JPH11183441A - Rotary eddy current flaw detector - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a flaw detection device that can reliably and accurately detect a flaw in accordance with the shape of a flaw-detected body. SOLUTION: An eddy current flaw detection coil array 30 in which a number of flaw detection coils 31 connected to a plurality of scanning lines are arranged in a matrix on a flexible printed circuit board can be rotated on a support shaft 20 via a bearing 12. A rotary eddy current flaw detector provided on an outer peripheral surface 11 of a rotating body 10 supported by an elastic body 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current flaw detector, and more particularly to an eddy current flaw detector capable of detecting a flaw without being affected by the shape and location of a flaw detection target.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8A, for example, an eddy current flaw used for detecting a flaw existing on a wall surface such as a pipe used for a gas pipe 51 is provided at a tip end of an actuating pin 82. Flaw detection probe 80 having flaw detection coil 81
Is inserted into the pipe hole 511 and moved to detect the inner wall of the pipe. Further, as shown in FIG. 8B, the flaw-detected body 52 is mounted on a rotatable chuck 53 and rotated, and the surface thereof is moved by the flaw-detecting probe 80 for flaw detection.

In such a flaw detection method, a positional relationship such as a contact angle and a distance between the flaw detection probe and the flaw detection target is required to be constant. Actuator control is required. In the flaw detection method as described in (A) above, the flaw detection probe 80 must have a shape and size corresponding to the shape and size of the tube hole 511 of the flaw-detected body 51, and it is difficult to use a general-purpose flaw detection probe. there were. Further, in the flaw detection method as shown in FIG. 4B, the flaw detection probe 80 can be installed only on the flaw-detected body 52 having a fixed shape, and particularly on a complicated curved surface or the like, the flaw detection probe 80 and the flaw detection target are used. Body 5
It was impossible to keep the positional relationship with the lens 2 constant, and it was impossible to reliably detect flaws. Further, when a structure or the like exists around the inspection object 52,
The place where the flaw detection probe is installed is limited.

[0004] Therefore, the above-described flaw detection method is very effective for inspection of, for example, pipes, axles, cans, etc. having a fixed shape. , It is necessary to design a flaw detection probe and an actuator for driving the flaw detection probe,
It increased costs and was rarely applied.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a flaw detection apparatus which can reliably and accurately detect a flaw in accordance with the shape of a body to be flawed.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an eddy current flaw detection method in which a plurality of flaw detection coils connected to a plurality of connection lines are arranged in a matrix on a flexible printed circuit board. The rotary eddy current flaw detection device is provided with a coil array on an outer peripheral surface of a rotating body rotatably supported on a support shaft via a bearing, and is capable of moving by contacting the surface of the flaw-detected body.

Further, according to the present invention, in the above-mentioned rotary eddy current flaw detector, an elastic body is arranged between the outer peripheral surface of the rotating body and the coil array for flaw detection to improve the contact property with the surface to be flaw-detected.
Further, the present invention provides the above-mentioned rotary eddy current flaw detector,
The rotating body was formed in a cylindrical shape, and the center axis of the support shaft was arranged coaxially with the rotating axis of the rotating body.

Further, according to the present invention, in the rotary eddy current flaw detection apparatus, the support shaft is provided with a selection output means for selecting and outputting the output of the flaw detection coil which comes into contact with the flaw detection object.

According to the present invention, in the above-mentioned rotary eddy current flaw detector, a rotation angle detecting means for detecting a rotation angle of a rotary body comprising a code plate attached to the rotary body and a rotary encoder having a detection means attached to a rotary support shaft. Is provided so that the output location of the detected signal can be recognized.

The present invention further provides an eddy current flaw detection coil array in which a plurality of flaw detection coils connected to a plurality of connection lines are arranged in a matrix on a flexible printed circuit board, and an endless endless coil having both ends connected. The rotary eddy current flaw detector has an infinite rail having a flexible strip and a support shaft for supporting the infinite rail, and the eddy current flaw detection coil array is arranged on the surface of the strip to form a rotary eddy current flaw detector. .

[0011]

As described above, according to the present invention, the flexible printed coil is used as the flaw detection coil and the elastic body is interposed on the back surface, whereby the adhesion between the flaw detection coil and the flaw detection object is improved, and the sensitivity is improved. And noise signals such as lift-off can be reduced.

Further, according to the present invention, a flaw detection coil array for eddy current flaw detection having a large number of flaw detection coils is arranged on the outer peripheral surface of a rotating body such as a roller, and the roller is rotated to detect flaws over the whole flaw-detected body. The present invention provides a rotary eddy current flaw detector capable of performing the following. In addition, the flaw detection coil arranged on the outer peripheral surface of the rotating body is continuously arranged on the entire outer peripheral surface of the rotating body, and by sequentially switching the flaw detecting coil with the rotation of the rotating body to take out the output. In addition, flaw detection can be performed throughout the range in which the flaw detection device travels. Further, by arranging the flaw detection coils in the direction of the rotation axis of the rotating body, it is possible to increase the width of flaw detection in one run.

By using a thin flaw detection coil manufactured on a printed circuit board, the diameter of the rotating body can be reduced, and the rotating body can be used even in a small space. By providing a rotary encoder on the rotating body,
The flaw detection position can be specified, and the flaw-detected portion can be mapped.

The rotator provided with the flaw detection coil is not limited to a cylindrical shape, but may be a rotator composed of elastically deformable parts or a rotator such as a caterpillar type. As a result, the flaw detection coil can be brought into surface contact with the flaw-detected body, so that a slip does not occur between the two during traveling, and an accurate position can be known.

Further, the present invention can also be used in a usage mode in which a rotary member is rotated by moving an object to be inspected, instead of moving a rotary flaw detector.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventors of the present invention have already made an invention relating to an eddy current flaw detection coil array in which a large number of flaw detection coils connected to a plurality of scanning lines are arranged in a matrix on a flexible printed circuit board. Filed (Japanese Patent Application No. 9-2)
09276).

The present invention relates to a rotary eddy current flaw detector using such a coil array for eddy current flaw detection. The configuration of the rotary eddy current flaw detector according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view illustrating the external structure of a rotary eddy current flaw detector according to the present invention. FIG. 2 is a front view showing the shape of the rotary eddy current flaw detector according to the present invention, and FIG. 3 is a top view showing the shape of the rotary eddy current flaw detector according to the present invention. FIG. 4 is a plan view schematically showing the shape of the eddy current flaw detection coil array used in the rotary eddy current flaw detector according to the present invention. FIG. 5 is a schematic diagram of an output extraction method for explaining an example of a method of extracting an output from a flaw detection coil of the rotary eddy current inspection device according to the present invention.

As shown in FIGS. 1 to 3, a rotary eddy current flaw detector 1 according to the present invention comprises a rotating body (roller) 10, a support shaft 20, and an eddy current flaw detection coil provided on the outer peripheral surface of the roller. An array 30 is provided.

The roller 10 is formed in a cylindrical shape and has an outer peripheral surface 11, a bearing 12, and a flange 13 connecting the outer peripheral surface 11 and the bearing 12. The support shaft 20 is a roller 1
The hand grip 21 is provided near the end opposite to the side supported by the bearing 12 and rotatably supported by the bearing 12. Further, a signal line for extracting a signal from the flaw detection coil is disposed inside the support shaft 20.
Has been pulled out to the outside.

As shown in FIG. 4, the eddy current flaw detection coil array 30 has a large number of flaw detection coils 31A-11, 31B-11-31A-8 on both sides of a flexible printed circuit board 32.
3, 31B-83 are arranged in a matrix. The flaw detection coil 31 is formed by spirally providing wiring on the surface of a flexible printed board 32. In this embodiment,
Eight flaw detection coils 31 are arranged in the circumferential direction of the roller 10 and are arranged in three rows in the axial direction of the roller 10. The number of the flaw detection coils 31 can be any number according to the required resolution and flaw detection width.

The flaw detection coils 31 in each row of the eddy current flaw detection coil array 30 are connected to one end of eight flaw detection coils 31 B provided on one surface of a flexible printed circuit board 32 via a common connection line 33. 35. One connection line 33 and one electrode 35 are provided for each row. Further, as for the flaw detection coils 31 of the eddy current flaw detection coil array 30, 24 flaw detection coils 31 A provided on the other surface of the flexible printed circuit board 32, one end of which is independent of each other via a connection line 34, respectively. Is connected to the electrode 36. 24 connection lines 34 and 24 electrodes 36 are provided. The other ends of the flaw detection coil 31A and the flaw detection coil 31B are connected to each other via a via hole 37.

The eddy current flaw detection coil array 30 is attached to the surface of the outer peripheral surface 11 of the roller 10 via an elastic body 15. The connection lines 33 and 34 of the eddy current flaw detection coil array 30 are connected to electrodes 35 and 36 and a sliding electrode described later provided on the bearing 12 via a signal line provided on the roller 11 and described later.

Hereinafter, an example of a method for extracting a signal from each of the eddy current detection coils 31 will be described with reference to the schematic diagram of FIG. FIG. 5 shows the configuration of the signal extracting means for extracting the outputs of the flaw detection coils 31A-1 to 31A-8 arranged in one row. In this embodiment, since the flaw detection coils 31 are arranged in three rows, three signal extraction means are also provided.

The roller 10 is provided with a plurality of sliding electrodes 16 provided inward so as to face signal extraction electrodes to be described later, and an insulator 17 provided between the sliding electrodes. The sliding electrodes 16 are provided corresponding to the number of the flaw detection coils 31. The sliding electrode 16 is configured to have a size that does not short-circuit the adjacent sliding electrodes 16-1 and 16-2, as shown in FIG. Further, the roller 10 is provided with three unillustrated slip rings corresponding to the connection lines 33 that connect the flaw detection coils 31B-1 to 31B-8, and the support shaft 22 includes illustrations corresponding to the slip rings. Are omitted and three signal extraction electrodes are provided.

Each of the flaw detection coils 31A-11, 31A-21... 31A-71, 31 in the first row of the eddy current flaw detection coil array 30 attached to the outer peripheral surface 11 of the roller 10.
Electrodes 36-11 and 36- connected to A-81, respectively.
21 ... 36-71, 36-81 are connected to the sliding electrodes 16-1, 16-2 ... 1 via the signal line 38 of the first signal extracting means.
6-7, 16-8. Similarly, each of the flaw detection coils 31A-12, 31A-22.
Electrodes 36-1 respectively connected to 72, 31A-82
2, 36-22... 36-72, 36-82 are connected to the sliding electrodes 16-1, 1 through the signal line 38 of the second signal extracting means.
6-2... 16-7, 16-8. As well. Each flaw detection coil in the third row is also connected to the sliding electrode of the third signal extracting means.

The first-row flaw detection coils 31B-11 to 31B-81 of the eddy-current flaw detection coil array 30 are connected to a first line (not shown) via a connection line 33-1 and an electrode 35-1.
Connected to a slip ring. Similarly, the coil for flaw detection 31 in the second row of the flaw detection coil array 30 for eddy current flaw detection
B-12 to 31B-82 are connected line 33-2, electrode 35
-2 is connected to a second slip ring (not shown). Similarly, the eddy current flaw detection coil array 3
0, 3rd line flaw detection coils 31B-13 to 31B-8
Reference numeral 3 is connected to a third slip ring (not shown) via a connection line 33-3 and an electrode 35-3.

On the surface of the support shaft 20, a signal extracting electrode 22
And an insulator 23 are provided, and a signal is extracted from the signal extraction electrode 22 to the outside via the signal line 24. One signal extraction electrode 22 is provided for each row. The signal extracting electrode 22 is provided at a position for extracting a signal from a flaw detection coil located at a flaw detection location of the flaw-detected body.

With such a configuration, the outputs of the three flaw detection coils 31 arranged in each row can be simultaneously extracted by using three signal extracting means and three slip rings.

By constructing the rotary eddy current flaw detector in this manner, as shown in FIG.
The flaw detection can be performed by rotating the roller 10 so as to scan over the flaw detection surface of the flaw-detected body 50. At this time, the output of the flaw detection coil 31 is output from the signal extraction electrode 22 via the signal line 24 and the connector 40 to a flaw detection control device (not shown) provided outside to inspect the flaw detection surface for flaws. be able to.

In order to know the position of the roller 10, that is, the position of the detected scratch, the roller 1
0, a disk-shaped code plate is attached and the support shaft 2
A rotary encoder can be provided by providing detection means including a light emitting diode and a phototransistor at 0. By providing such an encoder, it is possible to know the distance that the rotary eddy current flaw detection device 1 has moved on the surface of the flaw-detected body 50. Therefore, it is possible to map the flaw detection result and to know the location where the flaw exists. .

Referring to FIG. 7, the structure of a rotary eddy current testing apparatus according to a second embodiment of the present invention will be described. The rotary eddy current flaw detector 2 is characterized in that a flaw detection coil is provided on an infinite rail instead of the roller of the rotary eddy current flaw detector described above. The rotary type eddy current flaw detection device 2 includes an endless rail 6 made of an endless flexible band-shaped body connected at both ends.
0, an infinite orbital rail extending means 70 provided so that the infinite orbital rail 70 is in contact with the surface of the inspection object, and the support shaft 20.

The endless rail 60 is formed as an endless belt made of, for example, synthetic rubber, and has a front wheel 71-1 and a rear wheel 71-.
It is stretched between two. A coil array similar to the eddy current flaw detection coil array 30 used in the rotary eddy current detection device 1 is attached to the surface of the infinite rail 60, and flaw detection coils 31 are arranged.

In addition to the front wheel 71-1 and the rear wheel 71-2, the endless rail extension means 70 is provided with wheels 72 provided on a bogie 73, and the bogie 73 is rotatably mounted on a large bogie 74. ing. The bogie 73 and the large bogie 74 are urged by a spring (not shown) so as to function as an equalizer, and are configured so that the flaw detection coil 31 provided on the surface of the infinite rail 60 is pressed against the flaw detection surface. The output of each flaw detection coil 31 is extracted to the outside via signal extraction means (not shown).

According to this configuration, since the entire surface of the flaw detection coil 31 is in contact with the surface to be flawed, the flaw can be reliably detected.

In the first embodiment, the elastic body 15 is provided on the outer peripheral surface of the roller 10, but the roller itself may be made of an elastic material or have an elastic structure so that the roller 10 can be used at the time of flaw detection. Is deformed and the entire surface of the flaw detection coil contacts the surface to be flawed, so that flaw detection can be performed reliably.

[0036]

According to the present invention, the flaw detection probe is not attached to the flaw detection target, and the roller is manually rolled to detect the flaw. Therefore, any flaw detection target can be easily detected. be able to.

Further, since the roller is in close contact with the curved surface shape,
The flaw detection probe can be brought into close contact with the flaw detection target, and accurate flaw detection can be performed.

If an elastic member such as rubber is attached to the roller portion, the entire surface of the flaw detection coil can be pressed against the flaw detection object, and the influence of lift-off and the like can be avoided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the outline of the external configuration of a rotary eddy current flaw detector according to the present invention.

FIG. 2 is a front view illustrating the outline of the configuration of the rotary eddy current flaw detector shown in FIG. 1;

FIG. 3 is a top view for explaining the outline of the configuration of the rotary eddy current flaw detector shown in FIG. 1;

FIG. 4 is a plan view for explaining the outline of the shape of a flaw detection coil array used in the rotary eddy current flaw detection apparatus according to the present invention.

FIG. 5 is a schematic diagram for explaining the concept of a signal extracting means of the rotary eddy current flaw detector shown in FIG. 1;

FIG. 6 is a view showing a usage form of the rotary eddy current flaw detector according to the present invention.

FIG. 7 is a front view showing the outline of the configuration of a rotary eddy current testing apparatus according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a conventional eddy current flaw detection method.

DESCRIPTION OF SYMBOLS 1, 2 rotary eddy current testing device 10 roller 11 roller outer peripheral surface 12 bearing 13 flange 15 elastic body 16 sliding electrode 17 insulator 20 support shaft 21 hand grip 22 signal extraction electrode 23 insulator 24 signal line 30 Eddy current flaw detection coil array 31 Flaw detection coil 32 Flexible wiring board 33, 34 Connection line 35, 36 Electrode 37 Via hole 38 Signal line 40 Connector 50, 51, 52 Inspected object 60 Infinite rail 70 Infinite rail extension means 71 , 72 wheels 73 trolley 74 large trolley 80 probe for flaw detection 81 coil 82 actuator

Claims (8)

[Claims] An eddy current flaw detection coil array in which a number of flaw detection coils connected to a plurality of connection lines are arranged in a matrix on a flexible printed circuit board is rotatably supported on a support shaft via a bearing. A rotary eddy current flaw detection device provided on the outer peripheral surface of a rotating body. 2. The rotary eddy current flaw detection apparatus according to claim 1, wherein an elastic body is arranged between the outer peripheral surface of the rotating body and the coil array for eddy current flaw detection. 3. The rotary eddy current according to claim 1, wherein the rotating body has a cylindrical shape, and a center axis of a supporting shaft is arranged coaxially with a rotating axis of the rotating body. Flaw detector. 4. The rotary eddy current flaw detection apparatus according to claim 1, wherein an output means for taking out the output of the flaw detection coil is provided on the support shaft. 5. The rotary eddy current flaw detection apparatus according to claim 4, wherein the output means is a selection output means for selecting and taking out an output of a flaw detection coil which comes into contact with the flaw detection object. 6. The rotary eddy current testing device according to claim 1, further comprising a rotation angle detecting means for detecting a rotation angle of the rotating body. 7. The rotary eddy current flaw detector according to claim 6, wherein the rotation angle detecting means is a rotary encoder having a code plate attached to a rotating body and a detecting means attached to a rotation support shaft. . 8. An eddy current flaw detection coil array in which a large number of flaw detection coils connected to a plurality of connection lines are arranged in a matrix on a flexible printed circuit board, and an endless flexibility having both ends connected. A rotary eddy current flaw detection device, comprising: an infinite rail having a belt-like body having the same; and a support shaft for supporting the infinite rail, wherein the eddy current flaw detection coil array is arranged on a surface of the belt-like body.