JP2013195270A - Flaw detector for wire rope and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flaw detector for monitoring presence/absence of a noise signal caused by small vibration of a wire rope and for, when the noise signal is included in a detected signal, masking damage detection of the wire rope by digital filter delay time, and to provide a control method of the flaw detector.SOLUTION: The wire rope flaw detector for detecting damage of a wire rope includes: a magnetizer including a pair of permanent magnets having reversed magnetic poles, arranged at both end parts of a ferromagnetic body; a coil for detecting a leakage magnetic flux of the wire rope magnetized by the magnetizer; and a controller 2 for signal processing a detected signal from the coil. The controller 2 includes: a processing part 17 for performing filter processing for delaying the detected signal when the detected signal includes a noise signal; and a determination part 18 for determining presence/absence of the damage of the wire rope on the basis of output of the processing part 17.

Description

  The present invention relates to a wire rope flaw detector and a control method thereof by a leakage magnetic flux flaw detection method, and more particularly, to a flaw detector and a control method thereof for displaying a damage level in downsizing.

  Conventionally, the following techniques are disclosed in a wire rope flaw detector using a leakage magnetic flux flaw detection method.

  The flaw detection device of the invention disclosed in Japanese Patent Application Laid-Open No. Hei 7-198684 (Patent Document 1) processes a detection signal and a magnetizer for magnetizing a wire rope, a probe with a built-in coil for detecting a damaged portion. It consists of a controller. The wire rope is magnetized by an electromagnet provided inside the magnetizer, and magnetic flux is passed in the longitudinal direction of the wire rope. At this time, if the wire rope is broken or locally worn, a leakage magnetic flux is generated at the damaged portion. When the wire rope moves and the leakage flux is interlinked with the probe coil built in the probe, a minute voltage is generated in the probe coil. This voltage is detected by an electronic circuit of the controller, subjected to signal processing such as detection and amplification, and output as a flaw detection signal.

  The signal waveform of the new rope without disconnection is that of a noise signal having a small absolute value, and the signal waveform of the rope including the disconnection is detected as a signal waveform that protrudes greatly corresponding to the disconnection location. Since this flaw detection apparatus is inconvenient to carry because of its weight and size, it is reduced in weight by using a permanent magnet and a strip-shaped ferromagnetic plate as a magnetizer, and integrated with the probe. This was integrated with the controller and separated.

  Next, in the flaw detection apparatus control method disclosed in Japanese Patent Application Laid-Open No. 2006-177770 (Patent Document 2), first, a signal detected by the sensor is taken into the wrinkle determination apparatus according to a command from the control unit. Here, as described above, the signal detected by the sensor is amplified by the amplifier and A / D converted by the A / D converter. The captured signal is stored in the storage unit. Whether or not to inspect the presence or absence of dents is input by the input means by the operator. If the presence or absence of dents is not inspected, the control proceeds to a process for inspecting for the presence of cracks having a wide opening width by the control unit. When the presence / absence of a dent flaw is inspected, the flaw detection frequency of the dent flaw is input by the operator by the input means, and the flaw detection frequency is set.

  Based on this flaw detection frequency, the detection signal stored in the storage unit is corrected by the processing unit. The processing unit is the same as the signal when the detection signal is passed through a high-pass filter having a lower limit frequency of the flaw detection frequency as a high-pass filter setting value and passed through a low-pass filter having the upper limit frequency of the flaw detection frequency as a low-pass filter setting value. Filter the signal to correct the detection signal. The signal corrected by the processing unit is stored in the storage unit. Based on the stored signal, the determination unit determines the presence or absence of dents. This determination is made based on whether or not the intensity of the signal obtained by subtracting the noise signal from the heel signal is equal to or greater than a threshold value.

Japanese Unexamined Patent Publication No. 7-198684 JP 2006-177770 A

  The flaw detection device of the invention disclosed in Japanese Patent Application Laid-Open No. 7-198684 (Patent Document 1) displays damage with a digital level meter in order to provide a device that is small and easy to carry. In this case, when the measurement is started by moving the wire rope in the tensioning direction, the wire rope slightly vibrates and the noise signal increases. It is conceivable that the flaw detection apparatus incorporating the increase boundary of the noise signal detects an unnecessary damage peak depending on the rising speed of the noise signal by digital filter processing.

  In the method of controlling a flaw detection apparatus disclosed in Japanese Patent Application Laid-Open No. 2006-177770 (Patent Document 2), when masking is performed based on the presence or absence of a noise signal so as not to detect an unnecessary peak, a signal within a filter delay time is used. It is conceivable that the effect of the rise of the signal due to noise remains in the processing and an unnecessary peak appears.

  Therefore, in order to solve the above problem, an object of an embodiment of the present invention is to monitor the presence or absence of a noise signal due to minute vibrations of the wire rope. An object of the present invention is to provide a flaw detection apparatus that masks damage detection by a digital filter delay time and a control method thereof.

  According to one embodiment of the present invention, there is provided a wire rope flaw detector for detecting damage to a wire rope, wherein a magnetizer having a pair of permanent magnets having magnetic poles reversed at both ends of a ferromagnetic material, and a magnetizer A coil for detecting the leakage flux of the wire rope magnetized by the controller, and a controller for signal processing the detection signal from the coil, the controller delays the detection signal when the detection signal has a noise signal A processing unit that performs filtering, and a determination unit that determines whether or not the wire rope is damaged based on an output of the processing unit.

  Preferably, the determination unit, when the detection signal output from the processing unit does not have a noise signal, and the detection signal after a certain time has elapsed from the time when it is determined that the detection signal does not have a noise signal, It is determined that the coil is disconnected.

  More preferably, the processing unit includes a first multiplier that receives the detection signal, a delay element that receives the detection signal, a second multiplier that receives an output of the delay element, an output of the first multiplier, and a second And an adder for adding the outputs of the multipliers, and the processing unit outputs a delayed detection signal.

  More preferably, the controller further includes a display unit that displays a detection result of the wire rope damage based on the detection signal, and the controller controls the display unit to change the display level according to the detection result. To do.

  Preferably, the controller further includes a storage unit that stores the detection result, and the controller obtains a maximum value of the detection result stored in the storage unit every predetermined time and controls the display unit to display the maximum value. .

  According to an embodiment of the present invention, it is possible to eliminate erroneous detection due to unnecessary peak detection by capturing a signal at a boundary where a noise signal increases due to minute vibration of a wire rope, and mask only the digital filter delay time. Thus, the detection of the damage peak can be started with the minimum mask time.

1 is a perspective view of a wire rope flaw detector according to a first embodiment of the present invention. It is a figure for demonstrating the principle in which the wire rope flaw detector based on the 1st Embodiment of this invention detects the damaged part of a wire rope. It is the perspective view of the wire rope flaw detector which looked at FIG. 1 from the other side. It is the figure which showed the example of the lighting state of the level meter 4 which displays a damage level. It is the block diagram in which the structure of the damage determination apparatus 11 used for the wire rope flaw detector based on the 1st Embodiment of this invention was shown. FIG. 6 is a diagram illustrating a configuration of digital filter processing of a processing unit 17. It is a figure which shows the measurement result by the wire rope flaw detector of this Embodiment. It is a figure which shows the measurement result when not performing a digital filter process as a reference example. It is a flowchart which shows the inspection method of the wire rope flaw detector based on the 1st Embodiment of this invention. It is a flowchart which shows the coil disconnection detection method of the probe of the wire rope flaw detector based on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, in each following embodiment, the same code | symbol is attached | subjected about the same component.

[First Embodiment]
FIG. 1 is a perspective view of a wire rope flaw detector according to a first embodiment of the present invention. Referring to FIG. 1, this wire rope flaw detector includes a magnet with a pair of permanent magnets having magnetic poles reversed at both ends of a ferromagnetic material and a probe with a built-in coil for detecting leakage magnetic flux. An integrated probe built-in magnetizer 1 and a controller 2 that detects a signal from the probe built-in magnetizer 1 are provided.

  The probe built-in magnetizer 1 is connected so as to be integrated with a controller 2 that performs signal processing on a detection signal from the probe. Provided is a small wire rope flaw detector that is easy to carry by integrating. The probe built-in magnetizer 1 has a smooth curve that follows the wire rope, and allows a magnetic flux necessary for flaw detection to pass through, and at the same time, detects a leakage magnetic flux by a coil provided inside.

  Fixing fittings 3 for fixing the wire rope flaw detector are further provided on the upper and lower portions of the wire rope flaw detector.

  FIG. 2 is a diagram for explaining the principle by which the wire rope flaw detector according to the first embodiment of the present invention detects a damaged portion of the wire rope.

  Referring to FIG. 2, the wire rope a is strongly magnetized by the permanent magnet 1 a provided in the probe built-in magnetizer 1 and the magnetic flux d is passed in the longitudinal direction of the wire rope a. At this time, if the wire rope a is broken or locally worn, a leakage magnetic flux c is generated in the damaged portion b. When the wire rope a moves and the coil 1b built in the probe and the leakage magnetic flux c are linked, a minute voltage is generated between the terminals 1c-1d. This voltage is detected by an electronic circuit of the controller 2, and signal processing such as detection and amplification is performed and output as a flaw detection signal. In the case of the probe built-in magnetizer 1, the coil 1b is preferably provided between the wire rope a and the permanent magnet 1a.

  FIG. 3 is a perspective view of the wire rope flaw detector as viewed from the opposite side of FIG. Referring to FIG. 3, the controller 2 has a level meter 4 for displaying the level of damage to the wire rope, a power switch 5 for turning on the power of the wire rope flaw detector, and the wire rope speed at the time of wire rope flaw detection. And a setting switch 6 for setting.

  FIG. 4 is a diagram showing an example of the lighting state of the level meter 4 that displays the damage level. Referring to FIG. 4, the LED 7 of the level meter 4 can be displayed for each level of abnormality, strong warning, weak warning, and normal range according to the damage state. Further, after the start of measurement, the damage level is peak-held. By adopting such a configuration, the operator can perform appropriate processing without missing the damage detection. In addition, the display method of LED7 may display two or more LED7 according to the magnitude | size of a damage level. Further, a digital display or a display using a pattern may be used without using the LED 7.

  When flaw detection measurement is started, the power switch 5 of the controller 2 is operated to turn on the power, and the wire rope speed setting switch 6 necessary for the filter processing is operated. The controller 2 detects a minute voltage due to the leakage magnetic flux detected from the probe, and performs a filter process for removing a noise signal on the detection signal from the probe to detect a damage level. This is because the detection signal from the probe includes a noise signal due to the vibration of the wire rope, and is performed to extract a damage signal in the noise signal.

  FIG. 5 is a block diagram showing the structure of the damage determination device 11 used in the wire rope flaw detector according to the first embodiment of the present invention. Referring to FIG. 5, the controller 2 includes a damage determination device 11 and an output unit 19.

  Here, the damage determination apparatus 11 includes a control unit 12, an amplifier 14, an AD conversion unit 15, a storage unit 16, a processing unit 17, and a determination unit 18. The probe built-in magnetizer 1 detects the leakage magnetic flux, and the probe signal output corresponding to the magnetic flux is amplified by the amplifier 14 and then sent to the AD converter 15.

  Further, the signal sent to the AD conversion unit 15 is AD converted, and the digital value is stored in the storage unit 16. The digital value stored in the storage unit 16 is digitally filtered by the processing unit 17, and the determination unit 18 determines whether there is damage. The control unit 12 controls the AD conversion unit 15, the storage unit 16, the processing unit 17, and the determination unit 18 in order to perform the above-described operation.

  FIG. 6 is a diagram showing the configuration of the digital filter processing of the processing unit 17. Referring to FIG. 6, processing unit 17 includes delay elements 41 </ b> A to 41 </ b> N, filter coefficient multipliers 42 and 42 </ b> A to 42 </ b> N, and an adder 43. The delay elements 41A to 41N are also collectively referred to as the delay element 41.

  The processing unit 17 receives the output signal from the storage unit 16 as an input signal, is processed by the product-sum operation of the delay element 41 of the processing unit 17, the filter coefficient multiplier 42, and the adder 43, and is output to the determination unit 18. To do.

  Specifically, the delay element 41A receives an output from the storage unit as an input signal. The next-stage delay element 41B receives the output of the delay element 41A. Thus, the delay element at the next stage receives the output of the immediately preceding delay element.

  On the other hand, the voltages of the input node of delay element 41 and the connection node between the delay elements are applied to corresponding filter coefficient multipliers 42 and 42A to 42N, respectively. The outputs of the filter coefficient multipliers 42 and 42 </ b> A to 42 </ b> N are given to the adder 43.

  In particular, since there are N delay elements 41, the output signal of the delay element 41N is affected by the N-th previous input signal. In other words, since there are a plurality of delay elements 41 inside, a delay time is generated by the number of delay elements 41. Therefore, by using this, the influence of the rising portion of the input signal can be eliminated by not determining the output signal within the delay time of N delay elements.

  FIG. 7 is a diagram showing a measurement result obtained by the wire rope flaw detector according to the present embodiment. FIG. 8 is a diagram showing a measurement result by a conventional wire rope flaw detector as a reference example. In the conventional wire rope flaw detector shown in FIG. 8, a noise signal may be generated when the vibration is started / stopped by starting / stopping the wire rope operation before and after the start of measurement or before / after the measurement. In particular, it is conceivable that an unnecessary peak is generated when the rising speed of the noise signal is within the filter processing pass frequency.

  Specifically, in the waveform of the reference example, an unnecessary peak P1 appears when vibration starts when the wire rope starts to move, while an unnecessary peak appears when vibration stops when the wire rope stops. P2 appears.

  On the other hand, referring to FIG. 7, a desired measurement result can be acquired without occurrence of unnecessary peaks such as P1 and P2 before and after the start of measurement (time t1) and before and after the completion of measurement (time t2).

  Therefore, by adopting the configuration of the wire rope flaw detector according to the present embodiment, peak noise can be removed without causing unnecessary noise peaks as in the reference example.

  FIG. 9 is a flowchart showing an inspection method of the wire rope flaw detector according to the first embodiment of the present invention. Among the operations of the flowchart described below, the processing performed by the AD conversion unit 15, the storage unit 16, the processing unit 17, and the determination unit 18 is performed by the control unit 12 using the AD conversion unit 15, the storage unit 16, the processing unit 17, and the determination unit 18. Is controlled and processed. Referring to FIGS. 5 and 9, when power is turned on to the wire rope flaw detector according to the first embodiment, a signal detected by the probe provided in the probe built-in magnetizer 1 according to a command from the control unit 12 is generated. It is taken into the wire rope flaw detector (step 21). Here, the signal detected by the probe provided in the probe built-in magnetizer 1 is amplified by the amplifier 14 and AD-converted by the AD converter 15. The captured signal is stored in the storage unit 16 as a digital value (step 22).

  Next, the processing unit 17 reads the detection signal from the storage unit 16, determines whether the detection signal includes a noise signal (step 23), and determines that the noise signal is not included in the detection signal. In this case, the process returns to step 21 again (step 23; NO). This makes it possible to know whether or not the wire rope to be inspected is moving in the vertical direction of the probe built-in magnetizer 1 of the wire rope flaw detector by detecting the presence or absence of a noise signal, and performing flaw detection when the wire rope is not moving. There is nothing.

  On the other hand, when the processing unit 17 determines that the noise signal is included in the detection signal (step 23; YES), the processing unit 17 determines whether or not the delay time resulting from the digital filter processing has elapsed next. Judgment is made (step 24).

  Here, when the processing unit 17 determines that the delay time resulting from the digital filter processing has elapsed (step 24; YES), the processing unit 17 detects the influence of the noise signal generation boundary caused by the digital filter processing. The signal is output to the determination unit 18 (step 25). By the processing in step 25, unnecessary peak display on the level meter that can be visually recognized by the operator can be eliminated. If the control unit 12 determines that the delay time resulting from the digital filter process has not elapsed (step 24; NO), the process returns to step 21.

  The determination unit 18 determines the presence or absence of damage from the detection signal from which noise has been removed (step 26). Then, the determination unit 18 determines whether or not the wire cable is damaged from the detection signal from which the noise has been removed, gives a damage level signal (not shown) according to the determination result to the output unit 19, and responds to the damage level signal. Then, the LED 7 is turned on, and the process proceeds to the next step 28.

  In step 28, the control unit 12 holds the peak (maximum value) of the damage level (peak hold) after the end of the measurement, and the processes from steps 21 to 28 are repeated again. The damage level peak of the entire wire rope may be held as the damage level peak, or the damage level peak for each measurement may be held.

  Such a configuration and operation control can eliminate false detection due to unnecessary peak detection by capturing a signal at the boundary where the noise signal increases due to minute vibration of the wire rope, and only the digital filter delay time is saved. By masking, a damage peak can be detected with a minimum mask time.

[Second Embodiment]
The configuration of the wire rope flaw detector according to the second embodiment is similar to the configuration of the wire rope flaw detector according to the first embodiment, and therefore description thereof will not be repeated here. Operation control of the wire rope flaw detector according to the second embodiment will be described below.

  FIG. 10 is a flowchart showing a coil breakage detection method of the probe of the wire rope flaw detector according to the second embodiment of the present invention. Among the operations of the flowchart described below, the processing performed by the AD conversion unit 15, the storage unit 16, the processing unit 17, and the determination unit 18 is performed by the control unit 12 using the AD conversion unit 15, the storage unit 16, the processing unit 17, and the determination unit 18. Is controlled and processed.

  Referring to FIGS. 5 and 10, when power is turned on to the wire rope flaw detector according to the second embodiment, the processes of steps 21 and 22 described in FIG. 9 are performed. When the process of step 22 is completed, the processing unit 17 reads the detection signal from the storage unit 16 and determines whether or not a noise signal is included in the detection signal (step 23).

  If the processing unit 17 determines that the noise signal is not included in the detection signal, the processing proceeds to step 31 (step 23; NO). On the other hand, when the processing unit 17 determines that the noise signal is included in the detection signal, the subsequent processing is performed in steps S25 to S28 described in FIG. 6 (step 23; YES).

  When the detection signal does not have a noise signal, the control unit 12 determines whether or not the detection signal does not have a noise signal even after a predetermined time has elapsed (step 31). Here, when the control unit 12 determines that the detection signal does not have a noise signal even after a predetermined time has elapsed, the process proceeds to step 32 (step 31; YES). On the other hand, when the control unit 12 determines that the detection signal has a noise signal even after a predetermined time has elapsed, the process returns to step 21 (step 31; NO). This fixed time can be arbitrarily set. For example, the time required for one measurement by the wire rope flaw detector may be set.

  When the processing unit 17 determines that the detection signal does not include a noise signal even after a predetermined time has elapsed, it is assumed that the coil is disconnected, the coil is disconnected to the measurer, and the wire rope flaw detector is Abnormality is displayed using the LED 7 (step 32). The abnormality display can be notified to the measurer by the display of the level meter 4 such as blinking one of the LEDs in FIG. By confirming the display, the measurer can easily detect the abnormality of the wire rope flaw detector.

  Note that steps 21 to 22 and 25 to 28 of the second embodiment are the same as the steps of the first embodiment, and therefore description thereof will not be repeated here.

  By performing this kind of operation control, when the damage detection is displayed with a level meter, that is, when it can be detected normally while observing the waveform, it is possible to detect the disconnection of the coil depending on the presence or absence of a noise signal. By detecting it, it is possible to know the abnormality of the wire rope flaw detector itself.

Finally, the first and second embodiments will be summarized with reference to the drawings and the like.
The wire rope flaw detector according to the first embodiment is a wire rope flaw detector that detects damage to the wire rope a as shown in FIGS. 1, 2, and 5, and includes magnetic poles at both ends of the ferromagnetic material. A magnetizer 1 in which a pair of permanent magnets having a reversed shape is arranged, a coil 1b for detecting a leakage magnetic flux c of a wire rope a magnetized by the magnetizer 1, and a detection signal from the coil 1b are signal-processed. The controller 2 includes a processing unit 17 that performs a filtering process for delaying the detection signal when the detection signal has a noise signal, and whether or not the wire rope a is damaged based on the output of the processing unit 17. And a determination unit 18 for determination.

  The wire rope flaw detector according to the second embodiment has the same configuration as that of the wire rope flaw detector according to the first embodiment as shown in FIGS. 5 and 10. Preferably, the determination unit 18 is a processing unit. When the detection signal output from 17 does not have a noise signal and the detection signal does not have a noise signal after a certain time has elapsed since it is determined that the detection signal does not have a noise signal, it is determined that the coil 1b is disconnected.

  More preferably, as shown in FIG. 6, the processing unit 17 includes a first multiplier 42 that receives the detection signal, a delay element 41A that receives the detection signal, and a second multiplier 42A that receives the output of the delay element 41A. And an adder 43 that adds the output of the first multiplier 42 and the output of the second multiplier 42A, and the processing unit 17 outputs a delayed detection signal.

  More preferably, as shown in FIGS. 4, 9, and 10, the controller 2 further includes a display unit that displays a detection result of the damage of the wire rope a based on the detection signal. The unit controls the display level to change according to the detection result.

  Preferably, as shown in FIG. 4 and FIG. 9, the controller 2 further includes a storage unit that stores the detection result, and the controller 2 sets the maximum value of the detection result stored in the storage unit every predetermined time. Obtain and control to display on the display unit.

  By adopting such a configuration, by detecting the start and end of measurement based on the presence or absence of a noise signal, it is possible to prevent detection of unnecessary peaks caused by digital filter processing at the start and end of the noise signal. Can do.

  In addition, by adopting such a configuration, when displaying damage detection with a level meter, that is, when it is not possible to check whether the detection is normal or while looking at the waveform, the disconnection of the coil is checked for the presence or absence of a noise signal. It is possible to know the abnormality of the wire rope flaw detector itself.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Magnetizer, 1a Permanent magnet, 1b Coil, 1c, 1d terminal, 2 Controller, 3 Fixing bracket, 4 Level meter, 5 Power switch, 6 Setting switch, 11 Damage determination apparatus, 12 Control part, 14 Amplifier, 15 AD Conversion unit, 16 storage unit, 17 processing unit, 18 determination unit, 19 output unit, 41, 41A to 41N delay element, 42 filter coefficient multiplier, 43 adder, a wire rope, b damaged unit, c leakage flux, d Magnetic flux.

Claims (5)

A wire rope flaw detector for detecting wire rope damage,
A magnetizer in which a pair of permanent magnets having magnetic poles reversed at both ends of a ferromagnetic material are disposed;
A coil for detecting leakage magnetic flux of the wire rope magnetized by the magnetizer;
A controller for processing a detection signal from the coil;
The controller is
A processing unit that delays the detection signal when the detection signal has a noise signal;
A wire rope flaw detector comprising: a determination unit that determines whether the wire rope is damaged based on an output of the processing unit. The determination unit
When the detection signal output from the processing unit does not have the noise signal, and the detection signal after a predetermined time has passed since it is determined that the detection signal does not have the noise signal, the coil The wire rope flaw detector according to claim 1, wherein the wire rope flaw detector is determined to be a broken wire. The processor is
A first multiplier for receiving the detection signal;
A delay element for receiving the detection signal;
A second multiplier receiving the output of the delay element;
An adder for adding the output of the first multiplier and the output of the second multiplier;
The wire rope flaw detector according to claim 1, wherein the processing unit outputs the delayed detection signal. The controller is
Based on the detection signal, further comprising a display unit for displaying a detection result of damage of the wire rope,
The wire rope flaw detector according to claim 1 or 2, wherein the controller controls the display unit to change a display level according to the detection result. The controller is
A storage unit for storing the detection result;
The wire rope flaw detector according to claim 4, wherein the controller acquires the maximum value of the detection result stored in the storage unit every predetermined time and controls the display unit to display the maximum value.

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