Unbalance measuring device, unbalance measuring method, and unbalance measuring program

Abstract

This imbalance measurement device 10 comprises: a measurement mechanism 11 that measures the amount of imbalance in a workpiece W that has undergone a prescribed manufacturing step; and an abnormality detection unit 12 that, in cases in which the amount of imbalance exceeds a prescribed range established in advance, outputs abnormality detection data indicating that an abnormality has occurred.

Description

Technical Field

[0001] The present invention relates to an imbalance measuring device for measuring the amount of imbalance of a workpiece and the like.

Background Art

[0002] Conventionally, an operation has been performed in which the amount of imbalance of each workpiece that has undergone a predetermined manufacturing process is measured, and the workpiece is corrected based on the amount of imbalance.

[0003] And for the measurement of the imbalance, as described in Patent Document 1, an imbalance measuring device that detects vibration when the workpiece is rotated and calculates the amount of imbalance of the workpiece based on the detected vibration is used.

[0004] However, for example, if an abnormality occurs in the manufacturing process before the measurement stage, workpieces that have undergone the abnormal process will be continuously manufactured. And if the correction processing of such workpieces is performed based on the amount of imbalance of the workpieces, a situation may occur where a large imbalance correction has to be performed for each workpiece one by one, that is, a situation where the imbalance correction time and the number of corrections increase, and it may also lead to a fatal defect in the manufacturing process itself.

[0005] Also, if the imbalance correction time and the number of corrections increase too much, it may be difficult to ensure the final quality of the workpiece.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] This invention is the first to focus on detecting abnormalities in the manufacturing process based on the measured amount of imbalance, and aims to detect the aforementioned problems in the manufacturing process as far in advance as possible, thereby ensuring its integrity and, consequently, the quality of the workpiece. [Means for solving the problem]

[0008] In other words, the unbalance measuring device according to the present invention is characterized by comprising: a measuring mechanism for measuring the amount of unbalance of a workpiece that has undergone a predetermined manufacturing process; and an abnormality detection unit that detects an abnormality in the predetermined manufacturing process based on the amount of unbalance measured by the measuring mechanism and outputs abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process. [Effects of the Invention]

[0009] With this configuration, the output of the anomaly detection data will reliably inform the user that an unexpectedly unbalanced amount of workpieces is being manufactured, prompting them to check for any possible malfunctions in the preceding manufacturing process. As a result, the manufacturing process can be made more efficient, and ultimately, the quality of the workpiece can be guaranteed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an unbalance measuring device according to one embodiment of the present invention. [Figure 2] (a) A schematic diagram of the display unit in a normal state, and (b) A schematic diagram of the display unit in an abnormal state, according to one embodiment of the present invention. [Figure 3] This is a flowchart of the unbalance measurement method in one embodiment of the present invention. [Modes for carrying out the invention]

[0011] An embodiment of the unbalance measuring device according to the present invention will be described below with reference to the drawings. Note that, for the sake of clarity, some figures shown below may be simplified or exaggerated for illustrative purposes. The same reference numerals are used for identical components, and their descriptions will be omitted as appropriate.

[0012] <1.Device configuration> In this embodiment, the unbalance measuring device 10 performs unbalance measurement on a workpiece W that has undergone a predetermined manufacturing process, such as cutting, plating, or machining. After being measured by the unbalance measuring device 10, the workpiece W is sent to an unbalance correction device 20 that corrects the unbalance of the workpiece W. In this embodiment, the unbalance measuring device 10 and the unbalance correction device 20 constitute the unbalance correction system 100. The workpiece W is a rotating body, such as a rotor, and has a long, columnar shape.

[0013] The unbalance measuring device 10 comprises a measuring mechanism 11 for measuring the amount of unbalance of the workpiece W, an abnormality detection unit 12 for detecting abnormalities based on the amount of unbalance of the workpiece W, a state data storage unit 13 for storing state data which is data indicating the state of the measuring mechanism 11, and a display unit 14 for displaying the amount of unbalance of the workpiece W and any abnormalities. The following describes each part of the unbalance measuring device 10.

[0014] The measuring mechanism 11 includes bearings 111 on which the axial ends of the workpiece W are supported, a spring 112 that supports the bearings 111 so as to be displaceable, a belt 113 stretched in the circumferential direction of the workpiece W, a motor 114 that rotates the belt 113 by driving, a sensor unit 115 that detects vibration of the bearings 111 and rotation of the workpiece W, and an unbalance amount calculation unit 116 that calculates the amount of unbalance of the workpiece W based on the signal output by the sensor unit 115.

[0015] If there is an imbalance in the workpiece W, the bearing 111 vibrates as the workpiece W rotates, so the sensor unit 115 detects the rotation of the workpiece W and the vibration of the bearing 111. In this embodiment, the sensor unit 115 includes a rotation detection sensor 115a that detects the rotation of the workpiece W and a vibration detection sensor 115b that detects the vibration of the bearing 111.

[0016] The rotation detection sensor 115a is positioned close to a mark M attached to the outer circumferential surface of the workpiece W. When the workpiece W rotates, the rotation detection sensor 115a detects the mark M and outputs a signal with the time of detection of the mark M as the phase reference.

[0017] The vibration detection sensor 115b is a moving coil type, provided for each bearing 111. Specifically, when each bearing 111 vibrates due to the rotation of the workpiece W, the vibration detection sensor 115b detects the displacement of each bearing 111 and outputs a sinusoidal signal corresponding to that displacement.

[0018] The unbalance amount calculation unit 116 calculates the unbalance amount of the workpiece W based on the signals output by each sensor. The unbalance amount calculation unit 116 is provided in a computing device that is composed of a so-called computer equipped with a CPU, memory, input / output means, etc.

[0019] In this embodiment, the unbalance amount is a multi-dimensional value consisting of the magnitude of vibration on the left and right sides of the workpiece W, the phase angle which indicates the angular difference between the maximum value of vibration on the left and right sides of the workpiece W and the phase reference, and so on. The unbalance amount calculation unit 116 calculates the magnitude of vibration on the left and right sides of the workpiece W from the amplitude values ​​of the signals output by each vibration detection sensor 115b. The unbalance amount calculation unit 116 also calculates the phase angle of each left and right side from the phase relationship of the signal from the rotation detection sensor 115a and the signals from each vibration detection sensor 115b.

[0020] The abnormality detection unit 12 detects an abnormality in a predetermined manufacturing process based on the amount of imbalance. Specifically, the abnormality detection unit 12 determines whether the amount of imbalance exceeds a predetermined range, and if it is determined that the amount exceeds the predetermined range, the abnormality detection unit 12 outputs abnormality detection data indicating that an abnormality has occurred in the manufacturing process. The abnormality detection unit 12 outputs abnormality detection data only for the workpiece W before the imbalance correction is performed, for example. Physically, the abnormality detection unit 12 is provided in an arithmetic device configured by a so-called computer including a CPU, a memory, input / output means, and the like.

[0021] The predetermined range of the amount of imbalance described above is determined in advance based on statistical data indicating the statistics of the amounts of imbalance of a plurality of workpieces of the same type, and its value is stored in a predetermined area of the memory. Specifically, the statistical data is the measured values of the amounts of imbalance of a plurality of workpieces W of the same type, the average value μ of the amounts of imbalance of those workpieces W, and the standard deviation σ of the amounts of imbalance of those workpieces W, and these are also stored in the memory. In the present embodiment, a Shewhart control chart created from the above statistical data is stored in the same memory. The Shewhart control chart has the average value μ as the center line, and using the average value μ and the standard deviation σ, μ + 3σ is the upper control limit line and μ - 3σ is the lower control limit line.

[0022] Then, when the amount of imbalance matches any one of the following abnormality determination rule patterns using the above Shewhart control chart, the abnormality detection unit 12 determines that the amount of imbalance exceeds a predetermined range determined in advance, and outputs abnormality detection data.

[0023] Here, the abnormality detection rules are: (1) patterns in which the unbalance amount exceeds the upper or lower control limit line; (2) patterns in which a series of unbalance amounts appear; (3) patterns in which a trend in the unbalance amount appears; (4) patterns in which the unbalance amount fluctuates alternately in succession; (5) patterns in which two out of three consecutively measured unbalance amounts exceed μ±2σ; (6) patterns in which four out of five consecutively measured unbalance amounts exceed μ±σ; (7) patterns in which the unbalance amount is consecutively near the center line; and (8) patterns in which eight consecutively measured unbalance amounts exceed μ±σ.

[0024] The status data storage unit 13 is set in a predetermined area of ​​the memory and stores status data determined based on the maintenance status of the measurement mechanism 11. In this embodiment, the status data is calibration data indicating data related to the calibration of the measurement mechanism 11, or preventive maintenance indicators indicating indicators related to preventive maintenance of the measurement mechanism 11. The status data storage unit 13 is provided in a computing device composed of a so-called computer equipped with a CPU, memory, input / output means, etc., and the status data is created by the user or the computing device and input to the status data storage unit 13.

[0025] Here, the calibration data for the measurement mechanism 11 is the calibration history of the sensor unit 115, etc., within a set period, or the calibration results of the sensor unit 115, etc.

[0026] Furthermore, the preventive maintenance indicators for the measurement mechanism 11 are indicators that show the wear of the components that make up the measurement mechanism 11, such as bearings 111, springs 112, belts 113, and motors 114. Specifically, the preventive maintenance indicators are thresholds for the number of measurements, rotational speed, acceleration time, or number of shots for those components.

[0027] Alternatively, the system may simply indicate that the system is normal if calibration data for a predetermined period is stored, and abnormal if calibration data for a predetermined period is not stored. When the abnormality detection unit 12 diagnoses that the measurement mechanism 11 is normal, it adds to the abnormality detection data that the abnormality occurred in the manufacturing process. That is, the abnormality detection unit 12 outputs abnormality detection data indicating that an abnormality has occurred in the manufacturing process. On the other hand, when the system diagnoses that the measurement mechanism 11 is abnormal, it adds to the abnormality detection data that the abnormality occurred in the measurement mechanism 11. That is, the abnormality detection unit 12 outputs abnormality detection data indicating that an abnormality has occurred in the measurement mechanism 11, not the manufacturing process.

[0028] The display unit 14 displays the amount of unbalance and anomaly detection data. Specifically, as shown in Figure 2, the display unit 14 displays the amount of unbalance on the left or right side of the workpiece W. Furthermore, if the amount of unbalance exceeds a predetermined range, the display unit 14 displays anomaly detection data with the location of the anomaly added.

[0029] In this embodiment, if the amount of unbalance does not exceed a predetermined range, the workpiece W is sent to the unbalance correction device 20 by a transport loader (not shown). Based on the measured amount of unbalance, the unbalance correction device 20 corrects the unbalance on the left and right sides of the workpiece W by drilling the side with the larger unbalance.

[0030] After the unbalance of the workpiece W is corrected, the workpiece W is transported to the unbalance measuring device 10 by a transport loader, and the amount of unbalance of the workpiece W is measured again. In this embodiment, the unbalance measurement and correction of the workpiece W are performed until the amount of unbalance of the workpiece W is below a set value that can guarantee the quality of the workpiece W.

[0031] <2. Method for measuring imbalance> A method for measuring the unbalance of a workpiece W using the unbalance measuring device 10 configured in this way will be explained with reference to Figure 3.

[0032] After going through the prescribed manufacturing process, the workpiece W is attached to the measuring mechanism 11, and the amount of unbalance of the workpiece W is measured.

[0033] When the unbalance amount of the workpiece W is measured, the anomaly detection unit 12 determines whether the unbalance amount exceeds a predetermined range. If the unbalance amount does not exceed the predetermined range, the workpiece W is transported to the unbalance correction device 20. If the unbalance amount exceeds the predetermined range, the anomaly detection unit 12 outputs anomaly detection data.

[0034] Subsequently, the anomaly detection unit 12 acquires state data from the state data storage unit 13 and identifies the location of the anomaly based on that state data. If the anomaly detection unit 12 determines that the state data is normal, it adds to the anomaly detection data that the location of the anomaly is the manufacturing process. If the anomaly detection unit 12 determines that the state data is abnormal, it adds to the anomaly detection data that the location of the anomaly is the measurement mechanism 11.

[0035] Once the location of the anomaly is identified, the display unit 14 displays the amount of imbalance and the anomaly detection data.

[0036] <3. Other Embodiments> However, the present invention is not limited to the embodiments described above.

[0037] In this embodiment, the unbalance amount was a two-dimensional value indicating the magnitude and angle of the unbalance of the workpiece W, but the unbalance amount is not limited to a two-dimensional value. For example, the unbalance amount may be a three-dimensional value indicating the eccentricity distance and eccentricity position of the workpiece W, or it may be a one-dimensional value indicating the eccentricity distance of the workpiece W.

[0038] In this embodiment, the anomaly detection unit 12 identifies the location of the anomaly after determining the amount of imbalance, but the order of calculations is not limited to this. For example, the anomaly detection unit 12 may diagnose whether the measurement mechanism 11 is normal based on the status data, and if the measurement mechanism 11 is diagnosed as normal, it may determine the amount of imbalance.

[0039] In this embodiment, the anomaly detection unit 12 outputs anomaly detection data only for workpieces before unbalance correction is performed. However, the anomaly detection unit 12 may also output anomaly detection data for workpieces after unbalance correction is performed.

[0040] In this embodiment, the unbalance correction system 100 includes an unbalance correction device 20, but it is not necessary to include the unbalance correction device 20.

[0041] In this embodiment, the unbalance correction device 20 corrects the unbalance of the workpiece W by cutting it with a drill, but the correction of the unbalance of the workpiece W is not limited to this. For example, the user may correct the unbalance of the workpiece W by cutting the workpiece W or welding a weight to the workpiece W, based on the amount of unbalance.

[0042] In this embodiment, the unbalance measuring device 10 measures the dynamic unbalance generated by rotating the workpiece W, but it may also measure the static unbalance of the workpiece W. In this case, the unbalance measuring device 10 may consist of only one bearing 111 and one vibration detection sensor 115b, and the workpiece W does not have to be a rotating body.

[0043] In this embodiment, the anomaly detection unit 12 detects anomalies using an anomaly judgment rule based on a Shewhart control chart, but it may also detect anomalies by other methods. For example, the anomaly detection unit 12 may detect anomalies using an anomaly judgment rule based on Hotelling's theory. In this case, an anomaly degree a(x) shown in the following equation 1 is calculated.

[0044]

number

[0045] Note that x is the measured amount of unbalance, μ is the mean value of the unbalance, and σ is the standard deviation of the unbalance.

[0046] A threshold for the anomaly degree a(x) is set, and when the anomaly degree a(x) exceeds the threshold, the anomaly detection unit 12 determines that the amount of imbalance corresponding to that anomaly degree a(x) exceeds a predetermined range and outputs anomaly detection data. Machine learning may be used to calculate the anomaly degree a(x).

[0047] Furthermore, the anomaly detection unit may be provided as an application, allowing it to be retrofitted to existing unbalance measuring devices and correction devices. In this case, the anomaly detection unit, which is composed of a computer, corresponds to an anomaly detection device.

[0048] Furthermore, the anomaly detection unit may be composed of, for example, artificial intelligence (AI), and the AI ​​may detect anomalies in the manufacturing process based on the measured amount of unbalance without determining a predetermined range for the amount of unbalance.

[0049] Furthermore, it goes without saying that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from its spirit.

[0050] <4. Summary> The characteristics of the above-mentioned configuration can be summarized as follows:

[0051] [1] An unbalance measuring device 10 comprises a measuring mechanism 11 for measuring the amount of unbalance of a workpiece W that has gone through a predetermined manufacturing process, and an abnormality detection unit 12 for detecting an abnormality in the predetermined manufacturing process based on the amount of unbalance measured by the measuring mechanism and outputting abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process.

[0052] With this configuration, the output of anomaly detection data can reliably inform the user that an unexpectedly unbalanced amount of workpieces is being manufactured, prompting them to investigate the possibility of some kind of malfunction in the preceding manufacturing process. As a result, the workpiece manufacturing process can be made more efficient, and ultimately, the quality of the workpieces can be guaranteed.

[0053] [2] The unbalance measuring device 10 according to [1], wherein the abnormality detection unit 12 determines whether the amount of unbalance exceeds a predetermined range, and if it determines that the amount of unbalance exceeds the predetermined range, it outputs the abnormality detection data.

[0054] With this configuration, if the amount of imbalance exceeds a predetermined range, an abnormality in the manufacturing process is suspected. Therefore, by outputting abnormality detection data, the user can be reliably informed that workpieces with an unexpectedly large amount of imbalance are being manufactured, and can be prompted to check for any possible malfunctions in the preceding manufacturing process.

[0055] [3] The aforementioned predetermined range is determined based on statistical data showing the statistics of the unbalance amounts of multiple workpieces W of the same type, according to the unbalance measuring device 10 described in [2].

[0056] With this configuration, the anomaly detection unit 12 uses the unbalance amounts of multiple workpieces W of the same type, so it can more accurately determine whether the measured unbalance amount is abnormal by comparing it with the unbalance amounts of other workpieces.

[0057] [4] The anomaly detection unit 12 outputs the anomaly detection data only for workpieces before unbalance correction is performed. This is the unbalance measuring device 10 according to any one of [1] to [3].

[0058] With this configuration, the anomaly detection unit 12 uses only the amount of unbalance of the workpiece W before the unbalance correction is performed, so it can detect an anomaly regardless of the accuracy of the unbalance correction of the workpiece W. Furthermore, if abnormality detection data is output using only the amount of unbalance of the workpiece W before the unbalance correction is performed, it can be determined that an abnormality has occurred in either the preceding manufacturing process or the measurement mechanism 11.

[0059] [5] The unbalance measuring device 10 according to any one of [1] to [4] further comprises a state data storage unit 13 that stores state data which is data indicating the state of the measuring mechanism, the abnormality detection unit 12 acquires the state data from the state data storage unit 13, diagnoses whether the measuring mechanism 11 is normal or not based on the state data, and outputs the abnormality detection data if the measuring mechanism is diagnosed as normal.

[0060] With this configuration, anomaly detection data indicating an abnormality in the manufacturing process is output only when the measurement mechanism 11 is diagnosed as normal, based on the amount of imbalance, thus enabling the output of more accurate anomaly detection data.

[0061] [6] The unbalance measuring device 10 described in [5] outputs abnormality detection data indicating that an abnormality has occurred in the measuring mechanism rather than in the predetermined manufacturing process, when it has diagnosed that the measuring mechanism 11 is abnormal.

[0062] With this configuration, by diagnosing whether the measurement mechanism 11 is functioning correctly based on the status data, it is possible to identify whether an abnormality has occurred in the manufacturing process or the measurement mechanism 11, and thus prompt the user to check the location of the abnormality.

[0063] [7] The state data is determined based on the maintenance status of the measuring mechanism 11, as described in [5] or [6], for the unbalance measuring device 10.

[0064] With this configuration, the maintenance status of the measurement mechanism 11 can be revealed from the status data, allowing for a more accurate diagnosis of whether the measurement mechanism 11 is functioning correctly.

[0065] [8] An unbalance measurement method comprising measuring the amount of unbalance of a workpiece that has undergone a predetermined manufacturing process, detecting an abnormality in the predetermined manufacturing process based on the amount of unbalance measured by the measuring mechanism, and outputting abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process.

[0066] With this configuration, the same effects and advantages as the unbalance measuring device 10 according to the present invention can be obtained.

[0067] [9] An unbalance measurement program that causes a computer to perform the following steps: measure the amount of unbalance of a workpiece that has gone through a predetermined manufacturing process; and, based on the amount of unbalance measured by the measuring mechanism, detect an abnormality in the predetermined manufacturing process and output abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process.

[0068] With this configuration, the same effects and advantages as the unbalance measuring device 10 according to the present invention can be obtained. [Industrial applicability]

[0069] According to the present invention, the output of the anomaly detection data reliably informs the user that an unplanned amount of unbalanced workpieces is being manufactured, prompting them to check for any possible malfunctions in the preceding manufacturing process. As a result, the manufacturing process can be made more efficient, and ultimately, the quality of the workpiece can be guaranteed. [Explanation of Symbols]

[0070] 10. Unbalance measuring device 11...Measurement mechanism 12 ···Anomaly detection unit 13. Status data storage unit 14...Display section 20 ···Unbalance correction device 100...Unbalance Correction System W ···Work

Claims

1. A measuring mechanism for measuring the amount of imbalance in a workpiece after it has gone through a predetermined manufacturing process, A state data storage unit that stores state data which is data indicating the state of the measurement mechanism, The system includes an abnormality detection unit that detects an abnormality in the predetermined manufacturing process based on the amount of imbalance measured by the measurement mechanism and outputs abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process. The aforementioned abnormality detection unit, The system retrieves the status data from the status data storage unit and diagnoses whether the measurement mechanism is functioning correctly based on the status data. An unbalance measuring device that outputs the abnormality detection data when the amount of unbalance measured by the measuring mechanism exceeds a predetermined range and the measuring mechanism is diagnosed as being normal.

2. The unbalance measuring device according to Claim 1, wherein the abnormality detection unit outputs abnormality detection data indicating that an abnormality has occurred in the measurement mechanism, rather than in the predetermined manufacturing process, when the amount of unbalance measured by the measurement mechanism exceeds a predetermined range, but the measurement mechanism is diagnosed as being abnormal.

3. The unbalance measuring device according to Claim 1, wherein the state data is determined based on the maintenance status of the measuring mechanism, or calibration data indicating data relating to the calibration of the measuring mechanism, or information on whether or not calibration data within a predetermined period is stored, or a preventive maintenance index indicating data relating to preventive maintenance of the measuring mechanism.

4. The unbalance measuring device according to claim 1, wherein the predetermined range is determined based on statistical data showing the statistics of unbalance amounts of multiple workpieces of the same type.

5. The unbalance measuring device according to claim 1, wherein the abnormality detection unit outputs the abnormality detection data only for workpieces before unbalance correction is performed.

6. The measuring mechanism is A bearing on which the axial end of the workpiece is placed, A motor for rotating the workpiece, A vibration detection sensor for detecting vibrations of the bearing, A rotation detection sensor for detecting the rotation of the workpiece, The system includes an unbalance amount calculation unit that calculates the amount of unbalance of the workpiece based on the signal from the vibration detection sensor and the signal from the rotation detection sensor. The unbalance measuring device according to claim 1, wherein the unbalance amount calculation unit calculates the magnitude of vibration on the left and right surfaces of the workpiece from the amplitude values ​​of the signals from the vibration detection sensor, and calculates the phase angles of the left and right surfaces from the transfer relationship between the signals from the rotation detection sensor and the vibration detection sensor.

7. A step of measuring the amount of imbalance of a workpiece that has gone through a predetermined manufacturing process using a measuring mechanism, The steps include: acquiring state data, which is data indicating the state of the measurement mechanism, from the state data storage unit; A step of diagnosing whether the measurement mechanism is functioning normally based on the aforementioned state data, An unbalance measurement method comprising the step of detecting an abnormality in a predetermined manufacturing process and outputting abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process, when the amount of unbalance measured by the measuring mechanism exceeds a predetermined range and the measuring mechanism is diagnosed as being normal.

8. A step of measuring the amount of imbalance of a workpiece that has gone through a predetermined manufacturing process using a measuring mechanism, The steps include: acquiring state data, which is data indicating the state of the measurement mechanism, from the state data storage unit; A step of diagnosing whether the measurement mechanism is functioning normally based on the aforementioned state data, An unbalance measurement program that, when the amount of unbalance measured by the measurement mechanism exceeds a predetermined range and the measurement mechanism is diagnosed as being normal, causes a computer to perform the steps of detecting an abnormality in the predetermined manufacturing process and outputting abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process.

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