Numerical Control Device

Abstract

The numerical control device according to the present disclosure is a numerical control device that controls a servo motor (71x) and a braking device (711x) that applies a brake to the servo motor and causes a machine tool to perform vibration cutting, and has an estimation unit (482) that estimates deterioration of the braking device (711x) based on the number of vibrations of micro-vibrations associated with the vibration cutting.

Description

[Technical field]

[0001] The present disclosure relates to a numerical control device for controlling vibration cutting. [Background technology]

[0002] A servo motor controlled by a numerical control device is usually equipped with a brake device to prevent, for example, a slide table that can move in the vertical direction from falling when the power is turned off. The components that make up this brake device wear out due to repeated braking operations, and the brake device reaches the end of its life due to the wear of these components. For this reason, it is important to understand the deterioration and lifespan of the brake device in advance and prepare for malfunctions and unexpected breakdowns.

[0003] Various techniques have been proposed for understanding the deterioration of brake devices. For example, Patent Document 1 discloses a technique for calculating the workload of an electromagnetic brake, calculating the total workload of the electromagnetic brake by multiplying and accumulating the workload of the electromagnetic brake each time a machine tool is braked to make an emergency stop, and monitoring the lifespan of the electromagnetic brake based on the total workload of the electromagnetic brake. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-155199 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned Patent Document 1 is limited to monitoring deterioration caused by braking operation, and cannot grasp deterioration caused by vibration cutting of, for example, a fastening hub that wears out due to vibrations during vibration cutting, or a brake device that has components such as friction plates.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a numerical control device that is capable of grasping deterioration caused by vibration cutting of a brake device that applies a brake to a servo motor. [Means for solving the problem]

[0007] In order to achieve the above object, the numerical control device according to the present disclosure includes a servo motor. Ta A numerical control device for controlling a machine tool to perform vibration cutting, the numerical control device being configured to: Braking the servo motor The brake device includes an estimation unit that estimates deterioration of the brake device. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a numerical control device capable of grasping deterioration caused by vibration cutting of a brake device that applies a brake to a servo motor. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a numerical control device according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining an example of implementation of a brake device according to an embodiment. [Diagram 3] 5A to 5C are diagrams for explaining the operation of the brake device according to the embodiment. [Figure 4] 5A and 5B are diagrams for explaining an example of the structure of a fastening hub of the brake device according to the embodiment. [Diagram 5] FIG. 4 is a diagram showing an example of processing executed by the numerical control device according to the embodiment. [Figure 6] 13 is a diagram illustrating an example of information showing a relationship between an execution time of vibration cutting according to the embodiment and an amount of wear in a fastening hub provided in a brake device. FIG. [Figure 7] FIG. 4 is a diagram showing an example of a display screen output by the numerical control device according to the embodiment. [Figure 8] FIG. 4 is a diagram showing operating conditions of vibration cutting control according to the embodiment. [Figure 9]5A to 5C are schematic diagrams showing examples of vibration waveforms before and after a change in operating conditions of vibration cutting control according to the embodiment. [Figure 10] FIG. 11 is a diagram showing another example of the display screen output by the numerical control device according to the embodiment. [Figure 11] FIG. 13 is a diagram showing a configuration example of a numerical control device according to a modified example. [Figure 12] FIG. 11 is a diagram showing an example of processing executed by a numerical control device according to a modified example. [Figure 13] 13A and 13B are diagrams for explaining the operation of a brake device according to another embodiment. [Figure 14] FIG. 4 is a diagram showing an example of a hardware configuration of a control and calculation unit according to the embodiment and modified examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a numerical control device according to an embodiment will be described in detail with reference to the drawings, however, the present invention is not limited to these embodiments.

[0011] Embodiments. Fig. 1 is a block diagram showing an example of a numerical control device 1 according to an embodiment. The numerical control (NC) device 1 shown in Fig. 1 is, for example, a computer that executes control of vibration cutting, which performs cutting while vibrating a tool, for a machine tool that performs cutting. The numerical control device 1 has an input operation unit 2, an output unit 3, and a control calculation unit 4. Fig. 1 also shows, for example, a drive unit 7 that is a component of the machine tool. Note that the drive unit 7 may be an element independent of the machine tool.

[0012] The driving unit 7 is connected to the control calculation unit 4, and is a mechanism for driving at least one of a tool for machining a workpiece to be machined by the machine tool and the workpiece itself. In this embodiment, the driving unit 7 is a mechanism for machining the workpiece by driving a tool in two directions, a direction parallel to the X-axis direction and a direction parallel to the Z-axis direction, while rotating the workpiece, for example. The X-axis direction is, for example, a vertical direction, that is, the direction of gravity. The Z-axis direction is, for example, a horizontal direction. In this embodiment, the central axis of the workpiece is defined as the Z-axis, and the direction perpendicular to the Z-axis is defined as the X-axis. The axial direction is not limited to the above directions, since it depends on the mechanical configuration.

[0013] The driving unit 7 has an X-axis servo motor 71x, a detector 72x, and an X-axis servo control unit 73x. The X-axis servo motor 71x moves the tool along the X-axis defined on the numerical control device 1. The detector 72x detects the position and speed of the X-axis servo motor 71x. The X-axis servo control unit 73x performs feedback control of the X-axis servo motor 71x based on a command from the numerical control device 1 and position information and speed information detected by the detector 72x. Regarding the feedback control, feedback is also referred to as FB below. The X-axis servo control unit 73x realizes the operation of the tool in the X-axis direction by performing FB control of the X-axis servo motor 71x. In addition, the driving unit 7 outputs the position information detected by the detector 72x to the control calculation unit 4 as the FB vibration movement amount of the X-axis.

[0014] The driving unit 7 also has a Z-axis servo motor 71z, a detector 72z, and a Z-axis servo control unit 73z. The Z-axis servo motor 71z moves the tool along the Z-axis defined on the numerical control device 1. The detector 72z detects the position and speed of the Z-axis servo motor 71z. The Z-axis servo control unit 73z performs FB control of the Z-axis servo motor 71z based on a command from the numerical control device 1 and position information and speed information detected by the detector 72z. The Z-axis servo control unit 73z controls the operation of the tool in the Z-axis direction by performing FB control of the Z-axis servo motor 71z. The driving unit 7 also outputs the position information detected by the detector 72z to the control calculation unit 4 as the FB vibration movement amount of the Z-axis.

[0015] The machine tool may have one tool rest, or two or more tool rests. When the machine tool has two or more tool rests, the drive unit 7 has two or more sets of an X-axis servo motor 71x, a detector 72x, and an X-axis servo control unit 73x, a Z-axis servo motor 71z, a detector 72z, and a Z-axis servo control unit 73z for each tool rest.

[0016] The drive unit 7 also has a spindle motor 71s, a detector 72s, and a spindle control unit 73s. The spindle motor 71s rotates a spindle that rotates a machined workpiece. The detector 72s detects the position and rotation speed of the spindle motor 71s. The spindle control unit 73s performs FB control of the spindle motor 71s based on a command from the numerical control device 1 and position information and speed information detected by the detector 72s. The spindle control unit 73s controls the rotation operation of the machined workpiece by performing FB control of the spindle motor 71s. The rotation speed detected by the detector 72s corresponds to the rotation speed of the spindle motor 101s.

[0017] The machine tool may simultaneously machine two or more workpieces. When the machine tool simultaneously machines two or more workpieces, the drive unit 7 includes two or more sets of a spindle motor 71s, a detector 72s, and a spindle control unit 73s. In this case, the machine tool includes, for example, two or more tool rests.

[0018] The input operation unit 2 is a means for inputting information to the control calculation unit 4. The input operation unit 2 is configured with input means such as a keyboard, a button, a mouse, etc. The input operation unit 2 accepts, for example, input of commands, etc. by an operator to the numerical control device 1, input of processing program numbers, etc., and input of parameters, etc. related to vibration cutting, and inputs them to the control calculation unit 4.

[0019] The output unit 3 is a means for outputting information from the control calculation unit 4. The output unit 3 is configured with a display means such as a liquid crystal display device. The output unit 3 displays information processed by the control calculation unit 4 on a display screen. In the embodiment, the output unit 3 is provided with a display means, but is not limited to this configuration. For example, the output unit 3 may be a display device or a display device of a computer connected to a network when the numerical control device 1 is connected to the network. The output unit 3 may also be an audio device such as a speaker.

[0020] The control and calculation unit 4 includes an input control unit 41, a data setting unit 42, a storage unit 43, an output control unit 44, an analysis processing unit 45, a control signal processing unit 46, and a PLC (Programmable Logic The PLC circuit unit 47 includes an interpolation processing unit 48, an acceleration / deceleration processing unit 49, and an axis data input / output unit 50. In this embodiment, the PLC circuit unit 47 is disposed inside the control calculation unit 4, but the PLC circuit unit 47 may be disposed outside the control calculation unit 4.

[0021] The input control unit 41 accepts information input from the input operation unit 2. The data setting unit 42 stores the information accepted by the input control unit 41 in the storage unit 43. That is, the input information accepted by the input operation unit 2 is written in the storage unit 43 via the input control unit 41 and the data setting unit 42.

[0022] The storage unit 43 has a parameter storage area 431 , a processing program storage area 432 , a display data storage area 433 , and a shared area 434 .

[0023] The parameter storage area 431 stores parameters used in the processing of the control calculation unit 4, specifically, control parameters for operating the numerical control device 1, servo parameters, tool data, and parameters related to vibration cutting.

[0024] A machining program including one or more blocks used for machining a workpiece is stored in the machining program storage area 432. In this embodiment, the machining program includes a movement command for moving a tool, a rotation command for rotating a spindle, and the like.

[0025] The display data memory area 433 stores screen display data to be displayed on the output unit 3. The screen display data is data for displaying information on the output unit 3. The shared area 434 stores data that is temporarily used when the control calculation unit 4 executes each process. For example, the machining program number accepted by the input operation unit 2 is written into the shared area 434 of the memory unit 43 via the input control unit 41 and the data setting unit 42.

[0026] The output control unit 44 causes the output unit 3 to display the screen display data stored in the display data storage area 433 of the storage unit 43 .

[0027] In the control calculation unit 4, the analysis processing unit 45, the control signal processing unit 46, and the interpolation processing unit 48 are connected to one another via the storage unit 43, and information is written and read out via the storage unit 43. In the following, when describing the writing and reading of information between the analysis processing unit 45, the control signal processing unit 46, and the interpolation processing unit 48, the mediation of the storage unit 43 may be omitted.

[0028] The analysis processing unit 45 is connected to the storage unit 43. The analysis processing unit 45 refers to the machining program number written in the shared area 434 of the storage unit 43. When the analysis processing unit 45 receives a selected machining program number from the shared area 434, it reads out the selected machining program from the machining program storage area 432 and performs an analysis process for each block (each line) of the machining program. The analysis processing unit 45 analyzes an S code which is a spindle motor rotation speed command, a G code which is a command related to axis movement, etc., and an M code which is a machine operation command, etc. When the analysis processing unit 45 finishes the analysis process for each line of the machining program, it writes the analysis results of the S code, G code, M code, etc. into the shared area 434 of the storage unit 43.

[0029] Furthermore, when an S code is included in the machining program, the analysis processing unit 45 analyzes the S code to obtain the spindle speed, which is the rotation speed of the spindle. Then, the analysis processing unit 45 writes the obtained spindle speed in the shared area 434 of the storage unit 43.

[0030] Furthermore, when a machining program includes a G-code, the analysis processing unit 45 analyzes the G-code to obtain movement conditions, which are conditions for tool feed for moving the tool to the machining position. The movement conditions are indicated by the speed in the X-axis direction and the Z-axis direction for moving the tool rest, and the positions in the X-axis direction and the Z-axis direction for moving the tool rest, etc. Then, the analysis processing unit 45 writes the obtained movement conditions in the shared area 434 of the storage unit 43.

[0031] Furthermore, when the machining program includes a G-code for vibration cutting, the analysis processing unit 45 analyzes the G-code to obtain vibration conditions including a vibration frequency that is a frequency at which the tool is vibrated in vibration cutting and an amplitude at which the tool is vibrated in vibration cutting. Then, the analysis processing unit 45 writes the obtained vibration conditions in the shared area 434 of the storage unit 43.

[0032] The control signal processing unit 46 is connected to the PLC circuit unit 47, and receives signal information from the PLC circuit unit 47, such as a relay that operates the machine of the machine tool. The control signal processing unit 46 writes the received signal information into the shared area 434 of the memory unit 43. The interpolation processing unit 48 refers to this signal information during machining operation. When an auxiliary command is output to the shared area 434 by the analysis processing unit 45, the control signal processing unit 46 reads out the auxiliary command from the shared area 434 and sends it to the PLC circuit unit 47. The auxiliary command is a command other than a command that operates a drive axis, which is a numerically controlled axis. The auxiliary command is, for example, an M code or a T code.

[0033] The interpolation processing unit 48 is connected to the storage unit 43 and the acceleration / deceleration processing unit 49. The interpolation processing unit 48 refers to the shared area 434 of the storage unit 43, and when the analysis processing unit 45 writes the above-mentioned movement condition and the above-mentioned vibration condition to the shared area 434, the interpolation processing unit 48 reads out the above-mentioned movement condition and the above-mentioned vibration condition, and generates an X-axis command vibration movement amount which is a command vibration movement amount in the X-axis direction and a Z-axis command vibration movement amount which is a command vibration movement amount in the Z-axis direction using the read movement condition and vibration condition. Note that the X-axis command vibration movement amount and the Z-axis command vibration movement amount are also collectively referred to simply as a command vibration movement amount. The interpolation processing unit 48 writes the generated command vibration movement amount to the shared area 434 of the storage unit 43 and outputs it to the acceleration / deceleration processing unit 49. Furthermore, when the interpolation processing unit 48 acquires the FB vibration movement amount from the acceleration / deceleration processing unit 49, it writes the acquired FB vibration movement amount to the shared area 434 of the storage unit 43.

[0034] The acceleration / deceleration processing unit 49 is connected to the interpolation processing unit 48 and the axis data input / output unit 50. The acceleration / deceleration processing unit 49 converts the command vibration movement amount output from the interpolation processing unit 48 into a movement command per unit time taking into account acceleration / deceleration according to a pre-specified acceleration / deceleration pattern, and outputs this converted movement command to the axis data input / output unit 50. In addition, the acceleration / deceleration processing unit 49 outputs the FB vibration movement amount output from the axis data input / output unit 50 to the interpolation processing unit 48.

[0035] The axis data input / output unit 50 is connected to the acceleration / deceleration processing unit 49 and the driving unit 7. The axis data input / output unit 50 outputs the movement command per unit time output from the acceleration / deceleration processing unit 49 to the driving unit 7. In addition, the axis data input / output unit 50 outputs the FB vibration movement amount output from the driving unit 7 to the acceleration / deceleration processing unit 49.

[0036] Next, an example of mounting the brake device will be described. In this embodiment, the X-axis servo motor 71x that moves the tool in the X-axis direction, i.e., the vertical direction, is equipped with a brake device. The brake device of the X-axis servo motor 71x may be built into the X-axis servo motor 71x or may be attached externally. Also, the brake device may be provided in a servo motor other than the X-axis servo motor 71x. For example, a servo motor that can be controlled so that the tool movement direction includes a vertical component is provided with a brake device.

[0037] Fig. 2 is a diagram for explaining an example of mounting the brake device according to the embodiment. According to Fig. 2, the X-axis servo motor 71x has a brake device 711x, a motor body 712x, and a shaft 713x. The X-axis servo motor 71x is provided with a detector 72x. The X-axis direction shown in Fig. 2 represents, for example, the vertical direction.

[0038] Also, according to FIG. 2, a feed mechanism 81x is connected to the X-axis servo motor 71x. The feed mechanism 81x has a coupling 811x, a ball screw 812x, an operating unit 813x, and a ball screw support unit 814x. The coupling 811x has a function of connecting the X-axis servo motor 71x and the feed mechanism 81x. The ball screw 812x is disposed, for example, along the X-axis direction, and can rotate about the axis of the X-axis via the coupling 811x by the rotation of the X-axis servo motor 71x. The operating unit 813x can move in a direction along the X-axis, for example, in the up-down direction along the vertical direction, by the rotation of the ball screw 812x.

[0039] When the machine tool needs to be stopped due to an emergency stop or the like, the brake device 711x operates to stop the rotation of the motor main body 712x. At this time, the rotation of the ball screw 812x stops, and the vertical movement of the operating part 813x also stops.

[0040] The brake device 711x may be incorporated in the ball screw support portion 814x, not in the motor main body 712x. Although the X-axis has been described as being vertical, when a machine tool is used that performs machining with the X-axis set at an angle to the vertical, a brake device may be incorporated in a servo motor connected to the machine tool. When an axis other than the X-axis is set to include the vertical direction, a brake device may be incorporated in a servo motor that controls the other axis. Specifically, for example, when the Y-axis is set to include the vertical direction, a brake device may be incorporated in a servo motor that controls the Y-axis.

[0041] Next, the operation of the brake device having a fastening hub will be described. FIG. 3 is a diagram for explaining the operation of the brake device according to the embodiment. In FIG. 3, an example of a schematic cross-sectional structure parallel to the X-axis direction of the brake device 711x will be referred to, and the operation when the brake is ON and when the brake is OFF will be explained. Note that in FIG. 3, configurations other than those necessary for the explanation are omitted.

[0042] 3 includes an external gear 7111x, an internal gear 7112x, a friction plate 7113x, a fixed plate 7114x, a pressing plate 7115x, a housing 7116x, an electromagnetic coil 7117x, and a spring 7118x. The external gear 7111x and the internal gear 7112x are examples of a fastening hub in the claims.

[0043] The external gear 7111x meshes with the internal gear 7112x. A specific relationship between the external gear 7111x and the internal gear 7112x will be described below with reference to Fig. 4. Fig. 4 is a diagram for explaining an example of the structure of a fastening hub of the brake device according to the embodiment.

[0044] 4, for example, a through hole is formed in the external gear 7111x, and the shaft 713x is inserted through the through hole and fixed in place. The external gear 7111x rotates about the axis of the shaft 713x in synchronization with the rotation of the shaft 713x.

[0045] The external gear 7111x has a plurality of external teeth 7119x along its outer periphery. The internal gear 7112x has a plurality of internal teeth 7120x along its inner periphery. When the brake device 711x is used, the external gear 7111x and the internal gear 7112x are disposed in a positional relationship such that the plurality of external teeth 7119x mesh with the plurality of internal teeth 7120x shown in FIG. 4. At this time, the internal gear 7112x is disposed so as to be movable in the X-axis direction relative to the external gear 7111x. Then, when the brake is OFF, the internal gear 7112x rotates in synchronization with the rotation of the external gear 7111x.

[0046] Also, a backlash is set in advance between the external gear 7111x and the internal gear 7112x. Backlash is a gap intentionally provided at a portion where gears mesh with each other, and an optimal value is set in terms of, for example, the operation of the pressing plate 7115x, the brake specifications, and ease of assembly. The unit used to express backlash is, for example, "minutes." "Minute" is a unit that expresses the size of an angle that is 1 / 60th of "degrees" or "°." Note that in this embodiment, "°" is used as the unit to express backlash.

[0047] 3, the friction plate 7113x is connected to the internal gear 7112x. The friction plate 7113x rotates in synchronization with the rotation of the internal gear 7112x. The fixed plate 7114x has a function of restricting the movement of the friction plate 7113x in a direction away from the motor main body 712x when, for example, the brake is switched from OFF to ON.

[0048] In FIG. 3, when the brake is OFF, the electromagnetic coil 7117x is excited. That is, a current flows through the electromagnetic coil 7117x. At this time, an electromagnetic force larger than the elastic force of the spring 7118x is generated, and the pressing plate 7115x is attracted to the electromagnetic coil and moves toward the motor main body 712x. As a result, the friction plate 7113x is disposed at a position away from the fixed plate 7114x and the housing 7116x. At this time, there is no friction between the friction plate 7113x and the fixed plate 7114x and the housing 7116x, and the rotation of the friction plate 7113x is not restricted. Therefore, the external gear 7111x, the internal gear 7112x, and the friction plate 7113x can rotate together with the rotation of the shaft 713x.

[0049] 3, when the brake is ON, the current flowing through the electromagnetic coil 7117x is stopped, the electromagnetic force disappears, and the elastic force of the spring 7118x moves the pressing plate 7115x in a direction away from the motor main body 712x. As a result, the friction plate 7113x comes into contact with both the pressing plate 7115x and the fixed plate 7114x, and is sandwiched between them, and the rotation of the friction plate 7113x is stopped by the friction force. Therefore, the internal gear 7112x connected to the friction plate 7113x is stopped, and the rotation of the external gear 7111x and the shaft 713x, which is the motor shaft, is stopped via the gears.

[0050] Also, when the brake is ON, immediately after the X-axis servo motor 71x stops due to an emergency stop or the like, the operating part 813x shown in Fig. 2 drops by the amount of backlash provided between the external gear 7111x and the internal gear 7112x due to the action of gravity, and then stops. In this way, in the event of an emergency stop or the like, it is possible to stop the falling of the operating part 813x by the brake device 711x.

[0051] Here, in normal machining that is not vibration cutting, the movement of the X-axis due to machining is unidirectional, so for example, the external teeth 7119x of the external gear 7111x shown in FIG. 4 abut only one of the two internal teeth 7120x of the internal gear 7112x meshing with it. However, during vibration cutting, micro-vibrations caused by vibration cutting are superimposed on the movement of the machining, so the external teeth 7119x of the external gear 7111x repeatedly abut with both of the two internal teeth 7120x of the internal gear 7112x meshing with it, for example, at the period of the micro-vibrations caused by vibration cutting. For this reason, the multiple external teeth 7119x of the external gear 7111x and the multiple internal teeth 7120x of the internal gear 7112x wear down faster than when only normal machining is performed, and the life of the brake device comes sooner. If the servo motor continues to be used when the brake device has reached the end of its life, for example, in an emergency stop, the moving part 813x of the X-axis servo motor 71x may fall more than expected and collide with other machine structures, leading to a breakdown, and therefore the brake device needs to be replaced. In this way, in a numerical control device that causes a machine tool to perform vibration cutting, the fastening hubs of the brake device 711x, i.e., the external gear 7111x and the internal gear 7112x, are more affected by wear caused by vibration cutting than by wear caused by braking operation. Note that the micro-vibration associated with vibration cutting is vibration based on vibration conditions that vibrate the tool in vibration cutting, and is, for example, vibration transmitted to the brake device 711x while vibration cutting is being performed.

[0052] 1, the interpolation processing unit 48 according to this embodiment estimates the deterioration of the brake device based on the execution time of vibration cutting. Specifically, the interpolation processing unit 48 has a measurement unit 481, an estimation unit 482, a change unit 483, a waveform generation unit 484, and a vibration movement amount generation unit 485.

[0053] The measurement unit 481 measures the execution time of vibration cutting. Specifically, the measurement unit 481 stores the cumulative value of the time during which vibration cutting is performed, for example, in one brake device. The measurement unit 481 also determines whether the cumulative value of the execution time of vibration cutting is equal to or greater than a predetermined value.

[0054] The estimation unit 482 estimates the deterioration of the brake device 711x based on the number of vibrations of the micro vibrations associated with the vibration cutting. The estimation unit 482 estimates the deterioration of the brake device 711x based on, for example, the execution time of the vibration cutting measured by the measurement unit 481 and the vibration frequency of the vibration cutting. The vibration frequency of the vibration cutting is, for example, a frequency set to generate micro vibrations in the vibration cutting. The vibration number of the micro vibrations associated with the vibration cutting can be calculated from the execution time of the vibration cutting and the vibration frequency of the vibration cutting. The estimation unit 482 may count the vibration number based on the vibration waveform, which is the basic waveform of the vibration generated by the waveform generation unit 484, and accumulate the number of vibrations to obtain the vibration number of the micro vibrations associated with the vibration cutting.

[0055] Specifically, the estimation unit 482 refers to deterioration progress information indicating the relationship between the execution time of vibration cutting and the progress of deterioration of the brake device, and estimates the deterioration of the brake device 711x. At this time, the deterioration progress information also includes information regarding the vibration frequency of vibration cutting, which is a prerequisite for vibration cutting. The deterioration execution information indicates the degree of progress of deterioration of the brake device, which progresses as the execution time of vibration cutting becomes longer. The deterioration progress information is, for example, information indicating the relationship between the execution time of vibration cutting and the amount of wear in the fastening hub equipped in the brake device, that is, information indicating the relationship in which the wear in the fastening hub equipped in the brake device progresses as the execution time of vibration cutting becomes longer. The amount of wear in the fastening hub is, for example, the amount of wear occurring between the external gear 7111x and the internal gear 7112x. This amount of wear is recognized, for example, by the value of backlash between the external gear 7111x and the internal gear 7112x.

[0056] The information showing the relationship between the execution time of vibration cutting and the amount of wear in the fastening hub equipped with the brake device is information based on, for example, measured values ​​obtained in advance by conducting a durability test against the vibration cutting time on a brake device of the same type as the brake device 711x or a brake device having a similar mechanical configuration. Specifically, the information is based on the results of measuring the backlash of the fastening hub equipped with the brake device at multiple points along the execution time of vibration cutting. The brake device used in the durability test may be of the same type as the brake device 711x.

[0057] The vibration frequency on which the measurement is based is, for example, 166.7 Hz on average. The average of 166.7 Hz is realized by, for example, specifying a vibration frequency of 166.7 Hz, at least one vibration frequency lower than 166.7 Hz, and at least one vibration frequency higher than 166.7 Hz, and repeating the vibration cutting in stages so that the average vibration frequency of the vibration cutting performed within a predetermined time is 166.7 Hz. The measurement may be performed with the vibration frequency on which the measurement is based fixed to a predetermined value, for example, 166.7 Hz. The vibration frequency on which the measurement is based may not be included in the deterioration progress information. At this time, the estimation unit 482 may refer to the deterioration progress information and the vibration frequency on which the measurement is based associated with the deterioration progress information.

[0058] The change unit 483 changes the vibration conditions for vibration cutting based on the result of the estimation of deterioration estimated by the estimation unit 482. Specifically, the change unit 483 changes at least one of the number of vibrations (times) per one spindle rotation and the spindle rotation speed (r / min), for example, so as to extend the life of the brake device 711x, that is, to slow down the progression of deterioration of the brake device 711x. This changes the vibration frequency (Hz) of the micro-vibration accompanying the vibration cutting. More specifically, the change unit 483 reduces at least one of the number of vibrations (times) per one spindle rotation and the spindle rotation speed (r / min) compared to before the change, for example, so as to reduce the vibration frequency (Hz) of the micro-vibration accompanying the vibration cutting.

[0059] The waveform generating unit 484 generates a vibration waveform, which is a basic waveform of vibration, based on the information acquired from the analysis processing unit 45. When the changing unit 483 changes the vibration conditions, the waveform generating unit 484 generates a vibration waveform based on the changed vibration conditions.

[0060] The vibration movement amount generating unit 485 obtains, for example, a vibration movement amount of the X-axis using the vibration waveform generated by the waveform generating unit 484 and the tool movement path. Specifically, the vibration movement amount generating unit 485 obtains, for each vibration, a vibration forward position obtained by adding the amplitude of the vibration waveform to the tool movement path and a vibration backward position obtained by subtracting the amplitude of the vibration waveform from the tool movement path, and generates a vibration movement amount of the X-axis.

[0061] The vibration movement amount generated by the vibration movement amount generation unit 485 is sent to the drive unit 7 via the acceleration / deceleration processing unit 49 and the axis data input / output unit 50. The drive unit 7 performs vibration cutting by controlling, for example, the X-axis servo motor 71x based on the vibration movement amount sent from the vibration movement amount generation unit 485.

[0062] The process executed by the numerical control device 1 configured as above will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing an example of the process executed by the numerical control device according to the embodiment. In this embodiment, the vibration frequency of the vibration cutting before the change is assumed to be 166.7 Hz. Also, the vibration frequency of the vibration cutting, which is the premise of the information indicating the relationship between the execution time of the dynamic cutting referred to by the estimation unit 482 and the amount of wear in the fastening hub provided in the brake device, is assumed to be 166.7 Hz on average.

[0063] According to Fig. 5, when the vibration cutting process is started, the measurement unit 481 starts measuring the execution time of vibration cutting (step S51). Specifically, for example, when the vibration cutting mode is ON and the measurement unit 481 receives a command to start cutting, the measurement unit 481 starts measuring the execution time of vibration cutting. When the vibration cutting process ends, the measurement unit 481 ends measuring the execution time of vibration cutting. Specifically, for example, when the vibration cutting mode is ON and the measurement unit 481 receives a command to end cutting, the measurement unit 481 ends measuring the execution time of vibration cutting. At this time, the measurement unit 481 adds the time measured in step S1 to the cumulative time of execution time measured in the past, and stores the result as a new cumulative time of execution time.

[0064] When the measurement unit 481 finishes measuring the execution time of vibration cutting, the estimation unit 482 estimates the deterioration of the brake device 711x based on the execution time of vibration cutting and the vibration frequency of vibration cutting measured by the measurement unit 481 (step S52). Specifically, the estimation unit 482 estimates the deterioration of the brake device 711x, for example, by referring to deterioration progress information. The estimation unit 482 estimates the deterioration of the brake device 711x, for example, based on information indicating the relationship between the execution time of vibration cutting and the amount of wear in a fastening hub provided in the brake device.

[0065] FIG. 6 is a diagram showing an example of information showing the relationship between the execution time of vibration cutting according to the embodiment and the amount of wear in the fastening hub provided in the brake device. For the information shown in FIG. 6, the vibration frequency on which the measurement is based is set to an average of 166.7 Hz. According to FIG. 6, it can be seen that the backlash, that is, the backlash between the external gear 7111x and the internal gear 7112x, increases as the execution time of vibration cutting increases. The estimation unit 482 refers to the information showing the relationship between the execution time of vibration cutting and the amount of wear in the fastening hub, and obtains the backlash corresponding to the execution time of vibration cutting measured by the measurement unit 481, thereby estimating the amount of wear in the fastening hub provided in the brake device 711x. Note that the graph shown in FIG. 6 is a graph showing the relationship between the execution time of vibration cutting and the amount of wear in the fastening hub provided in the brake device when the vibration cutting process is continued at an average of 166.7 Hz, and at this time, the execution time of vibration cutting and the number of vibrations of the micro vibrations associated with vibration cutting are approximately proportional to each other. Therefore, the estimation unit 482 may use information indicating the relationship between the number of vibrations of the micro-vibrations associated with vibration cutting calculated from the average vibration frequency and the execution time of vibration cutting, and the amount of wear in the fastening hub provided with the brake device, as information for estimating the amount of wear in the fastening hub provided with the brake device 711x.

[0066] Furthermore, since the relationship between the execution time of vibration cutting and backlash varies depending on conditions such as the shaft diameter of the servo motor, the diameter of the ball screw, and the inertia of the moving parts, it is preferable to measure this in advance for each machine configuration.

[0067] In Fig. 5, when the estimation unit 482 estimates the amount of wear of the fastening hub included in the braking device 711x, it determines whether the estimated amount of wear is equal to or greater than a first threshold value (step S53). In Fig. 6, the first threshold value is, for example, Th1. This Th1 is set as, for example, a threshold value at which the braking device needs to be replaced.

[0068] In FIG. 5, when the estimation unit 482 determines that the estimated wear amount is equal to or greater than the first threshold value (Yes in step S53), the estimation unit 482 outputs a warning screen, for example, to the output unit 3 via the output control unit 44 (step S54).

[0069] Fig. 7 is a diagram showing an example of a display screen output by the numerical control device according to the embodiment. According to Fig. 7, a message prompting replacement of the brake device 711x is displayed on the output unit 3. Specifically, in Fig. 7, the estimation unit 482 displays, via the output control unit 44, on the output unit 3, for example, a graph SL1 showing the relationship between the execution time of vibration cutting performed in a state in which the brake device 711x is incorporated and the backlash, as well as a mark M1 showing the execution time of vibration cutting at the time of message output and a combination of the backlash value corresponding to this execution time of vibration cutting.

[0070] Here, the execution time of vibration cutting indicated by the mark M1 shown in Fig. 7 is equal to or greater than T1. Also, the backlash value indicated by the mark M1 shown in Fig. 7 is equal to or greater than a first threshold value Th1. Note that the mark M1 is not limited to a star shape as shown in Fig. 7. The mark M1 may be a circle, a square, a triangle, or any other shape that can be recognized by an operator or maintenance person.

[0071] Also, according to FIG. 7, the estimation unit 482 displays, via the output control unit 44, a message on the output unit 3 encouraging replacement of the brake device 711x, stating, “It is time to replace the brake device on the X-axis. We recommend replacing the brake device with a new one.”

[0072] This allows the operator or maintenance personnel to recognize that the brake device needs replacing and to replace the brake device for the target shaft. Also, the message urging replacement is displayed in parallel with the graph, allowing the operator or maintenance personnel to intuitively grasp the situation.

[0073] In addition, in FIG. 7, the estimation unit 482 displays both the graph display and the message prompting replacement, but it may display only the message prompting replacement.

[0074] When it is determined that the estimated wear amount is not equal to or greater than the first threshold (No in step S53), the estimation unit 482 determines whether or not the estimated wear amount is equal to or greater than a second threshold (step S55). In Fig. 6, the second threshold is, for example, Th2. This Th2 is set, for example, as a threshold indicating the time to extend the life of the brake device by changing the vibration conditions. Th2 is, for example, a value that is set in advance in the numerical control device when the machine tool is designed. Furthermore, Th2 may be, for example, a value that is set by an operator depending on the usage status and machining status of the machine tool.

[0075] 5, when the estimation unit 482 determines that the estimated wear amount is equal to or greater than the second threshold value (Yes in step S55), it notifies, for example, the change unit 483 to calculate the life extension condition of the brake device 711x. Upon receiving the notification to calculate the life extension condition, the change unit 483 calculates the life extension condition according to a predetermined condition (step S56).

[0076] Fig. 8 is a diagram showing a combination of vibration conditions according to the embodiment. Fig. 8 shows the number of vibrations (times) per one spindle rotation, the spindle rotation speed (r / min), and the vibration frequency (Hz) as items representing the operating conditions of vibration cutting control, i.e., the vibration conditions. The vibration frequency is uniquely determined by the number of vibrations per one spindle rotation and the spindle rotation speed. For this reason, the change unit 483 changes at least one of the number of vibrations per one spindle rotation and the spindle rotation speed so as to extend the life of the brake device 711x.

[0077] A specific example of calculation of life extension conditions will be described below with reference to Fig. 8. The vibration conditions before the change are "vibration frequency per spindle revolution: 2.5 times", "spindle rotation speed: 4000 r / min", and "vibration frequency: 166.7 Hz", as shown in Fig. 8.

[0078] 8, the change unit 483 changes the spindle rotation speed from 4000 r / min to 3428 r / min, for example, without changing the number of vibrations per one rotation of the spindle. This changes the vibration frequency from 166.7 Hz to 142.9 Hz. Note that the change unit 483 may, for example, receive an input of a desired life extension time, and change at least one of the number of vibrations per one rotation of the spindle and the spindle rotation speed by calculating backwards from the input life extension time.

[0079] FIG. 9 is a schematic diagram showing an example of vibration waveforms before and after a change in vibration conditions according to an embodiment. In FIG. 9, for example, the vibration frequency before the change is 166.7 Hz, and the vibration frequency after the change is 142.9 Hz. At this time, the vibration period CT1 before the change shown in FIG. 9 is 6.0 ms, and the vibration period CT2 after the change is 7.0 ms. In FIG. 9, the vibration waveform Cn of the nth period and the vibration waveform Cn+1 of the n+1th period are shown before and after the change in vibration conditions. Also, in FIG. 9, an idle region S that occurs between the nth period and the n+1th period is shown as a region for realizing chip breaking in vibration cutting before and after the change in vibration conditions. The idle region S is, for example, a region where cutting is not performed between the moving path of the tool and the workpiece, and where an idle region occurs, and where chip breaking of chips that have occurred up to that point can be executed.

[0080] As shown in Fig. 9, by changing the vibration conditions in this way, it is possible to lower the vibration frequency while generating an idle region S before and after the change. This makes it possible to calculate vibration conditions that enable vibration cutting, i.e., conditions for cutting while breaking up chips, while extending the life of the brake device 711x. Note that the vibration waveform shown in Fig. 9 may be based on either a vibration waveform based on a command value or a vibration waveform based on an FB value, as long as the vibration waveform based on the actual measurement value satisfies the conditions for vibration cutting.

[0081] In FIG. 5, when the change unit 483 calculates the life extension condition in step S56, it changes the vibration condition of the vibration cutting based on the calculated life extension condition (step S57). After that, the waveform generation unit 484 generates a vibration waveform based on the changed vibration condition, and the vibration cutting process is performed based on the generated vibration waveform. At this time, since the vibration frequency in the vibration cutting process is changed from 166.7 Hz to 142.9 Hz, for example, the period in which the external teeth 7119x of the external gear 7111x shown in FIG. 4 abuts on the two internal teeth 7120x of the internal gear 7112x meshing therewith becomes longer, and the number of abutments per unit time during which the vibration cutting is performed can be reduced. Specifically, that is, the amount of wear of the fastening hub of the brake device 711x per unit time during which the vibration cutting is performed can be reduced. At this time, it is expected that the life after the change will be extended by about 166.7 Hz / 142.9 Hz=1.17 times. In this way, it is possible to extend the life of the braking device 711x.

[0082] The change unit 483 may present the calculated life extension conditions to an operator or a maintenance person. Fig. 10 is a diagram showing another example of the display screen output by the numerical control device 1 according to the embodiment. According to Fig. 10, a message prompting a change of the vibration conditions of the X-axis servo motor 71x is displayed on the output unit 3.

[0083] Specifically, in Fig. 10, the change unit 483 displays, on the output unit 3 via the output control unit 44, for example, a graph showing the relationship between the execution time of vibration cutting in the brake device 711x and backlash, as well as a mark M2 showing the combination of the execution time of vibration cutting at the time of message output and the backlash value corresponding to this execution time of vibration cutting. Also, in Fig. 10, the change unit 483 displays, for example, an estimated graph DL1 represented by a dotted line via the output control unit 44. The estimated graph DL1 is a graph showing how much life can be extended if the changed vibration conditions are set at the time of message output.

[0084] Here, the execution time of vibration cutting indicated by mark M2 shown in Fig. 10 is equal to or greater than T2 and less than T1. Also, the backlash value indicated by mark M2 shown in Fig. 10 is equal to or greater than the second threshold value Th2 and less than the first threshold value Th1. Note that mark M2 is not limited to a star shape as shown in Fig. 10. Mark M2 may be a circle, a square, a triangle, or any other shape that can be recognized by an operator or maintenance person.

[0085] Also, according to FIG. 10, the change unit 483 displays on the output unit 3 via the output control unit 44 a message that prompts the user to change the vibration conditions in the X-axis servo motor 71x: "If the vibration conditions for vibration cutting are changed, the replacement time for the brake device of the X-axis can be extended by about 2 hours in terms of vibration cutting time. The time of the processing being performed can be extended by about 24 hours. Please arrange for a replacement brake device in advance." In this case, the processing being performed at the time of display is generally a mixture of normal processing and vibration cutting processing, and the ratio is, for example, 11:1. By displaying the time converted into the processing time of the processing being performed together with the processing time of vibration cutting, the display becomes easier to understand for the operator or maintenance person. Also, according to FIG. 10, the change unit 483 displays, for example, the life when the vibration conditions are not changed as "12 hours remaining" via the output control unit 44. Also, according to FIG. 10, the change unit 483 displays, for example, the life extended when the vibration conditions are changed as "+2 hours" in terms of vibration cutting time via the output control unit 44.

[0086] This allows the operator or maintenance person to recognize the necessity of changing the vibration conditions for vibration cutting, and to decide whether or not to change the vibration conditions for vibration cutting. Specifically, the operator or maintenance person can set the changed vibration conditions for the numerical control device 1 by pressing the button B1 for deciding to change the vibration cutting shown in FIG. 10. In addition, the operator or maintenance person can continue the vibration cutting process under the vibration conditions before the change without setting the changed vibration conditions for the numerical control device 1 by pressing the button B2 for deciding not to change the vibration conditions. In addition, the graph is displayed in parallel with a message prompting the change of the vibration conditions, so that the operator or maintenance person can intuitively grasp the situation. In addition, when the button B1 is pressed, the life of the brake device 711x can be extended.

[0087] The operator or maintenance person may change the vibration conditions for vibration cutting using vibration conditions determined from past experience such as machining conditions, instead of the vibration conditions calculated by the change unit 483. The change unit 483 may display, via the output control unit 44, for example, a graph showing the remaining life of the brake device 711x based on the vibration conditions determined by the operator or maintenance person. The change unit 483 may also display the change content of the vibration conditions via the output control unit 44. Specifically, the change unit 483 may display, for example, the vibration conditions before the change and the vibration conditions after the change on the output unit 3. The change unit 483 may also display a plurality of changed vibration conditions via the output control unit 44 to allow the operator or maintenance person to select one.

[0088] Further, the second threshold value Th2 is described as being set to one, but is not limited thereto. Two or more second threshold values ​​Th2 may be set. In this case, for example, in the graph shown in FIG. 6, two second threshold values ​​Th21=0.8 and Th22=1.0 are set, and the vibration conditions before the change are "vibration frequency per spindle rotation: 2.5 times", "spindle rotation speed: 4000 r / min", and "vibration frequency: 166.7 Hz" shown in FIG. 8. Then, for example, the change unit 483 displays on the output unit 3 via the output control unit 44 a screen that prompts the user to change the vibration conditions to "vibration frequency per spindle rotation: 2.5 times", "spindle rotation speed: 3333 r / min", and "vibration frequency: 142.9 Hz" when the estimated value of the backlash is equal to or greater than Th21 and less than Th22. Thereafter, if the estimated backlash value is greater than or equal to Th22 and less than Th1, the change unit 483 displays on the output unit 3 via the output control unit 44 a screen that prompts the user to change the vibration conditions to "number of vibrations per spindle rotation: 1.5 times," "spindle rotation speed: 3333 r / min," and "vibration frequency: 83.3 Hz."

[0089] At this time, the change unit 483 changes the vibration frequency from 166.7 Hz to 142.9 Hz in the first change, and changes the vibration frequency from 142.9 Hz to 83.3 Hz to further lower the frequency in the second change, so as to further extend the lifespan. By providing multiple thresholds in this way and providing an opportunity to further change the vibration conditions that have already been changed, it becomes possible to flexibly respond to cases where the operating policy, etc., changes midway, for example, when the replacement timing of the brake device is changed, etc.

[0090] In FIG. 5, when the estimation unit 482 determines that the estimated wear amount is not equal to or greater than the second threshold value (No in step S55), the process ends.

[0091] According to the above embodiment, the servo motor Ta The control calculation unit 4 of the numerical control device 1 that controls and causes the machine tool to perform vibration cutting has an estimation unit 482 that estimates, for example, deterioration of the brake device 711x based on the number of vibrations of the micro-vibrations associated with the vibration cutting.

[0092] As a result, for example, an operator or maintenance person can refer to the degradation estimation result estimated by the estimation unit 482 to know in advance when to replace the brake device 711x, and can take appropriate action before a malfunction or breakdown occurs.

[0093] Therefore, according to this embodiment, it is possible to grasp the deterioration caused by vibration cutting of the brake device equipped with the servo motor.

[0094] In addition, in Fig. 6, the threshold value Th1 is described as being about 1.2, and the threshold value Th2 is described as being about 1.0, but the present invention is not limited to this. For example, the progress of wear of the fastening hub varies depending on the machine configuration, specifically, the shape and size of the gears that constitute the fastening hub. For this reason, it is desirable to set the threshold value Th1 and the threshold value Th2 to be optimal depending on the machine configuration.

[0095] In addition, the graph shown in Fig. 6 has been described with an example of an average vibration frequency of 166.7 Hz, but is not limited to this. For example, similar control can be performed and similar effects can be achieved by using information showing the relationship between the execution time of vibration cutting and the amount of wear in the fastening hub, assuming a smaller vibration frequency, for example, an average of 30.3 Hz.

[0096] Variations. Although the embodiment of the present disclosure has been described above, various modifications and applications are possible when implementing the present disclosure. In the above embodiment, a case where the vibration conditions are changed based on the degradation estimation result estimated by the estimation unit 482, or the estimation result is output to an operator, etc. is described. In the modified example, a case where the vibration conditions are changed based on the measurement result obtained by actually performing a brake test in addition to the degradation estimation result estimated by the estimation unit 482, or the estimation result is output to an operator, etc. is described.

[0097] FIG. 11 is a diagram showing an example of the configuration of a numerical control device 1A according to a modified example. The numerical control device 1A has an input operation unit 2, an output unit 3, and a control calculation unit 4A. In addition, in Fig. 11, for example, a driving unit 7 which is a component of a machine tool is shown. Note that the driving unit 7 may be an element independent of the machine tool.

[0098] The control calculation unit 4A relating to the modified example has an input control unit 41, a data setting unit 42, a memory unit 43, an output control unit 44, an analysis processing unit 45, a control signal processing unit 46, a PLC circuit unit 47, an interpolation processing unit 48A, an acceleration / deceleration processing unit 49, an axis data input / output unit 50, and a test unit 51.

[0099] The input control unit 41, data setting unit 42, memory unit 43, output control unit 44, analysis processing unit 45, control signal processing unit 46, PLC circuit unit 47, acceleration / deceleration processing unit 49, and axis data input / output unit 50 are similar to those in the above embodiment, so their explanations will be omitted.

[0100] Interpolation processing unit 48A according to the modified example has a measurement unit 481, an estimation unit 482A, a change unit 483, a waveform generation unit 484, and a vibration movement amount generation unit 485. The measurement unit 481, the change unit 483, the waveform generation unit 484, and the vibration movement amount generation unit 485 are similar to those in the above embodiment, and therefore description thereof will be omitted.

[0101] An estimation unit 482A according to the modified example has a function of determining whether or not to perform a brake test based on the estimated amount of wear, in addition to the functions of the estimation unit 482 according to the above embodiment.

[0102] The test unit 51 executes a brake test. For example, when the test unit 51 receives a notification to execute a brake test from the estimation unit 482 of the interpolation processing unit 48, the test unit 51 executes the brake test. Specifically, the test unit 51 includes a test control unit 511 and a measurement unit 512.

[0103] The test control unit 511 controls the brake test. Specifically, when the test control unit 511 receives a notification from the estimation unit 482 that a brake test is to be performed, the test control unit 511 switches, for example, the brake of the brake device 711x of the X-axis servo motor 71x from OFF to ON. At this time, the test control unit 511 switches, for example, the brake of the brake device 711x from OFF to ON after confirming that a command to stop the rotation of the X-axis servo motor 71x has been issued.

[0104] The measurement unit 512 measures, for example, the backlash of a fastening hub provided in the brake device 711x. Specifically, the measurement unit 512 measures, for example, the magnitude of the backlash provided between the external gear 7111x and the internal gear 7112x. Since the backlash increases according to the execution time of the vibration cutting, by measuring this backlash, it becomes possible to recognize the degree of deterioration more accurately.

[0105] When the brake is switched from OFF to ON by the test control unit 511, the measurement unit 512 calculates the difference between the value of the FB counter in the FB control of the detector 72x at the time when the brake ON command is issued and the value of the FB counter at the time when the brake is turned ON and the rotation of the X-axis servo motor 71x is completely stopped, that is, at the time when the counter value stops changing. The FB counter value is transmitted to the measurement unit 512 from the detector 72x, for example, via the X-axis servo control unit 73x, the axis data input / output unit 50, the acceleration / deceleration processing unit 49, and the interpolation processing unit 48.

[0106] The measurement unit 512 divides the calculated difference value by the value of the FB counter per rotation to calculate the rotation angle of the fastening hub when the X-axis servo motor 71x is braked, as the backlash. The measurement unit 512 transmits the calculated backlash value to, for example, the estimation unit 482A.

[0107] The calculated backlash value may vary depending on the relative positional relationship between the external teeth 7119x of the external gear 7111x and the internal teeth 7120x of the internal gear 7112x at the time when the brake of the X-axis servo motor 71x is turned ON. For this reason, it is preferable that the test unit 51 executes several brake tests and calculates the average or maximum value of the backlash values ​​calculated for each test as a new backlash value. In addition, when the gear ratio between the gear on the motor shaft side and the gear on the brake device side that meshes with it is not 1:1, it is preferable to calculate the backlash taking the gear ratio into consideration.

[0108] The process executed by the numerical control device 1A configured as above will be described with reference to Fig. 12 and Fig. 6. Fig. 12 is a diagram showing an example of the process executed by the numerical control device 1A according to a modified example.

[0109] In FIG. 12, steps S121 and S122 are similar to steps S51 and S52 shown in FIG.

[0110] 12, when the estimation unit 482A estimates the amount of wear of the fastening hub included in the braking device 711x, the estimation unit 482A determines whether the estimated amount of wear is equal to or greater than a second threshold value (step S123). Here, the second threshold value is, for example, Th2 shown in FIG.

[0111] 12, when the estimation unit 482A determines that the estimated wear amount is equal to or greater than the second threshold value (Yes in step S123), it notifies the test unit 51, for example, that a brake test will be performed. Upon receiving the notification from the estimation unit 482A, the test unit 51 executes the brake test (step S124).

[0112] Specifically, when the test control unit 511 receives a notification from the estimation unit 482 that a brake test will be performed, it switches, for example, the brake of a brake device 711x of the X-axis servo motor 71x from an OFF state to an ON state.

[0113] When the brake is switched from OFF to ON by the test control unit 511, the measurement unit 512 calculates the difference between the value of the FB counter in the FB control of the detector 72x at the time when the brake is turned ON and the value of the FB counter at the time when the brake is turned ON and the rotation of the X-axis servo motor 71x stops. The measurement unit 512 divides the calculated difference value by the FB counter value per rotation to calculate the rotation angle of the fastening hub when the brake is applied to the X-axis servo motor 71x as the backlash. The measurement unit 512 transmits the calculated backlash value to, for example, the estimation unit 482A as a measurement value by the brake test.

[0114] 12, when the estimation unit 482A receives a measurement value from a brake test from the measurement unit 512, the estimation unit 482A determines whether the received measurement value from the brake test is equal to or greater than a first threshold value (step S125). Here, the first threshold value is, for example, Th1 shown in FIG.

[0115] 12, when the estimation unit 482A determines that the measurement value obtained by the brake test is equal to or greater than the first threshold value (Yes in step S125), the estimation unit 482A outputs a warning screen to the output unit 3 via the output control unit 44 (step S126). Note that the manner of output is the same as in the above embodiment.

[0116] When it is determined that the measurement value obtained by the brake test is not equal to or greater than the first threshold value (No in step S125), the estimation unit 482A determines whether the measurement value obtained by the brake test is equal to or greater than a second threshold value (step S127). Here, the second threshold value is, for example, Th2 shown in FIG.

[0117] 12, when the estimation unit 482A determines that the measurement value from the brake test is equal to or greater than the second threshold value (Yes in step S127), it notifies, for example, the change unit 483 to calculate the life extension condition of the brake device 711x. Upon receiving the notification to calculate the life extension condition, the change unit 483 calculates the life extension condition according to a predetermined condition (step S128). The method of calculating the life extension condition is the same as in the above embodiment.

[0118] In FIG. 12, step S129 is similar to step S57 shown in FIG.

[0119] 12, when the estimation unit 482A determines that the estimated wear amount is not equal to or greater than the second threshold (No in step S123), the process ends. Also, in FIG. 12, when the estimation unit 482A determines that the measured value by the brake test is not equal to or greater than the second threshold (No in step S127), the process ends.

[0120] According to the modified example, the control calculation unit 4A of the numerical control device 1A that controls a servo motor having a brake device and causes the machine tool to perform vibration cutting further includes, in addition to an estimation unit 482A that estimates, for example, the deterioration of the brake device 711x based on the execution time of the vibration cutting, a test unit 51 that performs a brake test on the brake device 711x. The control calculation unit 4A estimates the deterioration of the brake device based on the estimation result of the deterioration estimated based on the execution time of the vibration cutting and the result of the brake test. This makes it possible to estimate the deterioration of the brake device 711x with higher accuracy. In addition, since the brake test needs to be performed only when certain requirements are satisfied, it is possible to minimize the downtime of the machine due to the brake test.

[0121] Other embodiments. In the above embodiment, the estimation unit 482 estimates the deterioration of the brake device by estimating the amount of wear of a fastening hub provided in the brake device based on the execution time of vibration cutting, but is not limited to this. The estimation unit 482 may estimate the deterioration of the brake device by estimating the amount of wear of a friction plate provided in the brake device, for example, by estimating the amount of wear of a friction plate provided in the brake device.

[0122] Fig. 13 is a diagram for explaining the operation of a brake device according to another embodiment. Fig. 13 refers to an example of a schematic cross-sectional structure parallel to the X-axis direction of a brake device 911x corresponding to the brake device 711x shown in Fig. 3 in the above embodiment, and explains the operation when the brake is ON and when the brake is OFF. Note that Fig. 3 omits configurations other than those necessary for the explanation.

[0123] The brake device 911x shown in Fig. 13 is a brake device of a type that does not have a fastening hub, unlike the brake device of the type that has a fastening hub shown in Fig. 3. The brake device 911x includes a friction plate 9111x, a pressing plate 9112x, an electromagnetic coil 9113x, a spring 9114x, and a housing 9115x. The friction plate 9111x is fixed to the shaft 713x, and rotates together with the rotation of the shaft 713x.

[0124] In FIG. 13, when the brake is OFF, the electromagnetic coil 9113x is excited. That is, a current flows through the electromagnetic coil 9113x. At this time, an electromagnetic force larger than the elastic force of the spring 9114x is generated, and the pressing plate 9112x is attracted to the electromagnetic coil and moves to the opposite side of the motor main body 712x. As a result, the friction plate 9111x is disposed at a position away from the pressing plate 9112x. At this time, there is no friction between the friction plate 9111x and the pressing plate 9112x, and the rotation is not restricted. Therefore, the friction plate 9111x rotates together with the rotation of the shaft 713x.

[0125] 13, when the brake is ON, the current flowing through the electromagnetic coil 9113x is stopped, the electromagnetic force disappears, and the elastic force of the spring 9114x moves the pressing plate 9112x in a direction approaching the motor main body 712x. As a result, the friction plate 9111x comes into contact with the pressing plate 9112x, and the friction force stops the rotation of the friction plate 9111x. Therefore, the rotation of the shaft 713x to which the friction plate 9111x is fixed stops.

[0126] Here, in a numerical control device that causes a machine tool to perform vibration cutting, the friction plate 9111x included in the brake device 911x is a part that is more affected by wear caused by vibration cutting than by wear caused by braking operation, like the fastening hub of the brake device 711x of a type that has a fastening hub. For this reason, in a brake device 911x of a type that does not have a fastening hub, the deterioration of the brake device 911x may be estimated by estimating the amount of wear of the friction plate 9111x included in the brake device 911x based on the execution time of vibration cutting.

[0127] At this time, the estimation unit 482 uses information indicating the relationship between the execution time of vibration cutting using the X-axis servo motor 71x and the attraction time when the brake is OFF as information indicating the relationship between the execution time of vibration cutting using the X-axis servo motor 71x and the wear amount of the friction plate 9111x equipped with the brake device 911x. The attraction time when the brake is OFF is, for example, the time required for the pressing plate 9112x to be attracted to the electromagnetic coil 9113x shown in FIG. 13 after the current starts to flow through the electromagnetic coil 9113x when the brake is OFF. As the wear of the friction plate 9111x progresses, the distance between the electromagnetic coil 9113x and the friction plate 9111x increases. When the distance between the electromagnetic coil 9113x and the friction plate 9111x increases, the attraction current required when the brake is OFF increases. A predetermined time is required to increase the attraction current to a predetermined value, and since this predetermined value increases, the time from when the brake is OFF to when the rotation speed of the motor reaches the target value becomes longer. For this reason, in a braking device 911x of a type that does not have a fastening hub, deterioration of the friction plate 9111x becomes a bottleneck, and replacement of the braking device 911x becomes necessary.

[0128] The information indicating the relationship between the execution time of vibration cutting and the attraction current when the brake is OFF is, for example, information based on measured values ​​obtained in advance by performing a durability test on the vibration cutting time for a brake device having a similar mechanical configuration. The estimation unit 482 estimates the deterioration of the brake device 911x based on the information indicating the relationship between the execution time of vibration cutting and the attraction time of the friction plate when the brake is OFF. The estimation unit 482 estimates the deterioration of the brake device 911x by setting a first threshold value and a second threshold value, for example, as described in the above embodiment, for the information indicating the relationship between the execution time of vibration cutting and the attraction time when the brake is OFF. In addition, the estimation unit 482 may perform a brake test after making the estimation, as described in the modified example of the above embodiment.

[0129] In the above embodiment, the numerical control device 1 includes the input operation unit 2 and the output unit 3, but is not limited to this. Specifically, the input operation unit 2 or the output unit 3 may be externally attached to the numerical control device 1, and the numerical control device 1 may not include the input operation unit 2 or the output unit 3.

[0130] In the above embodiment, the numerical control device 1 performs vibration cutting by vibrating the tool, but this is not limited to the above. For example, the numerical control device 1 may perform vibration cutting by vibrating the workpiece.

[0131] Here, the hardware configuration of the control calculation unit 4 included in the numerical control device 1 and the control calculation unit 4A included in the numerical control device 1A will be described. Fig. 14 is a diagram showing an example of the hardware configuration of the control calculation unit according to the embodiment and the modified example. Note that the control calculation units 4 and 4A have the same hardware configuration, so the hardware configuration of the control calculation unit 4 will be described here.

[0132] The control calculation unit 4 can be realized by a control circuit 100 shown in Fig. 14, that is, a processor 101, and a memory 102. An example of the processor 101 is a CPU (Central Processing Unit, also called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration), etc. An example of the memory 102 is a RAM (Random Access Memory) or a ROM (Read Only Memory), etc.

[0133] The control calculation unit 4 is realized by the processor 101 reading and executing a program stored in the memory 102 for executing the operation of the control calculation unit 4. It can also be said that this program causes the computer to execute the procedure or method of the control calculation unit 4. The memory 102 is also used as a temporary memory when the processor 101 executes various processes.

[0134] The program executed by the processor 101 may be a computer program product having a computer-readable and non-transitory recording medium including a plurality of instructions executable by a computer to perform data processing. The program executed by the processor 101 causes the computer to execute the plurality of instructions to perform data processing.

[0135] The control and calculation unit 4 may be realized by dedicated hardware. The functions of the control and calculation unit 4 may be partially realized by dedicated hardware and partially realized by software or firmware.

[0136] Various embodiments and modifications of the present disclosure are possible without departing from the broad spirit and scope of the present disclosure. The above-described embodiments are for explaining the present disclosure and do not limit the scope of the present disclosure. In other words, the scope of the present disclosure is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the disclosure equivalent thereto are considered to be within the scope of the present disclosure. [Industrial Applicability]

[0137] According to the present disclosure, it is possible to provide a numerical control device capable of grasping deterioration caused by vibration cutting of a brake device that applies a brake to a servo motor. [Explanation of symbols]

[0138] 1, 1A numerical control device, 2 input operation unit, 3 output unit, 4, 4A control calculation unit, 41 input control unit, 42 data setting unit, 43 memory unit, 44 output control unit, 45 analysis processing unit, 46 control signal processing unit, 47 PLC circuit unit, 48, 48A interpolation processing unit, 481 measurement unit, 482, 482A estimation unit, 483 change unit, 484 waveform generation unit, 485 vibration movement amount generation unit, 49 acceleration / deceleration processing unit, 50 axis data input / output unit, 51 test unit, 511 test control unit, 512 measurement unit, 7 drive unit, 71x X-axis servo motor, 72x detector, 73x X-axis servo control unit, 711x brake device, 7111x external gear, 7112x internal gear, 7113x, 9111x friction plate.

Claims

1. A numerical control device that controls a servo motor and a brake device that brakes the servo motor, and causes a machine tool to perform vibration cutting, a numerical control device having an estimation unit that estimates deterioration of the brake device based on the number of vibrations of micro-vibrations caused by the vibration cutting.

2. A numerical control device that controls a servo motor and a brake device that brakes the servo motor, and causes a machine tool to perform vibration cutting, a numerical control device having an estimation unit that estimates deterioration of the brake device based on an execution time of the vibration cutting and a vibration frequency of the vibration cutting.

3. The numerical control device according to claim 1 or 2, wherein the estimation unit estimates the deterioration of the brake device by referring to deterioration progress information indicating a relationship between an execution time of the vibration cutting and a progress of deterioration of the brake device.

4. The numerical control device according to claim 1 , wherein the estimation unit estimates an amount of wear of a fastening hub provided in the brake device.

5. A test unit that performs a brake test on the brake device is further provided. The estimation unit estimates deterioration of the brake device based on the deterioration estimation result and the result of the brake test. The numerical control device according to claim 1 or 2.

6. 3. The numerical control device according to claim 1, further comprising a change unit that changes vibration conditions for the vibration cutting so as to slow down the progress of deterioration of the brake device based on a result of the estimation of the deterioration.

7. 7. The numerical control device according to claim 6, further comprising a change unit that changes vibration conditions for said vibration cutting so that a vibration frequency of said vibration cutting is reduced based on a result of said estimated deterioration.

8. The numerical control device according to claim 1 , further comprising an output control unit that outputs the degradation estimation result.

9. The output control unit outputs a life of the brake device based on the deterioration estimation result. The numerical control device according to claim 8.

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