JP6612692B2 - Eddy current flaw detection probe - Google Patents

Description

  The present invention relates to an eddy current flaw detection probe for detecting a defect of an inspection object nondestructively using eddy current.

  When a coil carrying an alternating current is placed near the conductive object to be inspected (test body), the alternating magnetic flux generated in the coil passes through the inside of the specimen and eddy current is induced inside the specimen by electromagnetic induction. The The eddy current flaw detection inspection indirectly detects changes in the test specimen (defects such as cracks, scratches, and holes) by monitoring (monitoring) changes in the impedance generated in the coil due to the eddy current generated inside the specimen. This is a possible inspection (test) method.

  Patent Document 1 discloses an eddy current flaw inspection probe and a eddy current flaw inspection method for nondestructively inspecting the presence or absence of defects such as a flaw in a copper heat transfer tube constituting a heat exchanger.

JP 2003-294711 A

  In recent years, there are cases in which a railway vehicle structure is manufactured with a hollow extruded shape member made of an aluminum alloy for the purpose of improving the quality by reducing the interior noise and reducing the cost by reducing the number of parts. The hollow extruded shape member is a member made of an aluminum alloy including two facing face plates and ribs (end ribs and internal ribs) connecting the face plates. A plurality of hollow extruded sections are arranged and joined on a surface plate to produce panels such as a base frame forming a floor surface of a railway vehicle structure, a side structure forming a side surface, a roof structure forming a roof, and the like. Manufactured by assembling into a face piece.

  The hollow extruded shape member is composed of a pair of face plates, end ribs located at both ends in a direction crossing the extrusion direction, and a plurality of internal ribs provided in a region surrounded by the face plates and the end ribs. The soundness of the face plate and the end rib can be confirmed visually or by palpation (percussion), but it is very difficult to confirm the soundness of the internal rib that is not exposed to the outside.

  An object of the present invention is to provide a probe for eddy current flaw detection that can inspect the soundness of the internal rib of a hollow extruded profile with a small number of inspection steps and high accuracy without increasing the type and number of eddy current flaw detection probes. It is to be.

  An eddy current flaw detection probe according to an embodiment of the present invention is for flaw detection of a rib of a hollow extruded shape member having two facing face plates and a plurality of ribs connecting the face plates. The first coil holding part and the second coil holding part having a substantially rectangular parallelepiped shape are provided, and the first coil holding part and the second coil holding part are placed on the rib during the flaw detection inspection. One or more coils formed by winding a copper wire are wound around each of the first coil holding part and the second coil holding part, and the first long side of the first coil holding part and the second coil The first long side of the holding portion is coupled to be rotatable about the first long side as an axis.

  ADVANTAGE OF THE INVENTION According to this invention, the soundness of the internal rib of a hollow extrusion profile can be test | inspected with few inspection steps and high precision, without increasing the kind and number of probes for an eddy current test.

FIG. 1 is a plan view of the eddy current flaw detection probe according to the first embodiment. FIG. 2 is a diagram (corresponding to AA in FIG. 1) of the eddy current flaw detection probe according to the first embodiment viewed from the longitudinal direction. FIG. 3 is a schematic diagram illustrating a state in which a defect portion of the hollow extruded shape member is detected with the eddy current flaw detection probe according to the first embodiment. FIG. 4 is a cross-sectional view (corresponding to the cross section in FIG. 3B-B) intersecting with the longitudinal direction of the hollow extruded profile being flaw-detected by the probe for eddy current flaw detection according to the first embodiment. FIG. 5 is a cross-sectional view (corresponding to the cross section of FIG. 3B-B) intersecting with the longitudinal direction of the hollow extruded profile during flaw detection by the eddy current flaw detection probe according to the second embodiment.

  Several embodiments of the present invention will be described below with reference to the drawings. First, each direction used for description is defined. In each drawing, arrows 100, 110, and 120 are shown. The arrow 100 represents the longitudinal direction of the eddy current flaw detection probe and the hollow extruded profile to be inspected. It is written as “longitudinal direction 100”. The arrows 110 and 120 represent the width direction and the thickness (height) direction of the eddy current flaw detection probe and the hollow extruded profile, respectively. The height (height) direction 120 ”.

  First, the configuration of the eddy current flaw detection probe according to the first embodiment and the flaw detection method for defects in the internal ribs of the hollow extruded profile using the eddy current flaw detection probe will be described. FIG. 1 is a plan view of an eddy current flaw detection probe 50 according to the first embodiment, and FIG. 2 is a view of the eddy current flaw detection probe 50 as viewed from the longitudinal direction 100 (corresponding to AA in FIG. 1). . The eddy current flaw detection probe 50 detects flaws in the internal ribs of a hollow extruded shape member made of an aluminum alloy having a plurality of ribs that connect two opposing face plates and the double face plates (FIG. 3, FIG. 3). 4).

  The eddy current flaw detection probe 50 includes a coil holding portion 1a around which the coil 2a (2b) is wound and a coil holding portion 1b around which the coil 3a (3b) is wound. The coil holding portion 1a (1b) has a substantially rectangular parallelepiped member having a long side along the longitudinal direction 100 and a short side along the width direction 110, and a width direction 110 from a part of the long side of the member. It has the overhang | projection part 5a (5b) which protrudes toward. The coil 2a (2b, 3a, 3b) is formed by winding a copper wire one or more times in the width direction 110 of the coil holding portion 1a (1b).

  Although details will be described later, when the flaw detection of the internal rib of the hollow extruded shape member is performed using the eddy current flaw detection probe 50 according to the present embodiment, the long side of the coil holding portion 1a (1b) One of the short sides (two surfaces) is placed so as to face the internal rib. In the present specification, this surface is referred to as a “bottom surface”, and conversely, the surface that is not the bottom surface among the long and short sides of the coil holding portion 1a (1b) is referred to as a “top surface”.

  The overhanging portion 5a of the coil holding portion 1a and the overhanging portion 5b of the coil holding portion 1b are each provided with a hole penetrating along the longitudinal direction 100. As shown in FIG. 1, the overhanging portion 5a and the overhanging portion 5b are arranged in series between the long side of the coil holding portion 1a having the overhanging portion 5a and the long side of the coil holding portion 1b having the overhanging portion 5b. In a state of being opposed to each other, the linear shaft portion 10 is passed through the holes provided in the overhanging portion 5a and the overhanging portion 5b. As a result, the coil holding portion 1a and the coil holding portion 1b are coupled, and the coil holding portion 1a and the coil holding portion 1b are configured to be rotatable about the long side (more precisely, about the shaft portion 10).

  A washer 14 and a nut 12 are attached to both ends of the shaft portion 10, and the nut 12 is tightened to such an extent that the coil holding portion 1 a and the coil holding portion 1 b can rotate around the shaft portion 10. However, if necessary, the nut 12 may be tightened so that the coil holding part 1a and the coil holding part 1b do not rotate. With this configuration, a deployment angle (hereinafter referred to as an angle) θ1 (see FIG. 2) formed by the coil holding portion 1a and the coil holding portion 1b can be maintained at an arbitrary angle in the range of 75 to 180 degrees.

  A groove (not shown) is provided in a plane intersecting the longitudinal direction 100 at a portion where the coil 2a (2b) of the coil holding portion 1a is wound, and the coil 2a (2b) is wound around the groove. The coil 2b is wound around the coil holding part 1a at a predetermined interval in the longitudinal direction 100 from the coil 2a. The same applies to the coil 3a (3b) wound around the coil holding portion 1b. The coil holding part 1a (1b) is comprised from resin etc. which have a low relative magnetic permeability (or magnetic susceptibility).

  At the end of the coil holding portion 1a (1b) in the longitudinal direction 100, a terminal 3 or the like that supplies an alternating current to the coil 2a or the like via a cable 40 (see FIG. 3) described later is provided. Further, on the bottom surface of the coil holding portion 1a (1b), the coil holding portion 1a (1b) can smoothly move on the inspection surface of the internal rib and suppress a disturbance (rare signal) caused by vibration during flaw detection. Plungers 6 (friction reduction members) are provided discretely.

  In addition, a plurality of (for example, two) cable holding portions 7 are discretely provided along the longitudinal direction 100 on the upper surface of the coil holding portion 1b. In addition, a plurality of terminals 3 for applying an alternating current to the coil 2a and the like, and a terminal protector 8 are arranged in the longitudinal direction 100 on the end face of one end in the longitudinal direction 100 of the coil holding part 1a (1b). It protrudes. The dimension of the terminal protection part 8 in the longitudinal direction 100 is set larger than that of the terminal 3, and the terminal protection part 8 protrudes larger than the terminal 3. In FIG. 1, one terminal protection unit 8 is provided in each of the coil holding unit 1a and the coil holding unit 1b, but a plurality of terminal protection units 8 may be provided.

  Since the terminal protection unit 8 is configured to protrude larger than the terminal 3, the terminal protection unit 8 collides before the connection portion between the terminal 3 and the signal line 4 collides with an object to be inspected. The connection can be protected. Moreover, each cable holding part 7 is provided with the hole penetrated along the longitudinal direction 100, and the cable 40 which bundled the signal wire | line 4 is provided in the aspect penetrated to the hole of each cable holding part 7, and is long. The coil holding portion 1b is provided along the direction 100.

  FIG. 3 is a schematic view showing a state in which a defect portion of a hollow extruded shape member is flawed by an eddy current flaw detection probe, and FIG. 4 is a diagram in the longitudinal direction 100 of the hollow extruded shape member being flawed by the eddy current flaw detection probe. It is sectional drawing which cross | intersects (equivalent to the cross section of FIG. 3B-B).

  A hollow extruded profile 30 made of an aluminum alloy to be inspected has a first face plate 32a and a second face plate 32b facing each other, end ribs 34 connecting the face plates, internal ribs 35a to 35c, and the like. In the typical hollow extruded shape shown in FIG. 4, the internal rib 35a adjacent to the end rib 34 is connected to the first face plate 32a at an angle θa, and the internal rib 35a and the internal rib 35b are connected at an angle θb. The

  Since the total length L (the dimension in the longitudinal direction 100) of the hollow extruded shape member 30 used for the panel constituting the structure of the railway vehicle ranges from 20 to 26 m, the first face plate 32a, the second face plate 32b, the hollow extruded shape member Inspect for defects 77 (see FIG. 4) such as cracks and voids generated in the plurality of internal ribs 35a to 35c included in the region surrounded by the end ribs 34 located at the end portions in the width direction 110 of 30. Was very difficult.

  A state in which the presence / absence of a defect occurring in the internal rib 35a of the hollow extruded shape member 30 by the eddy current flaw detection probe 50 according to the present embodiment will be described. Below, the case where the presence or absence of the defect which arose in the internal rib 35a and the internal rib 35b is test | inspected as an example is demonstrated. First, the angle θ1 between the coil holding part 1a and the coil holding part 1b constituting the eddy current flaw detection probe 50 is substantially equal to the angle θb between the internal rib 35a and the internal rib 35b of the hollow extruded profile 30 to be inspected. In accordance with the same angle, the bottom surface of the coil holding portion 1a (1b) faces the internal rib 35a (35b) through the ball plunger 6. If necessary, the nuts 12 provided at both ends of the shaft portion 10 are tightened to hold the angle between the coil holding portion 1a and the coil holding portion 1b at a predetermined angle θ1.

  An eddy current flaw detection probe 50 held in a state where the coil holding portion 1a and the coil holding portion 1b are deployed at an angle θ1 is connected to internal ribs 35a and 35b at one end in the longitudinal direction 100 of the hollow extruded profile 30. It is placed on the top surface. Subsequently, an AC current is applied to the coil 2a (2b, 3a, 3b) provided in the coil holding portion 1a (1b) via the cable 40, and the cable 40 connected to the eddy current flaw detection probe 50 is connected. By pulling and moving the probe 50 for eddy current flaw detection, an eddy current flaw inspection is performed on the impedance change between the end in one longitudinal direction 100 of the hollow extruded profile 30 and the end in the other longitudinal direction 100. The measurement is performed with the probe 50.

  Since the probe 50 for eddy current flaw detection is configured such that the angle θ1 between the coil holding portion 1a and the coil holding portion 1b can be varied, two adjacent (one pair) internal ribs of the hollow extruded profile to be inspected For example, a defective portion 77 (see FIG. 4) generated in the internal rib 35a and the internal rib 35b is utilized by using a response difference between the coils 2a (3a) and 2b (3b) provided adjacent to the coil holding portion 1a (1b). Since the flaw can be detected in one process by the self-comparison method, the inspection process can be shortened.

  Furthermore, according to the above configuration, the angle θ1 between the coil holding part 1a and the coil holding part 1b can be changed according to the angle θb formed by the pair of adjacent internal ribs. Can be inspected using the eddy current flaw detection probe 50 for hollow extruded profiles of different types (with different θb). Therefore, the versatility of the eddy current flaw detection probe 50 according to the present embodiment is high, and the cost required for the inspection can be reduced.

  Furthermore, according to the above configuration, the angle θ1 between the coil holding portion 1a and the coil holding portion 1b can be adjusted to the angle θb formed by the pair of adjacent internal ribs, so that the surface of the internal rib 35a and the like and the coil holding portion 1a ( The surfaces of 1b) can be arranged substantially parallel. For this reason, a highly accurate flaw detection test using the eddy current flaw detection probe 50 can be performed.

  Further, since the ball plungers 6 are discretely provided in the coil holding portion 1a (1b), the eddy current flaw detection probe 50 can be smoothly moved in the longitudinal direction 100 of the hollow extruded profile 30. Furthermore, since the gap (gap) between the coil holding portion 1a (1b) and the inspection surface such as the internal rib 35a can suppress lift-off (disturbance) that changes during scanning of the eddy current flaw detection probe 50, disturbance (disturbance) High flaw detection accuracy can be obtained by reducing (noise).

  Further, for example, when the soundness of one of the internal rib 35a and the internal rib 35b (for example, the internal rib 35a) can be confirmed, the internal rib 35a is used as a reference body, and the internal rib 35b adjacent to the internal rib 35a is used. It is possible to carry out a flaw detection inspection by a standard comparison method as an inspection object. In this case, the coil holding part 1a may have a configuration in which only one coil (only the coil 2a or only the coil 2b) is provided. Similarly, the coil holding portion 1b may be provided with only one coil (only the coil 3a or only the coil 3b).

  Subsequently, an eddy current flaw detection probe according to the second embodiment will be described. FIG. 5 is a cross-sectional view that intersects the longitudinal direction 100 of the hollow extruded profile being flaw-detected by the eddy current flaw detection probe 52 according to the second embodiment (corresponding to the cross-section of FIG. 3B-B). In the second embodiment, among the configurations of the eddy current flaw detection probe 52 according to the second embodiment, the description of the configuration common to the eddy current flaw detection probe 50 described in the first embodiment is omitted, and the first embodiment is omitted. And the new effects that are derived from it.

  The eddy current flaw detection probe 52 includes a pair of coil holding portions 1a (1b), and measures the shape of the end portion in the width direction 110 opposite to the shaft portion 10 of the coil holding portion 1a (1b). The angle θ2 is substantially the same as the angle θa formed by the first face plate 32a of the target hollow extruded profile 30 and the internal rib 35a (35b). That is, as the thickness dimension of the coil holding portion 1a (1b) moves away from the shaft portion 10 in the width direction 110, the shape of the coil holding portion 1a (1b) near the long side opposite to the shaft portion 10 is increased. By gradually reducing the coil holding portion 1a (1b) when viewed from the longitudinal direction 100, this portion has an acute angle θ2.

  Since the eddy current flaw detection probe 52 according to the second embodiment has such a configuration, the coil holding portion 1a (1b) having substantially the same dimension as the dimension W1 in the width direction 110 of the internal rib 35a and the like to be inspected is provided. Can be prepared. Therefore, in addition to the effects described in the first embodiment, the eddy current flaw detection probe 52 according to the second embodiment can detect the defect portion 77 in the range of the entire width dimension W1, such as the internal rib 35a. For this reason, since a wider range of internal ribs 35a and the like can be detected with a smaller number of inspection steps, a higher-quality inspection result can be obtained.

1a, 1b ... coil holding part, 2a, 2b, 3a, 3b ... coil,
6 ... ball plunger (roller type), 10 ... shaft,
12 ... Fixing device (nut), 14 ... Washer (plain and spring washer),
30 ... Hollow extruded profile,
32a ... first face plate, 32b ... second face plate,
34 ... end ribs, 35a, 35b ... internal ribs,
50, 52 ... Probe for eddy current inspection, 77 ... Defect,
θa: Angle formed by the first face plate of the hollow extruded profile and the internal rib,
θb: Angle formed by adjacent internal ribs of the hollow extruded profile,
θ1 ... Deployment angle of probe for eddy current inspection,
θ2: Inclination angle of coil holding portion in width

Claims (8)

An eddy current flaw detection probe for flaw detection inspection of the rib of a hollow extruded shape member having a plurality of ribs connecting two facing face plates,
The eddy current flaw detection probe is:
The first coil holding part and the second coil holding part having a substantially rectangular parallelepiped shape, which are placed on the rib during the flaw detection inspection of the rib,
Around each of the first coil holding part and the second coil holding part, one or more coils formed by winding a copper wire are wound,
The first long side of the first coil holding part and the first long side of the second coil holding part are coupled so as to be rotatable about the first long side.
An eddy current flaw detection probe characterized by that. The first coil holding part has a first overhanging part protruding in a width direction from a part of the first long side of the first coil holding part,
The second coil holding part has a second projecting part that projects in the width direction from a part of the first long side of the second coil holding part,
Each of the first overhanging portion and the second overhanging portion is provided with a hole penetrating along the longitudinal direction of the first or second coil holding portion,
The eddy current flaw detection probe further includes a shaft portion for coupling the first coil holding portion and the second coil holding portion,
The shaft portion opposes the first long side of the first coil holding portion and the first long side of the second coil holding portion, and the first overhanging portion and the second overhanging portion. Are arranged so as to penetrate through the holes provided in the first overhanging portion and the second overhanging portion.
The eddy current flaw detection probe according to claim 1, wherein The probe for eddy current flaw inspection has an expansion angle formed by the first coil holding portion and the second coil holding portion by means of fixtures provided at both ends of the shaft portion, and the two ribs to be inspected. Configured to be fixed at an angle equal to the angle formed by
The probe for eddy current flaw detection according to claim 2, wherein: Friction reducing members are provided on the bottom surfaces of the first coil holding part and the second coil holding part,
The eddy current flaw detection probe according to any one of claims 1 to 3, wherein The friction reducing member is a ball plunger, and a plurality of the ball plungers are discretely provided on the bottom surfaces of the first coil holding portion and the second coil holding portion.
The probe for eddy current flaw detection according to claim 4, wherein A terminal for passing a current to the coil and a terminal protection part are provided at the longitudinal ends of the first coil holding part and the second coil holding part,
The terminal protection part projects larger in the longitudinal direction than the terminal,
The eddy current flaw detection probe according to any one of claims 1 to 5, wherein The first coil holding part and the second coil holding part are
The shape in the vicinity of the second long side, which is the long side opposite to the first long side of the first coil holding part and the second coil holding part, is directed away from the first long side. The probe for eddy current flaw detection according to any one of claims 1 to 6, wherein the probe has an acute angle with a gradually decreasing thickness dimension. The acute angle is
The probe for eddy current flaw detection according to claim 7, wherein the probe is an angle formed by the face plate and the rib.

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