JP2019027897A - Leakage monitoring system for monitoring multiple air apparatuses - Google Patents

Abstract

To solve the problem of a production device in which an apparatus operating upon receiving the supply of compressed air is disposed in plurality, that in order to efficiently repair or replace components it is important not just to detect the leakage of compressed air but also specify an apparatus or supply path where leakage has occurred, but prior art requires that a large number of sensors be installed in order for a spot where leakage has occurred to be specified.SOLUTION: Information is prepared in advance that pertains to a plurality of air leakage detection reference values that are set in correspondence to the different operating states of a plurality of air apparatuses included in the operation sequence of a production device. A discretionary air leakage detection reference value among the plurality of air leakage detection reference values is compared with a signal inputted from a microphone during an operating state that corresponds to the air leakage detection reference value, and an air apparatus in which air leakage has occurred is specified.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a leakage monitoring system for monitoring leakage of compressed air in an apparatus system including a plurality of air devices that operate by receiving supply of compressed air. In particular, the present invention relates to a leakage monitoring system suitably used in a production apparatus system including a plurality of air devices such as air cylinders and air blowers.

  Conventionally, many production devices such as air cylinders that operate by receiving compressed air supply have been used. However, if compressed air leaks from such devices or piping, the production device will not operate normally. . Therefore, in order to maintain the apparatus, preventive maintenance has been performed in which inspection, repair, parts replacement, etc. are performed at regular intervals. In the preventive maintenance, since the production apparatus is stopped and inspected at a short cycle, there is a problem that the production efficiency is lowered and a lot of man-hours are required. On the other hand, if the interval period until the next inspection is lengthened, even if the compressed air starts to gradually leak during that time, it may not be discovered until the operation of the apparatus during the production process is hindered.

In recent years, in response to such problems, production equipment is operated while being monitored by sensors, etc., and parts are replaced, repaired, and updated according to the deterioration state, thereby reducing unnecessary parts replacement and labor costs. The idea of predictive maintenance that realizes this has been proposed.
Patent Document 1 describes a device in which a flow meter is arranged in a compressed air circuit, and flow rate data is transmitted to a monitoring computer and constantly monitored.
Patent Document 2 describes a device that collects sound from a monitoring target with an ultrasonic microphone and detects a fluid leak from the sound data.

JP 2003-294503 A JP-A-11-51300

In production equipment with multiple devices that operate by receiving compressed air supply, in order to efficiently perform repairs and parts replacement work, not only the occurrence of compressed air leakage is detected, but also leakage is detected. It is important to identify the equipment or supply path that has occurred.
However, in the prior art, it is necessary to install a large number of sensors in order to be able to identify the location where the leakage has occurred.

  In the method of Patent Document 1, in order to specify the position and device where air leakage has occurred, it is necessary to provide flow meters at a number of locations such as a branch point of the compressed air supply path and connection points with each device. In addition, pipes with a large flow rate and devices that consume a lot of air need to be equipped with a flow meter with a large measurement range (maximum flow rate), which may reduce the sensitivity to minute flow rate changes, resulting in leakage. May be overlooked.

  In the method of Patent Document 2, in order to specify the position and device where air leakage has occurred, it is necessary to install ultrasonic microphones at a number of locations such as pipes and the vicinity of each device. In production equipment, equipment is often densely arranged, but not only a large number of ultrasonic microphones are required, but there is also the possibility of overlooking the occurrence of leakage due to noise generated by surrounding equipment. .

  As described above, in the conventional method, it is necessary to install a large number of sensors, the signal wiring from the sensors increases, the communication speed increases, the data processing becomes complicated, and the apparatus cost increases. In addition, there are cases where the sensitivity to minute flow rate changes is insufficient, or the S / N ratio decreases due to the noise generated by the production equipment, so that the occurrence of leakage cannot be detected at an early stage. There is also a risk that leakage will increase to such a level as to cause trouble. If the leakage increases to a level that hinders the operation, it is necessary to stop the production and repair it, which causes problems such as a review of the operation plan and a decrease in productivity.

  The present invention has a plurality of air devices that operate by receiving a supply of compressed air, a microphone that can detect ultrasonic waves, and a control unit, and the control unit performs an operation sequence of the plurality of air devices. Information on a plurality of air leak detection reference values set corresponding to different included operating states is acquired in advance, an arbitrary air leak detection reference value among the plurality of air leak detection reference values, and the air leak detection Compared with the signal input from the microphone in the operation state corresponding to the reference value, and the signal input from the microphone exceeds the air leakage detection reference value, the air leakage detection reference value A leakage monitoring system for monitoring a plurality of air devices, characterized in that an air device in which an air leak has occurred is identified based on the corresponding operating states of the plurality of air devices.

  Further, the present invention is a production system including a production apparatus including a plurality of air devices that operate by receiving supply of compressed air, a microphone capable of detecting ultrasonic waves, and a control unit, wherein the control unit Obtains in advance information on a plurality of air leak detection reference values set corresponding to different operation states of the plurality of air devices included in the operation sequence of the production apparatus, and sets the plurality of air leak detection reference values. An arbitrary air leak detection reference value in the medium is compared with a signal input from the microphone in an operation state corresponding to the air leak detection reference value, and the signal input from the microphone is compared with the air leak detection reference value. When the value is exceeded, the production system is characterized in that the air device in which the air leakage has occurred is specified based on the operation state of the plurality of air devices corresponding to the air leakage detection reference value.

  Further, the present invention provides a method for manufacturing an article using a production system including a production apparatus including a plurality of air devices that operate by receiving supply of compressed air, a microphone capable of detecting ultrasonic waves, and a control unit. The control unit acquires in advance information on a plurality of air leak detection reference values set corresponding to different operation states of the plurality of air devices included in the operation sequence of the production apparatus, Comparing an arbitrary air leak detection reference value in the air leak detection reference value with a signal input from the microphone in an operation state corresponding to the air leak detection reference value at the time of manufacturing the article, When the signal input from the microphone exceeds the air leak detection reference value, the air device in which the air leak has occurred is identified based on the operating state of the plurality of air devices corresponding to the air leak detection reference value. It is a manufacturing method of an article characterized by.

  The present invention provides a monitoring system capable of monitoring the leakage of compressed air in a plurality of air devices with a small number of sensors and identifying the air device related to the leakage when the leakage occurs. Can be provided.

The schematic diagram which shows the structure of the production line of embodiment. The block diagram of the monitoring apparatus of embodiment. The flowchart of monitoring in an embodiment. A simple sectional view of an air cylinder. (A) The figure which shows the state of the air cylinder protruding. (B) The figure which shows the air leakage in the state of the insertion of an air cylinder. The figure which showed typically a part of production apparatus of Example 1. FIG. 3 is a time chart showing an operation sequence of the leakage monitoring system according to the first embodiment. 6 is a time chart illustrating an operation sequence of the leakage monitoring system according to the second embodiment. The figure which showed a part of production apparatus of Example 3 typically. In the leak monitoring system of Example 3, the time chart which shows the sequence which sets a threshold value and an amplification factor. The figure which showed a part of production apparatus of Example 4 typically. In the leak monitoring system of Example 4, the time chart which shows the sequence which selects a microphone. The figure which showed typically a part of production apparatus of Example 5. FIG. In the leakage monitoring system of Example 5, the time chart which shows the switching sequence of monitoring operation | movement. 10 is a time chart showing an operation sequence of the leakage monitoring system according to the sixth embodiment. The figure which showed a part of production apparatus of Example 7 typically. (A) In Example 7, the time chart which shows the operation | movement sequence of the leakage monitoring system by the side of one production apparatus. (B) In Example 7, the time chart which shows the operation | movement sequence of the leakage monitoring system by the side of the other production apparatus.

Hereinafter, a production system including a leakage monitoring system according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a production line according to an embodiment of the present invention.

  In the production line 73, production apparatuses 70 to 72 are arranged side by side. The production apparatuses 70 to 72 are facilities for manufacturing articles by processing or assembling parts or the like. In the production apparatuses 70 to 72, air cylinders 50, 51, 53, 54, 56, and 57 for supplying driving force for processing and assembling products, parts, and the like are arranged. In addition, other devices such as a vacuum adsorber 52, an air blow 55, and the like that operate by receiving compressed air are also provided. In addition, air pipes 63 and 64 for supplying compressed air to each device and electromagnetic valves 40 and 41 for controlling the amount of compressed air supplied and switching the flow path when the article is manufactured are also provided.

  In the following description, devices and parts related to compressed air, such as air cylinders, vacuum adsorbers, air blowers, air pipes, and electromagnetic valves, may be collectively referred to as air devices. That is, the production apparatuses 70, 71, 72 are provided with the air devices 45, 46, 47 in the order described.

The production apparatuses 70, 71, 72 include control apparatuses 30, 31, 32 in the order described in order to control the air devices 45, 46, 47. The control devices 30 to 32 control the operation and timing of the air equipment included in each production device according to the control program.
In order to monitor abnormalities in the air equipment, each production device is provided with one or more microphones and a monitoring device. That is, in this embodiment, the production apparatuses 70, 71, and 72 include the microphones 10, 11, and 12, and the monitoring apparatuses 20, 21, and 22 in the order described.

  The monitoring devices 20 to 22 are connected to the control devices 30 to 32, and can acquire information related to the operating state of the air devices 45 to 47 from the control devices 30 to 32. The monitoring devices 20 to 22 may be configured by an electric circuit device (including a computer) different from the control devices 30 to 32, or may be configured to be incorporated in the control devices 30 to 32. . The monitoring devices 20 to 22 may be paraphrased as control units that control the air leakage monitoring operation.

  The monitoring devices 20 to 22 and the control devices 30 to 32 are connected to a network in the factory via networks 90 and 91. The production system according to the present embodiment includes a monitoring computer 80 that monitors the state of each production apparatus. Is possible. That is, the monitoring computer 80 can check the status of the monitoring devices 20 to 22 and the control devices 30 to 32 in a timely manner. In addition, the monitoring devices 20 to 22 and the control devices 30 to 32 in the same network can communicate with each other via the networks 90 and 91.

  FIG. 2 is a block diagram schematically showing a block configuration of the monitoring device 20 of the present embodiment. Although the monitoring devices 21 and 22 have the same block configuration, a duplicate description is omitted.

The monitoring device 20 includes a microphone input 110 as a terminal to which an electric signal is input from the microphone 10. One or more microphones 10 are installed in the production apparatus 70, and the sound is converted into an analog electric signal and input to the microphone input 110.
The monitoring device 20 includes a signal amplifier 120 capable of changing an amplification factor for amplifying an analog signal input to the microphone input 110, a switch 121 for selecting one of the amplified signals, and a digital signal from the analog signal. An AD converter 122 for converting into a signal is provided.
In addition, the monitoring device 20 includes a comparator 160 that compares the acoustic data converted into a digital value by the AD converter 122 and the threshold value 150.

  Here, the threshold value 150 is a threshold value for determining whether or not compressed air leaks, and a different value is set depending on which of the air devices 45 included in the production apparatus 70 is in operation. ing. That is, since the production apparatus 70 operates according to a predetermined operation sequence, the air cylinders 50 and 51 and the vacuum suction device 52 operate at a predetermined timing. If compressed air leaks, the volume of the ultrasonic wave due to the leak varies depending on which device is used, and the background sound level depends on whether other devices (including those other than air devices) are operating. It is also different. Therefore, it is necessary to change the threshold according to the timing at which the production apparatus 70 is operating or the operating status. In other words, the threshold value 150 is a plurality of air leak detection reference values set corresponding to different operation states included in the operation sequences of the plurality of air devices.

The monitoring device 20 includes a monitoring switch 170 that switches between enabling and disabling monitoring according to the operating state of the air device 45 in order to prevent the comparator 160 from erroneously detecting.
In addition, the monitoring device 20 includes a state acquisition unit 130 that acquires information regarding the operating state of the air device 45 from the networks 90 and 91 via the control device 30. Moreover, the table 140 for changing the operation parameter of each part according to the operating state of the air apparatus 45 is provided. In the table 140, the amplification factor of the signal amplifier 120 to be set according to the operating state of the air device 45, the analog signal selection of the microphone switch 121, the conversion timing of the AD converter 122, the value of the threshold value 150 of whether or not leakage occurs The operation information of the monitoring switching 170 is stored.

  When it is determined that the comparator 160 is abnormal and the monitoring is valid, the monitoring device 20 identifies an abnormal device based on the operating state of each device included in the air device 45 and performs monitoring via the network controller 95. Notification is made to the computer 80 via the notification device 180.

  FIG. 3 is a flowchart of processing in which the monitoring devices 20, 21, and 22 monitor the air devices of the production devices 70 to 72. Here, a process for performing abnormality monitoring on an arbitrary device in the production apparatus will be described.

First, the state acquisition unit 130 of the monitoring device 20 acquires information on the operating state and operation sequence of the air device 45 from the control device 30. (Step S10).
Here, the information on the operating state and the operation sequence of the air device 45 is information on the current operating state of the air device 45 and the operation of the air device 45 to be executed next. Acquisition of information by the monitoring device 20 may be performed at regular time intervals, or may be acquired when the state of the air device 45 changes.

The monitoring device 20 identifies the operating air device from the acquired information on the operating state of the air device 45, and the amplification factor of the signal amplifier 120 used for detecting an abnormality (compressed air leakage) of the device, The setting of the switch 121 and the setting of the AD converter 122 are changed. (Step S20).
For example, when the operating air device is an air cylinder having a stroke of 50 mm or less and a piston diameter of 30 mm or less, even if a small amount of air leakage occurs, the influence on the operation is large. Therefore, it is necessary to be able to detect even a small amount of air leakage. However, since the generated sound is small and the signal strength of the microphone is weak, the gain of the signal amplifier 120 is increased or the threshold 150 is set low. As described above, it is possible to prevent erroneous detection and oversight by changing the operating condition of the monitoring device 20 according to the operating state of the air device 45.

The monitoring device 20 starts signal measurement of the microphone 10 (step S30) and waits for the operation of the air device 45 to be completed. (Step S40).
After the operation of the air device 45 is completed, the comparator 160 compares the threshold value 150 set in advance according to the operating state of the air device 45 and the microphone value 190. (Step S50).

  If it is within the normal range, that is, if the microphone value 190 is less than the threshold value 150, the air leakage is not detected and the process returns to the device state acquisition (step S10). On the other hand, when the microphone value 190 is greater than or equal to the threshold value 150, it is determined that there is an air leak in a device that is operating, that is, supplied with compressed air. The monitoring device 20 notifies the monitoring computer 80 of the occurrence of an abnormality from the notification device 180 via the network controller 95 and the networks 90 and 91 in the factory. That is, it is notified which air device has an air leak. (Step S60).

Note that the reason for waiting for the completion of the operation of the air device 45 in step S40 is that it is advantageous for measurement because the S / N ratio is higher when waiting for the background sound generated by the peripheral device to be reduced. However, if the S / N ratio can be ensured without waiting for the completion of the operation, step 40 may be skipped and the process may proceed directly from step S30 to step S50.
Further, instead of notifying the monitoring computer 80 of the detection result only when a leak is detected in step S50, the detection result may be always notified to the monitoring computer 80 regardless of the presence or absence of leakage.

  First, an air cylinder will be described as an example of an air device that is an air leak detection target in the following embodiments. FIG. 4 is a simplified cross-sectional view showing the structure of the air cylinder. The air cylinder 200 controls the movement of the piston rod 210 using compressed air as a power source. The piston rod 210 is connected to the piston 220, and the air on both sides of the piston 220 is separated by surrounding the piston 220 with a piston packing 221 and closely contacting the cylinder. The piston rod 210 is surrounded by a rod packing 211 to maintain the pressure inside the cylinder.

  When compressed air 212 is supplied from the rod-side breathing hole 213, the pressure on the left side of the piston 220 increases, and the piston 220 moves in the direction of the right arrow 290. On the other hand, when compressed air 232 is supplied from the piston-side breathing hole 233, the pressure on the right side of the piston 220 increases, and the piston 220 moves in the direction of the left arrow 280.

Next, an example in which compressed air leaks in such an air cylinder will be described. FIG. 5A and FIG. 5B are schematic views for showing typical examples of air leakage occurring in the air cylinder, and show the relationship between the air leakage and the state of the piston.
As shown in FIG. 5A, when compressed air is supplied to the piston-side breathing hole 233, the rod of the air cylinder 200 comes out. On the other hand, as shown in FIG. 5 (b), when compressed air is supplied to the rod-side breathing hole 213, the rod of the air cylinder 200 is turned on.

In general, air leakage from an air cylinder often occurs due to wear or deterioration of the packing. In particular, the rod packing 211 that slidably rubs against the piston rod 210 that comes into contact with outside air containing dust and moisture is more likely to be worn and deteriorated than the piston packing 221.
When compressed air is supplied to the rod-side breathing hole 213 in a state where a minute gap 260 due to wear or deterioration is generated in the rod packing 211, an air leak 250 is generated in which the compressed air leaks to the outside. When air leakage from the minute gap 260 occurs, a sound 240 having a wide frequency spectrum from an audible range to an ultrasonic range is generated.

  On the other hand, when the air cylinder rod shown in FIG. 5 (a) is in the protruding state, the air leakage through which the compressed air leaks to the outside does not occur because the piston packing 221 is interposed. Therefore, in order to monitor the air leakage of the rod packing 211 that is easily worn or deteriorated, it is necessary for the monitoring device 20 to check the presence or absence of air leakage while the air cylinder rod is on.

  In the initial stage after the occurrence of air leakage, there is a correlation between the amount of air leakage generated from the minute gap 260 and the amplitude of the sound generated by the air leakage. The amplitude of the sound increases.

Example 1
Embodiment 1 of the present invention will be described below with reference to the drawings.
Here, a description will be given of a procedure in which the leakage monitoring system finds a leak and specifies the leaked air cylinder when one of the two air cylinders installed in the production apparatus has an air leak.

  FIG. 6 is a diagram schematically illustrating a part of the production apparatus according to the first embodiment. In the figure, 340 is a production apparatus, 300 is a microphone, 320 is an air cylinder A, and 330 is an air cylinder B. The air cylinder A320 and the air cylinder B330 are supplied with compressed air from a compressed air source (not shown) via a solenoid valve (not shown). The air cylinder A320 and the air cylinder B330 are connected to a control device (not shown), and the control device controls the operation of each air cylinder according to a control program that determines the operation and timing of the air cylinder. The air cylinder A320 and the air cylinder B330 can take two states of an exit state 322 and 332 and an entrance state 321 and 331, respectively.

  FIG. 7 is a time chart for explaining an operation sequence of the leakage monitoring system. The horizontal axis direction of each graph indicates the passage of time. The vertical axis of the microphone value graph indicates the output level of the microphone 300. The vertical axis of the cylinder A graph indicates whether the rod of the air cylinder A320 is in the out state 370 or the in state 371. Similarly, the vertical axis of the cylinder B graph indicates whether the rod of the air cylinder B330 is in the out state 380 or the in state 381. Further, the vertical axis of the determination graph indicates whether or not leakage of compressed air is detected.

In order to detect air leakage during the operation of each air cylinder based on the microphone value, as described above, it is necessary to confirm the presence or absence of air leakage while the air cylinder rod is on. The air cylinder A320 and the air cylinder B330 operate according to a predetermined control sequence. In this embodiment, the air cylinder A320 and the air cylinder B330 enter the ON state at different timings as shown in the time chart of FIG.
Therefore, at the timing when the air cylinder A is in the on state 371 and the timing when the air cylinder B is in the on state 381, the microphone value is compared with a predetermined threshold value 362 to determine the presence or absence of air leakage. That is, the microphone value 360 after passing from the microphone input 110 via the signal amplifier 120, the switch 121, and the AD converter 122 is compared with a preset threshold value 362 to obtain a determination result 390 for the presence or absence of leakage.

  In the example of FIG. 7, the determination result 390 is not detected 391 because the microphone value level is low in the air cylinder A entering state 371. On the other hand, in the air cylinder B entering state 381, the level of the microphone value exceeds the threshold value 362 as indicated by the dotted line 361, and therefore the determination result 390 becomes the detection 392. That is, the air device in which air leakage has occurred is identified as the air cylinder B.

  As described above, the leakage monitoring apparatus of the present embodiment can detect the presence or absence of air leakage from the information regarding the operation state of the air cylinder A320 and the air cylinder B330 of the production apparatus 340 and the detection result of the microphone. The air device can be identified. By performing monitoring processing on different operating states of a system including two air devices, it is possible to detect the presence or absence of air leakage for each air device even if only one microphone is provided.

(Example 2)
Embodiment 2 of the present invention will be described below with reference to the drawings.
In the second embodiment, in order to improve the detection accuracy, the amplification factor of the signal amplifier 120 is changed according to the type of air device to be operated. That is, among the two air cylinders A320 and B330 installed in the production apparatus 340, the microphone amplification factor is changed according to the air cylinder to be operated, and air leakage is detected with high sensitivity without erroneous detection.

  FIG. 8 is a time chart for explaining an operation sequence of the leakage monitoring system. The horizontal axis direction of each graph indicates the passage of time. The vertical axis of the amplification factor graph indicates the amplification factor of the signal amplifier 120. The vertical axis of the microphone value graph represents the level after amplification of the microphone 300. The vertical axis of the cylinder A graph indicates whether the rod of the air cylinder A320 is in the out state 470 or the in state 471. Similarly, the vertical axis of the cylinder B graph indicates whether the rod of the air cylinder B330 is in the out state 480 or the in state 481. Further, the vertical axis of the determination graph indicates whether or not leakage of compressed air is detected.

  In this embodiment, the air cylinder A320 is an air cylinder having a stroke greater than 50 mm and a piston diameter greater than 30 mm, and the air cylinder B330 is an air cylinder having a stroke of 50 mm or less and a piston diameter of 30 mm or less. The amplification factor b453 for the microphone signal of the air cylinder B330, which has a small cylinder volume and affects the operation with a small amount of air leakage, is set larger than the amplification factor for the microphone signal of the air cylinder A320. That is, b453> a452 in the gain graph of FIG.

  The leakage monitoring device acquires information regarding the operating states of the air cylinder A320 and the air cylinder B330 included in the production device 340 from the control device. Then, at the timing when the air cylinder A is in the on state 471, the amplification factor is set to a452 in order to prevent erroneous detection. In the case of the example in FIG. 8, the microphone value 460 after amplification does not exceed the threshold value 462, and therefore the determination 490 is not detected 491. On the other hand, at the timing when the air cylinder B330 is in the on state 481, the amplification factor is set to b453. At the timing when the air cylinder B330 is in the on state 481, the amplified microphone value 460 exceeds the threshold value 462, so the determination 490 becomes the detection 492.

  Thus, the leakage monitoring apparatus of the present embodiment can detect the air leakage with high sensitivity without false detection or oversight by setting the amplification factor of the microphone signal according to the type of the air device to be operated. If there is a leak, the air device can be identified. Even if only one microphone is provided, the presence or absence of air leakage can be detected for each air device by changing the amplification factor for different operating states of the system including different types of air devices. Can do.

(Example 3)
Embodiment 3 of the present invention will be described below with reference to the drawings.
In the third embodiment, a method for setting a threshold value for determining the presence or absence of air leakage occurring in an air device and an amplification factor of a microphone signal using a simulated leakage generator will be described.

  FIG. 9 is a diagram schematically illustrating a part of the production apparatus according to the third embodiment. In the figure, 340 is a production apparatus, 300 is a microphone, and 320 is an air cylinder A. The air cylinder A320 is supplied with compressed air from a compressed air source (not shown) via a solenoid valve (not shown). The air cylinder A320 is connected to a control device (not shown), and the control device controls the operation of each air cylinder according to a control program that determines the operation and timing. The air cylinder A320 can take two states, that is, an exiting state 322 and an entering state 321.

  Reference numeral 345 denotes a simulated leakage generator that can be said to be a feature of the present embodiment. The simulated leakage generating device 345 is a simulation device (speaker) that can simulate and generate sound generated by air leakage for each type of air cylinder. That is, the simulated leakage generator 345 stabilizes background sounds such as electrical operating sounds, mechanical operating sounds, normal compressed air flow sounds, and standard air leaking sounds according to the type of air cylinder. It is a device that can be generated.

FIG. 10 is a time chart for explaining a sequence for setting a threshold and an amplification factor in the leakage monitoring system of the present embodiment. The horizontal axis direction of each graph indicates the passage of time.
The simulated leakage generator 345 repeatedly generates the sound by changing the amplitude 400 (sound intensity) from the minimum amplitude 402 to the maximum amplitude 401 in order to simulate the state of the sound field according to the difference in the amount of air leakage.

  In this embodiment, the upper limit 421 of the microphone input target range is set according to the dynamic range and resolution of the AD converter 122 so that sound can be signal-processed with a sufficient S / N ratio in order to accurately detect the presence or absence of air leakage. And the lower limit 422 is determined. The amplification factor 410 is determined so that the maximum value 426 of the microphone value 420 and the upper limit 421 of the microphone input target range are the same, and the setting information is registered in the table 140 of the monitoring apparatus. In a state where the amplification factor is constant 411, the microphone value 427 when the microphone input target range is at least the lower limit 422 and the amplitude of the simulated leakage generator 345 is the minimum amplitude 402 is determined as the threshold value 423, and the signal intensity range 425 during normal operation is determined. . However, when the microphone value 424 is larger than the microphone value 427 at the time of the minimum amplitude 402 in the silent state 403, a value larger than the maximum value of the microphone value 424 in the silent state 403 is determined as the threshold value 423.

  In the present embodiment, a normal air device is replaced with an abnormal air device that causes a leak in order to set a threshold value for determining the presence or absence of air leak and an amplification factor of the microphone signal using the simulated leak generator. There is no need to experiment.

Example 4
Embodiment 4 of the present invention will be described below with reference to the drawings.
Here, a method of selecting which microphone to select in order to detect air leakage for a specific air device when a plurality of microphones are provided in the production apparatus will be described. In the present embodiment, microphones are installed in two places in the production apparatus, and a microphone having the highest signal intensity is appropriately selected from the two microphones.

  FIG. 11 is a schematic diagram of a production apparatus to which the present invention is applied. The production apparatus 340 is provided with a microphone A300, a microphone B301, and an air cylinder 320. For the air cylinder 320, a simulated leak generator 345 is installed in the vicinity of the target air cylinder 320 in order to select a microphone suitable for detecting air leak.

FIG. 12 is a time chart for explaining a sequence for selecting a microphone. The horizontal axis direction of each graph indicates the passage of time. First, a sound is generated from the simulated leak generator 345 by changing the amplitude 400 (sound intensity). First, the same minimum amplification factor is set for the microphone A300 and the microphone B301. When the sound generated from the simulated leakage generator 345 has the maximum amplitude 401, the maximum value 428 of the microphone value A420 is compared with the maximum value 429 of the microphone value B426, and the microphone closest to the upper limit 421 of the microphone input target range is selected. . However, if the maximum value 428 of the microphone value A420 and the maximum value 429 of the microphone value B426 are both lower than the lower limit 422 of the microphone input target range, the selection is performed again after increasing the amplification factor.
As in this embodiment, in a production apparatus having a plurality of microphones, the accuracy of air leakage detection can be improved by appropriately selecting a microphone with the highest signal intensity.

(Example 5)
Embodiment 5 of the present invention will be described below with reference to the drawings.
Here, the leakage monitoring in the case where an air cylinder and an air blow are installed in the production apparatus will be described. A description will be given of a procedure for generating an injection sound when the air blow operates normally and ejects compressed air, but prevents the injection sound from being erroneously detected as an abnormal air leak.

  FIG. 13 is a diagram schematically illustrating a part of the production apparatus according to the fifth embodiment. The production apparatus 540 is provided with a microphone 500, an air cylinder 520, and an air blow 530. The air cylinder 520 and the air blow 530 are connected to a control device (not shown) via a solenoid valve (not shown). The control device operates the air cylinder 520 and the air blow 530 in accordance with a control program that determines operation and timing. The air cylinder can take two states, an out state 522 and an in state 521. The air blow can take two states: an ON state 531 in which air is blown out, and an OFF state 532 in which no air is blown out.

FIG. 14 is a time chart for explaining the switching sequence of the monitoring operation so as not to misidentify the normal operation of air blow as air leakage in the leakage monitoring system of the present embodiment. The horizontal axis direction of each graph indicates the passage of time.
The leakage monitoring system of this embodiment monitors air leakage due to wear and deterioration of the rod side packing that is easily worn in the air cylinder. Therefore, monitoring is performed at the timing when the air cylinder is in the on state 571 (551). In the example of FIG. 14, even if the air cylinder shifts from the exiting state 570 to the entering state 571, the microphone value 560 does not exceed the threshold value 562, so the determination 590 is not detected 591 and air leakage occurs. It can be judged that it is not. On the other hand, when the air blow shifts from the OFF state 580 to the ON state 581, compressed air is discharged from the air blow 530, and thus an air leakage sound is generated. Therefore, even if the air blow 530 operates normally, the microphone value exceeds the threshold value 562 (561).

  The leakage monitoring apparatus according to the present embodiment turns on the monitoring of the air cylinder entering state (551) in light of the information on the operating state of the air cylinder 520 and the air blow 530 of the production apparatus 540, and the air blow operating noise is generated. At timing, monitoring is turned off (550). Since the microphone value 560 is not monitored when the air blow 530 is in the ON state 581 by the monitoring switching 550, the determination is “not detected” 592. Since it is possible to monitor only the state of the air cylinder that is likely to cause air leakage by monitoring switching, it is possible to prevent erroneous detection.

  If there is a device in the device that generates a sound similar to the sound caused by air leakage during normal operation, such as an air blow, the timely monitoring operation can be switched off in light of the information on the operation status. , False detection can be prevented. In addition to air blow, devices that generate a sound confusing with air leakage even under normal operation include a vacuum adsorber, a static eliminator, and an ultrasonic welder.

(Example 6)
Embodiment 6 of the present invention will be described below with reference to the drawings.
Here, when an air cylinder and an air blow are installed in the production device, not only the presence of air leakage in the air cylinder is monitored using a microphone, but also whether the air blow is operating normally is detected. How to do will be described.

  FIG. 15 is a time chart for explaining an operation sequence of the leakage monitoring system. The horizontal axis direction of each graph indicates the passage of time. Here, the air cylinder 520 shown in FIG. 13 operates normally without leakage, but the case where the air blow 530 does not operate normally will be described as an example.

  First, when the air cylinder shifts from the out state 570 to the on state 571, the microphone value 560 does not exceed the threshold value 562, so the determination 590 is not detected 591 and it is determined that no air leakage has occurred. To do. On the other hand, when the air blow changes from the OFF state 580 to the ON state 581, the air blow becomes abnormal and air injection becomes insufficient, and the microphone value 561 does not exceed the threshold value 562. The leak monitoring system determines that the air blow is not operating normally from the information regarding the operating state of the air blow and the detection result of the microphone, because the microphone value does not exceed the threshold value 562 regardless of the state in which the air blow should operate.

  In the present embodiment, in addition to monitoring the presence or absence of air leakage in an air cylinder or the like, it is possible to detect whether or not a device that generates air flow noise during operation, such as air blow, is operating normally. In addition to air blow, devices that generate air flow noise during normal operation include vacuum adsorbers, static eliminators, and ultrasonic welders.

(Example 7)
Embodiment 7 of the present invention will be described below with reference to the drawings.
In this embodiment, the leakage monitoring system acquires information on the operating state from a control device that controls peripheral production apparatuses, thereby preventing the occurrence of false detection due to the influence of the operation of the peripheral production apparatuses.

  FIG. 16 shows a schematic diagram of the production system of the present embodiment. In the figure, reference numeral 625 denotes a production apparatus A included in the production system, reference numeral 635 denotes a production apparatus B also included in the production system, and the production apparatus A 625 and the production apparatus B 635 are adjacent to each other.

An air blow 610 in the production apparatus A 625 is connected to a control device 645 that controls the production apparatus A 625 via an electromagnetic valve 647. A leakage monitoring device A640 that monitors leakage of the production device A625 is connected to the control device 645 and the microphone 600. The leakage monitoring apparatus A 640 and the control apparatus 645 are connected to the factory network 649.
Further, the vacuum adsorber 630 in the production apparatus B635 is connected via a solenoid valve 648 to a control device 646 that controls the production apparatus B635. A leakage monitoring device B 641 for monitoring leakage of the production device B 635 is connected to the control device 646 and the microphone 601. The leakage monitoring device B 641 and the control device 646 are connected to the factory network 649.

  The air blow 610 in the production apparatus A 625 and the vacuum suction unit 630 in the production apparatus B 635 generate an air leakage sound during normal operation. Since the production apparatus A 625 and the production apparatus B 635 are adjacent to each other, the microphone A 600 in the production apparatus A 625 is affected by an air leakage sound caused by the normal operation of the vacuum suction device 630 in the production apparatus B 635. Similarly, the microphone B601 in the production apparatus B635 is affected by an air leakage sound due to the normal operation of the air blow 610 in the production apparatus A625.

FIGS. 17A and 17B are time charts for explaining the operation sequence of the leakage monitoring system. The horizontal axis direction of each graph indicates the passage of time.
FIG. 17A is a time chart showing an operation sequence of the leakage monitoring system on the production apparatus A 625 side. When the air blow 610 is in the ON state 671, the microphone value A661 exceeds the threshold value 663. As described in the sixth embodiment, the air blow generates an air leakage sound during normal operation, so that the determination A690 is determined to be normal and the detection 691 is not detected.

  On the other hand, when the vacuum suction device 630 in the production apparatus B635 is turned on 681, an air leakage sound is generated even in normal operation, and the microphone value A662 exceeds the threshold value 663. In order to prevent erroneous detection that the vacuum adsorber 630 is operating normally as an air leak, the leak monitoring device A 640 receives information on the operating status of the vacuum adsorber 630 from the control device 646 via the factory network. get. Leakage monitoring apparatus A640 turns off monitoring without performing threshold judgment during a period in which vacuum suction device 630 is in the ON state 681 by monitoring switching A650. Therefore, even if the microphone value A660 exceeds the threshold value 663 due to the operation sound generated by the vacuum suction device 630, the determination A690 of the leakage monitoring device A640 is not detected 692, and no erroneous detection occurs.

  FIG. 17B is a time chart showing an operation sequence of the leakage monitoring system on the production apparatus B635 side. When the air blow 610 in the production apparatus A 625 is in the ON state 671, an air leakage sound is generated even if the air blow is operating normally, and the microphone value B666 exceeds the threshold value 668. In order to prevent erroneous detection due to the operation sound of the air blow 610, the leakage monitoring device B 641 acquires information on the operating state of the air blow from the control device 645. Leakage monitoring apparatus B641 turns off monitoring without performing threshold determination during period when air blow 610 is in the ON state 671 by monitoring switching B652. Therefore, even if the microphone value B665 exceeds the threshold value 668 due to the operation sound generated by the air blow 610, the determination B695 of the leakage monitoring device B641 is not detected 696, and no erroneous detection occurs. On the other hand, when the vacuum suction device 630 is in the ON state 681, the microphone value B667 exceeds the threshold value 668 in normal operation, and therefore the determination B695 is determined to be normal and the detection is undetected 697.

  In this embodiment, the leak monitoring device acquires information on the operating state from the surrounding control device via the network, thereby preventing false detection even when the air leak sound is generated from the surrounding air device. Can do.

[Other embodiments]
The embodiments of the present invention are not limited to the above-described Embodiments 1 to 7, and can be appropriately changed or combined.
For example, when determining the presence or absence of air leakage, it does not necessarily have to be determined by whether or not the threshold value is exceeded. For example, an upper limit and a lower limit may be set, and determination may be made based on whether or not the signal level is within a predetermined range.
Moreover, the microphone to be used is not limited as long as it can detect ultrasonic waves, and may be a microphone having sensitivity in an audible range.
Further, with respect to a signal input from a microphone, a frequency band that is not suitable for air leakage detection may be cut by a filter, or only an ultrasonic frequency band may be amplified.

  10, 11, 12 ... Mic / 20, 21, 22 ... Monitoring device / 30,31,32 ... Control device / 45,46,47 ... Air equipment / 50,51,53,54 56, 57 ... Air cylinder / 52 ... Vacuum suction device / 55 ... Air blow / 70, 71, 72 ... Production equipment / 73 ... Production line / 90, 91 ... Network / 110 ... Microphone input / 120 ... Signal amplifier / 121 ... Switch / 122 ... AD converter / 160 ... Comparator / 200 ... Air cylinder / 210 ... Piston rod / 211 ... Rod packing / 220 ... Piston / 221 ... Piston packing / 250 ... Air leakage

Claims (10)

A plurality of pneumatic devices that operate in response to the supply of compressed air;
A microphone capable of detecting ultrasound,
A control unit,
The controller is
Acquire in advance information of a plurality of air leak detection reference values set corresponding to different operation states included in the operation sequence of the plurality of air devices,
Comparing an arbitrary air leak detection reference value among the plurality of air leak detection reference values and a signal input from the microphone in an operation state corresponding to the air leak detection reference value,
When the signal input from the microphone exceeds the air leak detection reference value, the air device in which the air leak has occurred is identified based on the operating state of the plurality of air devices corresponding to the air leak detection reference value. To
Leakage monitoring system for monitoring a plurality of air devices. The plurality of air devices include an air cylinder, and the air leak detection reference value is set corresponding to an operation state in which a cylinder rod is inserted.
The leakage monitoring system according to claim 1. The control unit amplifies the signal input from the microphone with an amplifier whose amplification factor can be changed according to the operating state of the plurality of air devices, and then compares the signal with the air leak detection reference value.
The leakage monitoring system according to claim 1 or 2, wherein The control unit operates a simulation device that simulates sound when air leakage occurs in the air device, and acquires information on the air leakage detection reference value in advance.
The leak monitoring system according to any one of claims 1 to 3, wherein The control unit operates a simulation device that simulates sound when air leakage occurs in the air device, and sets the amplification factor of the amplifier.
The leakage monitoring system according to claim 3. The leakage monitoring system includes a plurality of the microphones,
The control unit selects a signal input from a microphone having the largest signal intensity from the plurality of microphones according to an operation state of the plurality of air devices, and compares the selected signal with the air leak detection reference value.
The leakage monitoring system according to any one of claims 1 to 5, wherein the leakage monitoring system is characterized in that: The control unit does not monitor air leakage based on a signal input from the microphone in an operating state in which an air device that blows out compressed air during normal operation operates.
The leakage monitoring system according to any one of claims 1 to 6, wherein the leakage monitoring system is characterized in that: The control unit detects whether or not the air device that ejects the compressed air is operating normally based on a signal input from the microphone in an operating state in which the air device that ejects the compressed air during normal operation operates. To
The leakage monitoring system according to claim 7. A production apparatus comprising a plurality of pneumatic devices that operate in response to supply of compressed air;
A microphone capable of detecting ultrasound,
A production system having a control unit,
The controller is
Acquire in advance information of a plurality of air leak detection reference values set corresponding to different operating states of the plurality of air devices included in the operation sequence of the production apparatus,
Comparing an arbitrary air leak detection reference value among the plurality of air leak detection reference values and a signal input from the microphone in an operation state corresponding to the air leak detection reference value,
When the signal input from the microphone exceeds the air leak detection reference value, the air device in which the air leak has occurred is identified based on the operating state of the plurality of air devices corresponding to the air leak detection reference value. To
A production system characterized by that. A production apparatus comprising a plurality of pneumatic devices that operate in response to supply of compressed air;
A microphone capable of detecting ultrasound,
A manufacturing method of an article using a production system having a control unit,
The controller is
Acquire in advance information of a plurality of air leak detection reference values set corresponding to different operating states of the plurality of air devices included in the operation sequence of the production apparatus,
An arbitrary air leak detection reference value among the plurality of air leak detection reference values is compared with a signal input from the microphone in an operation state corresponding to the air leak detection reference value at the time of manufacturing an article. ,
When the signal input from the microphone exceeds the air leak detection reference value, the air device in which the air leak has occurred is identified based on the operating state of the plurality of air devices corresponding to the air leak detection reference value. To
A method for manufacturing an article.

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