Motor-equipped roller and method for detecting abnormality in same

Abstract

A motor-equipped roller 1 comprises: a motor 3; a vibration sensor 16 for outputting vibration data generated by rotation of the motor 3; an analysis unit 17 for performing frequency analysis of the vibration data to extract a vibration value for a prescribed frequency; and an abnormality detection unit 18 for comparing at least an initial vibration value for the prescribed frequency, said initial vibration value being extracted by analyzing vibration data for the time of an initial operation, and a current vibration value for the prescribed frequency, said current vibration value being extracted by analyzing current vibration data, to detect an abnormality in a portion corresponding to the prescribed frequency.

Description

Motorized roller and its abnormality detection method

[0001] The present disclosure relates to a motorized roller and a method for detecting an abnormality therein.

[0002] If a motorized roller built into a conveyor fails, the conveyor will stop and cause downtime. When downtime occurs, emergency maintenance is required to replace the motorized roller, and an investigation into the cause is also required. Because these operations and investigations are costly and time-consuming, it is important to detect abnormalities in motorized rollers early.

[0003] Conventionally, one way to detect abnormalities in motorized rollers is to output an error signal from the motor driver and check the motor's error status. However, this method only reveals the motor's error log (motor overload, voltage drop, etc.), and it is not clear which part of the motorized roller has the abnormality.

[0004] Furthermore, Patent Document 1 discloses a means for detecting an abnormality by comparing rotation information and / or power information when a roller conveyor is functioning normally with current rotation information and / or power information. It also discloses that by comparing the amount of change in current, wear or looseness in the drive system can be determined, and by comparing the amount of change in rotation speed, wear in the belt or gears can be determined. However, even with this means, it is unclear which part of the motorized roller has an abnormality.

[0005] JP 2012-71988 A

[0006] An object of the present disclosure is to provide a motorized roller that allows a location where an abnormality has occurred to be identified, and a method for detecting an abnormality therein.

[0007] The motorized roller of the present disclosure comprises a motor, a vibration sensor that outputs vibration data generated by rotation of the motor, an analysis unit that performs frequency analysis on the vibration data to extract vibration values ​​of a predetermined frequency, and an abnormality detection unit that detects abnormalities in a part corresponding to the predetermined frequency by comparing at least an initial vibration value of the predetermined frequency extracted by analyzing vibration data during initial operation with a current vibration value of the predetermined frequency extracted by analyzing current vibration data.

[0008] With this configuration, the abnormality detection unit can detect an abnormality in a part corresponding to a predetermined frequency by comparing the initial vibration value with the current vibration value of the predetermined frequency, thereby making it possible to identify the part of the motorized roller where an abnormality has occurred.

[0009] 1 is a plan view showing a conveyance device equipped with a motorized roller according to the present embodiment; 2 is a schematic cross-sectional view of the motorized roller according to the present embodiment; 3 is a graph illustrating the relationship between vibration values ​​and frequency after analysis in the motorized roller according to the present embodiment; 4 is a flowchart showing an abnormality detection method for the motorized roller according to the present embodiment; and 5 is a graph showing the relationship between vibration values ​​and frequency when the motorized roller according to the example is abnormally fixed.

[0010] [Conveying Device] An embodiment of a conveying device 100 equipped with a motorized roller 1 according to this embodiment will be described with reference to FIG. 1. Note that in each figure (as well as FIGS. 2 to 4), the dimensional ratios shown in the drawing do not necessarily match the actual dimensional ratios. Furthermore, the dimensional ratios between the drawings do not necessarily match. FIG. 1 is a plan view of the conveying device 100.

[0011] As shown in Fig. 1, conveying device 100 extends along the conveying direction and conveys article 200 from upstream to downstream. Specifically, article 200 is conveyed in the order of zone A, zone B, and zone C. In Fig. 1, conveying device 100 extends linearly, but it may also extend curvedly. Furthermore, conveying device 100 may be composed of four or more zones, or may be composed of one or two zones.

[0012] The conveying device 100 comprises a plurality of motor-integrated rollers 1 (also called drive rollers 1), a plurality of driven rollers 101, a pair of frames 102, 102 supporting the plurality of motor-integrated rollers 1 and the plurality of driven rollers 101, a conveyed object detection sensor 103 that detects the presence or absence of a conveyed object 200, and a conveying control unit 104.

[0013] The multiple motorized rollers 1 are arranged at predetermined intervals in the conveying direction. In this embodiment, one motorized roller 1 is provided for each of zones A to C, but this is not limited to this. For example, two motorized rollers 1 may be provided for each of zones A to C. Details of the motorized rollers 1 will be described later.

[0014] The driven rollers 101 are provided at predetermined intervals in the conveying direction. A plurality of driven rollers 101 are provided in each of zones A to C, and are connected to the motorized roller 1 by a belt 105. As a result, when the motorized roller 1 rotates, the driven roller 101 rotates in conjunction with it via the belt 105. The driven roller 101 may be connected to the motorized roller 1 by a chain, or may not be connected to the motorized roller 1.

[0015] 1 shows an example in which four driven rollers 101 are provided upstream of the motorized roller 1 and five driven rollers 101 are provided downstream of the motorized roller 1. That is, while FIG. 1 shows an example in which one motorized roller 1 and nine driven rollers 101 are provided in each of zones A to C, the present invention is not limited to this.

[0016] The transported object detection sensors 103 are provided, for example, downstream of each of zones A to C. The transported object detection sensors 103 are, for example, photoelectric sensors or laser sensors. The transport control unit 104 is composed of a computer, for example, a general-purpose personal computer, a PLC (Programmable Logic Controller), a motion controller, or other such computer. The transport control unit 104 sends a signal to switch the motorized roller 1 on and off depending on the detection status of the transported object 200. As a result, the motorized roller 1 repeatedly rotates and stops in response to the signal sent from the transport control unit 104.

[0017] The conveying device 100 may be configured without the conveyed object detection sensor 103. When a load is applied to the motor 3 of the motorized roller 1, the Hall IC signal of the motor 3 switches to H or L, so it is possible to detect this change and automatically control the rotation or stop of the motor 3 (motorized roller 1).

[0018] [Motorized Roller] Next, the motorized roller 1 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view of the motorized roller 1.

[0019] As shown in Figure 2, the motorized roller 1 includes, for example, a roller tube 2, a motor 3 provided inside the roller tube 2, a reducer 4 that reduces the rotational speed of the motor 3, a power transmission unit 5 that transmits the rotation of the output shaft 41 of the reducer 4 to the roller tube 2, a first shaft 6 that protrudes from one end of the roller tube 2, and a second shaft 7 that protrudes from the other end of the roller tube 2.

[0020] The first shaft 6 is, for example, a cylindrical member extending along the longitudinal direction of the roller tube 2. The second shaft 7 is, for example, a columnar member extending along the longitudinal direction of the roller tube 2. The first shaft 6 and the second shaft 7 are formed of a metal (including alloys) such as stainless steel or general steel (S45C or SS400). The first shaft 6 is fixed to one frame 102, and the second shaft 7 is fixed to the other frame 102.

[0021] The roller tube 2 is a cylindrical member made of a metal (including alloys), such as stainless steel or general steel (STKM or S45C). A first side member 8 is fitted to one end of the roller tube 2, and a second side member 9 is fitted to the other end of the roller tube 2. A bearing 10 is fitted to the first side member 8, and the first shaft 6 is inserted through the bearing 10. A bearing 11 is fitted to the second side member 9, and the second shaft 7 is inserted through the bearing 11.

[0022] The motor 3 is, for example, a brushless motor having an output shaft 31, a rotor 32 (also called rotor 32) provided with a plurality of permanent magnets, bearings 33a and 33b supporting the output shaft 31 and rotor 32, and a stator 34 (also called stator 34) provided with a plurality of coils (windings).

[0023] The reducer 4 includes, for example, an output shaft 41 and a planetary gear mechanism 42. The planetary gear mechanism 42 is provided with one or more stages inside the motorized roller 1. Fig. 2 shows an example in which the planetary gear mechanism 42 is provided with two stages. The number of stages of the planetary gear mechanism 42 is set appropriately depending on the reduction ratio.

[0024] The planetary gear mechanism 42 is composed of a sun gear fixed to the output shaft 31 of the motor 3 or a planet carrier of another planetary gear mechanism, multiple planet gears arranged around the sun gear, a planet carrier supporting the multiple planet gears, and an internal gear arranged to surround the sun gear and the multiple planet gears. The planet gears mesh with each of the sun gear and the internal gear. The output shaft 41 of the reducer 4 is fixed to the planet carrier of the planetary gear mechanism 42 located at the lowest stage.

[0025] The power transmission unit 5 is a cylindrical member fixed to the output shaft 41 of the reducer 4 , and is fixed to the inner peripheral surface of the roller tube 2 .

[0026] The motorized roller 1 includes a circuit board 12 provided inside the roller tube 2, and a cable 13 connected to the circuit board 12. The cable 13 runs from the outside of the motorized roller 1 through the first shaft 6 and is connected to the circuit board 12. The cable 13 is, for example, a power line or a signal line.

[0027] The motorized roller 1 includes a motor control unit 14 that controls the motor 3, and a motor drive unit 15 that drives the motor 3. The motor control unit 14 and the motor drive unit 15 are provided inside the motorized roller 1. Specifically, the motor control unit 14 and the motor drive unit 15 are provided on a circuit board 12.

[0028] The motor control unit 14 controls the motor drive unit 15 to control the motor 3. For example, when the motor control unit 14 outputs a control signal to the motor drive unit 15, current flows from the motor drive unit 15 to the motor 3, causing the motor 3 to rotate. The motor control unit 14 may be provided inside the motorized roller 1 or outside the motorized roller 1. When the motor control unit 14 is provided outside the motorized roller 1, the conveyance control unit 104 shown in FIG. 1 may be the motor control unit 14.

[0029] The motorized roller 1 includes a vibration sensor 16 for outputting vibration data generated by the rotation of the motor 3, and an analyzer 17 for performing frequency analysis on the vibration data output by the vibration sensor 16 to extract vibration values ​​of a predetermined frequency. The vibration sensor 16 is, for example, an acceleration sensor, a displacement sensor, or a speed sensor. In this embodiment, the vibration sensor 16 is an acceleration sensor, but is not limited to this. The vibration sensor 16 and the analyzer 17 are provided inside the motorized roller 1. Specifically, the vibration sensor 16 and the analyzer 17 are provided on the circuit board 12.

[0030] The analysis unit 17 performs frequency analysis using, for example, a Fourier transform (FT), which may be a fast Fourier transform (FFT) or a discrete Fourier transform (DFT).

[0031] The predetermined frequency is a frequency at a predetermined rotation speed of the motor 3. Examples of the predetermined frequency include a motor rotation frequency f1 at the rotor 32, a motor rotation frequency f2 at the stator 34, a frequency f3a of the inner ring of the bearing 33a on the output shaft 31 side, a frequency f4a of the outer ring of the bearing 33a on the output shaft 31 side, a frequency f5a of the rolling elements of the bearing 33a on the output shaft 31 side, a frequency f3b of the inner ring of the bearing 33b on the circuit board 12 side, a frequency f4b of the outer ring of the bearing 33b on the circuit board 12 side, a frequency f5b of the rolling elements of the bearing 33b on the circuit board 12 side, and a frequency f6a of the sun gear of the planetary gear mechanism 42a (first stage). These are meshing frequency (SP) f6 with the planet gear, meshing frequency (PI) f7 between the planet gear of the planetary gear mechanism 42a (first stage) and the internal gear, meshing frequency (SP) f8 between the sun gear of the planetary gear mechanism 42b (second stage) and the planet gear, meshing frequency (PI) f9 between the planet gear of the planetary gear mechanism 42b (second stage) and the internal gear, meshing frequency (SP) f10 between the sun gear of the planetary gear mechanism (third stage) and the planet gear, and meshing frequency (PI) f11 between the planet gear of the planetary gear mechanism (third stage) and the internal gear. Each of the frequencies f1 to f11 can be calculated using known formulas.

[0032] Table 1 below illustrates the relationship between the reduction ratio and each frequency f1 to f11. Reduction ratios 1 to 13 shown in Table 1 decrease from top to bottom. That is, reduction ratio 1 is the largest, and reduction ratio 13 is the smallest. The reducers 4 for reduction ratios 1 to 5 are configured with a three-stage planetary gear mechanism 42, the reducers 4 for reduction ratios 6 to 9 are configured with a two-stage planetary gear mechanism 42, and the reducers 4 for reduction ratios 10 to 13 are configured with a single-stage planetary gear mechanism 42. Frequencies f1 to f5 are constant regardless of the reduction ratio, and meshing frequencies f6 to f11 change depending on the reduction ratio.

[0033]

[0034] The vibration value is, for example, the average value of the vibration values ​​in the X, Y, and Z directions. The X direction is the axial direction of the motorized roller 1, the Y direction is the direction perpendicular to the X direction in a horizontal plane, and the Z direction is the direction perpendicular to the X and Y directions (vertical direction). The vibration value may be the vibration value in any one of the X, Y, and Z directions, or may be the average value of the vibration values ​​in any two of the X, Y, and Z directions. The unit of the vibration value is m / s ２ or dB.

[0035] The motorized roller 1 is equipped with an abnormality detection unit 18 that detects an abnormality in a part corresponding to the predetermined frequency by comparing an initial vibration value of the predetermined frequency extracted by analyzing vibration data from the motorized roller 1 during initial operation by the analysis unit 17 with a current vibration value of the predetermined frequency extracted by analyzing current vibration data from the motorized roller 1 by the analysis unit 17. With this configuration, the abnormality detection unit 18 can detect an abnormality in a part corresponding to the predetermined frequency by comparing the initial vibration value of the predetermined frequency with the current vibration value. This makes it possible to identify the part of the motorized roller 1 where an abnormality has occurred. As a result, the accuracy of abnormality detection in the motorized roller 1 can be improved.

[0036] The initial operation of the motorized roller 1 refers to, for example, the unloaded or loaded operation of the motorized roller 1 during shipping inspection. Unloaded operation refers to the operation of the motorized roller 1 alone, i.e., the operation of the motorized roller 1 when it is not connected to the driven roller 101 by the belt 105 shown in FIG. 1 . Loaded operation refers to the operation of rotating the driven roller 101 together with the motorized roller 1, i.e., the operation of the motorized roller 1 when it is connected to the belt 105. The initial vibration value tends to be larger during loaded operation than during unloaded operation. Note that, for example, the initial operation of the conveying device 100 may also be considered the initial operation of the motorized roller 1.

[0037] The current vibration data of the motorized roller 1 is vibration data of the motorized roller 1 when the conveyance device 100 is actually operating, and does not include vibration data of the motorized roller 1 when it is initially operating.

[0038] The part corresponding to the predetermined frequency is, for example, the part (such as the rotor 32 of the motor 3) shown in Table 1. For example, the abnormality detection unit 18 can detect whether there is an abnormality in the rotor 32 by comparing the initial vibration value at the motor rotation frequency of the rotor 32 with the current value, and can detect whether there is an abnormality in the stator 34 (or the case of the motor 3) by comparing the initial vibration value at the motor rotation frequency of the stator 34 with the current vibration value.

[0039] The abnormality detection unit 18 compares the initial vibration value with the current vibration value, and detects an abnormality in a part corresponding to a predetermined frequency if the difference between them is equal to or greater than a predetermined value. The predetermined (vibration) value is a threshold value that is appropriately set depending on the magnitude of the initial vibration value, etc. The predetermined (vibration) value is, for example, 10% or 20% of the initial vibration value.

[0040] FIG. 3 is a graph illustrating the relationship between vibration values ​​and frequency after analysis for the motorized roller 1. In FIG. 3, the solid line indicates the initial vibration value, and the dashed line indicates the current vibration value. As shown in FIG. 3, when the predetermined value is set to 10% of the initial vibration value, the current vibration values ​​at frequencies fa, fb, and fc are greater than the initial vibration value by a predetermined value or more. In this case, the abnormality detection unit 18 detects an abnormality in the portion corresponding to each frequency fa, fb, or fc. Note that FIG. 3 shows an example in which the vibration values ​​at three frequencies have changed by a predetermined value or more, but this is not limited to this. For example, the vibration values ​​at one, two, or four or more frequencies may have changed by a predetermined value or more. Furthermore, the current vibration value may be smaller than the initial vibration value by a predetermined value or more.

[0041] 2, the motorized roller 1 preferably includes a storage unit 19 that stores at least the initial vibration values ​​at a predetermined frequency. The storage unit 19 stores, for example, the type of motor 3, the reduction ratio of the reducer 4, the contents of Table 1, and the initial vibration values ​​at each frequency in Table 1.

[0042] The storage unit 19 is preferably provided inside the motorized roller 1. This allows a one-to-one correspondence between the motor drive unit 15 and the motorized roller 1, unlike when the motor drive unit 15 is provided outside the motorized roller 1. However, the storage unit 19 is not limited to the above, and may be provided outside the motorized roller 1.

[0043] The current vibration value is preferably a vibration value of a predetermined frequency extracted by analyzing vibration data during the origin return operation of the motor 3. This configuration prevents vibrations occurring when the transported object 200 (see FIG. 1) is transported from being included in the current vibration value. This improves the accuracy of abnormality detection by the abnormality detection unit 18. The origin return operation of the motor 3 is performed when the transported object 200 is not loaded on the transport device 100 (see FIG. 1), and is an operation that is performed once a day, for example, at the start of work. Note that the current vibration value is not limited to the above, and may be, for example, a vibration value of a predetermined frequency extracted by analyzing vibration data during the transport of the transported object 200.

[0044] When the predetermined frequency is an integer multiple (including 1) of the motor rotation frequency of the stator 34 of the motor 3, the anomaly detection unit 18 preferably detects a first anomaly when the current vibration value is smaller than the initial vibration value by a predetermined value or more. This configuration makes it possible to detect a first anomaly in the motorized roller 1. This makes it possible to detect, for example, an anomaly in the fixation of the motorized roller 1 to the frame 102 (such as insufficient fixation). As a result, for example, by detecting an anomaly in the fixation of the motorized roller 1 early, it is possible to prevent failure of the motorized roller 1 and prevent downtime in the conveyance device 100 in which the motorized roller 1 is installed.

[0045] Because the case (holding the stator 34) of the motor 3 and the first shaft 6 are fixed, it is thought that vibrations in the stator 34 portion are transmitted to the first shaft 6. If there is an abnormality in the fixing of the motor-incorporated roller 1, it is thought that vibrations in the stator 34 portion are not transmitted to the first shaft 6 and are instead released, causing the current vibration value to become smaller than the initial vibration value.

[0046] The frequency that is an integer multiple of the motor rotation frequency in the stator 34 is set appropriately depending on the type of motor and the fixing method of the motor-incorporated roller 1. When the first abnormality is detected, it is preferable to replace or repair the motor-incorporated roller 1 during regular maintenance.

[0047] When the predetermined frequency is the meshing frequency of the gears (of the planetary gear mechanism 42) in the reducer 4, the anomaly detection unit 18 preferably detects a second anomaly when the current vibration value is greater than the initial vibration value by a predetermined value or more. This configuration makes it possible to detect a second anomaly in the motorized roller 1. This allows, for example, detection of gear wear in the reducer 4 in the motorized roller 1, which is a second anomaly. As a result, for example, early detection of gear wear in the reducer 4 allows for early replacement of the motorized roller 1, thereby shortening downtime caused by failure of the motorized roller 1. Increased gear wear in the reducer 4 increases backlash, which in turn increases rotational irregularities and vibration, potentially causing the current vibration value to exceed the initial vibration value. When a second anomaly is detected, it is preferable to replace or repair the motorized roller 1 during regular maintenance.

[0048] In this embodiment, it is possible to detect meshing portions where gear wear has occurred by comparing the initial vibration value with the current vibration value at each meshing frequency f6 to f11 in Table 1. For example, when the predetermined frequency is meshing frequency f6, it is possible to detect gear wear at the meshing portions between the sun gear and planet gears in the first-stage planetary gear mechanism 42.

[0049] The motorized roller 1 preferably includes a current sensor 20 that detects the current flowing through the motor 3. The abnormality detection unit 18 preferably detects a third abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current sensor 20 detects that an overcurrent is flowing through the motor 3. This configuration makes it possible to detect the third abnormality of the motorized roller 1. This allows, for example, detection of a third abnormality, such as a gear jamming in the reducer 4 (planetary gear mechanism 42). As a result, for example, early detection of a gear jamming in the reducer 4 facilitates the determination of whether to replace the motorized roller 1. When the gear jamming in the reducer 4 occurs, rotation of the motor 3 is suppressed, and the current vibration value is thought to be smaller than the initial vibration value. In this case, an overcurrent is thought to flow through the motor 3. When the third abnormality is detected, it is considered urgent, so it is preferable to perform emergency maintenance and replace or repair the motorized roller 1.

[0050] The abnormality detection unit 18 may detect the third abnormality by comparing the current vibration value of any one of the frequencies f1 to f11 shown in Table 1 with the initial vibration value, or may detect the third abnormality by comparing the current vibration value of any two or more of the frequencies f1 to f11 shown in Table 1 with the initial vibration value. For example, if the gears are jammed and the motor 3 is constrained, the current vibration value will be smaller than the initial vibration value at all frequencies. The same applies to the fourth abnormality described below.

[0051] The abnormality detection unit 18 preferably detects a fourth abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current value of the motor 3 falls below a predetermined current value. This configuration makes it possible to detect the fourth abnormality of the motorized roller 1. Therefore, for example, by detecting the fourth abnormality, i.e., a spinning abnormality of the motorized roller 1, the motorized roller 1 can be replaced early, thereby shortening downtime caused by a motorized roller 1 failure. A spinning abnormality is, for example, an abnormality in which the motorized roller 1 does not rotate and the internal motor 3 or gears of the reducer 4 spin freely. When a spinning abnormality of the motorized roller 1 occurs, the vibration of the motorized roller 1 is reduced, and the current vibration value is thought to be smaller than the initial vibration value. Furthermore, in this case, the load on the motor 3 is thought to be reduced, and the current value flowing through the motor 3 is thought to be reduced. When the fourth abnormality is detected, the emergency situation is high, so it is preferable to perform emergency maintenance and replace or repair the motorized roller 1.

[0052] The predetermined current value is a threshold value that is set appropriately depending on the type of motor 3. The predetermined current value is, for example, 40% of the rated current value. The idling abnormality occurs, for example, when the fixation (press-fit) between the output shaft 31 (or planetary carrier) of the motor 3 and the sun gear is released or when the gear of the reducer 4 is worn.

[0053] When the abnormality detection unit 18 detects the first or second abnormality, the motor control unit 14 preferably controls the motor 3 to extend the stop time (for example, 0.5 seconds) from when the motor 3 starts to decelerate until it stops. With this configuration, extending the stop time until the motor 3 stops reduces the impact on the motorized roller 1 when the motor 3 stops, and prevents damage to the motorized roller 1. This makes it possible to extend the life of the motorized roller 1.

[0054] The motorized roller 1 preferably includes an output unit 21 that outputs details of the abnormality when the abnormality detection unit 18 detects an abnormality in the motorized roller 1. The conveying device 100 shown in Fig. 1 may also include a notification unit (not shown) that can notify a person of the details of the abnormality when the output unit 21 outputs the details. The notification unit has a known configuration that can notify a person of the details of the abnormality.

[0055] The motor control unit 14 , motor drive unit 15 , vibration sensor 16 , analysis unit 17 , abnormality detection unit 18 , memory unit 19 , current sensor 20 and output unit 21 are provided on the circuit board 12 .

[0056] (Method for Detecting Abnormalities in a Motorized Roller) Next, a method for detecting abnormalities in a motorized roller will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the method for detecting abnormalities in a motorized roller.

[0057] The motorized roller anomaly detection method includes an initial vibration value extraction step S1 for frequency-analyzing vibration data from the initial operation of the motorized roller to extract an initial vibration value of a predetermined frequency; a current vibration value extraction step S2 for frequency-analyzing current vibration data of the motorized roller to extract a current vibration value of the predetermined frequency; and an anomaly detection step S3 for comparing at least the initial vibration value with the current vibration value to detect an anomaly in a portion corresponding to the predetermined frequency. According to this method, by comparing the initial vibration value with the current vibration value of the predetermined frequency, an anomaly in a portion corresponding to the predetermined frequency can be detected. This makes it possible to identify the portion of the motorized roller where an anomaly has occurred. As a result, the accuracy of anomaly detection in the motorized roller can be improved.

[0058] The initial vibration value extraction step S1 includes, for example, step S1a of selecting the type of motor and the reduction ratio of the reducer, step S1b of determining the frequency corresponding to each part of the motorized roller 1 whose specifications have been selected, step S1c of initializing the motorized roller 1, and step S1d of analyzing (by Fourier transform, for example) vibration data during the initial operation of the motorized roller 1 to extract the initial vibration value of the frequency (predetermined frequency) determined in step S1b.

[0059] In step S1a, it is preferable to store the selected specifications (motor type and reduction ratio of the reducer) in the storage unit 19 shown in Fig. 2. In step S1b, it is preferable to store, for example, each of the frequencies f1 to f11 shown in Table 1 in the storage unit 19. In step S1d, it is preferable to store the initial vibration value of each frequency in the storage unit 19.

[0060] The current vibration value extraction step S2 includes, for example, step S2a of operating a motorized roller incorporated in a conveying device in a normal manner (operating the conveying device), and step S2c of analyzing the current vibration data (for example, by Fourier transform) and extracting the current vibration value of the frequency (predetermined frequency) determined in step S1b. The current vibration value extraction step S2 includes step S2b of returning the motor to its origin, and step S2c is preferably performed after step S2b. Step S2c is performed when no load is placed on the motorized roller (conveying device), for example, once a day at the start of work.

[0061] The abnormality detection step S3 preferably includes, for example, a first abnormality detection step S3a in which a first abnormality is detected by comparing a current vibration value with an initial vibration value at a frequency that is an integer multiple of the motor rotation frequency of the stator portion; a second abnormality detection step S3b in which a second abnormality is detected by comparing a current vibration value with an initial vibration value at a gear meshing frequency; a third abnormality detection step S3c in which a third abnormality is detected by comparing a current vibration value with an initial vibration value at a predetermined frequency and checking the current flowing through the motor; and a fourth abnormality detection step S3d in which a fourth abnormality is detected by comparing a current vibration value with an initial vibration value at the predetermined frequency and checking the current flowing through the motor.

[0062] In this embodiment, first, in a first abnormality detection step S3a, the current vibration value at a frequency that is an integer multiple of the motor rotation frequency of the stator portion is compared with an initial vibration value. In the first abnormality detection step S3a, a first abnormality is detected if the current vibration value is smaller than the initial vibration value by a predetermined value or more. If a first abnormality is detected, it is preferable to replace or repair the motorized roller 1 during regular maintenance S10.

[0063] The method for detecting an abnormality in a motorized roller preferably includes step S4, in which control is performed to extend the stop time from when the motor starts to decelerate until it stops when a first abnormality is detected. The same applies when a second abnormality is detected (S6).

[0064] The method for detecting an abnormality in a motorized roller preferably includes step S5 of outputting a signal related to the first abnormality (first abnormality signal) when the first abnormality is detected. The same applies to the cases when the second to fourth abnormalities are detected (steps S7 to S9).

[0065] The motorized roller anomaly detection method preferably includes step S11, in which, after extending the motor stop time (S4), the current vibration value at a frequency that is an integer multiple of the motor rotation frequency of the stator portion is again extracted and it is confirmed whether the current vibration value is smaller by at least a predetermined value than the previously extracted current vibration value (e.g., the current vibration value when the first anomaly was detected). If the current vibration value is not smaller by at least the predetermined value, the motor stop time is preferably further extended (S4). This reduces the impact on the motorized roller when the motor stops and prevents damage to the motorized roller. As a result, the life of the motorized roller 1 can be extended. The predetermined value in step S11 may be the same as or different from the predetermined value in step S3a for detecting the first anomaly. Note that the motorized roller anomaly detection method does not have to include step S11. The same applies to the case where a second anomaly is detected (S12).

[0066] For example, if the first abnormality is not detected in the first abnormality detection step S3a, the current vibration value at the gear meshing frequency is compared with the initial vibration value in the second abnormality detection step S3b. In the second abnormality detection step S3b, a second abnormality is detected if the current vibration value is greater than the initial vibration value by a predetermined value or more. If the second abnormality is detected, it is preferable to replace or repair the motorized roller in the regular maintenance S10.

[0067] For example, if the second abnormality is not detected in the second abnormality detection step S3b, the current vibration value is compared with the initial vibration value and the current value flowing through the motor is confirmed in the third abnormality detection step S3c. In the third abnormality detection step S3c, if the current vibration value is smaller than the initial vibration value by a predetermined value or more and if an overcurrent is detected to be flowing through the motor, a third abnormality is detected. If the third abnormality is detected, it is preferable to perform emergency maintenance S20 and replace or repair the motorized roller.

[0068] For example, if the third abnormality is not detected in the third abnormality detection step S3c, the current vibration value is compared with the initial vibration value and the current value flowing through the motor is confirmed in the fourth abnormality detection step S3d. In the fourth abnormality detection step S3d, a fourth abnormality is detected if the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current value flowing through the motor is equal to or smaller than a predetermined current value. If the fourth abnormality is detected, it is preferable to perform emergency maintenance S20 and replace or repair the motorized roller.

[0069] If the fourth abnormality is not detected in the fourth abnormality detection step S3d, the process returns to the current vibration value extraction step S2. In this embodiment, if the fourth abnormality is not detected in the fourth abnormality detection step S3d, the process returns to step S2b, but this is not limiting.

[0070] If the motorized roller that was found to be abnormal in the regular maintenance S10 or emergency maintenance S20 is replaced or repaired, the process returns to step S2a. Note that the first and second abnormalities are less urgent, so the process may return to step S2a after step S11 or step S12.

[0071] An embodiment of the motorized roller will be described with reference to Fig. 5. Fig. 5 is a graph showing the relationship between vibration value and frequency when the motorized roller is abnormally fixed.

[0072] The motorized roller according to the embodiment has a 12-slot brushless motor built in. When the motor rotation speed is 5800 rpm, the motor rotation frequency at the stator is 1160 Hz, and integer multiples of this frequency are 2320 Hz, 3480 Hz, and so on.

[0073] 5, the solid line indicates the vibration value when the motorized roller is fixed to the frame (initial vibration value), and the dashed line indicates the vibration value when the motorized roller is not fixed to the frame (current vibration value). Each vibration value is the vibration value when the motor rotation speed is 5800 rpm.

[0074] As shown in Figure 5, when comparing the initial vibration value with the current vibration value, the current vibration value is smaller than the initial vibration value by a predetermined value (for example, 50% of the initial vibration value) at frequencies (2320 Hz, 3480 Hz) that are integer multiples of the motor rotation frequency (1160 Hz) in the stator part. This shows that if there is a fixation abnormality in the motor-incorporated roller, the current vibration value will be smaller than the initial vibration value by a predetermined value or more at frequencies that are integer multiples of the motor rotation frequency in the stator part.

[0075] [1] As described above, in this embodiment, the motorized roller 1 includes the motor 3, the vibration sensor 16 that outputs vibration data generated by the rotation of the motor 3, the analysis unit 17 that performs frequency analysis on the vibration data to extract vibration values ​​of a predetermined frequency, and the abnormality detection unit 18 that detects abnormalities in a part corresponding to the predetermined frequency by comparing at least an initial vibration value of the predetermined frequency extracted by analyzing vibration data during initial operation with a current vibration value of the predetermined frequency extracted by analyzing current vibration data.

[0076] With this configuration, the abnormality detection unit 18 can detect an abnormality in a part corresponding to a predetermined frequency by comparing the initial vibration value with the current vibration value of the predetermined frequency, thereby making it possible to identify the part of the motorized roller 1 where an abnormality has occurred.

[0077] [2] In addition, in the motor-incorporated roller 1 described in [1] above, it is preferable that the predetermined frequency is an integer multiple of the motor rotation frequency in the stator 34 of the motor 3, and the abnormality detection unit 18 detects the first abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more.

[0078] This configuration makes it possible to detect a first abnormality in the motorized roller 1. This makes it possible to detect, for example, a fixation abnormality in the motorized roller 1. As a result, for example, by detecting a fixation abnormality in the motorized roller 1 early, it is possible to prevent a breakdown in the motorized roller 1 and prevent downtime in the conveyance device 100 in which the motorized roller 1 is installed.

[0079] [3] Furthermore, it is preferable that the motorized roller 1 described in [1] or [2] above is provided with a reducer 4 that reduces the rotational speed of the motor 3, the predetermined frequency is a gear meshing frequency in the reducer 4, and the abnormality detection unit 18 detects the second abnormality when the current vibration value is greater than the initial vibration value by a predetermined value or more.

[0080] This configuration makes it possible to detect a second abnormality in the motorized roller 1. This makes it possible to detect, for example, gear wear of the reducer 4 in the motorized roller 1, which is the second abnormality. As a result, by detecting wear of the gear of the reducer 4 early, for example, the motorized roller 1 can be replaced early, thereby shortening downtime caused by a breakdown of the motorized roller 1.

[0081] [4] Preferably, the motorized roller 1 described in any one of [1] to [3] above is provided with a current sensor 20 that detects the current flowing through the motor 3, and the abnormality detection unit 18 detects the third abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current sensor 20 detects that an overcurrent is flowing through the motor 3.

[0082] This configuration makes it possible to detect a third abnormality of the motorized roller 1. This makes it possible to detect, for example, the third abnormality, that the gears of the reducer 4 (of the planetary gear mechanism 42) are jammed. As a result, for example, by detecting the gears of the reducer 4 being jammed early, it becomes easier to determine whether the motorized roller 1 needs to be replaced.

[0083] [5] Preferably, the motorized roller 1 described in any one of [1] to [4] above is provided with a current sensor 20 that detects the current flowing through the motor 3, and the abnormality detection unit 18 detects the fourth abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current value flowing through the motor 3 is equal to or less than the predetermined current value.

[0084] This configuration makes it possible to detect a fourth abnormality of the motorized roller 1. As a result, for example, by detecting the fourth abnormality, idling of the motorized roller 1, the motorized roller 1 can be replaced early, thereby shortening downtime caused by a breakdown of the motorized roller 1.

[0085] [6] The motorized roller 1 described in any one of [1] to [5] above includes a reducer 4 that reduces the rotational speed of the motor 3, and a current sensor 20 that detects current flowing through the motor 3, and the abnormality detection unit 18: first, detects a first abnormality when the current vibration value at a frequency that is an integer multiple of the motor rotation frequency in the stator 34 of the motor 3 is smaller than the initial vibration value by a predetermined value or more; second, detects a second abnormality when the first abnormality is not detected and the current vibration value at the gear meshing frequency of the reducer 4 is larger than the initial vibration value by a predetermined value or more; third, detects a third abnormality when the second abnormality is not detected and the current vibration value at the predetermined frequency is smaller than the initial vibration value by a predetermined value or more and the current sensor 20 detects that an overcurrent has flowed through the motor 3; Fourth, the fourth abnormality may be detected when the third abnormality is not detected, and when the current vibration value at a predetermined frequency is smaller than the initial vibration value by a predetermined current value or more, and when the current value flowing through motor 3 becomes equal to or less than the predetermined current value.

[0086] [7] Furthermore, the motorized roller 1 described in any one of [1] to [6] above is preferably configured to include a motor control unit 14 that controls the motor 3, and the motor control unit 14 performs control to extend the stop time from when the motor 3 starts to decelerate until it stops when the abnormality detection unit 18 detects the first abnormality or the second abnormality.

[0087] With this configuration, by extending the deceleration time until the motor 3 stops, it is possible to reduce the impact on the motorized roller 1 when the motor 3 stops, and to prevent damage to the motorized roller 1. This makes it possible to extend the life of the motorized roller 1.

[0088] [8] In addition, in the motorized roller 1 described in any one of [1] to [7] above, it is preferable that the current vibration value is a vibration value of a predetermined frequency extracted by analyzing vibration data during the origin return operation of the motor 3.

[0089] According to this configuration, by comparing with the current vibration value at the time of the origin return operation, it is possible to prevent vibrations occurring when the transported object 200 is transported from being included in the vibration value. This makes it possible to improve the accuracy of abnormality detection when comparing the initial vibration value with the current vibration value. This configuration is preferable.

[0090] [9] Furthermore, as in this embodiment, the method for detecting an abnormality in the motorized roller 1 includes an initial vibration value extraction step S1 in which vibration data during initial operation is frequency-analyzed to extract an initial vibration value of a predetermined frequency, a current vibration value extraction step S2 in which current vibration data is frequency-analyzed to extract a current vibration value of the predetermined frequency, and an abnormality detection step S3 in which at least the initial vibration value and the current vibration value are compared to detect an abnormality in a portion of the motorized roller 1 that corresponds to the predetermined frequency.

[0091] According to this method, by comparing the initial vibration value of a predetermined frequency with the current vibration value, it is possible to detect an abnormality in a portion corresponding to the predetermined frequency, thereby making it possible to identify the portion of the motorized roller 1 where an abnormality has occurred.

[0092] The motorized roller and the abnormality detection method thereof are not limited to the configurations and effects of the above-described embodiments. Furthermore, the embodiments can be combined. The motorized roller and the abnormality detection method thereof can be modified in various ways without departing from the spirit and scope of the present invention.

[0093] DESCRIPTION OF SYMBOLS 1...motor-integrated roller, 2...roller tube, 3...motor, 31...output shaft, 32...rotor, 33...bearing, 34...stator, 4...reduction gear, 41...output shaft, 42, 42a, 42b...planetary gear mechanism, 5...power transmission unit, 6...first shaft, 7...second shaft, 8...first side member, 9...second side member, 10, 11...bearing, 12...circuit board, 13...cable, 14...motor control unit, 15...motor drive unit, 16...vibration sensor, 17...analysis unit, 18...abnormality detection unit, 19...storage unit, 20...current sensor, 21...output unit, 100...conveyance device, 101...driven roller, 102...frame, 103...conveyed object detection sensor, 104...conveyance control unit, 105...belt, 200...conveyed object

Claims

1. A motor-integrated roller comprising: a motor; a vibration sensor that outputs vibration data generated by the rotation of the motor; an analysis unit that performs frequency analysis on the vibration data to extract vibration values ​​of a predetermined frequency; and an abnormality detection unit that detects abnormalities in a part corresponding to the predetermined frequency by comparing at least an initial vibration value of the predetermined frequency extracted by analyzing vibration data during initial operation with a current vibration value of the predetermined frequency extracted by analyzing current vibration data.

2. A motorized roller as described in claim 1, wherein the predetermined frequency is an integer multiple of the motor rotation frequency in the stator portion of the motor, and the abnormality detection unit detects a first abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more.

3. A motorized roller as described in claim 1, further comprising a reducer that reduces the rotational speed of the motor, the predetermined frequency being a gear meshing frequency in the reducer, and the abnormality detection unit detecting a second abnormality when the current vibration value is greater than the initial vibration value by a predetermined value or more.

4. A motorized roller as described in claim 1, further comprising a current sensor that detects the current flowing through the motor, wherein the abnormality detection unit detects a third abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current sensor detects that an overcurrent is flowing through the motor.

5. A motorized roller as described in claim 1, further comprising a current sensor that detects the current flowing through the motor, wherein the abnormality detection unit detects a fourth abnormality when the current vibration value is smaller than the initial vibration value by a predetermined value or more and the current value flowing through the motor is equal to or less than the predetermined current value.

6. A motor includes a reducer that reduces the rotational speed of the motor, and a current sensor that detects current flowing through the motor, wherein the abnormality detection unit: first, detects a first abnormality when the current vibration value at a frequency that is an integer multiple of the motor rotational frequency in a stator portion of the motor is smaller than the initial vibration value by a predetermined value or more; second, detects a second abnormality when the first abnormality is not detected and the current vibration value at a gear meshing frequency in the reducer is larger than the initial vibration value by a predetermined value or more; third, detects a third abnormality when the second abnormality is not detected and the current vibration value at the predetermined frequency is smaller than the initial vibration value by a predetermined value or more and the current sensor detects that an overcurrent has flowed through the motor; Fourth, the motorized roller according to claim 1, wherein a fourth abnormality is detected when the third abnormality is not detected, the current vibration value at the predetermined frequency is smaller than the initial vibration value by a predetermined value or more, and the value of the current flowing through the motor is equal to or smaller than a predetermined current value.

7. A motor-integrated roller as described in claim 6, further comprising a motor control unit that controls the motor, wherein the motor control unit performs control to extend the stop time from when the motor starts to decelerate until it stops when the abnormality detection unit detects the first abnormality or the second abnormality.

8. A motorized roller according to any one of claims 1 to 7, characterized in that the current vibration value is a vibration value of the specified frequency extracted by analyzing vibration data during the motor's return-to-origin operation.

9. A method for detecting an abnormality in a motorized roller, comprising: an initial vibration value extraction step of frequency-analyzing vibration data during initial operation to extract an initial vibration value of a predetermined frequency; a current vibration value extraction step of frequency-analyzing current vibration data to extract a current vibration value of the predetermined frequency; and an abnormality detection step of comparing at least the initial vibration value with the current vibration value to detect an abnormality in a portion of the motorized roller corresponding to the predetermined frequency.

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