Imbalance measurement device, imbalance measurement method, and imbalance measurement 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

Unbalance measurement device, unbalance measurement method, and unbalance measurement program

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

[0002] Conventionally, the amount of unbalance is measured for each workpiece that has undergone a predetermined manufacturing process, and the workpiece is corrected based on the amount of unbalance.

[0003] To measure the imbalance, an imbalance measuring device is used, as described in Patent Document 1, which detects vibrations when the workpiece is rotated and calculates the amount of imbalance of the workpiece based on the detected vibrations.

[0004] However, if an abnormality occurs in the manufacturing process preceding measurement, workpieces that have undergone the abnormal process will be manufactured one after another. If the workpieces are corrected based on the amount of imbalance in these workpieces, a large imbalance correction must be made for each workpiece, which could increase the time and frequency of imbalance correction and could even lead to fatal defects in the manufacturing process itself.

[0005] Furthermore, if the time or frequency of unbalance correction increases too much, it may become difficult to guarantee the final quality of the workpiece.

[0006] JP 2011-12611 A

[0007] The present invention is the first to focus on detecting abnormalities in the manufacturing process based on the measured amount of imbalance, and is intended to detect problems in the manufacturing process as described above as early as possible, thereby ensuring the soundness of the process and ultimately the quality of the workpieces.

[0008] That is, the unbalance measurement device according to the present invention is characterized by comprising a measurement mechanism that measures 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 measurement mechanism and outputs abnormality detection data that indicates that an abnormality has occurred in the predetermined manufacturing process.

[0009] With this configuration, the output of the abnormality detection data can reliably notify the user that workpieces with an unexpected imbalance have been manufactured, and prompt the user to check that there may be some kind of problem in the preceding manufacturing process, which in turn can improve the soundness of the manufacturing process and ultimately ensure the quality of the workpieces.

[0010] 1 is a schematic diagram of an unbalance measurement device according to an embodiment of the present invention. 2 is a schematic diagram of a display unit in a normal state, and 3 is a schematic diagram of a display unit in an abnormal state according to an embodiment of the present invention. 3 is a flowchart of an unbalance measurement method according to an embodiment of the present invention.

[0011] An embodiment of an unbalance measuring device according to the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, some parts may be omitted or exaggerated as needed for clarity. Identical components will be assigned the same reference numerals, and their description will be omitted as needed.

[0012] <1. Device Configuration> The unbalance measurement device 10 in this embodiment measures the unbalance of a workpiece W that has undergone a predetermined manufacturing process, such as cutting, plating, or machining. After being measured by the unbalance measurement 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 measurement device 10 and the unbalance correction device 20 constitute an 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 includes a measuring mechanism 11 that measures the amount of unbalance of the workpiece W, an abnormality detection unit 12 that detects abnormalities based on the amount of unbalance of the workpiece W, a status data storage unit 13 that stores status data that indicates the status of the measuring mechanism 11, and a display unit 14 that displays the amount of unbalance and abnormalities of the workpiece W. Each unit of the unbalance measuring device 10 will be described below.

[0014] The measuring mechanism 11 includes a bearing 111 on which both axial ends of the workpiece W are placed, a spring 112 that supports the bearing 111 so that it can be displaced freely, a belt 113 that is wound around the circumferential direction of the workpiece W, a motor 114 that drives and rotates the belt 113, a sensor unit 115 that detects the vibration of the bearing 111 and the rotation of the workpiece W, and an imbalance amount calculation unit 116 that calculates the imbalance amount 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, and 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 provided in proximity to a mark M affixed to the outer peripheral surface of the workpiece W. When the workpiece W rotates, the rotation detection sensor 115a detects the mark M and outputs a signal whose phase reference is the point in time when the mark M is detected.

[0017] The vibration detection sensors 115b are of a moving coil type provided corresponding to each bearing 111. Specifically, when each bearing 111 vibrates in accordance with the rotation of the workpiece W, the vibration detection sensors 115b detect the displacement of each bearing 111 and output a sinusoidal signal corresponding to the displacement.

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

[0019] In this embodiment, the amount of unbalance is a multidimensional value including the magnitude of vibration on the left and right surfaces of the workpiece W, and a phase angle indicating the angular difference between the maximum value of vibration on the left and right surfaces of the workpiece W and a phase reference. The unbalance amount calculation unit 116 calculates the magnitude of vibration on the left and right surfaces 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 on each of the left and right surfaces from the phase relationship between the signal of the rotation detection sensor 115a and the signals of each vibration detection sensor 115b.

[0020] The anomaly detection unit 12 detects an anomaly in a predetermined manufacturing process based on the amount of imbalance. Specifically, the anomaly detection unit 12 determines whether the amount of imbalance exceeds a predetermined range, and if it determines that the amount of imbalance exceeds the predetermined range, outputs anomaly detection data indicating that an anomaly has occurred in the manufacturing process. For example, the anomaly detection unit 12 outputs anomaly detection data only for workpieces W before imbalance correction is performed. Note that the anomaly detection unit 12 is physically provided in a computing device constituted by a so-called computer equipped with a CPU, memory, input / output means, etc.

[0021] The predetermined range of the unbalance amount described above is determined in advance based on statistical data showing statistics of the unbalance amounts of multiple workpieces of the same type, and the values ​​are stored in a predetermined area of ​​the memory. Specifically, the statistical data includes the measured values ​​of the unbalance amounts of multiple workpieces W of the same type, the average value μ of the unbalance amounts of those workpieces W, and the standard deviation σ of the unbalance amounts of those workpieces W, which are also stored in the memory. In this embodiment, a Shewhart control chart created from the above statistical data is stored in the same memory. The Shewhart control chart uses the average value μ as the center line, and also uses the average value μ and the standard deviation σ to set μ + 3σ as the upper control limit line and μ - 3σ as the lower control limit line.

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

[0023] Here, the abnormality determination rules are: (1) a pattern in which the imbalance amount exceeds the upper control limit line or the lower control limit line; (2) a pattern in which a series of imbalance amounts appears; (3) a pattern in which a trend in the imbalance amount appears; (4) a pattern in which the imbalance amount fluctuates continuously and alternately; (5) a pattern in which two of three imbalance amounts measured in succession exceed μ±2σ; (6) a pattern in which four of five imbalance amounts measured in succession exceed μ±σ; (7) a pattern in which imbalance amounts are consecutively located near the center line; and (8) a pattern in which eight imbalance amounts measured in succession 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 a preventive maintenance index indicating an index related to the preventive maintenance of the measurement mechanism 11. The status data storage unit 13 is provided in a calculation device constituted by a so-called computer equipped with a CPU, memory, input / output means, etc., and the status data is created by a user or the calculation device and input to the status data storage unit 13.

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

[0026] The preventive maintenance index of the measurement mechanism 11 is an index that indicates wear of components that constitute the measurement mechanism 11, such as the bearing 111, the spring 112, the belt 113, and the motor 114. Specifically, the preventive maintenance index is the threshold value of the number of measurements, the number of rotations, the acceleration time, or the number of shots of these components.

[0027] Alternatively, it may be determined that the system is normal if calibration data within a predetermined period has been stored, and that this is the case if calibration data within a predetermined period has not been stored. When the abnormality detection unit 12 diagnoses that the measurement mechanism 11 is normal, it adds to the content of the abnormality detection data that the abnormality has 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 it diagnoses that the measurement mechanism 11 is abnormal, it adds to the content of the abnormality detection data that the abnormality has 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 in the manufacturing process.

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

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

[0030] After correcting the unbalance of the workpiece W, the workpiece W is transported by the transport loader to the unbalance measuring device 10, where the amount of unbalance of the workpiece W is measured again. In this embodiment, the unbalance measurement and unbalance correction of the workpiece W are continued until the amount of unbalance of the workpiece W becomes equal to or less than a set value that can ensure the quality of the workpiece W.

[0031] 2. Unbalance Measuring Method A method for measuring the unbalance of the workpiece W using the unbalance measuring device 10 configured as above will be described with reference to FIG.

[0032] The workpiece W that has undergone a predetermined manufacturing process is attached to the measuring mechanism 11, and the amount of unbalance of the workpiece W is measured.

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

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

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

[0036] 3. Other Embodiments The present invention is not limited to the above-described embodiment.

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

[0038] In this embodiment, the abnormality detection unit 12 determines the amount of imbalance and then identifies the location of the abnormality, but the order of calculations is not limited to this. For example, the abnormality 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, determine the amount of imbalance.

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

[0040] In this embodiment, the unbalance correction system 100 includes the unbalance correction device 20, but the unbalance correction device 20 may not be included.

[0041] In the present embodiment, the unbalance correction device 20 performs cutting using a drill to correct the unbalance of the workpiece W, but the method for correcting 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] The unbalance measuring device 10 in this embodiment measures dynamic unbalance caused by rotating the workpiece W, but it may also measure static unbalance of the workpiece W. In this case, the unbalance measuring device 10 may have 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 determination rule that uses a Shewhart control chart, but it may also detect anomalies using other methods. For example, the anomaly detection unit 12 may detect anomalies using an anomaly determination rule that uses Hotelling's theory. In this case, the anomaly degree a(x) shown in the following equation 1 is calculated.

[0044]

[0045] Here, x is the measured amount of unbalance, μ is the average value of the amount of unbalance, and σ is the standard deviation of the amount of unbalance.

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

[0047] Furthermore, the anomaly detection unit may be provided as an application so that the function can be added later to existing unbalance measurement devices or correction devices. In this case, the anomaly detection unit configured by a computer corresponds to the anomaly detection device.

[0048] Furthermore, the abnormality detection unit may be configured, for example, with artificial intelligence (AI), and may detect abnormalities in the manufacturing process based on the measured amount of imbalance without the AI ​​determining a predetermined range for the amount of imbalance.

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

[0050] <4. Summary> The features of the above-described configuration can be summarized as follows.

[0051] [1] An unbalance measurement device 10 comprising: a measurement mechanism 11 that measures the amount of unbalance of a workpiece W that has undergone a predetermined manufacturing process; and an abnormality detection unit 12 that detects an abnormality in the predetermined manufacturing process based on the amount of unbalance measured by the measurement mechanism and outputs abnormality detection data that indicates that an abnormality has occurred in the predetermined manufacturing process.

[0052] With this configuration, the output of the abnormality detection data can reliably notify the user that an unexpected amount of imbalance has been produced, and prompt the user to check that there may be some kind of problem in the preceding manufacturing process. As a result, the workpiece manufacturing process can be improved, and the quality of the workpieces can be guaranteed.

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

[0054] With this configuration, if the amount of imbalance exceeds a specified range, an abnormality in the manufacturing process is suspected, and the output of abnormality detection data reliably notifies the user that a workpiece with an unexpected amount of imbalance has been manufactured, and prompts the user to check that there may be some kind of problem in the previous manufacturing process.

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

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

[0057] [4] The unbalance measuring device 10 according to any one of [1] to [3], wherein the abnormality detection unit 12 outputs the abnormality detection data only for a workpiece before unbalance correction is performed.

[0058] With this configuration, the abnormality detection unit 12 uses only the amount of unbalance of the workpiece W before unbalance correction is performed, and therefore can detect abnormalities regardless of the accuracy of correcting the unbalance of the workpiece W. Furthermore, when abnormality detection data is output using only the amount of unbalance of the workpiece W before 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 comprising a status data storage unit 13 that stores status data that indicates the status of the measuring mechanism, and the abnormality detection unit 12 acquires the status data from the status data storage unit 13, diagnoses whether the measuring mechanism 11 is normal or not based on the status data, and outputs the abnormality detection data when the measuring mechanism is diagnosed as normal.

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

[0061] [6] The unbalance measuring device 10 according to [5], which, when it is diagnosed that the measuring mechanism 11 is abnormal, outputs abnormality detection data indicating that an abnormality has occurred in the measuring mechanism, not in the specified manufacturing process.

[0062] With this configuration, by diagnosing whether the measurement mechanism 11 is normal or not based on the status data, it is possible to identify whether the abnormality has occurred in the manufacturing process or in the measurement mechanism 11, and therefore it is possible to prompt the user to check where the abnormality has occurred.

[0063] [7] The unbalance measuring device 10 according to [5] or [6], wherein the status data is determined based on a maintenance status of the measuring mechanism 11.

[0064] With this configuration, the maintenance status of the measuring mechanism 11 becomes clear from the status data, so it is possible to more accurately diagnose whether the status of the measuring mechanism 11 is normal.

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

[0066] With this configuration, it is possible to obtain the same effects as those of the unbalance measuring device 10 according to the present invention.

[0067] [9] An unbalance measurement program that causes a computer to execute the steps of: measuring the amount of unbalance of a workpiece that has undergone a predetermined manufacturing process; and detecting an abnormality in the predetermined manufacturing process based on the amount of unbalance measured by the measurement mechanism, and outputting abnormality detection data that indicates that an abnormality has occurred in the predetermined manufacturing process.

[0068] With this configuration, it is possible to obtain the same effects as those of the unbalance measuring device 10 according to the present invention.

[0069] According to the present invention, the output of the abnormality detection data can reliably notify the user that an unexpected amount of unbalance has been produced, and prompt the user to check that there may be some problem in the preceding manufacturing process, which in turn can improve the soundness of the manufacturing process and ultimately ensure the quality of the workpieces.

[0070] REFERENCE SIGNS LIST 10 Unbalance measuring device 11 Measurement mechanism 12 Abnormality detection unit 13 Status data storage unit 14 Display unit 20 Unbalance correction device 100 Unbalance correction system W Workpiece

Claims

1. A measuring mechanism for measuring the amount of imbalance of a workpiece that has undergone a predetermined manufacturing process, A state data storage unit that stores state data, which is data indicating the state of the measuring mechanism, An abnormality detection unit that detects an abnormality in the predetermined manufacturing process based on the amount of imbalance measured by the measuring mechanism and outputs abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process, The abnormality detection unit, acquires the state data from the state data storage unit, diagnoses whether the measuring mechanism is normal based on the state data, An imbalance measuring device that outputs the abnormality detection data when the amount of imbalance measured by the measuring mechanism exceeds a predetermined range and the measuring mechanism is diagnosed as normal.

2. The abnormality detection unit outputs abnormality detection data indicating that an abnormality has occurred not in the predetermined manufacturing process but in the measuring mechanism when the amount of imbalance measured by the measuring mechanism exceeds a predetermined range but the measuring mechanism is diagnosed as abnormal. The imbalance measuring device according to Claim 1.

3. The state data is determined based on the maintenance status of the measuring mechanism, or calibration data indicating data related to the calibration of the measuring mechanism, or information indicating whether calibration data within a predetermined period is stored, or a preventive maintenance index indicating data related to the preventive maintenance of the measuring mechanism. The imbalance measuring device according to Claim 1.

4. The predetermined range is determined based on statistical data indicating the statistics of the amounts of imbalance of a plurality of workpieces of the same type. The imbalance measuring device according to Claim 1.

5. The abnormality detection unit outputs the abnormality detection data only for the workpiece before the imbalance correction is performed. The imbalance measuring device according to Claim 1.

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

7. A step of measuring the imbalance amount of a workpiece that has undergone a predetermined manufacturing process using a measurement mechanism; A step of acquiring state data, which is data indicating the state of the measurement mechanism, from a state data storage unit; A step of diagnosing whether the measurement mechanism is normal based on the state data; When the imbalance amount measured by the measurement mechanism exceeds a predetermined range and the measurement mechanism is diagnosed as normal, detecting an abnormality in the predetermined manufacturing process and outputting abnormality detection data indicating that an abnormality has occurred in the predetermined manufacturing process. An imbalance measurement method including the steps.

8. A step of measuring the imbalance amount of a workpiece that has undergone a predetermined manufacturing process using a measurement mechanism; A step of acquiring state data, which is data indicating the state of the measurement mechanism, from a state data storage unit; A step of diagnosing whether the measurement mechanism is normal based on the state data; When the imbalance amount measured by the measurement mechanism exceeds a predetermined range and the measurement mechanism is diagnosed as normal, causing a computer to execute a step 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. An imbalance measurement program.