JP7322975B2 - Condition monitoring device and condition monitoring method for linear guide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a linear guide condition monitoring device and a condition monitoring method.

Conventionally, there has been known a linear motion guide device (linear guide) having a guide rail, a slider, and a plurality of rolling elements as rolling linear motion elements, in which the slider moves with respect to the guide rail via the rolling elements. ing. As a method for monitoring the state of the linear guide, for example, Patent Documents 1 and 2 disclose a method of detecting vibration of the linear guide using a sensor and detecting an abnormality based on the detected vibration data. .

In Patent Document 1, the data collection time T for capturing the output signal of the sensor is set to be equal to or longer than the period t in which the rolling elements that move back and forth in the endless circulation path enter the load path from the no-load path, and the rolling elements enter and leave the load path. A technique is disclosed for performing condition monitoring in consideration of vibrations that occur when the vehicle is moving.
In addition, Patent Document 2 discloses a technique for constructing a trigger signal for obtaining measurement timing from an acceleration signal obtained from a vibration acceleration sensor, extracting vibration measurement data only during steady-speed operation, and monitoring the state. disclosed.

Japanese Patent No. 6403743 JP 2012-98213 A

However, in the technology described in each of the above patent documents, the slider of the reciprocally movable linear guide extracts part of the vibration data when it is moving in one direction (outward movement or return movement) to monitor the state. It is carried out. Therefore, there is a possibility that the abnormality of the component parts of the linear guide due to position dependency cannot be detected with high accuracy.
In addition, linear guides are used in various types of production equipment such as machine tools, transfer equipment, and injection molding machines. It is desirable to do However, the techniques described in the above patent documents do not take this point into consideration.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a linear guide condition monitoring device and a condition monitoring method capable of appropriately collecting data for more accurately diagnosing the condition of a linear guide.
It is another object of the present invention to provide a linear guide condition monitoring device and method capable of collecting data for diagnosing the condition of a linear guide in-line without affecting production takt time. aim.

In order to solve the above problems, a linear guide condition monitoring device according to one aspect of the present invention monitors the condition of a linear guide having a guide rail, a slider, and a plurality of rolling elements. A device comprising: a drive control section for controlling a drive section so as to move the slider at a constant speed with respect to the guide rail for one reciprocation or more in a no-load state; and a drive control section for controlling the drive section. a data collection unit that collects as data physical quantities related to the linear guide during operation; and an analysis unit that analyzes the data collected by the data collection unit and monitors the state of the linear guide, The analysis unit has a comparison diagnosis unit that diagnoses the state of the linear guide by comparing the analysis results of the forward trip data and the return trip data among the data collected by the data collection unit.
Here, the no-load state refers to a state in which the equipment provided with the linear guide is not processing the work, and the linear guide is not subjected to a load due to the processing. For example, when a processing device such as a machine tool is provided with a linear guide, it refers to a state in which the processing device is not processing a work and the linear guide is not subjected to a load due to processing of the work. In other words, the no-load state mentioned here does not mean a state in which there is no load acting on the linear guide due to the device configuration or product specifications, such as the preload load or the load due to the weight of the table.
In this way, the linear guide is idled at a constant speed for one or more reciprocations, and data is collected during that time. It is possible to collect diagnostic data that can detect, for example, more accurately.
In addition, since it is equipped with an analysis unit, it is possible to use the collected data to detect with a high degree of accuracy an abnormality in the components of the linear guide due to position dependency (for example, damage to the guide rail or slider). , Planned preventive maintenance can be performed.
In addition, the comparative diagnosis unit makes it possible to make an appropriate diagnosis by utilizing the fact that the data in the linear guide changes between the outward and return trips. It can be performed.

Further, in the linear guide condition monitoring device, the drive control unit may include a section in which the slider moves in a loaded state during operation of equipment including the linear guide in the movement section in which the slider is moved. good.
For example, when a processing device such as a machine tool is provided with a linear guide, an abnormality such as part damage is likely to occur in a section where the slider travels during processing. By including the section in which the slider travels during processing in the section in which data is collected, it is possible to appropriately perform abnormality detection.

In the linear guide condition monitoring device described above, the drive control section may have a drive condition storage section that stores drive conditions for periodically controlling the drive section under the same conditions.
In this case, the collected data can be arranged in chronological order and trends can be monitored. Therefore, when the state changes due to the occurrence of an abnormality or the like, it can be appropriately detected. In addition, by collecting data under the same conditions each time, diagnostic accuracy can be improved.

Further, in the linear guide condition monitoring device described above, the analysis unit divides the data collected by the data collection unit into a plurality of data, and based on the analysis result of the divided data, determines the abnormal occurrence location of the linear guide. You may have an abnormal part identification part which identifies.
In this case, since it is possible to specify where in the linear guide the abnormality has occurred, it is possible to quickly perform maintenance of the linear guide.

In order to solve the above problems, a linear guide condition monitoring device according to one aspect of the present invention monitors the condition of a linear guide having a guide rail, a slider, and a plurality of rolling elements. a period acquisition unit that acquires, as a data collection period, a period during which the slider is moving at a constant speed in one direction with respect to the guide rail in an unloaded state within an operation cycle of the linear guide; a data acquisition unit configured to acquire physical quantities relating to the linear guide during the data acquisition period acquired by the period acquisition unit as data ; Acquire as a collection period .
Here, the no-load state refers to a state in which the equipment provided with the linear guide is not processing the work, and the linear guide is not subjected to a load due to the processing. For example, when a processing device such as a machine tool is provided with a linear guide, it refers to a state in which the processing device is not processing a work and the linear guide is not subjected to a load due to processing of the work. In other words, the no-load state mentioned here does not mean a state in which there is no load acting on the linear guide due to the device configuration or product specifications, such as the preload load or the load due to the weight of the table.
In this way, within the operation cycle or operation pattern of the linear guide, the period during which the slider is moving in one direction at a constant speed in an unloaded state is defined as the data collection period, and the data during that period is collected. Data can be collected for diagnosing the condition of the linear guide inline without affecting the time.
In addition, since the period during which the linear guide returns to the origin is acquired as the data collection period, the slider moves to return to the predetermined position immediately after the equipment is started, when the tool is replaced, or when the workpiece is replaced. data can be collected.

In order to solve the above problems, a linear guide condition monitoring device according to one aspect of the present invention monitors the condition of a linear guide having a guide rail, a slider, and a plurality of rolling elements. a period acquisition unit that acquires, as a data collection period, a period during which the slider is moving at a constant speed in one direction with respect to the guide rail in an unloaded state within an operation cycle of the linear guide; and a data collection unit that collects, as data, the physical quantity related to the linear guide during the data collection period that is acquired by the period acquisition unit, wherein the period acquisition unit adds a lubricant during a greasing cycle of the linear guide . The period during which the lubricant is stirred after replenishment is acquired as the data collection period .
In this way, within the operation cycle or operation pattern of the linear guide, the period during which the slider is moving in one direction at a constant speed in an unloaded state is defined as the data collection period, and the data during that period is collected. Data can be collected for diagnosing the condition of the linear guide inline without affecting the time.
Specifically, after replenishing the lubricant (grease, oil), it is possible to collect data when the vehicle is run for a predetermined distance at a constant speed in order to agitate the lubricant.

Further, in the linear guide state monitoring device described above, the period acquisition unit moves the slider in a load state during the operation of equipment including the linear guide in the movement section in which the slider moves during the data collection period. Intervals may be included.
For example, when a processing device such as a machine tool is provided with a linear guide, an abnormality such as part damage is likely to occur in a section where the slider travels during processing. By including the section in which the slider travels during processing in the section in which data is collected, it is possible to appropriately perform abnormality detection.

Further, in the linear guide condition monitoring device described above, the period acquisition unit may periodically acquire the data collection period under the same conditions.
In this case, the collected data can be arranged in chronological order and trends can be monitored. Therefore, when the state changes due to the occurrence of an abnormality or the like, it can be appropriately detected. In addition, taking into consideration that the physical quantity (e.g., vibration) related to the linear guide differs between the forward and return passes, data can be collected when the slider is moving in the same direction each time, which improves diagnostic accuracy. can.

The linear guide condition monitoring device may further include an analysis unit that analyzes the data collected by the data collection unit and monitors the state of the linear guide.
In this case, data collected in-line can be used to properly monitor the condition of the linear guide.

Further, in the linear guide condition monitoring device described above, the analysis unit divides the data collected by the data collection unit into a plurality of data, and based on the analysis result of the divided data, determines the abnormal occurrence location of the linear guide. You may have an abnormal part identification part which identifies.
In this case, since it is possible to specify where in the linear guide the abnormality has occurred, it is possible to quickly perform maintenance of the linear guide.
Furthermore, in the linear guide condition monitoring device described above, the physical quantity may be vibration in a direction orthogonal to the moving direction of the slider. In this case, vibration generated in the slider can be detected appropriately.
The linear guide condition monitoring device further includes a vibration sensor for detecting the vibration data, and the vibration sensor is connected to the slider or the slider and is movable with respect to the guide rail together with the slider. It may be fixed to the moving member. In this case, the physical information of the object to be monitored can be directly collected by the vibration sensor, so highly accurate state monitoring is possible.

Furthermore, the above linear guide condition monitoring device may further include a servomotor for driving the linear guide, and the physical quantity may be at least one of torque and current of the servomotor.
In this case, it is only necessary to detect the torque and current of the servomotor, so there is no need for complicated wiring for installing sensors for detecting physical quantities relating to the linear guide.

According to another aspect of the present invention, there is provided a linear guide state monitoring method for monitoring the state of a linear guide having a guide rail, a slider, and a plurality of rolling elements. a control step of controlling a drive unit to move the slider at a constant speed with respect to the guide rail for one or more reciprocations under load; and an analysis step of analyzing the collected data and monitoring the state of the linear guide. and a comparative diagnosis step of diagnosing the state of the linear guide by comparing the analysis result with the data of
In this way, the linear guide is idled at a constant speed for one or more reciprocations, and data is collected during that time. It is possible to collect diagnostic data that can detect, for example, more accurately.

According to another aspect of the present invention, there is provided a linear guide state monitoring method for monitoring the state of a linear guide having a guide rail, a slider, and a plurality of rolling elements, comprising: an acquiring step of acquiring, as a data collection period, a period during which the slider is moving at a constant speed in one direction with respect to the guide rail in an unloaded state within an operation cycle of the linear guide; a collecting step of collecting physical quantities related to the linear guide as data , wherein the obtaining step obtains a period during which the linear guide returns to the origin as the data collecting period .
Further, a linear guide state monitoring method according to one aspect of the present invention is a linear guide state monitoring method for monitoring the state of a linear guide having a guide rail, a slider, and a plurality of rolling elements, comprising: an acquiring step of acquiring, as a data collection period, a period during which the slider is moving at a constant speed in one direction with respect to the guide rail in an unloaded state within an operation cycle of the linear guide; and a collecting step of collecting physical quantities related to the linear guide as data, wherein in the obtaining step, the data collecting period is defined as a period during which the lubricant is stirred after the lubricant is supplied in the lubrication cycle of the linear guide. to get as
In this way, within the operation cycle or operation pattern of the linear guide, the period during which the slider is moving in one direction at a constant speed in an unloaded state is defined as the data collection period, and the data during that period is collected. Data can be collected for diagnosing the condition of the linear guide inline without affecting the time.

According to one aspect of the present invention, since the linear guide is idled for one or more reciprocations at a constant speed, it is possible to appropriately collect data for more accurately diagnosing the state of the linear guide.
Further, according to one aspect of the present invention, data for diagnosing the state of the linear guide can be collected in-line without affecting production tact time.

FIG. 1 is a diagram showing a schematic configuration of a system including a state monitoring device according to the first embodiment. FIG. 2 is a diagram showing an example of a linear guide. FIG. 3 is a functional block diagram of the condition monitoring device of the first embodiment. 4A and 4B are diagrams for explaining a method of specifying an abnormality occurrence location according to the first embodiment. FIG. FIG. 5 is a diagram showing a schematic configuration of a system including a state monitoring device according to the second embodiment. FIG. 6 is a functional block diagram of the condition monitoring device of the second embodiment. FIG. 7 is a diagram for explaining a method of specifying an abnormality occurrence location according to the second embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention.

(First embodiment)
A first embodiment of the present invention will be described below.
FIG. 1 is a diagram showing a schematic configuration of a system including a state monitoring device 20 that monitors the state of a linear guide 10. As shown in FIG.
As shown in FIG. 1 , the linear guide 10 includes guide rails 1 and sliders 2 . The slider 2 is mounted on the guide rail 1 extending linearly so as to be movable along the longitudinal direction of the guide rail 1 .
In this embodiment, the case where the linear guide 10 is driven by a ball screw (not shown) having a guide rail to which the rotating shaft of the servomotor 11 is connected through a coupling will be described. The driving portion of the linear guide 10 is not limited to a ball screw, and may be configured to be driven by a linear motor, for example.

FIG. 2 is a diagram showing an example of the linear guide 10. As shown in FIG.
The guide rail 1 of the linear guide 10 is made of a substantially quadrangular prism-shaped metal member, and as shown in FIG. It is made up of books.
The slider 2 includes a slider body 2a and end caps 2b attached to both longitudinal ends of the slider body 2a.

The slider body 2a is made of a metal member that extends in the longitudinal direction of the guide rail 1 and has a substantially U-shaped cross section. In the portion of the slider body 2a facing both side surfaces of the guide rail 1, that is, on the inner side surfaces of the legs on both sides, rolling grooves (raceway surfaces) 2c extending in the longitudinal direction facing the raceway surface 1a of the guide rail 1 are formed. Two are formed.
The raceway surface 1a of the guide rail 1 and the raceway surface 2c of the slider body 2a form a rolling path on which the rolling elements 3 roll.

Two straight return passages 2d are formed in the leg portions on both sides of the slider body 2a so as to extend through the slider body 2 in the longitudinal direction in parallel with the track surface 2c. The return path 2d is for returning the rolling element 3 from the end point of the rolling path to the starting point.
The end cap 2b is made of a substantially U-shaped resin member. On the surface of the end cap 2b on the side of the slider body 2a, two direction changing paths 2e are formed on each of the legs on both sides. The direction changing path 2e is for connecting the rolling path and the return path 2d, and has a semicircular arc shape. Note that the end cap 2b is not limited to being made of resin, and may be made of metal.

The rolling elements 3 circulate through the rolling path formed by the raceway surface 1a of the guide rail 1 and the raceway surface 2c of the slider body 2a, the return path 2d of the slider body 2a, and the direction change path 2e of the end cap 2b. A circulation route is configured. A large number of rolling elements 3 are loaded in the circulation path, and the slider 2 moves relative to the guide rail 1 via the rolling elements 3 that roll in the rolling path of the circulation path. there is That is, of the circulation path, the rolling path formed by the raceway surface 1a of the guide rail 1 and the raceway surface 2c of the slider body 2a constitutes a load area in which the rolling elements 3 can receive an external load. The return path 2c and the turning path 2e of the end cap 2b form a no-load area.
Here, the rolling element 3 receives a load from an external load or preload applied to the linear guide 10 in the rolling path, and is made of a spherical metal member. The material of the rolling elements 3 is not limited to metal, and may be ceramics or the like. Moreover, the rolling elements 3 provided in the linear guide 10 are not limited to spherical shapes, and may be rollers.

In this embodiment, a case where the linear guide 10 is applied to a processing device such as a machine tool will be described.
As shown in FIG. 1, the slider 2 of the linear guide 10 is connected to a table 12 on which a workpiece W to be processed is placed. This table 12 can reciprocate along the axial direction of the guide rail 1 together with the slider 2 . By moving the table 12, a desired position of the workpiece W can be machined with a tool 30 such as a cutting tool.

A vibration sensor 14 is fixed near the slider 2 . Specifically, the vibration sensor 14 is fixed to the lower surface of the table 12 as close to the slider 2 as possible. The vibration sensor 14 detects vibration in a direction perpendicular to the traveling direction (axial direction) of the slider 2 as a physical quantity relating to the linear guide 10 .
The position where the vibration sensor 14 is fixed is not limited to the above. Also, the physical quantity related to the linear guide 10 detected by the vibration sensor 14 may be vibration of the slider 2 in the axial direction. However, the vibration in the direction orthogonal to the axial direction of the slider 2 is preferable as a physical quantity related to the linear guide 10 .
Vibration data (vibration data) detected by the vibration sensor 14 is output to the state monitoring device 20 .

The state monitoring device 20 can be configured by, for example, a microcomputer. The state monitoring device 20 includes a CPU 20a, a ROM 20b, a RAM 20c, and a display section 20d. The CPU 20a loads, for example, necessary programs from the ROM 20b to the RAM 20c, and executes the programs to realize various functional operations. Specifically, the CPU 20 a implements a monitoring function operation for monitoring the state of the linear guide 10 based on vibration data obtained from the vibration sensor 14 . The display unit 20d includes a display monitor such as a liquid crystal display.

FIG. 3 is a functional block diagram showing the configuration of the state monitoring device 20. As shown in FIG.
As shown in FIG. 3 , the state monitoring device 20 includes a signal acquisition section 21 , a drive control section 22 , a data collection section 23 , a storage section 24 , an analysis section 25 and an output section 26 . The function of each part shown in FIG. 3 is realized by executing a predetermined program by the CPU 20a shown in FIG.
The signal acquisition unit 21 acquires a trigger signal from the facility side. Here, the trigger signal is output from the equipment side at a timing when the work W is not processed, such as before or after the work W is processed.

The drive control unit 22 controls the servo motor 11 shown in FIG. 1 at the timing when the signal acquisition unit 21 acquires the trigger signal, and drives the linear guide 10 in the diagnostic mode. In the diagnosis mode, the linear guide 10 is idled at a constant speed for one reciprocation or more. Here, idle operation means moving the slider 2 with respect to the guide rail 1 in a no-load state in which the work W is not processed. That is, in the diagnostic mode, the drive control unit 22 moves the slider 2 at a constant speed with respect to the guide rail 1 for one reciprocation or more in the no-load state.
Here, the no-load state refers to a state in which the processing apparatus is not processing the workpiece and the linear guide 10 is not subjected to a load due to the processing of the workpiece. In other words, the no-load state referred to here does not mean a state in which there is no load acting on the linear guide 10 due to the device configuration or product specifications, such as the preload load or the load due to the weight of the table 12 .
The larger the number of reciprocations of idle operation, the more the amount of data to be collected, and the noise component can be reduced by averaging. As the number of round trips increases, the accuracy of condition monitoring can be improved. Also, from the viewpoint of the SN ratio, it is desirable that the moving speed of the slider 2 is 5 m/min or more.

Further, as a condition of idle operation, the slider 2 moves in a load state during the operation of the facility equipped with the linear guide 10, that is, the slider 2 moves during processing of the workpiece W in the processing apparatus. Intervals (processing intervals) can be included. It should be noted that the longer the moving distance of the slider 2 is, the more the amount of data to be collected increases, and the noise component can be reduced by averaging. Therefore, the longer moving distance is desirable. The accuracy of condition monitoring can be improved as the movement distance increases.
After causing the linear guide 10 to idle under the predetermined conditions as described above, the drive control unit 22 terminates the diagnosis mode.

The data collecting unit 23 starts collecting vibration data detected by the vibration sensor 14 at the timing when the trigger signal is obtained by the signal obtaining unit 21 . That is, the data collection unit 23 collects vibration data in synchronization with the idling of the linear guide 10 .
It should be noted that the data collection unit 23 ends data collection of vibration data when the diagnostic mode is ended by the drive control unit 22 .
The storage unit 24 stores the vibration data collected by the data collection unit 23 in a predetermined storage area.

In this embodiment, the condition monitoring device 20 periodically drives the linear guide 10 in diagnostic mode and collects vibration data. At this time, the conditions for collecting vibration data (driving pattern, sampling time, data collection time, etc.) are the same each time. As shown in FIG. 3, the drive control unit 22 has a drive condition storage unit 22a for storing conditions such as the operation pattern. It controls the motor 11 .
In consideration of data stability, it is desirable to collect data in a warm-up state. Also, in order to properly grasp the occurrence of anomalies, it is desirable that the data collection interval is at least once a day in the working days.

The analysis unit 25 analyzes vibration data collected while the linear guide 10 is being driven in the diagnosis mode, and monitors the state of the linear guide 10 .
The output unit 26 outputs the state of the linear guide 10 diagnosed by the analysis unit 25 to the display unit 20d shown in FIG. 1 to present the diagnosis result to the user.

The analysis unit 25, for example, calculates a feature value based on the collected vibration data, and compares the calculated feature value with a reference value to diagnose the state of the linear guide 10 (whether or not an abnormality has occurred, etc.). . Here, the feature value can include at least one of an RMS value, an overall value (OA value), a partial overall value (POA value), a crest factor (CF), and a kurtosis. Note that the feature value is not limited to the above, and can be selected as appropriate. Further, if a threshold value of the feature value is set in advance as the reference value, an abnormality can be easily and appropriately detected by comparing the feature value and the threshold value.

When analyzing the vibration data, the analysis unit 25 divides the vibration data into an outward travel portion, an inward travel portion, an outward and inward processing section portion, and a portion outside the outward and inward processing section, and analyzes each vibration data analysis result ( For example, the above characteristic values) may be compared.
For example, as shown in FIG. 3, the analysis unit 25 may include a comparison diagnosis unit 25a, an abnormal location identification unit 25b, and a determination unit 25c. In this case, the comparison diagnosis unit 25a may compare the analysis results of the divided vibration data, and the determination unit 25c may determine the state of the linear guide 10 based on the comparison result by the comparison diagnosis unit 25a.

By comparing the feature value calculated from the vibration data of the forward trip and the feature value calculated from the vibration data of the return trip, it is possible to confirm the variation of the vibration data.
In the linear guide 10, vibration occurs due to the rolling elements 3 rolling on the rolling path, and due to the rolling elements 3 moving in and out of the load area and unload area of the circulation path. In the linear guide 10, the position at which the rolling element shifts from the load area to the no-load area and the position at which the rolling element shifts from the no-load area to the load area are reversed depending on the direction in which the slider 2 moves. In other words, the excitation position is different between the outward trip and the return trip. Therefore, the same vibration data is not measured on the outward trip and the return trip.
Therefore, by comparing the characteristic values of the outward and return trips by the comparative diagnosis unit 25a shown in FIG. It is possible to perform highly accurate condition monitoring with suppressed diagnosis.

Further, by comparing the feature value calculated from the vibration data in the machining section and the feature value calculated from the vibration data outside the machining section, it is possible to grasp the deterioration or damage state of the machining section.
In general, in the linear guide 10, anomalies tend to occur in the machining section where a load is applied. Therefore, if it is predetermined that an abnormality occurs only in the machining interval and does not occur outside the machining interval (that is, the normal value), the feature value of the machining interval and the feature value (normal value) outside the machining interval can be compared. By simply comparing , the state can be easily confirmed even without the time-series data of the feature values. That is, the comparison diagnosis unit 25a shown in FIG. 3 may compare the feature values of the machining section and the feature values outside the machining section.

Furthermore, the analysis unit 25 may divide the vibration data of the entire region into a plurality of sub-section data, and compare the analysis results (for example, feature values) of the divided vibration data. This makes it possible to identify the position where the state changes. For example, if the rolling surface of the guide rail 1 is scratched at one location, the characteristic value changes when the slider 2 passes through that spot.
FIG. 4 shows an example of characteristic values when the rolling surface of the guide rail 1 is damaged at one location. FIG. 4 shows characteristic values for one reciprocation. Each point (dot) in FIG. 4 is a characteristic value calculated from the vibration data of each divided sub-section. As described above, when there is a scratch on the rolling surface of the guide rail 1 at one location, it is possible to confirm a location (peak) where the characteristic value greatly varies between the outward and return travels. Therefore, by specifying the location where the characteristic value fluctuates, it is possible to specify the position where the guide rail 1 is damaged (abnormal location).
The abnormal location identification unit 25b shown in FIG. 3 divides the vibration data of the entire region into a plurality of data as described above, and identifies the abnormal location of the linear guide 10 based on the analysis result of the divided data. good too.

Furthermore, when the rolling surface of the guide rail 1 is damaged at one location as described above, there is always a peak of the characteristic value on the outward and return paths. Therefore, if there is a characteristic value peak only in either one of the outward path and the return path, it can be determined that there is a measurement error. In this way, by comparing the vibration data of the outward trip and the return trip, it is possible to improve the diagnosis accuracy.
That is, the comparative diagnosis unit 25a shown in FIG. 3 compares the vibration data of the outward trip and the return trip, and the judgment unit 25c compares the vibration data of the outgoing trip and the return trip in the comparative diagnosis unit 25a with the result of the comparison of the vibration data of the outgoing trip and the return trip in the comparison diagnosis unit 25a. It may be determined whether the detected characteristic value peak is due to an error in measurement or due to the occurrence of an abnormality in the guide rail 1, based on the detected abnormality occurrence location.
Since the position to be vibrated by the collision of the rolling elements is changed between the outward trip and the return trip, it is desirable to consider the difference.

In addition, the analysis unit 25 arranges in time series the feature values calculated from the vibration data divided into the outward trip, the return trip, the processing section, and the non-processing section, and monitors the change in tendency, thereby diagnosing the state of the linear guide 10. You may make it In this case, the state of the linear guide 10 can be diagnosed with higher accuracy.
In addition, the analysis unit 25 may arrange characteristic values calculated without dividing the vibration data into outward travel, return travel, processing section, and non-processing section in chronological order to monitor changes in trends. In this case, the accuracy of state monitoring is inferior, but the calculation can be simplified and the memory required for analysis can be reduced.

In the present embodiment, the case where the state monitoring device 20 includes the units shown in FIG. 3 has been described. may be provided. In this case, the state monitoring device 20 transmits the data collected by the data collecting unit 23 to a device different from the state monitoring device 20, and the device different from the state monitoring device 20 analyzes the data to determine the state of the linear guide 10. can diagnose.

As described above, the condition monitoring device 20 according to the present embodiment controls the servo motor 11 so as to move the slider 2 at a constant speed with respect to the guide rail 1 for one reciprocation or more in a no-load state. The guide 10 is driven in diagnostic mode, and vibration data during that period is collected as data for monitoring the state of the linear guide 10 .
In this way, since the condition monitoring device 20 can drive the linear guide 10 in the diagnostic mode, during a series of operation cycles (during the machining cycle), there is no idling operation of one or more round trips at a constant speed. Even if it is, data can be collected appropriately. In addition, since the vibration data is collected not during machining but during idling, it is possible to collect vibration data that minimizes the influence of disturbances that occur during machining. In addition, since the idle operation is one reciprocation or more, the accuracy of state monitoring can be improved. In addition, since the device is idled at a constant speed, stable data measurement can be performed.

Furthermore, the movement section of idle operation can include a section in which the slider 2 of the linear guide 10 moves when processing is performed. As a result, the collected vibration data can include a signal when the vehicle moves through a location where anomalies are likely to occur. Therefore, for example, by comparing the feature value calculated from the vibration data of the machining section and the feature value calculated from the vibration data outside the machining section, it is possible to grasp the deterioration or damage state of the machining section. In this way, anomaly detection can be performed appropriately.

Here, the movement section and the movement distance of idle operation can be set based on predetermined parameters (processing section, etc.) such as the operation cycle of the linear guide 10 and the type of the linear guide 10 .
For example, as in the technique described in Patent Document 1, when the data collection time is set to be equal to or longer than the passing period of the rolling elements, a system for grasping the passing period of the rolling elements is required. On the other hand, in the present embodiment, it is not necessary to separately construct a complicated system for grasping the parameters necessary for setting the dry running conditions.

In addition, in the present embodiment, the linear guide 10 is periodically driven under the same conditions to collect vibration data, thereby arranging the collected vibration data in chronological order and monitoring the tendency thereof. Therefore, when the state changes due to the occurrence of an abnormality or the like, it can be appropriately detected. At this time, since the vibration data is collected under the same conditions every time, the diagnostic accuracy can be improved.
For example, when constructing a trigger from an acceleration signal as in the technique described in Patent Literature 2, it is not always possible to collect data under the same conditions each time. In this embodiment, data is collected when the linear guide 10 is driven in a predetermined diagnosis mode, so data under the same conditions can be collected each time.

As described above, in the present embodiment, the measurement values obtained when the slider is idled at a constant speed for one or more reciprocations are used to detect damage to the guide rail 1, damage to the slider 2, etc., based on position dependency. It is possible to precisely detect which part of the linear guide 10 is damaged, and to perform planned preventive maintenance.

(Second embodiment)
Next, a second embodiment of the invention will be described.
In the above-described first embodiment, the case of diagnosing the state of the linear guide 10 using the measurement value when the slider 2 is moved at a constant speed with respect to the guide rail 1 for one reciprocation or more in a no-load state. explained. In this second embodiment, within a predetermined operation cycle or operation pattern, using the measured value during the period in which the slider 2 is moving in one direction with respect to the guide rail 1 at a constant speed in a no-load state, A case of diagnosing the state of the linear guide 10 will be described.

FIG. 5 is a diagram showing a schematic configuration of a system including a condition monitoring device 20A according to the second embodiment.
The hardware configuration of this state monitoring device 20A is the same as the hardware configuration of the state monitoring device 20 shown in FIG.

FIG. 6 is a functional block diagram showing the configuration of the condition monitoring device 20A in the second embodiment.
As shown in FIG. 6, the condition monitoring device 20A includes a signal acquisition section 21, a data collection section 23, a storage section 24, an analysis section 25, and an output section 26. The function of each part shown in FIG. 6 is realized by executing a predetermined program by the CPU 20a shown in FIG. Here, some of the functions of the units shown in FIG. 6 are different from the functions of the units of the condition monitoring device 20 shown in FIG.

The signal acquisition unit 21 acquires a trigger signal from the facility side. Here, the trigger signal is a signal that indicates a period during which the slider 2 is moving at a constant speed in one direction with respect to the guide rail 1 in an unloaded state within the operation cycle or operation pattern of the linear guide 10 .
Here, the no-load state refers to a state in which the processing apparatus is not processing the workpiece and the linear guide 10 is not subjected to a load due to the processing of the workpiece. In other words, the no-load state referred to here does not mean a state in which there is no load acting on the linear guide 10 due to the device configuration or product specifications, such as the preload load or the load due to the weight of the table 12 .

The linear guide 10 performs an operation (origin return) to return to the origin position at the timing when the equipment is started, the timing when the tool 30 is replaced, the timing when the work W is replaced, and the like. Therefore, the signal acquisition unit 21 may acquire, for example, a trigger signal indicating a period during which the linear guide 10 returns to the origin.
Further, the linear guide 10 has a lubrication cycle, and after lubrication (grease, oil) is replenished, the linear guide 10 may be run at a constant speed for a predetermined distance in order to agitate the lubrication. Therefore, the signal acquisition unit 21 may acquire, for example, a trigger signal indicating that the lubrication cycle is in progress.

For example, the signal acquisition unit 21 moves the slider 2 in one direction with respect to the guide rail 1 in a no-load state within the operation cycle or operation pattern of the linear guide 10 for a certain period from the timing at which the trigger signal is received. It is possible to obtain a period during which the object is moving at a constant speed as a data collection period. The signal acquisition unit 21 may acquire the data collection period by receiving a trigger signal indicating the start timing of the data collection period and a trigger signal indicating the end timing of the data collection period. In this embodiment, the signal acquisition section 21 corresponds to the period acquisition section.
In this way, the signal acquisition unit 21 acquires the period during which the slider 2 moves in one direction instead of reciprocating as the data acquisition period. Therefore, data collection can be performed in a relatively short time. Here, from the viewpoint of the SN ratio, it is desirable that the data collection period is a period in which the moving speed of the slider 2 is 5 m/min or more.

In addition, in the movement section in which the slider 2 moves during the data collection period, the section in which the slider 2 moves in a loaded state during operation of the equipment provided with the linear guide 10, that is, the movement of the slider 2 during processing of the workpiece W in the processing apparatus It is possible to include a section (processing section) to be processed.
It should be noted that the longer the moving distance of the slider 2 is, the more the amount of data to be collected increases, and the noise component can be reduced by averaging. Therefore, the longer moving distance is desirable. The accuracy of condition monitoring can be improved as the movement distance increases.

In this embodiment, the signal acquisition unit 21 acquires the data collection period based on the trigger signal, but the acquisition method of the data collection period is not limited to the above. For example, the signal acquisition unit 21 may acquire operation cycle information of the linear guide 10 and determine the data collection period based on the acquired information.

The data collection unit 23 collects vibration data detected by the vibration sensor 14 during the data collection period acquired by the signal acquisition unit 21 . That is, the data collection unit 23 collects vibration data in synchronization with the operation cycle (processing cycle) of the linear guide 10 during production.
The storage unit 23 stores the vibration data collected by the data collection unit 23 in a predetermined storage area.

In this embodiment, the condition monitoring device 20A periodically collects vibration data. At this time, the conditions for collecting the vibration data (operation pattern, moving direction of the slider 2, sampling time, data collection time, etc.) are the same each time.
In the linear guide 10, vibration occurs due to the rolling elements 3 rolling on the rolling path, and due to the rolling elements 3 moving in and out of the load area and unload area of the circulation path. In the linear guide 10, the position at which the rolling element shifts from the load area to the no-load area and the position at which the rolling element shifts from the no-load area to the load area are reversed depending on the direction in which the slider 2 moves. In other words, the excitation position is different between the outward trip and the return trip. Therefore, the same vibration data is not measured on the outward trip and the return trip. Therefore, when collecting vibration data periodically, the vibration data are collected under the condition that the movement direction of the slider 2 is always the same.

In consideration of data stability, it is desirable to collect data in a warm-up state. Also, in order to properly grasp the occurrence of anomalies, it is desirable that the data collection interval is at least once a day in the working days.
In FIG. 5, the arrow indicating the moving direction of the slider 2 is directed to the right, but the slider 2 may move in either direction during the data collection period.

The analysis unit 25 analyzes the vibration data stored in the storage unit 24 and monitors the state of the linear guide 10 .
The output unit 26 outputs the state of the linear guide 10 diagnosed by the analysis unit 25 to the display unit 20d shown in FIG. 5 to present the diagnosis result to the user.

The analysis unit 25, for example, calculates a feature value based on the collected vibration data, and compares the calculated feature value with a reference value to diagnose the state of the linear guide 10 (whether or not an abnormality has occurred, etc.). . Here, the feature value can include at least one of an RMS value, an overall value (OA value), a partial overall value (POA value), a crest factor (CF), and a kurtosis. Note that the feature value is not limited to the above, and can be selected as appropriate. Further, if a threshold value of the feature value is set in advance as the reference value, an abnormality can be easily and appropriately detected by comparing the feature value and the threshold value.

When analyzing the vibration data, the analysis unit 25 divides the vibration data into a processing section portion and a portion outside the processing section, and compares the analysis results (for example, the above characteristic values) of each vibration data. good too.
For example, as shown in FIG. 6, the analysis unit 25 may include a comparison diagnosis unit 25a, an abnormal location identification unit 25b, and a determination unit 25c. In this case, the comparison diagnosis unit 25a may compare the analysis results of the divided vibration data, and the determination unit 25c may determine the state of the linear guide 10 based on the comparison result by the comparison diagnosis unit 25a.
By comparing the feature value calculated from the vibration data in the machining zone and the feature value calculated from the vibration data outside the machining zone, it is possible to grasp the deterioration and damage state of the machining zone.
In general, in the linear guide 10, anomalies tend to occur in the machining section where a load is applied. Therefore, if it is predetermined that an abnormality occurs only in the machining interval and does not occur outside the machining interval (that is, the normal value), the feature value of the machining interval and the feature value (normal value) outside the machining interval can be compared. By simply comparing , the state can be easily confirmed even without the time-series data of the feature values. For example, in order to shorten the takt time as much as possible, it is possible to monitor the status of equipment that has extremely few operating patterns suitable for the data collection period. In other words, the comparison diagnosis unit 25a shown in FIG. 6 may compare the feature values in the machining section and outside the machining section.

Furthermore, the analysis unit 25 may divide the vibration data of the entire region into a plurality of sub-section data, and compare the analysis results (for example, feature values) of the divided vibration data. This makes it possible to identify the position where the state changes. For example, if the rolling surface of the guide rail 1 is scratched at one location, the characteristic value changes when the slider 2 passes through that spot.
FIG. 7 shows an example of characteristic values when the rolling surface of the guide rail 1 is damaged at one location. Each point (point) in FIG. 7 is a feature value calculated from the vibration data of each divided sub-section. As described above, when the rolling surface of the guide rail 1 has a scratch at one place, a place (peak) where the characteristic value fluctuates greatly can be confirmed. Therefore, by specifying the location where the characteristic value fluctuates, it is possible to specify the position where the guide rail 1 is damaged (abnormal location).
The abnormal location identification unit 25b shown in FIG. 6 divides the vibration data of the entire region into a plurality of data as described above, and identifies the abnormal location of the linear guide 10 based on the analysis result of the divided data. good too.

It is desirable to consider the difference between the outward and return trips because the locations of the vibrations caused by the collision of the rolling elements are different. Therefore, when collecting data inline, it is desirable to collect only the data of the outward trip if it is an outward trip, and only the data of the return trip if it is a return trip.

Note that the analysis unit 25 arranges in time series the characteristic values calculated from the vibration data divided into the machining zone and the non-machining zone, and monitors the change in tendency to diagnose the state of the linear guide 10. can be In this case, the state of the linear guide 10 can be diagnosed with higher accuracy.
Further, the analysis unit 25 may arrange the feature values calculated without dividing the vibration data into the processing section and the non-processing section in chronological order to monitor the change in tendency. In this case, simple diagnosis cannot be performed by comparing the machining interval and the outside of the machining interval, but the calculation can be simplified and the memory required for analysis can be reduced.

In the present embodiment, the case where the state monitoring device 20A includes the units shown in FIG. 6 has been described, but at least part of the storage unit 24, the analysis unit 25, and the output unit 26, for example, is a device different from the state monitoring device 20A. may be provided. In this case, the state monitoring device 20A transmits the data collected by the data collecting unit 23 to a device different from the state monitoring device 20A, and the device different from the state monitoring device 20A analyzes the data to determine the state of the linear guide 10. can diagnose.

As described above, the condition monitoring device 20A according to the present embodiment allows the slider 2 to move in one direction with respect to the guide rail 1 at a constant speed in the no-load state within the operation cycle or operation pattern of the linear guide 10. is obtained as a data collection period, and vibration data during the data collection period is collected as data for monitoring the state of the linear guide 10 .
In this manner, the condition monitoring device 20A collects vibration data not during machining but during no load. Therefore, it is possible to collect vibration data that minimizes the influence of disturbances that occur during machining. In addition, since data is collected within the operation cycle and operation pattern of the linear guide 10, there is no need to intervene in a diagnostic mode for data collection. Therefore, a decrease in productivity can be prevented. In addition, since the data collection range is the range in which the slider 2 moves in one direction instead of reciprocating, the measurement time can be shortened. Furthermore, since data is collected while the slider 2 is moving at a constant speed, stable data measurement can be performed.

Furthermore, the movement section in which the slider 2 moves during the data collection period can include the section in which the slider 2 of the linear guide 10 moves when processing is performed. As a result, the collected vibration data can include a signal when the vehicle moves through a location where anomalies are likely to occur. Therefore, for example, by comparing the feature value calculated from the vibration data of the machining section and the feature value calculated from the vibration data outside the machining section, it is possible to grasp the deterioration or damage state of the machining section. In this way, anomaly detection can be performed appropriately.

Here, the movement section and movement distance of the slider 2 during the data collection period can be set based on predetermined parameters (processing section, etc.) such as the operation cycle of the linear guide 10 and the type of the linear guide 10 .
For example, as in the technique described in Patent Document 1, when the data collection time is set to be equal to or longer than the passing period of the rolling elements, a system for grasping the passing period of the rolling elements is required. On the other hand, in this embodiment, it is not necessary to separately construct a complicated system for grasping the parameters necessary for setting the data collection period.

In addition, in the present embodiment, by periodically collecting vibration data under the same conditions, the collected vibration data can be arranged in time series and trends can be monitored. Therefore, when the state changes due to the occurrence of an abnormality or the like, it can be appropriately detected. At this time, since the vibration data is collected when the slide 2 moves in the same direction each time, the accuracy of diagnosis can be improved.
For example, when constructing a trigger from an acceleration signal as in the technique described in Patent Literature 2, it is not always possible to collect data under the same conditions each time. In this embodiment, data is collected aiming at a period in which the slide 2 moves in one direction at a constant speed in a predetermined section, so data under the same conditions can be collected each time.

As described above, in the present embodiment, since the measured values during no-load operation during production are used, even for equipment that has a short tact time and operates 24 hours a day, data can be obtained during a series of operation cycles without stopping production. can be collected. As a result, the state of the linear guide 10 can be monitored in-line without affecting production takt time, and planned preventive maintenance can be performed.

(Modification)
In each of the embodiments described above, the case where the vibration sensor 14 is fixed to the table 12 has been described, but the position where the vibration sensor 14 is fixed is not limited to the above. If the vibration sensor 14 can be fixed to the slider 2 of the linear guide 10 depending on the structure of the equipment, the vibration sensor 14 may be directly fixed to the slider 2 . Further, for example, the vibration sensor 14 may be fixed to the end upper surface of the guide rail 1 so as not to interfere with the slider 2 . The vibration detected by the vibration sensor 14 may be axial vibration or vibration in a direction orthogonal to the axial direction, but vibration in a direction orthogonal to the axial direction is preferable.

Further, in each of the above-described embodiments, the case where the vibration of the slider 2 is detected as the physical quantity related to the linear guide 10 has been described, but the physical quantity may be the torque or current of the servomotor 11 . In this case, compared to the case of detecting vibration data, the wiring for installing the sensor for detecting the physical quantity related to the linear guide 10 becomes easier. However, while vibration data directly measures the physical information of the monitored object, torque information and current data contain a lot of information about other elements such as bearings. Diagnostic accuracy tends to be slightly lower.
In addition, the characteristic value is calculated based on the collected vibration data, and the characteristic value is compared with the reference value for judgment. You can compare and judge.

Furthermore, in each of the above embodiments, a processing apparatus such as a machine tool is provided with the linear guide 10. good. Also in this case, data for more accurately diagnosing the state of the linear guide 10 can be appropriately collected as in the above-described embodiment.

It should be noted that the present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device run the program. can also be implemented by reading and executing In this case, the program itself read from the recording medium implements the functions of the embodiment. Also, a recording medium recording the program can constitute the present invention.
Further, by executing a program read by a computer, not only the functions of the embodiments are realized, but also an operating system (OS) running on the computer based on the instructions of the program is one of the actual processes. Some or all of them may be performed, and the functions of the above-described embodiments may be realized by the processing.

DESCRIPTION OF SYMBOLS 1... Guide rail 1a... Raceway surface 2... Slider 2a... Slider main body 2b... End cap 2c... Raceway surface 2d... Return path 2e... Turning path 3... Rolling element 10... Linear guide, DESCRIPTION OF SYMBOLS 11... Servo motor 12... Table 14... Vibration sensor 20... State monitoring device 21... Signal acquisition part 22... Drive control part 23... Data collection part 24... Storage part 25... Analysis part 26... Output part, 30... Tool, W... Work

Claims (10)

A linear guide guide rail state monitoring device for monitoring the state of a linear guide guide rail having a guide rail, a slider, and a plurality of rolling elements,
a drive control unit that controls a drive unit to move the slider at a constant speed relative to the guide rail for one reciprocation or more in a no-load state;
a data collection unit that collects, as data, physical quantities relating to the linear guide while the drive unit is being controlled by the drive control unit;
an analysis unit that analyzes the data collected by the data collection unit and monitors the state of the guide rail of the linear guide;
The analysis unit compares the analysis results of the outward trip data and the return trip data among the data collected by the data collection unit , and if only one of them has a characteristic value peak, the measurement is an error, and if there is a peak of the characteristic value in the data of the forward trip and the data of the return trip, it is judged that there is an abnormality . . 2. The apparatus for monitoring the condition of a guide rail of a linear guide according to claim 1, wherein the comparison diagnosis unit specifies a position where the abnormality occurs in the guide rail by specifying a location where the characteristic value fluctuates. The drive control unit
3. A condition monitoring device for a guide rail of a linear guide according to claim 1 or 2 , wherein the movement section in which the slider is moved includes a section in which the slider moves in a loaded state during operation of the equipment provided with the linear guide. The drive control unit
4. A condition monitoring device for a guide rail of a linear guide according to claim 1 , further comprising a driving condition storage unit for storing driving conditions for controlling said driving unit under the same conditions periodically. The analysis unit is
5. The apparatus according to any one of claims 1 to 4 , further comprising an abnormal location identification unit that divides the data collected by the data collection unit into a plurality of data and identifies the abnormal location of the linear guide based on the analysis result of the divided data. 1. A condition monitoring device for a guide rail of a linear guide according to claim 1. 6. A condition monitoring device for a guide rail of a linear guide according to claim 1, wherein said physical quantity is vibration in a direction orthogonal to a moving direction of said slider. further comprising a vibration sensor that detects the vibration data;
7. The apparatus for monitoring the condition of a guide rail of a linear guide according to claim 6 , wherein the vibration sensor is fixed to the slider or a moving member connected to the slider and movable with respect to the guide rail together with the slider. A servo motor that drives the linear guide,
6. The device for monitoring the condition of a guide rail of a linear guide according to claim 1, wherein said physical quantity is at least one of torque and current of said servomotor. A linear guide guide rail state monitoring method for monitoring the state of a linear guide guide rail having a guide rail, a slider, and a plurality of rolling elements, comprising:
a control step of controlling the drive unit to move the slider at a constant speed with respect to the guide rail for one reciprocation or more in a no-load state;
a collecting step of collecting as data physical quantities relating to the linear guide while the driving unit is being controlled;
an analysis step of analyzing the collected data and monitoring the state of the guide rail of the linear guide;
The analysis step includes:
Among the collected data, comparing the analysis results of the forward pass data and the return pass data , and if there is a peak of the characteristic value only in either one, it is determined that there is a measurement error, A method for monitoring the condition of a guide rail of a linear guide, comprising a comparative diagnosis step of judging that there is an abnormality when there is a peak of characteristic values in the data of the outward trip and the data of the return trip. A program for causing a computer to function as each part of the state monitoring device for the guide rail of the linear guide according to any one of claims 1 to 8 .

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