Motor monitoring device

Abstract

A motor monitoring device according to an aspect of the present disclosure which allows the state of a motor to be easily ascertained comprises: a rotational speed acquisition unit that acquires the rotational speed of the motor that operates according to an operation program; an output value acquisition unit that acquires the output value of the motor; a state information acquisition unit that acquires state information indicating the state of the motor which is different from the rotational speed and the output value; a history information storage unit that associates the rotational speed, the output value, and the state information acquired at predetermined timing and stores the result as history information with an identifier added; and a graph display unit that displays a graph in which a marker indicating a combination of the rotational speed and the output value is plotted with a label indicating the identifier in a graph area with one axis indicating the rotational speed and the other axis indicating the output value.

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 greatly, 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 a motor, various time ratings can be set so that it can operate without overheating under specific conditions. As the time rating, for example, in JIS-C4034-1, there are defined a continuous rating that allows continuous operation, a short-time rating that allows operation for a certain period of time (load time) starting from room temperature, a repetitive rating that allows operation for a certain period of 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 set values 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 technique 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; a state information acquisition unit that acquires state information indicating the state of the motor which is different from the rotation speed and the output value; a history information storage unit that associates the rotation speed, the output value and the state information acquired at predetermined timings and stores them as history information with an identifier added; and a graph display unit that displays a graph plotting markers indicating the combination of the rotation speed and the output value on a graph area where one axis is the rotation speed and the other axis is the output value, with labels indicating the identifier. [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 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, a status information acquisition unit 134, a history information storage unit 135, a graph display unit 136, a history information display unit 137, and a program display unit 138.

[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, torque value, etc. 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. Also, the output value acquisition unit 133 may acquire two or more types of output values.

[0021] The state information acquisition unit 134 acquires state information indicating the state of the spindle motor 20 different from the rotational speed and the output value. In the present embodiment, the state information acquisition unit 134 calculates the estimated time until the spindle motor 20 reaches the overheat temperature when maintaining the rotational speed and the 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 the output value acquired by the output value acquisition unit 133, and uses this estimated time as one of the state information. Also, the state information acquisition unit 134 may use other indicators indicating the state of the spindle motor 20 as alternative or additional state information. For example, the winding temperature of the spindle motor 20 may be used as the state information as it is. Furthermore, the state information may include program position information for specifying the position in the operation program, modal information for designating the operation of the spindle motor 20, etc. Examples of the program position information include the sequence number, line number, block number, etc. Examples of the modal information include commands extracted from the operation program (not limited to those directly designating the operation of the spindle motor 20, including commands that can affect the operation of the spindle motor 20 such as commands for designating tools), set values of the numerical control device 10, etc.

[0022] The history information storage unit 135 associates the rotation speed, output value, and state information acquired at a predetermined timing, and stores them as history information with an identifier added. That is, the history information storage unit 135 regards the rotation speed, output value, and state information of the main shaft motor 20 at the same timing as one record, and adds an identifier with uniqueness to each record for storage. As the identifier, a serial number can be used, or time can be used.

[0023] The timing for acquiring the rotation speed, output value, and state information that the history information storage unit 135 stores as history information may include the timing instructed by the user, when the combination of the rotation speed and output value reaches a predetermined load level, and when an abnormality is detected. By storing the history information at the timing instructed by the user, the user can confirm in detail the state of the main shaft motor 20 at the point of concern. Also, by storing the history information when the combination of the rotation speed and output value reaches a predetermined load level and when the numerical control device 10 detects an abnormality, information that the user desires to confirm can be stored. As the load level for storing the history information, among the areas set to divide the graph area where the combination of the rotation speed and output value can be taken into a plurality of sections, the area that is the maximum load level at which operation is allowed, for example, the area that can be the area between a specific time rating and an instantaneous rating can be set. In FIG. 2, the graph area is divided into four areas: a load area where continuous operation is possible, a load area where intermittent operation is possible, a load area where operation is possible exceptionally for a short time, and an operation area where operation for a short time is not allowed, by the continuous rating, time rating, and maximum output respectively indicated by dotted lines.

[0024] Furthermore, it is preferable that the history information storage unit 135 checks the rotation speed, output value, and status information at regular time intervals and stores multiple combinations of rotation speed, output value, and status information within a preset time range based on a predetermined timing (for example, the time closest to the specified timing and a certain number immediately preceding it) as one or individual history information. In this way, by storing a certain number of consecutive pieces of information at regular intervals, the user can check the rate of change in the operating state, and thus better understand the state of the spindle motor 20.

[0025] The graph display unit 136 displays a graph plotting markers indicating combinations of rotational speed and output values ​​stored in the history information storage unit 135, with labels indicating identifiers attached to a graph area where one axis represents rotational speed and the other axis represents output value. In the example shown in Figure 2, the labels indicating identifiers are attached adjacent to the markers, but the markers may be enlarged and the labels displayed on top of the markers, or they may be displayed separately from the markers using leader lines. By displaying such a graph, the load on the spindle motor 20 can be visualized, and the user can easily identify the corresponding history information, i.e., information other than rotational speed and output values.

[0026] The graph display unit 136 preferably displays the graph in such a way that the user can select the markers to display. Marker selection may also be done indirectly by selecting labels. In Figure 2, the graph display unit 136 has selected a marker labeled with identifier "3", and the display contents of the history information display unit 137 and the program display unit 138 are determined accordingly. By making the display contents of the history information display unit 137 and the program display unit 138 selectable based on the markers displayed by the graph display unit 136, the history information and parts of the operating program that need to be checked can be easily identified. Conversely, the graph display unit 136 may also display markers that correspond to the history information displayed by the history information display unit 137 in an identifiable manner.

[0027] The history information display unit 137 displays at least a portion of the history information corresponding to the marker selected by the user in the graph display unit 136. In Figure 2, the content of the history information with identifier "3" is displayed in the history information display unit 137. The history information display unit 137 may also be provided with buttons to scroll through the history information forward and backward, allowing the user to select the history information. By making the display of the history information display unit 137 correspond to that of the graph display unit 136 in this way, operability can be improved.

[0028] The program display unit 138 displays at least a portion of the operating program. Preferably, the program display unit 138 provides a user interface that allows the user to edit the displayed operating program. That is, it can be configured so that the edited content of the operating program, as determined in the program display unit 138, is reflected in the stored content of the program storage unit 11. Preferably, the program display unit 138 displays in an identifiable manner the portion of the program position information in the history information corresponding to the marker selected by the user in the graph display unit 136 that is identified. In Figure 2, the sequence number "N0007" of the program number "O0001" identified by the history information of the marker identifier "3" selected in the graph display unit 136, and the portion corresponding to the selected marker identifier "3" is displayed identifiable. In this way, by making the display of the program display unit 138 correspond to that of the graph display unit 136, operability can be improved.

[0029] The numerical control device 10 according to this embodiment includes a history information storage unit 135 that associates rotational speed, output value, and status information acquired at predetermined timings and stores them as history information with an identifier added, and a graph display unit 136 that displays a graph plotting markers indicating combinations of rotational speed and output value in a graph area where one axis represents rotational speed and the other axis represents output value, with labels indicating identifiers. As a result, the status of the spindle motor 20, including status information other than rotational speed and output value, can be easily grasped.

[0030] 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.

[0031] 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.

[0032] In the motor monitoring device relating to this disclosure, the history information display unit and the program display unit have arbitrary configurations and do not necessarily have to be selectable by markers on the graph display unit. [Explanation of Symbols]

[0033] 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 Status Information Acquisition Unit 135 History Information Storage Unit 136 Graph display section 137 History Information Display Section 138 Program display section 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 state information acquisition unit that acquires state information indicating the state of the motor, which is different from the rotational speed and the output value, A history information storage unit stores the rotation speed, output value, and status information acquired at predetermined timings, including when the combination of rotation speed and output value reaches a predetermined load level and when an abnormality is detected, as well as program position information that identifies the position within the operation program, as history information with an identifier added. A graph display unit that displays a graph plotting markers indicating the combination of rotational speed and output value in a graph region where one axis represents the rotational speed and the other axis represents the output value, with labels indicating the identifier attached. The graph display unit includes a history information display unit that displays at least a portion of the history information corresponding to the marker selected by the user, The graph display unit includes a program display unit that displays the portion of the history information identified by the program position information corresponding to the marker selected by the user, Equipped with, The motor monitoring device includes a graph display unit that identifiablely displays the marker corresponding to the history information displayed by the history information display unit.

2. The motor monitoring device according to claim 1, wherein the identifier is a time or a serial number.

3. The motor monitoring device according to claim 1 or 2, wherein the predetermined timing includes a timing instructed by the user.

4. The motor monitoring device according to claim 1 or 2, wherein the history information storage unit checks the rotation speed, output value, and status information at regular time intervals and stores a plurality of combinations of the rotation speed, output value, and status information within a preset time range based on the predetermined timing.

5. The motor monitoring device according to claim 1 or 2, wherein the state information includes modal information that specifies the operation of the motor.

6. The motor monitoring device according to claim 1 or 2, wherein the state information acquisition unit calculates, as one of the state information, the estimated time until the motor reaches an overheat temperature while maintaining the rotational speed and output value at that time.

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