WO2024075227A1

WO2024075227A1 - Motor monitoring device

Info

Publication number: WO2024075227A1
Application number: PCT/JP2022/037322
Authority: WO
Inventors: 健二清水; 誠芳賀
Original assignee: ファナック株式会社
Priority date: 2022-10-05
Filing date: 2022-10-05
Publication date: 2024-04-11
Also published as: JPWO2024075227A1; JP7227436B1

Abstract

A motor monitoring device according to one aspect of the present disclosure comprises: a rotational speed acquisition unit that acquires the rotational speeds of a plurality of motors; an output value acquisition unit that acquires output values of the plurality of motors; a deviation calculation unit that calculates the deviation in the rotational speed and output value among the motors; and a graph display unit that plots a plurality of markers indicating the combination of the rotational speed and the output value for each of the motors in a graph area of which one axis is the rotational speed and the other axis is the output value. The graph display unit includes: a graph area setting unit that, with regard to expected combinations of the rotational speed and the output value, divides the graph area into a plurality of load zones with different load levels on the basis of a plurality of time ratings of the motors, and displays the plurality of load zones in an identifiable manner; a plotting unit that plots the plurality of markers in the graph area; and a connecting line drawing unit that draws connecting lines connecting the markers that correspond with each other in a manner that differs according to the deviation.

Description

Motor Monitoring Device

The present invention relates to a motor monitoring device.

For example, in motors where the load can change greatly, such as the spindle motor of a machine tool, if the load continues to be high, heat can accumulate and the motor can overheat. Various time ratings can be set for such motors so that they can operate without overheating under specific conditions. Time ratings, for example, JIS-C4034-1 specifies continuous ratings that allow continuous operation, short-term ratings that allow operation for a certain time (load time) from room temperature, and repetitive ratings that allow operation for a certain time (load time rate) within a specified cycle time.

For example, in machine tools, it is envisioned that the actual operating state of the motor needs to be grasped and settings such as the motor speed can be adjusted to reduce the margin for overheating and perform more efficient machining. As a means for grasping the current operating state of the motor, a load meter is known which plots the current values of the motor's rotation speed and output on a graph that displays lines indicating the various ratings mentioned above, with one axis representing the rotation speed and the other axis representing the output (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 10-90011

For example, there are devices, such as multi-spindle machine tools, that drive multiple motors under the same conditions. In such devices, if the status of the multiple motors cannot be grasped, it may not be possible to adjust the settings appropriately.

A motor monitoring device according to one aspect of the present disclosure includes a rotation speed acquisition unit that acquires rotation speeds of multiple motors, an output value acquisition unit that acquires output values of the multiple motors, a deviation amount calculation unit that calculates deviation amounts between the rotation speeds and the output values of the motors, and a graph display unit that plots multiple markers indicating combinations of the rotation speeds and the output values for each of the motors in a graph area with one axis representing the rotation speeds and the other axis representing the output values. The graph display unit has a graph area setting unit that divides the graph area into multiple load zones with different load levels based on multiple time ratings of the motors for expected combinations of the rotation speeds and the output values, and displays the multiple load zones in an identifiable manner, a plot unit that plots the multiple markers in the graph area, and a connection line drawing unit that draws connection lines connecting the corresponding markers in different ways depending on the deviation amount.

This disclosure makes it easy to understand the status of multiple motors.

1 is a block diagram showing a configuration of a machine tool equipped with a motor monitoring device according to a first embodiment of the present disclosure. FIG. FIG. 2 is a diagram illustrating an example of a display by the motor monitoring device of FIG. 1.

Embodiments of the present disclosure will now be described with reference to the drawings. Figure 1 is a block diagram showing the configuration of a machine tool 1 equipped with a motor monitoring device according to a first embodiment of the present disclosure.

The machine tool 1 includes a numerical control device 10, which is one embodiment of the motor monitoring device according to the present invention, a plurality of spindle motors 20, a plurality of rotation speed detectors 21 that detect the rotation speed of the spindle motors 20, a plurality of current detectors 22 that detect the current of the spindle motors 20, a display device 30 that displays a screen in accordance with the numerical control device 10, and an input device 40 that the user uses to input data to the numerical control device 10.

The numerical control device 10 has a memory, a processor (CPU), an input/output interface, etc., and can be realized by one or more computer devices that execute appropriate control programs. The components of the numerical control device 10 described below are classifications of the functions (operations of the processor) of the numerical control device 10, and do not necessarily have to be clearly distinguished in terms of physical configuration and program configuration.

The spindle motor 20 is typically a motor that rotates a cutting tool or a workpiece, and the load can vary regardless of the rotation speed depending on the machining conditions. The rotation speed detector 21 and the current detector 22 can each be configured with a well-known sensor.

The display device 30 is a well-known display that displays according to signals input from the numerical control device 10. The display device 30 may be configured integrally with the numerical control device 10. The input device 40 is a device that allows the user to input information to the numerical control device 10, and may have a well-known configuration such as a keyboard or mouse. The input device 40 may also be configured integrally with the numerical control device 10. The input device 40 may also be configured integrally with the display device 30. Specifically, the display device 30 and the input device 40 may be a single input/output device such as a touch panel.

In this embodiment, the numerical control device 10 includes a program memory unit 11, a motor control unit 12 that controls the operation of the motor that drives the drive shaft of the machine tool 1, including the spindle motor 20, and a motor monitoring unit 13 that executes the functions of the motor monitoring device according to the present disclosure.

The program memory unit 11 stores the machining program to be executed by the machine tool 1. The machining program includes a number of blocks that each specify a unit operation of the machine tool 1. Each block includes one or more words that each consist of a combination of a number of characters. Generally, each block is first assigned a sequence number to identify the block.

The motor control unit 12 executes the machining procedure described in the machining program by controlling the spindle motor 20 and the motors of the other drive axes of the machine tool 1 according to the machining program. The configuration of the motor control unit 12 is similar to that of a well-known numerical control device, so a detailed description will be omitted.

The motor monitoring unit 13 includes a rotation speed acquisition unit 131, an output value acquisition unit 132, a deviation amount calculation unit 133, a graph display unit 134, a notification unit 135, a stop command unit 136, and an override command unit 137.

The rotation speed acquisition unit 131 acquires the rotation speed of the spindle motor 20 from the rotation speed detector 21. The rotation speed acquisition unit 131 may acquire the rotation speed of the spindle motor 20 via the motor control unit 12.

The output value acquisition unit 132 acquires output values of the spindle motor 20, such as a current value, a power value, and a torque value. In this embodiment, the output value acquisition unit 132 acquires the current value of the spindle motor 20 from the current detector 22, and is intended to use the power value and torque value calculated from the current value as the output value, but the output value acquisition unit 132 may be configured to use the detected value of the current value, etc. as the output value directly. The output value acquisition unit 132 may acquire an output value or a value required to calculate an output value from the motor control unit 12. In addition, the type of output value acquired by the output value acquisition unit 132 may be one type, or three or more types.

The deviation calculation unit 133 calculates the deviation between the rotation speed and the output value of the spindle motor 20. The deviation may be calculated as the deviation for each of the rotation speed and the output value independently, or may be calculated as the deviation of the values obtained as a function of the rotation speed and the output value.

The graph display unit 134 plots a number of markers indicating combinations of rotation speed and output value for each spindle motor 20 in a graph area with one axis representing the rotation speed and the other axis representing the output value. The graph display unit 134 has a graph area setting unit 1341, a plotting unit 1342, a connection line drawing unit 1343, a reference setting unit 1344, and a reference selection unit 1345.

The graph area setting unit 1341 displays a graph area on the display device 30, with one axis representing the rotation speed and the other axis representing the output value. The graph area setting unit 1341 divides the graph area into a number of load zones and displays the multiple load zones in an identifiable manner. More specifically, the graph area setting unit 1341 divides the graph area into a number of load zones with different load levels based on a number of time ratings of the spindle motor 20 for expected combinations of rotation speed and output value. This allows the user to easily grasp the safety or risk of the operating state of the spindle motor 20.

The graph area setting unit 1341 preferably uses colors or patterns to display multiple load zones in an identifiable manner. By using colors or patterns, it is easy to understand which load zone a combination of rotation speed and output value belongs to. In addition, by using colors or patterns that make it easy to intuitively understand the level of the load level in that load zone, such as blue, yellow, or red, the degree of danger of the operating state of the spindle motor 20 can be easily understood.

If the combination of the rotation speed and output value of the spindle motor 20 is equal to or lower than the continuous rating, the load on the spindle motor 20 can continue to operate indefinitely. For this reason, it is preferable that the upper limit of the load zone with the lowest load level be a curve that represents the continuous rating.

The graph area setting unit 1341 preferably sets the boundary of one of the multiple load zones, preferably the lower limit of the load zone with the highest load level, as a line connecting the maximum values of multiple time ratings (e.g. short-term ratings and repetitive ratings with different load time rates) at the same rotation speed. A combination of rotation speed and output value plotted in an area beyond this boundary line indicates a dangerous output state that could immediately cause a malfunction. Conversely, if the boundary line is not exceeded, there is a possibility that no problem will occur for a short period of time.

The graph area setting unit 1341 may be configured to select at least one of the boundaries of a plurality of load zones according to user input. Specifically, the graph area setting unit 1341 may be configured to select the boundaries of the load zone from among the above-mentioned continuous rating, the maximum value of a plurality of time ratings, a plurality of short-term ratings with different load times, and a plurality of repetitive ratings with different load time rates. This allows a load zone that is deemed appropriate to be set in consideration of the content of the machining performed by the machine tool 1, thereby making it possible to more appropriately grasp the risk of the spindle motor 20.

The plot unit 1342 plots multiple markers in one-to-one correspondence with the spindle motors 20 in the graph area. It is preferable that the plot unit 1342 plots the markers in a different manner for each corresponding spindle motor 20. For example, the plot unit 1342 can plot the markers in a manner that allows the corresponding spindle motor 20 to be identified based on differences in the marker's shape, color, pattern, etc. In the example shown in FIG. 2, the shape of the marker identifies which of the three spindle motors 20 it is.

The plot unit 1342 may also change the state of the marker in accordance with state values of each spindle motor 20, such as the load level, temperature, and estimated time until the overheat temperature is reached. In the example shown in FIG. 2, the load level of the corresponding spindle motor 20 is indicated by the pattern (hatching) of the marker. In this way, the plot unit 1342 indicates state values by the state of the marker, allowing the user to grasp the operating state of the spindle motor 20 from multiple perspectives.

The connection line drawing unit 1343 draws connection lines in the plot area that connect corresponding markers in different modes depending on the deviation amount. Specifically, the connection line drawing unit 1343 may draw connection lines in different modes depending on whether the deviation amount exceeds a predetermined deviation tolerance, or may draw connection lines in different modes depending on the ratio between the deviation amount and the predetermined deviation tolerance. As the mode of the connection line that changes depending on the deviation amount, for example, it is possible to use color, thickness, pattern, etc. to allow the user to grasp the magnitude of the deviation amount. This allows the user to easily grasp motors whose load state is significantly different from other motors 20.

The connection line drawing unit 1343 preferably draws connection lines between the marker of one reference spindle motor 20 and the other markers. In particular, when displaying three or more markers, by determining the reference spindle motor 20, it is possible to avoid display complexity and to grasp the status of all spindle motors 20 relatively easily.

The reference setting unit 1344 sets a reference spindle motor 20 so as to maximize the number of other spindle motors 20 whose deviation amount is within a predetermined range. By setting a reference spindle motor 20 in this manner, spindle motors 20 that are significantly different from the others in at least one of the rotation speed and output value can be clearly displayed, so that the user can easily identify spindle motors 20 that are abnormal.

The reference selection unit 1345 provides an interface that allows the user to select a reference spindle motor 20. By selecting the reference spindle motor 20 at the user's discretion, it becomes possible to set an appropriate reference. For example, by using a spindle motor 20 that has been replaced with a new one as the reference, the degree of deterioration of the other spindle motors 20 can be grasped relatively appropriately. Furthermore, when there are multiple spindle motors 20 with the largest number of other spindle motors 20 whose deviation amounts are within a predetermined range in the reference setting unit 1344, the reference selection unit 1345 may be used to allow the user to select a reference motor from among the multiple spindle motors 20 with the largest number of other spindle motors 20 whose deviation amounts are within a predetermined range.

If the deviation exceeds a predetermined deviation amount for notification, the notification unit 135 issues a notification to that effect. This makes it possible to notify the user that there may be an abnormality in the operating state of any of the spindle motors 20. The notification can typically be made by displaying a warning message on the display device 30, sounding an alarm, turning on a warning light, etc.

The stop command unit 136 stops the spindle motors 20 when the deviation exceeds a predetermined stop deviation. This makes it possible to prevent the occurrence of defective products caused by an abnormality in one of the spindle motors 20, the spread of the abnormality to other components, etc.

The override command unit 137 changes the rotation speed of the spindle motor 20 when the deviation amount exceeds the override deviation amount. Specifically, the override command unit 137 inputs an override command to the motor control unit 12 when the deviation amount exceeds a predetermined override deviation amount. The override command is a command to change the speed of the spindle motor 20 to a speed different from the speed specified by the machining program, for example, to a speed at a certain ratio to the speed specified by the machining program.

As described above, the numerical control device 10 according to this embodiment displays connection lines in a manner that allows the amount of deviation to be determined, allowing the user to grasp the status of all spindle motors 20 relatively easily.

The following supplementary notes are further disclosed regarding the above-described embodiment and modified examples.
(Appendix 1)
The motor monitoring device (10) comprises a rotation speed acquisition unit (131) that acquires the rotation speeds of multiple motors (20), an output value acquisition unit (132) that acquires output values of the multiple motors (20), a deviation amount calculation unit (133) that calculates a deviation amount of the rotation speed and output value between the motors (20), and a graph display unit (134) that plots multiple markers indicating combinations of rotation speed and output value for each motor (20) in a graph area having one axis representing the rotation speed and the other axis representing the output value, and the graph display unit (134) has a graph area setting unit (1341) that divides the graph area into multiple load zones with different load levels based on multiple time ratings of the motors (20) for expected combinations of rotation speed and output value, and displays the multiple load zones in an identifiable manner, a plot unit (1342) that plots the multiple markers in the graph area, and a connection line drawing unit (1343) that draws connection lines connecting corresponding markers in different manners depending on the deviation amount.

(Appendix 2)
The plotting section (1342) may plot the markers in different manners for each corresponding motor (20).

(Appendix 3)
3. The motor monitoring device according to claim 1, wherein the connection line drawing unit draws the connection line in a different manner depending on whether the deviation amount exceeds a predetermined deviation allowance or not.

(Appendix 4)
The motor monitoring device according to claim 1 or 2, wherein the connection line drawing unit (1343) draws the connection line in a different manner depending on a ratio between the deviation amount and a predetermined deviation allowance amount.

(Appendix 5)
The motor monitoring device (10) may further include a notification unit (135) that issues a notification when the deviation amount exceeds a predetermined notification deviation amount.

(Appendix 6)
The motor monitoring device (10) may further include a stop command unit (136) that stops the motor (20) when the deviation amount exceeds a predetermined stop deviation amount.

(Appendix 7)
The motor monitoring device (10) may further include an override command unit (137) that changes the rotation speed of the motor (20) when the deviation amount exceeds a predetermined override deviation amount.

(Appendix 8)
The connection line drawing unit (1343) may draw connection lines between the marker of one reference motor (20) and other markers.

(Appendix 9)
The graph display section (134) may further include a reference setting section (1344) for setting a reference motor (20) so as to maximize the number of other motors (20) whose deviation amounts are within a predetermined range.

(Appendix 10)
The graph display section (134) may further include a reference selection section (1345) that allows the user to select a reference motor (20).

　Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the contents described in the claims and their equivalents.

The motor monitoring device according to the present disclosure may be provided independently of the numerical control device that controls the machine tool, and may be used to check the state of motors other than the spindle motor of the machine tool. For example, the motor monitoring device according to the present disclosure may be a management computer that manages one or more numerical control devices to which the functionality of the motor monitoring unit of the above-described embodiment has been added.

In the motor monitoring device according to the present disclosure, the notification unit, the stop command unit, and the override command unit may be omitted. In addition, the graph display unit of the motor monitoring device according to the present disclosure may not have a standard setting unit and a standard selection unit.

1 Machine tool 10 Numerical control device (motor monitoring device)
REFERENCE SIGNS LIST 11 program storage unit 12 motor control unit 13 motor monitoring unit 131 rotation speed acquisition unit 132 output value acquisition unit 133 deviation amount calculation unit 134 graph display unit 1341 graph area setting unit 1342 plot unit 1343 connection line drawing unit 1344 reference setting unit 1345 reference selection unit 135 notification unit 136 stop command unit 137 override command unit 20 spindle motor 21 rotation speed detector 22 current detector 30 display device 40 input device

Claims

A rotation speed acquisition unit that acquires rotation speeds of a plurality of motors;
an output value acquisition unit that acquires output values of the plurality of motors;
a deviation amount calculation unit that calculates a deviation amount of the rotation speed and the output value between the motors;
a graph display unit that plots a plurality of markers indicating combinations of the rotation speed and the output value for each of the motors in a graph area having the rotation speed on one axis and the output value on the other axis;
Equipped with
The graph display unit includes:
a graph area setting unit that divides the graph area into a plurality of load zones having different load levels based on a plurality of time ratings of the motor for each possible combination of the rotation speed and the output value, and that displays the plurality of load zones in a distinguishable manner;
a plotting unit for plotting the plurality of markers in the graph area;
a connection line drawing unit that draws a connection line connecting the corresponding markers in a different manner according to the amount of deviation;
A motor monitoring device comprising:
The motor monitoring device according to claim 1, wherein the plotting unit plots the markers in different ways for each corresponding motor.
The motor monitoring device according to claim 1 or 2, wherein the connection line drawing unit draws the connection line in a different manner depending on whether the deviation amount exceeds a predetermined deviation tolerance.
The motor monitoring device according to claim 1 or 2, wherein the connection line drawing unit draws the connection line in a different manner depending on the ratio between the deviation amount and a predetermined deviation tolerance amount.
The motor monitoring device according to any one of claims 1 to 4, further comprising a notification unit that issues a notification when the deviation amount exceeds a predetermined notification deviation amount.
The motor monitoring device according to any one of claims 1 to 5, further comprising a stop command unit that stops the motor when the deviation amount exceeds a predetermined stop deviation amount.
The motor monitoring device according to any one of claims 1 to 6, further comprising an override command unit that changes the rotation speed of the motor when the deviation amount exceeds a predetermined override deviation amount.
The motor monitoring device according to any one of claims 1 to 7, wherein the connection line drawing unit draws the connection lines between the marker of one of the motors that serves as a reference and the other markers.
The motor monitoring device according to claim 8, wherein the graph display unit further includes a reference setting unit that sets the reference motor so that the number of other motors whose deviation amount is within a predetermined range is maximized.
The motor monitoring device according to claim 8 or 9, wherein the graph display unit further includes a reference selection unit that allows a user to select the motor that will be the reference.