Wire rope flaw detector and wire rope diagnostic method

Abstract

To provide a wire rope flaw detection device and diagnostic method which can reduce a strand noise signal of a wire rope regardless of the arrangement of a magnetic sensor in the long direction (longitudinal direction) of the wire rope.SOLUTION: A wire rope flaw detection device 1 according to the present invention comprises: a magnetizer 30 which forms a magnetic path in a prescribed section of a wire rope; a plurality of magnetic sensors 3 which can detect a magnetic signal derived from a magnetic leakage flux generated from an element wire of the wire rope; and a signal analysis unit 7 which includes a signal collector 17 that collects the magnetic signal output from the magnetic sensor 3 and a signal processor 18 that performs addition processing of the magnetic signal output from the signal collector 17. The signal analysis unit 7 executes phase adjustment of the plurality of magnetic signals detected by the plurality of magnetic sensors 3, acquires addition data of the plurality of magnetic signals applied with the phase adjustment and detects the damage of the wire rope 2 on the basis of the addition data.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a flaw detector for measuring the state of a magnetic metal material, and more particularly to a wire rope flaw detector and a wire rope diagnosis method suitable for use in detecting breaks in wires of a wire rope. [Background technology]

[0002] Patent Document 1 describes a magnetic flaw detector that detects damage to a wire rope by exciting a wire rope moving in the longitudinal direction to a magnetically saturated state and detecting leakage magnetic flux with magnetic sensors arranged around the wire rope. Two rows of magnetic sensors are arranged in the longitudinal direction of the wire rope, with the same number of magnetic sensors in each row being arranged at equal intervals in the circumferential direction. Furthermore, the corresponding magnetic sensors in each row are arranged so that at the moment when one magnetic sensor faces the crest of the wire rope, the other magnetic sensor faces the valley of the wire rope (see abstract). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-156419 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, the strand pitch length of a wire rope used in an elevator changes as it stretches due to the weight of the car during operation. The strand pitch length also changes depending on the length of actual operation. In other words, the strand pitch length changes over time. With wire ropes whose strand pitch length changes over time, it is not possible to position sensors precisely at the peaks and valleys of the strands, and the phase difference between the strand noise signals generated by the peaks and valleys of the strands is not necessarily 90 degrees. Therefore, even if the strand noise signal is added, it does not become an approximately constant value, making it difficult to reduce strand noise.

[0005] An object of the present invention is to provide a wire rope flaw detector and diagnostic method that can reduce strand noise signals in a wire rope regardless of the arrangement of magnetic sensors in the longitudinal direction of the wire rope. [Means for solving the problem]

[0006] In order to achieve the above object, the wire rope flaw detector of the present invention comprises: A wire rope flaw detector for detecting damage to a wire rope, comprising: a magnetizer that forms a magnetic path in a predetermined section of the wire rope; and a plurality of magnetic sensors that can detect magnetic signals derived from leakage magnetic flux generated from wires of the wire rope. a signal analysis unit including a signal collector that collects magnetic signals output from the magnetic sensors and a signal processor that performs addition processing of the magnetic signals output from the signal collector; The signal analysis unit a plurality of magnetic signals detected by the plurality of magnetic sensors; Adjust the position of the peaks and valleys of the waveforms originating from the strands contained in Perform phase adjustment, Acquire sum data of the plurality of phase-adjusted magnetic signals, comparing the summed data with a first threshold value; If the added data is greater than the first threshold value, it is determined that there is damage to the wire rope; When it is determined that the wire rope is damaged, the individual magnetic signals of the plurality of magnetic sensors are compared with a second threshold value, and a first magnetic sensor that detects an individual magnetic signal that is greater than the second threshold value is identified. do.

[0007] In order to achieve the above object, the wire rope diagnosis method of the present invention comprises the steps of: A wire rope diagnosis method using a wire rope flaw detector that detects damage to the wire rope, the method comprising: a magnetizer that forms a magnetic path in a predetermined section of the wire rope; and a plurality of magnetic sensors that can detect magnetic signals derived from leakage magnetic flux generated from wires of the wire rope, a plurality of magnetic signals detected by the plurality of magnetic sensors; Adjust the position of the peaks and valleys of the waveforms originating from the strands contained in performing a phase adjustment; acquiring sum data of the plurality of phase-adjusted magnetic signals; comparing the summed data with a first threshold; If the added data is greater than the first threshold value, it is determined that the wire rope is damaged.and When it is determined that there is damage to the wire rope, comparing the individual magnetic signals of the plurality of magnetic sensors with a second threshold value, and identifying a first magnetic sensor that detects an individual magnetic signal that is greater than the second threshold value; Includes. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a wire rope flaw detector and a diagnostic method that can reduce strand noise signals in a wire rope regardless of the arrangement of magnetic sensors in the lengthwise direction (longitudinal direction) of the wire rope. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram (cross-sectional view) showing the configuration of a sensor unit of a wire rope flaw detector according to an embodiment of the present invention. [Figure 2] 2 is a functional block diagram showing the configuration of a signal processing unit and the like of a wire rope flaw detector according to one embodiment of the present invention, which is configured by connecting the sensor unit of FIG. 1. FIG. [Figure 3] FIG. 4 is a schematic diagram of phase adjustment of a strand noise signal according to an embodiment of the present invention. [Figure 4] 10 is a flowchart of an addition determination process according to an embodiment of the present invention. [Figure 5] 4 is a flowchart of a wire breakage detection process according to an embodiment of the present invention. [Figure 6] FIG. 4 is a diagram showing an example of a detection signal resulting from a break in a wire according to an embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing an example of a display of a determination result according to an embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing the positional relationship between a sensor unit and a wire rope according to a comparative example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] A wire rope is a strand formed by twisting multiple thin wires together, and then twisting the strands around a core rope to form a single bundle. Wire ropes made by twisting together magnetic metal wires are used as hoisting ropes for elevator car cages. Elevator wire ropes, which are used as running ropes, undergo deterioration over time, such as bending fatigue, wear, and corrosion, and therefore require regular inspections and checks. Visual inspection is effective for detecting deterioration that shows obvious changes in appearance, such as rust and corrosion, but there is variation in inspection accuracy among inspectors, and it is difficult to detect abnormalities that occur inside the wire rope.

[0011] Therefore, an effective wire rope safety monitoring technique is to use magnetic leakage flux testing, which detects the deterioration state of wire ropes based on the leakage magnetic flux generated from the wire rope. Magnetic leakage flux testing is a method in which a wire rope is excited and the resulting leakage magnetic flux is detected using a magnetic sensor. A measuring device based on magnetic leakage flux testing (hereinafter referred to as a magnetic leakage flux testing device) is equipped with a magnetizer to magnetize the wire rope, and magnets are attached to both ends of the magnetizer in a direction that reverses the polarity. When the wire rope adheres to the magnetizer, the magnetic field emitted from the magnet causes magnetic flux to flow back between the wire rope and the magnetizer, forming a magnetic path.

[0012] When a wire rope with a magnetic path is damaged, such as by a broken wire, the flow of magnetic flux is interrupted, causing magnetic flux to leak from the wire rope's surface. This leakage magnetic flux can be detected by a magnetic sensor to detect a broken wire. In this case, the magnetic sensor detects not only the signal from the broken wire, but also the periodic signal from the wire rope strands. This is because, unlike pipes with a uniform surface, wire ropes have an uneven surface due to their twisted strands, which constantly generates changes in magnetic flux. The peaks (peaks) of the strands are close to the magnetic sensor, generating a large signal, while the valleys (valleys) of the strands are farther from the sensor, causing the signal to attenuate, resulting in a periodic signal that reflects the strand structure. This is called strand noise or strand noise signal, and is one of the causes of a low S / N ratio when detecting broken wires in wire ropes.

[0013] An example of a leakage flux flaw detector that reduces such strand noise is the leakage flux flaw detector shown in FIG. 8. FIG. 8 is a diagram showing the positional relationship between sensor units 4a and 4b and a wire rope 1 according to a comparative example to the present invention. FIG. 8 is a diagram of a magnetic flaw detector for wire ropes described in Patent Document 1, and the magnetic flaw detector of Patent Document 1 is a type of leakage flux flaw detector. The magnetic flaw detector disclosed in Patent Document 1 excites a wire rope that moves in the longitudinal direction and detects leakage magnetic flux generated from the wire rope using multiple magnetic sensors arranged circumferentially around the wire rope.

[0014] In the magnetic flaw detector shown in Fig. 8, when the wire rope 1 is moved in the longitudinal direction, the magnetic sensors 4a and 4b detect signals from the valleys 1b and crests 1a of the strand, respectively, and these signals are out of phase with each other by 90 degrees. Therefore, by adding the signals from the magnetic sensors derived from the valleys 1b and crests 1a of the strand, it is possible to reduce strand noise.

[0015] Furthermore, Patent Document 1 discloses a technique for calculating the effective cross-sectional area of ​​a wire rope from the total sum of values ​​from multiple magnetic sensors. Since the amount of leakage magnetic flux calculated from the sum is inversely proportional to the effective cross-sectional area, an increase in the amount of leakage magnetic flux indicates damage to the wire rope. Therefore, the external or internal damage state of the wire rope can be determined from changes in the amount of leakage magnetic flux.

[0016] In the magnetic flaw detector of Patent Document 1, magnetic sensors are positioned in advance to align with the peaks and valleys of the wire rope strands. Addition is performed by adjusting the wire rope strand pitch and the number of sensors. However, the wire rope used in elevators stretches due to the weight of the car during actual operation, causing the strand pitch length to change. Therefore, it is not possible to precisely position magnetic sensors at the peaks and valleys of the strands, and the phase difference between the strand noise signals is not necessarily 90 degrees. Therefore, even if the strand noise signal is added, it does not become a nearly constant value, making it difficult to reduce the noise.

[0017] In addition, in Patent Document 1, the total leakage magnetic flux per effective cross-sectional area of ​​the wire rope is calculated from the sum of the magnetic sensor values, but in wire ropes in actual operation, the overall leakage magnetic flux varies greatly due to changes in strand pitch length, making it difficult to accurately determine whether or not there is a break in the internal wire, where the rate of change is particularly small.

[0018] Furthermore, in Patent Document 1, the data from multiple magnetic sensors are added together, and information from each individual magnetic sensor cannot be obtained, so the number of broken wires cannot be identified.

[0019] The magnetic leakage flux flaw detector of this embodiment described below can reduce wire rope strand noise regardless of the arrangement of the magnetic sensor, and can detect the frequency and type of wire breakage. In this embodiment, the magnetic leakage flux flaw detector will be referred to as a wire rope flaw detector.

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram (cross-sectional view) showing the configuration of a sensor unit of a wire rope flaw detector according to one embodiment of the present invention.

[0021] The wire rope 2 shown in Fig. 1 has eight strands 23, and the entire wire rope including these eight strands 23 is twisted together. A wire rope 2 having such a composition is merely one example of a target to be inspected by the wire rope flaw detector 1 of this embodiment, and wire ropes having a different number of strands can also be diagnosed by the wire rope flaw detector 1 of this embodiment.

[0022] The wire rope 2 and strands 23 are further composed of numerous wires 24, and the wire rope flaw detector 1 is required to reliably detect any breaks in the wires 24. Breaks in the wires vary depending on the location; if they occur on the outer periphery of the strand 23, they are called mountain breaks 25 in the wire, and if they occur midway between adjacent strands, they are called valley breaks 26 in the wire. In other words, a valley break 26 is a break in a wire midway between the outermost and innermost parts of the strand 23 in the circumferential direction of the strand 23.

[0023] The magnetizer 30 forms a magnetic path in a predetermined section in the longitudinal direction of the wire rope 2. The magnetic sensor 3 is installed along the outer periphery of the cross section of the protective cover 22 of the wire rope 2. A plurality of magnetic sensors 3 are arranged at equal intervals along the outer periphery of the wire rope 2 and, together with the protective cover 22, form an annular sensor unit 20. The wire rope 2 is inspected by inserting it into the ring of the annular sensor unit 20, but since it is extremely difficult to insert the wire rope 2 in an elevator that is in operation, in actual inspection, the annular or cylindrical sensor unit 20 is split in two circumferentially, the wire rope 2 is clamped inside the open section, and the loop is then closed back together before inspection.

[0024] 1, typical types of magnetic sensors 3 include detection coils and Hall elements, but other types such as TMR (Tunnel Magneto Resistive) sensors, AMR (Anisotropic Magneto Resistive) sensors, and GMR (Giant Magneto Resistive effect) sensors can also be used. The arrangement of the magnetic sensors 3 constituting the sensor unit 20 is determined based on the type of magnetic sensor 3.

[0025] This arrangement is preferably such that multiple magnetic sensors 3 are installed at a predetermined interval (pitch) around the outer periphery of the wire rope 2 in order to efficiently detect breaks in the wires 24 using a minimum number of magnetic sensors 3. The magnetic sensors 3 that make up the sensor unit 20 are installed at equal intervals in a single row around the outer periphery of the wire rope 2, forming an annular sensor group. Two or more rows of annular sensor groups each made up of multiple magnetic sensors 3 may be arranged, and the multiple annular sensor groups may be arranged with a shift in the axial direction (longitudinal direction of the wire rope). In this case, the multiple annular sensor groups may be adjacent to each other on the same axis. The more magnetic sensors 3 that make up the sensor unit 20, the denser and more accurate they are to cover all breaks in the wires 24, but the sensor unit 20 is designed efficiently to include the minimum number of magnetic sensors 3 required.

[0026] FIG. 2 is a functional block diagram showing the configuration of a signal processing unit and the like of a wire rope flaw detector 1 according to an embodiment of the present invention, which is configured by connecting the sensor unit 20 of FIG. As shown in Fig. 2, the wire rope flaw detector 1 is configured with a sensor unit 20, a magnetic sensor circuit (magnetic sensor circuit unit) 5, a signal analysis unit 7, a data display unit 8, and a data input unit 9. The data input unit 9 and the data display unit 8 have a general-purpose computer (hereinafter referred to as "PC 18") connected to a power supply 10 and a control circuit 11, which is operated by a user to control the wire rope flaw detector 1. The control circuit 11 controls the magnetic sensor circuit 5 and the signal analysis unit 7.

[0027] FIG. 2 shows only two representative paths (channels, hereinafter also referred to as "ch") corresponding to two magnetic sensors 3. However, the actual number of magnetic sensors 3 constituting the sensor unit 20 is basically the same as the number of strands 23 (eight in this embodiment) or an integer multiple (ch). This is to detect peaks and valleys (strand noise) originating from the strands 23 and cancel the strand noise using a processing procedure described below. Specifically, when there are eight strands 23, the magnetic sensor 3 is provided with 8, 16, or 24 channels; FIG. 1 illustrates the case of 16 channels. The magnetic signal detected by the magnetic sensor 3 is amplified and noise is removed by the magnetic sensor circuit 5, and the signal is output to the signal analysis unit 7.

[0028] The magnetic sensor circuit 5 has a magnetic signal amplifier (magnetic signal amplifier section) 12 and a filter circuit (filter circuit section) 13. The magnetic signal amplifier 12 amplifies the output signal from the magnetic sensor 3. The filter circuit 13 performs general analog filtering on the output signal amplified by the magnetic signal amplifier 12, and outputs an analog signal. The analog filtering removes noise components including commercial frequency noise, and passes signals only in the desired frequency range.

[0029] In this way, the magnetic sensor circuit 5 performs analog processing on the magnetic detection signal output from the magnetic sensor 3, and outputs the analog magnetic signal to the signal analysis unit 7. The signal analysis unit 7 is composed of an A / D converter (A / D conversion unit) 16, a signal collector (signal collection unit) 17, and a signal processor (signal processing) 18. The A / D converter 16 converts the analog magnetic signal output from the magnetic sensor circuit 5 into a digital signal, and outputs it to the signal collector 17. The signal processor 18 includes a one-chip microcomputer, a single-board computer, or the like.

[0030] The signal processor 18 stores the digital magnetic signal output from the A / D converter 16 in the signal collector 17 by having the CPU (Central Processing Unit) read and execute a program stored in memory or storage. The signal processor 18 also has the functions of signal addition and digital filtering, and processes the signal after A / D conversion. It also holds threshold values ​​that serve as judgment criteria predefined for each type of wire rope.

[0031] The processing by the signal analysis unit 7 can be realized by program processing in the signal processor 18, and the data display unit 8 and data input unit 9 can also be associated devices of the signal processor 18 such as a keyboard and a liquid crystal display.

[0032] Next, an overview of the analysis process for determining whether a wire in a wire rope has been broken in the signal analysis unit 7 of the wire rope flaw detector 1 will be given, and then the processing procedure will be described in detail with reference to the drawings.

[0033] The leakage magnetic flux of the wire rope 2 is detected by the magnetic sensor 3 and, as mentioned above, is converted into a digital signal by the A / D converter 16 of the signal analysis unit 7. If damage occurs to the wire rope 2, the leakage magnetic flux signal resulting from a broken wire is also converted into a digital signal. Strand noise generated from the strands 23 of the wire rope 2 and electromagnetic noise mixed in from outside are also converted in addition. Therefore, the signal processor 18 can use a digital filter to reduce the main noise, but because the strand noise has a frequency very close to the signal frequency of a broken wire, it is difficult to remove using only a digital filter.

[0034] Therefore, in order to reduce the strand noise, the phase of the signal is adjusted and added. Figure 3 is a schematic diagram of the phase adjustment of the strand noise signal according to one embodiment of the present invention.

[0035] The upper and lower signals in Figure 3(A) are outputs from different magnetic sensors, and are signals before the phase of the strand waveform has been adjusted. If these signals were added as is, the peaks and valleys of the signals would not cancel each other out, resulting in increased strand noise. Therefore, by detecting the peaks of the waveform and adjusting the phase from the reference signal as shown in Figure 3(B), the peaks and valleys of the signal can be canceled out, and the signal after addition will have reduced strand noise, as shown in Figure 3(C). In this embodiment, the signal in the upper row is used as the reference signal, and the phase of the signal in the lower row is adjusted.

[0036] Furthermore, by adding up the signals from the magnetic sensors 3 in the circumferential direction of the rope in the signal analysis unit 7, it is possible to capture changes in the leakage magnetic flux in the cross section of the wire rope. In this embodiment, among the determination processes by the signal analysis unit 7, the process for adding up the leakage magnetic flux is called the "addition determination process," and the process flow is shown in Figure 4, which will be described later.

[0037] 4 is a flowchart of the addition determination process according to one embodiment of the present invention, assuming that the magnetic sensor 3 has 16 channels.

[0038] 4, first, measurement of magnetic signals by the magnetic sensors 3 is started under the control of the control circuit 11 (step S11). The magnetic sensors 3 are attached to a wire rope, and as the wire rope moves in the longitudinal direction, magnetic signals can be acquired as time-series data of leakage magnetic flux. The magnetic signals output from the magnetic sensors 3 of each channel detected in step S11 are subjected to analog processing by the magnetic sensor circuit 5, converted to digital signals by the A / D converter 16 of the signal analysis unit 7, and then stored in the signal collector 17.

[0039] Next, the signal processor 18 performs phase adjustment of the strand noise signal for the digital magnetic signal of each channel stored in the signal collector 17 (step S12). As a result of the phase adjustment of the magnetic signal in step S12, the positions of the peaks and valleys of the strand noise signal waveform are adjusted, and a time series total value (added data) is obtained by an addition process in step S13.

[0040] Next, the signal processor 18 compares the entire time-series sum of the magnetic signal calculated in step S13 with a previously stored reference value (threshold, first threshold) and determines whether or not an abnormality exists by comparing the values ​​(step S14). In step S14, if the time-series sum is equal to or lower than the threshold, the wire rope is determined to be normal (step S15). If the time-series sum exceeds the threshold (NO in step S14), the signal processor 18 diagnoses that an abnormality has occurred in the measured length of the wire rope and displays the analysis result on the data display unit 8 (step S16), and proceeds to step S17 for detailed determination of the abnormality.

[0041] As described above, the wire rope flaw detector 1 of this embodiment has the following features: A wire rope flaw detector (1) for detecting damage to the wire rope (2) includes a magnetizer (30) that forms a magnetic path in a predetermined section of the wire rope (2) and a plurality of magnetic sensors (3) that can detect magnetic signals derived from leakage magnetic flux generated from the wires of the wire rope (2), a signal analysis unit (7) including a signal collector (17) that collects magnetic signals output from the magnetic sensor (3) and a signal processor (18) that performs addition processing of the magnetic signals output from the signal collector (17); The signal analysis unit 7 performs phase adjustment of multiple magnetic signals detected by multiple magnetic sensors 3, obtains additive data of the phase-adjusted multiple magnetic signals, and detects damage to the wire rope 2 based on the additive data.

[0042] The phase adjustment of the plurality of magnetic signals adjusts the positions of the peaks and valleys of the waveforms originating from the strands contained in the plurality of magnetic signals.

[0043] The signal analysis unit 7 then compares the added data with a first threshold value, and determines that the wire rope 2 is damaged (wire breakage) if the added data is greater than the first threshold value.

[0044] In addition, the diagnostic method for the wire rope 2 of this embodiment is as follows: A wire rope diagnosis method using a wire rope flaw detector that includes a magnetizer that forms a magnetic path in a predetermined section of the wire rope and a plurality of magnetic sensors that can detect magnetic signals derived from leakage magnetic flux generated from the wires of the wire rope, and detects damage to the wire rope, comprising: Step S12: performing phase adjustment of a plurality of magnetic signals detected by a plurality of magnetic sensors 3; Step S13: acquiring sum data of the phase-adjusted magnetic signals; Step S14 detects damage to the wire rope 2 based on the added data; Includes.

[0045] The processing flow shown in Figure 4 is a processing flow for determining whether or not an abnormality (wire breakage) has occurred over the entire length of the wire rope 2 and its frequency based on the threshold value (first threshold value) stored in the signal processor 18, and the processing flow of Figure 5 described below is a processing flow for determining the type of wire breakage.

[0046] 5 is a flowchart of a wire breakage detection process according to one embodiment of the present invention. In the example of the processing procedure in FIG. 5, a further detailed analysis is performed on a wire rope that has been found to be abnormal by the addition detection process. This further detailed analysis is called "wire breakage detection."

[0047] In determining whether a wire has been broken, the individual signals (wire determination data) of each channel stored in the signal collector 17 are acquired (step S21). Next, the signal processor 18 compares the numerical values ​​of the individual signals of each channel with a threshold value (second threshold value) stored in advance (step S22), and determines that there is no abnormality in any channel if the numerical value is equal to or less than the threshold value (step S23).

[0048] The signal from the magnetic sensor 3 of a channel that exceeds the threshold is determined to be abnormal (there is a wire break) (step S24), and the signals from adjacent channels are compared (step S25). This is because the spread of leakage magnetic flux varies depending on the type of wire break, and an internal break, such as a valley break (reference numeral 26 in FIG. 1), spreads the magnetic field distribution due to the distance from the magnetic sensor 3, and is detected by the magnetic sensors 3 of multiple channels. Therefore, a judgment is made based on a threshold (third threshold) for adjacent channels, and if a channel with a value above the threshold is detected, the wire is determined to have a valley break (step S26). On the other hand, if the signal from the magnetic sensor 3 of the adjacent channel is smaller than the third threshold, the magnetic flux leakage to the multiple magnetic sensors 3 is small and the distribution is steep, so the wire is determined to have a mountain break (reference numeral 25 in FIG. 1) (step S27).

[0049] In the determination of the first threshold, the second threshold, and the third threshold described above, it is possible to appropriately select whether or not to include the value of each threshold.

[0050] As described above, in this embodiment, when it is determined that the wire rope 2 is damaged, the signal analysis unit 7 compares the individual magnetic signals of the multiple magnetic sensors 3 with the second threshold value, and identifies the magnetic sensor (first magnetic sensor) 3 that detected an individual magnetic signal that is larger than the second threshold value.

[0051] Furthermore, the individual magnetic signal of the second magnetic sensor 3 adjacent to the first magnetic sensor 3 is compared with a third threshold value, and if the magnetic signal of the second magnetic sensor 3 is larger than the third threshold value, it is determined that a valley break 26 has occurred in the wire of the wire rope 2, and if the magnetic signal of the second magnetic sensor 3 is larger than the third threshold value, it is determined that a mountain break has occurred in the wire of the wire rope 2.

[0052] In other words, when the magnetic signals from the adjacent magnetic sensors 3 are greater than a predetermined value (the second threshold or the third threshold), it is determined that a valley break has occurred in the wire of the wire rope 2.

[0053] In this case, if the magnetic signal of one magnetic sensor (first magnetic sensor) 3 among the plurality of magnetic sensors 3 is greater than the second threshold value, it is determined that a break has occurred in the wire of the wire rope 2.

[0054] Then, when the magnetic signal of the magnetic sensor (second magnetic sensor) adjacent to one magnetic sensor (first magnetic sensor) 3 is greater than the third threshold value, it is determined that a valley break in a wire of the wire rope 2 has occurred.

[0055] FIG. 6 shows an example of a detection signal resulting from a wire breakage according to one embodiment of the present invention. FIG. 6(A) shows the summed waveform of 16 channels of magnetic sensors 3, and a signal range 70 exceeding the threshold is detected along part of the entire length of the rope. FIG. 6(B) shows a channel in which an abnormality was detected in step S24 of FIG. 5, allowing detailed observation of the wire breakage. In FIG. 6, the vertical axis represents the amplitude of the signal detected by the magnetic sensors 3, and the horizontal axis represents the movement time of the sensor unit 20 relative to the wire rope 2. The movement time on the horizontal axis corresponds to the position in the longitudinal direction of the wire rope 2. Note that FIG. 6(B) shows an example in which four wire breakages (four locations) have been detected.

[0056] The results of such determination are displayed on the data display unit 8. The data display unit 8 is, for example, a liquid crystal display connected via an output interface, and displays the results of processing executed by the signal analysis unit 7 (analysis result display screen).

[0057] Fig. 7 is a diagram showing an example of the display of the judgment results according to one embodiment of the present invention. Fig. 7 shows a specific example of an analysis result display screen by the data display unit 8. The analysis result display screen displays, for example, the presence or absence of an abnormality in the summation judgment, the type of wire break (valley break or mountain break), the number of broken wires, the model number, the analysis date and time, etc., together with the wire rope data (summation data and wire judgment data).

[0058] As described above, the wire rope flaw detector 1 of this embodiment can reduce the strand noise of the wire rope and detect leakage magnetic flux generated from a wire break in the wire rope 2, regardless of the placement of the magnetic sensor 3, and can also perform simple abnormality detection and detailed wire break detection by adding signals. [Industrial Applicability]

[0059] The present invention may be employed as a wire rope flaw detector and a wire rope diagnostic method for inspecting hoisting cables in the safety monitoring of elevators. [Explanation of symbols]

[0060] 1...wire rope flaw detector, 2...wire rope, 3...magnetic sensor, 5...magnetic sensor circuit, 7...signal analysis unit, 8...data display unit, 9...data input unit, 17...signal collector, 18...signal processor, 20...sensor unit, 23...strand, 24...wire, 25...break (mountain break) in wire 24 in wire rope 2, 26...break (valley break) in wire 24 in wire rope 2.

Claims

1. A wire rope flaw detector for detecting damage to a wire rope, comprising: a magnetizer that forms a magnetic path in a predetermined section of the wire rope; and a plurality of magnetic sensors that can detect magnetic signals derived from leakage magnetic flux generated from wires of the wire rope. a signal analysis unit including a signal collector that collects magnetic signals output from the magnetic sensors and a signal processor that performs addition processing of the magnetic signals output from the signal collectors; The signal analysis unit performing phase adjustment to adjust the positions of peaks and valleys of waveforms originating from the strands included in the plurality of magnetic signals detected by the plurality of magnetic sensors; acquiring summed data of the plurality of phase-adjusted magnetic signals, and comparing the summed data with a first threshold value; If the summed data is greater than the first threshold value, it is determined that there is damage to the wire rope; A wire rope flaw detection device characterized by comparing the individual magnetic signals of the multiple magnetic sensors with a second threshold value when it is determined that there is damage to the wire rope, and identifying the first magnetic sensor that detected an individual magnetic signal that is larger than the second threshold value.

2. In claim 1, comparing an individual magnetic signal of a second magnetic sensor adjacent to the first magnetic sensor with a third threshold; When the magnetic signal of the second magnetic sensor is greater than the third threshold value, it is determined that a valley break has occurred in a wire of the wire rope; A wire rope flaw detector characterized in that it determines that a wire break has occurred in the wire rope when the magnetic signal of the second magnetic sensor is smaller than the third threshold value.

3. In claim 1, A wire rope flaw detector characterized by determining that a wire break has occurred in the wire rope when the magnetic signal of one of the plurality of magnetic sensors is greater than a second threshold value.

4. In claim 3, A wire rope flaw detector characterized by determining that a valley break has occurred in a wire of the wire rope when the magnetic signal of a magnetic sensor adjacent to the one magnetic sensor is larger than a third threshold value.

5. In claim 1, A wire rope flaw detector that determines that a valley break has occurred in a wire of the wire rope when the magnetic signals of multiple adjacent magnetic sensors are larger than a predetermined value.

6. A wire rope diagnosis method using a wire rope flaw detector that detects damage to the wire rope, the method comprising: a magnetizer that forms a magnetic path in a predetermined section of the wire rope; and a plurality of magnetic sensors that can detect magnetic signals derived from leakage magnetic flux generated from wires of the wire rope, performing a phase adjustment to adjust the positions of peaks and valleys of waveforms originating from the strands included in the plurality of magnetic signals detected by the plurality of magnetic sensors; acquiring sum data of the plurality of phase-adjusted magnetic signals; comparing the summed data with a first threshold; determining that the wire rope is damaged when the summed data is greater than the first threshold value; When it is determined that there is damage to the wire rope, comparing the individual magnetic signals of the plurality of magnetic sensors with a second threshold value, and identifying a first magnetic sensor that detected an individual magnetic signal that is greater than the second threshold value; A wire rope diagnostic method comprising:

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