Wire Rope Inspection System

Abstract

To provide a wire rope inspection system with which, when detecting a change amount of magnetic flux of a wire rope by a pair of dividable detection coils, each forming a coil loop, it is possible to reduce a noise component attributable to the inherent magnetic characteristic of the wire rope having a bearing of the magnetic flux in a direction orthogonal to a direction in which the wire rope extends.SOLUTION: This wire rope inspection system 100 includes a control unit 50 that acquires a difference between a detection signal from a first differential coil 31 and a detection signal from a second differential coil 32. A pair of detection coils 31a and 31b (32a and 32b) in each of the first and second differential coils 31 and 32 respectively form a coil loop and, by being combined with each other, are wound so as to surround the wire rope.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wire rope inspection system. [Background technology]

[0002] BACKGROUND ART Wire rope inspection devices that detect changes in magnetic flux in a wire rope are known (see, for example, Patent Documents 1 and 2).

[0003] The wire rope inspection device described in Patent Document 1 above includes a detector coil that detects changes in the magnetic field of the wire rope. This detector coil is provided in the detector main body. The detector main body, including the detector coil, is configured to be separable so that it can be attached to the wire rope from the short side. Patent Document 1 also discloses an example in which the detector coil is configured as a pair of saddle coils that are placed in each of the divided detector main body parts. Here, wire ropes have inherent magnetic properties that depend on differences in the uniformity of twist and the uniformity of the amount of steel. When measuring with a detector coil, these inherent magnetic properties of the wire rope are output as noise data in comparison to the output when measuring damaged areas.

[0004] Therefore, the wire rope inspection device described in Patent Document 2 acquires a first detection signal using a detector coil in a first measurement before damage occurs to the wire rope. Then, in order to detect damage that has occurred to the wire rope, this wire rope inspection device acquires a second detection signal using a detector coil in a second measurement after the first measurement. Then, the wire rope inspection device described in Patent Document 2 acquires the difference between the first detection signal and the second detection signal at approximately the same position, thereby detecting damage to the wire rope that has occurred after the first measurement while canceling out noise data from the wire rope. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6805986 [Patent Document 2] International Publication No. 2019 / 150539 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the inherent magnetic characteristics of a wire rope may change over time. In such cases, even if the wire rope inspection device described in Patent Document 2 acquires the difference between a first detection signal measured before damage to the wire rope occurs and a second detection signal measured later to detect the damage, it may not be able to accurately cancel (reduce) noise data due to the inherent magnetic characteristics of the wire rope. Furthermore, when a pair of detector coils (differential coils) is configured to be separable and a coil loop is formed in each of the pair of divided detector coils, as in the detector coil formed by a pair of saddle-shaped coils described in Patent Document 1, the inherent magnetic characteristics of the wire rope, whose magnetic field direction is perpendicular to the extension direction of the wire rope, are detected as noise data. If such inherent magnetic characteristics of the wire rope, whose magnetic field direction is perpendicular to the extension direction of the wire rope, change over time, the method of acquiring the difference described in Patent Document 2 cannot accurately cancel noise data due to the inherent magnetic characteristics of the wire rope. Therefore, when detecting the change in magnetic flux of a wire rope using a pair of divisible detection coils, each of which forms a coil loop, it is desirable to reduce the noise components caused by the inherent magnetic characteristics of the wire rope, which has a magnetic field oriented perpendicular to the direction in which the wire rope extends.

[0007] This invention has been made to solve the above-mentioned problems, and one object of this invention is to provide a wire rope inspection system that can reduce noise components caused by the inherent magnetic characteristics of a wire rope, which has a magnetic field oriented in a direction perpendicular to the direction in which the wire rope extends, when detecting changes in the magnetic flux of the wire rope using a pair of divisible detection coils, each of which forms a coil loop. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a wire rope inspection system in one aspect of the present invention includes an excitation unit that applies a magnetic field to the wire rope, a first differential coil that detects a change in magnetic flux in the wire rope to which the magnetic field has been applied by the excitation unit, and a second differential coil that is provided separately from the first differential coil and detects a change in magnetic flux in the wire rope to which the magnetic field has been applied by the excitation unit, and is equipped with a detection unit that outputs detection signals from the first differential coil and the second differential coil, and a control unit that acquires the difference between the detection signal from the first differential coil of the detection unit and the detection signal from the second differential coil, wherein each of the first differential coil and the second differential coil has a pair of detection coils that can be separated along a direction perpendicular to the direction in which the wire rope extends, and the pair of detection coils in each of the first differential coil and the second differential coil each form a coil loop and are combined with each other to wind around the wire rope. Note that the term "direction perpendicular to the direction in which the wire rope extends" is used here as a broad concept that also includes directions that intersect with the direction in which the wire rope extends but deviate from the direction perpendicular to the direction in which the wire rope extends. [Effects of the Invention]

[0009] As described above, a wire rope inspection system according to one aspect of the present invention includes a first differential coil that detects a change in magnetic flux in a wire rope when a magnetic field is applied by an excitation unit, and a second differential coil that is provided separately from the first differential coil and detects a change in magnetic flux in the wire rope when a magnetic field is applied by the excitation unit, and a detection unit that outputs detection signals from the first differential coil and the second differential coil. The wire rope inspection system according to one aspect of the present invention also includes a control unit that acquires a difference between the detection signal from the first differential coil and the detection signal from the second differential coil of the detection unit. Furthermore, a pair of detector coils in each of the first differential coil and the second differential coil each form a coil loop and are wound around the wire rope by combining with each other. Here, when the position at which the magnetic flux of the wire rope is measured is changed, the magnetic flux indicating an abnormal portion where a change in the cross-sectional area or composition of the wire rope has occurred, such as a broken wire, a kink, rust, or the attachment of foreign matter, changes relatively sharply. On the other hand, magnetic flux due to the inherent magnetic properties of a wire rope, which has a magnetic field oriented perpendicular to the wire rope's extension direction, changes relatively slowly when the measurement position is changed. Therefore, the amount of change in magnetic flux due to the inherent magnetic properties of the wire rope fluctuates less when the measurement position on the wire rope is changed than the amount of change in magnetic flux due to an abnormality. In consideration of this, the present invention includes a first differential coil that detects the amount of change in magnetic flux in the wire rope when a magnetic field is applied by an excitation unit, and a second differential coil that is provided separately from the first differential coil and detects the amount of change in magnetic flux in the wire rope when a magnetic field is applied by the excitation unit. As a result, when the amount of change in magnetic flux is detected by a pair of detection coils that form a coil loop at each of the two measurement positions of the first differential coil and the second differential coil, which are provided separately from each other, by obtaining the difference between the detection signals from the first differential coil and the second differential coil, it is possible to cancel (reduce) the noise component that indicates the magnetic properties of the wire rope when the magnetic field is oriented perpendicular to the wire rope's extension direction while suppressing cancellation of the component that indicates the abnormality contained in each detection signal.As a result, when detecting the change in magnetic flux of a wire rope using a pair of divisible detection coils, each of which forms a coil loop, it is possible to reduce noise components caused by the inherent magnetic characteristics of the wire rope, which has a magnetic field oriented perpendicular to the direction in which the wire rope extends. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the overall configuration of a wire rope inspection system according to a first embodiment. [Figure 2] 1 is a block diagram showing the overall configuration of a wire rope inspection system according to a first embodiment. [Figure 3] 2 is a diagram showing the arrangement of a magnetic conditioning unit, a magnetic excitation unit, and a detection unit in the wire rope inspection device of the first embodiment. FIG. [Figure 4] 4 is a schematic diagram for explaining the configuration of a first differential coil and a second differential coil of a detection unit. FIG. [Figure 5] 4 is a cross-sectional view in the XZ plane for explaining the separation distance between the first differential coil and the second differential coil. FIG. [Figure 6] 10A and 10B are diagrams for explaining generation of a magnetic flux waveform based on a difference between detection signals. [Figure 7] FIG. 2 is a flowchart for explaining the control process performed by the wire rope inspection system of the first embodiment. [Figure 8] FIG. 10 is a block diagram showing the overall configuration of a wire rope inspection system according to a second embodiment. [Figure 9] 10 is a diagram for explaining the arrangement of a first differential coil and a second differential coil according to a second embodiment. FIG. [Figure 10] 10A and 10B are cross-sectional views of the first differential coil and the second differential coil in the YZ plane of the second embodiment, where (A) is a cross-sectional view showing the first differential coil, and (B) is a cross-sectional view showing the second differential coil. [Figure 11] FIG. 10 is a block diagram showing the overall configuration of a wire rope inspection system according to a third embodiment. [Figure 12]10A and 10B are diagrams for explaining the arrangement of first differential coils and second differential coils according to the third embodiment. [Figure 13] 10 is a diagram showing a cross-sectional view of the first differential coil and the second differential coil in the YZ plane according to the third embodiment. FIG. [Figure 14] 1A and 1B are cross-sectional views in the YZ plane of a first differential coil and a second differential coil according to a first modified example of the present invention, where (A) is a cross-sectional view showing the first differential coil, and (B) is a cross-sectional view showing the second differential coil. [Figure 15] 10 is a schematic diagram for explaining a first differential coil and a second differential coil according to a second modified example of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0012] [First embodiment] First, the configuration of a wire rope inspection system 100 according to a first embodiment of the present invention will be described with reference to Figures 1 to 6. In the following description, "orthogonal" means intersecting at an angle of 90 degrees or close to 90 degrees. Furthermore, "parallel" includes parallel and approximately parallel.

[0013] (Wire rope inspection system configuration) As shown in FIG. 1, the wire rope inspection system 100 includes a wire rope inspection device 101 and a processing device 102. The wire rope inspection device 101 detects changes in magnetic flux in the wire rope W to be inspected. The wire rope inspection device 101 is configured to transmit measurement results (detection signals) measured by detecting the changes in magnetic flux in the wire rope W to the processing device 102. The processing device 102 executes processing to determine abnormal portions of the wire rope W based on the measurement results of the wire rope W by the wire rope inspection device 101. An abnormal portion is a portion of the wire rope W where a change in the cross-sectional area or composition has occurred, such as a broken wire, a kink, rust, or the attachment of foreign matter. The processing device 102 also displays the measurement results of the wire rope W by the wire rope inspection device 101 and the determination results of the abnormal portion.

[0014] The wire rope inspection system 100 inspects the wire rope W installed in the elevator 103. Specifically, the wire rope inspection system 100 is a system for inspecting abnormal parts of the wire rope W of the elevator 103 that is the inspection target. Furthermore, the wire rope inspection system 100 is a system that can detect abnormalities in the wire rope W that are difficult to detect visually by using a total magnetic flux method that measures the magnetic flux inside the wire rope W. If the wire rope W contains an abnormal part, the magnetic flux in the abnormal part will be different from that in a normal part. Unlike methods that measure only leakage magnetic flux from abnormal parts on the surface of the wire rope W, the total magnetic flux method is a method that can also detect abnormal parts inside the wire rope W.

[0015] (Elevator configuration) As shown in FIG. 1, elevator 103 includes a car 103a, sheaves 103b and 103c, a control device 103d, and a wire rope W. Elevator 103 is configured such that a sheave 103b (pulley) provided on a hoist rotates to wind up the wire rope W, thereby moving car 103a carrying people, cargo, and the like, in the vertical direction. Furthermore, elevator 103 is, for example, a double-wrap (full-wrap) rope-type elevator equipped with two sheaves, 103b and 103c. The double-wrap system is a structure in which wire rope W is guided from sheave 103b of the hoist to sheave 103c, which is a deflector pulley, and then returned to sheave 103b of the hoist, thereby looping wire rope W twice around sheave 103b. Control device 103d includes a control panel that controls the operation of each part of elevator 103. The control device 103d includes a wireless communication module and is configured to be able to communicate with the processing device 102.

[0016] The wire rope W is a long, magnetic body formed by weaving (e.g., strand weaving) magnetic wire material. To prevent the wire rope W from breaking due to deterioration, its condition (presence or absence of abnormalities) is inspected by a wire rope inspection device 101. If, as a result of measuring the magnetic flux of the wire rope W, it is determined that the degree of deterioration has exceeded a predetermined standard, the wire rope W is replaced by an inspector.

[0017] The wire rope W is arranged to extend in the X direction (see FIG. 3) at the position of the wire rope inspection device 101. The wire rope inspection device 101 measures the magnetic flux of the wire rope W while moving along the surface of the wire rope W in the direction in which the wire rope W extends (X direction) relative to the wire rope W. In the case where the wire rope W itself moves, such as the wire rope W used in the elevator 103, the wire rope inspection device 101 measures the magnetic flux of the wire rope W while moving the wire rope W in the X2 direction. In this way, the wire rope inspection device 101 measures the magnetic flux at each position in the X direction of the wire rope W, thereby inspecting the wire rope W for damage at each position in the X direction.

[0018] (Configuration of wire rope inspection device) 2 and 3, wire rope inspection device 101 includes a magnetic conditioning unit 10, a magnetic excitation unit 20, a detection unit 30, and a control board 40. Wire rope inspection device 101 is disposed between sheave 103b and sheave 103c of elevator 103 so as to inspect wire rope W.

[0019] The magnetic conditioning unit 10 adjusts the direction of magnetization of the wire rope W by applying a magnetic field to the wire rope W in advance. The magnetic conditioning unit 10 is arranged upstream (X1 direction side) of the detection unit 30 in the movement direction of the wire rope W. For example, the magnetic conditioning unit 10 is a permanent magnet. The magnetic conditioning unit 10 also includes a pair of magnetic conditioning units 10a and 10b. The pair of magnetic conditioning units 10a and 10b are arranged on both sides of the short direction of the wire rope W (the direction perpendicular to the extension direction of the wire rope W, the Z direction) so as to sandwich the wire rope W. Specifically, the magnetic conditioning unit 10a is arranged on the Z1 direction side of the wire rope W. The magnetic conditioning unit 10b is arranged on the Z2 direction side of the wire rope W. The magnetic conditioning unit 10 is arranged so that the north pole (hatched) of magnetic conditioning unit 10a facing in the Z2 direction and the north pole (hatched) of magnetic conditioning unit 10b facing in the Z1 direction face each other across the wire rope W. Magnetic conditioning units 10a and 10b are configured to be able to apply a relatively strong magnetic field to the wire rope W in order to adjust the magnetization direction of the wire rope W to a substantially uniform direction.

[0020] The excitation unit 20 is configured to apply a magnetic field (magnetic flux) to the wire rope W so as to excite (vibrate) the magnetization state of the wire rope W. Specifically, the excitation unit 20 includes an excitation coil 21. The excitation coil 21 is provided so as to wind around the wire rope W along the direction in which the wire rope W extends (the X direction). Specifically, in the first embodiment, the excitation coil 21 is provided so as to wind around the wire rope W outside a first differential coil 31 and a second differential coil 32 of a detection unit 30, which will be described later, so as to cover both the first differential coil 31 and the second differential coil 32.

[0021] When an AC current is passed through excitation coil 21, it generates a magnetic flux (magnetic field) inside the coil (inside the loop of the coil) along the extension direction (X direction) of wire rope W. Specifically, an AC current (excitation current) having a predetermined frequency is passed through excitation coil 21 of excitation unit 20 under the control of processing unit 41 of control board 40, which will be described later, and a magnetic field that oscillates in the extension direction (X direction) of wire rope W is applied. That is, in wire rope W, the magnetic field (magnetic flux) previously adjusted by magnetic conditioning unit 10 is oscillated by excitation unit 20 so that a magnetic field in the X1 direction and a magnetic field in the X2 direction periodically appear.

[0022] <Configuration of the detection unit> In the first embodiment, the detection unit 30 includes a first differential coil 31 and a second differential coil 32. The first differential coil 31 and the second differential coil 32 are each formed by a conductor pattern provided on a flexible substrate. The first differential coil 31 and the second differential coil 32 may be provided separately on a common substrate, or may be provided on two different substrates.

[0023] The first differential coil 31 and the second differential coil 32 move together relative to the wire rope W and detect the amount of change in the magnetic flux of the wire rope W to which a magnetic field has been applied in advance (after being magnetized) by the magnetization unit 10 and to which a magnetic field has been applied (excited) to vibrate by the magnetization unit 20. In the wire rope inspection system 100 of the first embodiment, each of the first differential coil 31 and the second differential coil 32 detects the change in the magnetic flux of the wire rope W while moving relative to the wire rope W by detecting the change in the magnetic flux of the wire rope W moving in the X2 direction.

[0024] As shown in FIG. 4, the first differential coil 31 is wound around the wire rope W along the direction in which the wire rope W extends.

[0025] Specifically, the first differential coil 31 includes a pair of detector coils 31a and 31b. The pair of detector coils 31a and 31b is configured to be separable along a direction (Z direction) perpendicular to the direction in which the wire rope W extends. The detector coils 31a and 31b of the first differential coil 31 are a pair of independent saddle-shaped coils each forming a coil loop. Specifically, the detector coil 31a of the first differential coil 31 is disposed on the Z1 direction side of the wire rope W, and the detector coil 31b is disposed on the Z2 direction side. The detector coils 31a and 31b are each disposed to cover half a circumference (180 degrees) of the wire rope W. The first differential coil 31 is configured such that the two saddle-shaped coils are wound around the entire circumference of the wire rope W along the direction in which the wire rope W extends (X direction) by combining the detector coils 31a and 31b with each other. In this specification, the term "winding" is used to refer not only to winding (wrapping) one or more times, but also to winding an angle less than one time (for example, half a turn).

[0026] The detection signal output from the first differential coil 31 is a signal indicating the sum of the outputs of the detector coils 31a and 31b. Specifically, by combining the detector coils 31a and 31b, which are a pair of saddle-shaped coils, the first differential coil 31 serves as a differential coil that detects the amount of change in magnetic flux in the wire rope W to which a magnetic field is applied by the excitation unit 20. That is, the combination of the detector coils 31a and 31b forms two coil loops, one on the X1 direction side and the other on the X2 direction side, that are differentially connected and wound around the wire rope W. Therefore, the detection signal output from the first differential coil 31 corresponds to the difference between the magnetic flux detected by the coil loop on the X1 direction side formed by the detector coils 31a and 31b and the magnetic flux detected by the coil loop on the X2 direction side. Therefore, the first differential coil 31 detects the amount of change in magnetic flux in the wire rope W in a predetermined section corresponding to the width of the first differential coil 31 in the X direction. In this way, the first differential coil 31 is configured to reduce the effects of shaking (noise components caused by vibration of the wire rope W) in the short direction of the wire rope W (the direction perpendicular to the direction in which the wire rope W extends: the direction along the YZ plane) by adding the outputs of the detection coils 31a and 31b, which are a pair of saddle-shaped coils.

[0027] The second differential coil 32 is provided separately from the first differential coil 31 along the extension direction of the wire rope W and is wound around the wire rope W. The second differential coil 32 has a configuration similar to that of the first differential coil 31. That is, the second differential coil 32 has a pair of detector coils 32a and 32b, each of which forms a coil loop. Like the first differential coil 31, the pair of detector coils 32a and 32b of the second differential coil 32 is configured to be separable along a direction (Z direction) perpendicular to the extension direction of the wire rope W. In the first embodiment, the number of turns of the pair of detector coils 31a and 31b in the first differential coil 31 is approximately equal to the number of turns of the pair of detector coils 32a and 32b in the second differential coil 32. Note that while FIG. 4 illustrates an example in which the number of turns in the coil loop of the saddle-shaped coil is one in the first differential coil 31 and the second differential coil 32, the number of turns may be multiple.

[0028] Similarly to the first differential coil 31, the second differential coil 32 is configured by combining a detector coil 32a, which is a saddle-shaped coil located on the Z1-direction side of the wire rope W, with a detector coil 32b, which is a saddle-shaped coil located on the Z2-direction side, so that the pair of saddle-shaped coils are wound around the entire circumference of the wire rope W. Similarly to the first differential coil 31, the second differential coil 32 is configured by combining the detector coil 32a and the detector coil 32b, so that the second differential coil 32 serves as a differential coil that detects the amount of change in magnetic flux in the wire rope W to which a magnetic field is applied by the excitation unit 20. That is, the second differential coil 32 detects the amount of change in magnetic flux in the wire rope W in a predetermined section that corresponds to the width of the second differential coil 32 in the X direction.

[0029] In the first embodiment, the first differential coil 31 and the second differential coil 32 are arranged side by side along the direction in which the wire rope W extends (X direction). Specifically, the first differential coil 31 is arranged near the center position of the excitation coil 21 in the direction in which the wire rope W extends (X direction). The second differential coil 32 is arranged side by side on the downstream side (X2 direction side) of the first differential coil 31. Note that the term "near" the center position here is used as a broad concept that includes the center position itself.

[0030] 5, in the first embodiment, the first differential coil 31 and the second differential coil 32 are arranged so that their respective distances (d101 and d102) from the wire rope W are approximately equal. That is, the distance d101 between the inner surface of the first differential coil 31 and the outer surface of the wire rope W is approximately equal to the distance d102 between the inner surface of the second differential coil 32 and the outer surface of the wire rope W.

[0031] In the first embodiment, the first differential coil 31 and the second differential coil 32 are disposed at a distance substantially equal to the distances d101 and d102 from the wire rope W. That is, the distance d103 between the center position of the first differential coil 31 in the X direction and the center position of the second differential coil 32 in the X direction is configured to be substantially equal to the distances d101 and d102 from the wire rope W of the first differential coil 31 and the second differential coil 32.

[0032] For example, the first differential coil 31 and the second differential coil 32 are disposed at a position spaced apart by approximately 3 mm from the outer surface of the wire rope W. The distance d103 between the centers of the first differential coil 31 and the second differential coil 32 is also approximately 3 mm.

[0033] As described above, in the first embodiment, the first differential coil 31 and the second differential coil 32 are each separately wound along the extension direction (X direction) of the wire rope W, thereby detecting (measuring) changes in magnetic flux that penetrate the inside of the coil loops that wind around each wire rope W along the extension direction (X direction) of the wire rope W. Each of the first differential coil 31 and the second differential coil 32 is configured to output a detection signal by detecting, at each position (measurement position), the amount of change in magnetic flux (magnetic field) that is periodically changed over time by the excitation unit 20 (excitation coil 21). Specifically, the detection unit 30 outputs the detection signals from each of the first differential coil 31 and the second differential coil 32 to a signal acquisition unit 42 (see FIG. 4) of the control board 40, which will be described later.

[0034] As shown in FIG. 2, the control board 40 includes a processing unit 41, a signal acquisition unit 42, and a communication unit 43. The control board 40 controls each unit of the wire rope inspection device 101 through control processing by the processing unit 41. The processing unit 41 includes a processor such as a CPU (Central Processing Unit), a memory, an AD converter, and the like. The control board 40 controls the operation of the excitation unit 20 (excitation coil 21) based on a control signal from the processing unit 41. The signal acquisition unit 42 acquires (receives) a detection signal from the detection unit 30 (first differential coil 31 and second differential coil 32). The signal acquisition unit 42 includes an amplifier. The signal acquisition unit 42 then amplifies the acquired detection signal and outputs (transmits) it to the processing unit 41. The communication unit 43 is configured to be able to communicate with the processing device 102. The communication unit 43 includes a wireless communication module capable of wireless communication via wireless LAN, Bluetooth (registered trademark), or the like. The processing unit 41 outputs (transmits) the acquired detection signal to the processing device 102 via the communication unit 43. In particular, the processing unit 41 outputs the sum of the outputs of the pair of detection coils 31a and 31b of the first differential coil 31 as the detection signal of the first differential coil 31, and outputs the sum of the outputs of the pair of detection coils 32a and 32b of the second differential coil 32 as the detection signal of the second differential coil 32. Note that the connection between the wire rope inspection device 101 and the processing device 102 via the communication unit 43 may be a wired connection.

[0035] (Configuration of processing device) 2, the processing device 102 includes a control unit 50, a memory unit 60, a touch panel 70, and a communication unit 80. The processing device 102 is provided separately from the wire rope inspection device 101. The processing device 102 is, for example, a tablet terminal such as a tablet PC (Personal Computer) used by an inspection worker who inspects the wire rope W.

[0036] The control unit 50 controls each part of the processing device 102. The control unit 50 includes a processor such as a CPU, a memory, etc. The control unit 50 executes a process of determining an abnormal part of the wire rope W based on the measurement results (detection signals) of the wire rope W received via the communication unit 80. Details of the abnormal part determination process by the control unit 50 will be described later.

[0037] The memory unit 60 is, for example, a storage device including a flash memory. The memory unit 60 stores (preserves) information such as the acquired measurement results of the wire rope W and the determination results of abnormal portions of the wire rope W by the control unit 50. The memory unit 60 also stores a program for determining abnormal portions of the wire rope W, processing parameters, and the like.

[0038] The touch panel 70 displays information such as the measurement results of the wire rope W and the analysis results of the measurement results of the wire rope W (determination results of abnormal portions) by the control unit 50. The touch panel 70 also accepts input operations by the inspection operator.

[0039] The communication unit 80 is configured to be able to communicate with the wire rope inspection device 101 and the control device 103d of the elevator 103. The communication unit 80 is a communication interface. Specifically, the communication unit 80 includes a wireless communication module capable of wireless communication via wireless LAN, Bluetooth (registered trademark), etc. The processing device 102 receives the measurement results (detection signals) of the wire rope W by the wire rope inspection device 101 via the communication unit 80. Furthermore, when starting inspection of the wire rope W based on an input operation by an inspection operator, the processing device 102 transmits a signal indicating the start of inspection to the wire rope inspection device 101 and the elevator 103 (the control device 103d of the elevator 103) via the communication unit 80.

[0040] The processing device 102 is configured to acquire a signal indicating the position of the wire rope W along with the acquired detection signal (measurement result). The processing device 102 is configured to store the detection signal in association with position information indicating the position of the wire rope W corresponding to the detection signal. The position information of the wire rope W is acquired, for example, from the control device 103d of the elevator 103. The position information of the wire rope W may be acquired by a position sensor such as an encoder, or may be calculated based on the operating speed of the elevator 103 and the elapsed inspection time during which the inspection is performed.

[0041] (Processing to determine abnormal parts by processing device) Next, the process of determining an abnormal portion by the processing device 102 will be described with reference to FIG.

[0042] As shown in FIG. 6 , in the first embodiment, the control unit 50 of the processing device 102 acquires a detection signal from the first differential coil 31 and a detection signal from the second differential coil 32. Specifically, the control unit 50 sequentially acquires the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32, which are detected by measuring the moving wire rope W, in accordance with the movement (position change) of the wire rope W. Then, the control unit 50 acquires a difference between the acquired detection signal from the first differential coil 31 and the detection signal from the second differential coil 32. Specifically, the control unit 50 is configured to calculate the difference between the detection signals from the first differential coil 31 and the second differential coil 32 in real time in accordance with the movement of the wire rope W. The control unit 50 is configured to acquire a difference between the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32, which are detected at approximately the same timing.

[0043] In order to reduce electrical noise, the control unit 50 performs moving average processing on the acquired detection signals from each of the first differential coil 31 and the second differential coil 32 at predetermined intervals (e.g., 20 ms). The sampling frequency of the detection signals is, for example, 1 kHz. That is, the control unit 50 is configured to sample the average value of the detection signals acquired every 1 ms, including 10 ms before and after, every 1 ms. The control unit 50 is then configured to execute processing to calculate the difference between the detection signals from each of the first differential coil 31 and the second differential coil 32 for which moving average processing has been performed. The control unit 50 is configured to calculate the difference at a predetermined sampling period in response to the movement of the wire rope W and to generate a magnetic flux waveform in real time based on the calculated difference for determining whether an abnormal portion exists. The magnetic flux waveform is obtained by plotting the calculated difference between the detection signals from each of the first differential coil 31 and the second differential coil 32 at each predetermined sampling period.

[0044] Furthermore, because the distances d101 and d102 between the first differential coil 31 and the second differential coil 32 and the wire rope W are approximately equal to the distance d103 between the first differential coil 31 and the second differential coil 32, when the position of the abnormal portion of the wire rope W is the same as the center position of the first differential coil 31 in the X direction, the distance from the abnormal portion to the second differential coil 32 is √2 times the distance from the abnormal portion to the first differential coil 31. The change in magnetic flux indicating the abnormal portion has a weak amplitude and decays inversely proportional to the square of the distance. Therefore, the magnitude of the component indicating the abnormal portion in the detection signal from the second differential coil 32 is approximately half the magnitude of the component indicating the abnormal portion in the detection signal from the first differential coil 31. Therefore, even when the difference between the detection signals from the first differential coil 31 and the second differential coil 32 is obtained, the component indicating the abnormal portion is detected without being removed.

[0045] On the other hand, the inherent magnetic characteristics of the wire rope W reflect the magnetic flux leaking from the wire rope W due to the magnetization magnetic field generated by the magnetization unit 10 and the excitation magnetic field generated by the excitation coil 21 (excitation unit 20). The period of change in the inherent magnetic characteristics of the wire rope W is considered to be at least longer than the length of the excitation coil 21 in the X direction (the direction in which the wire rope W extends). The length of the excitation coil 21 in the X direction is also longer than the period T (one pitch, see FIG. 9) of the wire rope W. In other words, since the period of change in the inherent magnetic characteristics of the wire rope W is sufficiently longer than the separation distance d103 between the first differential coil 31 and the second differential coil 32, the difference between the component of the inherent magnetic characteristics of the wire rope W in the detection signal from the first differential coil 31 and the component of the inherent magnetic characteristics of the wire rope W in the detection signal from the second differential coil 32 becomes small. Therefore, when the difference between the detection signals from the first differential coil 31 and the second differential coil 32 is calculated, the component of the inherent magnetic characteristics of the wire rope W is reduced (canceled).

[0046] The control unit 50 then detects an abnormal portion of the wire rope W based on the generated magnetic flux waveform. For example, the control unit 50 determines that a portion of the wire rope W where the value of the magnetic flux waveform is greater than a predetermined judgment threshold is an abnormal portion of the wire rope W. The judgment threshold may be set by selecting from multiple candidates based on an input operation by the inspection operator. The control unit 50 acquires position information indicating the position of the wire rope W that has been determined to be an abnormal portion.

[0047] The control unit 50 then displays the generated abnormal portion determination result (analysis result) on the touch panel 70. For example, the control unit 50 causes the touch panel 70 to display a numerical value indicating the position of the wire rope W determined to be an abnormal portion. The control unit 50 causes the touch panel 70 to display position information indicating the position of the abnormal portion of the wire rope W, for example, by using a distance from the position where the inspection of the wire rope W began, which is set to 0. The control unit 50 may also display the value of the magnetic flux waveform when the wire rope W is determined to be an abnormal portion, in addition to the position of the wire rope W. The control unit 50 may also display a magnetic flux waveform based on the difference between the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32 on the touch panel 70 so that the magnetic flux waveform can be visually recognized.

[0048] (Control processing method of the wire rope inspection system according to the first embodiment) Next, the control processing by the wire rope inspection system 100 of the first embodiment will be described with reference to Fig. 8. This control processing is executed by the wire rope inspection device 101 and processing device 102 of the wire rope inspection system 100. That is, steps 602 and 603 represent control processing by the processing unit 41 of the wire rope inspection device 101. Then, steps 601 and 604 to 606 represent control processing by the control unit 50 of the processing device 102.

[0049] First, in step 601, an input operation to start inspection of the wire rope W is accepted. Specifically, inspection of the wire rope W is started based on the input operation on the touch panel 70. Then, a signal indicating the start of inspection is transmitted to the control device 103d of the elevator 103 and the processing unit 41 of the wire rope inspection device 101.

[0050] Next, in step 602, a magnetic field is applied to the wire rope W. Then, in step 603, a detection signal is acquired by detecting the amount of change in magnetic flux of the wire rope W to which the magnetic field has been applied while moving relative to the wire rope W. Specifically, while the wire rope W is moved relative to the first differential coil 31 and the second differential coil 32 of the detection unit 30, detection signals are acquired from each of the first differential coil 31 and the second differential coil 32.

[0051] Next, in step 604, the difference between the acquired detection signals from the first differential coil 31 and the second differential coil 32 is calculated. Then, a magnetic flux waveform is generated based on the calculated difference. Then, in step 605, an abnormal portion of the wire rope W is determined based on the calculated difference. Next, in step 606, the determination result of the abnormal portion is displayed on the touch panel 70 so that information indicating the position of the wire rope W determined to be an abnormal portion can be confirmed.

[0052] (Effects of the first embodiment) The wire rope inspection system 100 of the first embodiment can provide the following effects.

[0053] As described above, the wire rope inspection system 100 of the first embodiment includes a first differential coil 31 that detects a change in magnetic flux in the wire rope W when a magnetic field is applied by the excitation unit 20, and a second differential coil 32 that is provided separately from the first differential coil 31 and detects a change in magnetic flux in the wire rope W when a magnetic field is applied by the excitation unit 20, and is equipped with a detection unit 30 that outputs detection signals from the first differential coil 31 and the second differential coil 32. The wire rope inspection system 100 of the first embodiment is also equipped with a control unit 50 that acquires the difference between the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32 of the detection unit 30. Furthermore, the pair of detector coils 31a and 31b and the pair of detector coils 32a and 32b in each of the first differential coil 31 and the second differential coil 32 each form a coil loop and are wound around the wire rope by combining with each other. Here, when the position at which the magnetic flux of the wire rope W is measured is changed, the magnetic flux indicating an abnormal portion, where a change in the cross-sectional area or composition of the wire rope W has occurred, such as a broken wire, a kink, rust, or the attachment of foreign matter, changes relatively sharply. On the other hand, the magnetic flux due to the inherent magnetic characteristics of the wire rope W, which has a magnetic field oriented perpendicular to the extension direction of the wire rope W, changes relatively gradually when the measurement position is changed. Therefore, the amount of change in magnetic flux due to the inherent magnetic characteristics of the wire rope W fluctuates less with a change in the measurement position relative to the wire rope W than the amount of change in magnetic flux due to an abnormal portion. In consideration of this, the first embodiment includes a first differential coil 31 that detects the amount of change in magnetic flux in the wire rope W when a magnetic field is applied by the magnetic excitation unit 20, and a second differential coil 32 that is provided separately from the first differential coil 31 and detects the amount of change in magnetic flux in the wire rope W when a magnetic field is applied by the magnetic excitation unit 20.As a result, when a change in magnetic flux is detected by a pair of detector coils each forming a coil loop at two different measurement positions of the first differential coil 31 and the second differential coil 32, which are provided separately from each other, by obtaining the difference between the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32, it is possible to suppress cancellation of components indicating abnormalities contained in each detection signal, while canceling (reducing) noise components that indicate magnetic characteristics specific to the wire rope W, whose magnetic field is oriented in a direction perpendicular to the extension direction of the wire rope W. As a result, when a change in magnetic flux of the wire rope W is detected by a pair of separable detector coils 31a and 31b (detector coils 32a and 32b), each forming a coil loop, it is possible to reduce noise components caused by magnetic characteristics specific to the wire rope W, whose magnetic field is oriented in a direction perpendicular to the extension direction of the wire rope W.

[0054] Furthermore, since each of the first differential coil 31 and the second differential coil 32 has a pair of separable detector coils 31a and 31b and detector coils 32a and 32b, the first differential coil 31 and the second differential coil 32 can be easily attached to a midpoint of the wire rope W without having to be attached by inserting them into the end of the wire rope W. Therefore, the first differential coil 31 and the second differential coil 32 can be easily attached to a wire rope W that has already been installed.

[0055] Furthermore, in the first embodiment, the following additional effects can be obtained by configuring as follows.

[0056] That is, in the first embodiment, the number of turns of the pair of detector coils 31a and 31b in the first differential coil 31 is approximately equal to the number of turns of the pair of detector coils 32a and 32b in the second differential coil 32. With this configuration, it is possible to reduce the difference between the component of the magnetic characteristics inherent to the wire rope W contained in the detection signal from the first differential coil 31 and the component of the magnetic characteristics inherent to the wire rope W contained in the detection signal from the second differential coil 32. As a result, when the difference between the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32 is obtained, it is possible to accurately reduce noise components caused by the magnetic characteristics inherent to the wire rope W.

[0057] Furthermore, in the first embodiment, the pair of detector coils 31a and 31b and the pair of detector coils 32a and 32b in each of the first differential coil 31 and the second differential coil 32 include a pair of saddle-shaped coils that can be separated along a direction (Z direction) perpendicular to the direction (X direction) in which the wire rope W extends. With this configuration, since each of the first differential coil 31 and the second differential coil 32 includes a pair of saddle-shaped coils (detector coils 31a and 31b, and detector coils 32a and 32b), a differential coil wound around the wire rope W can be formed by combining the pair of saddle-shaped coils in each of the first differential coil 31 and the second differential coil 32. Here, if each of the first differential coil 31 and the second differential coil 32 is formed as a solenoid coil with a winding wound helically along the direction in which the wire rope W extends, it is necessary to separate the entire winding that forms the coil in order to form the separate coil. In this case, multiple terminals are required to connect the separated windings, which is considered to complicate the device configuration. In contrast, in the first embodiment, the first differential coil 31 and the second differential coil 32 each include a pair of saddle-shaped coils. This prevents the device configuration from becoming complicated due to the need for a separable configuration, compared to when the first differential coil 31 and the second differential coil 32 are each configured as solenoid coils. Furthermore, by using saddle-shaped coils for the pair of detector coils 31a and 31b and the pair of detector coils 32a and 32b, the coils can be arranged to conform to the shape of the wire rope W. Therefore, compared to when the pair of detector coils 31a and 31b and the pair of detector coils 32a and 32b are each configured as flat coils, the pair of saddle-shaped coils can more accurately detect the inherent magnetic characteristics of the wire rope W, which has a magnetic field oriented in a direction perpendicular to the extension direction of the wire rope W. As a result, by using saddle-shaped coils for the pair of detector coils 31a and 31b and the pair of detector coils 32a and 32b, the noise components caused by the inherent magnetic characteristics of the wire rope W can be more accurately reduced.

[0058] Furthermore, in the first embodiment, the first differential coil 31 and the second differential coil 32 are configured to output detection signals while moving integrally relative to the wire rope W, and the control unit 50 is configured to calculate in real time the difference between the detection signal from the first differential coil 31, which is moving relative to the wire rope W, and the detection signal from the second differential coil 32, which is moving integrally with the first differential coil 31 relative to the wire rope W, in accordance with the relative movement of the first differential coil 31 and the second differential coil 32 with respect to the wire rope W. With this configuration, the first differential coil 31 and the second differential coil 32 output detection signals while moving integrally relative to the wire rope W. Therefore, unlike when the first differential coil 31 and the second differential coil 32 output detection signals while moving separately relative to the wire rope W, it is possible to suppress variations in the calculated difference due to misalignment between the first differential coil 31 and the second differential coil 32. This allows for accurate detection of abnormal portions of the wire rope W. Furthermore, because the difference between the detection signal from the first differential coil 31 and the detection signal from the second differential coil 32 is calculated in real time, the inspector performing the inspection can confirm the amount of change in magnetic flux in the wire rope W in a state in which noise components resulting from the inherent magnetic properties have been reduced while measuring the wire rope W. Therefore, the inspector can determine whether or not there is an abnormal part while inspecting the wire rope W, and can easily confirm any part of the wire rope W that has been determined to be abnormal.

[0059] Furthermore, in the first embodiment, the first differential coil 31 and the second differential coil 32 are arranged side by side along the extension direction of the wire rope W. This configuration can reduce the difference in the distances (d101 and d102) between the first differential coil 31 and the second differential coil 32 and the wire rope W. This can reduce the difference in the components of the magnetic characteristics inherent to the wire rope W in the detection signals from the first differential coil 31 and the second differential coil 32, thereby accurately reducing noise components caused by the magnetic characteristics inherent to the wire rope W.

[0060] Furthermore, in the first embodiment, the first differential coil 31 and the second differential coil 32 are arranged so that their respective distances (d101 and d102) from the wire rope W are approximately equal, and are also arranged so that they are spaced apart from each other by a distance approximately equal to their respective distances (d101 and d102) from the wire rope W. With this configuration, the first differential coil 31 and the second differential coil 32 are arranged so that their respective distances (d101 and d102) from the wire rope W are approximately equal, which can further reduce the difference in the components of the magnetic properties inherent to the wire rope W in the detection signals from the first differential coil 31 and the second differential coil 32. Furthermore, since the first differential coil 31 and the second differential coil 32 are disposed at a distance substantially equal to their respective separation distances (d101 and d102) from the wire rope W, when the position of the abnormal portion of the wire rope W is the same as the center position of the first differential coil 31 in the X direction, the distance from the abnormal portion to the second differential coil 32 is √2 times the distance from the abnormal portion to the first differential coil 31. Therefore, the signal component indicating the abnormal portion in the detection signal attenuates in proportion to the square of the distance, and therefore the signal component indicating the abnormal portion detected in the second differential coil 32 is substantially half the magnitude of the signal component indicating the abnormal portion detected in the first differential coil 31. As a result, when the difference between the detection signals from the first differential coil 31 and the second differential coil 32 is obtained, the signal component indicating the abnormal portion can be prevented from becoming too small, and noise components due to the inherent magnetic characteristics of the wire rope W can be accurately reduced.

[0061] Moreover, in the first embodiment, the excitation unit 20 includes an excitation coil 21 wound around the wire rope W outside the first differential coil 31 and the second differential coil 32 so as to cover both the first differential coil 31 and the second differential coil 32, and when an AC current is passed through the excitation coil 21, the excitation coil 21 applies a magnetic field that oscillates along the extension direction (X direction) of the wire rope W, and one of the first differential coil 31 and the second differential coil 32 is disposed near the center position of the excitation coil 21 in the extension direction of the wire rope W. Here, the magnetic field applied by the excitation coil 21 wound around the wire rope W has curved elliptical magnetic field lines, and therefore, near the center position of the excitation coil 21 in the extension direction of the wire rope W, the direction of the magnetic field applied by the excitation coil 21 is closest to the extension direction (X direction) of the wire rope W. Therefore, by arranging one of the first differential coil 31 and the second differential coil 32 near the center position of the excitation coil 21 in the direction in which the wire rope W extends, the direction of the magnetic field applied by the excitation coil 21 can be set to a direction that perpendicularly penetrates the coil loops of the first differential coil 31 and the second differential coil 32 that are wound around the wire rope W. As a result, the detection sensitivity (detection accuracy) of the acquired detection signal can be improved.

[0062] [Second embodiment] The configuration of a wire rope inspection system 200 according to a second embodiment will be described with reference to Figures 8 to 10. Unlike the first embodiment in which the first differential coil 31 and the second differential coil 32 of the detection unit 30 are spaced apart by distances approximately equal to the separation distances d101 and d102 from the wire rope W, in this second embodiment, the first differential coil 231 and the second differential coil 232 are spaced apart by a distance that is one-fourth the twist (strand) period T (one pitch) of the wire rope W. Note that in the figures, components similar to those in the first embodiment are denoted by the same reference numerals and will not be described again.

[0063] (Configuration of wire rope inspection system according to second embodiment) As shown in Fig. 8, a wire rope inspection system 200 according to the second embodiment includes a wire rope inspection device 201 and a processing device 202. The wire rope inspection device 201 includes a magnetic conditioning unit 10, a magnetic excitation unit 20, a detection unit 230, and a control board 40. The configurations of the magnetic conditioning unit 10, the magnetic excitation unit 20, and the control board 40 are the same as those in the first embodiment.

[0064] The detection unit 230 includes a first differential coil 231 and a second differential coil 232. As in the first embodiment, the first differential coil 231 includes separable detector coils 231a and 231b. Similarly, the second differential coil 232 includes separable detector coils 232a and 232b.

[0065] Similar to the first embodiment, the first differential coil 231 is disposed at the center of the excitation coil 21 in the X direction. The detector coils 231a and 231b include saddle-shaped coils. The detector coils 231a and 231b, which are saddle-shaped coils, are combined to form the first differential coil 231, which is wound around the wire rope W and serves as a differential coil that detects the amount of change in magnetic flux in the wire rope W to which a magnetic field is applied by the excitation unit 20. Similarly, the detector coils 232a and 232b of the second differential coil 232 each include a saddle-shaped coil. The detector coils 232a and 232b are combined to form the second differential coil 232, which is wound around the wire rope W and serves as a differential coil that detects the amount of change in magnetic flux in the wire rope W to which a magnetic field is applied by the excitation unit 20.

[0066] As shown in FIG. 9 , the second differential coil 232 is disposed at a predetermined distance d201 in the X2 direction relative to the first differential coil 231. Similar to the first embodiment, the distance between the first differential coil 231 and the second differential coil 232 is approximately equal. The wire rope W has a structure in which strands each made of a plurality of wires are twisted together. For example, the wire rope W is a six-strand rope made of six strands twisted together. The wire rope W is configured such that one strand makes one turn in the circumferential direction of the wire rope W per period T (per pitch). The strands of the wire rope W are twisted clockwise along the X direction. The distance d201 between the first differential coil 231 and the second differential coil 232 is a distance that is one-fourth of the twist period T of the wire rope W.

[0067] 10, the first differential coil 231 is configured so that the detector coil 231a and the detector coil 231b can be separated along the Z direction, similar to the first differential coil 31 of the first embodiment. In addition, in the second embodiment, the second differential coil 232 is configured so that it can be separated along a direction rotated by a predetermined angle from the direction in which the first differential coil 231 is separated (Z direction) in the twist rotation direction (clockwise) of the wire rope W, depending on the ratio of the separation distance d201 between the first differential coil 231 and the second differential coil 232 to the twist period T of the spirally twisted wire rope W.

[0068] Specifically, the separation distance d201 between the second differential coil 232 and the first differential coil 231 is one-fourth of the period T. Therefore, the second differential coil 232 is divided along a direction (Y direction) rotated 90 degrees (one-fourth of one rotation) in the twist rotation direction of the wire rope W from the direction (Z direction) in which the first differential coil 231 is divided. That is, in the second embodiment, the second differential coil 232 is configured so that the detector coils 232a and 232b can be divided along the Y direction. Note that, when the first differential coil 231 and the second differential coil 232 are integrally configured, a rotation mechanism may be provided for the second differential coil 232 so that the first differential coil 231 and the second differential coil 232 are integrally divided along the Z direction after the second differential coil 232 is rotated 90 degrees around the axis of the wire rope W. This allows the detector 230 to be integrally detachable from the wire rope W.

[0069] The processing device 202 includes a control unit 250, a memory unit 60, a touch panel 70, and a communication unit 80. Similar to the processing device 102 according to the first embodiment, the processing device 202 executes a process of determining an abnormal portion of the wire rope W based on the measurement results of the wire rope W by the wire rope inspection device 201.

[0070] Similar to the control unit 50 of the first embodiment, the control unit 250 of the processing device 202 acquires a detection signal from the first differential coil 231 and a detection signal from the second differential coil 232. Then, the control unit 250 acquires a difference between the acquired detection signal from the first differential coil 231 and the acquired detection signal from the second differential coil 232.

[0071] In the second embodiment, the control unit 250 calculates the difference between the detection signals from the first differential coil 231 and the second differential coil 232 while changing the time axis of either the detection signal from the first differential coil 231 or the detection signal from the second differential coil 232. Specifically, the control unit 250 acquires the difference while shifting the timing of the detection signal from the second differential coil 232 compared to the timing of the detection signal from the first differential coil 231, based on the relative speed of the detection unit 230 with respect to the wire rope W and the separation distance d201 between the first differential coil 231 and the second differential coil 232. In more detail, since the separation distance d201 is one-fourth of the period T, the control unit 250 is configured to calculate the difference with the detection signal from the first differential coil 231 while shifting the timing of the detection signal from the second differential coil 232 back by one-fourth of the time required for the wire rope W to move a distance equivalent to the period T (one pitch) at the moving speed of the wire rope W.

[0072] The control unit 250 executes a process of calculating a difference after executing a moving average process on the acquired detection signals, similar to the first embodiment. After acquiring the difference of the detection signals, the control unit 250 executes a process of determining an abnormal portion by the same process as the first embodiment, and displays the generated determination result (analysis result) of the abnormal portion on the touch panel 70. The other configurations of the second embodiment are similar to those of the first embodiment.

[0073] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0074] In the second embodiment, the second differential coil 232 is configured to be divided along a direction rotated a predetermined angle from the direction in which the first differential coil 231 is divided toward the twist rotation direction of the wire rope W, depending on the ratio of the separation distance d201 between the first differential coil 231 and the second differential coil 232 to the twist period T of the helically twisted wire rope W. With this configuration, the magnetic characteristics unique to the wire rope W change depending on the twist rotation of the helically twisted strands of the wire rope W. Therefore, even when the separation distance between the first differential coil 231 and the second differential coil 232 is increased, the difference between the component of the magnetic characteristics unique to the wire rope W included in the detection signal from the first differential coil 231 and the component of the magnetic characteristics unique to the wire rope W included in the detection signal from the second differential coil 232 can be reduced. Therefore, by obtaining the difference between the detection signals from the first differential coil 231 and the second differential coil 232, noise components due to the unique magnetic characteristics of the wire rope W can be further reduced. As a result, abnormalities in the wire rope W can be accurately identified.

[0075] The other effects of the second embodiment are the same as those of the first embodiment.

[0076] [Third embodiment] The configuration of a wire rope inspection system 300 according to the third embodiment will be described with reference to Figures 11 to 13. Unlike the first and second embodiments in which the first differential coil 31 (231) and the second differential coil 32 (232) are arranged side by side along the extension direction of the wire rope W, this third embodiment arranges the second differential coil 332 so as to cover the first differential coil 331. Note that in the figures, parts having the same configuration as those in the first and second embodiments are denoted by the same reference numerals and will not be described again.

[0077] (Configuration of wire rope inspection system according to the third embodiment) As shown in Fig. 11, a wire rope inspection system 300 according to the third embodiment includes a wire rope inspection device 301 and a processing device 102. The wire rope inspection device 301 includes a magnetic conditioning unit 10, a magnetic excitation unit 20, a detection unit 330, and a control board 40. The configurations of the magnetic conditioning unit 10, the magnetic excitation unit 20, and the control board 40 are the same as those in the first embodiment. The detection unit 330 includes a first differential coil 331 and a second differential coil 332.

[0078] 12, similarly to the first and second embodiments, the first differential coil 331 is disposed at the center of the excitation coil 21 in the X direction and includes a pair of detector coils 331a and 331b. The pair of detector coils 331a and 331b is configured to be separable along the Z direction. The detector coils 331a and 331b include saddle-shaped coils. The combination of the saddle-shaped detector coils 331a and 331b makes the first differential coil 331 a differential coil wound around the wire rope W and detecting the amount of change in magnetic flux in the wire rope W to which a magnetic field is applied by the excitation unit 20.

[0079] Similarly to the first differential coil 331, the second differential coil 332 includes a pair of saddle-shaped coils, namely, detector coils 332a and 332b. The pair of detector coils 332a and 332b are configured to be separable. Similarly to the first differential coil 331, the detector coils 332a and 332b, which are saddle-shaped coils, are combined to form the second differential coil 332, which is wound around the wire rope W and serves as a differential coil for detecting the amount of change in magnetic flux in the wire rope W to which a magnetic field is applied by the excitation unit 20.

[0080] In the third embodiment, the second differential coil 332 is wound around the wire rope W so as to cover the first differential coil 331 on the outer side of the first differential coil 331. Specifically, like the first differential coil 331, the second differential coil 332 is disposed at the center of the excitation coil 21 in the X direction. That is, the first differential coil 331 and the second differential coil 332 are positioned at the same position in the X direction of the wire rope W. The number of turns of the second differential coil 332 is equal to the number of turns of the first differential coil 331. The second differential coil 332 is configured to be divisible along the Z direction, which is common to the first differential coil 331.

[0081] 13 , the second differential coil 332 is spaced from the wire rope W by a distance d302 that is greater than the distance d301 that the first differential coil 331 is spaced from the wire rope W. Specifically, the second differential coil 332 is wound around the wire rope W to cover the first differential coil 331, while being spaced from the wire rope W by a distance (space d302) that is approximately twice the distance d301 that the first differential coil 331 is spaced from the wire rope W. More specifically, the space d302 between the inner surface of the second differential coil 332 and the outer surface of the wire rope W is approximately twice the distance d301 between the inner surface of the first differential coil 331 and the outer surface of the wire rope W. For example, when the space d301 between the first differential coil 331 and the wire rope W is 4 mm, the space d302 between the second differential coil 332 and the wire rope W is 8 mm.

[0082] The first differential coil 331 and the second differential coil 332 are configured to output detection signals, similarly to the first differential coil 31 and the second differential coil 32 of the first embodiment.

[0083] The processing device 102 includes a control unit 50, a storage unit 60, a touch panel 70, and a communication unit 80. The configuration of the processing device 102 is the same as that of the first embodiment. That is, like the first embodiment, the processing device 102 calculates the difference between the detection signals from the first differential coil 331 and the second differential coil 332 of the detection unit 330. Then, based on the calculated difference, the processing device 102 performs processing to determine an abnormal portion of the wire rope W, and displays the generated determination result (analysis result) of the abnormal portion on the touch panel 70.

[0084] Since the difference in distance from the wire rope W is approximately double, the magnitude of the detection signal of the component indicating the abnormal portion in the detection signal from the second differential coil 332 is approximately one-fourth of the detection signal of the component indicating the abnormal portion in the detection signal from the first differential coil 331. Therefore, even when the difference between the detection signals from the first differential coil 331 and the second differential coil 332 is obtained, the component indicating the abnormal portion is detected without being removed.

[0085] On the other hand, as in the first embodiment, it is considered that the period of change in the magnetic properties inherent to the wire rope W is at least longer than the length of the excitation coil 21 in the X direction (the direction in which the wire rope W extends). Therefore, the period of change in the magnetic properties inherent to the wire rope W is sufficiently larger than the difference between the distance d301 between the first differential coil 331 and the wire rope W and the distance d302 between the second differential coil 332 and the wire rope W, and therefore the difference between the component of the magnetic properties inherent to the wire rope W in the detection signal from the first differential coil 331 and the component of the magnetic properties inherent to the wire rope W in the detection signal from the second differential coil 332 is small. Therefore, when the difference between the detection signals from the first differential coil 331 and the second differential coil 332 is obtained, the component of the magnetic properties inherent to the wire rope W is reduced.

[0086] The other configurations of the third embodiment are the same as those of the first and second embodiments.

[0087] (Effects of the third embodiment) In the third embodiment, the following effects can be obtained.

[0088] In the third embodiment, the second differential coil 332 is wound around the wire rope W so as to cover the first differential coil 331 on the outer side of the first differential coil 331. With this configuration, the position of the first differential coil 331 relative to the wire rope W in the direction in which the wire rope W extends (X direction) can be made equal to the position of the second differential coil 332 relative to the wire rope W. This can further reduce the difference in the components of the magnetic properties inherent to the wire rope W contained in the detection signals from the first differential coil 331 and the second differential coil 332. As a result, by obtaining the difference in the detection signals, it is possible to further reduce noise components caused by the magnetic properties inherent to the wire rope W, and therefore it is possible to more accurately determine an abnormal portion of the wire rope W.

[0089] Furthermore, in the third embodiment, the second differential coil 332 is wound around the wire rope W to cover the first differential coil 331, while being spaced from the wire rope W by a distance (separation distance d302) that is approximately twice the separation distance d301 of the first differential coil 331 from the wire rope W. With this configuration, the component indicating the abnormal portion in the detection signal attenuates in proportion to the square of the distance, so that the component indicating the abnormal portion contained in the detection signal from the second differential coil 332 can be made approximately one-fourth the size of the component indicating the abnormal portion contained in the detection signal from the first differential coil 331. Therefore, in the difference between the detection signals from the first differential coil 331 and the second differential coil 332, it is possible to reduce noise components due to the inherent magnetic characteristics of the wire rope W while preventing the component indicating the abnormal portion from becoming too small.

[0090] The other effects of the third embodiment are the same as those of the first and second embodiments.

[0091] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0092] (First Modification) For example, in the second embodiment described above, the first differential coil 231 includes detector coils 231a and 231b that each cover approximately half (180 degrees) of the outer periphery of the wire rope W, and the second differential coil 232 includes detector coils 232a and 232b that each cover approximately half (180 degrees) of the outer periphery of the wire rope W. However, the present invention is not limited to this. In the present invention, as in the first differential coil 431 and second differential coil 432 according to a first modification shown in FIG. 14 , the detector coils 431a and 431b of the first differential coil 431 and the detector coils 432a and 432b of the second differential coil 432 may each be configured to cover an angle smaller than approximately half (180 degrees) of the outer periphery of the wire rope W. Note that the detector coils 431a and 431b and the detector coils 432a and 432b are a pair of saddle-shaped coils.

[0093] Specifically, as shown in Fig. 14, when the second differential coil 432 is configured to be divided along a direction (Y direction) rotated 90 degrees in the twist rotation direction of the wire rope W with respect to the direction (Z direction) in which the first differential coil 431 is divided, the detector coils 431a and 431b and the detector coils 432a and 432b may each be configured to cover a 90-degree portion of the outer circumference of the wire rope W. In this case, since the first differential coil 431 and the second differential coil 432 are arranged with a 90-degree offset from each other, it is possible to measure the entire circumference of the wire rope W by combining the detection signals of the first differential coil 431 and the second differential coil 432. Note that the detector coils 431a and 431b and the detector coils 432a and 432b may each be configured to cover a predetermined angle greater than 90 degrees of the outer circumference of the wire rope W.

[0094] (Second Modification) In the first to third embodiments, the pair of detector coils 31a (231a, 331a) and 31b (231b and 331b) in the first differential coil 31 (231, 331) and the pair of detector coils 32a (232a, 332a) and 32b (232b and 332b) in the second differential coil 32 (232, 332) are saddle-shaped coils, but the present invention is not limited to this. In the present invention, as in a first differential coil 531 and a second differential coil 532 according to a second modification shown in FIG. 15 , the pair of detector coils 531a and 531b in the first differential coil 531 and the pair of detector coils 532a and 532b in the second differential coil 532 may each be configured as a pair of flat coils forming a coil loop. In this case, too, the detection coils 531a and 531b, each of which forms a coil loop, and the detection coils 532a and 532b are combined with each other to form a coil loop that surrounds the wire rope W, and abnormal parts inside the wire rope W can be detected by the total magnetic flux method, which measures the magnetic flux inside the wire rope W.

[0095] For example, the pair of detector coils 531a and 531b of the first differential coil 531 are configured to be separable and are differentially connected to each other by a connector (not shown). The pair of detector coils 531a and 531b are combined (connected) to form a coil loop wound around the wire rope W. Specifically, the portions of each of the pair of detector coils 531a and 531b extending in a direction perpendicular to the extension direction of the wire rope W (Y direction) form a coil loop wound around the wire rope W. At this time, the pair of detector coils 531a and 531b detect magnetic characteristics in a direction perpendicular to the extension direction of the wire rope W as noise components. Therefore, a second differential coil 532 having a configuration similar to the first differential coil 531 is separately provided, and the difference between the detection signals from the first differential coil 531 and the second differential coil 532 is obtained, thereby effectively and accurately reducing the noise components.

[0096] (Other variations) Furthermore, in the second embodiment described above, an example has been shown in which the second differential coil 232 is configured to be divided along a direction (Y direction) rotated by 90 degrees in the twist rotation direction of the wire rope W with respect to the dividing direction (Z direction) of the first differential coil 231, but the present invention is not limited to this. For example, if the separation distance d201 between the first differential coil 231 and the second differential coil 232 is half the length of the twist period T of the wire rope W, the second differential coil 232 may be divided along a direction rotated by 180 degrees with respect to the dividing direction (Z direction) of the first differential coil 231.

[0097] Furthermore, in the second embodiment described above, an example has been shown in which the difference is obtained with the timing of the detection signal from the second differential coil 232 shifted compared to the timing of the detection signal from the first differential coil 231, but the present invention is not limited to this. For example, even in a case in which the second differential coil 232 is arranged so as to be divided along a direction rotated from the direction in which the first differential coil 231 is divided, the difference between the detection signal from the first differential coil 231 and the detection signal from the second differential coil 232, which are detected at approximately the same timing, may be obtained.

[0098] Furthermore, in the above-described first to third embodiments, an example was shown in which the wire rope inspection device 101 (201, 301) that detects changes in magnetic flux in the wire rope W and the processing device 102 (202) that executes the process of determining abnormal portions are configured separately, but the present invention is not limited to this. In the present invention, the detection of changes in magnetic flux in the wire rope W and the process of determining abnormal portions may be executed by a single (common) wire rope inspection device. Specifically, the wire rope inspection device may be configured to include a magnetic conditioning unit 10, a magnetic excitation unit 20, and a detection unit 30, similar to the wire rope inspection device 101 of the first embodiment, and further include a control unit that executes the process of obtaining the difference between the detection signals from the first differential coil 31 and the second differential coil 32, similar to the control unit 50 of the processing device 102 of the first embodiment.

[0099] Furthermore, in the above-described first to third embodiments, the processing device 102 (202) is an example of a tablet PC used by an inspector, but the present invention is not limited to this. For example, the processing device 102 (202) including the control unit 50 (250) that executes the process of determining an abnormal portion may be a device installed in a remote location, such as a server device. That is, the measurement results of the wire rope inspection device 101 (201, 301) may be acquired by a processing device (control unit) installed in a remote location, and the difference between the detection signals from the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) may be acquired at a position away from the elevator 103 (wire rope W) to determine an abnormal portion.

[0100] Furthermore, in the first to third embodiments, the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) have the same number of turns, but the present invention is not limited to this. For example, the number of turns of the first differential coil 31 (231, 331) and the number of turns of the second differential coil 32 (232, 332) may be different from each other. In this case, correction processing may be performed on the detection signals from the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) according to the respective numbers of turns.

[0101] Furthermore, in the above first to third embodiments, an example was shown in which the control unit 50, 250 of the processing device 102 (202, 302) calculates the difference between the detection signal from the first differential coil 31 (231, 331) and the detection signal from the second differential coil 32 (232, 332) in real time in accordance with the movement of the wire rope W, but the present invention is not limited to this. For example, the acquired detection signal from the first differential coil 31 (231, 331) and the acquired detection signal from the second differential coil 32 (232, 332) may be stored in the memory unit 60, and the difference may be calculated after the entire measurement of the wire rope W is completed.

[0102] In the first and second embodiments, the first differential coils 31, 231 and the second differential coils 32, 232 are arranged side by side so that the respective distances d101 and d102 from the wire rope W are approximately equal, but the present invention is not limited to this. For example, the distance from the wire rope W of the first differential coils 31, 231 and the distance from the wire rope W of the second differential coils 32, 232 may be different from each other.

[0103] In the first embodiment, the first differential coil 31 and the second differential coil 32 are disposed at a distance (separation distance d103) that is approximately equal to the respective separation distances d101 and d102 from the wire rope W. However, the present invention is not limited to this. For example, the separation distances d101 and d102 between the first differential coil 31 and the second differential coil 32 may be smaller than the separation distance d103 from the wire rope W. Furthermore, the separation distance d103 between the first differential coil 31 and the second differential coil 32 may be larger than the separation distances d101 and d102 from the wire rope W. For example, the separation distance d103 between the first differential coil 31 and the second differential coil 32 may be one to three times the separation distances d101 and d102 from the wire rope W.

[0104] Furthermore, in the third embodiment described above, an example was shown in which the second differential coil 332 is disposed so as to be spaced from the wire rope W by a distance (separation distance d302) that is approximately twice the distance d301 from the first differential coil 331 to the wire rope W, but the present invention is not limited to this. For example, the second differential coil 332 may be disposed so as to be spaced from the wire rope W by a distance that is smaller than approximately twice the distance d301 from the first differential coil 331 to the wire rope W. Furthermore, the second differential coil 332 may be disposed so as to be spaced from the wire rope W by a distance that is larger than approximately twice the distance d301 from the first differential coil 331 to the wire rope W.

[0105] If the separation distance between the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) is too large, the difference between the component that indicates the magnetic characteristics specific to the wire rope W contained in the detection signal from the first differential coil 31 (231, 331) and the component that indicates the magnetic characteristics specific to the wire rope W contained in the detection signal from the first differential coil 31 (231, 331) becomes large. Therefore, since it becomes impossible to reduce the component that indicates the magnetic characteristics specific to the wire rope W in the difference between the detection signals, it is better not to make the separation distance between the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) too large. Furthermore, if the distance between the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) is too small, the difference between the component indicating the abnormality contained in the detection signal from the first differential coil 31 (231, 331) and the component indicating the abnormality contained in the detection signal from the first differential coil 31 (231, 331) becomes small. Therefore, since the component indicating the abnormality in the difference between the detection signals becomes small, it is better not to make the distance between the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) too small. The distance between the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) is preferably approximately 1 to 10 times the distance between the first differential coil 31 (231, 331) and the wire rope W.

[0106] Furthermore, in the above first to third embodiments, an example has been shown in which the excitation coil 21 is wound around the wire rope W outside the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332), but the present invention is not limited to this. For example, the excitation unit 20 and the detection unit 30 (230, 330) may be arranged side by side along the direction in which the wire rope W extends. In this case, the excitation coil 21 of the excitation unit 20 may be arranged between the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332).

[0107] Furthermore, in the above-described first and second embodiments, an example was shown in which the first differential coil 31 (231) was arranged near the center position of the excitation coil 21 in the direction in which the wire rope W extends (X direction), and in the third embodiment, an example was shown in which both the first differential coil 331 and the second differential coil 332 were arranged near the center position of the excitation coil 21 in the direction in which the wire rope W extends (X direction), but the present invention is not limited to this. For example, instead of the first differential coil 31 (231), the second differential coil 32 (232) may be arranged near the center position of the excitation coil 21 in the direction in which the wire rope W extends (X direction). Furthermore, both the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) may not be arranged near the center position of the excitation coil 21 in the direction in which the wire rope W extends (X direction). Furthermore, the midpoint of the first differential coil 31 (231) and the second differential coil 32 (232) may be arranged near the center position of the exciting coil 21 in the direction in which the wire rope W extends (X direction).

[0108] Furthermore, in the above first to third embodiments, an example was shown in which moving average processing was performed on the magnetic flux waveform, which is a signal waveform based on the acquired detection signal, within a range of 10 samples (20 [ms]) before and after each sampling, but the present invention is not limited to this. The range of moving average processing may be a range other than 20 [ms]. Furthermore, moving average processing does not have to be performed when generating the magnetic flux waveform. Furthermore, a noise removal process other than moving average processing, such as low-pass filtering, may be performed to generate the magnetic flux waveform.

[0109] Furthermore, in the above first to third embodiments, examples have been shown in which the wire rope W of the elevator 103 is inspected, but the present invention is not limited to this. For example, the present invention may be configured to inspect wire ropes other than those of elevators, such as those of cranes and ropeways.

[0110] Furthermore, in the first to third embodiments, an example has been described in which the detection units 30, 230, 330 (first differential coils 31, 231, 331 and second differential coils 32, 232, 332) are moved relative to the wire rope W by moving the wire rope W of the elevator 103, but the present invention is not limited to this. For example, the detection units 30, 230, 330 (first differential coils 31, 231, 331 and second differential coils 32, 232, 332) may be configured to be moved relative to the wire rope W by moving them with respect to a fixed wire rope W. In this case, the first differential coils 31, 231, 331 and the second differential coils 32, 232, 332 may be configured to output a detection signal to the control unit 50 (250) while moving integrally with the wire rope W. Then, the control unit 50 (250) calculates the difference between the detection signals in real time according to the abnormality of the first differential coils 31, 231, 331 and the second differential coils 32, 232, 332 with respect to the wire rope W.

[0111] Furthermore, in the above first to third embodiments, an example has been shown in which the processing device 102 (202) determines whether there is an abnormal portion of the wire rope W based on the difference between the detection signals of the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332), but the present invention is not limited to this. For example, the processing device 102 (202) may be configured to perform processing to display the calculated difference between the detection signals without determining whether there is an abnormal portion.

[0112] In the first to third embodiments, the magnetic field conditioning units 10a and 10b are arranged to face each other across the wire rope W, with their north poles facing the wire rope W. However, the present invention is not limited to this. For example, the two magnetic field conditioning units 10a and 10b may be arranged so that their north and south poles face the wire rope W. The two magnetic field conditioning units 10a and 10b may be arranged so that their north and south poles face the wire rope W, rather than facing each other. In this case, the two magnetic field conditioning units 10a and 10b may face the same or different directions. The two magnetic field conditioning units 10a and 10b may be arranged so that they apply a magnetic field in a direction that is obliquely shifted from a direction parallel to the extension direction of the wire rope W. One magnetic field conditioning unit 10 may be arranged on one side of the direction intersecting the extension direction of the wire rope W. Furthermore, the magnetic flux may be detected by the detection unit 30 (230, 330) without providing the magnetic conditioning unit 10 and adjusting the magnetic field.

[0113] Furthermore, in the first to third embodiments, examples have been shown in which the magnetic field conditioning unit 10 is configured by a permanent magnet, but the present invention is not limited to this. For example, the magnetic field conditioning unit may be configured by an electromagnet.

[0114] Furthermore, in the above first to third embodiments, an example was shown in which the wire rope inspection system 100 (200, 300) was configured to detect the amount of change in magnetic flux of a single wire rope W, but the present invention is not limited to this. For example, the wire rope inspection system 100 (200, 300) may be configured to detect the amount of change in magnetic flux of multiple wire ropes W. In that case, the first differential coil 31 (231, 331) and the second differential coil 32 (232, 332) may be configured to be provided for each of the multiple wire ropes W. Note that the magnetic conditioning unit 10 and the magnetic excitation unit 20 may be provided in common for multiple wire ropes W, or multiple units may be provided to correspond to the multiple wire ropes W.

[0115] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0116] (Item 1) a magnetic excitation unit that applies a magnetic field to the wire rope; a detection unit including a first differential coil that detects a change in magnetic flux in the wire rope to which a magnetic field is applied by the excitation unit, and a second differential coil that is provided separately from the first differential coil and that detects a change in magnetic flux in the wire rope to which a magnetic field is applied by the excitation unit, and that outputs detection signals from the first differential coil and the second differential coil; a control unit that acquires a difference between the detection signal from the first differential coil and the detection signal from the second differential coil of the detection unit, Each of the first differential coil and the second differential coil has a pair of detection coils that can be separated along a direction perpendicular to the extending direction of the wire rope, A wire rope inspection system in which a pair of detector coils in each of the first differential coil and the second differential coil each form a coil loop and are combined with each other to wind around the wire rope.

[0117] (Item 2) 2. The wire rope inspection system of item 1, wherein the number of turns of the pair of detector coils in the first differential coil is approximately equal to the number of turns of the pair of detector coils in the second differential coil.

[0118] (Item 3) 3. The wire rope inspection system of claim 1, wherein the pair of sensing coils in each of the first differential coil and the second differential coil includes a pair of saddle coils.

[0119] (Item 4) The first differential coil and the second differential coil are configured to output the detection signal while moving integrally relative to the wire rope, The wire rope inspection system described in any one of items 1 to 3, wherein the control unit is configured to calculate in real time the difference between the detection signal from the first differential coil, which is moving relative to the wire rope, and the detection signal from the second differential coil, which is moving relative to the first differential coil integrally with the first differential coil, in accordance with the relative movement of the first differential coil and the second differential coil with respect to the wire rope.

[0120] (Item 5) 5. The wire rope inspection system according to any one of items 1 to 4, wherein the first differential coil and the second differential coil are arranged side by side along the extension direction of the wire rope.

[0121] (Item 6) 6. The wire rope inspection system of claim 5, wherein the first differential coil and the second differential coil are positioned so that their respective separation distances from the wire rope are approximately equal, and are spaced apart from each other by a distance approximately equal to their respective separation distances from the wire rope.

[0122] (Item 7) Item 6. The wire rope inspection system according to item 5, wherein the second differential coil is configured to be divided along a direction rotated a predetermined angle from the direction in which the first differential coil is divided toward the direction of rotation of the twist of the wire rope, depending on the ratio of the separation distance between the first differential coil and the second differential coil to the twist period of the spirally twisted wire rope.

[0123] (Item 8) 5. The wire rope inspection system according to any one of items 1 to 4, wherein the second differential coil is wound around the wire rope so as to cover the first differential coil on the outer side of the first differential coil.

[0124] (Item 9) 9. The wire rope inspection system of claim 8, wherein the second differential coil is wound around the wire rope to cover the first differential coil while being spaced from the wire rope at a distance approximately twice the distance from the wire rope of the first differential coil.

[0125] (Item 10) the excitation unit includes an excitation coil wound around the wire rope so as to cover both the first differential coil and the second differential coil, on the outer side of the first differential coil and the second differential coil; The excitation coil applies a magnetic field that oscillates along the extension direction of the wire rope when an alternating current is passed through the excitation coil, A wire rope inspection system as described in any one of items 1 to 9, wherein at least one of the first differential coil and the second differential coil is arranged near the center position of the excitation coil in the direction in which the wire rope extends. [Explanation of symbols]

[0126] 20 Excitation section 21 Excitation coil 30, 230, 330 Detector 31, 231, 331, 431, 531 First differential coil 31a, 31b, 32a, 32b, 231a, 231b, 232a, 232b, 331a, 331b, 332a, 332b, 431a, 431b, 432a, 432b, 531a, 531b, 532a, 532b Detector coil 32, 232, 332, 432, 532 Second differential coil 50, 250 control section 100, 200, 300 Wire Rope Inspection Systems

Claims

1. a magnetic excitation unit that applies a magnetic field to the wire rope; a detection unit including a first differential coil that detects a change in magnetic flux in the wire rope to which a magnetic field is applied by the excitation unit, and a second differential coil that is provided separately from the first differential coil and that detects a change in magnetic flux in the wire rope to which a magnetic field is applied by the excitation unit, and that outputs detection signals from the first differential coil and the second differential coil; a control unit that acquires a difference between the detection signal from the first differential coil and the detection signal from the second differential coil of the detection unit, Each of the first differential coil and the second differential coil has a pair of detection coils that can be separated along a direction perpendicular to the extending direction of the wire rope, A wire rope inspection system in which the pair of detector coils in each of the first differential coil and the second differential coil each form a coil loop and are combined with each other to wind around the wire rope.

2. 2. The wire rope inspection system of claim 1, wherein the number of turns of the pair of detector coils in the first differential coil is approximately equal to the number of turns of the pair of detector coils in the second differential coil.

3. 3. The wire rope inspection system of claim 1, wherein the pair of sensing coils in each of the first differential coil and the second differential coil comprises a pair of saddle coils.

4. the first differential coil and the second differential coil are configured to output the detection signal while moving integrally relative to the wire rope, The wire rope inspection system of any one of claims 1 to 3, wherein the control unit is configured to calculate in real time the difference between the detection signal from the first differential coil moving relative to the wire rope and the detection signal from the second differential coil moving relative to the first differential coil integrally with the first differential coil in accordance with the relative movement of the first differential coil and the second differential coil relative to the wire rope.

5. The wire rope inspection system according to any one of claims 1 to 4, wherein the first differential coil and the second differential coil are arranged side by side along the extension direction of the wire rope.

6. 6. The wire rope inspection system of claim 5, wherein the first differential coil and the second differential coil are positioned so that their respective distances from the wire rope are approximately equal, and are positioned so that they are spaced apart from each other by a distance approximately equal to their respective distances from the wire rope.

7. 6. The wire rope inspection system according to claim 5, wherein the second differential coil is configured to be divided along a direction rotated a predetermined angle from the direction in which the first differential coil is divided toward the rotation direction of the twist of the wire rope, depending on the ratio of the separation distance between the first differential coil and the second differential coil to the twist period of the spirally twisted wire rope.

8. The wire rope inspection system according to any one of claims 1 to 4, wherein the second differential coil is wound around the wire rope so as to cover the first differential coil outside the first differential coil.

9. 9. The wire rope inspection system of claim 8, wherein the second differential coil is wound around the wire rope to cover the first differential coil while being spaced from the wire rope at a distance approximately twice the distance from the wire rope of the first differential coil.

10. the excitation unit includes an excitation coil wound around the wire rope so as to cover both the first differential coil and the second differential coil, on an outer side of the first differential coil and the second differential coil; The excitation coil applies a magnetic field that oscillates along the extension direction of the wire rope when an alternating current is passed through the excitation coil, A wire rope inspection system as described in any one of claims 1 to 9, wherein at least one of the first differential coil and the second differential coil is arranged near the center position of the excitation coil in the direction in which the wire rope extends.

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