JP2017161476A - Industrial machinery and abnormality detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial machinery and an abnormality detection method capable of easily determining a trouble cause.SOLUTION: Disclosed industrial machinery includes: a motor; a drive mechanism part; a sensor; and an information analysis part. The drive mechanism part is driven by the motor. The sensor is provided to the drive mechanism part to detect at least acceleration speed. The information analysis part compares a value based on the output from the sensor and at least one of a value based on a previous output from the sensor and a preset reference value.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an industrial machine and an abnormality detection method.

  Problems such as vibration and abnormal movement may occur in the drive mechanism of an industrial machine. Conventionally, when a problem occurs in the drive mechanism, a possible cause is estimated, a countermeasure is taken at a place that seems to be necessary, and an operation for confirming whether the problem is solved is performed. If the problem cannot be resolved, another possible cause is estimated, necessary measures are taken, and an operation to confirm again whether the problem is resolved is performed. That is, at present, a technique is adopted in which the possible causes are crushed one by one and countermeasures are repeated. In such a method, it may take a long time to solve the problem.

JP-A-6-320379 Japanese Patent Publication No. 6-63761

  The problem to be solved by the present invention is to provide an industrial machine and an abnormality detection method capable of facilitating the determination of the cause of a failure.

  The industrial machine of an embodiment has a motor, a drive mechanism part, a sensor, and an information analysis part. The drive mechanism is driven by the motor. The sensor is provided in the drive mechanism unit and detects at least acceleration. The information analysis unit compares a value based on the output of the sensor with at least one of a value based on a past output of the sensor and a preset reference value.

It is a figure which shows the industrial machine of embodiment. It is a block diagram which shows the system configuration | structure of the information analysis part of embodiment. It is a side view which shows the movable range of the moving body of embodiment. It is a figure which shows the tendency of the acceleration when screw loosening arises. It is a figure which shows the tendency of the acceleration when the center shift | offset | difference arises. It is a flowchart which shows an example of the processing flow of the abnormality detection method of embodiment. It is a side view which shows the modification of the industrial machine of embodiment.

Hereinafter, an industrial machine and an abnormality detection method according to embodiments will be described with reference to the drawings.
In the present application, the term “abnormal” is used to mean “different from normal”. On the other hand, the term “failure” is used to mean “unfavorable abnormality”. The “acceleration value” in the present application means “a value indicating the magnitude of acceleration”, and is not limited to a value converted into acceleration [G], but may be a voltage value output from a sensor. The term “past” in the present application means “past normal time”. In the present application, when two values related to acceleration are compared, for example, the values are detected under substantially the same conditions (the speed pattern of the moving body, the weight of the work placed on the moving body, and the like).

First, the configuration of the industrial machine 1 according to the embodiment will be described with reference to FIGS. 1 to 3.
Drawing 1 is a figure showing industrial machine 1 of an embodiment.
As shown in FIG. 1, the industrial machine 1 of this embodiment is, for example, a feed mechanism device including a ball screw, or a machine tool, a molding machine, or an industrial robot including the feed mechanism device. However, the industrial machine 1 is not limited to the above example. The industrial machine 1 only needs to be a device having a drive mechanism unit driven by a motor, and can be widely used in various fields.

  As shown in FIG. 1, the industrial machine 1 of this embodiment includes a base 11, a motor unit 12, a drive mechanism unit 13, a coupling 14, a moving body 15, a sensor 16, an interface 17, and a control device 18.

The base 11 is installed on the installation surface of the industrial machine 1 and supports the drive mechanism unit 13 and the like.
The motor unit 12 includes a motor 21 and a position detector 22. The motor 21 is a drive motor that drives the drive mechanism unit 13. The motor 21 is, for example, a servo motor, but is not limited to this, and may be a motor that rotates at a constant speed when the power is turned on. The position detector 22 is provided in the motor 21 and detects the position of the motor 21. For example, the position detector 22 detects the rotation angle of the motor 21 as the position of the motor 21. The position detector 22 is, for example, an encoder or a resolver, but is not limited thereto.

  The drive mechanism 13 includes a screw shaft 31, a nut 32, a first support 33, a second support 34, and a pair of linear guides 35A and 35B.

The screw shaft 31 is connected to the motor 21 by the coupling 14 and is driven to rotate by the motor 21. The screw shaft 31 has a first end portion 31a connected to the coupling 14 and a second end portion 31b located on the opposite side to the first end portion 31a.
Here, the axial direction Z, the radial direction r, and the circumferential direction θ of the screw shaft 31 are defined. The axial direction Z is a direction substantially parallel to the central axis (axial center) C of the screw shaft 31. The radial direction r is a direction away from the central axis C of the screw shaft 31 radially. The circumferential direction θ is a direction that rotates around the central axis C while maintaining a constant distance from the central axis C of the screw shaft 31.

  The nut 32 penetrates through the screw shaft 31 and is attached to the screw shaft 31. A plurality of balls (not shown) are disposed between the nut 32 and the screw shaft 31. The screw shaft 31, the nut 32, and the ball form an example of a ball screw mechanism. The nut 32 moves linearly along the screw shaft 31 when the screw shaft 31 is rotationally driven by the motor 21.

  The 1st support part 33 has the bearing 41 in which the 1st end part 31a of the screw shaft 31 is inserted, and is supporting the 1st end part 31a of the screw shaft 31 rotatably. Similarly, the 2nd support part 34 has the bearing 41 in which the 2nd end part 31b of the screw shaft 31 is inserted, and is supporting the 2nd end part 31b of the screw shaft 31 rotatably. The first support part 33 and the second support part 34 are fixed to the base 11 by a fixing member 42 (for example, a bolt). The first support part 33 and the second support part 34 may be formed integrally with the base 11.

  The pair of linear guides 35 </ b> A and 35 </ b> B are separately arranged on both sides of the screw shaft 31 in a direction substantially orthogonal to the axial direction Z of the screw shaft 31. The pair of linear guides 35A and 35B support the moving body 15 from below. The linear guides 35 </ b> A and 35 </ b> B are guide portions that guide the moving body 15 along the axial direction Z. The linear guides 35 </ b> A and 35 </ b> B regulate the inclination of the moving body 15 in the circumferential direction θ of the screw shaft 31.

  The moving body 15 is connected to the nut 32. The moving body 15 is, for example, a table on which a workpiece, a part to be transported, and the like are placed, but is not limited thereto. The moving body 15 linearly moves along the screw shaft 31 together with the nut 32 when the screw shaft 31 is rotationally driven by the motor 21. For example, the moving body 15 moves away from the motor 21 along the screw shaft 31 (hereinafter referred to as + Z direction) and approaches toward the motor 21 along the screw shaft 31 (hereinafter referred to as −Z direction). And can be moved.

  The sensor 16 is a sensor that detects an abnormality that occurs in the drive mechanism unit 13. The sensor 16 of the present embodiment includes a first sensor 51 and a second sensor 52. The first sensor 51 is attached to the first support portion 33. The second sensor 52 is attached to the second support portion 34. Each of the first sensor 51 and the second sensor 52 is a sensor capable of detecting at least acceleration. For example, the first sensor 51 detects the acceleration accompanying the vibration of the first support part 33 when the first support part 33 vibrates. The second sensor 52 detects the acceleration accompanying the vibration of the second support part 34 when the second support part 34 vibrates. The first sensor 51 and the second sensor 52 output larger values as the vibration is larger. For example, the first sensor 51 and the second sensor 52 output an analog signal corresponding to the magnitude of vibration, but may output a digital signal instead.

  In the present embodiment, each of the first sensor 51 and the second sensor 52 includes a temperature sensor, a humidity sensor, a pressure sensor, an acceleration sensor, an angular acceleration sensor, a magnetic force sensor, an electronic circuit, and a module (1 It is a micro electro mechanical system (MEMS) sensor that is mounted on a chip component (which may be a single chip component). For example, each of the first sensor 51 and the second sensor 52 is a module in which the above-described various sensors, electronic circuits, and input / output interfaces are provided on one substrate and are integrally molded. Each acceleration sensor of the first sensor 51 and the second sensor 52 is a so-called triaxial acceleration sensor. The acceleration in a first direction substantially parallel to the axial direction Z of the screw shaft 31 and the radial direction r of the screw shaft 31 are approximately. The acceleration in the second direction that is parallel and the acceleration in the third direction that is substantially parallel to the radial direction r of the screw shaft 31 and substantially orthogonal to the second direction are detected.

  The first sensor 51 and the second sensor 52 are not limited to MEMS sensors, and may be ordinary acceleration sensors. Further, one of the first sensor 51 and the second sensor 52 may be omitted. Further, the place where the sensor 16 is attached is not limited to the support portions 33 and 34 but may be another place in the drive mechanism portion 13.

  The interface (human machine interface) 17 includes an input device and receives input from the user. In addition, the interface 17 may include an output device on which a failure analysis result by the control device 18 is displayed.

  The control device (drive mechanism control device) 18 includes, for example, a circuit board provided with a processor such as a CPU (Central Processing Unit) and a memory. The control device 18 notifies the motor 21 of a control instruction via the electrical connection line 61. Further, the control device 18 receives the output of the position detector 22 from the position detector 22 via the electrical connection line 62. Further, the control device 18 receives information input by the user from the interface 17 via the electrical connection line 63. Furthermore, the control device 18 receives the outputs (sensor signals) of the first sensor 51 and the second sensor 52 from the first sensor 51 and the second sensor 52 via the electrical connection lines 64A and 64B. The electrical connection line may be either wired or wireless.

Next, the information analysis unit (signal analysis unit) 70 provided in the control device 18 will be described.
As shown in FIG. 1, the control device 18 of the present embodiment has an information analysis unit 70 that analyzes the outputs of the first sensor 51 and the second sensor 52.
FIG. 2 is a block diagram illustrating a system configuration of the information analysis unit 70 when sensor signals output from various sensors are analog signals.
As illustrated in FIG. 2, the information analysis unit 70 includes a signal input unit 71, a filter unit 72, an A / D conversion unit (analog-digital conversion unit) 73, a signal processing unit 74, and a memory 75.

  The signal input unit 71 receives the outputs (sensor signals) of the first sensor 51 and the second sensor 52 sent via the electrical connection lines 64A and 64B. The signal input unit 71 sends the received outputs of the first sensor 51 and the second sensor 52 (hereinafter referred to as the output of the sensor 16) to the filter unit 72.

  The filter unit 72 filters out the output of the sensor 16 sent from the signal input unit 71 to remove unnecessary components (for example, harmonics) included in the output of the sensor 16. The output of the sensor 16 filtered by the filter unit 72 is sent to the A / D conversion unit 73.

  The A / D converter 73 converts the output of the sensor 16 sent from the filter unit 72 from an analog signal to a digital signal. The output of the sensor 16 converted into a digital signal is sent to the signal processing unit 74.

  The signal processing unit 74 performs digital filter processing on the output of the sensor 16 sent from the A / D conversion unit 73 in some cases, and takes it in as data. The signal processing unit 74 takes in the data, for example, at regular intervals, and stores it in the memory 75 as necessary. As a result, the signal processing unit 74 stores the data obtained from the output of the sensor 16 in the memory 75 when the drive mechanism unit 13 is normal. The data stored in the memory 75 includes, for example, data representing the waveform shape (acceleration values at a plurality of times) of normal acceleration change for each drive pattern of the drive mechanism unit 13.

  The signal processing unit 74 of the present embodiment compares the value based on the newly obtained output of the sensor 16 with the value based on the past output of the sensor 16 stored in the memory 75, so that the drive mechanism unit The presence or absence of 13 abnormalities is determined. Furthermore, when it is determined that the drive mechanism unit 13 has an abnormality, the signal processing unit 74 according to the present embodiment determines a value based on the newly obtained output of the sensor 16 and the past of the sensor 16 stored in the memory 75. The cause of the abnormality of the drive mechanism section 13 is determined by comparing the value based on the output of the drive mechanism 13 with a predetermined calculation process. The specific processing of the signal processing unit 74 will be described later in detail.

  As described above, the memory 75 stores data relating to past outputs of the sensor 16. In addition, the memory 75 stores various reference values used for determining whether or not the drive mechanism unit 13 is abnormal and determining the cause of the abnormality.

Next, the movable range R of the moving body 15 which is a premise for explaining specific processing of the signal processing unit 74 will be described.
FIG. 3 is a side view showing the movable range R of the moving body 15.
As shown in FIG. 3, the movable range R of the movable body 15 is a range in which the movable body 15 can linearly move along the screw shaft 31, and includes a limit position L <b> 1 in the −Z direction and a limit position L <b> 2 in the + Z direction. The range between. Here, the center position M, the first end A1, the second end A2, and the center A3 of the movable range R are defined. The center position M is a center position between the limit position L1 and the limit position L2. The first end A1 is a region in the movable range R that is closer to the limit position L1 than to the central position M. The second end A2 is an area in the movable range R that is closer to the limit position L2 than to the central position M. The central portion A3 is a region between the first end A1 and the second end A2 in the movable range R.

  Moreover, the speed pattern P of the moving body 15 used for the test operation for determining the presence or absence of abnormality will be described. FIG. 4A shows an example of the speed pattern P of the moving body 15. The speed pattern P roughly includes first to fifth sections B1, B2, B3, B4, and B5.

  The first section B1 is a section from 0 second (at the start of operation) to 1 second. In the first section B1, the moving body 15 is stopped at the first end A1 of the movable range R, and the stop position holding state in which the stop position of the moving body 15 is held by the motor 21 is realized. Note that “the stop position of the moving body is held by the motor” means that a control instruction for holding the moving body 15 at a certain position is notified to the motor 21, for example, the position of the moving body 15 is shifted. Means that the motor 21 outputs a torque to return the moving body 15 to the original position.

  The second section B2 is a section between 1 second and 2 seconds. In the second section B2, the industrial machine 1 moves the moving body 15 from the first end A1 of the movable range R to the second end A2. Specifically, the industrial machine 1 moves by accelerating the moving body 15 at a constant acceleration, moving at a constant speed after reaching a certain speed, and decelerating at a constant deceleration after reaching a certain position. The body 15 is moved from the first end A1 to the second end A2.

  The third section B3 is a section between 2 seconds and 3 seconds. In the third section B3, the moving body 15 is stopped at the second end A2 of the movable range R, and the stop position holding state in which the stop position of the moving body 15 is held by the motor 21 is realized.

  The fourth section B4 is a section from 3 seconds to 4 seconds. In the fourth section B4, the industrial machine 1 moves the moving body 15 from the second end A2 of the movable range R to the first end A1. Specifically, the industrial machine 1 moves by accelerating the moving body 15 at a constant acceleration, moving at a constant speed after reaching a certain speed, and decelerating at a constant deceleration after reaching a certain position. The body 15 is moved from the second end A2 to the first end A1.

  The fifth section B5 is a section between 4 seconds and 5 seconds. In the fifth section B5, the moving body 15 is stopped at the first end A1 of the movable range R, and the stop position holding state in which the stop position of the moving body 15 is held by the motor 21 is realized.

  Next, the relationship between the cause of the abnormality that occurs in the drive mechanism unit 13 and the tendency of the acceleration that is detected by the drive mechanism unit 13 when an abnormality occurs due to the cause will be described. In addition, the relationship shown below was newly discovered by the research of the inventors of this application.

First, a case where screw looseness occurs in the drive mechanism unit 13 will be described as an example of an abnormality.
“Screw loosening” as used in the present application means looseness related to a ball screw mechanism (for example, the screw shaft 31, the nut 32, and the ball). For example, the loosening of the screw occurs when the fastening of the fixing member 42 that fixes the first support part 33 and the second support part 34 to the base 11 is loosened, or inside the first support part 33 and the second support part 34. This occurs when the fixing of the screw is loosened, or when the ball disposed between the screw shaft 31 and the nut 32 is worn.

  FIG. 4 is a diagram illustrating a tendency of acceleration detected by the drive mechanism unit 13 when the drive mechanism unit 13 is loosened. In addition, (a) in FIG. 4 shows the speed pattern P of the moving body 15 used for test operation as mentioned above. 4B shows the acceleration value detected by the sensor 16 (for example, the first sensor 51) when the speed pattern P is operated. Specifically, the solid line in the figure indicates the value of acceleration detected by the sensor 16 when there is no abnormality in the drive mechanism unit 13. On the other hand, the broken line in the figure indicates the value of acceleration detected by the sensor 16 when the drive mechanism 13 is loosened. As shown in FIG. 4B, it can be seen that when screw loosening occurs, a larger acceleration is detected than in a normal state.

Next, a case where misalignment occurs in the drive mechanism unit 13 will be described as another example of abnormality.
The “center misalignment” referred to in the present application is a state in which at least a part of the shaft center of the screw shaft 31 is eccentric in the radial direction r with respect to the shaft center of the bearing 41 of the first support portion 33 and the second support portion 34, This means that at least a part of the shaft center of the screw shaft 31 is eccentric in the radial direction r with respect to the shaft center of the nut 32 whose position in the radial direction r is regulated by the linear guides 35A and 35B. When misalignment occurs, a force is generated between the nut 32 whose position in the radial direction r is regulated and the screw shaft 31, and vibration is generated by the force. For example, misalignment occurs when the drive mechanism 13 is assembled or when an overload is applied to the drive mechanism 13 (for example, when the screw shaft 31 is bent).

  FIG. 5 is a diagram illustrating a tendency of acceleration detected by the drive mechanism unit 13 when the drive mechanism unit 13 is misaligned. In addition, (a) in FIG. 5 shows the speed pattern P of the moving body 15 used for test operation. The speed pattern P is the same as the speed pattern P shown in FIG. 5B shows the acceleration value detected by the sensor 16 (for example, the first sensor 51) when the speed pattern P is operated. Specifically, the solid line in the figure indicates the value of acceleration detected by the sensor 16 when there is no abnormality in the drive mechanism unit 13. On the other hand, the broken line in the drawing indicates the acceleration value detected by the sensor 16 when the drive mechanism 13 is misaligned. As shown in FIG. 5 (b), it can be seen that when the misalignment occurs, a larger acceleration is detected than in the normal state.

  Here, with reference to (b) in FIG. 4 and (b) in FIG. 5, the difference in the tendency of the acceleration detected when screw loosening occurs and when misalignment occurs will be described. .

  First, as a first difference, in the case of misalignment, a larger acceleration change rate (acceleration differential value) is detected than in the case of screw loosening (see C1 in FIG. 5). This large acceleration change rate may be detected a plurality of times in one movement of the moving body 15. Note that “one movement” in the present application means a group of operations from acceleration in a stopped state, movement at a constant speed, deceleration, and stop. From another point of view, when the moving body 15 is moving at a constant speed, a large change rate of acceleration may be detected in the case of misalignment compared to the case of screw loosening.

  As a difference between the two eyes, in the case of misalignment, with respect to one constant speed movement, the acceleration value detected at the first time during the constant speed movement (for example, time t1 in FIG. 5), and the like The difference (change amount) from the acceleration value detected at the second time during fast movement (for example, time t2 in FIG. 5) is relatively large (see C2 in FIG. 5). On the other hand, in the case of screw loosening, with respect to one constant speed movement, the acceleration value detected at the first time during the constant speed movement (for example, time t1 in FIG. 4) and the constant speed movement The difference from the acceleration value detected at the second time (for example, time t2 in FIG. 4) is relatively small. The first time (time t1) and the second time (time t2) are times when, for example, vibrations generated during acceleration converge to a stable state. That is, the first time and the second time are determined in a situation where the vibration generated during acceleration converges to a stable state. On the other hand, when the vibration generated at the time of acceleration in the constant speed movement does not converge to a stable state, the speed of the constant speed movement may be reduced and the measurement may be performed again. That is, the first time and the second time may be determined in the constant speed movement at a reduced speed. The first time and the second time are not limited to the above example. For example, the first time is a time at which the movement is made at a constant speed after acceleration (it may be a time when the vibration generated at the time of acceleration does not converge to a stable state), and the second time (time t2) is an acceleration. This is the time when the vibration generated at the time of convergence to a stable state.

  As a third difference, in the case of misalignment, the acceleration value detected when the moving body 15 moves the end portion of the movable range R (the first end portion A1 in the example shown in FIG. 5) moves. And the difference (change amount) between the acceleration value detected during the central movement of the movable body 15 moving through the central portion A3 of the movable range R (see C3 in FIG. 5). On the other hand, in the case of screw loosening, the difference between the acceleration value detected during the end movement and the acceleration value detected during the center movement is relatively small. As used herein, “the moving body moves at the end of the movable range” means that the moving body moves in a state where at least a part of the moving body is positioned at the end of the movable range.

  As a fourth difference, in the case of misalignment, the value of acceleration detected when the first end portion moves when the moving body 15 moves through the first end A1 of the movable range R, and the second value of the movable range R. A difference (amount of change) from the acceleration value detected when the second end portion of the moving body 15 moves along the end A2 is relatively large (see C4 in FIG. 5). On the other hand, in the case of screw loosening, the difference between the acceleration value detected when the first end portion is moved and the acceleration value detected when the second end portion is moved is relatively small.

  As a fifth difference, in the case of misalignment, the acceleration value detected in the stop position holding state in which the stop position of the moving body 15 is held by the motor 21 is relatively large (see C5 in FIG. 5). . On the other hand, in the case of screw loosening, the acceleration value detected in the stop position holding state is relatively small.

  As a sixth difference, in the case of screw loosening, the vibration (acceleration) during the moving of the moving body 15 at a constant speed is generally large as compared with the normal level. That is, an average value of accelerations during a period in which the change in acceleration detected by the sensor 16 is equal to or less than a predetermined width (a period in which there is almost no change in acceleration) while the moving body 15 is moving at a constant speed, The difference is relatively large. On the other hand, in the case of misalignment, the difference between the average value of the acceleration and the average value of the past acceleration is relatively small. The “predetermined width” can be arbitrarily set.

  As a seventh difference, in the case of misalignment, the differential value of the acceleration before and after the acceleration or deceleration of the moving body 15 or the acceleration or deceleration of the mobile body 15 is a positive value and a negative value within a predetermined time difference. (See C7 in FIG. 5). In other words, the differential value of acceleration changes between a positive value and a negative value within a relatively short time. The “predetermined time difference” can be arbitrarily set.

Based on the above, specific processing by the signal processing unit 74 of the present embodiment will be described.
FIG. 6 shows an example of the processing flow of the abnormality detection method executed by the signal processing unit 74.
As shown in FIG. 6, first, the signal processing unit 74 acquires a value based on the output of the sensor 16 (S101). The “value based on the sensor output” referred to in the present application may be a value itself included in the sensor output, or a value obtained by performing arithmetic processing, determination processing, or the like on the sensor output. For example, the “value based on the output of the sensor” referred to in the present application includes an acceleration change rate (differential value of acceleration) obtained by performing arithmetic processing on the output of the sensor, various differential values described later, and the like. Further, “obtaining a value” as used in the present application is not limited to receiving the value itself, but includes a case where the value is calculated by itself based on the received information.

  Then, the signal processing unit 74 first determines whether there is an abnormality in the drive mechanism unit 13. Specifically, the signal processing unit 74 compares the acceleration value newly detected by the sensor 16 with at least one of the acceleration value previously detected by the sensor 16 and a preset reference value BVa ( S102). The reference value BVa is an example of a “first reference value” and can be set arbitrarily. Then, the signal processing unit 74 detects the difference between the acceleration value newly detected by the sensor 16 and the acceleration value detected in the past within a preset range, or is newly detected by the sensor 16. If the acceleration value is equal to or less than the reference value BVa, it is determined that there is no abnormality in the drive mechanism unit 13 (S110). On the other hand, the signal processing unit 74 detects that the acceleration value newly detected by the sensor 16 and the acceleration value detected in the past are different from each other beyond a preset range, or is newly detected by the sensor 16. When the acceleration value is greater than the reference value BVa, it is determined that the drive mechanism unit 13 is abnormal.

  When it is determined that the drive mechanism unit 13 has an abnormality, the signal processing unit 74 of the present embodiment proceeds to a process of determining the cause of the abnormality. The process for determining the cause of the abnormality includes, for example, at least one of seven different determination processes (S103, S104, S105, S106, S107, S108, and S109). Any of these seven types of determination processing is processing for determining whether the cause of the abnormality is misalignment or screw loosening. For this reason, the signal processing unit 74 determines whether the cause of the abnormality is misalignment or screw loosening by executing only one of the following seven types of determination processes. Also good. In addition, the signal processing unit 74 sequentially executes two or more of the following seven types of determination processes, and when it is determined as misalignment in one or more determination processes, the cause of the abnormality as a final determination result May be determined as misalignment. On the other hand, the signal processing unit 74 determines that the cause of the abnormality is screw loosening, for example, when it is not determined as misalignment in all of the one or more determination processes that are executed (S112). The order in which the following seven types of determination processes are executed is not particularly limited.

  For example, the signal processing unit 74 differentiates a value obtained by differentiating acceleration newly detected by the sensor 16 (differential value of acceleration newly obtained) from the acceleration detected by the sensor 16 in the past. Is compared with at least one of the value obtained by (differential value of past acceleration) and a preset reference value BVb (S103). The reference value BVb is an example of a “second reference value” and can be arbitrarily set. For example, the signal processing unit 74 compares a newly obtained differential value of acceleration with a differential value of past acceleration or a preset reference value BVb with respect to one movement of the moving body 15 by a predetermined sampling. Perform multiple times in a cycle. When the signal processing unit 74 determines that the differential value of the newly obtained acceleration and the differential value of the past acceleration are different from each other beyond a preset range in at least one comparison among the plurality of comparisons. If the differential value of the newly obtained acceleration is greater than the reference value BVb, it is determined that the cause of the abnormality is misalignment (S111). Note that the signal processing unit 74 determines that, in two or more comparisons among the plurality of comparisons, the differential value of the newly obtained acceleration and the differential value of the past acceleration differ from each other beyond a preset range. Alternatively, when the differential value of the newly obtained acceleration is larger than the reference value BVb, it may be determined that the cause of the abnormality is misalignment. Further, the differential value of acceleration may be a differential value of acceleration detected when the moving body 15 moves at a constant speed. On the other hand, when the difference between the newly obtained differential value of acceleration and the past differentiated value of acceleration is within a preset range, or the newly obtained differential value of acceleration is used as a reference. When the value is equal to or less than the value BVb, it may be determined that the cause of the abnormality is loose screw (S112).

In addition, the signal processing unit 74 detects the acceleration value detected by the sensor 16 at the first time during the constant speed movement and the sensor at the second time during the constant speed movement with respect to one constant speed movement of the moving body 15. The difference value DVa, which is a difference from the acceleration value detected by the sensor 16, is compared with at least one of the difference value DVa obtained from the past output of the sensor 16 and a preset reference value BVc (S104). The difference value DVa is an example of a “first difference value”. The reference value BVc is an example of a “third reference value” and can be arbitrarily set. The “difference value DVa obtained from the past output of the sensor” refers to the acceleration value at the first time during the past constant speed movement and the acceleration value at the second time during the past constant speed movement. Difference. The definitions of “first time” and “second time” are as described above.
Then, the signal processing unit 74 determines whether the newly obtained difference value DVa and the difference value DVa obtained from the past output of the sensor 16 are different from each other beyond a preset range, or a newly obtained difference. When the value DVa is larger than the reference value BVc, it is determined that the cause of the abnormality is misalignment (S111). On the other hand, when the difference between the newly obtained difference value DVa and the difference value DVa obtained from the past output of the sensor 16 is within a preset range, or the signal processing unit 74 is newly obtained. When the difference value DVa is equal to or less than the reference value BVc, it may be determined that the cause of the abnormality is screw loosening (S112).

Further, the signal processing unit 74 detects the acceleration value detected by the sensor 16 when the moving body 15 moves the end (the first end A1 or the second end A2) of the movable range R, and the movable range. The difference value DVb, which is the difference from the acceleration value detected by the sensor 16 when the moving body 15 moves through the central portion A3 of R, is set in advance as the difference value DVb obtained from the past output of the sensor 16 and the difference value DVb. Compared with at least one of the reference values BVd (S105). The difference value DVb is an example of a “second difference value”. The reference value BVd is an example of a “fourth reference value” and can be set arbitrarily. The “difference value DVb obtained from the past output of the sensor” is a difference between the acceleration value at the past edge movement and the acceleration value at the past center movement.
Then, the signal processing unit 74 determines whether or not the newly obtained difference value DVb and the difference value DVb obtained from the past output of the sensor 16 are different from each other beyond a preset range, or newly obtained difference. When the value DVb is larger than the reference value BVd, it is determined that the cause of the abnormality is misalignment (S111). On the other hand, the signal processing unit 74 determines whether the difference between the newly obtained difference value DVb and the difference value DVb obtained from the past output of the sensor 16 is within a preset range, or newly obtained. When the difference value DVb is equal to or less than the reference value BVd, it may be determined that the cause of the abnormality is loose screw (S112).

In addition, the signal processing unit 74 calculates the acceleration value detected by the sensor 16 when the moving body 15 moves the first end A1 of the movable range R and the second end A2 of the movable range R. The difference value DVc, which is the difference from the acceleration value detected by the sensor 16 during the movement of the second end where the moving body 15 moves, is used as the difference value DVc obtained from the past output of the sensor 16 and a preset reference BVe. Is compared with at least one of them (S106). The difference value DVc is an example of a “third difference value”. The reference value BVe is an example of a “fifth reference value” and can be arbitrarily set. The “difference value DVc obtained from the past output of the sensor” is a difference between the acceleration value during the past movement of the first end portion and the acceleration value during the past movement of the second end portion.
The signal processing unit 74 determines whether or not the newly obtained difference value DVc and the difference value DVc obtained from the past output of the sensor 16 are different from each other beyond a preset range, or a newly obtained difference. When the value DVc is larger than the reference value BVe, it is determined that the cause of the abnormality is misalignment (S111). On the other hand, the signal processing unit 74 determines that the difference between the newly obtained difference value DVc and the difference value DVc obtained from the past output of the sensor 16 is within a preset range or is newly obtained. When the difference value DVc is equal to or less than the reference value BVe, it may be determined that the cause of the abnormality is loose screw (S112).

Further, the signal processing unit 74 detects the acceleration value newly detected by the sensor 16 in the stop position holding state in which the stop position of the moving body 15 is held by the motor 21, and the sensor 16 detects in the past stop position holding state. The acceleration value is compared with at least one of a preset reference value BVf (S107). The reference value BVf is an example of a “sixth reference value” and can be arbitrarily set.
Then, the signal processing unit 74 has a case where the acceleration value newly detected by the sensor 16 in the stop position holding state and the acceleration value detected by the sensor 16 in the past stop position holding state are different beyond a preset range. Alternatively, when the acceleration value newly detected by the sensor 16 in the stop position holding state is larger than the reference value BVf, it is determined that the cause of the abnormality is misalignment (S111). On the other hand, the signal processing unit 74 determines that the difference between the acceleration value newly detected by the sensor 16 in the stop position holding state and the acceleration value detected by the sensor 16 in the past stop position holding state is within a preset range. If the acceleration value newly detected by the sensor 16 in the stop position holding state is equal to or smaller than the reference value BVf, it may be determined that the cause of the abnormality is screw loosening (S112).

Further, the signal processing unit 74 is configured to set an average acceleration value during a period in which the change in acceleration detected by the sensor 16 during the moving body 15 is moving at a constant speed and a predetermined width or less, an average value of the past acceleration, and a preset value. At least one of the reference values BVg is compared (S108). The reference value BVg is an example of a “seventh reference value” and can be arbitrarily set. Note that the “average value of the past acceleration” is an average value of acceleration during a period when the change in acceleration detected by the sensor 16 during the past movement of the moving body 15 at a constant velocity is equal to or less than a predetermined width.
Then, the signal processing unit 74 determines whether or not the newly obtained average value of the acceleration and the past average value of the acceleration differ beyond a preset range, or the newly obtained average value of the acceleration. Is larger than the reference value BVg, it is determined that the cause of the abnormality is screw loosening (S112). On the other hand, when the difference between the average value of the newly obtained acceleration and the average value of the past acceleration is within a preset range, or the newly obtained average value of the acceleration is the reference value BVg. In the following cases, it may be determined that the cause of the abnormality is misalignment (S111).

  Further, the signal processing unit 74 determines whether or not the change in the differential value of acceleration before and after acceleration or deceleration of the moving body 15 shows a positive value or a negative value within a predetermined time difference. (S109). Then, the signal processing unit 74 determines that the cause of the abnormality is misalignment when the differential value of the acceleration shows a positive value and a negative value within a predetermined time difference (S111). For example, the signal processing unit 74 indicates that the differential value of the acceleration indicates a positive value and a negative value within a predetermined time difference, and a value based on the newly obtained output of the sensor 16 (for example, an acceleration value or an acceleration value). ) And the value based on the past output of the sensor 16 (acceleration value or acceleration differential value) differing beyond a preset range, or the value based on the output of the sensor 16 (acceleration value or When the differential value of acceleration) is larger than a preset reference value, it is determined that the cause of the abnormality is misalignment. The reference value may be the same as or different from the reference value BVa. On the other hand, when the differential value of the acceleration does not show a positive value and a negative value within a predetermined time difference, the signal processing unit 74 may determine that the cause of the abnormality is screw loosening (S112). .

  Further, the signal processing unit 74 may perform the following determination process instead of or in addition to the above seven types of determination processes. That is, the signal processing unit 74 is abnormal when the moving body 15 reciprocates the movable range R a plurality of times when the acceleration value or the differential value of the acceleration greatly changes beyond a certain reference value at a specific same position. It may be determined that the cause of misalignment is misalignment.

  The first to seventh reference values and the first to third difference values “first”, “second”,... Are given for convenience in order to distinguish each other. Therefore, the plurality of reference values and the plurality of difference values may be appropriately renumbered as “first”, “second”,. In addition, values obtained by differentiating acceleration detected by the sensor in the past, first to third difference values obtained from past outputs of the sensor, and the like are calculated in advance and stored in the memory 75, for example. However, it may be calculated when the determination process is performed instead.

The industrial machine 1 may perform a test operation including the determination process as described above, for example, during a warm-up operation. For example, in this case, the industrial machine 1 may perform the above-described determination process by comparing the detected value relating to acceleration with the reference values BVa, BVb, BVc, BVd, BVe, BVf, BVg, and the like.
Further, the industrial machine 1 may detect acceleration by the sensor 16 during actual work in which a work or a part is placed on the moving body 15 and sequentially perform the above-described determination processing by the signal processing unit 74. For example, in this case, the industrial machine 1 may perform the above-described determination process by comparing a value related to the detected acceleration with a value related to the past acceleration stored in the memory 75. In this case, information related to the type (or weight) of the work and parts placed on the moving body 15 and the moving conditions of the moving body 15 may be input to the signal processing unit 74 through the interface 17. Thereby, the signal processing unit 74 compares the newly detected value related to the acceleration with the value related to the past acceleration in the case where the type (or weight) of the workpiece or component and the moving condition of the moving body 15 are the same.

  According to such a configuration, the industrial machine 1 that can facilitate the determination of the cause of the failure is provided. That is, the signal processing unit 74 (information analysis unit 70) of the present embodiment uses a value based on the output of the sensor 16 provided in the drive mechanism unit 13 as a value based on the past output of the sensor 16 and a preset reference. Compare with at least one of the values. Thereby, for example, when an abnormality with a relatively large vibration exists in the drive mechanism unit 13, the abnormality can be easily known. As a result, for example, when a problem occurs, the cause of the problem can be narrowed down to several. Thereby, it is possible to facilitate the determination of the cause of the malfunction. In addition, if the method is a method for comparing a value based on the output of the sensor 16 with at least one of a value based on the past output of the sensor 16 and a preset reference value, the device is more expensive than a method using, for example, Fourier analysis. Is no longer needed.

  In the present embodiment, the drive mechanism unit 13 includes a first support portion 33 that rotatably supports the first end portion 31a of the screw shaft 31 and a second support portion that rotatably supports the second end portion 31b of the screw shaft 31. And a support portion 34. The sensor 16 is provided on at least one of the first support portion 33 and the second support portion 34. According to such a configuration, it becomes easy to detect the presence of an abnormality associated with the vibration of the screw shaft 31. For this reason, it is possible to improve the accuracy of determining the cause of the malfunction.

  In the present embodiment, the sensor 16 detects at least the acceleration in the radial direction r of the screw shaft 31. According to such a configuration, vibration in the radial direction r of the screw shaft 31 that is most likely to generate vibration when the abnormality occurs in the screw shaft 31 can be detected with high accuracy. For this reason, it is possible to further improve the accuracy of determining the cause of the malfunction.

  In the present embodiment, at least one determination process is performed among the above-described S103, S104, S105, S106, S107, S108, and S109. According to such a configuration, it is possible to easily determine whether the cause of the failure is screw loosening or misalignment. Thereby, it is possible to further facilitate the determination of the cause of the malfunction.

  In this embodiment, the sensor 16 is a MEMS sensor that can detect acceleration, temperature, and magnetic force with one module and can exchange data by communication. According to such a configuration, the sensor 16 that detects the acceleration of the drive mechanism unit 13 and the sensor that is disposed at another location where the temperature is to be measured by the industrial machine 1 or the magnetic force is disposed at another location. The sensor can be a MEMS sensor of the same standard, and the interface of the control device 18 can be shared (unified). Thereby, the sensor 16 which detects the acceleration of the drive mechanism part 13 can be provided easily cheaply, and the cost reduction of the industrial machine 1 can be aimed at.

  Note that part or all of the signal processing unit 74 of the above-described embodiment is a software function unit that functions when a processor such as a CPU executes a program. Further, part or all of the signal processing unit 74 may be a hardware function unit such as an LSI (Large Scale Integration) or an ASIC (Application Specific Integrated Circuit). The program may be stored in the memory of the control device 18, or may be downloaded from an external device via the Internet facility or the like. Further, part or all of the signal processing unit 74 may be realized by cloud computing via the Internet. The memory 75 is realized by a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), a flash memory, or the like.

  As mentioned above, although the industrial machine 1 which concerns on embodiment was demonstrated, the structure of embodiment is not restricted to the said example. For example, FIG. 7 shows an industrial machine 1 according to a modification. The industrial machine 1 of this modification is a molding machine. For example, the sensor 16 may be provided in the first to third drive mechanism portions 13A, 13B, and 13C of the molding machine. Also with these configurations, it is possible to facilitate the determination of the cause of the failure as in the above embodiment. Note that, in the configuration described below, the same reference numerals are given to configurations having the same or similar functions as the configurations of the above-described embodiment, and descriptions thereof are omitted.

  For example, the molding machine has an injection device 81 for injecting a molten material. The first drive mechanism unit 13 </ b> A is a drive mechanism unit that moves the injection device 81. The first drive mechanism portion 13A includes a screw shaft 31, a holed member 82 through which the screw shaft 31 is passed, a support portion 33 that rotatably supports the screw shaft 31, and a driven pulley 83 attached to the screw shaft 31. And a drive pulley 84 attached to the motor 21, and a driven pulley 83 and a belt 85 stretched around the drive pulley 84. The member 82 with a hole is provided in the injection device 81 and forms an example of a moving body. The screw shaft 31 is rotationally driven by the motor 21 to linearly move the injection device 81 and the holed member 82. The sensor 16 is attached to the support portion 33 and the holed member 82, respectively. That is, the sensor 16 is not limited to a support portion that rotatably supports the screw shaft 31, and may be provided on a moving body that linearly moves when the screw shaft 31 is rotationally driven by the motor 21.

  Further, the molding machine has a moving plate 86 for holding a moving mold. The second drive mechanism unit 13B is a drive mechanism unit (toggle mechanism) that moves the moving plate 86. The second drive mechanism portion 13B includes a screw shaft 31, a link connecting portion 87 through which the screw shaft 31 is passed, a toggle support (support portion) 88 that rotatably supports the screw shaft 31, a driven pulley 83, and a drive. A pulley 84 and a belt 85 are included. The link connecting portion 87 is connected to the moving board 86 via a link and forms an example of a moving body. The screw shaft 31 is rotationally driven by the motor 21 to move the link connecting portion 87 linearly. The sensor 16 is attached to the link connection part 87 and the toggle support 88, respectively.

  The molding machine also has an ejector plate 89 to which ejector pins are attached. The third drive mechanism unit 13 </ b> C is a drive mechanism unit that moves the ejector plate 89. The third drive mechanism portion 13 </ b> C includes a screw shaft 31, an ejector plate 89 through which the screw shaft 31 is passed, a driven pulley 83, a drive pulley 84, and a belt 85. The ejector plate 89 forms an example of a moving body. The screw shaft 31 is rotationally driven by the motor 21 to move the ejector plate 89 linearly. The sensor 16 is attached to the ejector plate 89.

  According to at least one embodiment described above, the industrial machine includes a value based on an output of a sensor provided in the drive mechanism unit, a value based on a past output of the sensor, and a reference value set in advance. Make a comparison. Thereby, it is possible to facilitate the determination of the cause of the malfunction.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Industrial machine, 13 ... Drive mechanism part, 15 ... Moving body, 16 ... Sensor, 21 ... Motor, 31 ... Screw shaft, 31a ... First end of screw shaft, 31b ... Second end of screw shaft, 33 ... 1st support part, 34 ... 2nd support part, 70 ... Information analysis part, R ... Movable range, A1 ... First end part of movable range, A2 ... Second end part of movable range, A3 ... Center of movable range Department.

Claims (16)

A motor,
A drive mechanism driven by the motor;
A sensor that is provided in the drive mechanism and detects at least acceleration;
An information analysis unit that compares a value based on the output of the sensor with at least one of a value based on a past output of the sensor and a preset reference value;
Industrial machine with The drive mechanism includes: a screw shaft that moves the moving body by being rotationally driven by the motor; a first support portion that rotatably supports one end portion of the screw shaft; and the other end portion of the screw shaft. A second support part rotatably supported;
The sensor is provided on at least one of the first support part and the second support part,
The industrial machine according to claim 1. The sensor detects at least radial acceleration of the screw shaft;
The industrial machine according to claim 2. The information analysis unit, as the comparison, the value obtained by differentiating the acceleration detected by the sensor, the value obtained by differentiating the acceleration detected by the sensor in the past, and the preset value Compare with at least one of the reference values,
The industrial machine according to claim 2 or claim 3. As the comparison, the information analysis unit, for the one constant speed movement of the moving body, the acceleration value detected by the sensor at the first time during the constant speed movement and the second time during the constant speed movement. Comparing the difference value with the acceleration value detected by the sensor at least one of the difference value obtained from the past output of the sensor and the reference value set in advance.
The industrial machine according to claim 2 or claim 3. As the comparison, the information analysis unit uses the value of the acceleration detected by the sensor when the moving body moves in the end of the movable range of the moving body and the central portion of the movable range of the moving body as the moving body. Comparing the difference value with the acceleration value detected by the sensor when the sensor moves with at least one of the difference value obtained from the past output of the sensor and the preset reference value;
The industrial machine according to claim 2 or claim 3. The information analysis unit is obtained when the difference value obtained from the sensor output differs from the difference value obtained from the past output of the sensor beyond a preset range, or obtained from the sensor output. When the difference value is larger than the reference value, it is determined that the screw shaft is misaligned.
The industrial machine according to claim 6. As the comparison, the information analysis unit includes, as the comparison, an acceleration value detected by the sensor when the moving body moves in the first end of the movable range of the moving body and a second end of the movable range of the moving body. Comparing the difference value with the acceleration value detected by the sensor when the moving body moves with at least one of the difference value obtained from the past output of the sensor and the reference value set in advance.
The industrial machine according to claim 2 or claim 3. As the comparison, the information analysis unit detects the acceleration value detected by the sensor in the stop position holding state in which the stop position of the moving body is held by the motor, and the sensor detects in the past stop position holding state. Comparing the acceleration value and at least one of the preset reference value,
The industrial machine according to claim 2 or claim 3. As the comparison, the information analysis unit preliminarily sets an average value of acceleration during a period in which the change in acceleration detected by the sensor during the moving body is moving at a constant speed is equal to or less than a predetermined width, and an average value of the past acceleration. Compared to at least one of the reference values, the average value of the acceleration and the average value of the past acceleration differ beyond a preset range, or the average value of the acceleration is more than the reference value When it is large, it is determined that the screw shaft is loose.
The industrial machine according to claim 2 or claim 3. The information analysis unit, as the comparison, the differential value of acceleration before and after acceleration or deceleration of the moving body indicates a positive value and a negative value within a predetermined time difference, When the value based on the sensor output differs from the value based on the past output of the sensor beyond a preset range, or when the value based on the sensor output is larger than the reference value, the screw shaft To determine that there is misalignment
The industrial machine according to claim 2 or claim 3. The sensor is a micro electro mechanical system (MEMS) sensor composed of one module capable of detecting acceleration, temperature, and magnetic force.
The industrial machine according to any one of claims 1 to 11. Obtain a value based on the output of at least an acceleration sensor provided in a drive mechanism unit driven by a motor,
The value is compared with at least one of a value based on a past output of the sensor and a preset reference value.
Anomaly detection method. The drive mechanism includes: a screw shaft that moves the moving body by being rotationally driven by the motor; a first support portion that rotatably supports one end portion of the screw shaft; and the other end portion of the screw shaft. A second support part rotatably supported, and the sensor is provided on at least one of the first support part and the second support part,
As the comparison, the value of the acceleration detected by the sensor when the moving body moves in the end of the movable range of the moving body and the sensor when the moving body moves in the center of the movable range of the moving body. Comparing the difference value with the acceleration value detected by at least one of the difference value and the reference value obtained from the past output of the sensor;
When the difference value obtained from the sensor output and the difference value obtained from the past output of the sensor differ beyond a preset range, or the difference value obtained from the sensor output is the reference When larger than the value, it is determined that the screw shaft is misaligned.
The abnormality detection method according to claim 13. The drive mechanism includes: a screw shaft that moves the moving body by being rotationally driven by the motor; a first support portion that rotatably supports one end portion of the screw shaft; and the other end portion of the screw shaft. A second support part rotatably supported, and the sensor is provided on at least one of the first support part and the second support part,
As the comparison, the average value of the acceleration during the period when the change of the acceleration detected by the sensor while the moving body is moving at a constant speed is equal to or less than a predetermined width, the average value of the past acceleration, and the preset reference value Compared to at least one,
When the average value of the acceleration and the average value of the past acceleration are different from each other beyond a preset range, or when the average value of the acceleration is larger than the reference value, the screw shaft is loosened. To determine,
The abnormality detection method according to claim 13. The drive mechanism includes: a screw shaft that moves the moving body by being rotationally driven by the motor; a first support portion that rotatably supports one end portion of the screw shaft; and the other end portion of the screw shaft. A second support part rotatably supported, and the sensor is provided on at least one of the first support part and the second support part,
A differential value of acceleration before and after acceleration or deceleration of the moving body indicates a positive value and a negative value within a predetermined time difference, and a value based on the output of the sensor and the sensor When the value based on the past output differs beyond a preset range, or when the value based on the output of the sensor is larger than the reference value, it is determined that the screw shaft is misaligned.
The abnormality detection method according to claim 13.

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