JP5323627B2 - Weld monitoring unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality monitoring device of a weld zone capable of detecting highly accurately in real time, occurrence of an abnormality in the weld zone of an axle, concerning the axle loaded on a vehicle. <P>SOLUTION: This abnormality monitoring device 10 includes: an AE (Acoustic Emission) sensor 12 arranged on the outer circumferential surface of a shaft body 2, for detecting an AE wave generated in the weld zone 5; and a determination part 15 for setting a sample line from a moving average &mu; and a standard deviation &sigma; calculated from a prescribed extraction width in output signals from the AE sensors 12, determining whether the AE wave having an output signal higher than a prescribed threshold is detected or not, based on the number of times wherein each output signal agrees with a value of the sample line, and determining occurrence of an abnormality in the weld zone 5 based thereon. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an abnormality monitoring device for a welded portion of an axle provided in an automobile.

  A specially equipped vehicle such as a truck is equipped with an axle as an axle of a traveling device. As shown in Patent Document 1, the axle is formed by welding a spindle having a tapered portion whose diameter increases toward the shaft main body side at the end of the cylindrical shaft main body. Since the axle is an important part related to the running of the vehicle, before shipping the axle, non-destructive inspection such as ultrasonic flaw detection and X-rays is conducted to check whether there is an abnormality in the welded part of the shaft body and spindle. Thorough inspection has been conducted.

Japanese Patent Laid-Open No. 11-115405

  However, since the axle is a part that repeatedly receives a vehicle load and an impact during traveling, there is a possibility that cracks or the like may occur with the passage of time. For this reason, it is preferable to detect in real time and with high accuracy that an abnormality has occurred in the axle mounted on the vehicle.

  An object of the present invention is to provide an abnormality monitoring device for a welded part capable of detecting an occurrence of an abnormality in a welded part of an axle in real time and with high accuracy in an axle mounted on a vehicle.

  In order to solve the above-described problems, the abnormality monitoring apparatus for a welded portion of the present invention is mounted on a vehicle having an axle formed by welding a spindle to an end of a cylindrical shaft body, and an abnormality of a welded portion in the axle is generated. An abnormality monitoring device for a welded portion that monitors the presence or absence of an AE, an AE sensor that is disposed on the outer peripheral surface of the shaft body and that detects an AE (Acoustic Emission) wave generated at the welded portion, and a predetermined output signal from the AE sensor A sample line is set from the moving average value and the standard deviation calculated from the extracted width of the signal, and it is determined whether or not an AE wave having an output signal equal to or greater than a predetermined threshold is detected based on the number of times the output signal matches the value of the sample line And a determination unit that determines whether or not an abnormality has occurred in the welded portion based on this.

  According to this welding part abnormality monitoring device, an AE sensor is arranged on the outer peripheral surface of the shaft body, and based on an output signal from the AE sensor that detects an AE wave generated when a crack occurs in the welding part, the welding part It is determined whether or not an abnormality has occurred in The detection function of the AE sensor does not detect vibration generated when the vehicle travels, and therefore can detect only vibration generated by the occurrence of a crack. Therefore, it is possible to detect in real time that a crack has occurred by constantly monitoring the AE wave from the weld with the AE sensor. Furthermore, in this abnormality monitoring apparatus, since a certain process is performed on the output signal from the AE sensor, it is possible to accurately determine whether or not an abnormality has occurred in the welded portion.

  Further, in the abnormality monitoring device for a welded portion, an impact sensor that detects a shock wave is disposed adjacent to the AE sensor on the outer peripheral surface of the shaft body, and the determination unit calculates from a predetermined extraction width in the output signal from the impact sensor. It is preferable to set a sample line from the moving average value and the standard deviation, and determine whether or not a shock wave having an output signal equal to or greater than a predetermined threshold is detected based on the number of times the output signal matches the value of the sample line. Further, in the abnormality monitoring device for a welded portion, the determining unit determines that an abnormality has occurred in the welded portion when it is determined that an AE wave equal to or greater than a predetermined threshold is detected and a shock wave equal to or greater than the predetermined threshold is not detected. It is preferable to do. Further, in the abnormality monitoring device for a welded portion, the determination unit determines that an abnormality has not occurred in the welded portion when it is determined that an AE wave equal to or greater than a predetermined threshold is detected and a shock wave equal to or greater than the predetermined threshold is detected. It is preferable to determine.

  In this abnormality monitoring apparatus for a welded portion, the shock sensor can detect a shock wave having a predetermined frequency that cannot be determined by the AE sensor. This makes it possible to discriminate between vibration generated by impact and vibration generated when an abnormality occurs in the welded part, even when pebbles, etc. that are thrown up by a vehicle equipped with an axle collide with the axle. Therefore, it is possible to detect the occurrence of abnormality in the welded portion of the axle with higher accuracy.

  Moreover, it is preferable that the abnormality monitoring device for a welded part further includes a notifying part for notifying the determination result when the determining part determines that an abnormality has occurred in the welded part. Thereby, for example, an abnormality occurring in the axle can be recognized by the driver or manager of the vehicle.

  In addition, it is preferable that the abnormality monitoring device for a welded portion further includes a control unit that prohibits traveling of the vehicle when the determining unit determines that an abnormality has occurred in the welded portion. As a result, it is possible to avoid problems caused by the occurrence of an abnormality in the axle.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the abnormality in the welding part of an axle can be detected in real time and with high precision in the axle mounted in the vehicle.

It is the schematic of the axle with which the abnormality monitoring apparatus of the welding part which concerns on suitable one Embodiment of this invention is attached. It is sectional drawing to which the welding part vicinity of the axle of FIG. 1 was expanded. It is the block diagram which showed the function structure of the abnormality monitoring apparatus of the welding part which concerns on suitable one Embodiment of this invention. It is a figure which shows an example of the signal output from the AE sensor of FIG. It is a figure explaining the waveform processing analysis in the signal processing part of FIG. It is a flowchart which shows the flow of a process of the abnormality monitoring apparatus of the welding part which concerns on suitable one Embodiment of this invention. It is a figure which shows an example of the signal output from the AE sensor of FIG. It is a figure explaining the waveform processing analysis result in the signal processing part of FIG. It is the block diagram which showed the function structure of the abnormality monitoring apparatus of the welding part which concerns on other preferable one Embodiment of this invention. It is a figure explaining the detection function of the AE sensor of FIG. 9, and an impact sensor. It is a figure which shows an example of the determination table in the determination part of FIG.

[First Embodiment]
A welded portion abnormality monitoring apparatus 10 according to a preferred first embodiment of the present invention will be described with reference to FIGS. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted. FIG. 1 is a schematic view showing an axle 1 to be inspected by a weld monitoring abnormality monitoring device of the present invention.

  The axle 1 to be monitored by the welded portion abnormality monitoring device 10 of the present invention is an axle of a traveling device mounted on a specially equipped vehicle such as a truck. As shown in FIGS. 1 and 2, the axle 1 is formed by welding a spindle 3 having a tapered portion 3b having a large diameter toward the end of the shaft body 2 at the end of the cylindrical shaft body 2. Yes. The shaft body 2 is a hollow cylindrical member having a thickness of 9 mm, for example. The spindle 3 includes a joint portion 3a that is a portion to be joined to the shaft body 2, a taper portion 3b that changes so that the cylinder diameter increases toward the shaft body 2, and a portion for attaching a hub to the outer peripheral surface. And a certain attachment portion 3c.

  The spindle 3 and the shaft body 2 are welded, for example, by automatic welding using a welding robot. In this welding, for example, as shown in FIG. 2, the groove portion 3d of the spindle 3 and the groove portion 2a of the shaft body 2 abut each other, and a backing member 4 is provided on the inner peripheral surface side of the abutted position. The torch of the welding robot is applied from the outer peripheral surface side. Then, by rotating a member that forms a torch or an axle along a joint surface where the groove portions 3d and 2a abut each other, a circle is formed between the end portion of the spindle 3 and the end portion of the shaft body 2. A circumferential weld 5 is formed.

  Hereinafter, an abnormality monitoring apparatus 10 for monitoring whether or not an abnormality has occurred in the welded portion 5 in the axle 1 formed by welding the spindle 3 and the shaft body 2 as described above will be described with reference to FIGS.

  The abnormality monitoring device 10 is mounted on a vehicle including the axle 1 described above, and as shown in FIG. 3, the AE sensor 12, the signal processing unit 13, the determination unit 15, the notification unit 16, and the control unit. 17.

  The AE sensor 12 is fixed to the outer peripheral surface of the shaft body 2, and is a part that detects the AE wave generated when a crack is generated or progresses in the welded portion 5 by the shaft body 2. The AE sensor 12 has a characteristic of detecting only vibrations in a frequency band of several tens of kHz to several MHz which is much higher than vibrations received during normal traveling. The AE sensor 12 outputs an output signal corresponding to the detected intensity of the AE wave to the signal processing unit 13 via an amplifier (not shown) whose band frequency is 40 kHz to 1.2 MHz, for example. The output from the AE sensor 12 to the signal processing unit 13 may be either wired or wireless.

  FIG. 4 is a diagram illustrating an example of a signal output from the AE sensor 12 when a crack occurs in the welded part 5 or when a crack develops in the welded part 5. The AE sensor 12 does not output any signal when there is no abnormality in the welded portion 5, but the AE wave that propagates to the shaft body 2 when the welded portion 5 cracks or progresses. For example, as shown in FIG. 4, a signal having an amplitude peak first and gradually decreasing is output.

  The signal processing unit 13 is a part that extracts a determination value necessary for determining whether or not an abnormality has occurred in the welded part 5 from the output signal detected by the AE sensor 12. The signal processing unit 13 characterizes the output signal by waveform processing analysis so that the determination unit 15 to be described later can make an objective determination when determining whether or not an abnormality has occurred in the welded portion 5.

  Hereinafter, waveform processing analysis which is one of the processes performed by the signal processing unit 13 will be described. In this waveform processing analysis, first, as shown in FIG. 5, a moving average value μ of the output signal in a predetermined extraction width is obtained. Next, a sample line is set based on the standard deviation σ of the moving average value μ. The sample line can be obtained by multiplying the standard deviation σ by a predetermined value. For example, as shown in FIG. 5, by multiplying the standard deviation σ by −3.0 times, −1.5 times, +1.5 times, and +3.0 times, a sample line of −3σ, −1.5σ of A sample line, a sample line of + 1.5σ, and a sample line of + 3.0σ can be obtained. Next, the number of times that the output signal matches the value of a predetermined sample line (for example, + 3σ sample line) is calculated. The signal processing unit 13 sets this number of times as a determination value and outputs the determination value to the determination unit 15.

  The determination unit 15 determines whether or not an AE wave having an output signal equal to or greater than a predetermined threshold is detected based on the determination value calculated by the signal processing unit 13 and determines whether or not an abnormality has occurred in the welded portion 5. It is a part to do. Specifically, when the number of times the output signal matches the value of the sample line satisfies the reference data, the determination unit 15 determines that an AE wave having an output signal equal to or greater than a predetermined threshold is detected, and based on this, When it is determined that an abnormality has occurred in the weld 5 and the number of times the output signal matches the value of the sample line does not satisfy the reference data, it is determined that an AE wave having an output signal equal to or greater than a predetermined threshold has not been detected. Based on the above, it is determined that no abnormality has occurred in the welded portion 5. The reference data is a value set for each sample line obtained by multiplying the standard deviation σ by a predetermined value, and is stored in the database unit 14. The determination unit 15 is provided on the outer peripheral surface of the shaft body 2.

  When the determination unit 15 determines that an abnormality has occurred in the welded part 5, the notification unit 16 is a part that notifies the driver or administrator of the vehicle on which the axle 1 is mounted. The notification unit 16 notifies, for example, that an abnormality has occurred in the welded part 5 as a warning sound, or displays that an abnormality has occurred in the welded part 5 on a display unit or the like of the vehicle.

  The control part 17 is a part which prohibits the driving | running | working of the vehicle by which the axle 1 is mounted, when the determination part 15 determines with the abnormality in the welding part 5. FIG. For example, when the vehicle is running, the control unit 17 controls the brake of the vehicle to stop the vehicle, and when the vehicle is stopped, controls the engine to stop so that the vehicle runs. Is prohibited.

  Hereinafter, the operation of the abnormality monitoring device 10 of the welded portion 5 described above will be described using a flowchart showing the flow of processing of the abnormality monitoring device 10 of the welded portion 5 shown in FIG. The AE sensor 12 constantly monitors the AE wave generated in the welded portion 5. When the AE wave is detected, the AE sensor 12 outputs an output signal corresponding to the detected intensity of the AE wave to the signal processing unit 13 (step S1).

  Next, the signal processing unit 13 extracts a determination value necessary for determining whether or not an abnormality has occurred in the welded part 5 from the output signal acquired by the AE sensor 12 (step S2). Specifically, as shown in FIG. 7, first, a moving average value μ within a predetermined extraction width (in the example of FIG. 7, 150 ns that is the period of the AE wave) is obtained for the signal output from the AE sensor 12, and the movement is performed. A standard deviation σ based on the average value μ is calculated. Next, a sample line obtained by multiplying the calculated standard deviation σ by a predetermined value (in the example of FIG. 7, three times the standard deviation σ) is set. Then, the number of times that the output signal matches the value of the sample line is calculated, and the determination value is acquired as shown in FIG. The determination value shown in FIG. 8A is calculated by counting when the output signal M1 shown in FIG. 7 exceeds the value of the sample line 3σ and when it falls below the sample line 3σ. .

  Next, based on the determination value extracted in step S2, the determination unit 15 determines whether or not an abnormality has occurred in the welded part 5 (step S3). Specifically, as shown in FIG. 8A, the determination unit 15 has a predetermined threshold value or more if the output signal matches the value of the sample line at least once for the + 3σ sample line. It is determined that an AE wave having an output signal has been detected, and based on this, it is determined that an abnormality has occurred in the welded portion 5. On the other hand, as shown in FIG. 8B, when the output signal does not match the value of the sample line for the + 3σ sample line, the determination unit 15 has an AE wave having an output signal equal to or greater than a predetermined threshold value. Is determined not to be detected, and based on this, it is determined that no abnormality has occurred in the welded part 5. Here, although the number of times that the output signal matches the value of the sample line with respect to the sample line 3σ is one or more times, the determination criterion for determining that an abnormality has occurred in the welded portion 5 is used, but the present invention is not limited to this. It is not something. For example, this determination value is obtained for each sample line obtained by multiplying the standard deviation σ by a predetermined value based on the result of waveform processing analysis of a time series waveform obtained from an AE wave generated when an abnormality occurs in the welded portion 5. Can be set to

  In step S3, when it is determined that an abnormality has occurred in the welded portion 5 (step S3: present), the notification unit 16 outputs a warning sound to indicate that an abnormality has occurred in the welded portion 5 of the axle 1. The vehicle driver is notified (step S4). Next, when the vehicle is running, the control unit 17 controls the brake of the vehicle to stop the vehicle, and when the vehicle is stopped, the control unit 17 controls the engine to stop or start the engine. The vehicle is prohibited from traveling (step S5).

  On the other hand, if it is determined in step S3 that no abnormality has occurred in the welded portion 5 (step S3: none), the series of processes is terminated.

  As described above, according to the abnormality monitoring device 10 for the welded portion 5 of the present embodiment, vibrations in the frequency band of several tens kHz to several MHz generated when a crack occurs or when the crack progresses are detected by the AE sensor 12. Can be detected. Since the detection function of the AE sensor 12 does not detect vibrations generated when the vehicle is traveling, only vibrations generated by the occurrence or development of cracks can be detected. Moreover, according to the abnormality monitoring apparatus 10 of the welded part 5 of this embodiment, since the AE sensor 12 constantly monitors the AE wave from the welded part 5, it detects in real time that a crack has occurred or has progressed. be able to. Furthermore, since the determination unit 15 performs determination based on the determination value extracted in step S2 with respect to the output signal from the AE sensor 12, it is accurately determined whether or not an abnormality has occurred in the welded portion 5. can do. As a result, it is possible to detect in real time and with high accuracy that an abnormality has occurred in the welded portion 5 of the axle 1 mounted on the vehicle.

[Second Embodiment]
An abnormality monitoring apparatus 110 for the welded part 5 according to a preferred second embodiment of the present invention will be described with reference to FIGS. Note that the configuration of the abnormality monitoring apparatus 110 is different from the abnormality monitoring apparatus 10 of the first embodiment in that the impact sensor 21 is provided, and only the determination process in the determination unit 15 is different. Hereinafter, the different points will be mainly described, and the description of the same elements given the same numbers will be omitted.

  As shown in FIG. 9, the impact sensor 21 is fixed adjacent to the AE sensor 12 on the outer peripheral surface of the shaft body 2. The frequency band of the impact sensor 21 is, for example, about several Hz to several kHz, and covers a lower frequency band than the AE sensor 12. The impact sensor 21 outputs an output signal corresponding to the detected intensity of the shock wave to the signal processing unit 13. The signal processing unit 13 performs waveform analysis processing similar to that of the first embodiment on the output signals from the AE sensor 12 and the impact sensor 21, and indicates whether or not an AE wave / shock wave equal to or greater than a predetermined threshold is detected. The determination value is output to the determination unit 15. The output from the impact sensor 21 to the signal processing unit 13 may be either wired or wireless.

  FIG. 10 is a diagram illustrating detection functions of the AE sensor and the impact sensor. As shown in FIG. 10, the frequency of the shock wave generated by the vibration when the vehicle travels or the collision of the pebbles or the like with the axle 1 is, for example, several Hz to several tens kHz. Therefore, when a shock wave propagates through the axle 1, it can be detected by the shock sensor 21. Note that the high frequency band portion of the shock wave may be detected by the AE sensor 12. Further, the AE wave generated by the occurrence or development of the crack is not detected by the impact sensor 21 but can be detected only by the AE sensor 12.

  FIG. 11 is a diagram illustrating an example of a determination table in the determination unit 15. As shown in FIG. 11, the determination unit 15 detects a signal that is greater than or equal to a predetermined threshold when neither the impact sensor 21 nor the AE sensor 12 is detected. In the case, it is determined that no abnormality has occurred in the welded portion 5. The determination unit 15 also determines that no abnormality has occurred in the welded part 5 even when both the impact sensor 21 and the AE sensor 12 detect a signal equal to or greater than a predetermined threshold. This is because the AE sensor 12 may detect the high frequency band portion of the shock wave as described above. And the determination part 15 determines with abnormality having occurred in the welding part 5, when the signal more than a predetermined threshold value is detected only by the AE sensor 12. FIG.

  As described above, according to the abnormality monitoring device 110 of the welded part 5 of the present embodiment, the impact sensor 21 is provided adjacent to the AE sensor 12 in addition to the same effects as those of the abnormality monitoring device 10 of the above embodiment. Therefore, it is determined whether or not an abnormality has occurred in the welded portion 5 based on a determination table as shown in FIG. As a result, the AE wave, which is propagated to the axle 1, for example, is detected from the AE wave caused by the occurrence of a crack, the shock wave caused by the collision of a flying object, the vibration at the time of traveling, etc. The presence or absence of can be detected with higher accuracy.

  The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above embodiment. The present invention can be modified in various ways as described below without departing from the scope of the invention.

  In the said embodiment, although the alerting | reporting part 16 gave and demonstrated the example which alert | reports to the driver | operator of a vehicle that the crack generate | occur | produced in the welding part 5, for example, it communicates with the manager of the said vehicle in a remote place, etc. You may make it alert | report via a means. In this case, it is possible to notify the manager together with the position of the vehicle by mounting current position specifying means such as GPS on the vehicle. In addition, it is possible to notify the manager together with the travel distance by cooperating with travel distance specifying means such as an integrating meter mounted on the vehicle. As a result, the state of the vehicle can be managed more precisely.

  In the above embodiment, the determination unit 15 determines whether or not an AE wave having an output signal equal to or greater than a predetermined threshold is detected, and determines whether or not an abnormality has occurred in the welded part 5. It may be determined whether or not an AE wave having an amplitude of, for example, 20% or more of the maximum amplitude that can be measured is detected, and whether or not an abnormality has occurred in the welded portion 5 may be determined.

  In the abnormality monitoring devices 10 and 110 of the welded part 5 of the above embodiment, 3σ, which is three times the standard deviation σ, is set when setting the sample line. However, the present invention is not limited to this. You may set 1.5 (sigma) 5 times, 6 (sigma) 6 times the standard deviation (sigma), etc.

  DESCRIPTION OF SYMBOLS 1 ... Axle, 2 ... Shaft body, 2a ... Groove part, 3 ... Spindle, 3a ... Joint part, 3b ... Tapered part, 3c ... Mounting part, 3d ... Groove part, 5 ... Weld part, 10 ... Abnormality monitoring apparatus , 12 ... AE sensor, 13 ... signal processing unit, 14 ... database unit, 15 ... determination unit, 16 ... notification unit, 17 ... control unit, 21 ... impact sensor, 110 ... abnormality monitoring device.

Claims (6)

An abnormality monitoring device for a welded part that is mounted on a vehicle having an axle formed by welding a spindle to an end of a cylindrical shaft body, and that monitors the occurrence of an abnormality of the welded part in the axle,
An AE sensor that is disposed on an outer peripheral surface of the shaft body and detects an AE wave generated in the weld;
A sample line is set from a moving average value and a standard deviation calculated from a predetermined extraction width in an output signal from the AE sensor, and an output signal equal to or greater than a predetermined threshold is determined by the number of times the output signal matches the value of the sample line. A determination unit that determines whether or not an AE wave is detected and determines whether or not an abnormality has occurred in the weld based on the AE wave;
An abnormality monitoring device for a welded portion, comprising: On the outer peripheral surface of the shaft body, an impact sensor for detecting a shock wave is disposed adjacent to the AE sensor,
The determination unit sets a sample line from a moving average value and a standard deviation calculated from a predetermined extraction width in an output signal from the impact sensor, and determines a predetermined threshold value based on the number of times the output signal matches the value of the sample line. The apparatus for monitoring abnormality of a welded portion according to claim 1, wherein it is determined whether or not a shock wave having the above output signal is detected.   The determination unit determines that an abnormality has occurred in the weld when it is determined that the AE wave equal to or greater than the predetermined threshold is detected and the shock wave equal to or greater than the predetermined threshold is not detected. The abnormality monitoring device for a welded portion according to claim 2.   The determination unit determines that no abnormality has occurred in the weld when it is determined that the AE wave equal to or greater than the predetermined threshold is detected and the shock wave equal to or greater than the predetermined threshold is detected. The weld monitoring abnormality monitoring device according to claim 2 or 3, characterized in that:   5. The apparatus according to claim 1, further comprising a notification unit that notifies the determination result when the determination unit determines that an abnormality has occurred in the welded portion. Abnormality monitoring device for welds.   The control part which prohibits driving | running | working of the said vehicle, when it determines with abnormality in the said welding part having generate | occur | produced in the said determination part, The any one of Claims 1-5 characterized by the above-mentioned. An abnormality monitoring device for welded parts.

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