Engine monitoring device

Abstract

A motor monitoring device according to one aspect of the present disclosure comprises: a program acquisition unit for acquiring a machining program comprising a plurality of blocks and to be executed by a machine tool; a rotational speed acquisition unit acquiring the rotational speed of a main shaft motor of the machine tool; an output value acquisition unit acquiring an output value of the main shaft motor; a program display unit for displaying program section information, which includes information specifying a section or position of the machining program; a chart display unit for displaying a chart in which markers, each indicating a combination of the rotational speed and the output value, are plotted in a chart area with one axis for the rotational speed and another axis for the output value.to be plotted; and an information storage unit for storing and assigning to each other the rotational speed and the output value as well as the blocks.

Description

TECHNICAL FIELD

[0001] The present invention relates to an engine monitoring device. TECHNICAL BACKGROUND

[0002] Motors such as spindle motors used in machine tools, where the load can vary significantly, are at risk of overheating if a high-load condition persists and heat accumulates. For such motors, various time ratings can be specified or set to ensure operation without overheating under specific conditions. For example, the time ratings specified in JIS-C4034-1 include continuous ratings that allow continuous operation; short-term ratings that allow operation for a certain period of time (load time) when operation begins at room temperature; and repetitive ratings that allow operation for a certain period of time (load time ratio) within a specified cycle time.

[0003] Such time ratings that vary with speed can be represented by a graph (characteristic curve) with the speed on the horizontal axis. To facilitate an easy understanding of the motor's load condition, it has been proposed to plot the combination of the speed and the motor's power or output at that time on a graph that indicates the characteristics of a plurality of time-rated outputs, with the speed on the horizontal axis and the output being a rated value. List of citationsPatent document

[0004] Patent Document 1: Unexamined Japanese Patent Application, Publication No. H10-90011 DISCLOSURE OF THE INVENTION Problems to be solved by the invention

[0005] Machine tools can be operated automatically by a numerical control device according to a machining program. In this case, the motor load condition changes with the progress of the machining program. Even if the load on the motor is relatively high at the moment, a short process can be completed without problems. Conversely, a long process can cause the motor to overheat, even if the load on the motor is not very high at the moment. Therefore, a technique is sought that enables an easy understanding of the relationship between the motor load condition and the machining program. Means to solve the problems

[0006] A motor monitoring device according to one aspect of the present disclosure includes: a program acquisition unit that acquires a machining program including a plurality of blocks executed by a machine tool; a rotational speed acquisition unit that acquires a rotational speed of a spindle motor of the machine tool; an output value acquisition unit that acquires an output value of the spindle motor; a program display unit that displays program section information including a section of the machining program or information indicating a position of the section; a chart display unit that displays a chart by plotting a mark indicating a combination of the rotational speed and the output value in a chart area.plots, with one axis representing the rotational speed and another axis representing the output value; and an information storage unit that stores the rotational speed and the output value in association with the blocks. Effects of the invention

[0007] According to the present disclosure, the relationship between the load condition of the motor and the machining program can be easily understood. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram illustrating the configuration of a machine tool incorporating a motor monitoring device according to the first embodiment of the present disclosure; and Fig. Figure 2 is a diagram illustrating a screen displayed by the engine monitoring device of Fig. 1 is displayed. PREFERRED MODE OF OPERATION FOR IMPLEMENTING THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Fig. 1 is a block diagram illustrating the configuration of a machine tool 1 incorporating a motor monitoring device according to the first embodiment of the present disclosure.

[0009] The machine tool 1 includes a numerical control device 10 as an embodiment of the motor monitoring device according to the present invention, a spindle motor 20, a speed detector 21 that detects the speed of the spindle motor 20, a current detector 22 that detects the current of the spindle motor 20, a temperature detector 23 that detects the winding temperature of the spindle motor 20, a display device 30 that displays a screen according to the numerical control device 10, and an input device 40 that is used by the user for inputting to the numerical control device 10.

[0010] The numerical control device 10 includes a memory, a processor (CPU), input / output interfaces, etc., and can be implemented by one or more computer devices executing appropriate control programs. The components of the numerical control device 10 described below are categorized based on the functions of the numerical control device 10 and need not be distinguishable in terms of their physical configuration and program configuration.

[0011] The spindle motor 20 is typically a motor that rotates a cutting tool or workpiece, where the load can potentially fluctuate independently of the speed based on the machining conditions. The speed detector 21, the current detector 22, and the temperature detector 23 can each be formed from known sensors.

[0012] The display device 30 is a known display that displays according to signals input from the numerical control device 10. The display device 30 can be integrated with the numerical control device 10. The input device 40 is a device used by the user to input information into the numerical control device 10 and can be formed from known components such as a keyboard or mouse. The input device 40 can also be integrated with the numerical control device 10. The input device 40 can also be integrated with the display device 30. Specifically, the display device 30 and the input device 40 can be a single input / output device such as a touch panel.

[0013] In the present embodiment, the numerical control device 10 includes: a program storage unit 11; a motor control unit 12 that controls the operation of motors that drive the drive axes 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.

[0014] The program storage unit 11 stores machining programs executed by the machine tool 1. Each machining program includes a plurality of blocks that specify the unit operations of the machine tool 1. Each block includes one or more words formed by combinations of a plurality of characters (letters). Typically, each block is preceded by a sequence number to identify the block.

[0015] The motor control unit 12 executes the machining operations described in the machining program by controlling the spindle motor 20 and the motors of other drive axes of the machine tool 1 according to the machining program. The configuration of the motor control unit 12 is the same as that of known numerical control devices, so a detailed description is omitted.

[0016] The engine monitoring unit 13 includes a program acquisition unit 131, a speed acquisition unit 132, an output value acquisition unit 133, a state value acquisition unit 134, an information storage unit 135, a program display unit 136, and a diagram display unit 137.

[0017] The program acquisition unit 131 acquires a machining 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 machining program into the working memory.

[0018] The speed detection unit 132 detects the speed of the spindle motor 20 from the speed detector 21. The speed detection unit 132 can also detect the speed of the spindle motor 20 via the motor control unit 12.

[0019] The output value acquisition unit 133 acquires the 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 is configured to acquire the current value of the spindle motor 20 from the current detector 22 and use the power value and the torque value calculated from the current value as the output value. However, the output value acquisition unit 133 may be configured to directly use the detected value, such as the current value, as the output value. The output value acquisition unit 133 may also acquire the output value or the values ​​necessary for calculating the output value from the motor control unit 12. The types of output values ​​acquired by the output value acquisition unit 133 may be one type or three or more types.

[0020] The state value acquisition unit 134 acquires state values ​​indicating the conditions of the spindle motor 20. In the present embodiment, the state value acquisition unit 134 calculates the estimated time until the spindle motor 20 reaches the overheating temperature when the rotational speed and output values ​​are maintained at present by the spindle motor 20, based on the winding temperature of the spindle motor 20 detected by the temperature detector 23 and the current value or the output value detected by the output value acquisition unit 133, and uses this estimated time as the first state value. The state value acquisition unit 134 calculates the torque of the spindle motor 20 based on the current value detected by the output value acquisition unit 133 and uses this torque as the second state value.The state value acquisition unit 134 may use other indicators of the conditions of the spindle motor 20 as state values, such as directly using the winding temperature of the spindle motor 20 as the state value.

[0021] The information storage unit 135 stores the rotational speed detected by the rotational speed detection unit 132, the output value detected by the output value detection unit 133, and the state value detected by the state value detection unit 134 in association with information identifying the corresponding block of the machining program detected by the program detection unit 131, such as sequence numbers or line numbers. In other words, the information storage unit 135 stores the rotational speed, the output value, and the state value in such a way that it is possible to identify which block of the machining program was executed when such a value was obtained. For example, the information storage unit 135 may be configured to store table data with the data items including the rotational speed, the output value, the state value, and the sequence number.

[0022] Typically, since the rotational speed, output value, and state value are acquired in short cycles, a plurality of combinations of rotational speed, output value, and state value can be acquired for one block. The information storage unit 135 can store one record per block as a unique key, thereby ensuring that no sequence numbers are duplicated in the data. In this case, the representative values ​​of the rotational speed, output value, and state value corresponding to each block are stored. The representative values ​​for the rotational speed, output value, and state value should preferably indicate a higher load among the values ​​corresponding to that block (the maximum value for rotational speed, current value, and temperature, and the minimum value for the estimated time) to ensure safety.

[0023] The program display unit 136 displays the program section information, which includes a section of the machining program or information indicating a position (such as a line number) of the section, on the display screen of the display device 30. In other words, the program display unit 136 creates data of at least a part of the screen displayed on the display device 30. Typically, as shown in Fig. 2, the program display unit 136 illustrates a program display area of ​​a certain size on the display screen of the display device 30 and displays the program section information including the machining program for lines permitted in the program display area. The program display unit 136 may display the machining program including information such as sequence numbers as the program section information, may extract and display only words specifying the operations of the machine tool from the machining program, may display only information indicating the position in the machining program, such as sequence numbers or line numbers, or may be configured to switch between these display modes.

[0024] The program display unit 136 preferably displays the position in the machining program that the user wishes to review in detail, selectable by units such as characters, words, or blocks, and may be configured to allow the user to select a plurality of blocks. The result of the user's selection of the position in the machining program may be reflected in the details displayed by the diagram display unit 137, as described below.

[0025] The program display unit 136 is preferably configured to accept modifications to the editing program. In other words, the program display unit 136 is preferably configured to allow the user to select and rewrite displayed words or text, and to store the rewritten editing program in the program storage unit 11.

[0026] The program display unit 136 may display the program section information in a manner that allows distinguishing the magnitude of the rate of change of at least one of the rotational speed and the output value. As a concrete example, the program display unit 136 may change the color or pattern of the characters, background, frame, etc., that display the information of the corresponding block based on the sub-range of the rate of change for which the limit value is set in advance or the sub-range for which the limit value is set relative to the maximum rate of change. Typically, the program display unit 136 may be configured to classify the rate of change of the rotational speed and the output value into three sub-ranges, respectively, and display the characters or background of the blocks with a small rate of change in blue, those with a moderate rate of change in yellow, and those with a large rate of change in red.The color of the block is preferably determined by the higher rate of change between the speed sub-range and the output value sub-range. In this way, the program display unit 136 displays the program section information in a manner that allows distinguishing the magnitude of the rate of change of at least one of the speed or the output value for each block, thereby making it easy to identify the blocks that cause a significant change of at least one of the speed or the output value. The rate of change may be the maximum rate of change within the block or may be the rate of change between the representative values ​​of the block.

[0027] The program display unit 136 can change the display mode for the program section information in a manner that enables differentiation of the load level determined based on the combination of the rotational speed and the output value. For example, the program display unit 136 can indicate the load zone to which the combination of the rotational speed and the output value associated with the displayed block belongs in the diagram display unit 137 by a color or pattern difference of the characters, background, or frame that display the block information.

[0028] The program display unit 136 can change the display mode based on the state value, thereby enabling the size of the state value to be differentiated either continuously or stepwise. The program display unit 136 can add characters indicating the sub-range of the value or the size of the state value to each block and can indicate the size of the state value through a color or pattern difference of the characters, background, or frame that display each block information. Typically, the possible range of the state value is divided into three or more sub-ranges, and the program display unit 136 can be configured to change the display mode of the block based on the sub-range to which the state value belongs. In this case, the program display unit 136 can be capable of setting the threshold value of the state value that changes the display mode of the block according to user input.

[0029] As described below, the program display unit 136 can distinguishably display the block associated with the combination of the rotational speed and the output value whose difference from the coordinate position selected in the chart display unit 137 is less than or equal to a predetermined margin amount. Clearly displaying the block that produces a result that the user will notice in the chart display unit 137 allows the user to easily understand the problematic points in the machining program. By setting a margin amount for selecting a coordinate position, blocks that include combinations of an approximate rotational speed and an approximate output value can be suggested as candidates, enabling a rough selection.

[0030] The chart display unit 137 displays a chart on the display screen of the display device 30, in which markers representing combinations of the rotational speed and the output value are plotted in a chart area, with one axis representing the rotational speed and the other axis representing the output value. The chart display unit 137 can display a chart for a single output value or charts for a plurality of output values ​​side by side. The chart display unit 137 preferably provides the above-mentioned function of selecting a coordinate position.

[0031] In order to clarify the relationship between the machining program and the rotational speed and the output value, the program display unit 136 and the diagram display unit 137 preferably display the program section information and the diagram simultaneously on the same screen, as shown in Fig. 2. The program display unit 136 and the graph display unit 137 can display exclusively. In this case, when the graph display unit 137 switches to the screen display, the rotational speed and the output value corresponding to the block selected by the program display unit 136 can be plotted. Conversely, when the program display unit 136 switches to the screen display, the program section information corresponding to the rotational speed and the output value near the coordinate value selected by the graph display unit 137 can be highlighted.

[0032] The chart display unit 137 includes: a chart area setting unit 1371 that divides the chart area into a plurality of load zones and displays the load zones discriminably; and a plotting unit 1372 that plots the marks by changing the display mode based on the state value.

[0033] The diagram range setting unit 1371 divides the diagram range into a plurality of load zones with different load levels based on the plurality of time ratings of the spindle motor 20 with respect to the expected combinations of the rotational speed and the output value. This allows the user to easily understand the danger level of the spindle motor 20.

[0034] The diagram range setting unit 1371 preferably displays the plurality of load zones in a distinguishable manner using colors or patterns. Using colors or patterns makes it easy to understand which load zone the combination of the rotational speed and the output value belongs to. Using intuitive colors or patterns such as blue, yellow, and red to indicate the load level of the zones helps the user easily understand the danger level of the operating state of the spindle motor 20.

[0035] If the combination of the rotational speed and the output value of the spindle motor 20 remains within the continuous rating, the load on the spindle motor 20 can be maintained continuously in this operating state. Therefore, the upper limit of the lowest load zone is preferably represented by a curve indicating the continuous rating.

[0036] The graph range setting unit 1371 preferably forms a boundary of one of the plurality of load zones, preferably the lower boundary of the load zone with the highest load level, by connecting the maximum values ​​of the plurality of time ratings (such as short-term ratings and repetitive ratings with different load-time ratios) at the same rotational speed. The combination of the rotational speed and the output value plotted in the range beyond this boundary line refers to a dangerous output condition that may immediately cause a malfunction. Conversely, remaining within this boundary may indicate that short-term operation will not cause problems.

[0037] The diagram range setting unit 1371 can be configured to select the boundary of at least one of the plurality of load zones according to user input. Specifically, the boundaries of the load zones can be selected from the continuous rating, the maximum value of the plurality of time ratings, the plurality of short-term ratings with different load times, and the plurality of repetitive ratings with different load time ratios. This enables the setting of the load zones deemed appropriate based on the machining content of the machine tool 1, enabling a more appropriate understanding of the danger level of the spindle motor 20.

[0038] The plotting unit 1372 plots the combination of the rotational speed and the output value while indicating the magnitude of the state value by differences in the mark appearances such as shape, size, color, and pattern (as shown in Fig.2 with hatching within the circular outer boundary). This allows the user to understand the operating state of the spindle motor 20 at that time indicated by the rotational speed and the output value, as well as the state value that may be affected by the previous operating state of the spindle motor 20. For example, even if the state value indicates that the temperature of the spindle motor 20 is high, the user may be able to determine that there is no risk of a further increase in the temperature of the spindle motor 20 as long as the load level at that time is low. Conversely, even if the load level at that time is not very high, the user may be able to determine that overheating may soon occur if the operating state continues.The marker may include an outer boundary that differs slightly from the colors or patterns of the graph area, and a filled portion indicating the state value. Thus, the plotting unit 1372 indicates the state values ​​through the marker appearances, allowing the user to understand the operating state of the spindle motor 20 in a variety of ways.

[0039] The plotting unit 1372 can continuously change the size, color, etc. of the marker based on the state value; however, the possible range of the state value is divided into three or more sub-ranges, and the marker appearance is preferably determined based on which sub-range the state value belongs to. By gradually changing the marker appearance, the size of the state value can be presented more clearly. The sub-ranges of the state value can be preset or changed dynamically.For example, when the estimated time to reach the superheat temperature is used as the state value, the state value (estimated time) at the moment the combination of the rotational speed and the output value exceeds the continuous rating is used as the maximum value within the possible range of the state value, and a predetermined ratio to this maximum value can be used as the limit value for the sub-range of the state value. Typically, the plotting unit 1372 can be configured to divide the possible range of the state value into three sub-ranges by setting the limit values ​​to trisect the maximum value.

[0040] The plotting unit 1372 can be configured to set the threshold value of the state value that changes the mark appearance according to user input. The threshold value can be specified as an absolute value or as a ratio to the maximum value. The user can select the threshold value from a plurality of preset options. This allows the mark appearances to be changed at times deemed appropriate, taking into account the machining content of the machine tool 1, allowing the user to more accurately understand the danger level of the spindle motor 20.

[0041] As described above, when the position in the machining program is selected or modified in the program display unit 136, the plotting unit 1372 is preferably configured to selectively plot the rotational speed and the output value corresponding to the selected or modified position in the machining program. Specifically, when the user selects a plurality of blocks in the program display unit 136, the plotting unit 1372 preferably plots the rotational speed and the output value corresponding to the plurality of selected blocks simultaneously or continuously plots and animates them. This allows the user to easily check the rotational speed, the output value, and the state value of the spindle motor 20 in the blocks to be checked or modified in the machining program.

[0042] The numerical control device 10 according to the present embodiment includes: the information storage unit 135 that stores the rotational speed and the output value of the spindle motor 20 in association with the blocks of the machining program; the program display unit 136 that displays the program section information indicating a section of the machining program or a position of the section; and the chart display unit 137 that displays a chart by plotting marks indicating combinations of the rotational speed and the output value in a chart area, with one axis representing the rotational speed and the other axis representing the output value. This enables easy understanding of the relationship between the load condition of the motor plotted on the chart and the currently executing program.

[0043] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above-described embodiments. The effects described in the above embodiments are merely examples of the preferred effects obtained from the present invention, and the effects of the present invention are not limited to those described in the above embodiments.

[0044] The motor monitoring device according to the present disclosure can be provided independently of the numerical control device that controls the machine tool. For example, the motor monitoring device according to the present disclosure can add the functions of the motor monitoring unit described in the above embodiments to a management computer that controls one or more numerical control devices.

[0045] The engine monitoring device according to the present disclosure may not include a state value acquisition unit, and the chart display unit may not include the function of changing the appearance of the markers. The engine monitoring device according to the present disclosure may not include the function of modifying the machining program. List of reference symbols 1 machine tool 10 numerical control or regulation device (engine monitoring device) 11 Program storage unit 12 Engine control or regulation unit 13 Engine monitoring unit 131 Program acquisition unit 132 Speed ​​detection unit 133 Output value acquisition unit 134 Condition value recording unit 135 Information storage unit 136 Program display unit 137 Diagram display unit 1371 Diagram range setting unit 1372 application unit 20 spindle motor 21 Speed ​​detector 22 Current detector 23 Temperature detector 30 Display device 40 Input device QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 10-90011

[0004]

Claims

[1] Engine monitoring device comprising: a program acquisition unit that acquires a machining program including a plurality of blocks executed by a machine tool; a speed detection unit that detects a speed of a spindle motor of the machine tool; an output value detection unit that detects an output value of the spindle motor; a program display unit that displays program section information including a section of the machining program or information indicating a position of the section; a chart display unit that displays a chart by plotting a mark indicating a combination of the rotational speed and the output value in a chart area, with one axis representing the rotational speed and another axis representing the output value; and an information storage unit which stores the speed and the output value in association with the blocks. [2] The engine monitoring device according to claim 1, wherein the program display unit and the chart display unit simultaneously display the program section information and the chart on the same screen. [3] An engine monitoring device according to claim 1 or 2, wherein the information storage unit stores maximum values ​​of the rotational speed and the output value for each of the blocks. [4] Engine monitoring device according to one of claims 1 to 3, wherein the program display unit displays a position in the machining program in a manner selectable by a user, and the diagram display unit plots the speed and output value corresponding to the blocks containing the position selected via the program display unit. [5] Engine monitoring device according to claim 4, wherein the program display unit allows the user to select the plurality of blocks, and the graph display unit plots the rotational speed and the output value corresponding to the plurality of blocks selected via the program display unit simultaneously or continuously. [6] Engine monitoring device according to one of claims 1 to 4, wherein the program display unit accepts a change to the machining program, and the graph display unit plots the speed and the output value corresponding to the program section information including a section modified in the program display unit. [7] The engine monitoring device according to any one of claims 1 to 6, wherein the program display unit displays the program section information in a manner that enables discrimination of a magnitude of a rate of change of at least one of the rotational speed and the output value. [8] The engine monitoring device according to any one of claims 1 to 7, wherein the program display unit displays the program section information in a manner that enables discrimination of a load level determined based on the combination of the rotational speed and the output value. [9] Engine monitoring device according to one of claims 1 to 8, wherein the diagram display unit accepts a selection of a coordinate position in the diagram area, and the program display unit distinguishably displays the blocks associated with the combination of the rotational speed and the output value whose difference from the selected coordinate position is less than or equal to a predetermined margin amount. [10] Engine monitoring device according to one of claims 1 to 9, further comprising: a state value detecting unit that detects a state value indicating a condition of the spindle motor, wherein at least one of the program display unit or the chart display unit changes a display mode based on the state value. [11] An engine monitoring device according to claim 10, wherein the diagram display unit includes: a diagram area setting unit that divides the diagram area into a plurality of load zones with different load levels based on a plurality of time ratings of the spindle motor with respect to expected combinations of the rotational speed and the output value, and displays the plurality of load zones in a distinguishable manner; and a plotting unit that plots the marker by changing an appearance of the marker based on the state value. [12] The engine monitoring device according to claim 10 or 11, wherein a possible range of the condition value is divided into three or more sub-ranges, and the program display unit changes a display mode of the blocks based on which sub-range the condition value belongs to. [13] The engine monitoring device according to claim 12, wherein the program display unit is capable of setting a threshold value of the state value that changes the display mode of the blocks according to a user input. [14] The motor monitoring device according to any one of claims 10 to 13, wherein the state value detecting unit calculates, as the state value, an estimated time until the spindle motor reaches an overheating temperature in the case that the spindle motor maintains the rotational speed and the output value at present values.

Images