KR102265940B1 - Cable defect inspection apparatus - Google Patents

Abstract

The present invention relates to a cable defect inspection device, which is disposed parallel to a central axis of a cable, a first magnetizing yoke including a first yoke bar provided with a coil sensor, is disposed parallel to the first yoke bar, and has a hall sensor A second magnetization yoke including a second yoke bar, which is connected to a yoke core forming both ends of the first magnetization yoke and the second magnetization yoke, may include a permanent magnet disposed adjacent to the cable. In this case, the second yoke bar may be formed to have a thinner thickness than the first yoke bar.

Description

CABLE DEFECT INSPECTION APPARATUS

The present invention relates to a cable defect inspection apparatus, and more particularly, it can be applied to various cables such as a cable for a bridge as well as a wire rope, and it is possible to detect a decrease in the cross-sectional area of a cable and detect a defect characteristic through effective magnetization of the cable. It relates to a cable defect inspection device.

Republic of Korea Patent Publication No. 10-1192286 is a device for measuring the volume loss of a wire rope and defects caused by cutting, abrasion, corrosion, and other external shocks. Instead of winding the coil directly on the wire rope, it is wound on a magnetizing yoke. It is a technology to detect loss of metallic cross-section area (LMA) by using a coil sensor.

1, the above-described wire rope defect detection device 10 is a magnetization yoke 3 for magnetizing the wire rope 1, a permanent magnet 5, a signal according to the total amount of magnetic force lines passing through the magnetized wire rope The output coil sensor 4 is included as a main configuration. The magnetization yoke 3 and the permanent magnet 5 are arranged to surround the wire rope 1 , and the coil sensor 4 is arranged in one region of the iron core constituting the magnetization yoke 3 .

1, when the wire rope defect detection device 10 is installed on the wire rope 2, a magnetic force line is generated by the permanent magnet 5, and the magnetic force line is a magnetizing yoke 3 and a magnetized wire rope (2) traverses the closed-curve path formed by At this time, the coil sensor 4 disposed on the magnetization yoke 3 may detect a change in magnetic flux density to detect whether defects such as voids and corrosion exist in the wire rope 2 .

However, since the coil sensor of the conventional wire rope defect detection device detects a change in magnetic flux density, it has no choice but to detect only the start point and the end point of a defect generated by cracks, corrosion, etc. generated in the wire rope. Therefore, in the conventional coil sensor of the wire rope defect detection apparatus, it is difficult to clearly distinguish whether the defects are formed continuously along the axial direction of the wire rope or sporadically along the axial direction of the wire rope.

That is, the conventional wire rope defect detection apparatus can accurately detect a decrease in the cross-sectional area of a wire rope, but has a disadvantage in that it is difficult to accurately detect the characteristics of the defect, such as the shape of the defect generated by cracks, corrosion, and the like. In addition, since the conventional wire rope defect detection device requires considerable weight because the material and arrangement of components are not optimized, it is difficult to use by being mounted on various cables having an inclined arrangement, such as a cable for a bridge, in addition to the wire rope. There is this.

Republic of Korea Patent Publication No. 10-1192286 (2012.10.17)

The present invention is to improve the disadvantages as described above, and by distributing and sensing a magnetic force line passing through a cable, it is an object of the present invention to provide an apparatus capable of easily and accurately detecting the characteristics of a defect, such as a shape of a defect occurring in the cable. have.

In addition, it is possible to reduce the overall weight and volume by optimizing the material and weight of the components, and to provide a defect detection device that can be easily mounted on various cables such as wire ropes as well as bridge cables. .

Cable defect inspection apparatus according to an embodiment of the present invention is arranged parallel to the central axis of the cable, a first magnetizing yoke including a first yoke bar provided with a coil sensor, is arranged in parallel with the first yoke bar, a hall sensor A second magnetization yoke including a second yoke bar provided with may include a permanent magnet connected to a yoke core forming both ends of the first magnetization yoke and the second magnetization yoke and disposed adjacent to the cable. In this case, the second yoke bar may be formed to have a thinner thickness than the first yoke bar.

A gap is provided in the second yoke bar according to an embodiment of the present invention to prevent saturation of the Hall sensor, and the Hall sensor may be disposed inside the gap.

The void according to an embodiment of the present invention may be formed in a shape of opening an upper part of the second yoke bar so that the Hall sensor is exposed to the outside, or formed inside the second yoke bar so that the Hall sensor is not exposed to the outside. have.

The width of the gap according to an embodiment of the present invention may be determined by considering at least one of the thickness of the second yoke bar and the type of the Hall sensor.

An electromagnetic field shielding layer for preventing saturation of the Hall sensor is provided on the second yoke bar according to an embodiment of the present invention, and the Hall sensor is disposed behind the electromagnetic field shielding layer based on the direction of magnetic flux generated by the permanent magnet can be

According to an embodiment of the present invention, a defect characteristic of a cable may be estimated based on a voltage corresponding to a time change amount of the magnetic flux density measured by the coil sensor and the magnetic flux density measured by the hall sensor.

The first magnetization yoke, the second magnetization yoke, and the permanent magnet according to an embodiment of the present invention may be integrally disposed in a radial shape at equal intervals along the circumferential direction of the cable.

Cable defect inspection apparatus according to an embodiment of the present invention may further include a coil sensor or a hall sensor disposed adjacent in the circumferential direction of the cable in order to detect a local defect of the cable.

According to the defect inspection apparatus provided as an embodiment of the present invention, by measuring the instantaneous change of magnetic flux density and magnetic flux density together through the magnetizing yoke structure that distributes the magnetic force line passing through the cable, the shape of the defect that could not be grasped in the conventional apparatus It is possible to easily and accurately detect the intrinsic characteristics of defects, such as.

In addition, it can be used to detect defects in various cables such as bridge cables that could not be used in conventional devices as well as wire ropes through weight reduction by optimizing the material, weight, etc. of the above-described magnetizing yoke structure and components, so higher utilization compared to the prior art and convenience.

1 is a longitudinal cross-sectional view showing a state of use of an existing device developed for detecting defects in a wire rope.
Figure 2 is a longitudinal cross-sectional view showing the use state of the cable defect inspection apparatus according to an embodiment of the present invention.
3 and 4 are a perspective view of a cable defect inspection apparatus and an enlarged view of a second magnetizing yoke according to an embodiment of the present invention.
5 is a graph comparing the sensor response of the conventional wire rope defect detection apparatus and the cable defect inspection apparatus according to an embodiment of the present invention.
6 is a longitudinal cross-sectional view showing the use state of the cable defect inspection apparatus according to an embodiment of the present invention.
7 is a cross-sectional view showing a use state of the cable defect inspection apparatus according to an embodiment of the present invention.

Terms used in this specification will be briefly described, and the present invention will be described in detail.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

In the entire specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated. Also, throughout the specification, when a part is "connected" with another part, this includes not only the case of being "directly connected" but also the case of being connected "with another configuration in between".

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a longitudinal cross-sectional view showing the use state of the cable defect inspection apparatus 100 according to an embodiment of the present invention.

The cable defect inspection apparatus 100 according to an embodiment of the present invention detects the cross-sectional area loss and the defect 2 of the cable 1 using the reluctance or total manetic flux monitoring method of the inspection object. It is a sensing device. 2, the cable defect inspection apparatus 100 is disposed parallel to the central axis of the cable 1, the first magnetizing yoke including the first yoke bar 111 provided with the coil sensor 112 ( 110), the second magnetization yoke 120 and the first magnetization yoke 110, which are disposed parallel to the first yoke bar 111 and include a second yoke bar 121 provided with a hall sensor 122, and The second magnetization yoke 120 may include a permanent magnet 140 connected to the yoke core 130 forming both ends and disposed adjacent to the cable (1).

The first magnetization yoke 110 and the second magnetization yoke 120 may form a closed circuit of lines of magnetic force generated by the permanent magnet 140 together with the cable 1 to be inspected. At this time, since the total amount of magnetic force lines generated by the permanent magnet 140 is constant, the first magnetizing yoke 110 and the second magnetic force line according to the thickness ratio of the first yoke bar 111 and the second yoke bar 121 are constant. It can be distributed to the magnetization yoke 120 and flow.

For example, when the second yoke bar 121 is formed to have a relatively thin thickness compared to the first yoke bar 111 , most of the magnetic force lines generated by the permanent magnet 140 are directed to the first magnetizing yoke 110 . flow, and only the remaining part flows to the second magnetization yoke 120 . That is, when the first yoke bar 111 and the second yoke bar 121 have a thickness ratio of 9:1, the magnetic force lines are the first magnetization yoke 110 and the second magnetization yoke 120 in a ratio of 9:1. can be distributed and flowed.

The coil sensor 112 provided on the first yoke bar 111 of the first magnetizing yoke 110 may measure a voltage (i.e. induced electromotive force) corresponding to a time change amount of the magnetic flux density. That is, when there is a defect 2 such as corrosion in the cable 1, the magnetoresistance value of the defective area 2 is different from the normal area of the cable 1, so that the cable defect inspection apparatus 100 determines the cable 1 ), the coil sensor 112 may detect an instantaneous change in the total amount of magnetic flux generated in the process of moving the defective region 2 as a defect signal. At this time, so that the coil sensor 112 of the first magnetizing yoke 110 can detect most of the magnetic force lines generated by the permanent magnet 140 as shown in FIG. 2 as a main sensor, the first yoke bar 111 is the first 2 It may be manufactured to have a relatively thick thickness compared to the yoke bar 121 .

The Hall sensor 122 provided on the second yoke bar 121 of the second magnetization yoke 120 may directly measure the magnetic flux density of the closed circuit passing through the second magnetization yoke 120 . That is, unlike the above-described coil sensor 112 , the hall sensor 122 detects the change in the total magnetic flux itself generated in the process of the cable defect inspection apparatus 100 moving the defective area 2 along the cable 1 . It can be detected as a defect signal. At this time, as shown in FIG. 2 , since the first yoke bar 111 is manufactured to have a relatively thicker thickness than the second yoke bar 121 , the Hall sensor 122 of the second magnetization yoke 120 is formed by the second magnetization yoke ( 120) can operate as a sub-sensor that detects only a part of the magnetic field lines distributed by FIG.

According to an embodiment of the present invention, the defect characteristic of the cable 1 is based on the voltage corresponding to the time change amount of the magnetic flux density measured by the coil sensor 112 and the magnetic flux density measured by the hall sensor 122 . can be estimated. Since the coil sensor 112 measures the amount of time change, it provides a detection signal sensitive to an instantaneous change, and the Hall sensor 122 directly measures the magnetic flux density, so a detection signal advantageous for inferring the shape of the defect 2 is provided. to provide. That is, unlike the conventional apparatus using only the coil sensor 4 , the cable defect inspection apparatus 100 according to an embodiment of the present invention can utilize the coil sensor 112 and the Hall sensor 122 together, thereby reducing the cross-sectional area. , it is possible to detect not only the location of the defect 2 but also characteristics such as the shape of the defect 2 .

3 and 4 are a perspective view of the cable defect inspection apparatus 100 and an enlarged view of the second magnetizing yoke 120 according to an embodiment of the present invention.

The Hall sensor is saturated and does not operate when exposed to a magnetic field having a relatively large size due to its own characteristics. For example, if the Hall sensor is simply attached to the branched magnetization yoke to connect the permanent magnets 140 , there is a high possibility that the Hall sensor will not operate under the influence of a magnetic field flowing along the magnetization yoke. Accordingly, when the Hall sensor is disposed on the magnetization yoke, a design capable of operating as a sensor while reducing the influence of a magnetic field is required.

As a design method for preventing the Hall sensor 122 from being saturated, a gap 123 may be provided in the second yoke bar 121 according to an embodiment of the present invention. In the area of the air gap 123 , the magnetic flux is reduced by the air layer inside the air gap 123 , so that only a portion of the magnetic flux passing through the area in which the air gap 123 is not formed may be detected through the Hall sensor 122 . That is, since the magnetic force line flowing along the second yoke bar 121 becomes weak in the region of the void 123, the Hall sensor 122 is disposed inside the void 123 formed in the second yoke bar 121, An environment in which the Hall sensor 122 can operate within a normal range may be provided.

For example, the gap 123 may be formed in a shape of opening a portion of the upper portion of the second yoke bar 121 so that the hall sensor 122 is exposed to the outside as shown in FIG. 3A . Also, the gap 123 may be formed inside the second yoke bar 121 so that the hall sensor 122 is not exposed to the outside as shown in FIG. 3B . The Hall sensor may be stably disposed on the second magnetization yoke 120 while effectively preventing the Hall sensor 122 from being saturated through the gap 123 .

Meanwhile, the width of the gap 123 may be determined by considering at least one of the thickness of the second yoke bar 121 and the type of the Hall sensor 122 . As the width of the gap 123 increases, the air layer inside the gap 123 increases, so that the magnitude of the magnetic field affecting the operation of the Hall sensor 122 is reduced. Accordingly, the width of the gap 123 may be designed in consideration of the performance of the Hall sensor 122 and the physical thickness of the second yoke bar 121 .

As a design method for preventing the Hall sensor 122 from being saturated, the second yoke bar 121 according to an embodiment of the present invention has an electromagnetic field shielding layer 124 for preventing the Hall sensor 122 from being saturated. can be provided. In this case, the Hall sensor 122 may be disposed behind the electromagnetic field shielding layer 124 based on the direction of the magnetic flux generated by the permanent magnet 140 . That is, since the electromagnetic field shielding layer 124 shields a portion of the magnetic field approaching from the front of the Hall sensor, the magnitude of the magnetic field affecting the operation of the Hall sensor 122 may be reduced. The Hall sensors 122 may be disposed adjacently to the rear of the electric field shielding layer as shown in FIG. 4 , or may be disposed spaced apart from each other by a predetermined interval.

In addition to the above design methods, by changing the material itself of the second yoke bar 121 to a metal having low permeability compared to iron, rather than changing the structural shape of the second yoke bar 121, the second yoke The saturation of the Hall sensor 122 can be prevented by lowering the total magnetic flux itself flowing through the bar 121 . That is, the second yoke bar 121 according to an embodiment of the present invention may be formed of a metal material having a lower magnetic permeability than iron.

5 is a graph comparing the sensor response of the conventional wire rope defect detection apparatus and the cable defect inspection apparatus 100 according to an embodiment of the present invention.

Referring to (a) of Figure 5, the conventional wire rope defect detection device 10 is the starting point and the end point of the defect (2) in the process of moving the cable (1) to be inspected as the response change of the coil sensor (4) can be detected. Since the coil sensor 4 measures the amount of time change of the magnetic force line by the defective area 2, the conventional wire rope defect detection device 10 is difficult to distinguish the number and shape of the defective area 2 within the measurement error range. It is difficult. For example, if there are two fine defect areas at positions corresponding to the start and end points of the defect, the response by the coil sensor 4 will be the same as that of FIG. 5 (a), so the conventional wire rope defect detection The device 10 cannot clearly distinguish characteristics such as the number and shape of defective areas.

On the other hand, referring to FIG. 5B , the cable defect inspection apparatus 100 according to an embodiment of the present invention includes a coil sensor 112 and a hall sensor 122 in the process of moving the cable 1 to be inspected. It is possible to detect characteristics such as the number and shape of the defects 2 as well as the start and end points of the defects 2 by changing the response of . Since the hall sensor 122 can detect the change in magnetic flux density itself due to the defect 2 , the number and shape of the defective area 2 , which was difficult to distinguish by the coil sensor 112 , can be easily distinguished and detected. . For example, when there are two fine defect regions at positions corresponding to the start and end points of the defect, the response by the coil sensor 112 is the same as that of FIG. 5 ( b ), but by the Hall sensor 122 . Since the response will be detected according to the location of the defective area, the cable defect inspection apparatus 100 can clearly distinguish characteristics such as the number and shape of the defective area.

6 is a longitudinal cross-sectional view showing the use state of the cable defect inspection apparatus 100 according to an embodiment of the present invention, Figure 7 is a cross-sectional view.

Referring to FIG. 6 , the cable defect inspection apparatus 100 according to an embodiment of the present invention may move the inclined cable 1 by circumscribing the cable 1 . Unlike the existing wire rope defect detection device, the components that do not affect the generation of magnetic fields are replaced with plastic-based materials to reduce weight and volume, so that the defect (2) is detected while moving stably in the inclined cable (1). can do.

Referring to FIG. 7 , the first magnetizing yoke 110 , the second magnetizing yoke 120 and the permanent magnet 140 according to an embodiment of the present invention are integrally formed at equal intervals along the circumferential direction of the cable 1 . It can be arranged radially. For example, the first magnetizing yoke 110 , the second magnetizing yoke 120 , and the permanent magnet 140 as a group consist of six sensing parts inside the housing 150 of the cable defect inspection device 100 . can be accepted. In this case, the six sensing parts may be arranged at equal intervals along the circumferential direction of the cable 1 in a form that surrounds the entire cable 1 . That is, the six sensing parts may be spaced apart at intervals of 60 degrees and may be radially disposed with the cable 1 as the center.

On the other hand, the cable defect inspection apparatus 100 according to an embodiment of the present invention is a coil sensor or a hall sensor (not shown) disposed adjacent along the circumferential direction of the cable 1 in order to detect a local defect of the cable 1 . may further include. For example, referring to FIG. 2 , a coil sensor or a hall sensor (not shown) may be disposed adjacent to the cable 1 in a space between the second magnetizing yoke 120 and the cable 1 . This is to measure the magnetic flux leaking to the surface according to the presence or absence of the defect (2). That is, an additional coil sensor or Hall sensor (not shown) disposed adjacent to the cable 1 may be utilized to detect a surface leakage magnetic field for a small-volume object rather than a large-volume object such as the bridge cable 1 can

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

1: Wire rope or cable 2: Defect
100: cable defect inspection device
110: first magnetization yoke 111: first yoke bar
112: coil sensor 120: second magnetization yoke
121: second yoke bar 122: Hall sensor
123: air gap 124: electromagnetic field shielding layer
130: yoke core 140: permanent magnet
150: housing

Claims (8)

a first magnetizing yoke disposed parallel to the central axis of the cable and including a first yoke bar provided with a coil sensor;
a second magnetizing yoke disposed parallel to the first yoke bar and including a second yoke bar provided with a hall sensor; and
and a permanent magnet connected to a yoke core forming both ends of the first magnetization yoke and the second magnetization yoke and disposed adjacent to the cable,
A gap is provided in the second yoke bar to prevent saturation of the Hall sensor, and the Hall sensor is disposed inside the gap,
The second yoke bar is cable defect inspection apparatus, characterized in that formed to have a thinner thickness than the first yoke bar.
delete The method of claim 1,
The air gap is formed in a shape of opening an upper part of the second yoke bar so that the Hall sensor is exposed to the outside, or is formed inside the second yoke bar so that the Hall sensor is not exposed to the outside Cable defect inspection device.
The method of claim 1,
The width of the gap is determined by considering at least one of the thickness of the second yoke bar and the type of the Hall sensor.
delete 5. The method of any one of claims 1, 3 and 4,
Cable defect inspection apparatus, characterized in that the defect characteristic of the cable is estimated based on the voltage corresponding to the amount of time change of the magnetic flux density measured by the coil sensor and the magnetic flux density measured by the Hall sensor.
5. The method of any one of claims 1, 3 and 4,
The first magnetizing yoke, the second magnetizing yoke and the permanent magnet are integrally arranged in a radial direction at equal intervals along the circumferential direction of the cable.
5. The method of any one of claims 1, 3 and 4,
Cable defect inspection apparatus, characterized in that it further comprises a coil sensor or a hall sensor disposed adjacent in the circumferential direction of the cable in order to detect the local defect of the cable.

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