Numerical control device

Abstract

Numerical control device (1, 1A) which controls a servo motor (71x) to cause a machine tool to perform vibratory cutting, wherein the numerical control device (1, 1A) comprises: an estimation unit (482, 482A) which estimates a deterioration of a braking device (711x) for braking the servo motor (71x) based on a number of cycles of micro-vibrations associated with vibratory cutting.

Description

Technical area

[0001] The present disclosure relates to a numerical control device which controls vibratory cutting. Technological background

[0002] A servomotor controlled by a numerical control device is typically equipped with a braking device to prevent, for example, a vertically moving feeder from falling when the power is switched off. The components of the braking device wear down through repeated use of the braking mechanism, and this wear eventually brings the braking device to the end of its service life. Therefore, it is important to detect the deterioration and remaining service life of the braking device in advance and to be well prepared for its malfunction and unexpected failure. Various techniques have been proposed for detecting the 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 a workload of the electromagnetic brake and summing it for each braking operation that is carried out to cause the machine tool to perform an emergency stop.

[0003] Patent document 2 discloses a numerical control system comprising: an image processing unit that divides the curve of an oscillation motion command value specified by a vibration cutting command and the curve of an actual position detected by detectors into sections, each corresponding to a unit of time, wherein the image processing unit displays on a display unit the curve of an nth oscillation command, which is the nth curve of the oscillation motion command value, the curve of an (n+1)th oscillation command, which is the (n+1)th curve of the oscillation motion command value, the curve of an nth actual position, which is the nth curve of the actual position, and the curve of an (n+1)th actual position, which is the (n+1)th curve of the actual position.which are superimposed along a time axis, where n is a natural number. State-of-the-art documents, patent documents Patent document 1: JP 2006 - 155 199 A Patent document 2: DE 11 2019 007 493 T5 Brief description of the invention Problem to be solved by the invention

[0004] However, the effect of patent document 1 above is limited to monitoring the deterioration caused by braking operation. For example, in a machine tool performing vibratory cutting, it is not possible to detect the deterioration caused by the vibratory cutting in a mounting hub, which is worn by the vibration of the vibratory cutting process, or in a braking device that includes a friction plate, etc., as components.

[0005] The present disclosure was made in view of the above circumstances and is intended to provide a numerical control device which is designed to detect the deterioration caused by vibration cutting in a braking device which brakes a servo motor. Means of solving the problems

[0006] The problem is solved by the invention according to the numerical control devices of the independent claims. Advantageous embodiments of the invention are defined in the dependent claims. Effect of the invention

[0007] According to the present disclosure, it is possible to provide a numerical control device which is designed to detect the deterioration caused by vibration cutting in a braking device which brakes a servo motor. Brief description of the drawings Fig. Figure 1 shows a configuration example of a numerical control device according to the embodiment. Fig. Figure 2 shows an implementation example of a braking device according to the embodiment. Fig. Figure 3 shows an operation of the brake device according to the embodiment. Fig. Figure 4 shows an example of a structure of a mounting hub of the brake device according to the embodiment. Fig. Figure 5 shows an example of a process that is carried out by the numerical control device according to the embodiment. Fig. Figure 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 mounting hub provided in the braking device. Fig. Figure 7 shows an example of a screen display output by the numeric control device according to the embodiment. Fig. Figure 8 shows operating conditions of a vibration cutting control according to the embodiment. Fig. Figure 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. Figure 10 shows another example of the screen display output by the numeric control device according to the embodiment. Fig. Figure 11 shows a configuration example of a numerical control device according to a modification. Fig. Figure 12 shows an example of a process that is carried out by the Numerical Control Device according to the modification. Fig. Figure 13 shows the operation of a braking device according to an alternative embodiment. Fig. Figure 14 shows a hardware configuration example of a control computing unit according to the embodiment and the modification. embodiment for carrying out the invention

[0008] The following is a detailed description of a numerical control device according to the embodiment shown in the drawings. It should be noted that the present invention is not limited by these embodiments. embodiment

[0009] Fig. Figure 1 is a block diagram showing an example of a numerical control device 1 according to the embodiment. The numerical control (NC) device 1, which is in Fig. Figure 1 shows, for example, a computer that controls vibratory cutting, a machining operation performed by vibrating a tool bit in a machine tool that carries out the vibratory cutting. The numerical control device 1 comprises an input operating unit 2, an output unit 3, and a control calculation unit 4. Also in Fig. Figure 1 shows, for example, a drive unit 7, which is a component of the machine tool. It should be noted that the drive unit 7 can be a separate component from the machine tool.

[0010] The drive unit 7, connected to the control unit 4, is a mechanism that drives the tool bit for machining a workpiece, which is the target of the machining operation by the machine tool, and / or the workpiece itself. In the present embodiment, the drive unit 7 is, for example, 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 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 directions above because they depend on the machine configuration.

[0011] The drive unit 7 comprises 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, which is 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 and speed information detected by the detector 72x. In the context of feedback control, the term "feedback" can also be abbreviated as FB in the following. The X-axis servo control unit 73x realizes the movement of the tool bit in the X-axis direction by performing an FB control of the X-axis servo motor 71x.The drive unit 7 outputs the position information, which is detected by the detector 72x, to the control calculation unit 4 as an FB vibration motion value on the X-axis.

[0012] 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, which is 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 the feedback control of the Z-axis servo motor 71z based on the command from the numerical control device 1 and position 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 the function block (FB) control of the Z-axis servo motor 71z. The drive unit 7 outputs position information, which is detected by the detector 72z, to the control calculation unit 4 as an FB vibration motion value on the Z-axis.

[0013] It should be noted that the machine tool can have one or more tool bit holders. For a machine tool with two or more tool holders, the drive unit 7 comprises two or more sets of the X-axis servo motor 71x, the detector 72x, and the X-axis servo control unit 73x per tool bit holder, as well as the Z-axis servo motor 71z, the detector 72z, and the Z-axis servo control unit 73z.

[0014] 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 turns the workpiece. The detector 72s detects the position and rotational speed of the spindle motor 71s. The spindle control unit 73s performs the FB control of the spindle motor 71s based on the command from the numerical control device 1 and position and speed information detected by the detector 72s. The spindle control unit 73s controls the rotational movement of the workpiece by performing the FB control of the spindle motor 71s. It should be noted that the rotational speed detected by the detector 72s corresponds to the rotational speed of the spindle motor 71s.

[0015] It should be noted that the machine tool can be one designed to machine two or more workpieces simultaneously. In a machine tool designed to process two or more workpieces simultaneously, the drive unit 7 comprises two or more sets consisting of the spindle motor 71s, the detector 72s, and the spindle control unit 73s. In this case, the machine tool is equipped, for example, with two or more tool bit holders.

[0016] The input control unit 2 is the means by which information is entered for the control processing unit 4. The input control unit 2 includes, for example, an input device such as a keyboard, a button, or a mouse. The input control unit 2 accepts, for example, an input of a command, an input of a machine processing program number, and an input of a parameter relating to vibratory cutting from an operator to the numerical control device 1 and enters them into the control processing unit 4.

[0017] The output unit 3 is the means by which information from the control processing unit 4 is output. The output unit 3 includes a display device, such as a liquid crystal display. The output unit 3 displays the information processed by the control processing unit 4 on its display screen. It should be noted that the present embodiment is assumed to include a display device as the output unit 3, but is not limited to this. If the numeric control device 1 is connected to a network, the output unit 3 could, for example, be a display device or a display device of a computer connected to the network. The output unit 3 could also be an audio device, such as a loudspeaker.

[0018] The control processing unit 4 comprises 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) switching unit 47, an interpolation processing unit 48, an acceleration / deceleration processing unit 49, and an axis data input / output unit 50. It should be noted that in the present embodiment, the PLC switching unit 47 is assumed to be located within the control processing unit 4; however, the PLC switching unit 47 can also be located outside the control processing unit 4.

[0019] The input control unit 41 receives information entered by the input operating unit 2. The data setting unit 42 stores the information received by the input control unit 41 in the memory unit 43. This means that the entered information, accepted by the input operating unit 2, is written to the memory unit 43 via the input control unit 41 and the data setting unit 42.

[0020] The storage unit 43 comprises a parameter storage area 431, a machine processing program storage area 432, a display data storage area 433 and a shared area 434.

[0021] Within the parameter memory 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 relating to vibration cutting for operating the numerical control device 1.

[0022] The machine machining program memory area 432 stores a machine machining program comprising one or more blocks used for processing the workpiece. It should be noted that in the present embodiment, the machine machining program includes commands such as a movement command to move the tool bit and a rotation command to rotate the spindle.

[0023] Display data storage area 433 stores screen display data to be shown by output unit 3. This screen display data is used by output unit 3 to display information. Shared area 434 stores data that is temporarily used by control unit 4 to perform various processes. For example, the machine processing program number received by input unit 2 is written to shared area 434 of storage unit 43 via input control unit 41 and data setting unit 42.

[0024] The output control unit 44 displays the screen display data, which is stored in the display data memory area 433 of the memory unit 43, through the output unit 3.

[0025] In the control processing unit 4, the analysis processing unit 45, the control signal processing unit 46, and the interpolation processing unit 48 are interconnected by the storage unit 43, through which information is written to and read from these units. 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 fact that such writing and reading is performed via the storage unit 43 may occasionally be omitted.

[0026] The analysis processing unit 45 is connected to the storage unit 43. The analysis processing unit 45 continuously references the machine processing program numbers written to the shared area 434 of the storage unit 43 to retrieve a selected machine processing program number stored in shared area 434. It then reads the selected machine processing program from the machine processing program memory area 432 to perform analysis processing of each block (each line) of the machine processing program. The analysis processing unit 45 analyzes codes such as an S-code, which is an instruction for the rotational speed of the spindle motor; a G-code, which is an instruction for shaft movement; and an M-code, which is an instruction for machine motion.When the analysis processing of each line of the machine processing program is completed, the analysis processing unit 45 writes the analysis results of the S-code, G-code and M-code, etc. to the shared area 434 of the memory unit 43.

[0027] If the machine program includes an S-code, the analysis processing unit 45 obtains the spindle rotational speed, which is the number of spindle revolutions, by analyzing the S-code. The analysis processing unit 45 then writes the obtained spindle rotational speed to the shared area 434 of the storage unit 43.

[0028] If the machining program includes G-code, the analysis processing unit 45 obtains motion conditions, which are the feed conditions for the tool bit to move to the machining position, by analyzing the G-code. The motion conditions are specified by parameters, for example, 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 motion conditions to the shared area 434 of the memory unit 43.

[0029] If the machining program includes a G-code for vibratory cutting, the analysis processing unit 45 obtains a vibration frequency, which is the frequency for vibrating the tool bit during vibratory cutting, and vibration conditions, which include an amplitude for vibrating the tool bit during vibratory cutting, by analyzing the G-code. The analysis processing unit 45 then writes the obtained vibration conditions to the shared area 434 of the memory unit 43.

[0030] The control signal processing unit 46, connected to the PLC switching unit 47, receives signal information from the PLC switching unit 47 for forwarding, etc., to operate the machine tool components. The control signal processing unit 46 writes the received signal information to the shared area 434 of the memory unit 43. The interpolation processing unit 48 refers to this signal information during the processing of operations. When the analysis processing unit 45 outputs an auxiliary command to the shared area 434, the control signal processing unit 46 reads the auxiliary command from the shared area 434 and transmits it to the PLC switching unit 47. The auxiliary command is a command that differs 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.

[0031] 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 references the shared area 434 of the storage unit 43. When the motion conditions and vibration conditions are written to the shared area 434 by the analysis processing unit 45, the interpolation processing unit 48 reads the motion conditions and 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 ​​to shared area 434 of memory 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 received FB vibration motion value to shared area 434 of memory unit 43.

[0032] 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 by the interpolation processing unit 48 into the motion command per unit of time, taking into account acceleration / deceleration according to a pre-specified 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 by the axis data input / output unit 50 to the interpolation processing unit 48.

[0033] The axis data input / output unit 50 is connected to the acceleration / braking processing unit 49 and the drive unit 7. The axis data input / output unit 50 outputs the motion command per unit of time, which is issued by the acceleration / braking processing unit 49, to the drive unit 7. The axis data input / output unit 50 also outputs the FB vibration motion value, which is issued by the drive unit 7, to the acceleration / braking processing unit 49.

[0034] Next, an implementation example of a braking device is described. In the present embodiment, it is assumed that the X-axis servomotor 71x, which moves the tool bit in the X-axis direction, i.e., in the vertical direction, includes a braking device. The braking device of the X-axis servomotor 71x can be either integrated or external to the X-axis servomotor 71x. The braking device can be provided in a servomotor that is different from the X-axis servomotor 71x. For example, a servomotor configured to control the tool bit to move it in a direction that includes a vertical component is equipped with a braking device.

[0035] Fig. Figure 2 shows an implementation example of the braking device according to the embodiment. Fig. 2. The X-axis servomotor 71x comprises a brake device 711x, a motor body 712x, and a shaft 713x. It should be noted that the detector 72x is provided on the X-axis servomotor 71x. The X-axis direction, which is described in Fig. The line 2 shown, for example, represents the vertical direction.

[0036] According to Fig. In Figure 2, the X-axis servomotor 71x is connected to a feed mechanism 81x. The feed mechanism 81x comprises a coupling 811x, a ball screw 812x, a slider 813x, and a ball screw carrier 814x. The coupling 811x acts as a connector between the X-axis servomotor 71x and the feed mechanism 81x. The ball screw 812x, for example, is arranged along the X-axis and can be rotated around the X-axis via the coupling 811x by the rotation of the X-axis servomotor 71x. The slider 813x can be moved in the direction along the X-axis, e.g., up and down along the vertical direction, by the rotation of the ball screw 812x.

[0037] In the event of a sudden stop of the machine tool due to an emergency or other reason, the braking device 711x activates to stop the rotation of the motor body 712x. This stops the rotation of the ball screw drive 812x, which also stops the vertical movement of the slider 813x.

[0038] It should be noted that the braking device 711x may be contained within the ball screw carrier 814x instead of on the motor body 712x. In the description above, it was assumed that the X-axis is the vertical direction. However, if a machine tool is used in which the processing is performed with the X-axis set at an angle to the vertical direction, the braking device may be contained within the servo motor attached to the machine tool. If another axis, different from the X-axis, is set to encompass the vertical direction, the braking device may be contained within the servo motor that controls that other axis. For example, if the Y-axis is set to encompass the vertical direction, the braking device may be contained within the servo motor that controls the Y-axis.

[0039] Next, the operation of the brake device with a mounting hub will be described. Fig. Figure 3 shows the operation of the brake device according to the embodiment. Fig. Section 3 describes the operation of the brake 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 brake device. Fig. 3. Configurations that differ from those needed for description have been omitted.

[0040] The in Fig. The brake device 711x shown comprises an externally toothed wheel 7111x, an internally toothed wheel 7112x, friction plates 7113x, a fixed plate 7114x, a pressure plate 7115x, a housing 7116x, an electromagnetic coil 7117x, and a spring 7118x. The externally toothed wheel 7111x and the internally toothed wheel 7112x are examples of the mounting hub claimed in the claims.

[0041] The externally toothed gear 7111x engages 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. Figure 4 shows an example of a structure of the mounting hub of the brake device according to the embodiment.

[0042] According to Fig. For example, a through hole is provided in the externally toothed gear 7111x, and the shaft 713x is inserted into the through hole and attached to it. The externally toothed gear 7111x rotates around the axis of the shaft 713x synchronously with the rotation of the shaft 713x.

[0043] The externally toothed gear 7111x is equipped with several external teeth 7119x along its circumference. The internally toothed gear 7112x is equipped with several internal teeth 7120x along its circumference. When the brake device 711x is used, the externally toothed gear 7111x and the internally toothed gear 7112x are arranged in a positional relationship such that the several external teeth 7119x and the several internal teeth 7120x, which are in Fig. As shown in Figure 4, the internally toothed gear 7112x interlocks. At this moment, the internally toothed gear 7112x is movable in the X-axis direction relative to the externally toothed gear 7111x. When the brake is released, the internally toothed gear 7112x rotates synchronously with the rotation of the externally toothed gear 7111x.

[0044] A specific amount of clearance is intentionally preset between the externally toothed gear 7111x and the internally toothed gear 7112x. Clearance is an intentionally provided gap where the gears mesh. An optimal clearance value is determined, for example, depending on the operation of the press plate 7115x, brake specifications, ease of assembly, etc. The unit of measurement for the clearance is, for example, "arcminute." An "arcminute" is a unit of angular quantity representing one-sixtieth of a degree or "°." In the present embodiment, "°" is used as the unit of measurement representing the clearance.

[0045] Referring again to Fig. The friction plates 7113x are coupled to the internally toothed wheel 7112x. The friction plates 7113x rotate synchronously with the rotation of the internally toothed wheel 7112x. The fixed plate 7114x, for example, serves to limit the movement of the friction plates 7113x away from the side of the motor body 712x when the brake is switched from the off state to the on state.

[0046] In Fig. 3. When the brake is released, 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 acts to attract the pressure plate 7115x to the electromagnetic coil and move it toward the side of the motor body 712x. This separates the friction plates 7113x from the fixed plate 7114x and the housing 7116x. The friction plates 7113x then have no friction with the fixed plate 7114x and the housing 7116x, so there is no restriction on their rotation. Therefore, the externally toothed gear 7111x can rotate synchronously with the rotation of the internally toothed gear 7112x, and the friction plates 7113x can rotate synchronously with the shaft 713x.

[0047] In Fig. 3. When the brake is engaged, the current flow in the electromagnetic coil 7117x is stopped, causing the electromagnetic force to disappear, and the elasticity of the spring 7118x moves the pressure plate 7115x away from the motor body 712x. This causes the friction plates 7113x to contact the pressure plate 7115x and the fixed plate 7114x and become wedged between them, and the rotation of the friction plates 7113x is restricted by the frictional force. Therefore, the rotation of the internally toothed gear 7112x, which is coupled to the friction plates 7113x, is restricted, and the rotation of the externally toothed gear 7111x and the shaft 713x of the motor via the gears is stopped.

[0048] If the brake is applied immediately after the X-axis servo motor 71x stops in an emergency, etc., the [unclear text] stops in Fig. The two gliders 813x shown have fallen due to gravity by the amount of play provided between the externally toothed wheel 7111x and the internally toothed wheel 712x. In an emergency stop, etc., the fall of the glider 813x can therefore be stopped by the braking device 711x.

[0049] In normal machining operations, other than vibration cutting, the X-axis movement for machining is performed in one direction. For example, each of the external teeth 7119x, which is provided on the externally toothed wheel 7111x, engages in Fig. As shown in Figure 4, each external tooth 7119x, provided on the external gear 7111x, is in contact with a pair of adjacent teeth of the multiple internal teeth 7120x, which are provided on the internal gear 7112x, and is in contact with only one of the pair. In contrast, because micro-vibrations associated with vibratory cutting are superimposed on the processing motion, during vibratory cutting, each external tooth 7119x provided on the external gear 7111x is repeatedly in contact with both teeth of the pair of adjacent internal teeth 7120x, which mesh with the external tooth 7119x, on the internal gear 7112x, for example, in one cycle of the micro-vibrations associated with vibratory cutting.Therefore, the multiple external teeth 7119x provided on the externally toothed gear 7111x and the multiple internal teeth 7120x provided on the internally toothed gear 7112x wear down faster than in a case where only normal processing is carried out, and the end of the braking device's service life is reached sooner. If the servo motor continues to be used in a situation where the braking device has reached the end of its service life, during an emergency stop, etc., for example, the slider 813x of the X-axis servo motor 71x may fall further than expected and collide with other mechanical structures, which can lead to a failure. Therefore, the braking device must be replaced. In the numerical control device that enables the machine tool to perform vibratory 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 vibratory cutting than by wear caused by braking operation. The micro-vibrations associated with vibratory cutting are, for example, vibrations based on the vibration conditions that cause the tool bit to vibrate during vibratory cutting, which are transmitted to the braking device 711x while the vibratory cutting is being performed.

[0050] Referring again to Fig. 1. According to the present embodiment, the interpolation processing unit 48 estimates the deterioration of the braking device based on the duration of the vibratory cutting operation. In particular, the interpolation processing unit 48 comprises a timing unit 481, an estimation unit 482, a modification unit 483, a waveform generation unit 484, and a vibration motion value generation unit 485.

[0051] The timing unit 481 measures the execution time of the vibratory cutting process. Specifically, the timing unit 481 stores, for example, an accumulated value of the duration during which the vibratory cutting process is carried out in a braking device. The timing unit 481 also determines whether the accumulated value of the vibratory cutting execution time is greater than or equal to a predetermined value.

[0052] Estimation unit 482 estimates the deterioration of the braking device 711x based on the number of cycles of micro-vibrations associated with vibratory cutting. Specifically, unit 482 estimates the deterioration of the braking device 711x based on, for example, the execution time of the vibratory cutting, measured by the timing unit 481, and the vibration frequency of the vibratory cutting. The vibration frequency of the vibratory cutting is, for example, a frequency set to generate the micro-vibrations during the vibratory cutting process. The number of cycles of micro-vibrations associated with the vibratory cutting can be calculated from the execution time of the vibratory cutting and the vibration frequency of the vibratory cutting process.The estimation unit 482 can also consider 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 micro-vibrations associated with vibration cutting.

[0053] In particular, the estimation unit 482 estimates the deterioration of the braking device 711x by referring to deterioration progression information, which shows the relationship between the duration of the vibratory cutting operation and the progression of the braking device's deterioration. The deterioration progression information also includes information about the vibration frequency, which is a prerequisite for vibratory cutting. The longer the duration of the vibratory cutting operation, the more the deterioration of the braking device progresses, and the deterioration progression information shows the degree of deterioration progress.The deterioration progression information, for example, shows the relationship between the duration of the vibration cutting process and a wear value of the mounting hub contained in the braking device. In other words, it shows that the longer the duration of the vibration cutting process, the greater the progression of wear on the mounting hub of the braking device. The wear value of the mounting hub is the value of the wear that occurs, for example, between the externally toothed gear 7111x and the internally toothed gear 7112x. The wear value is obtained, for example, based on the clearance value between the externally toothed gear 7111x and the internally toothed gear 7112x.

[0054] It should be noted that the information showing the relationship between the duration of vibratory cutting and the wear value of the brake unit's mounting hub is based, for example, on measurements obtained beforehand by conducting a durability test for the vibratory cutting duration on the brake unit with the same or a similar machine configuration as the 711x brake unit. Specifically, the information is based on measurements of the brake unit's mounting hub clearance, obtained at several points during the vibratory cutting process. The brake unit used for the durability test can be of the same type as the 711x brake unit.

[0055] The vibration frequency as a prerequisite for the measurement is, for example, 166.7 Hz on average. This average of 166.7 Hz is achieved, for example, firstly, by setting various vibration frequencies for the test as follows: one at a vibration frequency of 166.7 Hz, at least one at vibration frequencies below 166.7 Hz, and at least one at vibration frequencies above 166.7 Hz; and further, by repeating the vibration cutting operation using the set vibration frequencies in increments such that the average vibration frequency of the vibration cutting performed over a predetermined duration is 166.7 Hz. Alternatively, the measurement can be performed with the vibration frequency, which is the prerequisite for the measurement, set to a predetermined value, for example, 166.7 Hz.The vibration frequency, which is the prerequisite for the measurement, need not be included in the deterioration progression information. In this case, the estimation unit 482 can refer to the deterioration progression information and the vibration frequency as the prerequisite for the measurement, which is associated with the deterioration progression information.

[0056] The modification unit 483 modifies the vibration conditions of the vibratory cutting process based on the deterioration estimate provided by the estimation unit 482. Specifically, the modification unit 483, for example, changes the number of vibration cycles per spindle rotation (numerical value) and / or the spindle rotation speed (r / min) to extend the service life of the brake 711x, in other words, to slow the progression of deterioration of the brake 711x. This changes the vibration frequency (Hz) of the micro-vibrations associated with the vibratory cutting process. For example, the modification unit 483 specifically reduces the number of vibration cycles per spindle rotation (numerical value) and / or the spindle rotation speed (r / min) compared to the pre-modification values ​​to decrease the vibration frequency (Hz) of the micro-vibrations associated with the vibratory cutting process.

[0057] The waveform generation unit 484 generates the vibration waveform as the basic waveform of the vibration based on the information received from the analysis processing unit 45. If the modification unit 483 changes the vibration conditions, the waveform generation unit 484 generates a vibration waveform based on the changed vibration conditions.

[0058] The vibration motion value generation unit 485, for example, obtains 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.

[0059] 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 the vibration cutting based on the vibration motion value sent by the vibration motion value generation unit 485, for example by controlling the X-axis servo motor 71x.

[0060] The process, which is carried out by the Numerical Control Device 1, configured as described above, is performed using Fig. 5 and Fig. 6 described. Fig. Figure 5 shows an example of the process carried out by the numerical control device according to the embodiment. In the present embodiment, it is assumed that the vibration frequency of the vibratory cutting is 166.7 Hz before the modification. It is further assumed that the vibration frequency of the vibratory cutting, as the precondition of the information showing the relationship between the execution time of the vibratory cutting and the wear value of the mounting hub of the brake device, to which the estimation unit 482 refers, is on average 166.7 Hz.

[0061] According to Fig. 5. When the vibratory cutting process is started, the timing unit 481 begins measuring the execution time of the vibratory cutting (step S51). Upon receiving a command to start cutting, the timing unit 481 starts, while the vibratory cutting mode is active, for example, in particular, measuring the execution time of the vibratory cutting. When the When the vibratory cutting process ends, the timing unit 481 stops measuring the execution time of the vibratory cutting. The timing unit 481 stops measuring the execution time of the vibratory cutting, for example, upon receiving a command to stop cutting while the vibratory cutting mode is active. At this moment, the timing unit 481 adds the duration measured in step S51 to the accumulated execution time measured in the past and stores the result as the new accumulated execution time.

[0062] When the timing unit 481 finishes measuring the execution time of the vibratory cutting operation, the estimating unit 482 estimates the deterioration of the brake device 711x based on the execution time of the vibratory cutting operation measured by the timing unit 481 and the vibration frequency of the vibratory cutting operation (step S52). Specifically, the estimating unit 482 refers to the deterioration progression information to estimate the deterioration of the brake device 711x. For example, the estimating unit 482 estimates the deterioration of the brake device 711x based on information showing the relationship between the execution time of the vibratory cutting operation and the wear value of the brake device's mounting hub.

[0063] Fig. Figure 6 shows an example of the information demonstrating the relationship between the execution time of the vibration cutting and the wear value of the mounting hub of the brake device according to the embodiment. For the in Fig. The information shown in Figure 6 assumes that the vibration frequency, as the precondition for the measurement, is an average of 166.7 Hz. Fig. Figure 6 shows that the play, more precisely the play between the externally toothed gear 7111x and the internally toothed gear 7112x, increases with increasing duration of the vibratory cutting operation. The estimating 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 duration of the vibratory cutting operation and the wear value of the mounting hub, and by obtaining the play associated with the duration of the vibratory cutting operation, which was measured by the timing unit 481. The graph in Fig. Figure 6 shows the relationship between the execution time of the vibratory cutting and the wear value of the brake device's mounting hub in the case where the vibratory cutting process continues at an average frequency of 166.7 Hz, during which the execution time of the vibratory cutting and the number of cycles of micro-vibrations associated with the vibratory cutting are approximately proportional. Therefore, the estimating unit 482 can use the information showing the relationship between the number of cycles of micro-vibrations associated with the vibratory cutting, calculated from the average vibration frequency and the execution time of the vibratory cutting, and the wear value of the brake device's mounting hub, as the information for estimating the wear value of the brake device's mounting hub 711x.

[0064] It is also suitable to measure the relationship between the execution time of vibration cutting and the backlash in advance for each of the machine tool configurations, since the relationship depends on conditions such as the shaft diameter of the servo motor, the ball screw drive diameter and the sliding inertia.

[0065] 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). Fig. 6 is the first threshold, for example Th1. For example, the threshold Th1 is defined as the threshold at which the brake device must be replaced.

[0066] In Fig. 5, if it has been determined that the estimated wear value is greater than or equal to the first threshold (yes in step S53), the estimating unit 482, for example, outputs a warning message to the output unit 3 via the output control unit 44 (step S54).

[0067] Fig. Figure 7 shows an example of a screen display output by the numeric control device according to the embodiment. Fig. 7. A message suggesting the replacement of the brake unit 711x is displayed on output unit 3. In Fig. Figure 7 shows the estimation unit 482, in particular via the output control unit 44 on the output unit 3, for example the graph SL1, which shows the relationship between the execution time of the vibration cutting, which is carried out with the included brake device 711x, and the play, as well as the marker M1, which shows the data point from the combination of the execution time of the vibration cutting when the message is output and the value of the play, which is assigned to the execution time of the vibration cutting.

[0068] The execution time of the vibration cutting process is shown here, indicated by the marking M1 in Fig. 7 is greater than or equal to T1. The value of the game, indicated by the marking M1 in Fig. The value indicated in 7 is greater than or equal to the first threshold Th1. The marker M1 is not on the one in Fig. The star shape shown in figure 7 is limited. The marking M1 can be a circle, a rectangle, a triangle, or anything else, as long as it is recognizable by the operator or maintenance personnel.

[0069] In Fig. 7 also displays the message “It is time to replace the X-axis brake unit. Replacement with a spare brake unit is recommended.” as a suggestion to replace the brake unit 711x via the output control unit 44 at the output unit 3.

[0070] This allows the operator or maintenance personnel to recognize when the brake unit needs replacing and to replace the brake unit on the target axle. The parallel display of the graph, along with the message prompting the replacement, allows the operator or maintenance personnel to intuitively grasp the situation.

[0071] In Fig. 7 displays the estimation unit 482, both the graph and the message that prompts the replacement; however, only the message that prompts the replacement can be displayed.

[0072] If the estimation unit 482 determines that the estimated wear value is neither greater than nor equal to the first threshold (no in step S53), it determines whether the estimated wear value is not less than a second threshold (step S55). Fig. 6 is the second threshold value, for example, Th2. This threshold value, Th2, is defined as the threshold that indicates, for example, when the vibration conditions need to be changed to extend the service life of the brake device. Th2 is, for example, a value that is preset in the numerical control device when designing the machine tool. Th2 can also be a value that is set by the operator according to the usage and processing state of the machine tool.

[0073] In Fig. 5. If the estimating 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 modification unit 483 to calculate service life-extending conditions for the brake device 711x. Upon receiving the instruction to calculate the service life-extending conditions, the modification unit 483 calculates the service life-extending conditions according to predetermined conditions (step S56).

[0074] Fig. Figure 8 shows combinations of vibration conditions according to the embodiment. These parameters represent 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 (r / min), 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 modification unit 483 changes the number of vibration cycles per spindle rotation and / or the spindle rotation speed to extend the service life of the brake device 711x.

[0075] The following uses Fig. Eight specific examples of calculating the conditions for extending operating life are described. As in Fig. Figure 8 shows that the vibration conditions before the change are: number of vibration cycles per spindle rotation 2.5 times, spindle rotation speed 4000 rpm, and vibration frequency 166.7 Hz.

[0076] In Fig. For example, the modification 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 modification unit 483 can 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 working backward from the input extended service life.

[0077] Fig. Figure 9 is a schematic diagram showing an example of the vibration waveforms before and after changing the vibration conditions according to the embodiment. Fig. 9 is the vibration frequency before the change, for example 166.7 Hz, and after the change, for example 142.9 Hz. In Fig. In this case, 9 is the vibration cycle CT1 before the change (6.0 ms) and the vibration cycle CT2 after the change (7.0 ms). Fig. Figure 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 zones S, which occur between the nth cycle and the (n+1)th cycle and function as chip-breaking zones for the chip formations produced during vibratory cutting, both before and after the change in vibration conditions. Each air cutting zone S is a zone where, for example, no cutting occurs between the tool bit in the path and the workpiece, and the tool bit simply runs freely, allowing the chips formed up to that point to be separated into pieces.

[0078] As in Fig. As shown in Figure 9, it is possible to reduce the vibration frequency and thereby generate the air cutting ranges S before and after the change in 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 brake device 711x while fulfilling the conditions that enable vibratory cutting, i.e., the conditions that allow cutting operations and break the chips. It should be noted that the in Fig. The 9 vibration waveforms shown can 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 ​​meet the conditions that enable vibration cutting.

[0079] In Fig. In step S56, the modification unit 483 calculates the service life-extending conditions and modifies the vibration conditions of the vibratory cutting process based on these conditions (step S57). The waveform generation unit 484 then generates the vibration waveform based on the modified vibration conditions, and the vibratory cutting process is executed based on this generated waveform. Since the vibration frequency of the vibratory cutting process has been changed from 166.7 Hz to 142.9 Hz, the following occurs: Fig. 4. For example, the cycle in which each external tooth 7119x on the externally toothed wheel 7111x is in contact with the pair of internal teeth 7120x, which engage with the external tooth, on the internally toothed wheel 7112x, is extended, thus reducing the number of contacts per unit of time during vibratory cutting. As a specific result, the wear value of the mounting hub of the brake device 711x per unit of time during vibratory cutting can be reduced. In this case, the service life can be expected to increase by approximately 1.17 times (166.7 Hz / 142.9 Hz) after the modification. It is therefore possible to extend the service life of the brake device 711x.

[0080] The change unit 483 can be configured to present the calculated service life-extending conditions to the operator or maintenance personnel. Fig. Figure 10 shows another example of the screen display output by the numeric control device 1 according to the embodiment. Fig. 10. A message which prompts a change in the vibration conditions in the X-axis servo motor 71x is displayed on output unit 3.

[0081] In Fig. Figure 10 shows the change unit 483, in particular on the output unit 3 via the output control unit 44, for example the graph which shows the relationship between the execution time of the vibration cutting and the play of the brake device 711x, as well as the marker M2, which shows the combination of the execution time of the vibration cutting at the time of the message output and the value of the play which is assigned to the execution time of the vibration cutting. Fig. Figure 10 shows, for example, a forecast graph DL1, represented by a dashed line, from the change control unit 483 to the output control unit 44. The forecast graph DL1 is a graph that shows by how much the service life can be extended if the modified vibration conditions are set at the time the message is output.

[0082] The execution time of the vibration cutting process, indicated by the marking M2, is shown here. Fig. As shown in 10, T2 is greater than or equal to T1 and T1 is less than or equal to T2. The one in Fig. The value of the game indicated by the marker M2 is greater than or equal to the second threshold Th2 and less than the first threshold Th1. The marker M2 is not on the Fig. The star shape shown in 10 is limited. 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.

[0083] In Fig. On output unit 3, output control unit 44 displays a message on change unit 483: “The replacement time of the brake device on the X-axis can be extended by approximately 2 hours, relative to the duration of the vibratory cutting operation, and by approximately 24 hours, relative to the duration of the current machining operation, by changing the vibration conditions of the vibratory cutting operation. Please arrange for the brake device replacement earlier.” This message suggests changing 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 consisting of normal processing and vibratory cutting processing with a ratio of, for example, 11:1.Converting the duration of the vibration cutting process into the duration of the current machine operation and displaying the converted duration alongside the vibration cutting duration can make the message more understandable for the operator or maintenance personnel. Fig. For example, the change unit 483 also displays the expected service life in the event that the vibration conditions are not changed, as a note of "12 hours remaining" via the output control unit 44. Fig. For example, the change unit 483 also displays the extended period of service life that can be achieved when the vibration conditions are changed, as a note of “+2 hours” via the output control unit 44.

[0084] This allows the operator or maintenance personnel to recognize the need to change the vibration conditions of the vibratory cutting machine and to decide whether or not to change them. As a specific response, the operator or maintenance personnel can change the vibration conditions for the Numerical Control Unit 1 by pressing the button in Fig. Press button B1, as shown in Figure 10, to change the vibration cutting operation. The operator or maintenance personnel can choose not to adjust the changed vibration conditions for the Numerical Control Unit 1 (NCU) to continue vibration cutting with the vibration conditions before the change by pressing button B2. The parallel display of the graph, along with the message prompting the change of vibration conditions, allows the operator or maintenance personnel to intuitively understand the situation. Pressing button B1 extends the service life of the 711x brake unit.

[0085] The operator or maintenance personnel can modify the vibration conditions of the vibratory cutting unit using vibration conditions determined from past experience with the processing conditions, instead of using vibration conditions calculated by the modification unit 483. The modification unit 483 can display a graph on output unit 3 via output control unit 44, showing, for example, the remaining service life of the brake unit 711x based on the vibration conditions determined by the operator or maintenance personnel. The modification unit 483 can also display the changes made to the vibration conditions via output control unit 44. In particular, the modification unit 483 displays, for example, the vibration conditions before and after the change on output unit 3.The change unit 483 can display various vibration conditions as options after the change via the output control unit 44 and allow the operator or maintenance personnel to select one.

[0086] The second threshold Th2 is not limited to a single setting as described above. Two or more second thresholds Th2 can be set. For example, a case is assumed in which two second thresholds Th21 = 0.8 and Th22 = 1.0 are in the Fig. The 6 graphs shown are set, and the vibration conditions before the change are “the number of vibration cycles per spindle rotation: 2.5”, “the spindle rotation speed: 4000 rpm” and “the vibration frequency: 166.7 Hz”, shown in Fig. 8. For example, if the estimated value of the play is greater than or equal to Th21 and less than Th22, the change unit 483 displays a message on output unit 3 via output control unit 44, prompting a change in the vibration conditions to "number of vibration cycles per spindle rotation: 2.5", "spindle rotation speed: 3333 rpm", and "vibration frequency: 142.9 Hz". After some time, if the estimated value of the play is greater than or equal to Th22 and less than Th1, the change unit 483 displays a message on output unit 3 via output control unit 44, prompting a change in the vibration conditions to "number of vibration cycles per spindle rotation: 1.5", "spindle rotation speed: 3333 rpm", and "vibration frequency: 83.3 Hz".

[0087] In this case, the modification unit 483 changes the vibration frequency from 166.7 Hz to 142.9 Hz in the first modification and from 142.9 Hz to 83.2 Hz in the second modification to further reduce the frequency, thereby extending the service life. As described above, by setting various threshold values ​​and providing a way to further modify the vibration conditions once changed, it is possible to react flexibly to unexpected changes in operating rules, for example, if the brake device replacement time changes in the meantime.

[0088] In Fig. 5, if it is determined that the estimated wear value is not greater than or equal to the second threshold (no in step S55), the estimation unit 482 terminates the process.

[0089] According to the above embodiment, the control calculation unit 4 of the numerical control device 1, which causes the machine tool to perform the vibratory cutting by controlling 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 micro-vibrations associated with the vibratory cutting.

[0090] This enables the operator or maintenance personnel, for example, to anticipate the replacement time, etc., of the brake device 711x by referring to the deterioration estimate provided by the estimation unit 482, and therefore to take appropriate action before a fault or malfunction, etc., occurs.

[0091] According to the present embodiment, it is therefore possible to detect the deterioration of the servo motor's braking device caused by vibration cutting.

[0092] In Fig. Section 6 describes that the threshold values ​​Th1 and Th2 are approximately 1.2 and 1.0, respectively, but they are not limited to these values. For example, the way wear progresses in the mounting hub depends on the machine configurations, especially the size and shape, etc., of the gears that form the mounting hub. Therefore, the threshold values ​​Th1 and Th2 should be optimally set according to the machine configurations.

[0093] The vibration frequency, which is a prerequisite for the in Fig. The graph shown in Figure 6 is described as an example for the case of an average frequency of 166.7 Hz, but the vibration frequency is not limited to this. For example, the same control can be carried out using the information showing the relationship between the execution time of vibration cutting, which is carried out at a lower vibration frequency, for example an average of 30.3 Hz, and the wear value of the mounting hub, and the same effect can be achieved as a result. modification

[0094] The embodiment of the present disclosure has been described above. However, various modifications and applications are possible when implementing the present disclosure. In the embodiment described above, the case is achieved in which the change in vibration conditions and the output of the estimation result to the operator, etc., are based on the deterioration estimate provided by the estimation unit 482. In the modification, the case is described 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 deterioration estimate provided by the estimation unit 482.

[0095] Fig. Figure 11 shows a configuration example of a Numerical Control Device 1A according to the modification. The Numerical Control Device 1A comprises the input control unit 2, the output unit 3, and a control calculation unit 4A. Fig. Figure 11 shows the drive unit 7, for example, as a component of the machine tool. The drive unit 7 can be a separate component from the machine tool.

[0096] 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 switching unit 47, an interpolation processing unit 48A, the acceleration / braking processing unit 49, the axis data input / output unit 50 and a test unit 51.

[0097] 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 switching unit 47, the acceleration / braking processing unit 49 and the axis data input / output unit 50 are identical to those of the embodiment described above and are therefore omitted from the following description.

[0098] The interpolation processing unit 48A according to the modification comprises the timing unit 481, an estimation unit 482A, the modification unit 483, the waveform generation unit 484, and the vibration motion value generation unit 485. The timing unit 481, the modification unit 483, the waveform generation unit 484, and the vibration motion value generation unit 485 are identical to those of the embodiment described above and are therefore omitted from the following description.

[0099] The estimating unit 482A according to the modification has, in addition to the functions of the estimating unit 482 according to the embodiment described above, the function of determining whether or not the brake test is to be carried out, based on the estimated wear value.

[0100] The test unit 51 performs the brake test. The test unit 51 performs the brake 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.

[0101] The test control unit 511 controls the brake test. For example, upon receiving the instruction to perform the brake test from the estimating unit 482, 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. Specifically, the test control unit 511 switches the brake of the brake device 711x from the off state to the on state after the output of the command to stop the rotation of the X-axis servo motor 71x has been verified.

[0102] The measuring unit 512, for example, measures the play in the mounting hub of the brake device 711x. Specifically, the measuring unit 512 measures the value of the play between the externally toothed gear 7111x and the internally toothed gear 7112x. Because the play increases proportionally to the duration of the vibratory cutting process, measuring the play allows for a more precise determination of the degree of deterioration.

[0103] 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 control of 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 because the brake has been switched on, i.e., at the moment when the counter value no longer changes. The value of the FB counter is transmitted, for example, from detector 72x via the X-axis servo control unit 73x, the axis data input / output unit 50, the acceleration / braking processing unit 49, and the interpolation processing unit 48 to measuring unit 512.

[0104] The measuring unit 512 calculates the rotation angle of the mounting hub when the X-axis servo motor 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, for example, to the estimating unit 482A.

[0105] The backlash value to be calculated can vary depending on, for example, the relative position relationship at the moment the brake is applied, between the outer teeth 7119x of the external gear 7111x and the inner teeth 7120x of the internal gear 7112x in the X-axis servomotor 71x. Therefore, it is suitable for test unit 51 to perform the brake tests several times in order to calculate the average or maximum backlash value obtained in each test as the new backlash value. If the tooth ratio between the gear on the motor shaft side and the gear on the brake device side, which meshes with the aforementioned gear, is not 1:1, it is also suitable to calculate the backlash taking the tooth ratio into account.

[0106] The process, which is carried out by the Numerical Control Device 1A configured as described above, is performed using Fig. 12 and Fig. 6 described. Fig. Figure 12 shows an example of the process carried out by the Numerical Control Device 1A according to the modification.

[0107] In Fig. 12 are steps S121 and S122, which are the same as steps S51 and S52, which are in Fig. 5 are shown.

[0108] 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). In this case, the second threshold value is, for example, Th2, shown in Fig. 6.

[0109] In Fig. 12. If the estimating 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 test unit 51 to perform the brake test. Upon receiving the instruction from the estimating unit 482A, the test unit 51 performs the brake test (step S124).

[0110] Upon receiving the instruction to perform the brake test from the estimating unit 482, the test control unit 511 switches, in particular, for example, the brake of the brake device 711x of the X-axis servo motor 71x from the off state to the on state.

[0111] 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 control of detector 72x at the moment the brake is switched on and the value of the FB counter at the moment the rotation of the X-axis servo motor 71x is stopped by the switched-on brake. The measuring unit 512 calculates the rotation angle of the mounting hub when the X-axis servo motor 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, for example, to the estimation unit 482A as the measured value of the brake test.

[0112] In Fig. 12. Upon receiving the brake test measurement from measuring unit 512, estimation unit 482A determines whether the received brake test measurement is greater than or equal to the first threshold value (step S125). In this case, the first threshold value is, for example, Th1, shown in Fig. 6.

[0113] In Fig. 12. If it is determined that the brake test measurement is greater than or equal to the first threshold value (yes, in step S150), the estimating unit 482A, for example, outputs the warning indicator to the output unit 3 via the output control unit 44 (step S126). The output method is the same as in the embodiment described above.

[0114] If it is determined that the brake test measurement is not greater than or equal to the first threshold (no, step S125), the estimation unit 482A determines whether the brake test measurement is greater than or equal to the second threshold (step S127). In this case, the second threshold is, for example, Th2, shown in Fig. 6.

[0115] In Fig. 12. If it is determined that the brake test measurement is greater than or equal to the second threshold (yes, in step S127), the estimating unit 482A, for example, instructs the modification unit 483 to calculate the service life-extending conditions of the brake device 711x. Upon receiving the instruction to calculate the service life-extending conditions, the modification unit 483 calculates the service life-extending conditions according to predetermined conditions (step S128). The calculation method for the service life-extending conditions is the same as that of the embodiment described above.

[0116] In Fig. Step S129 is the same as step S57, shown in Fig. 5.

[0117] In Fig. 12. If it is determined that the estimated wear value is not greater than or equal to the second threshold (no in step S123), the estimation unit 482A terminates the process. Fig. 12, if it is determined that the measured value of the braking value is not greater than or equal to the second threshold (no in step S127), the estimation unit 482A terminates the process.

[0118] According to the modification, the control unit 4A of the numerical control device 1A, which causes the machine tool to perform vibratory cutting by controlling the servo motor with the brake, also includes, for example, the test unit 51, which performs the brake test of the brake 711x, in addition to the estimation unit 482A, which estimates the deterioration of the brake 711x based on the duration of the vibratory cutting operation. The control unit 4A estimates the deterioration of the brake based on the deterioration estimate, which is based on the duration of the vibratory cutting operation, and the result of the brake test. This allows for a more accurate estimation of the deterioration of the brake 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 design

[0119] In the embodiment above, the estimating unit 482 estimates the deterioration of the brake device by estimating the wear value of the brake device's mounting hub based on the duration of the vibratory cutting operation, 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 duration of the vibratory cutting operation and its deterioration can be detected. For example, the estimating unit 482 can estimate the deterioration of the brake device by estimating the wear value of the brake device's friction plates.

[0120] Fig. Figure 13 shows the operation of the braking device according to the alternative embodiment. Fig. 13 describes the operation of the braking device when the brake is switched on and when the brake is switched off, 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 in Fig. 3 shows the brake device 711x in the embodiment described above. Fig. Three configurations have been omitted that differ from those needed for the description.

[0121] The in Fig. The brake device 911x shown in Figure 13 is a type of brake device without the mounting hub, in contrast to a type of brake device with the mounting hub, which is shown in Figure 13. Fig. Figure 3 shows the braking device 911x. It comprises a friction plate 9111x, a pressure plate 9112x, an electromagnetic coil 9113x, a spring 9114x, and a housing 9115x. The friction plate 9111x is attached to the shaft 713x and rotates with the rotation of the shaft 713x.

[0122] In Fig. 13. When the brake is released, 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, which attracts the pressure plate 9112x to the electromagnetic coil and moves it to the opposite side of the motor body 712x. This separates the friction plate 9111x from the pressure plate 9112x. The friction plate 9111x then 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.

[0123] In Fig. 13. When the brake is applied, the current flow in the electromagnetic coil 9113x is stopped, causing the electromagnetic force to disappear, and 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 limited by the frictional force. Therefore, the rotation of the shaft 713x with the attached friction plate 9111x stops.

[0124] In the numerical control device that enables the machine tool to perform vibratory cutting, the friction plate 9111x of the brake unit 911x is a component that experiences greater wear during vibratory cutting than during braking operation, similar to the mounting hub of the brake unit 711x in a brake unit type with a mounting hub. Therefore, in a brake unit 911x without a mounting hub, the deterioration of the brake unit 911x can be estimated by estimating the wear value of the friction plate 9111x of the brake unit 911x based on the duration of vibratory cutting operation.

[0125] In this case, the estimating unit 482 uses the information showing the relationship between the execution time of the vibratory cutting and a duty cycle during which the brake is switched off, as the information showing the relationship between the execution time of the vibratory cutting using the X-axis servomotor 71x and the wear value of the friction plate 9111x of the brake device 911x. The duty cycle during which the brake is switched off is, for example, the time that elapses until the pressure plate 9112x is attracted to the electromagnetic coil 9113x after the current in the electromagnetic coil 9113x is switched off by switching off the brake, as shown in Fig. 13, to begin flowing. As the friction plate 9111x wears, the distance between the electromagnetic coil 9113x and the friction plate 9111x increases. With this increasing distance, the inrush current required when the brake is released also increases. A specific amount of time is then needed for the inrush current to rise to a certain value. However, as this value increases, the time from when the brake release command is issued until the motor's rotational speed reaches a target value also increases. In brake unit 911x of a type without the mounting hub, the deterioration of the friction plate 9111x therefore becomes a bottleneck in operation, necessitating replacement of the brake unit 911x.

[0126] The information showing the relationship between the duration of vibratory cutting and the inrush current while the brake is off is based, for example, on measurements obtained beforehand by conducting a durability test for vibratory cutting duration on a brake unit of the same machine configuration. Estimation unit 482 estimates the deterioration of brake unit 911x based on the information showing the relationship between the duration of vibratory cutting and the duty cycle of the friction plate when the brake is off.The estimating unit 482 estimates the deterioration of the brake device 911x, for example, by setting the first and second thresholds in the same manner as described in the above embodiment with regard to the information showing the relationship between the execution time of the vibration cutting and the duty cycle when the brake is off. The estimating unit 482 can be configured to perform the brake test after the estimation has been made, in the same manner as described in the modification of the above embodiment.

[0127] In the embodiment described above, the numerical control device 1 comprises the input control unit 2 and the output unit 3, but the configuration is not limited thereto. In particular, the input control unit 2 or the output unit 3 can be attached externally to the numerical control device 1 in order to configure the numerical control device 1 without the input control unit 2 or the output unit 3.

[0128] In the embodiment described above, the numerical control device 1 performs the vibratory cutting by vibrating the tool bit; however, the area to be vibrated is not limited to the tool bit. For example, the numerical control device 1 can vibrate the workpiece to perform the vibratory cutting.

[0129] Now, the 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 are described. Fig. Figure 14 shows a hardware configuration example of the control processing unit according to the embodiment and the modification. Because control processing units 4 and 4A have the same hardware configuration, the hardware configuration of control processing unit 4 is discussed here.

[0130] The control computing unit 4 can be implemented with a control circuit 100, i.e. using a processor 101 and a memory 102, as shown in Fig.14. An example of a 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).

[0131] The control unit 4 is implemented by processor 101, which reads and executes a program stored in memory 102 to operate the control unit 4. The program can be described as a recipe for instructing the computer to carry out the procedures or processes of the control unit 4. Memory 102 is also used as temporary storage when processor 101 performs various processes.

[0132] The program to be executed by Processor 101 can be a computer program product provided as a computer-readable and non-volatile storage medium containing several instructions that the computer can execute to perform data processing. When Processor 101 executes the program, the computer performs the data processing through these instructions.

[0133] Alternatively, the control processing unit 4 can be implemented using dedicated hardware. The functions of the control processing unit 4 can be implemented partly through dedicated hardware and partly through software or firmware.

[0134] The present disclosure allows for various embodiments and modifications without deviating from the broader spirit and scope of the present disclosure. The embodiments described above are intended to illustrate the present disclosure and are not intended to limit its scope. 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 considered as being within the scope of the present disclosure. Industrial availability

[0135] According to the present disclosure, it is possible to provide a numerical control device which is designed to detect the deterioration of the braking device which brakes the servo motor caused by the vibration cutting. Reference symbol list 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 units 44 Output control unit 45 Analysis processing unit 46 Control signal processing unit 47 PLC switching unit 48, 48A Interpolation Processing Unit 481 timing unit 482, 482A Estimation unit 483 Change Unit 484 Waveform Generation Unit 485 Vibration Motion Value Generation Unit 49 Acceleration / Deceleration Processing Unit 50 axis data input / output units 51 test units 511 Test control unit 512 Unit of measurement 7 Drive unit 71x X-axis servo motor 72x Detector 73x X-axis servo control unit 711x brake device 7111x externally toothed wheel 7112x internally toothed wheel 7113x, 9111x friction plate

Claims

[1] Numerical control device (1, 1A) which controls a servo motor (71x) to cause a machine tool to perform vibratory cutting, wherein the numerical control device (1, 1A) comprises: an estimation unit (482, 482A) which estimates a deterioration of a braking device (711x) for braking the servo motor (71x) based on a number of cycles of micro-vibrations associated with vibratory cutting. [2] Numerical control device (1, 1A) which controls a servo motor (71x) to cause a machine tool to perform vibratory cutting, wherein the numerical control device (1, 1A) comprises: an estimation unit (482, 482A) which estimates a deterioration of a braking device (711x) for braking the servo motor (71x) based on a duration of the vibratory cutting and a vibration frequency of the vibratory cutting. [3] Numerical control device (1, 1A) according to claim 1 or 2, wherein the estimating unit (482, 482A) estimates the deterioration of the braking device (711x) by reference to deterioration progression information which indicates a relationship between the execution time of the vibration cutting and a progression of the deterioration of the braking device (711x). [4] Numerical control device (1, 1A) according to any one of claims 1 to 3, wherein the estimating unit (482, 482A) estimates a wear value of a mounting hub provided in the brake device (711x). [5] Numerical control device (1A) according to any one of claims 1 to 4, further comprising: a test unit (51) for performing a brake test of the brake device (711x), where the estimation unit (482A) estimates the deterioration of the brake device (711x) based on the deterioration estimation result and a brake test result. [6] Numerical control device (1, 1A) according to any one of claims 1 to 5, further comprising a modification unit (483) which modifies vibration conditions of the vibration cutting based on the deterioration estimate in order to slow down the progression of deterioration of the braking device (711x). [7] Numerical control device (1, 1A) according to claim 6, further comprising a modification unit (483) which modifies vibration conditions of the vibratory cutting based on the deterioration estimation result in order to reduce the vibration frequency of the vibratory cutting. [8] Numerical control device (1, 1A) according to one of claims 1 to 7, further comprising an output control unit (44) which outputs the estimated result of the deterioration. [9] Numerical control device (1, 1A) according to claim 8, wherein the output control unit (44) outputs an operating lifetime of the brake device (711x) based on the estimated result of the deterioration.

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