JP2019113453A - Gate pin inspection device and method for inspecting gate pin - Google Patents

Abstract

To provide an inspection device for easily and inexpensively evaluating the frictional force of a gate pin.SOLUTION: A gate pin inspection device 10 for inspecting a gate pin includes: an AE sensor 11 attached to the gate pin; a waveform acquisition unit 12 for acquiring an AE waveform from the AE sensor 11; an evaluation unit 13 for evaluating the frictional force of the gate pin, using a predetermined DA value obtained on the basis of the waveform acquired by the waveform acquisition unit 12; and an output unit 14 for outputting the result of evaluation by the evaluation unit 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gate pin inspection apparatus and inspection method, and more particularly to a gate pin inspection apparatus and inspection method using an AE (Acoustic Emissions) waveform.

  Conventionally, the frictional force of a radial gate support member (hereinafter referred to as "gate pin") is to be inspected in the technical standard of structural design (for example, water gate iron technical standard). FIG. 11 is a diagram showing an entire configuration of the radial gate 100. As shown in FIG. Referring to FIG. 11, the radial gate 100 is provided in a water gate or the like that closes the upstream and downstream of the river, and the door 103 and the leg 102 connecting the door 103 and the rotating pin (support) 101 including. A winding wire (not shown) is connected to the door 103, and the door 103 is rotated about the rotation pin 101 by winding the wire. However, since the door 103 is normally closed, the friction of the rotating pin 101 increases over time, and the movement becomes worse. As a result, the resistance moment of the legs 102 increases during the opening and closing operation, and the legs 102 may buckle, leading to the collapse of the entire radial gate 100. Therefore, it is necessary to periodically check the frictional force of the rotating pin 101. In order to evaluate this frictional force, it is necessary to apply a strain gauge to the leg and measure the resistance moment directly. Moreover, since the friction of the bearing changes over time, it is necessary to monitor the change periodically.

  On the other hand, an apparatus for analyzing the frictional wear phenomenon of a friction member using an AE sensor is disclosed, for example, in Japanese Patent Application Laid-Open No. 2015-25713 (Patent Document 1). According to the same publication, the friction and wear phenomenon analysis device comprises a pressing device for bringing the friction member into frictional contact with the rotating member and a biasing member for bringing the AE sensor into contact with the friction member 2 in a separate system. There is a description that contact is surely performed to detect AE generated in the friction member with high sensitivity.

JP, 2015-25713, A

  In order to inspect the friction force of the conventional gate pin part, there is a problem that labor cost, scaffolding cost, etc. occur and it takes time and cost. On the other hand, conventionally, there has been no idea of evaluating a gate pin using an AE sensor.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has its object to provide a gate pin inspection apparatus and method using an AE waveform inexpensively and easily.

  An inspection apparatus for a gate pin according to the present invention includes an AE sensor attached to the gate pin, a waveform acquisition unit for acquiring an AE waveform from the AE sensor, and a predetermined DA value acquired based on the waveform acquired by the waveform acquisition unit. The evaluation part which evaluates the frictional force of a gate pin using, and the output part which outputs the evaluation result of an evaluation part are included.

  Preferably, the evaluation unit evaluates the frictional force of the gate pin using the RMS value of the waveform acquired by the waveform acquisition unit.

  More preferably, the evaluation unit identifies the frictional force of the gate pin into a plurality of regions using the AE waveform acquired by the waveform acquisition unit and the RMS value of the AE waveform.

  In another aspect of the present invention, a method of inspecting a gate pin includes the steps of acquiring an AE waveform from an AE sensor attached to the gate pin, and evaluating the frictional force of the gate pin using a predetermined DA value based on the acquired waveform. And outputting an evaluation result.

  According to the present invention, the AE waveform resulting from the friction is acquired, and based on that, the evaluation value is obtained to evaluate the bearing portion. As in the prior art, there is no need to provide a hand or foothold. As a result, it is possible to provide a gate pin inspection apparatus and inspection method that can inspect a gate pin inexpensively and easily.

It is a block diagram which shows the whole structure of a gate pin test | inspection apparatus. It is a figure explaining an DA value which an evaluation part uses for evaluation. It is a figure which shows the outline | summary of measurement. It is a figure which shows a friction coefficient measurement result. It is a figure which shows the example of a setting of a danger area | region. It is a figure which shows the identification index of friction coefficient estimation. It is a figure which shows the identification index of friction coefficient estimation. It is a flowchart which shows the process which a control part performs. It is a figure which shows the result of having applied the identification index to the corrosion flat plate. It is a figure which shows the result of having applied the identification index with respect to field measurement data. It is a figure showing a radial gate.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an entire configuration of a gate pin inspection apparatus according to an embodiment of the present invention. Referring to FIG. 1, the gate pin inspection apparatus 10 includes an AE sensor 15 attached to the gate pin to detect AE data, a waveform acquiring unit 12 acquiring AE waveform data from the AE sensor 15, and a waveform acquiring unit 12 Evaluation unit 13 that evaluates the degree of friction from the acquired AE waveform, output unit 14 that outputs the evaluation result of evaluation unit 13, control unit that controls waveform acquisition unit 12, evaluation unit 13, and output unit 14 (CPU And).

  Next, the evaluation content of the evaluation unit 13 will be described. FIG. 2 is a diagram for explaining the AE waveform acquired by the waveform acquisition unit 12. Referring to FIG. 2, the X-axis represents time (ms) and the Y-axis represents amplitude (voltage V). Here, the AE waveform is a waveform that attenuates after the amplitude gradually increases and reaches a certain maximum amplitude as shown in the drawing. When an AE waveform is input, the time to first exceed a predetermined threshold and reach the maximum amplitude value is called signal rise time.

  Here, the amplitude value gives information corresponding to the magnitude of the vibration given to the transducer by the event that has caused the AE, that is, the seismic intensity of the earthquake. By applying statistical processing, an amplitude distribution is obtained, and relative energy levels can be compared between generated AE events. Using this, it may be possible to identify different AE generation mechanisms. In addition, in the amplitude distribution, the continuous occurrence of high-amplitude events found in the area outside the linear portion may correspond to the growth of harmful defects. Thus, the maximum amplitude value is an important measure to know the risk of AE events.

  The time until the AE waveform first exceeds the threshold and passes through the maximum amplitude and falls below the threshold is referred to as the signal duration. That is, the signal duration is defined as the time from the first threshold crossing to the last threshold crossing at the time of signal input, that is, the touch time of one hit. By combining this value with the signal rise time and the maximum amplitude value, it is possible to obtain information on the rough waveform of the input signal. Based on this information, it may be possible to identify different AE sources.

  In this embodiment, a predetermined DA value is used. Here, the DA value is obtained by the following equation.

DA value = (signal duration−rise time) / maximum amplitude value This value represents the reciprocal of the slope from when the waveform shows the maximum amplitude value to when it falls below the threshold value. That is, this value can be used to evaluate the degree to which the AE waveform continuously occurs.

  In this embodiment, it is preferable to use not only the DA value but also the RMS value of the AE waveform.

  Here, an RMS value (Root Mean Square Value) (rms voltage) is used to know a rough change in AE activity. Since the time constant is as large as about 100 to 200 ms, it can not cope with an early phenomenon as in the sudden AE, but it is suitable when a continuous signal is generated, such as metal deformation or leak detection. The RMS value is obtained by the following equation. Td in the following equation is a period, and x (t) is a function system of the AE waveform.

  That is, in this embodiment, by using the DA value as a parameter for measuring the waveform continuity and further using the RMS to evaluate the signal strength of the continuous AE, noise or a signal that is not generated frequently It distinguishes.

  Next, a specific data acquisition method performed in this embodiment will be described. AE structures were measured by moving four types of rectangular solid structures having different weights and contact surfaces on the grinder-treated S50C flat plate.

  The outline of the measurement method is shown in FIG. 3 as a steel material measurement item. The movable body 21 is installed at a position 100 mm from the center of the right end of the steel material 20 and is moved as a movement range 22 by a distance of 400 mm. The moving time was fixed at 8 seconds and the moving speed was constant. Acoustic waves generated by friction and wear that occur during movement are acquired as signals by an AE sensor. The AE sensor was installed on the back surface of the steel material 20 so as to sandwich the movement start point of the moving body 21 (indicated by circular dotted lines 23 and 23b in the drawing).

  Although it is measurement data, the elastic wave at the time of 4 types of moving bodies moving the distance of 400 mm is used. In addition, the data was acquired by moving a moving object six times in total and making a waveform exceeding 40 dB one hit. The data used for the result is only the waveform that was generated when the mobile started moving by adding the waveform with AE energy of 0 and AE count value of 1 as noise. In this measurement, the data generated at the start of movement is the maximum value of the frictional force measured by the force gauge, and the data generated at that moment is measured for 0.5 s. The AE was used as the AE at the time of friction breakage, and the parameter analysis was performed.

  The calculation process of the coefficient of friction is shown below. The moving body 21 is moved by a force gauge fixed to the carriage. Measure the time history of the friction force generated at that time. The coefficient of friction was calculated from the maximum frictional force (static frictional force). The coefficient of friction was calculated using Coulomb-Amonton's law F / P (the value obtained by dividing the frictional force F by the vertical load P). The vertical load was determined from the mass of each moving body 21. The results of the coefficient of friction are shown in FIG.

  Next, measurement results will be described. The DA value and the RMS value of AE of each moving body 21 are shown separately for the coefficient of friction. The coefficient of friction is shown in FIG. The plot is changed according to the coefficient of friction. □ indicates the friction coefficient of 0.17, Δ indicates the friction coefficient of 0.27, × indicates the friction coefficient of 0.2, and ◇ indicates the friction coefficient of 0.27. Show.

  AE generated by a moving body with a friction coefficient of 0.27 shows a high value with a DA value of 2000 or more and an RMS value of 0.003 or more compared with AE generated with a moving body with a friction coefficient of 0.2 or less It can be confirmed that the waveform of a strong signal is measured continuously. As compared with the case where the coefficient of friction is high, friction, deformation associated with wear, and breakage occur more frequently, with which AE frequently occurs. As a result, a dense continuous waveform was obtained, and an AE with a high DA value and a high RMS value was measured.

  From these results, a relationship is found between the friction coefficient and the DA value-RMS value, and it is considered effective to apply the DA value-RMS value to the friction coefficient estimation.

  The designed value of the coefficient of friction is set to 0.2 as a standard for evaluating the degree of deterioration of the gate pin. Using the design values as a guide, the division was performed as shown in FIG. 6 in the coordinates of the RMS value (V) and the DA value (ms / V) based on the results of FIG. The area of AE confirmed only at a friction coefficient of 0.27 was regarded as dangerous. If the measured AE is plotted in a range showing a value of RMS value 0.003 with a DA value of 2000 or more, it can be inferred that it occurred at a contact surface close to a friction coefficient of 0.27.

  On the other hand, in the AE generated at the contact surface with a coefficient of friction of 0.2, although the RMS value shows a value of 0.003 or more, the AE not in the dangerous area can be confirmed. An AE that is as strong as an AE that falls within the danger zone but does not occur continuously. It is considered that friction and wear do not occur strongly because the waveform is not continuous.

  In order to show a continuous waveform with a DA value of 2000 or more, a waveform having a signal strength of RMS value 0.003 or more needs to frequently appear, and it is considered unlikely to be in the danger zone. On the other hand, a waveform having a DA value of 2000 or more but having no RMS value is a continuous waveform because the DA value is high. Since the RMS value is low, friction and wear do not occur strongly, but it may change to a strong signal by changing to a dense waveform in the future.

  A change to a dense waveform is data that may change in a dense manner if several similar waveforms appear in a few μ, and is a data that may enter a danger area. Therefore, it is considered as an attention area as an area of AE in which it is necessary to carefully check the area where the DA value enters the dangerous area and the RMS value does not enter from now on. In the case where both the DA value and the RMS value are out of the danger zone, this is evaluated as safe. From the above, the identification index as shown in FIG. 7 can be created.

  A flowchart of the operation of the control unit (CPU) 11 of the gate pin inspection device 10 as described above is shown in FIG. As shown in FIG. 8, the control unit 11 acquires AE data (S11), calculates a DA value (S12), calculates an RMS value (S13), associates it with a friction coefficient (S14), and as a result It evaluates (S15) and determines whether it is a safe area, a caution area, or a dangerous area (S16 to S18).

  Next, data was obtained for the case of a corroded flat plate as a different embodiment. Discrimination index created from the result of grinder processed flat plate was applied to the corrosion flat plate. The relationship between the DA value and the RMS value of the AE generated on the contact surface of the corroded flat plate and each moving body is shown as a friction coefficient, and it is divided into a safe area, a caution area and a dangerous area bordering on the DA value 2000 and RMS value 0.003. . AEs plotted in the danger zone are those in which the coefficient of friction is close to 0.27 and are plotted in the danger zone, resulting in satisfying the discrimination index. The results are shown in FIG.

  Next, since the on-site measurement was performed, the result will be described. In order to evaluate the soundness of the radial gate in service, the on-site measurement was performed using the AE method. The identification index was applied to the AE measured at that time.

  Similar to the indoor experiment, it is limited to AE of friction breakage. According to the gate displacement data, it was possible to confirm the gate displacement around 26 s from the start of wire winding. However, due to the deflection of the pedestal, etc., it may be displaced and it is difficult to identify in the bearing. Therefore, the AE measured between 25-28 s is set as the friction breakage with a margin. Also, a waveform with an AE energy of 0 and an AE count of 1 was deleted as noise. Also ch. 1, 2, ch. Of the signals detected by the 3 and 4 pairs, an EDT (event definition time) was provided to select an AE event. EDT was calculated by dividing the distance between sensors (400 mm) by the elastic wave velocity (5, 500 m / s) traveling through the steel plate.

  The results will be described. The result of applying the identification index to the relationship between the DA value and the RMS value of AE at the gate pin is shown in FIG.

  An AE showing a high value falling within the danger zone was not confirmed for both the DA value and the RMS value. The calculated friction coefficient shows a very small value, and it is considered that the environment was not a continuous occurrence of high amplitude AE. In the on-site measurement, it was possible to identify to some extent the identification index created by the laboratory experiment.

  When performing evaluation using an index, it is preferable to determine that it is dangerous when AE which one of the measurement results falls within the danger area is measured among the three measurements. The reason is that although the coefficient of friction was performed six times for each moving object in the indoor experiment, there was also a result in which AE entering the danger area could not be confirmed in the moving object having a high coefficient of friction. Therefore, it is necessary to conduct a plurality of tests.

  In the on-site measurement, it was possible to identify to some extent the identification index created by the laboratory experiment. In the future, we will make classifications finer and propose identification indicators that can estimate the friction coefficient in more detail.

  In the above embodiment, although the case of detecting the frictional force of the gate pin has been described, the present invention is not limited thereto, and a rotating machine capable of estimating deterioration due to similar friction or wear in other mechanical equipment by change in AE signal. Etc. can also be used.

  Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications can be made to the illustrated embodiments within the same scope or equivalent scope of the present invention.

  According to the present invention, a gate pin inspection apparatus capable of inspecting a gate pin can be provided inexpensively and easily, and therefore, the present invention is advantageously used as a gate pin inspection apparatus.

  10 gate pin inspection device, 11 control unit (CPU), 12 waveform acquisition unit, 13 evaluation unit, 14 output unit, 15 AE sensor.

Claims (4)

  Evaluate the friction force of the gate pin using the AE sensor attached to the gate pin, the waveform acquisition unit that acquires the AE waveform from the AE sensor, and the predetermined DA value obtained based on the waveform acquired by the waveform acquisition unit The gate pin test | inspection apparatus containing the evaluation part to do, and the output part which outputs the evaluation result of the said evaluation part.   The gate pin inspection device according to claim 1, wherein the evaluation unit evaluates the frictional force of the gate pin using an RMS value of the waveform acquired by the waveform acquisition unit.   The gate pin inspection device according to claim 2, wherein the evaluation unit identifies the frictional force of the gate pin into a plurality of regions using the AE waveform acquired by the waveform acquisition unit and the RMS value of the AE waveform. A gate pin inspection method for inspecting a frictional force of a gate pin using an AE sensor, comprising:
A gate pin including a step of acquiring an AE waveform from an AE sensor attached to the gate pin, a step of evaluating a frictional force of the gate pin using a predetermined DA value based on the acquired waveform, and an output step of outputting an evaluation result. Inspection method.

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