Numerical control device

Abstract

A numerical control device disclosed herein that controls a servo motor (71x) and a braking device (7111x) for braking the servo motor to cause a machine tool to perform vibration cutting includes an estimation unit (482) for estimating deterioration of the braking device (711x) based on a number of cycles of microvibrations associated with the vibration cutting.

Description

Technical area

[0001] The present disclosure relates to a numerical control apparatus that controls vibration cutting. Technological background

[0002] A servo motor controlled by a numerical control device is usually equipped with a braking device, for example, to prevent a vertically movable feeder from falling when the power is turned off. The parts that make up the braking device wear out through repeated use of braking operations, etc., and the wear of these parts brings the braking device to the end of its service life. For this reason, it is important to anticipate the deterioration and service life of the braking device in advance and be well prepared for its malfunction and unexpected failure.

[0003] Various techniques have been proposed to detect deterioration of the braking device. For example, Patent Document 1 discloses a technique for monitoring the service life of an electromagnetic brake based on the total workload of the electromagnetic brake, which is obtained by calculating and summing the workload of the electromagnetic brake for each braking operation performed to cause the machine tool to perform an emergency stop. Prior art documentsPatent documents

[0004] Patent Document 1: Unexamined Japanese Patent Application, Publication No. 2006 - 155 199 Brief description of the inventionProblem to be solved by the invention

[0005] However, the effect of Patent Document 1 above is limited to monitoring deterioration caused by braking operation. For example, in a machine tool that performs vibration cutting, it is not possible to detect deterioration caused by vibration cutting in a mounting hub that is worn by vibration during vibration cutting, or in a braking device that includes a friction plate, etc., as parts.

[0006] The present disclosure has been made in view of the above circumstances and is intended to provide a numerical control apparatus capable of detecting deterioration caused by vibration cutting in a braking apparatus that brakes a servo motor. Means to solve the problems

[0007] The numerical control device according to the present disclosure controls a servo motor and a brake device for braking the servo motor to cause a machine tool to perform vibration cutting. To achieve the above objective, the numerical control device includes an estimation unit that estimates deterioration of the brake device based on the number of cycles of microvibrations associated with vibration cutting. Effect of the invention

[0008] According to the present disclosure, it is possible to provide a numerical control apparatus capable of detecting deterioration caused by vibration cutting in a braking apparatus that brakes a servo motor. Short description of the drawings Fig. 1 shows a configuration example of a numerical control device according to the embodiment. Fig. 2 shows an implementation example of a braking device according to the embodiment. Fig. 3 shows an operation of the braking device according to the embodiment. Fig. 4 shows an example of a structure of a fixing hub of the brake device according to the embodiment. Fig. 5 shows an example of a process performed by the numerical control apparatus according to the embodiment. Fig. 6 shows an example of information according to the embodiment, which shows the relationship between the execution time of vibration cutting and the wear value of the fixing hub provided in the braking device. Fig. 7 shows an example of a screen display output by the numerical control apparatus according to the embodiment. Fig. 8 shows operating conditions of a vibration cutting controller according to the embodiment. Fig. 9 schematically shows an example of vibration waveforms before and after changing the operating conditions for the vibration cutting control according to the embodiment. Fig. 10 shows another example of the screen display output by the numerical control apparatus according to the embodiment. Fig. 11 shows a configuration example of a numerical control device according to a modification. Fig. 12 shows an example of a process performed by the numerical control device according to the modification. Fig. 13 shows an operation of a braking device according to an alternative embodiment. Fig. 14 shows a hardware configuration example of a control calculation unit according to the embodiment and the modification. Embodiment for carrying out the invention

[0009] The following is a detailed description of a numerical control device according to the embodiment with reference to the drawings. Note that the present invention is not limited by the embodiments. Embodiment

[0010] Fig. Fig. 1 is a block diagram showing an example of a numerical control device 1 according to the embodiment. The numerical control (NC) device 1 shown in Fig. 1, for example, is a computer that performs the control of vibration cutting, which is a machining operation performed by vibrating a tool bit in a machine tool that performs vibration cutting. The numerical control device 1 includes an input operation unit 2, an output unit 3, and a control calculation unit 4. Also in Fig. 1, for example, is a drive unit 7, which is a component of the machine tool. It should be noted that the drive unit 7 may be a separate component from the machine tool.

[0011] The drive unit 7, connected to the control calculation unit 4, is a mechanism that drives the tool bit for machining a workpiece, which is the machining target of the machine tool, and / or the workpiece. In the present embodiment, for example, the drive unit 7 is a mechanism for machining a workpiece by rotating the workpiece and driving the tool bit in two directions: one parallel to the X-axis direction and the other parallel to the Z-axis direction. The X-axis direction is, for example, the vertical direction, in other words, the direction of gravity. The Z-axis direction is, for example, the horizontal direction. In the present embodiment, the central axis line of the workpiece is defined as the Z-axis, and the direction perpendicular to the Z-axis is defined as the X-axis.The axis directions are not limited to the above directions because they depend on the machine configuration.

[0012] The drive unit 7 includes 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 bit in the X-axis direction defined in 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 the command from the numerical control device 1 and position information and speed information detected by the detector 72x. Regarding feedback control, the term "feedback" may also be abbreviated as "FB" hereinafter. The X-axis servo control unit 73x realizes the movement of the tool bit in the X-axis direction by performing FB control of the X-axis servo motor 71x.The drive unit 7 outputs the position information detected by the detector 72x to the control calculation unit 4 as an FB vibration motion value on the X-axis.

[0013] The drive unit 7 also includes 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 bit in the Z-axis direction defined in 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 feedback control of the Z-axis servo motor 71z based on the 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 movement of the tool bit in the Z-axis direction by performing FB control of the Z-axis servo motor 71z. The drive unit 7 outputs position information detected by the detector 72z to the control calculation unit 4 as an FB vibration motion value on the Z-axis.

[0014] It should be noted that the machine tool may have one or more tool bit holders. For a machine tool with two or more tool holders, the drive unit 7 includes two or more sets of the X-axis servo motor 71x, the detector 72x, and the X-axis servo control unit 73x, as well as the Z-axis servo motor 71z, the detector 72z, and the Z-axis servo control unit 73z for each tool bit holder.

[0015] The drive unit 7 also includes a spindle motor 71s, a detector 72s, and a spindle control unit 73s. The spindle motor 71s rotates the spindle, which rotates the 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 the 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 rotational movement of the workpiece by performing FB control of the spindle motor 71s. Note that the rotation speed detected by the detector 72s corresponds to the rotation speed of the spindle motor 71s.

[0016] It should be noted that the machine tool may be one configured to machine two or more workpieces simultaneously. In the machine tool configured to process two or more workpieces simultaneously, the drive unit 7 includes two or more sets of the spindle motor 71s, the detector 72s, and the spindle control unit 73s. In this case, the machine tool is equipped with, for example, two or more tool bit holders.

[0017] The input operation unit 2 is the means by which information is input to the control calculation unit 4. The input operation unit 2 includes, for example, an input device such as a keyboard, a button, or a mouse. The input operation unit 2 accepts, for example, an input of a command, an input of a machining program number, and an input of a parameter related to vibration cutting from an operator to the numerical control device 1 and inputs them to the control calculation unit 4.

[0018] The output unit 3 is the means by which information from the control calculation unit 4 is output. The output unit 3 includes a display means such as a liquid crystal display device. The output unit 3 displays the information processed by the control calculation unit 4 on its display screen. Note that the present embodiment is assumed to include a display means as the output unit 3, but is not limited thereto. When the numerical control device 1 is connected to a network, the output unit 3 may be, for example, a display device or a display device of a computer connected to the network. The output unit 3 may also be an audio device such as a speaker.

[0019] The control 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, a programmable logic controller (PLC) circuit unit 47, an interpolation processing unit 48, an acceleration / deceleration processing unit 49, and an axis data input / output unit 50. Note that, in the present embodiment, the PLC circuit unit 47 is assumed to be disposed inside the control calculation unit 4, but the PLC circuit unit 47 may be disposed outside the control calculation unit 4.

[0020] The input control unit 41 accepts information input by 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 into the storage unit 43 via the input control unit 41 and the data setting unit 42.

[0021] The storage unit 43 includes a parameter storage area 431, a machining program storage area 432, a display data storage area 433, and a divided area 434.

[0022] Within the parameter storage area 431, the parameters used in the processing of the control calculation unit 4 are stored, in particular control parameters, servo parameters, tool bit data and parameters related to vibration cutting for operating the numerical control device 1.

[0023] The machining program storage area 432 stores a machining program including one or more blocks to be used to process the workpiece. Note that in the present embodiment, the machining program includes commands such as a move command for moving the tool bit and a rotate command for rotating the spindle.

[0024] The display data storage area 433 stores screen display data to be displayed by the output unit 3. The screen display data is data for displaying information by the output unit 3. The divided area 434 stores data that is temporarily used by the control calculation unit 4 to perform various processes. For example, the machining program number accepted by the input operation unit 2 is written into the divided area 434 of the storage unit 43 via the input control unit 41 and the data setting unit 42.

[0025] The output control unit 44 displays the screen display data stored in the display data storage area 433 of the storage unit 43 through the output unit 3.

[0026] 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 each other through the storage unit 43, through which information is written and read between them. When explaining 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 fact that such writing and reading are performed via the storage unit 43 may be omitted from time to time.

[0027] The analysis processing unit 45 is connected to the storage unit 43. The analysis processing unit 45 continuously refers to the machining program numbers written in the divided area 434 of the storage unit 43 to accept a selected machining program number stored in the divided area 434 from the divided area 434, and reads the selected machining program from the machining program storage area 432 to perform analysis processing of each block (each line) of the machining program. The analysis processing unit 45 analyzes codes such as an S code, which is a spindle motor rotation speed command, a G code, which is a shaft movement command, and an M code, which is a machine movement command.When the analysis processing of each line of the machining program is completed, the analysis processing unit 45 writes the analysis results of the S code, the G code, and the M code, etc., into the divided area 434 of the storage unit 43.

[0028] If the machining program includes an S code, the analysis processing unit 45 obtains the spindle rotation speed, which is the number of revolutions of the spindle, by analyzing the S code. The analysis processing unit 45 then writes the obtained spindle rotation speed to the shared area 434 of the storage unit 43.

[0029] If the machining program includes G-code, the analysis processing unit 45 obtains movement conditions, which are the feed conditions for the tool bit to move to the machining position, by analyzing the G-code. The movement conditions are specified by parameters, such as the X-axis and Z-axis speeds at which the tool bit holder is to be moved, and the X-axis and Z-axis positions to which the tool bit holder is to be moved. The analysis processing unit 45 then writes the obtained movement conditions to the shared area 434 of the storage unit 43.

[0030] If the machining program includes a G-code for vibration cutting, the analysis processing unit 45 obtains a vibration frequency, which is the frequency for vibrating the tool bit during vibration cutting, and vibration conditions, which include an amplitude for vibrating the tool bit during vibration cutting, by analyzing the G-code. The analysis processing unit 45 then writes the obtained vibration conditions to the divided area 434 of the storage unit 43.

[0031] The control signal processing unit 46, connected to the PLC circuit unit 47, receives signal information for routing, etc., from the PLC circuit unit 47 to operate the components of the machine tool. The control signal processing unit 46 writes the received signal information into the divided area 434 of the storage unit 43. The signal information is referenced by the interpolation processing unit 48 during processing of operations. When an auxiliary command is output to the divided area 434 by the analysis processing unit 45, the control signal processing unit 46 reads the auxiliary command from the divided area 434 and transmits it to the PLC circuit unit 47. The auxiliary command is a command that is different from the commands for moving a drive axis, which is a numerically controlled axis. The auxiliary command is, for example, an M code or a T code.

[0032] The interpolation processing unit 48 is connected to the storage unit 43 and the acceleration / deceleration processing unit 49. The interpolation processing unit 48 continuously refers to the divided area 434 of the storage unit 43. When the motion conditions and the vibration conditions are written into the divided area 434 by the analysis processing unit 45, the interpolation processing unit 48 reads the motion conditions and the vibration conditions to generate a commanded X-axis vibration motion value, which is a commanded vibration motion value in the X-axis direction, and a commanded Z-axis vibration motion value, which is a commanded vibration motion value in the Z-axis direction, using the read motion conditions and vibration conditions.The commanded X-axis vibration motion value and the commanded Z-axis vibration motion value are also collectively referred to simply as the commanded vibration motion values. The interpolation processing unit 48 writes the generated commanded vibration motion values ​​into the divided area 434 of the storage unit 43 and outputs them to the acceleration / deceleration processing unit 49. Upon receiving the FB vibration motion value from the acceleration / deceleration processing unit 49, the interpolation processing unit 48 writes the obtained FB vibration motion value into the divided area 434 of the storage unit 43.

[0033] 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 commanded vibration motion values ​​output from the interpolation processing unit 48 into the motion command per unit time, taking into account acceleration / deceleration according to a prespecified acceleration / deceleration pattern, and outputs the converted motion command to the axis data input / output unit 50. The acceleration / deceleration processing unit 49 also outputs the FB vibration motion value output from the axis data input / output unit 50 to the interpolation processing unit 48.

[0034] The axis data input / output unit 50 is connected to the acceleration / deceleration processing unit 49 and the drive unit 7. The axis data input / output unit 50 outputs the motion command per unit time output from the acceleration / deceleration processing unit 49 to the drive unit 7. The axis data input / output unit 50 also outputs the FB vibration motion value output from the drive unit 7 to the acceleration / deceleration processing unit 49.

[0035] Next, an implementation example of a braking device will be described. In the present embodiment, it is assumed that the X-axis servo motor 71x, which moves the tool bit in the X-axis direction, i.e., the vertical direction, includes a braking device. The braking device of the X-axis servo motor 71x can be either built-in or external to the X-axis servo motor 71x. The braking device can be provided in a servo motor different from the X-axis servo motor 71x. For example, a servo motor configured to control the tool bit to move in a direction including a vertical component is equipped with a braking device.

[0036] Fig. 2 shows an implementation example of the braking device according to the embodiment. According to Fig. 2, the X-axis servo motor 71x includes a brake device 711x, a motor body 712x, and a shaft 713x. Note that the detector 72x is provided on the X-axis servo motor 71x. The X-axis direction shown in Fig. 2, for example, represents the vertical direction.

[0037] According to Fig. 2, the X-axis servo motor 71x is connected to a feed mechanism 81x. The feed mechanism 81x includes a coupling 811x, a ball screw 812x, a slider 813x, and a ball screw support 814x. The coupling 811x functions as a connector between the X-axis servo motor 71x and the feed mechanism 81x. The ball screw 812x is arranged, for example, along the X-axis direction and can be rotated about the X-axis line via the coupling 811x by the rotation of the X-axis servo motor 71x. The slider 813x can be moved in the direction along the X-axis, for example, up and down along the vertical direction, by the rotation of the ball screw 812x.

[0038] When the machine tool suddenly stops due to an emergency or other reasons, the brake device 711x operates to stop the rotation of the motor body 712x. This stops the rotation of the ball screw 812x, which also stops the vertical movement of the slider 813x.

[0039] It should be noted that the braking device 711x may be included in the ball screw support 814x instead of on the motor body 712x side. In the above description, the X-axis was assumed to be the vertical direction. However, when using a machine tool in which processing is performed with the X-axis set at an angle to the vertical direction, the braking device may be included in the servo motor attached to the machine tool. When an axis other than the X-axis is set to include the vertical direction, the braking device may be included in the servo motor that controls the other axis. For example, when the Y-axis is set to include the vertical direction, the braking device may be specifically included in the servo motor that controls the Y-axis.

[0040] Next, operation of the braking device with a mounting hub is described. Fig. 3 shows the operation of the braking device according to the embodiment. Fig. 3 describes the operation of the braking device 711x when the brake is on and when the brake is off, with reference to an example of a schematic cross-sectional structure parallel to the X-axis direction of the braking device. In Fig. 3, configurations other than those necessary for the description are omitted.

[0041] The Fig. The brake device 711x shown in Figure 3 includes an externally toothed gear 7111x, an internally toothed gear 7112x, friction plates 7113x, a fixed plate 7114x, a pressing plate 7115x, a housing 7116x, an electromagnetic coil 7117x, and a spring 7118x. The externally toothed gear 7111x and the internally toothed gear 7112x are examples of the fixing hub claimed in the claims.

[0042] The externally toothed gear 7111x meshes with the internally toothed gear 7112x. The specific relationship between the externally toothed gear 7111x and the internally toothed gear 7112x is described below using Fig. 4 described. Fig. 4 shows an example of a structure of the fixing hub of the brake device according to the embodiment.

[0043] According to Fig. 4, for example, a through hole is provided in the externally toothed gear 7111x, and the shaft 713x is inserted into the through hole and fixed thereto. The externally toothed gear 7111x rotates around the axis of the shaft 713x in synchronization with the rotation of the shaft 713x.

[0044] The externally toothed wheel 7111x is provided with a plurality of external teeth 7119x along its circumference. The internally toothed wheel 7112x is provided with a plurality of internal teeth 7120x along its circumference. When the braking device 711x is used, the externally toothed wheel 7111x and the internally toothed wheel 7112x are arranged in a positional relationship such that the plurality of external teeth 7119x and the plurality of internal teeth 7120x arranged in Fig. 4. At this moment, the internal gear 7112x is movable in the X-axis direction relative to the external gear 7111x. When the brake is off, the internal gear 7112x rotates synchronously with the rotation of the external gear 7111x.

[0045] A certain amount of backlash is intentionally preset between the externally toothed gear 7111x and the internally toothed gear 7112x. Backlash is a deliberately provided gap where the gears mesh. An optimal backlash value is determined depending on, for example, the operation of the press plate 7115x, brake specifications, ease of assembly, etc. The unit of measurement for backlash is, for example, "arc minute." "Arc minute" is a unit of angular size representing one-sixtieth of "a degree" or "°." In the present embodiment, "°" is used as the unit of measurement representing backlash.

[0046] Referring again to Fig. 3, the friction plates 7113x are coupled to the internal gear 7112x. The friction plates 7113x rotate synchronously with the rotation of the internal gear 7112x. For example, the fixed plate 7114x functions to restrict the movement of the friction plates 7113x in the direction away from the side of the motor body 712x when the brake is switched from the off state to the on state.

[0047] In Fig. 3. When the brake is off, the electromagnetic coil 7117x is energized. In other words, a current flows in the electromagnetic coil 7117x. At this moment, an electromagnetic force greater than the elasticity of the spring 7118x occurs, attracting the pressing plate 7115x to the electromagnetic coil and moving it toward the side of the motor body 712x. This separates the friction plates 7113x from the fixed plate 7114x and the housing 7116x. Then, the friction plates 7113x have no friction with the fixed plate 7114x and the housing 7116x, so there is no restriction on their rotation. Therefore, the external gear 7111x can rotate synchronously with the rotation of the internal gear 7112x, and the friction plates 7113x can rotate synchronously with the shaft 713x.

[0048] In Fig. 3. When the brake is applied, the current flow in the electromagnetic coil 7117x stops, causing the electromagnetic force to disappear. The elasticity of the spring 7118x moves the pressure plate 7115x away from the motor body 712x. This causes the friction plates 7113x to touch and be sandwiched between the pressure plate 7115x and the fixed plate 7114x, restricting the rotation of the friction plates 7113x. Therefore, the rotation of the internal gear 7112x, coupled to the friction plates 7113x, is restricted, and the rotation of the external gear 7111x and the motor shaft 713x via the gears is stopped.

[0049] If the brake is on immediately after stopping the X-axis servo motor 71x in an emergency, etc., the Fig. 2, after falling by the amount of clearance provided between the external gear 7111x and the internal gear 712x due to the action of gravity. Therefore, in the event of an emergency stop, etc., the fall of the slider 813x can be stopped by the braking device 711x.

[0050] In normal machining other than vibration cutting, the X-axis movement for machining is performed in one direction. For example, each of the external teeth 7119x provided on the external gear 7111x, which is located in Fig. 4, therefore, a pair of adjacent teeth of the plurality of internal teeth 7120x provided on the internal gear 7112x meshes with each other, and is in contact with only one of the pair. In contrast, because micro-vibrations associated with vibration cutting are superimposed on the processing motion, during vibration cutting, each external tooth 7119x provided on the external gear 7111x repeatedly contacts both teeth of the pair of adjacent internal teeth 7120x that mesh with the external tooth 7119x on the internal gear 7112x, for example, in one cycle of the micro-vibrations associated with vibration cutting.Therefore, the multiple external teeth 7119x provided on the external gear 7111x and the multiple internal teeth 7120x provided on the internal gear 7112x wear out faster than in a case where only normal processing is performed, and the end of the service life of the braking device is reached sooner. If the servomotor continues to be used in a situation where the braking device has reached the end of its service life, for example, during an emergency stop, the slider 813x of the X-axis servomotor 71x may fall further than expected and collide with other mechanical structures, which may lead to failure. Therefore, the braking device must be replaced. In the numerical control device that enables the machine tool to perform vibration cutting, the mounting hub of the braking device 711x, i.e.The externally toothed gear 7111x and the internally toothed gear 7112x are more affected by wear caused by vibration cutting than by wear caused by braking. For example, micro-vibrations associated with vibration cutting are vibrations based on the vibration conditions for vibrating the tool bit during vibration cutting, which are transmitted to the braking device 711x while vibration cutting is being performed.

[0051] Referring again to Fig. 1, the interpolation processing unit 48 according to the present embodiment estimates the deterioration of the braking device based on the execution time of the vibration cutting. Specifically, the interpolation processing unit 48 includes a timing unit 481, an estimation unit 482, a changing unit 483, a waveform generation unit 484, and a vibration movement value generation unit 485.

[0052] The timing unit 481 measures the execution time of the vibration cutting. Specifically, the timing unit 481 stores, for example, an accumulated value of the duration during which the vibration cutting is processed in a braking device. The timing unit 481 also determines whether the accumulated value of the execution time of the vibration cutting is greater than or equal to a predetermined value.

[0053] The estimation unit 482 estimates the deterioration of the braking device 711x based on the number of cycles of micro-vibrations associated with vibration cutting. The estimation unit 482 estimates the deterioration of the braking device 711x based on, for example, the execution time of vibration cutting, which is measured by the timing unit 481, and the vibration frequency of vibration cutting. The vibration frequency of vibration cutting is, for example, a frequency set to generate the micro-vibrations during vibration cutting. The number of cycles of micro-vibrations associated with vibration cutting can be calculated from the execution time of vibration cutting and the vibration frequency of vibration cutting.The estimation unit 482 may also regard a value obtained by counting and accumulating the number of vibration cycles based on a vibration waveform, which is a basic waveform of vibrations generated by the waveform generation unit 484, as the number of cycles of the micro vibrations associated with the vibration cutting.

[0054] Specifically, the estimation unit 482 estimates the deterioration of the braking device 711x by referring to deterioration progression information indicating the relationship between the duration of vibration cutting and the progression of deterioration of the braking device. The deterioration progression information also includes information about the vibration frequency, which is a prerequisite for vibration cutting. The longer the duration of vibration cutting, the more the deterioration of the braking device progresses, and the deterioration progression information indicates the degree of deterioration.The deterioration progression information is, for example, information showing the relationship between the duration of vibration cutting and the wear value of the fixing hub included in the braking device. In other words, the longer the duration of vibration cutting, the greater the progression of wear of the fixing hub of the braking device. The wear value of the fixing hub is the amount of wear that occurs, for example, between the external gear 7111x and the internal gear 7112x. The wear value is obtained, for example, based on the clearance value between the external gear 7111x and the internal gear 7112x.

[0055] It should be noted that the information showing the relationship between the vibration cutting execution duration and the wear value of the brake device's mounting hub is based, for example, on measured values ​​obtained in advance by conducting a vibration cutting duration durability test for the brake device with the same or similar machine configuration as the 711x brake device. Specifically, the information is based on the measurement results of the brake device's mounting hub clearance obtained at multiple points in time during the vibration cutting execution duration. The brake device used for the durability test can be of the same type as the 711x brake device.

[0056] The vibration frequency as a precondition for measurement is, for example, 166.7 Hz on average. The average of 166.7 Hz is achieved, for example, by first setting various vibration frequencies for the test in the following manner: one at the vibration frequency of 166.7 Hz, at least one at the vibration frequencies lower than 166.7 Hz, and at least one at the vibration frequencies higher than 166.7 Hz, and further repeating the vibration cutting operation using the set vibration frequencies in steps such that the average vibration frequency of the vibration cutting performed in a predetermined duration becomes 166.7 Hz. Deviating from the above, the measurement may be performed with the vibration frequency, which is the precondition for measurement, set to a predetermined value, for example, 166.7 Hz.The vibration frequency, which is the precondition for measurement, does not need to be included in the deterioration progression information. In this case, the estimation unit 482 may refer to the deterioration progression information and the vibration frequency as the precondition for measurement, which is associated with the deterioration progression information.

[0057] The change unit 483 changes the vibration conditions of the vibration cutting based on the deterioration estimation result estimated by the estimation unit 482. Specifically, the change unit 483 changes, for example, the number of vibration cycles per spindle rotation (numerical value) and / or the spindle rotation speed (rpm) to extend the service life of the braking device 711x, in other words, to slow down the progression of deterioration of the braking device 711x. This changes the vibration frequency (Hz) of the micro-vibrations associated with the vibration cutting. Specifically, for example, the change unit 483 reduces the number of vibration cycles per spindle rotation (numerical value) and / or the spindle rotation speed (rpm) compared to before the change to reduce the vibration frequency (Hz) of the micro-vibrations associated with the vibration cutting.

[0058] The waveform generation unit 484 generates the vibration waveform as the basic vibration waveform based on the information obtained from the analysis processing unit 45. When the changing unit 483 changes the vibration conditions, the waveform generation unit 484 generates a vibration waveform based on the changed vibration conditions.

[0059] The vibration motion value generation unit 485 obtains, for example, a vibration motion value on the X-axis using the vibration waveform generated by the waveform generation unit 484 and a tool bit path. Specifically, the vibration motion value generation unit 485 generates the vibration motion value on the X-axis by calculating, for each vibration, a front vibration position obtained by adding an amplitude of the vibration waveform to a tool bit path position, and a rear vibration position obtained by subtracting the amplitude of the vibration waveform from the tool bit path position.

[0060] The vibration motion value generated by the vibration motion value 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 based on the vibration motion value sent from the vibration motion value generation unit 485, for example, by controlling the X-axis servo motor 71x.

[0061] The process performed by the numerical control device 1 configured as described above is carried out using Fig. 5 and Fig. 6 described. Fig. Figure 5 shows an example of the process performed by the numerical control device according to the embodiment. In the present embodiment, it is assumed that the vibration frequency of the vibration cutting before the change is 166.7 Hz. It is further assumed that the vibration frequency of the vibration cutting is 166.7 Hz on average as the precondition of the information indicating the relationship between the execution time of the vibration cutting and the wear value of the fixing hub of the brake device, which is referred to by the estimation unit 482.

[0062] According to Fig. 5. When the vibration cutting processing is started, the timing unit 481 starts measuring the execution time of the vibration cutting (step S51). Upon receiving a command to start cutting, the timing unit 481 starts measuring the execution time of the vibration cutting while the vibration cutting mode is on, for example, specifically. When the vibration cutting processing ends, the timing unit 481 stops measuring the execution time of the vibration cutting. The timing unit 481 stops timing the execution time of the vibration cutting, for example, specifically upon receiving a command to stop cutting while the vibration cutting mode is on.At this moment, the timer unit 481 adds the duration measured in step S1 to the accumulated duration of the execution duration measured in the past and stores the result as a new accumulated duration of the execution duration.

[0063] When the timing unit 481 finishes measuring the vibration cutting execution time, the estimation unit 482 estimates the deterioration of the braking device 711x based on the vibration cutting execution time measured by the timing unit 481 and the vibration cutting frequency (step S52). Specifically, the estimation unit 482 refers to, for example, the deterioration progress information to estimate the deterioration of the braking device 711x. For example, the estimation unit 482 estimates the deterioration of the braking device 711x based on the information showing the relationship between the vibration cutting execution time and the wear value of the braking device's mounting hub.

[0064] Fig. Fig. 6 shows an example of the information showing the relationship between the execution time of vibration cutting and the wear value of the fixing hub of the brake device according to the embodiment. Fig. 6, it is assumed that the vibration frequency as the precondition of the measurement is 166.7 Hz as an average. Fig. Figure 6 shows that the backlash, specifically the backlash between the externally toothed gear 7111x and the internally toothed gear 7112x, increases with increasing vibration cutting execution time. The estimation unit 482 estimates the wear value of the mounting hub of the brake device 711x by referring to the information showing the relationship between the vibration cutting execution time and the wear value of the mounting hub, and obtaining the backlash associated with the vibration cutting execution time measured by the timer unit 481. The graph in Fig. 6 shows the relationship between the vibration cutting execution time and the wear value of the brake device mounting hub in the case where the vibration cutting processing continues at an average frequency of 166.7 Hz, during which the vibration cutting execution time and the number of cycles of micro-vibrations associated with vibration cutting are approximately proportional. Therefore, the estimation unit 482 can use the information showing the relationship between the number of cycles of micro-vibrations associated with vibration cutting, which is calculated from the average vibration frequency and the vibration cutting execution time, and the wear value of the brake device mounting hub as the information for estimating the wear value of the brake device mounting hub 711x.

[0065] It is also suitable to measure the relationship between the execution time of vibration cutting and the clearance in advance for each of machine tool configurations, since the relationship depends on the conditions such as the shaft diameter of the servo motor, the ball screw diameter and the slider inertia.

[0066] In Fig. 5, after estimating the wear value of the mounting hub of the brake device 711x, the estimation unit 482 determines whether the estimated wear value is greater than or equal to a first threshold value (step S53). In Fig. 6, the first threshold is Th1. For example, the threshold Th1 is defined as the threshold at which the braking device must be replaced.

[0067] In Fig. 5, when it is determined that the estimated wear value is greater than or equal to the first threshold value (yes in step S53), the estimation unit 482 outputs, for example, a warning indication to the output unit 3 via the output control unit 44 (step S54).

[0068] Fig. Fig. 7 shows an example of a screen display output by the numerical control device according to the embodiment. Fig. 7, a message suggesting a replacement of the brake device 711x is displayed on the output unit 3. In Fig. 7, the estimation unit 482 displays, in particular via the output control unit 44 on the output unit 3, for example, the graph SL1 showing the relationship between the execution time of the vibration cutting performed with the included braking device 711x and the backlash, as well as the mark M1 showing the data point from the combination of the execution time of the vibration cutting when the message is output and the value of the backlash associated with the execution time of the vibration cutting.

[0069] In this case, the execution time of the vibration cutting, which is indicated by the mark M1 in Fig. 7 is greater than or equal to T1. The value of the clearance, which is indicated by the mark M1 in Fig. 7 is greater than or equal to the first threshold Th1. The mark M1 is not to be used in the Fig. 7. The marking M1 can be a circle, a rectangle, a triangle, or something else, as long as it is recognizable by the operator or maintenance personnel.

[0070] In Fig. 7, the estimation unit 482 also displays a message "It is time to replace the X-axis brake device. Replacement with a replacement brake device recommended." as a suggestion to replace the brake device 711x via the output control unit 44 on the output unit 3.

[0071] This allows the operator or maintenance personnel to recognize that the brake device replacement time has arrived and to replace the brake device on the target axis. The parallel display of the graph along with the message prompting replacement allows the operator or maintenance personnel to intuitively grasp the situation.

[0072] In Fig. 7, the estimation unit 482 displays both the graph and the message that encourages replacement, but only the message that encourages replacement may be displayed.

[0073] If the estimation unit 482 determines that the estimated wear value is neither greater than nor equal to the first threshold value (no in step S53), it determines whether the estimated wear value is not less than a second threshold value (step S55). In Fig. 6, the second threshold value is Th2, for example. This threshold value, Th2, is set as the threshold value that indicates, for example, when the vibration conditions should be changed to extend the service life of the braking device. Th2 is, for example, a value preset in the numerical control device during machine tool design. Th2 can be, for example, a value set by the operator according to the usage and processing status of the machine tool.

[0074] In Fig. 5, if the estimation unit 482 determines that the estimated wear value is greater than or equal to the second threshold (Yes in step S55), it instructs, for example, the changing unit 483 to calculate service life-extending conditions of the brake device 711x. Upon receiving the instruction to calculate the service life-extending conditions, the changing unit 483 calculates the service life-extending conditions according to predetermined conditions (step S56).

[0075] Fig. Figure 8 shows combinations of the vibration conditions according to the embodiment. As the parameters representing the operating conditions of the vibration cutting control, in other words, the vibration conditions, Fig. 8 the number of vibration cycles per spindle rotation (numerical value), the spindle rotation speed (rpm), and the vibration frequency (Hz). The vibration frequency is uniquely determined from the number of vibration cycles per spindle rotation and the spindle rotation speed. Therefore, the change unit 483 changes the number of vibration cycles per spindle rotation and / or the spindle rotation speed to extend the service life of the braking device 711x.

[0076] In the following, using Fig. 8 specific examples of calculating the service life extending conditions are described. As in Fig. As shown in Figure 8, it is assumed that the vibration conditions before the change are: number of vibration cycles per spindle rotation 2.5 times, spindle rotation speed 4000 r / min, and vibration frequency 166.7 Hz.

[0077] In Fig. 8, for example, the change unit 483 changes the spindle rotation speed from 4000 rpm to 3428 rpm without changing the number of vibration cycles per spindle rotation. This changes the vibration frequency from 166.7 Hz to 142.9 Hz. For example, the change unit 483 may accept an input of a desired extended service life and change the number of vibration cycles per spindle rotation and / or the spindle rotation speed by calculating backward from the input extended service life.

[0078] Fig. Fig. 9 is a schematic diagram showing an example of the vibration waveforms before and after the change in vibration conditions according to the embodiment. In Fig. 9, the vibration frequency before the change is 166.7 Hz and after the change is 142.9 Hz. In Fig. 9 In this case, the vibration cycle CT1 before the change is 6.0 ms and the vibration cycle CT2 after the change is 7.0 ms. Fig. 9 shows the vibration waveform C n for the nth cycle and the vibration waveform C n+1 for the (n+1)th cycle, which correspond to before and after the change in vibration conditions. Fig. Figure 9 shows air cutting regions S that occur between the nth cycle and the (n+1)th cycle, which function as the chip breaking regions generated during vibration cutting, before and after the change in vibration conditions. Each of the air cutting regions S is a region where, for example, no cutting action occurs between the tool bit in the path and the workpiece, and the tool bit merely runs freely, allowing the cutting chips generated up to that point to be separated into pieces.

[0079] As in Fig. As shown in Figure 9, it is possible to reduce the vibration frequency while generating the air cutting areas S before and after the change in the vibration conditions when the conditions are changed as described above. This makes it possible to calculate the vibration conditions for extending the service life of the braking device 711x while meeting the conditions that enable vibration cutting, that is, the conditions that enable the cutting operation while breaking the cutting chips. It should be noted that the Fig. 9 may be based on a vibration waveform according to a command value or a vibration waveform according to an FB value, as long as the vibration waveforms based on the measured values ​​satisfy the conditions that enable vibration cutting.

[0080] In Fig. 5, the change unit 483 calculates the service life-extending conditions in step S56 and changes the vibration conditions of the vibration cutting based on the calculated service life-extending conditions (step S57). The waveform generation unit 484 then generates the vibration waveform based on the changed vibration conditions, and the vibration cutting processing is executed based on the generated vibration waveform. Since the vibration frequency of the vibration cutting processing has been changed from 166.7 Hz to 142.9 Hz, Fig. 4, for example, the cycle at which each external tooth 7119x on the external gear 7111x contacts the pair of internal teeth 7120x meshing with the external tooth on the internal gear 7112x is extended, so that the number of contacts per unit time during vibration cutting can be reduced. As a specific result, the wear value of the fixing hub of the braking device 711x per unit time can be reduced during vibration cutting. In this case, the service life after the change can be expected to increase by approximately 1.17 times (166.7 Hz / 142.9 Hz). It is therefore possible to extend the service life of the braking device 711x.

[0081] The change unit 483 may be configured to present the calculated service life extending conditions to the operator or maintenance personnel. Fig. Fig. 10 shows another example of the screen display output by the numerical control device 1 according to the embodiment. Fig. 10, a message which encourages changing the vibration conditions in the X-axis servo motor 71x is displayed on the output unit 3.

[0082] In Fig. 10, the change unit 483 displays, in particular, on the output unit 3 via the output control unit 44, for example, the graph showing the relationship between the execution time of the vibration cutting and the backlash of the braking device 711x, as well as the mark M2 showing the combination of the execution time of the vibration cutting at the time of output of the message and the value of the backlash associated with the execution time of the vibration cutting. In Fig. 10, for example, the change unit 483 displays an estimation graph DL1, represented by a dashed line, via the output control unit 44. The estimation graph DL1 is a graph showing how much the service life can be extended if the changed vibration conditions are set at the time of outputting the message.

[0083] In this case, the duration of vibration cutting, which is indicated by the mark M2, is Fig. 10, greater than or equal to T2 and less than or equal to T1. The Fig. 10 The value of the clearance indicated by the mark M2 is greater than or equal to the second threshold Th2 and less than the first threshold Th1. The mark M2 is not limited to the value specified in Fig. 10. The marking M2 can be a circle, a rectangle, a triangle, or something else, as long as it is recognizable to the operator or maintenance personnel.

[0084] In Fig. 10, the change unit 483 also displays a message on the output unit 3 via the output control unit 44, "The replacement time of the X-axis brake device can be extended by approximately 2 hours relative to the duration of vibration cutting and approximately 24 hours relative to the duration of the current machining operation by changing the vibration conditions of the vibration cutting. Please make an earlier arrangement for replacing the brake device." as a suggestion to change the vibration conditions in the X-axis servo motor 71x. Furthermore, when such a message is displayed, the current machining operation is typically a combined machining operation of normal processing and vibration cutting processing with a ratio of, for example, 11:1.Converting the vibration cutting duration to the duration of the current machining operation and displaying the converted duration along with the vibration cutting duration can make the message more understandable for the operator or maintenance personnel. Fig. 10, the change unit 483 also displays, for example, the operating life expectancy in the event that the vibration conditions are not changed as a note of “12 hours remaining” via the output control unit 44. In Fig. 10, for example, the changing unit 483 also displays the extended portion of the service life expectancy, which can be achieved when the vibration conditions are changed, as a note of “+2 hours” via the output control unit 44.

[0085] This allows the operator or maintenance personnel to recognize the need to change the vibration conditions of the vibration cutting and to make a decision as to whether or not to change the vibration conditions of the vibration cutting. As a specific response, the operator or maintenance personnel can apply the changed vibration conditions to the numerical control device 1 by pressing the Fig. Press button B1 shown in Figure 10 to change the vibration cutting operation. The operator or maintenance personnel can choose not to set the changed vibration conditions for the numerical control device 1 and continue the vibration cutting process with the vibration conditions before the change by pressing button B2 to not change the vibration conditions. The parallel display of the graph along with the message prompting the change of the vibration conditions allows the operator or maintenance personnel to intuitively grasp the situation. Pressing button B1 extends the service life of the 711x braking device.

[0086] The operator or maintenance personnel can change the vibration conditions of the vibration cutting process using the vibration conditions determined from past experience of the processing conditions, instead of using the vibration conditions calculated by the change unit 483. The change unit 483 can display, on the output unit 3 via the output control unit 44, a graph showing, for example, the remaining service life of the braking device 711x based on the vibration conditions determined by the operator or maintenance personnel. The change unit 483 can also display the changes made to the vibration conditions via the output control unit 44. Specifically, the change unit 483 displays, for example, the vibration conditions before the change and the vibration conditions after the change on the output unit 3.The changing unit 483 can display various vibration conditions as options after changing via the output control unit 44 and allow the operator or maintenance personnel to select one.

[0087] The second threshold Th2 is not limited to a single setting described above. Two or more second thresholds Th2 may be set. For example, assume a case where two second thresholds Th21 = 0.8 and Th22 = 1.0 are set in the Fig. 6, and the vibration conditions before the change are “the number of vibration cycles per spindle rotation: 2.5”, “the spindle rotation speed: 4000 r / min” and “the vibration frequency: 166.7 Hz”, shown in Fig. 8. For example, if the estimated backlash value is greater than or equal to Th21 and less than Th22, the change unit 483 then displays a message on the output unit 3 via the output control unit 44, encouraging the change of the vibration conditions to "the number of vibration cycles per spindle rotation: 2.5," "the spindle rotation speed: 3333 rpm," and "the vibration frequency: 142.9 Hz." After a while, if the estimated backlash value is greater than or equal to Th22 and less than Th1, the change unit 483 then displays a message on the output unit 3 via the output control unit 44, encouraging the change of the vibration conditions to "the number of vibration cycles per spindle rotation: 1.5," "the spindle rotation speed: 3333 rpm," and "the vibration frequency: 83.3 Hz."

[0088] In this case, 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 83.2 Hz in the second change to further reduce the frequency, thereby further extending the service life. As described above, by setting various threshold values ​​and providing a way to further change the vibration conditions once changed, it is possible to flexibly respond to unexpected changes in operating rules, for example, when the replacement time of the braking device changes in the meantime.

[0089] In Fig. 5, when it is determined that the estimated wear value is not greater than or equal to the second threshold value (no in step S55), the estimation unit 482 ends the process.

[0090] According to the above embodiment, the control calculation unit 4 of the numerical control device 1, which causes the machine tool to perform the vibration cutting by controlling the servo motor and the brake device for braking the servo motor, includes, for example, the estimation unit 482 which estimates the deterioration of the brake device 711x based on the number of cycles of the micro-vibrations associated with the vibration cutting.

[0091] This allows the operator or maintenance personnel, for example, to know in advance the replacement time, etc. of the braking device 711x by referring to the estimation result of the deterioration estimated by the estimation unit 482, and therefore to take appropriate action before the occurrence of a failure or malfunction, etc.

[0092] According to the present embodiment, therefore, it is possible to detect the deterioration of the braking device of the servo motor caused by the vibration cutting.

[0093] In Fig. 6 describes that the values ​​of the thresholds Th1 and Th2 are approximately 1.2 and 1.0, respectively, but these are not limited to these values. For example, the rate of wear in the mounting hub depends on the machine configurations, particularly the size and shape, etc., of the gears that make up the mounting hub. Therefore, the thresholds Th1 and Th2 should be optimally set according to the machine configurations.

[0094] The vibration frequency, which is a prerequisite of the Fig. The graph shown in Figure 6 is described for the case of an average of 166.7 Hz as an example, but the vibration frequency is not limited to this. For example, the same control can be performed using information showing the relationship between the execution time of vibration cutting performed at a lower vibration frequency, for example, an average of 30.3 Hz, and the wear value of the mounting hub, and as a result, the same effect can be achieved. modification

[0095] The embodiment of the present disclosure has been described above. However, various modifications and applications are possible upon implementation of the present disclosure. In the above embodiment, the case in which the change in vibration conditions and the output of the estimation result to the operator, etc., are achieved based on the estimation result of deterioration estimated by the estimation unit 482 is described. In the modification, the case in which the change in vibration conditions and the output of the estimation result to the operator, etc., are achieved based on the measurement results obtained by actually performing a brake test, in addition to the estimation result of deterioration estimated by the estimation unit 482, is described.

[0096] Fig. Figure 11 shows a configuration example of a numerical control device 1A according to the modification. The numerical control device 1A includes the input operation unit 2, the output unit 3, and a control calculation unit 4A. Fig. 11, the drive unit 7 is shown, for example, as a component of the machine tool. The drive unit 7 may be a separate component from the machine tool.

[0097] The control calculation unit 4A according to the modification includes the input control unit 41, the data setting unit 42, the storage unit 43, the output control unit 44, the analysis processing unit 45, the control signal processing unit 46, the PLC circuit unit 47, an interpolation processing unit 48A, the acceleration / deceleration processing unit 49, the axis data input / output unit 50, and a test unit 51.

[0098] The input control unit 41, the data setting unit 42, the storage unit 43, the output control unit 44, the analysis processing unit 45, the control signal processing unit 46, the PLC circuit unit 47, the acceleration / deceleration processing unit 49, and the axis data input / output unit 50 are the same as those of the above-described embodiment and are therefore omitted from the following description.

[0099] The interpolation processing unit 48A according to the modification includes the timing unit 481, an estimation unit 482A, the changing unit 483, the waveform generating unit 484, and the vibration movement value generating unit 485. The timing unit 481, the changing unit 483, the waveform generating unit 484, and the vibration movement value generating unit 485 are the same as those of the above-described embodiment and are therefore omitted from the following description.

[0100] The estimation unit 482A according to the modification has, in addition to the functions of the estimation unit 482 according to the above-described embodiment, the function of determining whether or not to perform the brake test based on the estimated wear value.

[0101] The test unit 51 performs the braking test. The test unit 51 performs the braking test, for example, upon receiving an instruction to do so from the estimation unit 482 of the interpolation processing unit 48. In particular, the test unit 51 comprises a test control unit 511 and a measurement unit 512.

[0102] The test control unit 511 controls the brake test. Specifically, upon receiving the instruction to perform the brake test from the estimation unit 482, for example, the test control unit 511 switches the brake of the brake device 711x of the X-axis servo motor 71x from the off state to the on state. For example, the test control unit 511 switches the brake of the brake device 711x from the off state to the on state after verifying the output of the command to stop the rotation of the X-axis servo motor 71x.

[0103] For example, the measuring unit 512 measures the clearance of the mounting hub of the brake device 711x. Specifically, the measuring unit 512 measures the clearance between the external gear 7111x and the internal gear 7112x. Because the clearance increases proportionally with the duration of vibration cutting, measuring the clearance enables a more accurate detection of the degree of deterioration.

[0104] When the brake is switched from the off state to the on state by the test control unit 511, the measuring unit 512 calculates the difference between the value of an FB counter in the FB controller of the detector 72x at the moment an on command is issued to the brake and the value of the FB counter at the moment the rotation of the X-axis servo motor 71x completely stops due to the brake being turned on, that is, at the moment the counter value no longer changes. The value of the FB counter is transmitted from the detector 72x to the measuring unit 512 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, for example.

[0105] The measuring unit 512 calculates the rotation angle of the mounting hub when the X-axis servo motor 71x is decelerated as the backlash by dividing the calculated difference value by the value of the FB counter per rotation. The measuring unit 512 transmits the calculated backlash value to the estimation unit 482A, for example.

[0106] The backlash value to be calculated may vary depending on, for example, the relative positional relationship at the moment the brake is applied between the external teeth 7119x of the external gear 7111x and the internal teeth 7120x of the internal gear 7112x in the X-axis servo motor 71x. Therefore, it is appropriate for the test unit 51 to perform the braking tests multiple times to calculate the average or maximum value of the backlash values ​​obtained in each test as the new backlash value. If the gear ratio between the gear on the motor shaft side and the gear on the braking device side that meshes with the aforementioned gear is not 1:1, it is appropriate to calculate the backlash also taking the gear ratio into account.

[0107] The process performed by the numerical control device 1A configured as described above is carried out using Fig. 12 and Fig. 6 described. Fig. 12 shows an example of the process performed by the numerical control device 1A according to the modification.

[0108] In Fig. 12, step S121 and step S122 are equal to step S51 and step S52, which in Fig. 5 are shown.

[0109] In Fig. 12, the estimation unit 482A estimates the wear value of the mounting hub of the brake device 711x and determines whether the estimated wear value is greater than or equal to the second threshold value (step S123). Here, the second threshold value is, for example, Th2 shown in Fig. 6.

[0110] In Fig. 12, if the estimation unit 482A determines that the estimated wear value is greater than or equal to the second threshold (yes in step S123), it instructs, for example, the testing unit 51 to perform the brake test. Upon receiving the instruction from the estimation unit 482A, the testing unit 51 performs the brake test (step S124).

[0111] Specifically, upon receiving the instruction to perform the brake test from the estimation unit 482, the test control unit 511 switches, for example, the brake of the brake device 711x of the X-axis servo motor 71x from the off state to the on state.

[0112] When the brake is switched from off to on by the test control unit 511, the measuring unit 512 calculates the difference between the value of the FB counter in the FB controller of the detector 72x at the moment the brake is turned on and the value of the FB counter at the moment the rotation of the X-axis servomotor 71x is stopped by the turned-on brake. The measuring unit 512 calculates the rotation angle of the mounting hub when the X-axis servomotor 71x is braked as the backlash by dividing the calculated difference value by the value of the FB counter per rotation. The measuring unit 512 transmits the calculated backlash value to, for example, the estimation unit 482A as the measured value of the brake test.

[0113] In Fig. 12, upon receiving the measured value of the brake test from the measuring unit 512, the estimation unit 482A determines whether the received measured value of the brake test is greater than or equal to the first threshold value (step S125). Here, the first threshold value is, for example, Th1, shown in Fig. 6.

[0114] In Fig. 12, if it is determined that the measured value of the brake test is greater than or equal to the first threshold (Yes in step S150), the estimation unit 482A outputs, for example, the warning indication to the output unit 3 via the output control unit 44 (step S126). The type of output is the same as in the above-described embodiment.

[0115] If it is determined that the measured value of the brake test is not greater than or equal to the first threshold (no, step S125), the estimation unit 482A determines whether the measured value of the brake test is greater than or equal to the second threshold (step S127). Here, the second threshold is, for example, Th2 shown in Fig. 6.

[0116] In Fig. 12, if it is determined that the measured value of the brake test is greater than or equal to the second threshold (yes in step S127), the estimation unit 482A instructs, for example, the changing unit 483 to calculate the service life-extending conditions of the braking device 711x. Upon receiving the instruction to calculate the service life-extending conditions, the changing unit 483 calculates the service life-extending conditions according to predetermined conditions (step S128). The calculation method of the service life-extending conditions is the same as that of the above-described embodiment.

[0117] In Fig. 12, step S129 is the same as step S57 shown in Fig. 5.

[0118] In Fig. 12, if it is determined that the estimated wear value is not greater than or equal to the second threshold value (no in step S123), the estimation unit 482A ends the process. In Fig. 12, when it is determined that the measured value of the braking value is not greater than or equal to the second threshold value (no in step S127), the estimation unit 482A ends the process.

[0119] According to the modification, the control calculation unit 4A of the numerical control device 1A, which causes the machine tool to perform vibration cutting by controlling the servo motor with the braking device, further includes, for example, the test unit 51 that performs the braking test of the braking device 711x, in addition to the estimation unit 482A that estimates the deterioration of the braking device 711x based on the vibration cutting execution time. The control calculation unit 4A estimates the deterioration of the braking device based on the deterioration estimation result, which is estimated based on the vibration cutting execution time, and the braking test result. This enables a more accurate estimation of the deterioration of the braking device 711x.Because the brake test only needs to be performed when specified requirements are met, it is also possible to minimize machine downtime due to the brake test. Alternative embodiment

[0120] In the above embodiment, the estimation unit 482 estimates the deterioration of the brake device by estimating the wear value of the brake device's mounting hub based on the vibration cutting execution time, but is not limited to this. The component to be used as the deterioration indicator can be any component of the brake device as long as it deteriorates with the vibration cutting execution time and its deterioration can be detected. For example, the estimation unit 482 can estimate the deterioration of the brake device by estimating the wear value of the friction plates of the brake device.

[0121] Fig. Figure 13 shows the operation of the braking device according to the alternative embodiment. Fig. 13, the operation of the braking device when the brake is turned on and when the brake is turned off will be described with reference to an example of a schematic cross-sectional structure parallel to the X-axis direction of a braking device 911x which corresponds to the one shown in Fig. 3 shown braking device 711x in the embodiment described above. In Fig. 3 configurations are omitted which are different from those necessary for the description.

[0122] The Fig. 13 is a type of braking device without the fixing hub, as opposed to a type of braking device with the fixing hub, which is shown in Fig. 3. The braking device 911x includes a friction plate 9111x, a pressure 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 with the rotation of the shaft 713x.

[0123] In Fig. 13, when the brake is off, the electromagnetic coil 9113x is energized. In other words, a current flows in the electromagnetic coil 9113x. At this moment, an electromagnetic force greater than the elasticity of the spring 9114x occurs, attracting the pressure plate 9112x to the electromagnetic coil and moving it to the opposite side of the motor body 712x. This separates the friction plate 9111x from the pressure plate 9112x. Then, the friction plate 9111x has no friction with the pressure plate 9112x, so there is no restriction on its rotation. The friction plate 9111x therefore rotates with the rotation of the shaft 713x.

[0124] In Fig. 13. When the brake is applied, the current flow in the electromagnetic coil 9113x stops, causing the electromagnetic force to disappear. The elasticity of the spring 9114x moves the pressure plate 9112x closer to the motor body 712x. This brings the friction plate 9111x into contact with the pressure plate 9112x, and the rotation of the friction plate 9111x is restricted by the friction force. Therefore, the rotation of the shaft 713x with the friction plate 9111x fixed stops.

[0125] In the numerical control device that enables the machine tool to perform vibration cutting, the friction plate 9111x of the brake device 911x is a component that wears more during vibration cutting than during braking, similar to the fixing hub of the brake device 711x of a type of brake device with a fixing hub. Therefore, in the brake device 911x of a type of brake device without a fixing hub, the deterioration of the brake device 911x can be estimated by estimating the wear value of the friction plate 9111x of the brake device 911x based on the duration of vibration cutting.

[0126] In this case, the estimation unit 482 uses the information showing the relationship between the execution time of vibration cutting and a duty cycle in which the brake is turned off as the information showing the relationship between the execution time of vibration cutting using the X-axis servo motor 71x and the wear value of the friction plate 9111x of the brake device 911x. The duty cycle in which the brake is turned off is, for example, the time that elapses until the pressing plate 9112x is attracted to the electromagnetic coil 9113x after the current is turned off by turning off the brake in the electromagnetic coil 9113x shown in Fig. 13, begins to flow. As the friction plate 9111x wears, the distance between the electromagnetic coil 9113x and the friction plate 9111x increases. As the distance between the electromagnetic coil 9113x and the friction plate 9111x increases, the inrush current required when the brake is turned off increases. Then, a specific amount of time is required for the inrush current to rise to a certain value. However, as the certain value becomes larger, the time from the time the brake-off command is issued to the time the motor rotation speed reaches a target value becomes longer. Therefore, in the brake device 911x of a type of brake device without the fixing hub, the deterioration of the friction plate 9111x becomes a bottleneck in operation, necessitating the replacement of the brake device 911x.

[0127] The information indicating the relationship between the vibration cutting execution time and the inrush current while the brake is off is information based, for example, on the measured values ​​obtained in advance by conducting a vibration cutting duration durability test on a brake device of the same machine configuration. The estimation unit 482 estimates the deterioration of the brake device 911x based on the information indicating the relationship between the vibration cutting execution time and the friction plate duty cycle when the brake is off.The estimation unit 482 estimates the deterioration of the braking device 911x, for example, by setting the first threshold and the second threshold in the same manner as described in the above embodiment regarding the information indicating the relationship between the execution time of vibration cutting and the duty cycle when the brake is off. The estimation unit 482 may be configured to perform the braking test after the estimation is made, in the same manner as described in the modification of the above embodiment.

[0128] In the above embodiment, the numerical control device 1 is described as including the input operation unit 2 and the output unit 3, but the configuration is not limited to this. Specifically, the input operation unit 2 or the output unit 3 may be externally mounted to the numerical control device 1 to configure the numerical control device 1 without the input operation unit 2 or the output unit 3.

[0129] In the above embodiment, it was described that the numerical control device 1 performs vibration cutting by vibrating the tool bit, but the vibrating side is not limited to the tool bit. For example, the numerical control device 1 may vibrate the workpiece to perform vibration cutting.

[0130] Now, hardware configurations of the control calculation unit 4 of the numerical control device 1 and the control calculation unit 4A of the numerical control device 1A will be described. Fig. 14 shows a hardware configuration example of the control calculation unit according to the embodiment and the modification. Since the control calculation units 4 and 4A have the same hardware configuration, the hardware configuration of the control calculation unit 4 will be discussed here.

[0131] The control calculation unit 4 can be implemented with a control circuit 100, ie using a processor 101 and a memory 102, shown in Fig.14. An example of processor 101 is a CPU (alternatively referred to as a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, and digital signal processor (DSP)) and a highly integrated system. An example of memory 102 is random access memory (RAM) and read-only memory (ROM).

[0132] The control calculation unit 4 is implemented by the processor 101, which reads and executes a program stored in the memory 102 to perform the operation of the control calculation unit 4. The program can be said to be a recipe for causing a computer to perform the procedures or methods of the control calculation unit 4. The memory 102 is also used as a temporary storage when the processor 101 performs various processes.

[0133] The program to be executed by processor 101 may be a computer program product provided as a computer-readable and non-transitory storage medium containing a plurality of instructions executable by the computer to perform the data processing. When processor 101 executes the program, the computer performs the data processing through the plurality of instructions.

[0134] Alternatively, the control calculation unit 4 may be implemented by dedicated hardware. The functions of the control calculation unit 4 may be implemented partially by dedicated hardware and partially by software or firmware.

[0135] The present disclosure allows for various embodiments and modifications without departing from the broader spirit and scope of the present disclosure. The above embodiments are provided to illustrate the present disclosure and are not intended to limit the scope of the present disclosure. In other words, the scope of the present disclosure is shown by the scope of the claims, not by the embodiments. This means that the various modifications made within the scope of the claims and within the meaning of the disclosure equivalent to the claims are to be regarded as within the scope of the present disclosure. Industrial availability

[0136] According to the present disclosure, it is possible to provide a numerical control apparatus capable of detecting the deterioration of the braking device that brakes the servo motor caused by vibration cutting. List of reference symbols 1, 1A Numerical Control Device 2 Input control unit 3 Output unit 4, 4A Control calculation unit 41 Input control unit 42 Data setting unit 43 storage unit 44 Output control unit 45 Analysis processing unit 46 Control signal processing unit 47 PLC circuit unit 48, 48A Interpolation processing unit 481 timing unit 482, 482A estimating unit 483 Change Unit 484 Waveform generation unit 485 Vibration motion value generation unit 49 Acceleration / deceleration processing unit 50 axis data input / output unit 51 test units 511 Test control unit 512 measuring unit 7 Drive unit 71x X-axis servo motor 72x detector 73x X-axis servo control unit 711x braking device 7111x externally toothed wheel 7112x internally toothed wheel 7113x, 9111x friction plate 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 2006 - 155 199

[0004]

Claims

[1] A numerical control device that controls a servo motor and a brake device for braking the servo motor to cause a machine tool to perform vibration cutting, the numerical control device comprising: an estimation unit that estimates deterioration of the braking device based on a number of cycles of micro-vibrations associated with vibration cutting. [2] A numerical control device that controls a servo motor and a brake device for braking the servo motor to cause a machine tool to perform vibration cutting, the numerical control device comprising: an estimation unit that estimates deterioration of the braking device based on an execution time of the vibration cutting and a vibration frequency of the vibration cutting. [3] The numerical control apparatus according to claim 1 or 2, wherein the estimation unit estimates the deterioration of the braking device by referring to deterioration progress information indicating a relationship between the execution time of the vibration cutting and a progress of the deterioration of the braking device. [4] The numerical control apparatus according to any one of claims 1 to 3, wherein the estimation unit estimates a wear value of a fixing hub provided in the braking apparatus. [5] The numerical control apparatus according to any one of claims 1 to 3, wherein the estimation unit estimates a wear value of a friction plate provided in the brake apparatus. [6] A numerical control apparatus according to any one of claims 1 to 5, further comprising: a test unit for performing a brake test of the braking device, wherein the estimation unit estimates the deterioration of the braking device based on the estimation result of the deterioration and a result of the braking test. [7] The numerical control apparatus according to any one of claims 1 to 6, further comprising a changing unit that changes vibration conditions of the vibration cutting based on the estimation result of the deterioration to slow down the progress of the deterioration of the braking apparatus. [8] The numerical control apparatus according to claim 7, further comprising a changing unit that changes vibration conditions of the vibration cutting based on the estimation result of the deterioration to reduce the vibration frequency of the vibration cutting. [9] The numerical control apparatus according to any one of claims 1 to 8, further comprising an output control unit that outputs the estimation result of the deterioration. [10] The numerical control apparatus according to claim 9, wherein the output control unit outputs a service life of the braking apparatus based on the estimation result of the deterioration.

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