Motor monitoring device

Abstract

According to one embodiment of the present disclosure, a motor monitoring device that can easily ascertain the state of a motor comprises a rotational speed acquisition unit that acquires the rotational speed of a motor that operates in accordance with an operation program, an output value acquisition unit that acquires an output value for the motor, and a graph display unit that plots a marker that represents a combination of the rotational speed and the output value at a graph area where one axis is the rotational speed and the other axis is the output value. The graph display unit has a unit area setting unit that sets a plurality of unit areas that divide the graph area into a grid and a format modification unit that modifies the display format of the marker by unit area in accordance with a prescribed indicator.

Description

Technical Field

[0001] The present invention relates to a motor monitoring device.

Background Art

[0002] For example, in a motor where the load can change significantly, such as the spindle motor of a machine tool, if the high-load state continues, heat may accumulate and there is a risk of overheating. For such motors, various time ratings can be set to operate without overheating under specific conditions. As the time ratings, for example, in JIS-C4034-1, there are defined a continuous rating that can be continuously operated, a short-time rating that can be operated for a certain time (load time) from the state of room temperature, a repetitive rating that can be operated for a certain time (load time ratio) within a predetermined cycle time, and the like.

[0003] It has also been proposed to estimate the time until the motor overheats when maintaining the current operating state (see, for example, Patent Document 1). If the time until overheating is known, it is possible to determine whether the current processing can be continued until the end.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Merely estimating the time until overheating cannot easily grasp the safety and remaining capacity of the motor operation. Specifically, for example, when adjusting the set value such as the motor speed so that the margin against overheating is minimized and the most efficient processing can be performed, it is not easy to determine how much the set value should be increased or decreased. Therefore, a technology that can easily grasp the state of the motor is desired.

Means for Solving the Problems

[0006] A motor monitoring device according to one aspect of the present disclosure includes: a rotation speed acquisition unit that acquires the rotation speed of a motor operating in accordance with an operating program; an output value acquisition unit that acquires the output value of the motor; and a graph display unit that plots a marker indicating a combination of the rotation speed and the output value on a graph region where one axis represents the rotation speed and the other axis represents the output value, wherein the graph display unit includes a unit region setting unit that sets a plurality of unit regions by dividing the graph region into a grid, and a mode changing unit that changes the display mode of the marker for each unit region according to a predetermined index. [Effects of the Invention]

[0007] According to this disclosure, the motor's status can be easily determined. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing the configuration of a machine tool equipped with a motor monitoring device according to the first embodiment of this disclosure. [Figure 2] This table shows examples of the information stored by the information storage unit of the motor monitoring device shown in Figure 1. [Figure 3] This figure illustrates the display shown by the motor monitoring device in Figure 1. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present disclosure will 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 the first embodiment of the present disclosure.

[0010] The machine tool 1 comprises a numerical control device 10 which is one embodiment of the motor monitoring device according to the present invention, a spindle motor 20, a rotation speed detector 21 which detects the rotation speed of the spindle motor 20, a current detector 22 which detects the current of the spindle motor 20, a temperature detector 23 which detects the winding temperature of the spindle motor 20, a display device 30 which displays information on the screen according to the numerical control device 10, and an input device 40 which is used by the user to input information to the numerical control device 10.

[0011] The numerical control device 10 controls the operation of the spindle motor 20 and other components according to an operation program (called a machining program in the numerical control device) so that a predetermined machining operation can be performed on the workpiece in the machine tool 1. The numerical control device 10 can be implemented by one or more computer devices that have memory, a processor (CPU), input / output interfaces, etc., and execute an appropriate control program. The components of the numerical control device 10 described below are classifications of the functions of the numerical control device 10 and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0012] The spindle motor 20 is typically a motor that rotates a cutting tool or workpiece. The spindle motor 20 operates according to the operating program as described above, but the load may fluctuate independently of the rotational speed depending on the machining conditions. The rotational speed detector 21, current detector 22, and temperature detector 23 can each be composed of well-known sensors.

[0013] The display device 30 is a well-known display that displays information 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 for the user to input information to the numerical control device 10, and may be 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. Furthermore, the input device 40 may 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.

[0014] In this embodiment, the numerical control device 10 includes a program storage unit 11, a motor control unit 12 that controls the operation of a motor that drives the drive shaft of a machine tool 1 including a spindle motor 20, and a motor monitoring unit 13 that performs the functions of the motor monitoring device according to this disclosure.

[0015] The program storage unit 11 stores the operation program to be executed in the machine tool 1. The operation program contains multiple blocks, each specifying a unit operation of the machine tool 1. Each block contains one or more words consisting of combinations of multiple characters. Generally, each block is initially assigned a sequence number to identify that block.

[0016] The motor control unit 12 executes the machining procedure described in the operation program by controlling the spindle motor 20 and the motors of the other drive axes of the machine tool 1 according to the operation program. The configuration of the motor control unit 12 is similar to that of well-known numerical control devices, so a detailed explanation is omitted.

[0017] The motor monitoring unit 13 includes a program acquisition unit 131, a rotation speed acquisition unit 132, an output value acquisition unit 133, an estimated time calculation unit 134, an information storage unit 135, and a graph display unit 136.

[0018] The program acquisition unit 131 acquires an operation program from the program storage unit 11 that specifies the operation to be monitored for the spindle motor 20. In other words, the program acquisition unit 131 loads the target operation program into the working memory.

[0019] The rotation speed acquisition unit 132 acquires the rotation speed of the spindle motor 20 from the rotation speed detector 21. The rotation speed acquisition unit 132 may also acquire the rotation speed of the spindle motor 20 via the motor control unit 12.

[0020] The output value acquisition unit 133 acquires output values such as, for example, the current value, power value, and torque value of the spindle motor 20. In the present embodiment, the output value acquisition unit 133 is intended to acquire the current value of the spindle motor 20 from the current detector 22 and use the power value calculated from the current value as the output value. However, the output value acquisition unit 133 may be configured to use the detected value such as the current value as the output value as it is. The output value acquisition unit 133 may acquire the output value or the value necessary for calculating the output value from the motor control unit 12. Further, the output value acquisition unit 133 may acquire two or more types of output values.

[0021] The estimated time calculation unit 134 calculates the estimated time until the spindle motor 20 reaches the overheat temperature when maintaining the rotational speed and output value at that time based on the winding temperature of the spindle motor 20 acquired from the temperature detector 23 and the current value or output value acquired by the output value acquisition unit 133.

[0022] The information storage unit 135 stores operation information regarding the operation state of the spindle motor 20 at regular time intervals. The operation information includes the rotational speed and output value, and may include the position information of the corresponding instruction of the operation program, modal information specifying the operation of the spindle motor 20, and the like. Examples of the position information of the operation program include the sequence number, line number, block number, and the like. Examples of the modal information include instructions extracted from the operation program (not limited to those directly specifying the operation of the spindle motor 20, and including instructions that can affect the operation of the spindle motor 20 such as instructions specifying tools), setting values such as the upper limit value of the acceleration of the numerical control device 10, and the like. Further, the information storage unit 135 may calculate in advance values such as the load level used in the graph display unit 136 as described later and store them as one element of the operation information.

[0023] The time interval for storing operation information may be a fixed time determined in advance, or may be the time obtained by dividing the processing time estimated from the operation program by the preset number of scheduled operation information acquisitions. Further, the information storage unit 135 may be configured to store operation information at a time interval specified by the user via the input device 40 or the like. FIG. 2 illustrates the content of the operation information stored by the information storage unit 135. As is clear from the figure, the information storage unit 135 may be configured to create a relational database with the acquisition time of the data or the serial number as the unique key for the operation information. Note that "-" in the figure means that it cannot be calculated or the corresponding information does not exist.

[0024] As illustrated in FIG. 3, the graph display unit 136 displays a graph that plots markers indicating combinations of rotation speed and output values in a graph area where one axis represents the rotation speed and the other axis represents the output value. It includes a unit area setting unit 1361, a load area setting unit 1362, a mode change unit 1363, a margin setting unit 1364, and a proposal display unit 1365.

[0025] The unit area setting unit 1361 sets a plurality of unit areas obtained by dividing the graph area into a grid pattern. In FIG. 3, the boundaries of the unit areas are indicated by broken lines. These unit area boundary lines are for explaining the unit areas and may not actually exist on the screen displayed on the display device 30. The unit area setting unit 1361 may determine the size of the unit areas based on user input. Thereby, while ensuring the amount of information necessary for the mode change unit 1363 to change the display mode of the markers, a sufficient number of unit areas can be set. The unit area setting unit 1361 may be configured such that the user can specify the length of the unit areas on each axis, or may be configured such that the user can specify the number (number of divisions) of the unit areas on each axis.

[0026] The load area setting unit 1362 divides the graph area into multiple load areas with different load levels. The load areas can be set using combinations of rotational speed and output values ​​where the load on the main shaft motor 20 is considered to be equal, for example, various ratings as boundaries. In Figure 3, the graph area is divided into four areas by continuous rating, time rating, and maximum output, respectively, indicated by dashed lines: a continuous load area where continuous operation is possible, a short-time load area where intermittent operation is possible, a maximum load area where operation is exceptionally possible only temporarily, and an inoperable area where even short-term operation is not permitted. Note that the boundaries of these load areas do not necessarily have to be present on the screen displayed on the display device 30.

[0027] The mode changing unit 1363 changes the display mode of the marker for each unit area according to a predetermined index. This allows for the display of additional information on the two-dimensional graph, making the status of the spindle motor 20 easily understandable to the user. Examples of changes to the marker mode by the mode changing unit 1363 include changing the color according to the index value (e.g., blue, yellow, red), changing the density or brightness according to the index value, and changing the length or size of the marker according to the index value. In other words, it is preferable that the mode changing unit 1363 changes the display mode of the marker based on a predetermined rule so that the magnitude of the index value can be identified.

[0028] Indicators for determining the marker's configuration include the frequency of occurrence of combinations of rotational speed and output value in each unit area, for example, the load level determined by the area set by the load area setting unit 1362, and the estimated time until the overheat temperature calculated by the estimated time calculation unit 134 is reached. The configuration change unit 1363 may change multiple configurations of the marker according to different indicators.

[0029] When changing the marker's appearance according to the frequency of occurrence of combinations of rotational speed and output value for each unit area, the appearance changing unit 1363 may change the marker's display appearance according to the ratio of the number of operating information belonging to a unit area to the total number of operating information or the number of operating information with an output value (excluding those with an output value of zero) within a predetermined time range. In this way, by using a relative value rather than an absolute number of frequencies, the marker's appearance can be changed significantly, allowing the user to grasp the state of the spindle motor 20 relatively easily. The time range for counting the frequency of occurrence may be set based on the completion of acceleration or deceleration of the spindle motor 20, or it may be the entire range from the start to the end of operation of the spindle motor 20.

[0030] The margin setting unit 1364 sets the margin amount, which is the allowable range of distance from the boundary of the load area for each combination of rotational speed and output value. In Figure 3, the boundary of the allowable range is shown by a dashed line. In the illustrated example, the boundary is rectangular because the allowable range is set for each axis, but the allowable range may also be set as a two-dimensional distance considering both axes so that the boundary is circular. Note that this boundary of the allowable range does not necessarily have to exist on the screen displayed on the display device 30.

[0031] The suggestion display unit 1365 adds a suggestion display to the marker that proposes changes to the operating conditions of the spindle motor 20 based on the load level. In Figure 3, a downward-left arrow suggesting a reduction in load is added as a suggestion display to markers with load levels exceeding the time rating, and an upward-right arrow suggesting an increase in load is added as a suggestion display to markers with load levels below the time rating. Note that the output value of the spindle motor 20 is not set by itself, but mainly increases in conjunction with an increase in the rotational speed of the spindle motor 20, so as a result the combination of rotational speed and output value moves in the direction of the arrow in the suggestion display. The suggestion display unit 1365 may be configured to display the suggestion display in a way that the user can select, and to launch an editor that displays the corresponding part of the operating program in an editable manner when a suggestion display is selected.

[0032] The suggestion display unit 1365 may be configured to add a suggestion display when the distance of the rotational speed and output value combination from the load area boundary is greater than or equal to the margin amount. If an increase in output is suggested when the rotational speed and output value combination is close to the load area boundary, there is a risk that the changed rotational speed and output value combination will exceed the load area boundary. For this reason, it is preferable to suggest a change in the operating conditions of the spindle motor 20 only when there is sufficient distance to the load area boundary. When suggesting a decrease in output, there is no need to consider the margin amount from a safety standpoint, but a decrease in output may result in the disadvantage of increased processing time. For this reason, it is preferable not to actively suggest a decrease in output when the distance is close to the load area boundary.

[0033] The numerical control device 10 according to this embodiment includes a graph display unit 136 which has a unit area setting unit 1361 that sets a plurality of unit areas by dividing the graph area into a grid, and a mode changing unit 1363 that changes the display mode of the marker for each unit area according to a predetermined index, so that the user can grasp the status of the spindle motor 20 from more perspectives.

[0034] Although embodiments of the present disclosure have been described above, the present invention is not limited to the embodiments described above. Furthermore, the effects described in the embodiments described above are merely a list of preferred effects arising from the present invention, and the effects of the present invention are not limited to those described in the embodiments described above.

[0035] The motor monitoring device according to this disclosure may be provided independently of the numerical control device that controls the machine tool, and may be used to check the status of motors other than the spindle motor of the machine tool, such as the motor of a kneader. For example, the motor monitoring device according to this disclosure may be a management computer that manages one or more numerical control devices, such as a control device for a kneader, or a management computer that manages such a control device, with the functions of the motor monitoring unit of the above embodiment added. Furthermore, in the motor monitoring device according to this disclosure, the load area setting unit, margin setting unit, and suggestion display unit can be configured arbitrarily. [Explanation of symbols]

[0036] 1 Machine tools 10. Numerical control device (motor monitoring device) 11 Program Storage Unit 12 Motor control unit 13 Motor Monitoring Unit 131 Program Acquisition Section 132 Rotation speed acquisition unit 133 Output Value Acquisition Unit 134 Estimated Time Calculation Unit 135 Information Storage Department 136 Graph display section 1361 Unit area setting unit 1362 Load area setting section 1363 Change of form section 1364 Margin Setting Section 1365 Suggestion display area 20 Main shaft motor 21. Rotation speed detector 22 Current detector 23 Temperature detector 30 Display device 40 Input devices

Claims

1. A rotation speed acquisition unit that acquires the rotation speed of a motor operating according to an operating program, An output value acquisition unit that acquires the output value of the motor, A graph display unit plots markers indicating the combination of rotational speed and output value on a graph region where one axis represents the rotational speed and the other axis represents the output value. Equipped with, The aforementioned graph display unit is A unit area setting unit sets multiple unit areas by dividing the graph area into a grid, A mode changing unit that changes the display mode of the marker for each unit area according to a predetermined indicator, A load area setting unit divides the graph area into multiple load areas with different load levels, A suggestion display unit adds a suggestion display to the marker that suggests a change in the operating conditions of the motor based on the load level, It has, The motor monitoring device includes a suggestion display unit that adds a display suggesting to reduce the load to markers with load levels exceeding a predetermined boundary, and a display suggesting to increase the load to markers with load levels below the predetermined boundary.

2. The system further includes an information storage unit that stores the rotation speed and the output value at regular time intervals. The motor monitoring device according to claim 1, wherein the mode changing unit changes the display mode of the marker according to the frequency of occurrence of the combination of rotation speed and output value for each unit region.

3. The motor monitoring device according to claim 2, wherein the mode changing unit changes the display mode of the marker according to the frequency of occurrence of combinations of rotational speed and output value within a predetermined time range based on the completion of acceleration or deceleration of the motor.

4. The motor monitoring device according to claim 2, wherein the mode changing unit changes the display mode of the marker according to the frequency of occurrence of the combination of rotational speed and output value over the entire range from the start to the end of operation of the motor.

5. The motor monitoring device according to any one of claims 1 to 4, wherein the mode changing unit changes the display mode of the marker so that the load level of the unit area can be identified.

6. The motor monitoring device according to any one of claims 1 to 4, wherein the unit area setting unit determines the size of the unit area based on user input.

7. The graph display unit further includes a margin setting unit that sets a margin amount which is the allowable range of the distance from the boundary of the load area for the rotational speed and the output value. The motor monitoring device according to any one of claims 1 to 4, wherein the suggested display unit adds the suggested display when the distance from the boundary of the load area for the combination of rotational speed and output value is greater than or equal to the margin amount.

8. The motor further comprises an estimated time calculation unit that calculates the estimated time until it reaches an overheat temperature while maintaining the aforementioned rotational speed and output value at that time. The motor monitoring device according to any one of claims 1 to 4, wherein the mode changing unit changes the display mode of the marker according to the estimated time.

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