current flaw detection multi-coil probe 40, the same operation and effect as the first embodiment can be obtained.
In particular, the flaw detection coil 8 can be attached to the coil substrate 42 without the coil holder 43, and a wide working pace can be secured to improve workability.

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 first embodiment is that the holding portion 51 of the eddy current flaw detection multi-coil probe 50 according to this embodiment has a substantially square frame shape that can be fitted to the housing 13. When the formed coil holder 52, the coating layer 11 disposed at the bottom of the coil holder 52, and a filler 55 made of foaming resin filled on the coating layer 53 in the coil holder 52 are provided. This is the point.
By using the foamed resin, the rigidity becomes lower than that of the coil holder 52, and the filler 55 can follow the deformation accompanying the temperature change of the coil holder 52.

  The material of the coating layer 53 may be a resin sheet having a thermal expansion coefficient substantially the same as the thermal expansion coefficient of the coil holder 52 or a mixture of an inorganic filler. In this case, the thermal expansion coefficient becomes the same as the thermal expansion coefficient of the coil holder 52, and the thermal expansion coefficient of the holding part 51 including the coil holder 52 and the coating layer 53 can be made uniform.

The coating layer 53 may be made of a material having rigidity lower than that of the coil holder 52, such as silicon resin, urethane resin, or Teflon (registered trademark) resin. By causing the layer 53 to follow, the bending of the coil holder 52 due to a temperature change may be further suppressed.
However, the coating layer 53 is preferably formed of a material having excellent wear resistance because the coating layer 53 is directly contacted and rubbed against the inspection target surface T1 when the scratch is detected.
The filler 55 is not limited to the foamed resin, but may be any material that has elasticity with low rigidity such as rubber and can be filled into the frame of the coil holder 52 to fix the flaw detection coil 8.

A method for manufacturing the holding portion 51 of the eddy current flaw detection multi-coil probe 50 will be described.
First, the end surface 8a of the flaw detection coil 8 is placed on the coating layer 53 that is previously formed in a sheet shape and has a uniform thickness so as to be in contact with the upper surface 53a of the coating layer 53, and is fixed with an adhesive or the like. At this time, the position of the flaw detection coil 8 in the X and Y directions is determined using a jig (not shown).
Next, the filler 55 is filled into the frame of the coil holder 52 in a state where the coating layer 53 to which the flaw detection coil 8 is fixed is inserted into the frame of the coil holder 52.
In this way, the holding part 51 is formed.

  As in the second embodiment, the flaw detection coil 8 is fixed to a coil substrate (not shown), placed in the coil holder 52, filled with a filler 55, and a sheet-like coating layer 53 prepared in advance. Alternatively, the coating layer 53 may be formed using the bonding jig 36 described in the first embodiment.

According to the eddy current flaw detection multi-coil probe 50, the thermal expansion coefficients of the housing 13 and the coil holder 52 are substantially the same even when the probe temperature is changed. Can be suppressed.
Since the rigidity of the filler 55 is low, it can be deformed by following the temperature change of the coil holder 52, and the relative distance between the flaw detection coil 8 fixed to the filler 55 and the inspection target surface T1 is not changed. In addition, the occurrence of lift-off can be suppressed.

Further, the coil holder 52 can be made of a metal such as aluminum, which is the same material as the housing 13, and the rigidity of the probe itself can be increased.
Further, since the coil holder 52 is formed in a frame shape, parts can be diverted when manufacturing another type of eddy current flaw detection multi-coil type probe having a different arrangement and shape of the flaw detection coil 8, and the manufacturing cost can be reduced. .
That is, in eddy current flaw detection, it is necessary to make the shape of the eddy current flaw detection multi-coil probe in accordance with the object to be measured (flaw detection coils (shape and characteristics), number of flaw detection coils, and flaw detection coil intervals vary). Therefore, it can be said that reducing the manufacturing cost has a great meaning that the parts can be shared.

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-described embodiment, the marking 20 has a groove shape by smearing or the like. However, the marking 20 is not limited to this, and as shown in FIG. 12, the marking filled in the concave portion 61 provided on the side surface 60b of the coil holder 60. As shown in FIG. 13, as shown in FIG. 13, it may be a marking 65 with a rounded smear on the side surface 63 b of the coil holder 63, or may be printed (silk screen, tampo printing, hot stamp), etc. It is only necessary to mark the sensor so that the position of the sensor (coil position) can be understood.

In the first embodiment, the cable 3 is fixed to the eddy current flaw detection multi-coil probe 1. However, as shown in FIG. 14, the connector 67 a is attached to the first housing 67 of the housing 66 and the cable 68 is connected. The connector 68a may be attached to the eddy current flaw detection multi-coil probe 70 and the cable 68 so as to be detachable. In this case, the cable can be replaced with a cable having a length or hardness according to the application, and the operability can be improved.
In eddy current flaw detection, it is necessary to prepare eddy current flaw detection multi-coil probes each having characteristics according to the object to be measured. However, since there is no need to prepare a cable for each probe, the cost of the probe can be reduced. .

Furthermore, in the said 1st Embodiment, although the base resin of the material of the coil holder 10 is made of polycarbonate, it may be a thermoplastic resin other than this, or a thermosetting resin.
Other thermoplastic resins include, for example, PA (nylon), PBT (polybutylene terephthalate), PES (polyethersulfone), PPS (polyphenylene sulfide), and polymer alloys combining a plurality of base resins. Good. Moreover, as a thermosetting resin, an epoxy resin, unsaturated polyester, etc. may be sufficient, for example.

Moreover, although the inorganic filler is made of glass fiber, it may be spherical or tetrapotted. The inorganic filler may be carbon, potassium titanate, graphite, molybdenum disulfide, silica, glass, alumina, talc (registered trademark), clay, mica, iron powder, aluminum hydroxide, and the like.
That is, it is only necessary that the thermal expansion coefficient can be made substantially the same as the thermal expansion coefficient of the housing by the combination of the base resin and the inorganic filler. Examples include resins as shown in Table 6. Table 3 shows the base resin / filler filling amount (GF is an abbreviation for glass fiber) and the thermal expansion coefficient.

The resin constituting the coil holder may be an epoxy resin whose thermal expansion coefficient can be changed depending on the filling amount of the inorganic filler.
For example, Table 7 shows the relationship between the filler filling amount and the thermal expansion coefficient of a resin material filled with silica (SiO ₂ ) as an inorganic filler with respect to the base resin.

Table 9 shows the relationship between the coefficient of thermal expansion and the sensitivity variation with respect to the specifications of the coil holder shown in Table 8.
It can be seen that the coefficient of thermal expansion can be adjusted by adjusting the filling amount of the inorganic filler, and the sensitivity variation at high temperatures can be changed. In other words, it is possible to create an eddy current flaw detection multi-coil probe in accordance with sensitivity variations at high temperatures determined by product specifications.

The housing 13 is made of aluminum, but may be any material that can support the coil holder as the housing. From the viewpoint of EMC and EMI, metal, metal foil or conductive coating on the surface, or conductive filler It is desirable to be a resin mold that can shield electromagnetic waves using a resin material mixed with.
For example, when using a titanium housing, the constituent material of the coil holder is selected from materials filled with an inorganic filler and having a coefficient of thermal expansion that is substantially the same as the coefficient of thermal expansion of the housing. An increase can be prevented.

In the first embodiment, the multiplexer substrate 15 and the flexible cable 16 are separated from each other and connected to each other via the connector 15a of the multiplexer substrate 15. However, a connector (not shown) is provided on the flexible cable side. The connection pins (not shown) may be arranged on the multiplexer substrate side.
Moreover, it is good also as a rigid flexible (not shown) structure which integrated the multiplexer substrate and the flexible cable. By doing so, it is possible to reduce the number of parts such as a connector rest.
Furthermore, it is good also as a structure (not shown) which mounts a multiplexer board | substrate in a flexible cable. By doing so, the eddy current flaw detection multi-coil probe can be miniaturized.

Moreover, in the said 2nd Embodiment, although the back surface 42B of the coil board | substrate 42 and the end surface 8a of the flaw detection coil 8 are made the same height, as shown to Fig.15 (a), it is rather than the back surface 42B of the coil board | substrate 42. It is good also as the holding part 70 which made the end surface 8a of the flaw detection coil 8 protrude.
In this case, in assembling the coil holder 72 and the coil substrate 42 to which the flaw detection coil 8 is attached, as shown in FIG. 15 (b), from the facing surface 72a of the coil holder 72 to the bottom surface 48a of the flange portion 48. A spacer 73 is used in which the distance is substantially the same as the distance obtained by combining the thickness of the stepped portion 33 of the second base portion 30 and the spacer 73 and the thickness of the coil substrate 42.

That is, the coil substrate 42 is placed with the spacer 73 inserted between the back surface 42 </ b> B of the coil substrate 42 and the mounting surface 33 b of the stepped portion 33 of the second base portion 30.
Then, the end surface 8 a of the flaw detection coil 8 contacts the mounting surface 33 b of the step portion 33 of the second base portion 30 so that the facing surface 72 a of the coil holder 72 contacts the second flat surface 30 b of the second base portion 30. The coil holder 72 is placed on the bonding jig 36 so that the bottom surface 48a of the flange portion 48 of the coil holder 72 is in contact with the surface 42A of the coil substrate 42.
At this time, the end surface 8a of the flaw detection coil 8 and the mounting surface 33b of the stepped portion 33 coincide with each other, and a gap is generated between the back surface 42B of the coil substrate 42 and the end surface 8a of the flaw detection coil 8.
Fix in this state. At this time, it is preferable to perform this while pressing the flaw detection coil 8 against the mounting surface 33b and pressing the coil holder 72 against the second flat surface 30b.

  In this case, since the Z direction between the flaw detection coil 8 and the coil holder 72 is positioned by the bonding jig 36, the end surface 8 a of the flaw detection coil 8 may protrude from the back surface 42 </ b> B of the coil substrate 42. Therefore, the accuracy of the flatness of the coil substrate 42 can be relaxed.

Further, as shown in FIG. 16, the end surface 8a of the flaw detection coil 8 protrudes from the back surface 42B of the coil substrate 42, and there is a gap between the bottom surface 76a of the flange portion 76 of the coil holder 75 and the surface 42A of the coil substrate 42. The holding portion 77 provided may be used.
In this case, in the assembly of the coil holder 75 and the coil substrate 42 to which the flaw detection coil 8 is attached, the distance from the facing surface 75 a of the coil holder 75 to the bottom surface 76 a of the flange portion 76 is the step of the second base portion 30. The spacer which becomes substantially the same as the distance which combined the thickness of the part 33 and the spacer which is not illustrated, and the thickness of the coil board | substrate 42 is used.

That is, when the coil holder 75 and the coil substrate 42 are fixed, the coil substrate is inserted with a spacer between the back surface 42B of the coil substrate 42 and the mounting surface 33b of the stepped portion 33 of the second base portion 30. 42 is placed so that the end surface 8a of the flaw detection coil 8 is in contact with the mounting surface 33b. Then, the coil holder 75 is placed on the bonding jig 36 so that the facing surface 75 a of the coil holder 75 is in contact with the second flat surface 30 b of the second base portion 30.
At this time, there is a gap between the bottom surface 76a of the flange portion 76 of the coil holder 75 and the surface 42A of the coil substrate 42, but an adhesive is wound around this portion or between the flange portion 76 and the coil substrate 42. Adhere and fix so as to bridge with. At this time, it is preferable to perform this while pressing the flaw detection coil 8 against the mounting surface 33b and pressing the coil holder 75 against the second flat surface 30b.

In this case, the facing surface 75 a of the coil holder 75 matches the second flat surface 30 b of the second base portion 30, and the end surface 8 a of the flaw detection coil 8 matches the mounting surface 33 b of the stepped portion 33.
Thus, since the Z direction between the flaw detection coil 8 and the coil holder 75 is positioned by the bonding jig 36, the end surface 8a of the flaw detection coil 8 protrudes from the back surface 42B of the coil substrate 42, and the surface of the coil substrate 42 A gap may be provided between 42A and the bottom surface 76a of the flange portion 76 of the coil holder 75, and the flatness and tolerance of the bottom surface 76a of the flange portion 76 of the coil holder 75 and the thickness tolerance of the coil substrate 42 are loosened. be able to.

  Moreover, as shown in FIG. 17, the connector 46 mounted on the coil substrate 42 may be arranged at the end in the longitudinal direction (X direction). Depending on the position of the coil substrate 42 with respect to the flexible cable 45, connection to the connector 46 can be easily performed.

Further, as shown in FIG. 18, the coil substrate 42 may be inserted into the coil holder 78 from above the flange portion 80.
In this case, the positioning of the facing surface 78a of the coil holder 78 and the end surface 8a of the flaw detection coil 8 is performed by adjusting the thickness of the spacer 73 used during assembly.
Further, the fixing of the coil substrate 42 and the flaw detection coil 8 and the connection of the terminals may be performed in a separate process in advance. In this case, the coil substrate 42 in which the positioning of the flaw detection coil 8 and the connection of the coil terminals has been completed in advance is inserted from above the coil holder 78 and placed and fixed on the flange portion 80.

Further, as shown in FIG. 19, a rigid flexible coil substrate 83 in which a coil substrate 81 and a flexible cable 82 are integrated may be used.
In this case, by connecting the flexible cable 82 and the connector 15a of the multiplexer substrate 15, it is possible to achieve the same operations and effects as in the second embodiment, and it is possible to reduce the number of components.
The cable arranged on the coil substrate 81 may be a lead wire or a coaxial cable instead of a flexible cable.

Conversely, a rigid flexible multiplexer substrate (not shown) in which the multiplexer substrate and the flexible cable are integrated may be used. Also in this case, a lead wire or a coaxial cable may be projected from the multiplexer substrate.
In this case, the same effect as described above can be obtained.

  Furthermore, it is good also as what integrated the multiplexer board | substrate, the coil board | substrate, and the flexible cable, and connected the multiplexer board | substrate and the coil board | substrate directly with the lead wire or the coaxial cable.

Further, the multiplexer substrate may be mounted on the flexible substrate.
In this case, in addition to the same effects as described above, the eddy current flaw detection multi-coil probe can be downsized.

1 is a perspective view showing an eddy current flaw detection apparatus including an eddy current flaw detection multi-coil probe according to a first embodiment of the present 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. It is a disassembled perspective view which shows the (a) structure of the eddy current test multicoil type probe which concerns on the 1st Embodiment of this invention, (b) It is sectional drawing of a holding 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 (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 a disassembled perspective view which shows the structure of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention. It is the (a) perspective view and (b) sectional view showing the holding part of the eddy current flaw detection multi-coil type probe concerning a 2nd embodiment of the present invention. It is explanatory drawing which shows the manufacturing method of the eddy current test multi coil type probe which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the assembly process of the holding | maintenance part of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention, (b) It is a perspective view which shows the coil board | substrate with which the test coil was mounted | worn. (A) Sectional drawing which shows the assembly process of the holding | maintenance part of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention, (b) A perspective view which shows a holding part, (c) It is sectional drawing which shows a holding part. is there. It is explanatory drawing which shows the (a) manufacturing method of the eddy current test multicoil type probe which concerns on the 3rd Embodiment of this invention, (b) It is sectional drawing which shows a holding part. It is a principal part perspective view which shows the modification of the eddy current test multi-coil type probe which concerns on the 1st Embodiment of this invention. It is a principal part perspective view which shows the modification of the eddy current test multi-coil type probe which concerns on the 1st 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 1st Embodiment of this invention. It is sectional drawing which shows the (a) holding | maintenance part as a modification of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention, (b) It is sectional drawing which shows the middle of assembly of a holding | maintenance part. It is sectional drawing which shows the holding | maintenance part as a 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 coil board | substrate as a modification of the eddy current test multi-coil type probe which concerns on the 2nd Embodiment of this invention. It is a disassembled block diagram which shows the holding | maintenance part as a 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 coil board | substrate as a modification of the eddy current test multi-coil type probe which concerns on the 2nd 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.

Explanation of symbols

1, 40, 50 Eddy current flaw detection multi-coil probe 8 Flaw detection coil 8a End face 10, 43, 52, 60, 63, 72, 75, 78 Coil holder 10a, 72a Opposing face 11, 53 Coating layer 12, 41, 51, 70 , 77 Holding part 13, 66 Housing 20, 62, 65 Marking (indicator part)
21, 67 First housing 22 Second housing 42, 81 Coil substrate 55 Filler

Claims (13)

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 housing for supporting the holding portion,
The eddy current flaw detection multi-coil probe characterized in that the coefficient of thermal expansion of the coil holder and the coefficient of thermal expansion of the housing are substantially the same.   The eddy current flaw detection multi-coil probe according to claim 1, wherein the coil holder is made of a resin having an inorganic filler.   The eddy current flaw detection multi-coil probe according to claim 2, wherein the resin is a thermoplastic resin, and the inorganic filler is a glass-like member.   The eddy current flaw detection multi-coil probe according to claim 2, wherein the resin is an epoxy resin whose thermal expansion coefficient can be changed according to a filling amount of the inorganic filler. The holding portion includes a coil substrate electrically connected to each of the flaw detection coils,
The plurality of flaw detection coils are supported by the coil holder via the coil substrate,
2. The eddy current flaw detection multi-coil probe according to claim 1, wherein a thermal expansion coefficient of the coil substrate and a thermal expansion coefficient of the coil holder are substantially the same. The coil holder is formed in a frame shape and at least partially filled with an elastic filler,
The eddy current flaw detection multi-coil probe according to claim 1, wherein the plurality of flaw detection coils are supported by the coil holder via the filler.   The eddy current flaw detection multi-coil probe according to claim 6, wherein the filler is a foamed resin. The holding part includes a coating layer in contact with the surface to be inspected,
8. The eddy current flaw detection multi-coil probe according to claim 1, wherein a thermal expansion coefficient of the coating layer and a thermal expansion coefficient of the coil holder are substantially the same.   The eddy current flaw detection multi-coil probe according to any one of claims 1 to 7, wherein the coating layer has elasticity.   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 claim 1.   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 coil holder forming step including a housing hole for supporting a plurality of flaw detection coils formed by winding a conducting wire, and a recess filled with a coating layer that comes into contact with the surface to be inspected;
A second base part in which a through-hole through which the shaft part can pass is arranged on the first base part provided with a shaft part that can be inserted into each of the plurality of flaw detection coils. Inserting the coil holder and placing the coil holder on the second base part; and
Inserting the plurality of flaw detection coils into the shaft portion;
Fixing the flaw detection coil to the coil holder;
Removing the coil holder from the second base portion and filling the recess with the coating layer;
And a step of attaching the coil holder to a housing part having substantially the same thermal expansion coefficient as that of the coil holder. A method for manufacturing an eddy current flaw detection multi-coil probe. On the first base portion where shaft portions that can be inserted into a plurality of flaw detection coils each formed by winding a conducting wire are erected, a second base portion in which a through hole through which the shaft portion can be penetrated is disposed through the second base portion. Placing the holder substrate provided with an accommodation hole for supporting the flaw detection coil on the second base, while connecting the shaft portion through the hole; and
Inserting the plurality of flaw detection coils into the shaft portion;
Fixing the flaw detection coil to the coil substrate;
Forming a recess filled with a coating layer in contact with the surface to be inspected, and fixing the coil substrate to a coil holder having substantially the same thermal expansion coefficient as the coil substrate;
Removing the coil holder from the second base portion and filling the recess with the coating layer;
And a step of attaching the coil holder to a housing part having substantially the same thermal expansion coefficient as that of the coil holder. A method for manufacturing an eddy current flaw detection multi-coil probe.

Images