Working machinery

Abstract

To provide a machine tool that is configured to monitor a plurality of current values inputted to a plurality of motors, so as to be able to detect an abnormality occurring therein.SOLUTION: The machine tool is provided with: a current detecting part that detects a plurality of current values inputted to a first servo motor and to a second servo motor; a memorizing part that memorizes time-series variations of the plurality of current values at a normal time which are inputted to the first servo motor and the second servo motor, in a predetermined step of a series of tool exchanging steps which are performed between a rotary tool device and an automatic tool exchange device; and a determining part that determines whether the predetermined step is performed normally, by comparing the plurality of current values detected by the current detecting part with the time-series variations of the plurality of current values at a normal time, in the predetermined step.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a machine tool. [Background technology]

[0002] Generally, there is known a machine tool that includes a rotary tool device that rotatably holds a tool for machining a workpiece, and an automatic tool changer (ATC) that exchanges tools between the rotary tool device and the ATC. The machine tool uses, for example, a method described in Patent Document 1 to determine whether an abnormality such as a device failure or a collision has occurred in a series of tool exchange processes that are carried out between the rotary tool device and the ATC, and stops operation when an abnormality has occurred.

[0003] The method described in Patent Document 1 monitors the current value of one motor during a tool change operation, and stops the operation of the machine tool if the current value of this motor exceeds an allowable value. However, there are cases where multiple motors are used in a series of tool change processes, and by monitoring the multiple current values ​​input to these motors, it is possible to detect an abnormal state in the machine tool. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-246568 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a machine tool that is capable of detecting an abnormality occurring inside by monitoring a plurality of current values ​​input to a plurality of motors. [Means for solving the problem]

[0006] A machine tool according to an embodiment of the present disclosure is a machine tool comprising a rotary tool device and an automatic tool changer that changes tools between the rotary tool device and the rotary tool device, wherein the rotary tool device has (i) a rotary tool main body that rotatably holds a tool for machining a workpiece, and (ii) a first servo motor that generates power for operating the rotary tool device, and the automatic tool changer has a second servo motor that generates power for operating the automatic tool changer, and is also provided with a current detection unit that detects multiple current values ​​input to the first servo motor and the second servo motor, a memory unit that stores changes over time in multiple current values ​​input to the first servo motor and the second servo motor under normal conditions during a predetermined step of a series of tool changing steps performed between the rotary tool device and the automatic tool changer, and a determination unit that compares the multiple current values ​​detected by the current detection unit with the changes over time in multiple current values ​​under normal conditions during the predetermined step to determine whether the predetermined step is being performed normally.

[0007] In a machine tool according to an embodiment of the present disclosure, it is preferable that the automatic tool changer further includes a housing and a circular magazine housed within the housing and having a plurality of tool holding portions arranged along a circumferential direction for holding tools.

[0008] In a machine tool according to an embodiment of the present disclosure, it is preferable that the first servo motor generates power for operating a vertical movement mechanism that enables the rotary tool main body to move in the vertical direction, the second servo motor generates power for operating a magazine rotation mechanism that enables the magazine to rotate along the rotation axis, and the predetermined process is a process of moving the tool to a predetermined position where the tool is changed between the rotary tool device and the automatic tool changer, or a process of moving the tool from the predetermined position between the rotary tool device and the automatic tool changer to its original position before the series of tool change processes were started.

[0009] In a machine tool according to an embodiment of the present disclosure, it is preferable that the magazine has a fastener for holding one tool, and the judgment unit judges whether the fastener is damaged based on the current value input to the second servo motor detected by the current detection unit.

[0010] In a machine tool according to an embodiment of the present disclosure, it is preferable that the rotary tool device has a third servo motor that generates power to operate a first horizontal movement mechanism that enables the rotary tool main body to move along the horizontal direction, the current detection unit detects a current value input to the third servo motor, and the determination unit determines that another predetermined process is not being performed normally when the current value detected by the current detection unit does not change in another predetermined process among the series of tool changing processes performed between the rotary tool device and the automatic tool changer.

[0011] In a machine tool according to an embodiment of the present disclosure, it is preferable that the automatic tool changer has a fourth servo motor that generates power to operate a second horizontal movement mechanism that enables the housing to move horizontally, the current detection unit detects the current value input to the fourth servo motor, and the judgment unit judges that another specified process among the series of tool change processes performed between the rotary tool device and the automatic tool changer is not being performed normally if the current value detected by the current detection unit does not change in the other specified process.

[0012] In a machine tool according to an embodiment of the present disclosure, the other specified process is preferably a process of transferring a tool from a rotary tool device to an automatic tool changer, or a process of transferring a tool from the automatic tool changer to a rotary tool device. [Effects of the Invention]

[0013] According to the machine tool according to the embodiment of the present disclosure, it is possible to detect an abnormality occurring inside by monitoring a plurality of current values ​​input to a plurality of motors. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a partial perspective view of a machine tool according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the configuration of the machine tool shown in FIG. [Figure 3]FIG. 3 is an enlarged perspective view of the automatic tool changer shown in FIGS. 1 and 2. [Figure 4A] FIG. 4 is a front view of the magazine as seen from the viewpoint β shown in FIG. 3. [Figure 4B] FIG. 4B is a diagram (part 1) for explaining a process of holding tools in the magazine shown in FIG. 4A. [Figure 4C] FIG. 4B is a diagram (part 2) for explaining the process of holding tools in the magazine shown in FIG. 4A. [Figure 5] 4 is a flowchart showing a series of tool changing steps performed between the B-axis rotary tool device and the automatic tool changer of the machine tool according to the present embodiment. [Figure 6A] 6 is a diagram (part 1) showing the movement positions of the B-axis rotary tool device and the ATC in each step of the tool changing process shown in FIG. 5. FIG. [Figure 6B] 6 is a diagram (part 2) showing the movement positions of the B-axis rotary tool device and the ATC in each step of the tool changing process shown in FIG. 5. FIG. [Figure 6C] 6 is a diagram (part 3) showing the movement positions of the B-axis rotary tool device and the ATC in each step of the tool changing process shown in FIG. 5. FIG. [Figure 6D] 6 is a diagram (part 4) showing the movement positions of the B-axis rotary tool device and the ATC in each step of the tool changing process shown in FIG. 5. FIG. [Figure 6E] 6 is a diagram (part 5) showing the movement positions of the B-axis rotary tool device and the ATC in each step of the tool changing process shown in FIG. 5. FIG. [Figure 6F] 6 is a diagram (part 6) showing the movement positions of the B-axis rotary tool device and the ATC in each step of the tool changing process shown in FIG. 5. FIG. [Figure 7] 6 is a diagram showing waveforms of currents supplied to the servo motors under normal conditions in the series of tool replacement steps shown in FIG. 5. FIG. [Figure 8] FIG. 10 is a diagram showing waveforms of currents supplied to each servo motor in a predetermined tool changing process when an abnormality occurs in tool unclamping. [Figure 9]FIG. 10 is a diagram showing the waveform of a current supplied to each servo motor in a predetermined tool changing process when the next tool clamp is abnormal. [Figure 10] FIG. 10 is a diagram showing the waveform of a current supplied to each servo motor in a predetermined tool changing process when the magazine is damaged. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a machine tool according to the present embodiment will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiments, but extends to the inventions set forth in the claims and their equivalents.

[0016] Fig. 1 is a partial perspective view of a machine tool 1 according to this embodiment. The machine tool 1 shown in Fig. 1 is a device for machining a workpiece W, which is a long, round bar material. The machine tool 1 includes a spindle 2 for supporting the workpiece W, a rotary tool driving device 13 including a B-axis rotary tool device 3, etc., an automatic tool changer (ATC) 4, and a numerically controlled (NC) device 5, which will be described later, etc.

[0017] The spindle 2 is mounted on a support table 6. The spindle 2 supports the workpiece W rotatably around the Z axis, with the Z axis direction as its axis, and also supports the workpiece W movably to the front side of the support table 6. The support table 6 is fixedly supported by a bed 7.

[0018] A rail 8 extending along the X-axis direction (also referred to as the horizontal direction) perpendicular to the Z-axis direction is installed on the front side of the support base 6. A base 10 is attached to the rail 8 and slides in the direction of arrow α1 using power generated by a third servo motor MT3. A rail 11 extending along the Y-axis direction (also referred to as the vertical direction) perpendicular to the Z-axis and X-axis directions is installed on the base 10. A rotary tool driving device 13 is attached to the rail 11 and slides in the direction of arrow α2 using power generated by a first servo motor MT1.

[0019] The rotary tool driving device 13 is a device that holds tools for machining the workpiece W. The rotary tool driving device 13 has a B-axis rotary tool device 3 that has tools 131, 132, and a first tool 31 and a second tool 32. The tools 131, 132 are arranged side by side along the X-axis direction with their tips facing downward. The first tool 31 and the second tool 32 are rotatably held by a B-axis rotary tool main body 33 that constitutes the B-axis rotary tool device 3, and with their tips facing sideways, Y-axis direction The machine tool 1 according to this embodiment can machine the workpiece W with a predetermined tool by moving the workpiece W in the Z-axis direction using the spindle 2 and moving the rotary tool driving device 13 in the direction of arrow α1 or arrow α2. The B-axis rotary tool main body 33 is supported so as to be rotatable in the direction of arrow α0 around the rotation axis A of the rotation motor MT5 by power generated by the rotation motor MT5.

[0020] The ATC4 is a device that exchanges tools with the B-axis rotary tool device 3. The ATC4 includes a housing 41, a fourth servo motor MT4, a circular magazine 42 (described later) held in the housing 41, and a second servo motor MT2. A rail 15 extending along the X-axis direction is installed on the bed 7. The housing 41 is mounted on the rail 15 and slides in the direction of arrow α3 by power generated by the fourth servo motor MT4. The magazine 42 is supported rotatably in the direction of arrow α4 around the rotation axis B by power generated by the second servo motor MT2.

[0021] Fig. 2 is a block diagram showing the internal configuration of the machine tool 1 shown in Fig. 1. As shown in Fig. 2, the B-axis rotary tool device 3 includes a B-axis rotary tool main body 33, a first horizontal movement mechanism M3, a third servo motor MT3, a vertical movement mechanism M1, a first servo motor MT1, a turning mechanism M5, and a turning motor MT5.

[0022] The first horizontal movement mechanism M3 can move the entire rotary tool driving device 13, including the B-axis rotary tool main body 33, in the direction of arrow α1. The third servo motor MT3 converts input current into mechanical output (power such as torque and rotation speed) and supplies it to the first horizontal movement mechanism M3. This causes the first horizontal movement mechanism M3 to move the B-axis rotary tool main body 33 back and forth in the direction of arrow α1. The operation of the third servo motor MT3 is controlled by a motion controller C3.

[0023] The motion controller C3 inputs a predetermined current to the third servo motor MT3 in response to a control signal transmitted from the NC device 5 (described later). The control signal transmitted to the motion controller C3 includes at least the rotation amount (rad or number of steps) and rotation speed (rpm) of the third servo motor MT3. The third servo motor MT3 is provided with a sensor Se3, which detects the actual rotation amount and rotation speed of the third servo motor MT3 and transmits them to the motion controller C3. The motion controller C3 compares the rotation amount and rotation speed values ​​of the third servo motor MT3 included in the control signal with the actual rotation amount and rotation speed values ​​of the third servo motor MT3 detected by the sensor Se3, and inputs a predetermined current to the third servo motor MT3 so as to eliminate any deviation between these values. Hereinafter, the control methods of the motion controllers C1, C2, C4, and C5 are the same as those of the motion controller C3, and therefore detailed description thereof will be omitted.

[0024] The vertical movement mechanism M1 enables the entire rotary tool driving device 13, including the B-axis rotary tool main body 33, to move up and down in the direction of arrow α2. The first servo motor MT1 generates power for operating the vertical movement mechanism M1. The operation of the first servo motor MT1 is controlled by a motion controller C1. The method of controlling the first servo motor MT1 by the motion controller C1 is the same as the method of controlling the third servo motor MT3 by the motion controller C3, so a detailed description will be omitted.

[0025] The turning mechanism M5 can turn the B-axis rotary tool main body 33 in the direction of arrow α0 around the turning axis A of the turning motor MT5. The turning motor MT5 generates power for operating the turning mechanism M5. The operation of the turning motor MT5 is controlled by the motion controller C5. The method of controlling the turning motor MT5 by the motion controller C5 is the same as the method of controlling the third servo motor MT3 by the motion controller C3, so a detailed description will be omitted.

[0026] As shown in FIG. 2, the ATC 4 includes a circular magazine 42, a second horizontal movement mechanism M4, a fourth servo motor MT4, a magazine rotation mechanism M2, and a second servo motor MT2.

[0027] The second horizontal movement mechanism M4 is capable of moving the housing 41, which houses the magazine 42, in the direction of arrow α3. The fourth servo motor MT4 generates power for operating the second horizontal movement mechanism M4. The fourth servo motor MT4 converts an input current into a mechanical output (power such as torque and rotation speed) and supplies it to the second horizontal movement mechanism M4. This causes the second horizontal movement mechanism M4 to move the housing 41, which houses the magazine 42, back and forth in the direction of arrow α3. The operation of the fourth servo motor MT4 is controlled by a motion controller C4. The method of controlling the fourth servo motor MT4 by the motion controller C4 is the same as the method of controlling the third servo motor MT3 by the motion controller C3, so a detailed description will be omitted.

[0028] The magazine rotation mechanism M2 is capable of rotating the magazine 42 in the direction of arrow α4 around the rotation axis B. The second servo motor MT2 generates power for operating the magazine rotation mechanism M2. The second servo motor MT2 converts an input current into a mechanical output (power such as torque and rotation speed) and supplies it to the magazine rotation mechanism M2. This causes the magazine rotation mechanism M2 to rotate the magazine 42 in the direction of arrow α4 around the rotation axis B. The operation of the second servo motor MT2 is controlled by a motion controller C2. The method of controlling the second servo motor MT2 by the motion controller C2 is the same as the method of controlling the third servo motor MT3 by the motion controller C3, so a detailed description will be omitted.

[0029] The NC device 5 is a device for controlling the operation of each of the B-axis rotary tool device 3 and the ATC 4. As shown in FIG. 2, the NC device 5 is configured to include an interface unit 51, a memory unit 52, an input unit 53, an output unit 54, a current detection unit 55, and a control unit 56. The interface unit 51, the memory unit 52, the input unit 53, the output unit 54, the current detection unit 55, and the control unit 56 are connected to one another via a bus 57. Various control signals from the control unit 56 are transmitted to the motion controllers C1 to C5 via the interface unit 51. A plurality of current values ​​output from the motion controllers C1 to C5 to the corresponding servo motors MT1 to MT5 are transmitted to the current detection unit 55 via the interface unit 51.

[0030] The storage unit 52 includes, for example, a semiconductor storage device, and stores programs, data, and the like used in processing by the control unit 56. The storage unit 52 stores at least a program for causing the control unit 56 to execute a series of tool changing processes performed between the B-axis rotary tool device 3 and the ATC 4. The program may be installed into the storage unit 52 from a computer-readable portable recording medium such as a CD-ROM using a known setup program, etc. The storage unit 52 also stores in advance changes over time in the values ​​of multiple currents input to the servo motors MT1 to MT4 when the series of tool changing processes are performed normally.

[0031] Input unit 53 may be any device that can input data, and generates a signal corresponding to an operation by an operator of machine tool 1. The generated signal is supplied to control unit 56 as an instruction from the operator.

[0032] The output unit 54 may be any device capable of displaying video, images, etc., and displays video corresponding to video data supplied from the control unit 56, images corresponding to image data, etc.

[0033] The current detection unit 55 detects the values ​​of a plurality of currents input to the servo motors MT1 to MT4, and transmits the detection results to the control unit .

[0034] The control unit 56 comprehensively controls the overall operation of the machine tool 1 and is, for example, a CPU (Central Processing Unit). The control unit 56 executes a series of tool changing processes in accordance with a program stored in the memory unit 52. The control unit 56 has a command unit 561 and a determination unit 562. The command unit 561 transmits, for example, control signals for executing the series of tool changing processes to the motion controllers C1 to C5 via the interface unit 51. The control signals include the rotation amount (rad or number of steps) and rotation speed (rpm) of each servo motor. The determination unit 562 determines whether the series of tool changing processes are being performed normally. A specific determination procedure will be described later.

[0035] 3 is an enlarged perspective view of the ATC4 shown in FIGS. 1 and 2. As shown in FIG. 3, a magazine 42 is housed in a housing 41 of the ATC 4, and one end of a rotating shaft 43 constituting a magazine rotation mechanism M2 is fixedly supported at the center of the magazine 42. The rotating shaft 43 is rotatably supported by a support member 44 installed on a base 45. The magazine 42 rotates in the direction of arrow α4 by power generated by a second servo motor MT2. In addition, a shutter 46 is disposed in the housing 41. The shutter 46 is opened and closed by an opening / closing mechanism (not shown) to load and unload replacement tools housed in the ATC 4.

[0036] FIG. 4A is a front view of the magazine 42 as seen from viewpoint β shown in FIG. 3. As shown in FIG. 4A, the magazine 42 has twelve tool holders H1 to H12 arranged along the circumferential direction to hold tools. The tool holders H1 to H12 have the same configuration, and therefore, for the sake of convenience, only tool holder H1 will be described below. Each tool holder H1 has a recess H13 that stores a tool T and two fasteners H14 that have elastic members that grip the tool T stored in the recess H13. For example, as shown in FIG. 4B, the tool T is stored in the recess H13 by descending along the Y-axis direction, and is then elastically held in the recess H13 by the fasteners H14, as shown in FIG. 4C.

[0037] Fig. 5 is a flowchart showing a series of tool changing steps performed between the B-axis rotary tool device 3 and the ATC 4 of the machine tool 1 according to this embodiment. Figs. 6A to 6F are diagrams showing the movement positions of the B-axis rotary tool device 3 and the ATC 4 in each step of the series of tool changing steps shown in Fig. 5. Below, a normal operation when the second tool 32 held in the B-axis rotary tool main body 33 is changed to another tool will be described.

[0038] When a tool change command is input according to a predetermined procedure, the control unit 56 first executes the B-axis rotary tool device rotation in accordance with the program stored in the storage unit 52 (step S1). Specifically, the command unit 561 of the control unit 56 transmits predetermined control signals (the rotation amount (rad or number of steps) and rotation speed (rpm) of each servo motor) to the motion controller C3 via the interface unit 51. In response to the control signal transmitted from the command unit 561, the motion controller C3 controls the third servo motor MT3 to drive the first horizontal movement mechanism M3, thereby moving the B-axis rotary tool device 3 and moving the B-axis rotary tool main body 33 along the rail 8 in the direction of arrow α1 (forward direction) shown in FIG. 6A. For convenience, a description of the movement mechanisms M1 to M5 and the B-axis rotary tool device 3 will be omitted below. Also, the description of the transmission of control signals from the command unit 561 to the motion controllers C1 to C5, and the control of the servo motors MT1 to MT4 and the swing motor MT5 in accordance with the control signals in the motion controllers C1 to C5 will be omitted.

[0039] Next, the command unit 561 controls the turning motor MT5 to turn the B-axis rotary tool main body 33 180 degrees in the direction of the arrow α0 shown in FIG. 6A around the turning axis A of the turning motor MT5.

[0040] Next, the control unit 56 executes horizontal movement of the B-axis rotary tool device 3 and the ATC 4 (step S2). Specifically, as shown in FIG. 6A, the command unit 561 of the control unit 56 controls the third servo motor MT3 to move the B-axis rotary tool main body 33 in the direction of arrow α1 (forward direction), and at the same time, the command unit 561 of the control unit 56 controls the fourth servo motor MT4 to move the housing 41 in the direction of arrow α3 (forward direction). At this time, the shutter 46 of the housing 41 is opened by an opening / closing mechanism (not shown). As a result, the B-axis rotary tool main body 33 and the housing 41 move from the state shown in FIG. 6A to the state shown in FIG. 6B.

[0041] Next, the control unit 56 executes vertical movement of the B-axis rotary tool device 3 (step S3). Specifically, as shown in Fig. 6B, the command unit 561 of the control unit 56 controls the first servo motor MT1 to lower the B-axis rotary tool main body 33 in the direction of arrow α2. As the B-axis rotary tool main body 33 lowers, the second tool 32 supported by the B-axis rotary tool main body 33 is temporarily held by the two fasteners H14 of the vacant tool holder H1.

[0042] Before the B-axis rotary tool main body 33 descends, the command unit 561 of the control unit 56 controls the second servo motor MT2 to rotate the magazine 42 so that the vacant tool holder H1 is positioned directly below the second tool 32. Furthermore, from the time the B-axis rotary tool main body 33 descends until the start of the next step, the command unit 561 controls the second servo motor MT2 to maintain the magazine 42 at a predetermined position so as not to rotate.

[0043] Next, the control unit 56 executes tool unclamping (step S4). Specifically, the command unit 561 of the control unit 56 controls a tool holding mechanism (not shown) that holds the second tool 32 in the B-axis rotary tool main body 33 to release the second tool 32. Furthermore, the command unit 561 of the control unit 56 controls the third servo motor MT3 to slightly move the B-axis rotary tool main body 33 in the direction of arrow α1 (forward direction) while the second tool 32 remains temporarily held in the tool holder H1. As a result, the B-axis rotary tool main body 33 pushes the magazine 42 through the second tool 32, and the second tool 32 is released from the B-axis rotary tool main body 33 and is completely held in the tool holder H1. That is, step S4 completes the transfer of the second tool 32 from the B-axis rotary tool device 3 to the ATC 4. This state is shown in FIG. 6C.

[0044] When the B-axis rotary tool main body 33 pushes in the magazine 42, a load is generated by the magazine 42. Therefore, the current value supplied from the motion controller C3 to the third servo motor MT3, which is controlled to move the B-axis rotary tool main body 33 in the direction of the arrow α1, varies compared to when there is no load from the magazine 42.

[0045] On the other hand, the command unit 561 of the control unit 56 controls the fourth servo motor MT4 to maintain the housing 41 at a predetermined position (the position shown in FIG. 6C). However, since the magazine 42 is pushed in by the B-axis rotary tool main body 33 via the second tool 32, the current value output from the motion controller C4 to the fourth servo motor MT4 fluctuates in an attempt to maintain the housing 41 at the predetermined position compared to when the housing 41 is not pushed in.

[0046] Next, the control unit 56 executes horizontal movement of the B-axis rotary tool device 3 (step S5). Specifically, as shown in Fig. 6C, the command unit 561 of the control unit 56 controls the third servo motor MT3 to move the B-axis rotary tool main body 33 in the direction of arrow α1 (rearward direction). As a result, the B-axis rotary tool main body 33 moves from the state shown in Fig. 6C to the state shown in Fig. 6D.

[0047] Next, the control unit 56 executes preparation for the next tool (step S6). Specifically, the command unit 561 controls the second servo motor MT2 to rotate the magazine 42 in the direction of the arrow α4 around the rotation axis B so that the tool holder Hn holding the next tool to be used (next tool 321) is positioned at the top. This state is shown in FIG. 6D.

[0048] Next, the control unit 56 executes horizontal movement of the B-axis rotary tool device 3 (step S7). Specifically, as shown in Fig. 6D, the command unit 561 of the control unit 56 controls the third servo motor MT3 to move the B-axis rotary tool main body 33 in the direction of arrow α1 (forward direction).

[0049] Next, the control unit 56 executes clamping of the next tool (step S8). Specifically, the command unit 561 of the control unit 56 controls the third servo motor MT3 to slightly move the B-axis rotary tool main body 33 in the direction of arrow α1 (forward direction), while controlling the tool holding mechanism in the B-axis rotary tool main body 33 to hold the next tool 321. That is, step S8 completes the transfer of the next tool 321 from the ATC 4 to the B-axis rotary tool device 3. This state is shown in FIG. 6E.

[0050] When the next tool 321 is held in step S8, the B-axis rotary tool main body 33 ends up pushing the magazine 42 through the next tool 321. Therefore, the value of the current supplied from the motion controller C3 to the third servo motor MT3, which is controlled to move the B-axis rotary tool main body 33 in the direction of arrow α1, is higher than when there is no load from the magazine 42. Similarly, because the magazine 42 is pushed in by the B-axis rotary tool main body 33 through the next tool 321, the value of the current output from the motion controller C4 to the fourth servo motor MT4 is higher than when the housing 41 is not pushed in, in an attempt to maintain the housing 41 in a predetermined position.

[0051] Next, the control unit 56 executes vertical movement of the B-axis rotary tool device 3 (step S9). As shown in FIG. 6E, the command unit 561 of the control unit 56 controls the first servo motor MT1 to lift the B-axis rotary tool main body 33 in the direction of arrow α2. As a result, the B-axis rotary tool main body 33 moves from the state shown in FIG. 6E to the state shown in FIG. 6F. In this state, the next tool 321 is removed from the magazine 42. Furthermore, from the time the B-axis rotary tool main body 33 is lifted until the start of the next step, the command unit 561 of the control unit 56 controls the second servo motor MT2 to maintain the magazine 42 at a predetermined position so as not to rotate.

[0052] Next, the control unit 56 executes horizontal movement of the B-axis rotary tool device 3 and the ATC 4 (step S10). Specifically, as shown in Fig. 6F, the command unit 561 of the control unit 56 controls the third servo motor MT3 to move the B-axis rotary tool main body 33 in the direction of arrow α1 (rearward direction), and at the same time, the command unit 561 of the control unit 56 controls the fourth servo motor MT4 to move the casing 41 in the direction of arrow α3 (rearward direction). At this time, the shutter 46 of the casing 41 is closed by an opening / closing mechanism (not shown).

[0053] Finally, the control unit 56 executes the B-axis rotary tool device pivoting (step S11), thereby completing the tool replacement process. Specifically, the command unit 561 of the control unit 56 controls the pivot motor MT5 to pivot the B-axis rotary tool main body 33 180 degrees around the pivot axis A of the pivot motor MT5 in the direction of the arrow α0 shown in FIG. 6F. At the same time, the command unit 561 of the control unit 56 controls the third servo motor MT3 to move the B-axis rotary tool main body 33 in the direction of the arrow α1 shown in FIG. 6F (the backward direction). As a result, the B-axis rotary tool main body 33 moves from the state shown in FIG. 6F back to the state shown in FIG. 6A.

[0054] FIG. 7 shows the waveforms of currents normally supplied to each servo motor during a series of tool change processes. In FIG. 7, the horizontal axis represents time (times t1 to t8) (s), the vertical axis represents current value (mA), and S3 to S9 represent periods corresponding to steps in the series of tool change processes shown in FIG. 5. Current A1 represents the waveform of the current supplied from motion controller C1 to first servo motor MT1, and current A2 represents the waveform of the current supplied from motion controller C2 to second servo motor MT2. Current A3 represents the waveform of the current supplied from motion controller C3 to third servo motor MT3, and current A4 represents the waveform of the current supplied from motion controller C4 to fourth servo motor MT4. The same applies to FIGS. 8 to 10.

[0055] 7, as described for step S4 in Fig. 5, when the magazine 42 is pushed in by the B-axis rotary tool main body 33, the value of the current supplied from the motion controller C3 to the third servo motor MT3 fluctuates due to the load caused by the magazine 42. During the period of current A3 shown as P2 in Fig. 7, as described for step S8 in Fig. 5, when the magazine 42 is pushed in by the B-axis rotary tool main body 33, the value of the current supplied from the motion controller C3 to the third servo motor MT3 fluctuates due to the load caused by the magazine 42.

[0056] 7, as described for step S4 in Fig. 5, when the magazine 42 is pushed in by the B-axis rotary tool main body 33, the value of the current supplied from the motion controller C4 to the fourth servo motor MT4 fluctuates in order to maintain the position of the casing 41 against the pushing by the B-axis rotary tool main body 33. As described for step S8 in Fig. 5, when the magazine 42 is pushed in by the B-axis rotary tool main body 33, the value of the current supplied from the motion controller C4 to the fourth servo motor MT4 fluctuates in order to maintain the position of the casing 41 against the pushing by the B-axis rotary tool main body.

[0057] During the period of current A2 shown as P5 in Fig. 7, the value of the current supplied from the motion controller C2 to the second servo motor MT2 does not fluctuate during normal operation of step S3 in Fig. 5, because no phenomenon occurs that would move the magazine 42. During the period of current A2 shown as P6 in Fig. 7, the value of the current supplied from the motion controller C2 to the second servo motor MT2 does not fluctuate during normal operation of step S9 in Fig. 5, because no phenomenon occurs that would move the magazine 42.

[0058] During the period of current A1 shown as P7 in Fig. 7, the B-axis rotary tool main body 33 is lowered, and therefore the value of the current supplied from the motion controller C1 to the first servo motor MT1 fluctuates, as described for the normal operation of step S3 in Fig. 5. During the period of current A1 shown as P8 in Fig. 7, the B-axis rotary tool main body 33 is raised, and therefore the value of the current supplied from the motion controller C1 to the first servo motor MT1 fluctuates, as described for the normal operation of step S9 in Fig. 5.

[0059] FIG. 8 shows the waveform of the current supplied to each servo motor in a predetermined tool changing process (see step S4 in FIG. 5) when an abnormality occurs in the tool unclamping.

[0060] For example, if the B-axis rotary tool main body 33 does not hold the second tool 32, the operation of step S4 in FIG. 5 does not cause the B-axis rotary tool main body 33 to push in the magazine 42. Therefore, during the period of current A3 indicated as P1' in FIG. 8, there is no load due to the magazine 42, and the value of the current supplied from the motion controller C3 to the third servo motor MT3 does not fluctuate. Similarly, during the period of current A3 indicated as P3' in FIG. 8, there is no pushing in of the magazine 42 by the B-axis rotary tool main body 33, and the value of the current supplied from the motion controller C4 to the fourth servo motor MT4 does not fluctuate. Note that the waveforms of current A3 and current A4 during normal operation are indicated by dashed lines at P1' and P3' in FIG. 8.

[0061] As shown in Fig. 8, by comparing the current waveform during normal operation (see Fig. 7) with the current waveform during abnormal operation (see Fig. 8), it is possible to detect an abnormality during tool unclamping. Specifically, the memory unit 52 stores in advance the current waveform during normal operation as shown in Fig. 7. After the tool replacement process starts, the current detection unit 55 detects the value of the current supplied to the third servo motor MT3 and / or the value of the current supplied to the fourth servo motor MT4, and if a predetermined current fluctuation does not occur during the period from time t2 to t3 corresponding to step S4, the determination unit 562 of the control unit 56 determines that an abnormality has occurred.

[0062] As described above, an abnormality does not necessarily occur only when the current value supplied to the servo motor exceeds the allowable value. Therefore, the machine tool 1 according to this embodiment can detect an abnormality that occurs internally during the process of performing tool unclamping, even if the motor current value is below the allowable value.

[0063] FIG. 9 shows the waveform of the current supplied to each servo motor in a predetermined tool changing process (see step S8 in FIG. 5) when the next tool clamp is abnormal.

[0064] For example, if the B-axis rotary tool main body 33 does not hold the next tool 321, the operation of step S8 in FIG. 5 does not cause the B-axis rotary tool main body 33 to push in the magazine 42. Therefore, during the period of current A3 indicated by P2' in FIG. 9, there is no load due to the magazine 42, and the value of the current supplied from the motion controller C3 to the third servo motor MT3 does not fluctuate. Similarly, during the period of current A3 indicated by P4' in FIG. 9, there is no pushing in of the magazine 42 by the B-axis rotary tool main body 33, and the value of the current supplied from the motion controller C4 to the fourth servo motor MT4 does not fluctuate. Note that at P2' and P4' in FIG. 9, the waveforms of current A3 and current A4 during normal operation are indicated by dashed lines.

[0065] As shown in Fig. 9, by comparing the current waveform during normal operation (see Fig. 7) with the current waveform during abnormal operation (see Fig. 9), it is possible to detect an abnormality when unclamping the next tool. Specifically, the memory unit 52 stores in advance the current waveform during normal operation as shown in Fig. 7. After the tool changing process starts, the current detection unit 55 detects the value of the current supplied to the third servo motor MT3 and / or the value of the current supplied to the fourth servo motor MT4, and if a predetermined current fluctuation does not occur during the period from time t6 to time t7 corresponding to step S8, the determination unit 562 of the control unit 56 determines that an abnormality has occurred.

[0066] As described above, an abnormality does not necessarily occur only when the current value supplied to the servo motor exceeds the allowable value. Therefore, the machine tool 1 according to this embodiment can detect an abnormality that occurs internally in the process of unclamping the next tool, even if the motor current value is below the allowable value.

[0067] FIG. 10 shows the waveform of the current supplied to each servo motor in a predetermined tool replacement process (see steps S3 and S9 in FIG. 5) when the magazine 42 is damaged.

[0068] 4A and 4B, the tool is stored in one of the tool holders H1 to H12, each having two fasteners H14, provided on the magazine 42. When inserting the tool into the tool holder (step S3) and when removing the tool from the tool holder (step S9), the motion controller C2 controls the second servo motor MT2 in response to instructions from the command unit 561 of the control unit 56, so as to maintain the magazine 42 at a predetermined position.

[0069] For example, it is conceivable that one of the two fasteners H14 may be damaged for some reason. In such a case, when an attempt is made to insert or remove a tool from the tool holding portion, a load is applied to the magazine 42, causing it to rotate in either the left or right direction. When a load is applied, the motion controller C2 varies the value of the current supplied to the second servo motor MT2 to control the magazine 42 so that it is maintained in a predetermined position.

[0070] When inserting a tool into the tool holder (step S3), during the period of current A2 indicated as P5' in FIG. 10, if the left fastener H14 of the two fasteners H14 shown in FIG. 4A is broken, the motion controller C2 increases the current value supplied to the second servo motor MT2 to restrict rotation of the magazine 42 toward the broken fastener H14, as shown in current waveform 60 in FIG. 10. On the other hand, if the right fastener H14 of the two fasteners H14 shown in FIG. 4A is broken, the motion controller C2 decreases the current value supplied to the second servo motor MT2 to restrict rotation of the magazine 42 toward the broken fastener H14, as shown in current waveform 61 in FIG. 10. Note that the waveform of current A2 during normal operation is indicated by a dashed line at P5 in FIG. 10.

[0071] Furthermore, when the tool is removed from the tool holding portion (step S9), during the period of current A2 indicated by P6' in FIG. 10, if the left fastener H14 of the two fasteners H14 shown in FIG. 4A is broken, the motion controller C2 increases the current value supplied to the second servo motor MT2 to restrict rotation of the magazine 42 toward the broken fastener H14, as shown by current waveform 62 in FIG. 10. On the other hand, if the right fastener H14 of the two fasteners H14 shown in FIG. 4A is broken, the motion controller C2 decreases the current value supplied to the second servo motor MT2 to restrict rotation of the magazine 42 toward the broken fastener H14, as shown by current waveform 63 in FIG. 10. Note that the waveform of current A2 during normal operation is indicated by a dashed line at P6' in FIG.

[0072] In response to an instruction from the command unit 561 of the control unit 56, the motion controller C1 controls the first servo motor MT1 to lower and raise the B-axis rotary tool main body 33. For example, if one of the two fasteners H14 is broken and an attempt is made to lower and raise the B-axis rotary tool main body 33, the elastic resistance of the fastener H14 will be smaller than the elastic resistance when the fastener H14 is not broken, and the load on the first servo motor MT1 will also be smaller. When the load becomes smaller, the motion controller C1 controls the current value supplied to the first servo motor MT1 to be smaller than normal.

[0073] When the tool is inserted into the tool holder (step S3), the elastic resistance of the fastener H14 is small during the period of current A1 shown as P7' in Fig. 10, so fluctuations in the value of the current supplied from the motion controller C1 to the first servo motor MT1 are small. Note that the waveform of current A1 during normal operation is shown by a dashed line at P7' in Fig. 10.

[0074] Furthermore, when the tool is removed from the tool holder (step S9), the elastic resistance of the fastener H14 is reduced during the period of current A1 shown as P8' in Fig. 10, so fluctuations in the value of the current supplied from the motion controller C1 to the first servo motor MT1 are reduced. Note that the waveform of current A1 during normal operation is shown by a dashed line at P8' in Fig. 10.

[0075] As shown in FIG. 10, by comparing the current waveform during normal operation (see FIG. 7) with the current waveform during abnormal operation (see FIG. 10), it is possible to detect an abnormality due to damage to the magazine 42. Specifically, the memory unit 52 pre-stores the current waveform during normal operation as shown in FIG. 7. After the tool replacement process starts, the current detection unit 55 detects the current values ​​of the current A1 supplied to the first servo motor MT1 and the current A2 supplied to the second servo motor MT2. If a predetermined current fluctuation occurs during the period from time t1 to t2 corresponding to step S3 and / or the period from time t7 to t8 corresponding to step S9, the determination unit 562 of the control unit 56 determines that an abnormality has occurred. In this way, when a phenomenon occurs in which multiple current waveforms simultaneously exhibit different waveforms for the same abnormality, comparing the time-dependent changes in the multiple current values ​​with normal values ​​allows for more accurate abnormality determination.

[0076] As described above in detail, the machine tool 1 according to this embodiment is capable of detecting the current value supplied to the associated servo motor to determine at least whether or not there is an abnormality when unclamping a tool, an abnormality when clamping the next tool, and / or an abnormality due to damage to the magazine 42.

[0077] Here, in the machine tool 1 according to this embodiment, the actual rotation amounts and actual rotation speeds of the servo motors MT1 to MT4 and the swing motor MT5 detected by the sensors Se1 to Se5 may also be transmitted to the NC device 5.

[0078] Furthermore, in the machine tool 1 according to this embodiment, the memory unit 52 may be configured to pre-store at least the changes over time in the multiple current values ​​input to the first servo motor MT1 and the second servo motor MT2 when a series of tool replacement processes are carried out normally.

[0079] Furthermore, in the machine tool 1 according to this embodiment, a plurality of first servo motors MT1 controlled by the motion controller C1 may be installed, and the B-axis rotary tool device 3 may operate the vertical movement mechanism M1 using a plurality of first servo motors MT1. Note that the same applies to the other motion controllers C2 to C5, the other servo motors MT2 to MT5, and the other mechanisms M2 to M5, and detailed description thereof will be omitted.

[0080] Furthermore, in step S1, the control unit 56 executes the B-axis rotary tool device turning by dividing the process into a process of moving the B-axis rotary tool main body 33 along the rail 8 in the direction of arrow α1 (forward direction) and a process of turning the B-axis rotary tool main body 33 180 degrees in the direction of arrow α0 around the turning axis A of the turning motor MT5. However, similar to step S11, in step S1, the control unit 56 may control the third servo motor MT3 to move the B-axis rotary tool main body 33 in the direction of arrow α1 (forward direction), and at the same time turn the B-axis rotary tool main body 33 180 degrees in the direction of arrow α0 around the turning axis A of the turning motor MT5.

[0081] 4A to 4C, each of the tool holding units H1 to H12 in the machine tool 1 according to this embodiment has two fasteners H14 having an elastic member for gripping a tool T. However, in the machine tool 1 according to this embodiment, the fasteners of the tool holding units H1 to H12 may be configured as a single unit.

[0082] Although the embodiments have been described above, all examples and conditions described herein are described for the purpose of helping to understand the concepts of the invention as applied to the invention and technology. The particularly described examples and conditions are not intended to limit the scope of the invention, and the construction of such examples in the specification does not indicate the advantages and disadvantages of the invention. Although the embodiments of the invention have been described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention. [Explanation of symbols]

[0083] 1 Machine tools 2 spindle 3 B-axis rotary tool device 4 Automatic tool changer (ATC) 5. Numerical control device (NC device) 32 2nd tool 33 B-axis rotary tool body 41 Case 42 Magazine 51 Interface section 52 Storage section 53 Input section 54 Output section 55 Current detection section 56 Control Unit 321 Next tool 561 Command Department 562 Judgment section MT1~MT4 1st servo motor~4th servo motor

Claims

1. A machine tool including a rotary tool device and an automatic tool changer that changes tools between the rotary tool device and the automatic tool changer, The rotary tool device is a rotary tool body portion that rotatably holds the tool in order to machine a workpiece, The automatic tool changer is a circular magazine having a plurality of tool holding portions arranged along a circumferential direction to hold the tools for replacing the tools; a magazine servomotor that generates power for operating a magazine rotation mechanism that enables the magazine to rotate along a rotation axis, a current detection unit that detects a magazine current value input to the magazine servo motor; a storage unit configured to store a change over time in a magazine current value input to the magazine servo motor under normal conditions in a step of transferring the tool from the rotary tool main body to the magazine or in a step of transferring the tool from the magazine to the rotary tool main body; a determination unit that compares the magazine current value detected by the current detection unit with a change over time in the magazine current value in the normal state and determines whether the transfer process is being performed normally; A machine tool comprising:

2. The automatic tool changer further includes a housing, the magazine housed in the housing, and a shutter that opens and closes when transferring the tool. The machine tool according to claim 1.

3. the magazine has a fastener for holding one of the tools; the determination unit determines whether the fastener is damaged based on a magazine current value input to the magazine servomotor detected by the current detection unit. The machine tool according to claim 1.

4. The machine tool according to claim 3 , wherein the determination unit determines whether or not there is an abnormality when the tool is unclamped or when a next tool is clamped.

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