Wire rope diagnostic device

Abstract

The purpose of the present invention is to provide a structure enabling strong, uniform magnetization of the entire cross-section of a wire rope, present a flexible structure so that sensors can be precisely arranged according to the magnetic flux distribution, and provide a wire rope diagnostic device that achieves both optimization of magnetic flux density distribution and precision of sensor arrangement, and thus can detect even minute defects with high sensitivity. According to the present invention, the wire rope diagnostic device comprises: one or more magnetic structures arranged along the outer circumference of a wire rope; and a flexible substrate on which are installed a plurality of magnetic flux detection sensors, which are Hall sensors or magnetoresistive (MR) sensors, arranged at or near the center of the magnetic structures, wherein the flexible substrate is made of one selected from among polyimide, PET, and an insulating material.

Description

Wire rope diagnostic device

[0001] The present invention relates to a device for diagnosing damage to a wire rope using magnets and sensors.

[0002] Wire ropes are steel structures widely used to support loads or lift objects in heavy equipment, cranes, elevators, port facilities, and more. A wire rope is composed of tens to hundreds of twisted metal strands, and prolonged use leads to the accumulation of damage such as fatigue, wear, corrosion, and wire breakage, posing a risk of fracture. Accordingly, the development of diagnostic technologies capable of preventing safety accidents by detecting internal and external defects in wire ropes at an early stage is essential.

[0003] Wire ropes are used as critical tension members in heavy lifting systems for elevators, cranes, construction equipment, and ships. During use, these wire ropes may develop defects such as fatigue accumulation, wear, and breakage, and accidents resulting from these issues can cause casualties and massive property damage. Accordingly, active technological development is underway for devices that detect wire rope defects in real-time using a non-contact method.

[0004] Wire rope damage diagnosis technology is based on the principles of Non-Destructive Testing (NDT). When divided into diagnosis principles and methods, the highly reliable Magnetic Flux Leakage (MFL) method is used, which uses a magnet to induce (magnetize) magnetic flux in the wire rope and measures the magnetic flux leakage, a phenomenon where magnetic flux leaks at a defective area, using a Hall sensor or MR sensor to detect internal defects; the Magnetic Saturation method, which magnetizes the entire rope with a strong magnetic flux and detects the phenomenon where the magnetic flux is distorted at a defective area while the flux is maintained at a constant level; the Inductive / Eddy Current method, which applies an alternating magnetic field to the wire rope to measure changes in eddy currents generated at the damaged area of ​​the metal; and the Ultrasonic or Acoustic Emission method, which detects internal defects by utilizing the reflection or attenuation of waves generated within the metal.

[0005] The technical application according to the present invention is utilized for periodic inspection of elevator ropes, port crane wire inspection, mining cable car / winch system inspection, and construction site tower crane rope inspection.

[0006] The diagnostic device of the present invention mainly uses a method of applying magnetic flux to a wire rope using a magnet and a sensor and detecting changes in magnetic flux when a defect occurs, and some devices have problems with poor uniformity of magnetic flux distribution because the sensor is placed on a fixed metal substrate or the magnetic structure is fragmentary.

[0007] The present invention aims to provide a wire rope diagnostic device capable of detecting even minute defects with high sensitivity by simultaneously satisfying the optimization of magnetic flux density distribution and the precision of the sensor array, by providing a structure that enables uniform and strong magnetization across the entire cross-section of the wire rope and a flexible structure that allows for the precise placement of sensors according to the magnetic flux distribution.

[0008] The problems solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0009] As a means to solve the aforementioned technical problem, according to an embodiment of the present invention, one or more magnetic structures arranged along the outer circumference of a wire rope; and a flexible substrate on which a plurality of magnetic flux sensing sensors, among a Hall sensor or a magnetoresistance sensor (MR sensor), are installed at the center or near the magnetic structure, wherein the flexible substrate is composed of one selected from polyimide, PET, or an insulating material.

[0010] The above magnet structure is characterized in that the upper magnet and the lower magnet are each formed in a semicircular shape and arranged to surround the outer circumference of the wire rope in the vertical direction, and the magnetic flux is induced in the direction of the sensor, and the magnet structure is composed of a divided structure that forms a local magnetic flux at a 90-degree angle to the outer circumference of the wire rope.

[0011] The plurality of magnetic flux sensing sensors are arranged at equal intervals on the flexible substrate and are arranged in a direction traversing the cross-section of the wire rope.

[0012] The above-described magnetic structure and a housing that accommodates a flexible substrate are further included, wherein the housing is made of a material selected from aluminum, engineering plastic, or a non-magnetic material.

[0013] The magnetic flux sensing sensors are arranged in a structure that is arranged in an arc shape along the radial direction from the center of the wire rope toward the outer edge or along the circumferential direction of the wire rope, and the flexible substrate is formed in a single-layer structure in which the magnetic flux sensing sensors are fixedly arranged or in a multi-layer structure in which a plurality of sensors wired independently of each other are stacked.

[0014] The above magnetic flux sensing sensor is characterized by prioritizing the placement of the sensor at the location where the rate of change of magnetic flux density is maximum, based on a magnetic flux distribution simulation.

[0015] According to the present invention, the wire rope diagnostic device has a uniform and strong magnetic flux distribution, which can induce even magnetization across the entire cross-section of the wire rope. Additionally, by placing the sensor on a flexible PCB, a structurally free sensor arrangement is possible, making it suitable for curved structures. Furthermore, since the magnetic structure is continuous, it has the effect of reducing noise or sensitivity deviation during measurement. Moreover, it offers great design flexibility during manufacturing and enables miniaturization and modularization, making it applicable to various diagnostic devices.

[0016] FIG. 1 is a cross-sectional view of a diagnostic device according to the present invention.

[0017] FIG. 2 is a design drawing of a diagnostic device according to the present invention.

[0018] FIG. 3 is an exemplary embodiment according to the present invention.

[0019] FIG. 4 is an example diagram of a magnetic configuration according to the present invention.

[0020] FIG. 5 is an exemplary diagram of a diagnostic device according to the present invention.

[0021] Further objects, features, and advantages of the present invention can be more clearly understood from the following detailed description and the accompanying drawings.

[0022] Before providing a detailed description of the present invention, it should be understood that the present invention is capable of various modifications and may have various embodiments, and that the examples described below and illustrated in the drawings are not intended to limit the present invention to specific embodiments, but rather include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0023] Hereinafter, specific technical details to be implemented in the present invention will be described in detail with reference to the attached drawings.

[0024] The magnetic (magnet) according to the present invention is made of NdFeB material and has an inner surface that forms a semicircle to form magnetic flux along the outer circumference of the wire rope. The magnetic is placed on the upper and lower sides of the FPCB (Flexible Printed Circuit Board) so that magnetic flux is concentrated in the direction of the sensor from both directions. The flexible PCB is made of a polyimide substrate and is designed to bend radially and is inserted inside the magnetic. The sensor is composed of Hall sensors, for example, 6 to 12 or more are arranged at regular intervals or along the magnetic flux centerline. The entire structure is assembled within a housing made of thermosetting plastic, aluminum, or non-magnetic metal and is fixed to the diagnostic position of the wire rope through fixing screws or slots.

[0025] In a continuous magnet structure, magnetic flux density is uniformly distributed from the center to the edge, whereas in a segmented magnet structure, magnetic flux is concentrated only in specific regions, resulting in large magnetization deviations. Therefore, the structure of the present invention exhibits excellent magnetic flux uniformity and high defect detection accuracy.

[0026] The magnetic structure of the present invention consists of semicircular magnets made of a high magnetic flux density material such as NdFeB, with semicircular magnets positioned on the upper and lower sides, respectively, to allow the wire rope to pass through. The magnets are designed to wrap around the wire rope to concentrate the magnetic flux and to induce the flux toward the center where the sensor is located. This structure enables damage detection across the entire cross-section by inducing uniform magnetization not only at the center but also at the outer edges of the wire rope.

[0027] Sensors for detecting changes in magnetic flux are placed in multiple locations on the FPCB, and the FPCB is based on polyimide material and can be flexibly placed in close contact with the curved surface inside the magnet structure. The sensors consist of Hall Effect Sensors and can detect changes in the absolute value or direction of magnetic flux.

[0028] Sensors are arranged at regular intervals along an arc or along points where the gradient of the magnetic flux density distribution is large. For example, when locating points with a large rate of change of magnetic flux, sensitivity efficiency is maximized by prioritizing the placement of sensors around points where the gradient value is greater than a threshold value. Generally, sections with a large magnetic flux gradient correspond to locations with the best signal-to-noise ratio (SNR) due to the sensor sensitivity characteristics.

[0029] The interval between sensors (I; interval) must be set so that the interval is smaller than the value obtained by dividing the wire rope diameter (D; diameter) by 4 (i.e., I ≤ D / 4). For example, if the wire rope diameter is 20 mm, the sensor interval must be set to at least 5 mm or less to enable detection without missing minute details.

[0030] Alternatively, the spacing between sensors can be determined by calculating the rate of change in magnetic flux density through a magnetic flux distribution simulation that reflects the wire rope diameter, and then placing the sensors at the location where the rate of change is maximum.

[0031] The above magnet and FPCB structure are assembled by being inserted into a housing made of thermosetting plastic or a non-magnetic material (e.g., aluminum or non-magnetic plastic). The housing includes a slit-shaped opening through which a wire rope can pass and screw or clamp holes for securing the device, thereby facilitating field installation. The entire structure ensures durability against external impacts, and guide grooves or protrusions may be provided to allow the FPCB to maintain an accurate position within the magnet structure.

[0032] FIG. 1 is a cross-sectional view of a wire rope diagnostic device. Hall sensors (120) are arranged continuously on a flexible PCB (130), and magnets (110) are arranged on each side of the flexible PCB. A wire rope (140) passing through a circular magnet (110) is magnetized by the magnet, and information collected by the Hall sensors (120) is transmitted via a wired or wireless connection to an external analysis server through a terminal.

[0033] The above-described semicircular magnetic structure includes a series of magnet structures arranged in a semicircle to wrap around the outer circumference of the wire rope, with the magnets positioned on the upper and lower sides, respectively, to form a stable magnetic flux centered on the sensor. This structure maximizes the uniformity of the magnetic flux distribution. In addition to a pair of semicircular magnetic structures, the semicircular magnets may also have a form in which 90-degree semicircular magnets are combined. This is because, depending on the thickness of the wire rope, the semicircular magnets, which are a combination of 90-degree semicircular magnets, may exhibit a more uniform magnetic flux distribution. Furthermore, the yoke may be made of a magnetic material to prevent magnetic flux leakage from the magnet.

[0034] A flexible circuit board (FPCB) can be inserted into a semicircular magnet and positioned along a curved surface, and multiple Hall sensors can be arranged densely or at equal intervals at positions optimized for magnetic flux distribution, and due to the flexible characteristics of the board, the sensor placement can be freely designed to suit the structure.

[0035] FIG. 2 is a configuration diagram of a diagnostic device showing that the magnet is configured in a semicircular shape, and it may be configured with a pair of semicircular magnets, or the semicircular magnets may be configured in a structure where they are divided into two and combined.

[0036] Figure 3 shows one side of an actual product including the structure of a flexible PCB with a sensor attached.

[0037] A continuous semicircular magnet structure is one in which an arc-shaped magnet completely surrounds a wire rope. This structure can generate a uniform and strong magnetic field (B-field), ensuring that magnetic flux is evenly distributed across the entire cross-section of the wire rope. In this case, the entire structure is magnetized evenly, allowing for the detection of even minute internal defects. Due to the uniform distribution of magnetic flux, there is minimal variation in sensitivity depending on the sensor placement. However, while this structure offers high sensor measurement stability due to the constant magnetic flux density (B), there is a possibility of remnant magnetization if the magnetization becomes too strong.

[0038] On the other hand, a segmented magnet structure is a structure in which multiple magnets are arranged at intervals, characterized by magnetic flux concentration only at the locations where the magnets are present and a sharp decrease in magnetic flux density in other areas. Consequently, partial magnetization occurs in the wire rope, and the quality of magnetization may deteriorate due to the non-uniform magnetic flux distribution. Although high-sensitivity detection is possible in the sections where the magnets are present, the non-uniformity of the magnetic field prevents the entire wire rope from being evenly magnetized, leading to noise or sensitivity differences in measurement and potentially causing defects to be missed.

[0039] Through experiments comparing a semicircular magnet structure and a 16-part magnet structure using a neodymium magnet with a magnetic flux density (Br) of 1.2 T, the results showed that the semicircular continuous magnet exhibited a pattern where the magnetic flux density increased uniformly from the center to the edge and had a relatively uniform distribution, whereas the magnet showed a rapid decrease in magnetic flux from the center and formed high magnetic flux only in the region close to the magnet.

[0040] Cross-sectional position Semicircular magnet structure Split magnet structure Center 0.8 40.61 Radius 25% 0.9 20.72 Radius 50% 1.0 30.89 Radius 75% 1.1 40.91 Edge 1.1 70.93

[0041] According to experimental results, in a semicircular magnet structure, the magnetic flux density is uniformly distributed from the center to the edge at 0.84 to 1.17 T, whereas in a segmented magnet structure, the magnetic flux is concentrated only in specific areas, resulting in a large variation in magnetization. Therefore, the semicircular structure according to the present invention exhibits excellent magnetic flux uniformity and high defect detection accuracy. The present invention relates to a device capable of precisely diagnosing damage to a wire rope, comprising a semicircular magnet structure and a Flexible Printed Circuit Board (FPCB), and configured to enable high-precision magnetic flux detection by arranging a plurality of magnetic sensors within the structure. Accordingly, the semicircular magnet structure is advantageous for precise diagnosis and allows for free sensor placement based on a uniform magnetic flux distribution, whereas the segmented magnet structure is suitable for lightweighting and selective detection but may result in a decrease in sensitivity due to magnetic flux non-uniformity.

[0042] FIG. 4 is an example of creating a mockup with a total of four structures by further dividing a semicircular magnet structure, and FIG. 5 is an example of a wire rope diagnostic device according to the present invention.

[0043] In addition, the symbols in the drawing correspond to 110 for magnetic, 120 for Hall sensor, 130 for flexible PCB, 140 for wire rope, 150 for screw (coupling device), 160 for terminal, and 170 for yoke.

Claims

1. A device for diagnosing whether a wire rope is damaged, One or more magnetic structures arranged along the outer circumference of the wire rope; A flexible substrate on which a plurality of magnetic flux sensing sensors are installed among a Hall sensor or a magnetoresistance sensor (MR sensor) disposed at the center or near the center of the above-mentioned magnetic structure; A wire rope diagnostic device characterized in that the flexible substrate is composed of one selected from polyimide, PET, or an insulating material.

2. In Paragraph 1, The above magnet structure is A wire rope diagnostic device characterized by having an upper magnet and a lower magnet each formed in a semicircular shape and arranged to surround the outer circumference of the wire rope in the vertical direction, and magnetic flux being guided in the direction of the sensor.

3. In Paragraph 2, The above magnet structure is A wire rope diagnostic device characterized in that the upper magnet and the lower magnet are each configured with a structure divided at 90 degrees.

4. In Paragraph 1, The above plurality of magnetic flux sensing sensors A wire rope diagnostic device characterized by being arranged at equal intervals on the above-mentioned flexible substrate and arranged in a direction traversing the cross-section of the wire rope.

5. In Paragraph 1, It further includes a housing that accommodates the above-mentioned magnet structure and a flexible substrate, and A wire rope diagnostic device characterized in that the housing is composed of a material selected from aluminum, engineering plastic, or a non-magnetic material.

6. In Paragraph 1, The above magnetic flux detection sensor is A wire rope diagnostic device characterized by being arranged in an arc shape along the radial direction from the center of the wire rope toward the outer edge or along the circumferential direction of the wire rope.

7. In Paragraph 1, A wire rope diagnostic device characterized in that the flexible substrate is formed as a single-layer structure in which magnetic flux sensing sensors are fixedly arranged, or as a multi-layer structure in which a plurality of sensors wired independently of each other are stacked.

8. In Paragraph 1, The above magnetic flux detection sensor is A wire rope diagnostic device characterized by prioritizing the placement of a sensor at the location where the rate of change of magnetic flux density is maximum, based on a magnetic flux distribution simulation.

9. In Paragraph 1, A wire rope diagnostic device further comprising a yoke located on the back side of the flexible substrate, formed along the flexible substrate, and composed of a magnetic material.

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