JP2022015508A - Maintenance period determination system - Google Patents

Abstract

To provide a new maintenance determination device for, without erroneous detection, determining a maintenance period of a consumable article and oil or the like in a manufacturing line.SOLUTION: A maintenance period determination system 1 includes a generation time detection section 2, a generation frequency detection section 3, and a discrimination section 4. The generation time detection section 2 counts generation times of a warning signal detected by an abnormality detection sensor 6 within a predetermined first unit time. The generation frequency detection section 3 counts generation times of a warning signal detected within a second unit time which is obtained by dividing the first unit time into smaller unit times. The discrimination section 4 outputs a maintenance period discrimination result when a first state occurs where the generation times of a warning signal detected within the first unit time become equal to or more than the first times, and also when a second state occurs where the generation times of a warning signal detected within the second unit time become equal to or more than the second times, or when a third state occurs where the generation times of a warning signal detected within the respectively continuous second unit times become equal to or more than the third times.SELECTED DRAWING: Figure 1

Description

The present invention relates to a maintenance timing determination system for various parts such as a production line.

In a general production line, various sensors are used to detect abnormalities. For example, in Patent Document 1, an abnormality is detected by using an acoustic / vibration sensor that analyzes sounds and vibrations generated from a production line and determines an abnormality based on a frequency spectrum. In these production lines, consumable parts, oil, etc. are always present, and the maintenance time is checked with a sensor. Further, in [0013] to [0014] of Patent Document 2, an acoustic / vibration sensor for detecting an acoustic caused by running out of oil is used in order to know the maintenance time such as lubrication.

International Publication No. 2006/043511 Japanese Unexamined Patent Publication No. 9-260465

However, it is difficult to detect rust and running out of oil using an acoustic / vibration sensor. For example, when a tooth of a gear has a flaw, a peculiar sound / vibration occurs when the tooth with the flaw meshes with the tooth of another gear corresponding to the rotation speed of the rotating shaft. Synchronized with the rotation speed of the gear. However, in the case of rust or running out of lubricating oil (hereinafter referred to as "running out of oil"), such a cycle may not be captured, and when the sound of a frequency different from the frequency of the sound emitted at normal times is output, the oil runs out. It is described in Patent Document 2 [0014] that the determination is made. However, if the oil runs out completely and it becomes a fatal state, it is difficult to detect the sound and vibration that are signs of running out of oil separately from the noise. In addition, erroneous detection is likely to occur due to unrelated sound / vibration such as when a loud noise is heard nearby.
It is possible to improve the accuracy to prevent false positives and to provide a compensation mechanism, but it is costly and it is difficult to completely prevent false positives.
Therefore, the judgment of the maintenance time had to rely on the experience of the worker who operates the production line.

Therefore, it is an object of the present invention to provide a new maintenance time determination system.

In order to solve such a problem, the present invention includes an occurrence number detection unit, an occurrence frequency detection unit, and a discrimination unit, and the occurrence number detection unit is an alarm detected by a sensor within a predetermined first unit time. The number of occurrences of the signal is counted, and the occurrence frequency detection unit counts the number of occurrences of the alarm signal detected within the second unit time obtained by dividing the first unit time into smaller unit times, and determines the determination. The unit is a case where the first state occurs in which the number of occurrences of the alarm signal detected within the first unit time is equal to or greater than the first number of times, and (1) the second unit time. The second state in which the number of occurrences of the alarm signal detected within is equal to or greater than the second number, or (2) the number of occurrences of the alarm signal detected within each consecutive second unit time. However, the maintenance timing determination system is characterized in that the maintenance timing determination result is output when a third state occurs in which the number of times is equal to or greater than the third.

It is now possible to determine the maintenance time.

Overall configuration diagram of the embodiment Explanatory diagram of the number of occurrences of the alarm signal of the embodiment (A) Graph of the number of occurrences detected in the first unit time (B) Graph of the number of occurrences detected in the second unit time

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts having the same function, and duplicate description in each figure will be omitted as appropriate.

(Example)
An embodiment is a maintenance time determination system 1 relating to a power transmission system 7 using an acoustic / vibration sensor 6 as an abnormality detection sensor. Since the production line usually has various power transmission systems 7, a large number of acoustic / vibration sensors 6 (abnormality detection sensors) are provided, and each of them independently monitors a predetermined power transmission system 7.
FIG. 1 is an overall configuration diagram of an embodiment. An acoustic / vibration sensor 6 (abnormality detection sensor) is provided at an appropriate position in the power transmission system 7. From the acoustic vibration sensor 6 (abnormality detection sensor), the acoustic / vibration data 61 is always sent to the analysis unit 63. The analysis unit 63 analyzes the acoustic / vibration data 61, and in the embodiment, the frequency and the power spectral density are analyzed by the short-time FFT. The analysis in the analysis unit 63 is not limited to the FFT, and an orthogonal transformation for analyzing the frequency and period such as a wavelet transformation may be used. The analysis unit 63 has input in advance a frequency at which a failure or the possibility of failure can be detected, and outputs an alarm signal 631 to the alarm unit 62 when the power spectral density value of the frequency or period becomes equal to or higher than a threshold value. For example, when the tooth of the gear 71 is scratched, sound or vibration is generated in each rotation cycle of the gear, and by detecting the cycle together with the frequency of the sound, it is possible to detect which gear has an abnormality. Further, in the case of a bearing defect, sound and vibration occur at a cycle peculiar to each component constituting the bearing such as a ball, an inner ring, and an outer ring.

These detections are also made by general acoustic and vibration analysis.
Hereinafter, in order to avoid confusion, the warning signal 631 regarding the detection result indicating the sign of running out of oil sent to the maintenance time determination system 1 is referred to as "oil running out warning signal 6311", and the warning signal based on other troubles is distinguished as "631". I will do it.
The signs of running out of oil, which are the targets of the examples, often do not have a specific period or frequency. For example, the cycle and frequency differ depending on which gear 71 of the power transmission system 7 is out of oil, and further, the cycle and frequency also differ depending on the rotation speed at that time. Therefore, the analysis unit 63 of the embodiment produces sound having a frequency or period different from the frequency of the sound emitted at normal times, which is sound / vibration other than the frequency or period generated by other causes input in advance. It has come to judge when there is a sign of running out of oil. Then, the maintenance time determination system 1 receives only the oil shortage warning signal 6311 sent from the analysis unit 63. The analysis unit 63 may be set so that the alarm signal 631 other than the oil shortage, for example, the alarm signal 631 when a defect occurs in a predetermined gear, is not sent to the maintenance time determination system.

Conventionally, when the analysis unit 63 of the sound / vibration sensor 6 (abnormality detection sensor) detects a sign of oil shortage, the analysis unit 63 sends an oil shortage warning signal 6311 to the alarm unit 62 and also sends an alarm signal 631 to the production line control device 8. Feed and stop the production line. As described above, it is difficult to detect out of oil, and an operator who receives an alarm of out of oil often presses the restart button 81 without confirming that there is a high possibility of erroneous detection to restart. Repeated restarts like this will eventually lead to major troubles, and the production line will have to be overhauled on a large scale.
In the maintenance time determination system 1 of the embodiment, the production line is not stopped and the alarm unit 62 does not issue an alarm just because the oil shortage alarm signal 6311 indicating a sign of oil shortage is output from the analysis unit 63. It is also possible to do.
The maintenance time determination system 1 of the embodiment can be additionally provided to the analysis unit 63 of the existing production line.

(Outline of maintenance time judgment system)
The maintenance time determination system 1 includes (1) occurrence frequency detection unit 2, (2) occurrence frequency detection unit 3, (3) determination unit 4, and (4) notification unit 5. These functions will be described in order. In addition, (1) to (4) in the present invention may be a device or a component having a substance, or may be a module on software. Further, it may be mounted on one device, or may be connected to those distributed on the network and virtually exist as the maintenance time determination system 1. Any form is acceptable as long as it has the function of the maintenance time determination system 1 according to the present invention.

(Number of occurrence detection unit)
The oil shortage warning signal 6311 sent from the analysis unit 63 is sent to the occurrence frequency detection unit 2. Then, when the sent oil shortage warning signal 6311 is input, the occurrence number detection unit 2 counts the number of occurrences of the oil shortage warning signal 6311 detected within the predetermined first unit time t1 and totals them. Calculate the number. FIG. 2 is an explanatory diagram of the number of occurrences of the oil shortage warning signal 6311 of the embodiment, and FIG. 2A is a graph of the number of occurrences detected in the first unit time t1 created for explanation. .. The vertical axis represents the number of occurrences of the oil shortage warning signal 6311 generated within the first unit time t1, and the horizontal axis indicates the time in which the unit time t1 is used.
The first unit time t1 is appropriately determined according to the object to be measured. The power transmission system 7 that rotates at a relatively high speed is set short, and the power transmission system 7 that rotates slowly is set long.

(Occurrence frequency detection unit)
The alarm signal 631 sent from the analysis unit 63 is sent to the occurrence frequency detection unit 3. In FIG. 1, it is shown that the oil shortage warning signal 6311 is directly sent from the analysis unit 63, but the oil shortage warning signal 6311 may be sent via the occurrence frequency detection unit 2, resulting in the oil shortage warning signal 6311. If the occurrence frequency detection unit 3 functions, the oil shortage warning signal 6311 may be sent to the occurrence frequency detection unit 3.

FIG. 2B is a graph of the number of occurrences detected in the second unit time t2 created for explanation. The vertical axis is the number of occurrences of the oil shortage warning signal 6311, and the horizontal axis is the time in which the second unit time t2 obtained by dividing the first unit time t1 into smaller unit times is used as a unit. In FIG. 2B, the first unit time t1 divided into 18 is referred to as the second unit time t2.
How to set the second unit time t2 is appropriate. The occurrence frequency detection unit 3 counts the number of occurrences of the oil shortage warning signal 6311 received within the second unit time t2.

(Discrimination section)
As shown in FIG. 1, the discriminating unit 4 receives information on the number of occurrences of the oil shortage warning signal 6311 detected within the first unit time t1 sent from the occurrence frequency detection unit 2, and also receives the occurrence frequency detection unit 3. Receives information on the number of occurrences detected within the second unit time t2 sent from.
As shown in FIG. 2A, the discriminating unit 4 determines whether or not the number of occurrences of the first number 42 or more is detected within the first unit time t1 with the first number 42 as the threshold value. The case where the number of occurrences of the first occurrence number 42 or more is detected is referred to as "first state 45". In FIG. 2A, the case where the number of occurrences is the first state 45 is detected twice.
Then, when the first state 45 is detected, the analysis proceeds to the analysis shown in FIG. 2 (B). Since it is determined at the time when the first unit time t1 is completed whether or not the first state 45 is reached, the analysis shown in FIG. 2 (B) below in the embodiment is based on the first unit time t1. Starts after the end. This is because the maintenance time determination system 1 does not notify that a dangerous state has occurred, but determines and notifies the maintenance time, and the determination in the first unit time t1 unit is sufficient.
Of course, it does not prevent the analysis shown in FIG. 2B from moving to the time when the first state exceeding the first occurrence frequency 42 is detected before the end of the first unit time t1.

The determination unit 4 determines whether or not the second state 46 is such that the number of occurrences of the oil shortage warning signal 6311 detected within the second unit time t2 is 43 or more of the second number of times 43. When the discrimination unit 4 determines that the second state 46 has been reached, the discrimination unit 4 outputs the discrimination result 41 to the notification unit 5. The fact that a large number of oil shortage warning signals 6311 exceeding the second number of times 43 are generated in a short time of the second unit time t2 is because there is a high possibility that maintenance is required rather than false detection. Even if it is caused by some kind of false detection, it is better for the operator to check the power transmission system 7 for confirmation. If there are too many false positives, the worker can deal with it by increasing the second number of times 43.

Further, in the discrimination unit 4, has the third state 47 in which the number of occurrences of the oil shortage warning signal 6311 detected within each consecutive second unit time t2 is 44 or more in the third number of times 44 or more? Judge whether or not. Each continuous second unit time t2 corresponds to an adjacent second unit time t2 in the graph of FIG. 2 (B). The third state 47 in which the number of times of the oil shortage warning signal 6311 having a third number of times 44 or more is detected in each consecutive second unit time t2 is shown in FIG. 2 (B). In such a case, the discrimination unit 4 outputs the discrimination result 41 to the notification unit 5.
The fact that the third state 47 is reached in each of the continuous second unit times t2 indicates that there is a high possibility that the oil shortage warning signal 6311 is constantly generated, and it is also a false detection or the like. This is because it is necessary to check for maintenance.

Summarizing the above description of the discriminating unit 4, first, in the discriminating unit 4, the number of occurrences of the oil shortage warning signal 6311 detected within the first unit time t1 is 42 or more as the first number of times 42 or more. It is determined whether or not the state 45 has occurred.
Then, only when the first state 45 is reached, the following two judgments are made.
(1) The discriminating unit 4 determines whether or not a second state 46 has occurred in which the number of occurrences of the oil shortage warning signal 6311 detected within the second unit time t2 is 43 or more of the second number of occurrences. ..
(2) It is determined whether or not a third state 47 has occurred in which the number of occurrences of the oil shortage warning signal 6311 detected within each consecutive second unit time t2 is 44 or more of the third number of times. do.
Then, the discrimination unit 4 outputs the discrimination result 41 to the notification unit 5 when the first state 45 occurs and the second state 46 of (1) is reached.
Further, the discrimination unit 4 outputs the discrimination result 41 to the notification unit 5 when the first state 45 occurs and the third state 47 of (2) is reached.

As described above, the analysis unit 63 has come to determine that there is a sign of running out of oil when a sound with a frequency or period different from the frequency of the sound emitted at normal times is output, but there is a sign of running out of oil. It is also possible to lower the threshold for issuing the oil shortage warning signal 6311 indicating that the oil shortage warning signal 6311 is issued frequently. By doing so, it is not possible to overlook the sound / vibration that is a sign of running out of oil, which is difficult to detect. Even if the oil shortage warning signal 6311 is frequently output from the analysis unit 63, the determination unit 4 of the maintenance time determination system 1 separately determines the sign of oil shortage and determines whether or not the maintenance time has come. The person is not bothered by the oil shortage warning signal 6311 that is frequently generated. Even if the analysis unit 63 outputs an oil shortage alarm signal 6311 indicating a sign of oil shortage, it is not necessary to stop the production line via the production line control device 8 and the alarm unit 62 does not issue an oil shortage alarm. You can also do it.

(Notification unit)
The notification unit 5 receives the discrimination result 41 from the discrimination unit 4 and performs notification. The method of notification is arbitrary, and notification is performed by a method suitable for the work place, such as displaying on a display or notifying by voice.

As described above, in the embodiment, the occurrence frequency detection unit 2 and the occurrence frequency detection unit 3 have been described separately. However, the occurrence frequency detection unit 2 and the occurrence frequency detection unit 3 are the same in that they both count the number of times of the oil shortage warning signal 6311, and the unit time is the first unit time t1 and the second unit time t2. It's just different. Therefore, the occurrence frequency detection unit 2 and the occurrence frequency detection unit 3 can be integrated into one, which is also included in the present invention.
Further, as described above, the main parts of the occurrence frequency detection unit 2, the occurrence frequency detection unit 3, the discrimination unit 4, and the notification unit 5 may be modules on software, and software that integrates these may be used. Needless to say, the incorporated device may be used as the maintenance time determination system 1.

Further, although the description in the examples relates to the sign of running out of oil, the present invention can be applied to all sensors and detection objects such as sensors that are prone to false detection.
As shown in the examples, we were able to provide a new maintenance time determination system.

Further, the maintenance time determination system 1 of the present invention can be mounted on various devices such as a production line.

Although the examples according to the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the design does not deviate from the gist of the present invention. Even if there is a change or the like, it is included in the present invention.
Further, the above-mentioned examples and modifications can be combined by diverting the technologies of each other as long as there is no particular contradiction or problem in the purpose and configuration thereof.

1 Maintenance time determination system 2 Occurrence frequency detection unit 3 Occurrence frequency detection unit 4 Discrimination unit 41 Discrimination result 42 First number of times 43 Second number of times 44 Third number of times 45 First state 46 Second state 47 Third state Status 5 Notification unit 6 Sound / vibration sensor (abnormality detection sensor)
61 Sound / vibration data 62 Alarm unit 63 Analysis unit 631 Alarm signal 6311 Oil shortage alarm signal 7 Power transmission system 71 Gear 8 Manufacturing line controller 81 Restart button t1 First unit time t2 Second unit time

Claims (1)

Equipped with an occurrence frequency detection unit, an occurrence frequency detection unit, and a discrimination unit
The occurrence number detection unit counts the number of occurrences of the alarm signal detected by the abnormality detection sensor within a predetermined first unit time, and counts the number of occurrences.
The occurrence frequency detection unit counts the number of occurrences of the alarm signal detected within the second unit time obtained by dividing the first unit time into smaller unit times.
The discrimination unit is
When the first state occurs in which the number of occurrences of the alarm signal detected within the first unit time is equal to or greater than the first number of times, and
(1) A second state in which the number of occurrences of the alarm signal detected within the second unit time is equal to or greater than the second number.
or,
(2) When a third state occurs in which the number of occurrences of the alarm signal detected within each of the consecutive second unit times is equal to or greater than the third number, the maintenance time determination result is determined. A maintenance time determination system characterized by outputting.

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