Control device, machine tool, control method, and computer program

Abstract

To provide a controller etc., capable of suppressing a load placed on a transmission mechanism of a tool magazine in braking.SOLUTION: A controller for a machine tool comprises a tool magazine where a plurality of tools are housed, and comprises a power failure determination part which determines whether a power failure occurs, an acceleration / deceleration part which accelerates or decelerates the tool magazine with a first time constant when the power failure determination part determines that no power failure occurs, and a deceleration part which decelerates the tool magazine with a second time constant shorter than the first time constant when the power failure determination part determines that a power failure occurs, the second time constant being shorter than the first time constant.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present technology relates to a control device, a machine tool, a control method, and a computer program for controlling the speed of a tool magazine. [Background technology]

[0002] There is a machine tool that includes a tool magazine that stores tools, a spindle on which the tools are attached, and a control device that controls the driving of the tool magazine and the spindle (see, for example, Patent Document 1). When a power outage occurs, the control device executes a deceleration process for the tool magazine for a predetermined period of time and applies the brakes using a braking unit to maintain safety. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-151816 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the speed of the tool magazine does not decrease sufficiently within the predetermined time, the load during braking acting on the transmission mechanism that transmits power to the tool magazine, such as a reducer, may become excessive.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a control device, a machine tool, a control method, and a computer program that can suppress the load acting on the transmission mechanism of a tool magazine during braking. [Means for solving the problem]

[0006] A control device according to one embodiment of the present disclosure is a control device for a machine tool having a tool magazine that stores a plurality of tools, and includes a power outage determination unit that determines whether or not there is a power outage, an acceleration / deceleration unit that accelerates or decelerates the tool magazine with a first time constant when the power outage determination unit determines that there is no power outage, and a deceleration unit that decelerates the tool magazine with a second time constant shorter than the first time constant when the power outage determination unit determines that there is a power outage.

[0007] In the present disclosure, a first time constant is used to accelerate and decelerate the tool magazine when there is no power outage, and a second time constant shorter than the first time constant is used when there is a power outage, thereby reducing the time required to sufficiently slow down the speed of the tool magazine.

[0008] In one embodiment of the control device disclosed herein, the tools include heavy tools and standard tools lighter than the heavy tools, the second time constant includes a third time constant corresponding to the heavy tools and a fourth time constant corresponding to the standard tools and shorter than the third time constant, and the control device is provided with a storage determination unit that determines whether the tool magazine stores the heavy tool, and when the storage determination unit determines that the tool magazine stores the heavy tool, the deceleration unit decelerates the tool magazine with the third time constant, and when the storage determination unit determines that the tool magazine does not store the heavy tool, the deceleration unit decelerates the tool magazine with the fourth time constant.

[0009] In the present disclosure, when the tool magazine stores heavy tools, a third time constant is used, and when the tool magazine does not store heavy tools, a fourth time constant shorter than the third time constant is used. When storing standard tools, the time required to sufficiently reduce the speed of the tool magazine is shorter than when storing heavy tools, so a fourth time constant shorter than the third time constant is used.

[0010] A control device according to one embodiment of the present disclosure includes a power storage unit that stores power to be supplied to the tool magazine, and the second time constant is based on the time during which the tool magazine can be controlled using the power stored in the power storage unit.

[0011] In the present disclosure, after a power outage, the deceleration process of the tool magazine is completed before the power stored in the power storage unit runs out.

[0012] A control device according to one embodiment of the present disclosure includes a selection unit that selects the primary time constant or the second time constant, and when the power outage determination unit determines that a power outage has occurred, the selection unit selects the second time constant, and the deceleration unit decelerates the tool magazine with the second time constant selected by the selection unit, and when power is restored after a power outage, the selection unit selects the primary constant.

[0013] In the present disclosure, when power is restored after a power outage, the time constant used for acceleration / deceleration processing is returned from the second time constant to the first time constant, and appropriate acceleration / deceleration processing is performed.

[0014] In a control device according to one embodiment of the present disclosure, when the power outage determination unit determines that a power outage has occurred while the tool magazine is rotating at a constant speed, the deceleration unit performs a first deceleration process, when the power outage determination unit determines that a power outage has occurred while the tool magazine is accelerating, the deceleration unit performs a second deceleration process different from the first deceleration process, and when the power outage determination unit determines that a power outage has occurred while the tool magazine is decelerating, the deceleration unit performs a third deceleration process different from the first and second deceleration processes.

[0015] In the present disclosure, an appropriate deceleration process is executed depending on the state of constant speed rotation, acceleration, and deceleration.

[0016] A machine tool according to one embodiment of the present disclosure includes a tool magazine for storing a plurality of tools, a power outage determination unit for determining whether or not there is a power outage, an acceleration / deceleration unit for accelerating or decelerating the tool magazine with a first time constant when the power outage determination unit determines that there is no power outage, and a deceleration unit for decelerating the tool magazine with a second time constant shorter than the first time constant when the power outage determination unit determines that there is a power outage.

[0017] In the present disclosure, a first time constant is used to accelerate and decelerate the tool magazine when there is no power outage, and a second time constant shorter than the first time constant is used when there is a power outage, thereby reducing the time required to sufficiently slow down the speed of the tool magazine.

[0018] A control method according to one embodiment of the present disclosure is a control method for a machine tool equipped with a tool magazine that stores a plurality of tools, which determines whether or not there is a power outage, and if it is determined that there is no power outage, accelerates or decelerates the tool magazine with a first time constant, and if it is determined that there is a power outage, decelerates the tool magazine with a second time constant that is shorter than the first time constant.

[0019] In the present disclosure, a first time constant is used to accelerate and decelerate the tool magazine when there is no power outage, and a second time constant shorter than the first time constant is used when there is a power outage, thereby reducing the time required to sufficiently slow down the speed of the tool magazine.

[0020] A computer program according to one embodiment of the present disclosure is executed by a control device of a machine tool having a tool magazine that stores a plurality of tools, and causes the control device to determine whether there is a power outage, and if it is determined that there is no power outage, to accelerate or decelerate the tool magazine with a first time constant, and if it is determined that there is a power outage, to decelerate the tool magazine with a second time constant that is shorter than the first time constant.

[0021] In the present disclosure, a first time constant is used to accelerate and decelerate the tool magazine when there is no power outage, and a second time constant shorter than the first time constant is used when there is a power outage, thereby reducing the time required to sufficiently slow down the speed of the tool magazine. Effect of the Invention

[0022] In the control device, machine tool, control method, and computer program according to one embodiment of the present disclosure, a first time constant is used to accelerate and decelerate the tool magazine when there is no power outage, and a second time constant shorter than the first time constant is used when there is a power outage, thereby shortening the time required to sufficiently slow down the speed of the tool magazine and suppressing the load acting on the transmission mechanism of the tool magazine when braking. [Brief description of the drawings]

[0023] [Figure 1] 1 is a simplified perspective view of a machine tool according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram of a control device, motors, etc. [Diagram 3] 6 is a graph showing the speed and acceleration of a magazine motor when a power outage occurs during constant speed rotation. [Figure 4] 11 is a graph illustrating the speed and acceleration of a magazine motor when a power outage occurs during acceleration. [Diagram 5] 11 is a graph showing the speed and acceleration of a magazine motor when a power outage occurs during deceleration. [Figure 6] 6 is a flowchart illustrating an acceleration / deceleration process of the tool magazine performed by the control device. [Figure 7] 4 is a flowchart illustrating a deceleration process performed by the control device. [Figure 8] 4 is a flowchart illustrating a time constant restoration process performed by the control device. [Figure 9] 10 is a flowchart illustrating a deceleration process performed by a control device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] (Embodiment 1) The present invention will be described below based on the drawings showing a machine tool according to a first embodiment. In the following description, up, down, front, back, left and right in the drawings will be used. FIG. 1 is a schematic perspective view of the machine tool. The machine tool includes a base 1, a Y-axis direction moving device 2, an X-axis direction moving device 3, a vertical column 5, a Z-axis direction moving device 6, a spindle head 10, a tool changer 7, a control device 80, and the like. The X-axis direction corresponds to the left-right direction, and the Y-axis direction corresponds to the front-back direction. The base 1 is fixed onto the floor surface. The base 1 supports the Y-axis direction moving device 2, the X-axis direction moving device 3, and the vertical column 5. The X-axis direction moving device 3 is disposed on the Y-axis direction moving device 2. A work table 4 is provided on the X-axis direction moving device 3. The work table 4 holds a work.

[0025] The Y-axis direction moving device 2 is equipped with a Y-direction screw shaft extending in the front-rear direction and a nut (not shown). The Y-direction screw shaft is rotated by a Y-axis motor 23 (see FIG. 2), and the nut moves the work table 4 in the front-rear direction. The X-axis direction moving device 3 is equipped with an X-direction screw shaft extending in the left-right direction and a nut (not shown). The X-direction screw shaft is rotated by an X-axis motor 33 (see FIG. 2), and the nut moves the work table 4 in the left-right direction.

[0026] A vertical pillar 5 is disposed behind the Y-axis direction moving device 2. A Z-axis direction moving device 6 is provided in front of the vertical pillar 5. The Z-axis direction moving device 6 is equipped with a Z-direction screw shaft (not shown) and a nut that extend in the vertical direction. The Z-direction screw shaft is rotated by a Z-axis motor 63 (see FIG. 2), and the nut moves the spindle head 10 in the vertical direction.

[0027] The spindle head 10 supports a spindle (not shown). The spindle is rotated by a spindle motor 13 (see Figure 2). One end of a tool holder (not shown) is attached to the lower end of the spindle. The other end of the tool holder holds a tool (not shown). The spindle forms the rotating part, and the spindle motor 13 forms the rotation drive part. A connecting plate 9 protrudes forward from the upright column 5. A tool changer 7 is provided at the tip of the connecting plate 9. The tool changer 7 is located in front of the spindle head 10.

[0028] The tool changer 7 is equipped with a disk-shaped tool magazine 7a. A plurality of tool holding arms (not shown) are provided on the outer periphery of the tool magazine 7a. The tool holding arms detachably hold tool holders and tools. The tool magazine 7a stores a plurality of tools.

[0029] The tool magazine 7a is rotatable around its axis. The tool magazine 7a is rotated by a magazine motor 73 (see FIG. 2) and positions a specific tool at the tool change position. The tool changer 7 replaces the tool attached to the spindle with the next tool at the tool change position based on the up and down movement of the spindle head 10. The tool change position is the lowest end position of the tool magazine 7a. A control device 80 is provided at the rear of the upright pillar 5.

[0030] FIG. 2 is a block diagram of the control device 80, the motors 13, 23, 33, 63, 73, etc. The control device 80 includes a CPU 81, a RAM 82, a storage unit 83, an input / output interface 84, etc. The CPU 81 includes a timer (not shown). The RAM 82 stores various information. The storage unit 83 is rewritable and includes, for example, a non-volatile memory or a hard disk. The non-volatile memory is an EPROM, an EEPROM, a flash memory, etc. The storage unit 83 stores a machining program, an acceleration / deceleration processing program, a deceleration processing program (program product), whether or not the time constant is switched, and a time for timing, etc. The CPU 81 reads each program from the storage unit 83 into the RAM 82 and executes it. Each program may be installed in the storage unit 83 from a recording medium 100, for example, an optical disk or a USB memory, etc., or may be downloaded to the storage unit 83 from a server (not shown) connected to the control device 80 so as to be able to communicate with the control device 80.

[0031] The control device 80 includes a power supply circuit 86, a detection unit 85, and a power storage unit 87. The power supply circuit 86 converts AC power into DC power and supplies power to the control device 80. The detection unit 85 detects the voltage of the power supplied by the power supply circuit 86. The CPU 81 determines that a power outage has occurred when the voltage detected by the detection unit 85 becomes equal to or lower than a threshold. The detection unit 85 may detect a current, and the CPU 81 may determine that a power outage has occurred when the detected current becomes equal to or lower than a threshold. The power storage unit 87 includes, for example, a capacitor or a storage battery. The power supply circuit 86 supplies power to the power storage unit 87. The power storage unit 87 stores power capable of driving and controlling the machine tool for a predetermined time, for example, at least 200 ms, during a power outage.

[0032] The machine tool includes an operation unit 51 and a display unit 52. The operation unit 51 has a keyboard, switches, buttons, a touch panel, etc., and accepts operations by an operator. The display unit 52 has a display screen and displays information based on a display signal, which will be described later. A touch panel may serve as both the operation unit 51 and the display unit 52. A signal from the operation unit 51 is input to the CPU 81, for example, via an input / output interface 84. The CPU 81 outputs a display signal to the display unit 82, for example, via the input / output interface 84.

[0033] The control device 80 includes a drive circuit 71, a servo amplifier 72, and a differentiator 75 corresponding to the magazine motor 73. The magazine motor 73 includes an encoder 74. The drive circuit 71 outputs a command indicating the amount of current to the servo amplifier 72 based on a command from a CPU 81. The servo amplifier 72 receives the command and outputs a drive current to the magazine motor 73.

[0034] The encoder 74 outputs a position feedback signal to the drive circuit 71. The drive circuit 71 executes position feedback control based on the position feedback signal. The position feedback signal indicates the position of the tool magazine 7a in the direction around the axis, that is, the angle.

[0035] The encoder 74 outputs a position feedback signal to the differentiator 75, and the differentiator 75 converts the position feedback signal into a velocity feedback signal and outputs it to the drive circuit 71. The drive circuit 71 executes velocity feedback control based on the velocity feedback signal.

[0036] A current detector 76 detects the value of the drive current output by the servo amplifier 72. The current detector 76 feeds back the value of the drive current to the drive circuit 71. The drive circuit 71 executes current control based on the value of the drive current.

[0037] The tool magazine 7a is equipped with a braking unit 73a. The braking unit 73a comes into contact with the tool magazine 7a and stops the rotation of the tool magazine 7a. In other words, the braking unit 73a is a brake. When a power outage is detected, the control device 80 drives the braking unit 73a after a predetermined time, for example, 200 ms, has elapsed, and stops the tool magazine 7a.

[0038] The control device 80 includes a drive circuit 31, a servo amplifier 32, a differentiator 35, and a current detector 36 corresponding to the X-axis motor 33, and the X-axis motor 33 includes an encoder 34. The X-axis direction movement device 3 includes a brake unit 33a. The drive circuit 31, the servo amplifier 32, the differentiator 35, the X-axis motor 33, the encoder 34, the current detector 36, and the brake unit 33a are the same as those in the tool magazine 7a, and therefore description thereof will be omitted.

[0039] The control device 80 includes a drive circuit 21, a servo amplifier 22, a differentiator 25, and a current detector 26 corresponding to the Y-axis motor 23, and the Y-axis motor 23 includes an encoder 24. The Y-axis direction moving device 2 includes a brake unit 23a. The drive circuit 21, the servo amplifier 22, the differentiator 25, the Y-axis motor 23, the encoder 24, the current detector 26, and the brake unit 23a are similar to those of the tool magazine 7a, and therefore description thereof will be omitted.

[0040] The control device 80 includes a drive circuit 61 corresponding to the Z-axis motor 63, a servo amplifier 62, a current detector 66, and a differentiator 65. The Z-axis motor 63 includes an encoder 64. The Z-axis direction moving device 6 includes a brake unit 63a. The drive circuit 61, the servo amplifier 62, the differentiator 65, the Z-axis motor 63, the encoder 64, the current detector 66, and the brake unit 63a are the same as those in the tool magazine 7a, and therefore description thereof will be omitted.

[0041] The control device 80 is equipped with a drive circuit 11 corresponding to the spindle motor 13, a servo amplifier 12, a current detector 16, and a differentiator 15. The spindle motor 13 is equipped with an encoder 14. The spindle head 10 is equipped with a braking unit 13a. The drive circuit 11, servo amplifier 12, differentiator 15, spindle motor 13, encoder 14, current detector 16, and braking unit 13a are similar to those of the tool magazine 7a, and description thereof will be omitted.

[0042] FIG. 3 is a graph showing the speed and acceleration of magazine motor 73 when a power outage occurs during constant speed rotation. The speed of magazine motor 73 is the rotation speed, and the acceleration is the acceleration of the rotation speed. t0 in FIG. 3 indicates the time when the power outage occurs, and t1 indicates the time when the deceleration process ends. Vm indicates the maximum speed. At indicates the maximum acceleration, and Ab indicates the minimum acceleration. The maximum speed Vm, the maximum acceleration At, and the minimum acceleration Ab are stored in memory unit 83. The operator can operate operation unit 51 to change the maximum speed Vm, the maximum acceleration At, and the minimum acceleration Ab.

[0043] T1a indicates the time constant from when the acceleration of the magazine motor 73 becomes At from 0 to when it becomes 0 again, and T1b indicates the time constant from when the acceleration of the magazine motor 73 becomes At to 0 and the time constant from when the acceleration becomes At to when it becomes At. J1a indicates the gradient of the acceleration from when the acceleration of the magazine motor 73 becomes At to when it becomes 0, that is, the jerk, and J1b indicates the gradient of the acceleration from when the acceleration of the magazine motor 73 becomes At to when it becomes 0, that is, the jerk. The jerk J1a is calculated by the maximum acceleration At / time constant T1b. The jerk J1b is calculated by - the maximum acceleration At / time constant T1b. The jerks J1a and J1b are constant. In this embodiment, At and J1a are positive values, and J1b is a negative value. The time constants T1a and T1b constitute a first time constant. In the initial state, the first time constant is set in the machine tool.

[0044] T2a indicates the time constant until the acceleration of the magazine motor 73 becomes Ab from 0 and becomes 0 again, and T2b indicates the time constant until the acceleration of the magazine motor 73 becomes Ab from 0 and the time constant until the acceleration becomes Ab from 0. The time constant T2a is shorter than the time constant T1a. The time constant T2b is shorter than the time constant T1b. J2a indicates the gradient of the acceleration of the magazine motor 73 from 0 to Ab, that is, the jerk, and J2b indicates the gradient of the acceleration of the magazine motor 73 from Ab to 0, that is, the jerk. The jerk J2a is calculated by minimum acceleration Ab / time constant T2b. The jerk J2b is calculated by - minimum acceleration Ab / time constant T2b. The jerks J2a and J2b are constant. In this embodiment, Ab and J2a are negative values, and J2b is a positive value. The time constants T2a and T2b constitute a second time constant.

[0045] The operator operates the operation unit 51 to input the time constants T1a, T1b, T2a, and T2b. Also, the operator inputs the switching of the time constant, i.e., the validity or invalidity of the switching from the first time constant to the second time constant. The memory unit 83 stores the time constants T1a, T1b, T2a, and T2b, and the validity or invalidity of the switching of the time constants. The memory unit 83 may store the time constants T1a, T1b, T2a, and T2b according to the command of the machining program. The control device 80 executes the acceleration / deceleration process and the deceleration process of the magazine motor 73 based on the time constants T1a, T1b, T2a, and T2b, and the maximum acceleration At and the minimum acceleration Ab.

[0046] 3, before time t0, the control device 80 executes acceleration / deceleration processing of the magazine motor 73 based on the time constants T1a and T1b and the jerks J1a and J1b. That is, from a state of time 0 and speed 0, the acceleration is increased to At at the jerk J1a, the state of acceleration At is maintained for a predetermined time, and the acceleration is decreased to 0 at the jerk J1b. The speed of the magazine motor 73 gradually increases from 0 to a maximum speed Vm, and the maximum speed Vm is maintained until time t0.

[0047] After time t0, that is, after the power failure, the control device 80 executes a first deceleration process based on the time constants T2a and T2b and the jerks J2a and J2b. That is, between time t0 and t1, the acceleration is decreased from the maximum speed Vm to Ab at the jerk J2a, the acceleration Ab state is maintained for a predetermined time, and the acceleration is increased to 0 at the jerk J2b. The speed of the magazine motor 73 gradually decreases from the maximum speed Vm to 0. That is, after the power failure, the tool magazine 7a is decelerated and stopped based on the time constants T2a and T2b and the jerks J2a and J2b. The time constant T2a is, for example, 200 ms or less, which is less than the time during which the machine tool can be driven and controlled by the power stored in the power storage unit 87 after the power failure.

[0048] Fig. 4 is a graph showing the speed and acceleration of the magazine motor 73 when a power outage occurs during acceleration. In Fig. 4, t0, t1, Vm, At, Ab, T1a, T1b, T2a, T2b, J1a, J1b, J2a, and J2b are the same as in Fig. 3. t2 indicates the time when the acceleration switches from a negative value to a positive value, i.e., the time when the acceleration becomes 0. Vt2 indicates the speed of the magazine motor 73 at time t2.

[0049] 4, before time t0, the control device 80 executes acceleration / deceleration processing of the magazine motor 73 based on the time constants T1a and T1b and the jerks J1a and J1b. That is, from a state of time 0 and speed 0, the acceleration is increased to At with the jerk J1a, and the state of the acceleration At is maintained until time t0.

[0050] After time t0, i.e., after the power outage, the control device 80 executes a second deceleration process based on the time constants T2a and T2b and the jerks J2a and J2b. The control device 80 reduces the acceleration from At to 0 at the jerk J2a from time t0 to time t2. As shown in FIG. 4, the speed Vt2 at time t2 is lower than the maximum speed Vm. The speed Vt2 is the upper limit speed in the second deceleration process. The time from time t0 to t2 is shorter than the time constant T1b. That is, deceleration occurs in a shorter time than in the acceleration / deceleration process.

[0051] Based on the time constants T2a and T2b and the jerks J2a and J2b, the control device 80 reduces the acceleration from the speed Vt2 to Ab at the jerk J2a between time points t2 and t1, maintains the acceleration Ab state for a predetermined time, and increases the acceleration at the jerk J2b until it becomes 0. The speed of the magazine motor 73 gradually decreases from the speed Vt2 to 0. That is, after the power outage, the tool magazine 7a decelerates and stops based on the time constants T2a and T2b and the jerks J2a and J2b.

[0052] Fig. 5 is a graph showing the speed and acceleration of the magazine motor 73 when a power outage occurs during deceleration. In Fig. 5, t0, t1, Vm, At, Ab, T1a, T1b, T2a, T2b, J1a, J1b, J2a, and J2b are the same as those in Fig. 3.

[0053] As shown in Fig. 5, before time t0, the control device 80 executes acceleration / deceleration processing of the magazine motor 73 based on the time constants T1a and T1b and the jerks J1a and J1b. That is, the acceleration is increased from a speed of 0 to At at a jerk J1a, the state of the acceleration At is maintained for a predetermined time, and the acceleration is decreased to 0 at a jerk J1b. The speed of the magazine motor 73 gradually increases from 0 to a maximum speed Vm, and the maximum speed Vm is maintained for a predetermined time. After maintaining the maximum speed Vm for a predetermined time, the control device 80 decreases the acceleration to -At at a jerk J1b, and maintains the state of the acceleration -At until time t0.

[0054] After time t0, i.e., after the power outage, the control device 80 executes a third deceleration process based on the time constants T2a and T2b and the jerks J2a and J2b. From time t0 to time t2, the control device 80 reduces the acceleration from -At to Ab with the jerk J2a, maintains the state of the acceleration Ab for a predetermined time, and increases the acceleration with the jerk J2b until it becomes 0. The speed of the magazine motor 73 gradually decreases from the maximum speed Vm to 0. That is, the tool magazine 7a accelerates and decelerates based on the time constants T1a and T1b and the jerks J1a and J1b before the power outage, and decelerates and stops based on the time constants T2a and T2b and the jerks J2a and J2b after the power outage.

[0055] 6 is a flow chart for explaining the acceleration / deceleration process of the tool magazine 7a by the control device 80, which is started when a rotation command for the tool magazine 7a is executed. The CPU 81 outputs a drive signal to the drive circuit 71 (S1).

[0056] The CPU 81 starts the above-mentioned acceleration / deceleration process (S2). As described above, the first time constants, i.e., the time constants T1a and T1b, are set in the initial state. The CPU 81 executes the acceleration / deceleration process based on the time constants T1a and T1b and the jerks J1a and J1b.

[0057] The CPU 81 receives a signal from the detection unit 85 and determines whether a power outage has occurred (S3). If a power outage has not occurred (S3: NO), it determines whether the magazine motor 73 has reached the target position, i.e., the target angle (S4). The drive circuit 71 determines whether the target angle has been reached based on the output value of the encoder 74 and the rotation command. When the magazine motor 73 has reached the target position, the drive circuit 71 outputs a signal indicating that the target position has been reached to the CPU 81. When the signal is input, the CPU 81 determines that the magazine motor 73 has reached the target position, and when the signal is not input, it determines that the magazine motor 73 has not reached the target position.

[0058] If the magazine motor 73 has not reached the target position (S4: NO), the CPU 81 returns the process to step S3. If the magazine motor 73 has reached the target position (S4: YES), the CPU 81 ends the acceleration / deceleration process (S5), and ends the acceleration / deceleration process. If a power outage is detected in step S3 (S3: YES), the CPU 81 executes the deceleration process (S6).

[0059] 7 is a flowchart illustrating the deceleration process by the control device 80. The CPU 81 starts timing (S21), and determines whether or not the switching of the time constant is valid (S22). The CPU 81 accesses the storage unit 83. If the storage unit 83 stores that the switching of the time constant is valid, the CPU 81 determines that the switching of the time constant is valid, and if the storage unit 83 stores that the switching of the time constant is invalid, the CPU 81 determines that the switching of the time constant is invalid.

[0060] If the time constant switching is enabled (S22: YES), the CPU 81 selects the second time constant, that is, the time constants T2a and T2b, as the time constants (S23). The CPU 81 judges whether the magazine motor 73 is rotating at a constant speed (S24). The CPU 81 judges whether the magazine motor 73 is rotating at a constant speed or accelerating based on the previous speed and the current speed acquired by the drive circuit 71 via the encoder 74. If the magazine motor 73 is rotating at a constant speed (S24: YES), the CPU 81 executes the above-mentioned first deceleration process (S25) and judges whether the time measurement has ended (S29). The timer of the CPU 81 ends the time measurement when the time during which the machine tool can be driven and controlled by the power stored in the power storage unit 87 after the power failure, for example, 200 ms, has elapsed since the start of the time measurement. If the time measurement has ended (S29: YES), the brake unit 73a applies braking (S34). That is, the brake unit 73a applies the brakes (see FIG. 6). The CPU 81 ends the deceleration process and the acceleration / deceleration process.

[0061] If the magazine motor 73 is not rotating at a constant speed (S24: NO), the CPU 81 determines whether or not the magazine motor 73 is accelerating (S26). If the acceleration is positive, the CPU 81 determines that the magazine motor 73 is accelerating, and if the acceleration is negative, the CPU 81 determines that the magazine motor 73 is decelerating. If the magazine motor 73 is accelerating (S26: YES), the CPU 81 executes the second deceleration process described above (S27) and determines whether or not the time measurement has ended (S29). If the time measurement has ended (S29: YES), the brake unit 73a applies braking (S34), and the deceleration process and the acceleration / deceleration process are ended.

[0062] If the vehicle is not accelerating (S26: NO), that is, if the vehicle is decelerating, the CPU 81 executes the third deceleration process described above (S28) and determines whether or not the time measurement has ended (S29). If the time measurement has not ended (S29: NO), the process returns to step S29. If the time measurement has ended (S29: YES), the brake unit 73a applies braking (S34), and the deceleration process and the acceleration / deceleration process are terminated.

[0063] In step S22, if the time constant switching is not enabled (S22: NO), the CPU 81 continues the acceleration / deceleration process (S30). The CPU 81 continues the acceleration / deceleration process based on the first time constant, i.e., the time constants T1a and T1b, and the jerks J1a and J1b. The CPU 81 determines whether or not the time measurement has ended (S31). If the time measurement has not ended (S31: NO), the CPU 81 determines whether or not the magazine motor 73 has reached the target position (S32).

[0064] If the magazine motor 73 has not reached the target position (S32: NO), the CPU 81 returns the process to step S31. If the magazine motor 73 has reached the target position (S32: YES), the CPU 81 ends the acceleration / deceleration process (S33), applies braking using the braking unit 73a (S34), and ends the deceleration process and the acceleration / deceleration process.

[0065] In step S31, if the time measurement has ended (S31: YES), the CPU 81 performs braking by the braking unit 73a (S34), and ends the deceleration process and the acceleration / deceleration process.

[0066] After braking by the braking unit 73a, the power supply to the machine tool is turned off due to a power outage. When the power supply to the machine tool is turned on and restored, the control device 80 executes a time constant restoration process. FIG. 8 is a flowchart for explaining the time constant restoration process by the control device 80.

[0067] After the power is turned on, the CPU 81 executes a time constant recovery process. The CPU 81 determines whether or not this is the first startup after a power outage (S41).

[0068] For example, the time when a power outage was detected and the time when the power was turned on are stored in chronological order in the storage unit 83, and the CPU 81 determines that it is the first startup if there is no other time when the power was turned on between the time when the power outage was detected and the most recent time when the power was turned on, i.e., the time when it was determined that the power was on in step S41. Also, a predetermined value may be stored in a predetermined variable in the storage unit 83 when the power is cut off, and it may be determined that it is the first startup based on whether the predetermined variable has the predetermined value when the power is turned on.

[0069] If it is the first startup after the power failure (S41: YES), the CPU 81 selects the first time constant as the time constant (S42) and ends the time constant recovery process. If it is not the first startup after the power failure (S41: NO), the CPU 81 ends the time constant recovery process.

[0070] If the second time constant is selected as the time constant after a power outage (see S23), the time constant at startup is the second time constant. The time constant can be restored to the first time constant by the time constant restoration process. If the acceleration / deceleration process is continued after the power outage (see S30), the time constant is the first time constant, so there is no need to execute the time constant restoration process.

[0071] In the machine tool according to the first embodiment, a first time constant is used for accelerating and decelerating the tool magazine 7a when there is no power outage, and a second time constant shorter than the first time constant is used when there is a power outage. The machine tool shortens the time required to sufficiently slow down the speed of the tool magazine 7a, and can suppress the load acting on the transmission mechanism of the tool magazine 7a when braking.

[0072] Furthermore, after a power outage, the deceleration process of the tool magazine 7a can be completed before the power stored in the power storage unit 87 runs out.

[0073] Furthermore, when power is restored after a power outage, the time constant used in the acceleration / deceleration process (see FIG. 6) is returned from the second time constant to the first time constant, and appropriate acceleration / deceleration process is performed. Furthermore, the machine tool can perform appropriate deceleration process in the event of a power outage depending on the respective states of constant speed rotation, acceleration, and deceleration. The CPU 81 that executes S4 corresponds to the power outage determination section. The CPU 81 that executes S6 corresponds to the acceleration / deceleration section. The CPU 81 that executes S22 and the CPU 81 that executes S42 and S43 correspond to the selection section. The CPU 81 that executes S23 to S28 corresponds to the deceleration section.

[0074] (Embodiment 2) The present invention will be described below with reference to the drawings showing a machine tool according to a second embodiment. The tool magazine 7a stores heavy tools or standard tools that are lighter than heavy tools. After storing tools in the tool magazine 7a, the worker operates the operation unit 51 to store information about each stored tool in the memory unit 83. For example, a tool number that identifies a tool and information indicating a heavy tool or a standard tool are associated with each other and stored in the memory unit 83. A heavy tool is one that exceeds a predetermined weight, and a standard tool is one that is equal to or less than the predetermined weight.

[0075] The operator operates the operation unit 51 to store the second time constant of the heavy tool, i.e., the third time constant, in the memory unit 83, and the second time constant of the standard tool, i.e., the fourth time constant, in the memory unit 83. The third time constants are, for example, time constants T3a and T3b. T3a corresponds to T2a, and indicates the time constant required for the acceleration of the magazine motor 73 to change from 0 to Ab and then to 0 again (see FIG. 3). T3b corresponds to T2b, and indicates the time constant required for the acceleration of the magazine motor 73 to change from Ab to 0 and the time constant required for the acceleration to change from 0 to Ab (see FIG. 3).

[0076] The fourth time constants are, for example, time constants T4a and T4b. T4a corresponds to T2a and indicates the time constant until the acceleration of the magazine motor 73 changes from 0 to Ab and then back to 0 (see FIG. 3). T4b corresponds to T2b and indicates the time constant until the acceleration of the magazine motor 73 changes from Ab to 0 and the time constant until the acceleration changes from 0 to Ab (see FIG. 3). A standard tool is lighter than a heavy tool, and the acceleration of the standard tool is more likely to reach the target acceleration in a shorter time than that of a heavy tool. Therefore, T4a is shorter than T3a, and T4b is shorter than T3b.

[0077] When the tool magazine 7a contains at least one heavy tool, the control device 80 selects the third time constant to execute the deceleration process. When the tool magazine 7a does not contain at least one heavy tool, i.e., when all the tools contained in the tool magazine 7a are standard tools, the control device 80 selects the fourth time constant to execute the deceleration process.

[0078] Fig. 9 is a flowchart illustrating the deceleration process by the control device 80. In the flowchart of Fig. 9, steps S21, S22, and S24 to S34 are the same as those in Fig. 7, and therefore detailed explanations thereof will be omitted. Here, steps S50 to S52, which are different from Fig. 7, will be explained.

[0079] In step S22, if the time constant switching is enabled (S22: YES), the CPU 81 accesses the memory unit 83 and determines whether the tool magazine 7a stores at least one heavy tool (S50). If the tool magazine 7a stores at least one heavy tool (S50: YES), the CPU 81 selects the third time constant, i.e., the time constants T3a and T3b, as the time constants (S51), and proceeds to step S24.

[0080] If the tool magazine 7a does not store at least one heavy tool (S50: NO), that is, if all the tools stored in the tool magazine 7a are standard tools, the CPU 81 selects the fourth time constant, that is, the time constants T4a and T4b, as the time constants (S52), and proceeds to step S24. The CPU 81 determines whether all the tools stored in the tool magazine 7a are standard tools based on the contents stored in the memory unit 83. The CPU 81 that executes S50 corresponds to a storage determination unit.

[0081] The machine tool according to the second embodiment is provided with a second time constant for heavy tools, i.e., a third time constant, and a second time constant for standard tools, i.e., a fourth time constant, as second time constants to be used during a power outage. When the tool magazine 7a stores heavy tools, the third time constant is used, and when the tool magazine stores only standard tools, a fourth time constant shorter than the third time constant is used. When storing standard tools, the time required to sufficiently reduce the speed of the tool magazine is shorter than when storing heavy tools, so the fourth time constant shorter than the third time constant is used, and the tool magazine 7a can be decelerated in a shorter time. The CPU 81 that executes S51, S52, and S24 to S28 corresponds to a deceleration section.

[0082] In step S50, it is determined whether the tool magazine 7a stores at least one heavy tool, but it may also be determined whether the tool magazine 7a stores at least two or three heavy tools, and the determination criteria can be changed as appropriate.

[0083] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims. [Explanation of symbols]

[0084] 7a Tool Magazine 71 Drive circuit 73 Magazine motor 73a Braking part 74 Encoder 80 Control device

Claims

1. A control device for a machine tool having a tool magazine for storing a plurality of tools, A power outage determination unit that determines whether or not a power outage has occurred; an acceleration / deceleration unit that accelerates or decelerates the tool magazine with a first time constant when the power failure determination unit determines that there is no power failure; a deceleration unit that decelerates the tool magazine with a second time constant that is shorter than the first time constant when the power outage determination unit determines that a power outage has occurred; Equipped Control device.

2. The tools include a heavy tool and a standard tool that is lighter than the heavy tool, the second time constant includes a third time constant corresponding to the heavy tool and a fourth time constant corresponding to the standard tool and shorter than the third time constant, a storage determination unit that determines whether the tool magazine stores the heavy tool, When the storage determination unit determines that the tool magazine stores the heavy tool, the deceleration unit decelerates the tool magazine with the third time constant, When the storage determination unit determines that the tool magazine does not store the heavy tool, the deceleration unit decelerates the tool magazine with the fourth time constant. The control device according to claim 1 .

3. a power storage unit that stores power to be supplied to the tool magazine; The second time constant is based on a time during which the tool magazine can be controlled by the power stored in the power storage unit. The control device according to claim 1 or 2.

4. A selection unit for selecting the first time constant or the second time constant, When the power outage determination unit determines that a power outage has occurred, the selection unit selects the second time constant, The deceleration unit decelerates the tool magazine at the second time constant selected by the selection unit, When power is restored after a power outage, the selection unit selects the temporary constant. A control device according to any one of claims 1 to 3.

5. When the power failure determination unit determines that a power failure has occurred while the tool magazine is rotating at a constant speed, accelerating, or decelerating, the selection unit selects the second time constant. The control device according to claim 4.

6. A tool magazine for storing a plurality of tools; A power outage determination unit that determines whether or not a power outage has occurred; an acceleration / deceleration unit that accelerates or decelerates the tool magazine with a first time constant when the power failure determination unit determines that there is no power failure; a deceleration unit that decelerates the tool magazine with a second time constant that is shorter than the first time constant when the power outage determination unit determines that a power outage has occurred; Equipped Machine tools.

7. A method for controlling a machine tool having a tool magazine that stores a plurality of tools, comprising: Determine whether there is a power outage, When it is determined that there is no power outage, the tool magazine is accelerated or decelerated with a first time constant; When it is determined that a power outage has occurred, the tool magazine is decelerated with a second time constant that is shorter than the first time constant. Control methods.

8. A computer program executed by a control device of a machine tool having a tool magazine that stores a plurality of tools, The control device includes: Determine whether there is a power outage, When it is determined that there is no power outage, the tool magazine is accelerated or decelerated with a first time constant; When it is determined that a power outage has occurred, the tool magazine is decelerated with a second time constant that is shorter than the first time constant. A computer program that executes a process.

Images