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

Motor Monitoring Device

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

[0002] For example, in motors where the load can vary greatly, such as the spindle motor of a machine tool, if the load continues to be high, heat may accumulate and the motor may overheat. Various time ratings may be set for such motors so that they can operate without overheating under specific conditions. JIS-C4034-1, for example, specifies time ratings such as a continuous rating that allows continuous operation, a short-term rating that allows operation for a certain period of time (load time) from room temperature, and a repetitive rating that allows operation for a certain period of time (load time rate) within a specified cycle time.

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

[0004] Patent No. 5628994

[0005] Simply estimating the time until overheating does not allow easy understanding of the safety and remaining capacity of the motor's operation. Specifically, when adjusting a setting value such as motor speed to minimize the margin for overheating and perform machining as efficiently as possible, it is not easy to determine how much to increase or decrease the setting value. For this reason, a technology that allows easy understanding of the motor's status is desired.

[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 according to an operating program; an output value acquisition unit that acquires an output value of the motor; a status information acquisition unit that acquires status information indicating a state of the motor that 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 status information acquired at a predetermined timing and stores them as history information with an identifier attached; and a graph display unit that displays a graph in which markers indicating combinations of the rotation speed and the output value are plotted in a graph area with one axis representing the rotation speed and the other axis representing the output value, with a label indicating the identifier attached.

[0007] According to the present disclosure, the state of the motor can be easily grasped.

[0008] It is a block diagram showing the configuration of a machine tool equipped with a motor monitoring device according to a first embodiment of the present disclosure.It is a diagram showing an example of a display by the motor monitoring device of FIG.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Fig. 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.

[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 a screen in accordance with the numerical control device 10, and an input device 40 which a user uses 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 in accordance with an operation program (called a machining program in the numerical control device) so that the machine tool 1 can perform predetermined machining on the workpiece. 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 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 a workpiece. The spindle motor 20 operates according to the operation program as described above, but the load may vary depending on the machining situation, regardless of the rotation speed. The rotation speed detector 21, current detector 22, and temperature detector 23 may each be configured using 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 that allows a user to input information to the numerical control device 10, and may have a well-known configuration such as a keyboard or a 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 memory unit 11, a motor control unit 12 that controls the operation of the motor that drives the drive axis of the machine tool 1, including the spindle motor 20, and a motor monitoring unit 13 that performs the functions of the motor monitoring device according to the present disclosure.

[0015] The program storage unit 11 stores an operation program to be executed by the machine tool 1. The operation program includes a plurality of blocks, each of which specifies a unit operation of the machine tool 1. Each block includes one or more words each made up of a combination of a plurality of characters. Generally, each block is initially assigned a sequence number to identify the block.

[0016] In accordance with the operation program, motor control unit 12 executes the machining procedure described in the operation program by controlling spindle motor 20 and the motors of the other drive axes of machine tool 1. The configuration of motor control unit 12 is similar to that of a well-known numerical control device, and therefore a detailed description thereof will be 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, from the program storage unit 11, an operation program that specifies the operation to be monitored of 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 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 ​​of the spindle motor 20, such as a current value, a power value, and a torque value. In the present embodiment, the output value acquisition unit 133 acquires the current value of the spindle motor 20 from the current detector 22 and uses the power value calculated from the current value as the output value. However, the output value acquisition unit 133 may be configured to use a detected value such as a current value as the output value as is. The output value acquisition unit 133 may acquire an output value or a value required to calculate an output value from the motor control unit 12. Furthermore, the output value acquisition unit 133 may acquire two or more types of output values.

[0021] The status information acquiring unit 134 acquires status information indicating the status of the spindle motor 20 other than the rotation speed and output value. In this embodiment, the status information acquiring unit 134 calculates an estimated time until the spindle motor 20 reaches an overheat temperature if the spindle motor 20 maintains its rotation 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 acquiring unit 133, and uses this estimated time as one piece of status information. The status information acquiring unit 134 may also use other indicators indicating the status of the spindle motor 20 as alternative or additional status information. For example, the winding temperature of the spindle motor 20 may be used directly as status information. Furthermore, the status information may include program position information that identifies a position in the operation program, modal information that specifies the operation of the spindle motor 20, etc. Examples of program position information include a sequence number, a line number, a block number, etc. Modal information includes commands extracted from the operation program (not limited to those that directly specify the operation of the spindle motor 20, but also including commands that may affect the operation of the spindle motor 20, such as commands that specify tools), setting values ​​of the numerical control device 10, etc.

[0022] The history information storage unit 135 associates the rotation speed, output value, and status information acquired at a predetermined timing and stores the information as history information with an identifier. In other words, the history information storage unit 135 stores the rotation speed, output value, and status information of the spindle motor 20 at the same timing as one record, and adds a unique identifier to each record. A serial number or time may be used as the identifier.

[0023] The timing for acquiring the rotation speed, output value, and status information stored as history information by the history information storage unit 135 may include timing specified by the user, when the combination of the rotation speed and output value reaches a predetermined load level, and when an abnormality is detected. Saving history information at timing specified by the user allows the user to check the status of the spindle motor 20 in detail at a time of interest. Furthermore, saving 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 allows the user to save information that is desirable for the user to check. The load level for which history information is saved may be the maximum load level at which operation is permitted, for example, a zone above a specific time rating and below an instantaneous rating, among zones set to divide the graph area into multiple zones for the combination of rotation speed and output value. In FIG. 2 , the graph area is divided into four zones by the continuous rating, time rating, and maximum output, respectively, indicated by dotted lines: a load zone where continuous operation is possible, a load zone where intermittent operation is possible, a load zone where short-term operation is permitted as an exception, and an operation zone where even short-term operation is not permitted.

[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 specified timing (for example, the time closest to the specified timing and a certain number of times just before) as one or more pieces of history information. By storing a certain number of consecutive pieces of information at regular intervals in this way, the user can check the rate of change in the operating status, and therefore can more appropriately understand the status of the spindle motor 20.

[0025] The graph display unit 136 displays a graph in which markers indicating combinations of rotation speeds and output values ​​stored in the history information storage unit 135 are plotted in a graph area with rotation speeds on one axis and output values ​​on the other axis, with labels indicating identifiers attached. In the example shown in Figure 2, the labels indicating identifiers are attached adjacent to the markers, but they may also be enlarged and displayed on the markers, or may be displayed separated from the markers using leader lines. Displaying such a graph allows the user to visualize the load on the spindle motor 20 while easily identifying corresponding history information, i.e., information other than rotation speeds and output values.

[0026] The graph display unit 136 preferably displays a graph so that the user can select a marker to display. The selection of a marker may be performed indirectly by selecting a label. In FIG. 2, a marker labeled with an identifier "3" is selected in the graph display unit 136, 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 by the marker displayed by the graph display unit 136, the user can easily identify the history information and the portion of the operating program to be checked. Conversely, the graph display unit 136 may identifiably display a marker corresponding to the history information displayed by the history information display unit 137.

[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 Fig. 2, the content of the history information assigned the identifier "3" is displayed in the history information display unit 137. Furthermore, the history information display unit 137 may be provided with buttons for forwarding and backwarding the history information, so that the history information can be selected. In this way, by correlating the display of the history information display unit 137 with the graph display unit 136, operability can be improved.

[0028] The program display unit 138 displays at least a portion of the operation program. It is preferable that the program display unit 138 provides a user interface that allows the user to edit the displayed operation program. In other words, the program display unit 138 may be configured to reflect the edited contents of the operation program confirmed in the program display unit 138 in the contents stored in the program storage unit 11. It is preferable that the program display unit 138 identifiably displays a portion identified by program position information in the history information corresponding to a marker selected by the user in the graph display unit 136. In FIG. 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 its surroundings are displayed, and the portion corresponding to the selected marker identifier "3" is identifiably displayed. In this way, by correlating the display of the program display unit 138 with 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 rotation speeds, output values, and status information acquired at predetermined timings and stores them as history information with identifiers, and a graph display unit 136 that displays a graph in which markers indicating combinations of rotation speeds and output values ​​are plotted with labels indicating identifiers in a graph area with rotation speeds on one axis and output values ​​on the other. This makes it possible to easily grasp the status of the spindle motor 20, including status information other than rotation speeds and output values.

[0030] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of preferred effects resulting from the present invention, and the effects of the present invention are not limited to those described in the above-described embodiments.

[0031] The motor monitoring device according to the present disclosure may be provided independently of a numerical control device that controls a machine tool, and may be used to check the status of a motor other than the spindle motor of a machine tool, such as a motor for a kneader, etc. For example, the motor monitoring device according to the present disclosure may be a management computer that manages one or more numerical control devices, such as a controller for a kneader or the like, or a management computer that manages such a controller, to which the functionality of the motor monitoring unit of the above-described embodiment has been added.

[0032] In the motor monitoring device according to the present disclosure, the history information display section and the program display section may have any configuration, and the display position does not have to be selectable using a marker on the graph display section.

[0033] REFERENCE SIGNS LIST 1 Machine tool 10 Numerical control device (motor monitoring device) 11 Program storage unit 12 Motor control unit 13 Motor monitoring unit 131 Program acquisition unit 132 Rotation speed acquisition unit 133 Output value acquisition unit 134 Status information acquisition unit 135 History information storage unit 136 Graph display unit 137 History information display unit 138 Program display unit 20 Spindle motor 21 Rotation speed detector 22 Current detector 23 Temperature detector 30 Display device 40 Input device

Claims

1. a rotation speed acquisition unit that acquires the rotation speed of a motor that operates according to an operation program; an output value acquisition unit that acquires an output value of the motor; a state information acquiring unit that acquires state information indicating a state of the motor 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 a predetermined timing and stores the information as history information to which an identifier is added; a graph display unit that displays a graph in which a marker indicating a combination of the rotation speed and the output value is plotted in a graph area having one axis representing the rotation speed and the other axis representing the output value, with a label indicating the identifier attached; A motor monitoring device comprising:

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

3. 3. The motor monitoring device according to claim 1, wherein the predetermined timing includes a time when a combination of the rotation speed and the output value reaches a predetermined load level, and a time when an abnormality is detected.

4. The motor monitoring device according to claim 1 , wherein the predetermined timing includes a timing designated by a user.

5. The motor monitoring device according to claim 1 , further comprising a history information display unit that displays at least a portion of the history information corresponding to the marker selected by a user on the graph display unit.

6. A program display unit that displays at least a part of the operation program, the state information includes program location information identifying a location within the operating program; 3. The motor monitoring device according to claim 1, wherein the program display unit displays a portion of the history information that corresponds to the marker selected by the user on the graph display unit and that is specified by the program position information.

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

8. 3. The motor monitoring device of claim 1, wherein the status information includes modal information specifying operation of the motor.

9. The motor monitoring device according to claim 1 or 2, wherein the status information acquisition unit calculates, as one of the pieces of status information, an estimated time until the motor reaches an overheat temperature if the motor maintains the rotation speed and output value at that time.