Working machinery

Abstract

To provide a machine tool that allows setting the parameters of the spindle motor during spindle orientation. [Solution] The machine tool of this disclosure comprises a spindle to which a chuck mechanism for gripping a workpiece can be attached, a spindle motor for rotating the spindle, and a control device for controlling the rotation of the spindle motor. The control device performs a test operation to rotate the spindle by controlling the spindle motor, and sets parameters for controlling the spindle motor in spindle orientation based on a value related to the spindle inertia estimated from at least one of the magnitude of the driving torque of the spindle motor in the test operation and the time it takes for the spindle motor to reach the commanded speed.

Description

Technical Field

[0001] This disclosure relates to a technique for adjusting parameters of a spindle motor that rotates a spindle provided in a machine tool.

Background Art

[0002] The following Patent Document 1 describes a technique for adjusting parameters of a spindle motor. The adjustment system in Patent Document 1 uses a servo motor as the spindle motor. When an operator presses a parameter adjustment command button, the acceleration is calculated while restricting the motor torque of the servo motor by the motor torque control means. The adjustment system calculates the inertia of the spindle from the calculated acceleration and motor torque information and calculates the parameters.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described adjustment system, the parameters of the servo motor when rotating the spindle during workpiece machining are adjusted. However, in a machine tool, not only during workpiece machining, but also for so-called spindle orientation in which the spindle is rotated to a predetermined rotational position and stopped in order to avoid interference with other devices such as a loader and a sensor, it is necessary to adjust the parameters of the spindle motor. If the parameters for spindle orientation are not appropriate, there is a risk that the chuck mechanism will not stop at the desired rotational position.

[0005] This disclosure has been made in view of the above problems, and an object thereof is to provide a machine tool capable of setting parameters of a spindle motor in spindle orientation. [Means for solving the problem]

[0006] To solve the above problems, this specification discloses a machine tool comprising a spindle to which a chuck mechanism for gripping a workpiece can be attached, a spindle motor for rotating the spindle, and a control device for controlling the rotation of the spindle motor, wherein the control device performs a test operation to rotate the spindle by controlling the spindle motor, and sets parameters for controlling the spindle motor in spindle orientation based on a value relating to the spindle inertia estimated from at least one of the magnitude of the driving torque of the spindle motor in the test operation and the time to reach the commanded speed for the spindle motor. [Effects of the Invention]

[0007] According to the machine tool of this disclosure, when the chuck mechanism is changed in accordance with workpiece setup changes, the inertia value, which fluctuates according to the weight of the changed chuck mechanism, can be estimated by performing a test operation. Based on the estimated inertia value, the parameters for controlling the spindle motor in spindle orientation can be set to correspond to the weight of the chuck mechanism. The spindle orientation parameters can be changed to values ​​corresponding to the weight of the chuck mechanism, and spindle orientation can be performed appropriately. [Brief explanation of the drawing]

[0008] [Figure 1] A block diagram of a machine tool according to this embodiment. [Figure 2] A schematic diagram showing the arrangement of the workpiece spindle and turret equipment. [Figure 3] A flowchart of the parameter setting process. [Figure 4] A diagram showing the automatic spindle orientation adjustment screen. [Figure 5] A diagram showing the corresponding data. [Modes for carrying out the invention]

[0009] Hereinafter, an embodiment of the machine tool described herein will be described with reference to the drawings. Figure 1 shows a block diagram of the machine tool 10 of this embodiment. Figure 2 shows a schematic diagram of the workpiece spindle unit 12 and turret unit 13 arranged in the machining chamber of the machine tool 10. As shown in Figures 1 and 2, the machine tool 10 is, for example, a lathe and includes a bed 11, a workpiece spindle unit 12, a turret unit 13, a loader 14, a tool sensor 15, an operation panel 16, a control device 17, etc.

[0010] The bed 11 is, for example, a bed with a slant structure. The work spindle unit 12 is mounted on the bed 11. The work spindle unit 12 has a headstock 21 and a spindle motor 22. A spindle 23 (also called a main spindle) is rotatably mounted on the headstock 21. A pulley 25 is attached to the base end of the spindle 23. A pulley 26 is attached to the output shaft of the spindle motor 22. The pulleys 25 and 26 are connected by a belt 27. As a result, the spindle 23 receives the rotational driving force of the spindle motor 22 via the pulleys 25 and 26 and the belt 27, and rotates around a predetermined work spindle 28.

[0011] A chuck mechanism 31 is detachably attached to the tip of the spindle 23. The chuck mechanism 31 can be fitted with, for example, a plurality of chuck jaws 32. The plurality of chuck jaws 32 open and close in response to the drive of a drawbar (not shown) and a fluid pressure cylinder provided on the spindle head 21, switching between a chucked state in which the workpiece W is clamped and fixed, and an unchucked state in which the workpiece W is released from being clamped. The configuration of the chuck mechanism of this disclosure is not limited to the configuration in which the plurality of chuck jaws 32 described above are opened and closed, but other configurations such as a collet chuck can also be adopted.

[0012] The workpiece spindle device 12 rotates the workpiece W around the workpiece spindle 28 while the workpiece W is held in place by the chuck mechanism 31. Furthermore, the workpiece spindle device 12 can replace the chuck mechanism 31 with another chuck mechanism 31 depending on the type of workpiece W being machined. The operator changes the chuck mechanism 31 and chuck jaws 32 attached to the spindle 23 according to the type of workpiece W. Therefore, the weight of the chuck mechanism 31 and chuck jaws 32 attached to the spindle 23, as well as the weight of the workpiece W held by the chuck mechanism 31, vary depending on the type of workpiece W being machined.

[0013] The turret device 13 is equipped with a tool post 36 to which a cutting tool 35 (such as a cutting tool or rotary tool) can be attached, and a turret motor (not shown) for rotating the tool post 36. The turret device 13 performs machining on the workpiece W, which is held by the workpiece spindle device 12, using the cutting tool 35. The turret device 13 switches the cutting tool 35 used to machine the workpiece W by rotating the tool post 36. Note that in order to avoid complexity in the drawing, Figure 2 shows only one of the multiple cutting tools 35 that can be attached to the tool post 36.

[0014] Furthermore, the device used to process the workpiece W is not limited to a turret-type device. For example, the machine tool 10 may be equipped with a tool spindle (spindle head) that has one rotary tool as a processing device. The machine tool 10 may also be configured to include an ATC (automatic tool changer) that changes the rotary tool on the tool spindle. The machine tool 10 may also be equipped with multiple turret devices 13. The machine tool 10 may also be a multi-tasking machine equipped with a turret device 13 and a machining center.

[0015] The loader 14 is, for example, a gantry-type workpiece transfer device, and includes a head 38 having a chuck 37 for gripping the workpiece W, and a sliding mechanism 39 for sliding the head 38 in the X-axis direction and the Z-axis direction. The loader 14 transfers the workpiece W between the workpiece spindle device 12, the equipment for the preceding process, the equipment for the succeeding process, the inlet device, the outlet device, etc. Note that the device that transfers the workpiece W is not limited to a loader, but may be other devices such as an articulated robot.

[0016] The tool sensor 15 is, for example, a contact-type sensor used to measure the amount of wear on the cutting tool 35. For example, the tool sensor 15 is rotatable between the measurement position shown by the dashed line and the storage position shown by the solid line in Figure 2. When measuring the amount of wear, the machine tool 10 places the tool sensor 15 at the measurement position near the chuck mechanism 31, brings the tool post 36 of the turret device 13 closer to the workpiece spindle device 12, and brings the cutting edge (such as the tip of a chip) of the cutting tool 35 into contact with the tool sensor 15. The machine tool 10 measures the amount of wear on the cutting tool 35 from the position of the cutting tool 35 at the moment when the tool sensor 15 outputs a signal indicating that contact has been made with the cutting edge. When the machine tool 10 is not using the tool sensor 15, it rotates the tool sensor 15 to a storage position away from the chuck jaws 32 of the chuck mechanism 31. Furthermore, the machine tool 10 may be configured to rotate the tool sensor 15 and house the tool sensor 15 within the wall of the machining chamber.

[0017] Furthermore, when measuring the amount of wear, if the tool sensor 15 is placed at a measurement position near the chuck mechanism 31, there is a risk that the chuck 37 and the tool sensor 15 may interfere with each other depending on the rotation position of the chuck mechanism 31. For this reason, the machine tool 10 performs spindle orientation, rotating the chuck mechanism 31 (spindle 23) to a retracted position to avoid interference between the tool sensor 15 and the chuck jaws 32. After performing spindle orientation and rotating the spindle 23 to the retracted position and stopping it, the machine tool 10 places the tool sensor 15 at the measurement position described above to measure the amount of wear. In this spindle orientation, the machine tool 10 controls the spindle motor 22 using parameters set in the parameter setting process described later. Note that the tool sensor 15 is not the only device that may interfere with the chuck jaws 32, i.e., a device that requires spindle orientation for use. For example, a device that requires spindle orientation may be a measuring device (touch sensor) that measures the width of a groove formed on the outer circumference of the workpiece W. Therefore, before using such a measuring device, the machine tool 10 may perform spindle orientation using the parameters set by performing the parameter setting process described later.

[0018] Furthermore, the control panel 16 is the user interface for the machine tool 10 and is equipped with a touch panel 41, operation switches 43, etc. Based on the control of the control device 17, the control panel 16 displays information related to the machine tool 10 on the touch panel 41. The control panel 16 also accepts user input on the screen displayed on the touch panel 41 and outputs a signal to the control device 17 corresponding to the received input. Note that the above-described user interface configuration is just an example. For example, the user interface may consist only of a touch panel 41, or it may not have a touch panel 41 but consist of operation switches 43 and a monitor (such as an LCD monitor).

[0019] As shown in FIG. 1, the control device 17 includes a numerical control device 51 and a PLC 52. The numerical control device 51 includes a CPU 54 and a storage device 55. The storage device 55 includes, for example, a RAM, a ROM, a flash memory, an HDD, etc. The storage device 55 can store an NC program 56, a control program 57, and corresponding data 58. Note that the configuration of the storage device 55 for storing the NC program 56 etc. is not limited to the above-described configuration, and it may be a configuration including an SSD instead of an HDD, or a configuration using an external storage medium such as a USB memory. Also, the storage device 55 may be a storage medium such as a DVD-RAM, or a combination thereof. Further, the storage device 55 for storing the NC program 56 etc. may be a server or a network storage etc.

[0020] Further, the machine tool 10 includes a control device 17 and a plurality of drive circuits 20 that connect each of the above-described devices (work spindle device 12, turret device 13, loader 14, tool sensor 15, operation panel 16). The numerical control device 51 can control each device via the drive circuit 20 by executing the NC program 56 and the control program 57 stored in the storage device 55 with the CPU 54. The drive circuit 20 is, for example, a driver circuit (motor driver) or an amplifier circuit for amplifying signals. The PLC 52 is a Programmable Logic Controller. The PLC 52 executes, for example, a ladder program 59 stored in the PLC 52 and performs sequence processing on various signals by a ladder circuit. The PLC 52 is connected to the numerical control device 51 via a communication bus 60 and performs input / output of signals with the numerical control device 51.

[0021] Also, the control program 57 is, for example, a program that executes parameter setting processing shown in FIG. 3 described later. Further, the corresponding data 58 stores data used when determining parameters for controlling the spindle motor 22 in the parameter setting processing (see FIG. 5). Details of the control program 57 and the corresponding data 58 will be described later.

[0022] Furthermore, in the following explanation, the fact that the numerical control device 51 of the control device 17 executes programs such as the NC program 56 and the control program 57 to control each device may be simply described by the device name or program name. For example, the statement "The control device 17 controls the loader 14 to hand over the workpiece W" means "The control device 17 executes the NC program 56 on the CPU 54, and controls the loader 14 based on the NC program 56 to hand over the workpiece W."

[0023] The control device 17 controls each device in the configuration described above to perform machining on the workpiece W. For example, when the control device 17 receives an instruction to start machining based on an operation input to the control panel 16, it executes the specified NC program 56 and controls each device. For example, the control device 17 controls the loader 14 to transfer the workpiece W received by the loader 14 from the device of the previous process to the chuck mechanism 31 of the workpiece spindle device 12. At this time, the control device 17 performs spindle orientation to rotate the spindle 23 (chuck mechanism 31) to a receiving position where the workpiece W before machining is received from the loader 14 to the chuck mechanism 31, and where the chuck jaws 32 and the chuck 37 of the loader 14 do not interfere with each other. The control device 17 controls the spindle motor 22 using the parameters set in the parameter setting process described later, and performs spindle orientation to rotate the spindle 23 to the transfer position and stop it. Once the workpiece W has been received, the control device 17 controls the spindle motor 22 to rotate the workpiece W, which is held in the chuck mechanism 31, around the workpiece spindle 28. The control device 17, for example, specifies a command speed for rotating the spindle motor 22 to rotate the workpiece W at the desired rotational speed. The control device 17 also controls the turret device 13 to rotate the tool post 36, index the desired cutting tool 35, and processes the workpiece W with the indexed cutting tool 35. Once the processing is complete, the control device 17 transfers the workpiece W from the workpiece spindle device 12 to the loader 14 and transports the processed workpiece W to the next processing device. At this time, the control device 17 performs spindle orientation, rotating the spindle 23 to a rotational position where the chuck jaws 32 and the chuck 37 of the loader 14 do not interfere with each other, which is the transfer position for transferring the processed workpiece W from the chuck mechanism 31 to the loader 14. The control device 17 controls the spindle motor 22 using the parameters set in the parameter setting process and performs spindle orientation, which involves rotating the spindle 23 to the handover position and stopping it. The control device 17 also performs wear measurement as described above at a predetermined timing. To avoid interference between the tool sensor 15 and the chuck mechanism 31 during measurement, the control device 17 performs spindle orientation, which involves rotating the spindle 23 to the retracted position (the position indicated by the solid line in Figure 2) and stopping it.The predetermined timing referred to here is, for example, the timing when the machining of the workpiece W is completed. As described above, the control device 17 controls the spindle motor 22 using the parameters set in the parameter setting process, even when orienting the spindle to this retracted position.

[0024] Here, the spindle motor 22 is a so-called spindle motor, for example, a rated output motor. As shown in Figures 1 and 2, the spindle motor 22 is fitted with an encoder 29 that outputs position information corresponding to the rotational position of the spindle motor 22. The control device 17 controls the spindle motor 22 using the position information of the encoder 29 when performing each of the spindle orientations (hereinafter sometimes referred to as each spindle orientation) for the retracted position, receiving position, and handover position described above. Therefore, the parameters set in the parameter setting process are the parameters used when rotating to these three rotational positions, and are the parameters used when controlling the spindle motor 22 using the position information of the encoder 29.

[0025] On the other hand, the control device 17 controls the rotation of the spindle motor 22 in order to rotate the spindle 23 at several hundred or several thousand rpms during machining of the workpiece W. In controlling the rotation of the spindle motor 22 during machining, the control device 17 controls the spindle motor 22 without using the position information of the encoder 29. For example, the control device 17 adjusts the frequency, magnitude, etc., of the current and voltage output to the spindle motor 22 from the drive circuit 20 (motor driver, motor amplifier) ​​connected to the spindle motor 22, and controls the output of the spindle motor 22 (rotational speed * drive torque) to be constant. The control device 17 also controls the rotational speed to be the specified command speed. For example, the control device 17 performs open-loop control, voltage control, current control, etc., without feeding back the position information of the encoder 29. In this way, by configuring the system to use the encoder 29 only during spindle orientation, it is possible to use a less expensive encoder as the encoder 29 compared to an encoder that outputs high-precision position information, such as those used for controlling servo motors. For example, the control device 17 does not limit the torque applied to the spindle motor 22 during machining. Therefore, the relationship between rotational speed and drive torque is such that the drive torque is 100% from the start of rotation until the command speed is reached, and when the rotational speed approaches or reaches the command speed, the drive torque is reduced according to the relationship between rotational speed and output. In addition, the control device 17 may control the rotation of the spindle motor 22 by feeding back the position information of the encoder 29 during machining of the workpiece W, similar to the control of a servo motor. Therefore, the spindle motor 22 may be a motor with a different control configuration, such as a servo motor or a stepping motor. Furthermore, the control device 17 may control the rotation of the spindle motor 22 while limiting the drive torque of the spindle motor 22 during machining.

[0026] (Regarding parameter setting process) As described above, the control device 17 controls the rotation of the spindle motor 22 in each spindle orientation. If the parameters used by the control device 17 to control the spindle motor 22 are not appropriate, a problem may occur in which the chuck mechanism 31 does not stop at the desired rotational position (such as the receiving position) during spindle orientation. Specifically, for example, when changing the type of workpiece W, the operator changes the type of chuck mechanism 31 and chuck jaws 32. The operator places the tool sensor 15 at the inspection position and confirms the rotational position of the chuck mechanism 31, i.e., the retracted position, where the chuck jaws 32 and the tool sensor 15 do not interfere. The operator also places the loader 14 at the position where the workpiece W will be transferred to the chuck mechanism 31 before machining, and confirms the rotational position of the chuck mechanism 31, i.e., the receiving position, where the chuck jaws 32 and the chuck 37 of the loader 14 do not interfere. Furthermore, the operator positions the loader 14 at a location where it will receive the processed workpiece W from the chuck mechanism 31, and confirms the rotational position of the chuck mechanism 31, i.e., the transfer position, where the chuck jaws 32 and the chuck 37 of the loader 14 do not interfere with each other. The operator inputs the three rotational positions confirmed in the above work by operating the control panel 16. In each of the above spindle orientations, the control device 17 sets the set rotational position (rotation angle, etc.) to the target rotational position and stops the spindle 23. The control device 17 may also accept the setting of a common rotational position value for at least two of the above three rotational positions.

[0027] On the other hand, the weight of the chuck mechanism 31, chuck jaws 32, and workpiece W varies depending on the type of each component. In particular, the total weight of the chuck mechanism 31 and chuck jaws 32 can range from several tens of kilograms for lighter components to approximately 100 kilograms for heavier ones. Therefore, the moment of inertia applied to the spindle 23 during rotation fluctuates according to the weight of each component, such as the chuck mechanism 31. If the parameters in spindle orientation are not appropriate, vibration may occur in the rotation of the spindle 23, or the spindle 23 may rotate beyond the target rotation position. As a result, it becomes impossible to stop the spindle 23 at the rotation position set by the operator. Therefore, the control device 17 of this embodiment estimates the inertia value of the spindle 23 from the magnitude of the drive torque of the spindle motor 22 and the time it takes for the spindle motor 22 to reach the commanded speed by performing a test operation, and sets the parameters for controlling the spindle motor 22 in spindle orientation based on the estimated inertia value.

[0028] In this disclosure, the values ​​related to inertia include, for example, the weight of the chuck mechanism 31, the weight of the chuck jaws 32, the weight of the workpiece W, the total weight of these three components, and the moment of inertia acting on the spindle 23. Parameters that can be set by test operation include, for example, the gain of the spindle motor 22 (position gain, speed loop gain, etc.), the current value supplied to the spindle motor 22, and the applied voltage value. Alternatively, the acceleration and maximum speed used to control the rotation of the spindle motor 22 may be used as parameters. Furthermore, parameters that can be used include the direction in which the spindle motor 22 (spindle 23) is rotated during spindle orientation, and the setting value for whether or not to perform a shortcut.

[0029] Figure 3 shows a flowchart of the parameter setting process. The control device 17 starts the process shown in Figure 3 when it receives an instruction from the operator to perform the parameter setting process via the control panel 16. Note that the conditions for starting the process shown in Figure 3 are not limited to the conditions for receiving an instruction to start the parameter setting process. For example, the control device 17 may perform the process shown in Figure 3 to set the parameters before starting machining when it receives an instruction to start machining the workpiece W. The following explanation will describe the case where position gain is used as the parameter to be set. Also, to avoid making the explanation complicated, it will be explained assuming that the same parameter is used in each of the spindle orientations described above. Furthermore, the case where the total weight M of the chuck mechanism 31, chuck jaws 32, and workpiece W is used as the value related to the estimated inertia will be described.

[0030] Figure 4 shows the adjustment screen 71 that receives instructions to execute the parameter setting process. When the control device 17 receives a predetermined operation input to the touch panel 41, the CPU 54 executes the control program 57 and displays the adjustment screen 71 shown in Figure 4 on the touch panel 41. The control device 17 displays an execute button 72, an adjustment result display unit 73, and a close button 74 on the adjustment screen 71. For example, the operator operates the execute button 72 with the workpiece W before processing held in the chuck mechanism 31. Note that the operation of setting the workpiece W in the chuck mechanism 31 may be automatically performed by the control device 17 controlling the loader 14.

[0031] When the control device 17 receives an operation input for the execution button 72, it executes step 1 (hereinafter simply referred to as S) in Figure 3 and performs a test operation. The control device 17 executes the NC program 56 for the test operation and rotates the spindle motor 22. The control device 17 sets a target command speed and controls the spindle motor 22 so that the spindle 23 rotates at the command speed. The command speed is, for example, 500 rpm or 1000 rpm. In addition, the control device 17 does not limit the torque of the spindle motor 22 when controlling the rotation of the spindle motor 22 during the test operation. Therefore, the drive torque of the spindle motor 22 increases to 100% until it reaches a value close to the command speed, or until it reaches the command speed, for example, during machining. For this reason, only one value (100%) may be set as the value of the drive torque T in the corresponding data 58 in Figure 5, which will be described later. However, if torque limiting is to be performed during test operation, or if the drive torque T fluctuates, different magnitudes of drive torque T may be set in the corresponding data 58, as shown in Figure 5. The control device 17 executes control specifying the command speed to the spindle motor 22 via the drive circuit 20, and after the spindle motor 22 starts rotating, it rotates the spindle motor 22 for a predetermined time. This predetermined time is the time required for the rotation speed of the spindle 23 (spindle motor 22) to reach the command speed (target rotation speed). After the predetermined time has elapsed, the control device 17 stops the rotation of the spindle motor 22. In addition, the control device 17 may execute control to limit the drive torque (maximum torque) of the spindle motor 22 during test operation.

[0032] Next, the control device 17 detects the drive torque T of the spindle motor 22 and the time TM for the spindle motor 22 to reach the commanded speed during the test operation of S1 (S2). The control device 17 sets the position gain G based on the total weight M estimated from the detected drive torque T and the time TM (S2). The method for detecting the drive torque T is not particularly limited. For example, a method can be employed to estimate the drive torque T from the current value of the current flowing through the drive circuit 20 (motor driver) that drives the spindle motor 22. The control device 17 may also monitor the current value of the current supplied from the drive circuit 20 to the spindle motor 22 and detect the drive torque T based on the current value. The drive torque T may be the maximum torque of the spindle motor 22 or the average torque during the test operation. Alternatively, the machine tool 10 may be equipped with a torque sensor that detects the drive torque T of the spindle motor 22 using a strain gauge or the like. The control device 17 may then detect the drive torque T based on the value detected by the torque sensor.

[0033] Furthermore, the control device 17 detects the rotational speed of the spindle 23 based on the position information of the encoder 29, for example. The control device 17 measures the time from the moment a command speed is issued to the drive circuit 20 until the rotational speed of the spindle 23 reaches the command speed, as the arrival time TM. However, the method of measuring the arrival time TM is not limited to the method described above. The machine tool 10 may also be equipped with a sensor to detect the rotational speed of the spindle 23. The control device 17 may also measure the time from the moment the spindle motor 22 starts rotating until the rotational speed of the spindle 23 reaches the command speed, as the arrival time TM.

[0034] Figure 5 shows an example of data set in the corresponding data 58. As shown in Figure 5, the corresponding data 58 has multiple sets of combinations registered that relate the drive torque T, arrival time TM, total weight M of the chuck mechanism 31, etc., and the position gain G to be set. The column for drive torque T has different drive torque values ​​(T1, T2, etc.) set. As mentioned above, if the drive torque T becomes 100% during the test operation, only the combinations in which the drive torque T becomes 100% may be set in the corresponding data 58. In this case, the column for drive torque T will have only one value (100%).

[0035] Similarly, different arrival times (TM1, TM2, etc.) are set for arrival time TM. Total weight M is set to include the weight (M1, M2, etc.) of the attached chuck mechanism 31, chuck jaws 32, and workpiece W (workpiece W before machining after setup change). The values ​​and combinations in the columns for drive torque T and arrival time TM are the values ​​and combinations of drive torque T and arrival time TM when the spindle 23 is rotated at the commanded speed of the test operation described above, with the chuck mechanism 31, chuck jaws 32, and workpiece W, which have a total weight corresponding to the values ​​in the column for total weight M, attached to the spindle 23.

[0036] The driving torque T and the time to reach the target speed TM vary depending on the total weight M. For example, if the driving torque T is constant, the heavier the total weight M, the longer the time it takes to reach the target speed from the start of rotation, i.e., the time to reach the target speed TM. Also, if the total weight M is constant, increasing the driving torque T makes it possible to shorten the time to reach the target speed TM.

[0037] The data for the combinations of drive torque T and arrival time TM described above can be set to values ​​obtained from pre-measurements using the machine tool 10, for example. In the pre-measurements, for example, a weight equivalent to the total weight M is attached to the spindle 23, the spindle motor 22 is rotated at the commanded speed of the test operation, and the arrival time TM is measured under different conditions by changing the weight of the weight and the drive torque T. Based on the results of the pre-measurements, the pre-measured drive torque described above is set in the drive torque T column, the measured arrival time is set in the arrival time TM column, and the weight of the attached weight is set in the total weight M. In addition, in the pre-measurements, it is also possible to measure by actually attaching the chuck mechanism 31, chuck jaws 32, and workpiece W to the spindle 23 without using a weight. Therefore, the drive torque T and arrival time TM can be measured with the chuck mechanism 31 etc., which will be the weight for each condition, attached.

[0038] The control device 17 detects data from the corresponding data 58 shown in Figure 5 that matches the combination of drive torque T and arrival time TM detected in the test operation S1. The control device 17 determines the total weight M of the row with the detected combination as the estimated total weight M (S2). The control device 17 also determines the position gain G of the row with the detected combination as a parameter to be set (S2). This allows setting an appropriate position gain G according to the total weight M based on the total weight M estimated from the drive torque T and arrival time TM.

[0039] The control device 17 displays the position gain G determined in S2 on the adjustment screen 71 (S3). As shown in Figure 4, the display unit 73 displays the position gain G before adjustment (position gain before adjustment in Figure 4), the position gain G after adjustment (position gain after adjustment in Figure 4), and the date and time the parameter setting process was performed (date and time of execution in Figure 4), one line at a time. The control device 17 executes the parameter setting process each time the execution button 72 is operated, displays the position gain G etc. of the execution result on the top line, and displays past execution results sequentially down. The control device 17 displays the value that was set as the position gain G before the parameter setting process in the position gain G before adjustment column, and displays the position gain G determined by the test operation in the position gain G after adjustment column. The control device 17 also displays, for example, the time when the instruction to start the parameter setting process was received in the date and time of execution column. The control device 17 also displays past execution results in response to operations on the scroll button 75 displayed on the display unit 73. In this way, the operator can set the position gain G corresponding to the weight (inertia) of the chuck mechanism 31 attached to the spindle 23 simply by pressing the execute button 72. When the control device 17 receives an input for operation on the close button 74, it closes the display of the adjustment screen 71.

[0040] After the operator executes the parameter setting process, the operator causes the machine tool 10 to perform the machining operation on the workpiece W. The control device 17 controls the spindle motor 22 with the position gain G set in the parameter setting process when rotating the spindle 23 in each spindle orientation. The control device 17 controls the rotation, deceleration, stopping, etc. of the spindle motor 22 with the set position gain G. This allows the chuck mechanism 31 to be rotated and stopped at an appropriate rotation position that avoids interference with other parts. For example, if the total weight M is heavy, the position gain G or other gains can be lowered to simulate stronger braking, allowing the spindle motor 22 to be stopped at the target rotation position.

[0041] Therefore, as described above, in this embodiment, the parameters for controlling the spindle motor 22 during spindle orientation are the parameters for controlling the spindle motor 22 when rotating the spindle 23 to the rotation position in each spindle orientation and stopping it. Specifically, the rotation position is the receiving position where the workpiece W before machining is received from the loader 14 to the chuck mechanism 31. The rotation position is also the handover position where the workpiece W after machining is transferred from the chuck mechanism 31 to the loader 14. Furthermore, the rotation position is a retracted position that avoids interference between the tool sensor 15, which measures the amount of wear of the cutting tool 35 attached to the turret device 13, and the chuck mechanism 31. As a result, the chuck mechanism 31 can be stopped accurately at each of the receiving position, handover position, and retracted position, and contact between the chuck jaws 32 and the chuck 37 can be avoided during receiving, etc.

[0042] Furthermore, during the test operation, the control device 17 estimates the total weight M from the time TM required to reach a predetermined command speed while the spindle motor 22 is rotated at a predetermined command speed, without limiting the drive torque T of the spindle motor 22. For example, a rated output motor may be used as the spindle motor, and a high-precision encoder like that of a servo motor may not be installed. In such cases, the spindle motor may not have a torque limiting configuration, or torque limiting may not be performed. Therefore, the method of estimating the total weight M from the time TM required to reach the command speed without setting a torque limit is extremely effective when estimating values ​​related to the inertia of the spindle 23. By commanding only the rotational speed and executing the test operation without limiting the drive torque T, the total weight M can be estimated and the parameters can be set.

[0043] Furthermore, the control device 17 detects the position gain G corresponding to the total weight M estimated by the test operation from the correspondence data 58, which associates the total weight M of the chuck mechanism 31 with the position gain G, and sets the detected position gain G as a parameter to be used for control. This allows the parameter to be determined without using calculation formulas or the like. By setting the total weight M and the position gain G corresponding to that total weight M in the correspondence data 58 in advance, an appropriate position gain G can be set from the estimated total weight M.

[0044] Furthermore, during spindle orientation, the control device 17 controls the spindle motor 22 with a set position gain G and also controls the spindle motor 22 based on position information output from the encoder 29. On the other hand, when controlling the rotation of the spindle motor 22 when machining the workpiece W, the control device 17 controls the spindle motor 22 without using the position information output from the encoder 29. This allows the rotational position of the chuck mechanism 31 to be adjusted to the retracted position, etc., based on the position information of the encoder 29 during spindle orientation. Also, when machining the workpiece W, the spindle motor 22 can be rotated by specifying only the rotational speed, without using the position information of the encoder 29. In other words, when machining the workpiece W at a predetermined rotational speed, the position information of the encoder 29 is unnecessary. An encoder with the accuracy required for spindle orientation can be used as the encoder 29, and it can be an inexpensive encoder compared to a high-precision encoder that can be attached to a servo motor.

[0045] Incidentally, the correspondence between the terms used in this embodiment and the terms used in the claims will be explained below. The loader 14 in this embodiment is an example of the robot of this disclosure. Total weight M is an example of a value related to the spindle inertia and the weight of the chuck mechanism. Position gain G is an example of a parameter.

[0046] As described above, this embodiment provides the following effects. In one aspect of this embodiment, the control device 17 performs a test operation to rotate the spindle 23 by controlling the spindle motor 22 (S1), and sets a position gain for controlling the spindle motor 22 in spindle orientation based on the magnitude of the drive torque T of the spindle motor 22 in the test operation and the total weight M estimated from the time TM for the spindle motor 22 to reach the commanded speed (S2).

[0047] According to this, when the chuck mechanism 31 or chuck jaws 32 are changed in accordance with the setup of the workpiece W, the total weight M of the modified chuck mechanism 31, etc. can be estimated by performing a test operation. Based on the estimated total weight M, the position gain of the spindle orientation can be set to set parameters corresponding to the total weight M of the chuck mechanism 31, etc.

[0048] It goes without saying that this disclosure is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of this disclosure. For example, the processing details of the parameter setting process in the above embodiment are just an example and can be changed as appropriate. For instance, the parameters to be set are not limited to the position gain G, but may also include the speed loop gain, maximum speed, acceleration, and maximum torque used to control the spindle motor 22. Furthermore, the control device 17 may execute the parameter setting process and set multiple parameters simultaneously or sequentially. Accordingly, the corresponding data 58 may contain data that combines multiple types of parameters. Furthermore, the control device 17 may set parameters from at least one of the values ​​of the magnitude of the drive torque T and the arrival time TM during the test operation of S1. For example, if the spindle motor 22 is configured to operate with a drive torque T of 100% without torque limitations, the total weight M may be estimated from the arrival time TM and the total weight M may be set. In this case, it is not necessary to set the drive torque T in the corresponding data 58. Furthermore, if the main shaft motor 22 is configured to have its torque limited and the drive torque T fluctuates, the total weight M may be estimated from the drive torque T and the total weight M may be set. In this case, it is not necessary to set the arrival time TM in the corresponding data 58. Furthermore, the control device 17 may change the command speed during test operation and estimate the inertia value from the command speed. In this case, the command speed value may be set in the corresponding data 58. Furthermore, in S2, if no combination that perfectly matches the detected drive torque T or arrival time TM exists in the corresponding data column 58, the control device 17 may set the position gain G as a parameter to use, which is associated with a combination of values ​​that are closer to the detected drive torque T or arrival time TM.

[0049] Furthermore, although the above embodiment describes a case where the same parameters are set as parameters for each spindle orientation, it is not limited to this. The control device 17 may set different parameters for each spindle orientation of the retracted position, receiving position, and handover position. In this case, when setting the parameters for the receiving position, the operator may execute the process in Figure 3 with the workpiece W removed, and when setting the parameters for the handover position, the operator may execute the process in Figure 3 with the machined workpiece W attached. Furthermore, it is not necessary to set the total weight M in the corresponding data 58. In this case, the control device 17 may determine the position gain G from the drive torque T and the arrival time TM. The control device 17 may also display the total weight M estimated from the corresponding data 58 on the adjustment screen 71. Furthermore, during the test operation of S1, the control device 17 may perform an operation in which the spindle motor 22 is rotated only by the operating angle during spindle orientation, rather than rotating it to its full extent. Furthermore, the control device 17 may set parameters to control the spindle motor 22 when rotating the spindle 23 to at least one of the following rotational positions: the receiving position, the handover position, and the retracted position, and then stopping it. Therefore, the control device 17 may only set parameters for rotating to the handover position. The weight of the chuck mechanism in this disclosure is not limited to the total weight M including the chuck mechanism 31, chuck jaws 32, and workpiece W, but may also be the weight of the chuck mechanism 31 alone, or the weight of the chuck mechanism 31 and chuck jaws 32. Furthermore, the configuration of the machine tool 10 shown in Figure 1 is just one example. For example, the machine tool 10 may be equipped with a reversing device for inverting the workpiece, a measuring device for inspecting the workpiece after processing, etc. Also, the machine tool 10 may be configured without a loader 14.

[0050] Furthermore, the contents of this disclosure are not limited to the dependency relationships described in the claims. For example, this specification also discloses a technical concept in which "the machine tool described in claim 1 or claim 2" in claim 4 is changed to "the machine tool described in any one of claims 1 to 3". Also, this specification discloses a technical concept in which "the machine tool described in claim 1 or claim 2" in claim 5 is changed to "the machine tool described in any one of claims 1 to 4". [Explanation of Symbols]

[0051] 10 Machine tool, 13 Turret device, 14 Loader (robot), 15 Tool sensor, 17 Control device, 22 Spindle motor, 23 Spindle, 29 Encoder, 31 Chuck mechanism, 35 Cutting tool, 58 Corresponding data: T Drive torque, TM Time to reach, M Total weight (value related to spindle inertia, weight of chuck mechanism), G Position gain (parameter), W Workpiece.

Claims

1. A spindle to which a chuck mechanism for gripping a workpiece can be attached, A spindle motor that rotates the spindle, A control device for controlling the rotation of the spindle motor, Equipped with, The control device is A machine tool that performs a test operation to rotate the spindle by controlling the spindle motor, and sets parameters for controlling the spindle motor in spindle orientation based on a value related to the spindle inertia estimated from at least one of the magnitude of the driving torque of the spindle motor in the test operation and the time it takes for the spindle motor to reach the commanded speed.

2. The parameters used to control the spindle motor in the spindle orientation are: A parameter for controlling the spindle motor when rotating the spindle to at least one rotation position and stopping it, among a receiving position for receiving a workpiece from a robot to the chuck mechanism attached to the spindle before machining, a transfer position for transferring a workpiece from the chuck mechanism to the robot after machining, and a retracted position to avoid interference between the tool sensor, which measures the amount of wear of a cutting tool attached to a turret device, and the chuck mechanism.

3. The aforementioned main shaft motor is It is a spindle motor, The control device is The value relating to the spindle inertia is estimated from the value of the time it takes for the spindle motor to reach the commanded speed during the test operation. The machine tool according to claim 1 or 2, wherein, in the test operation, the value relating to the spindle inertia is estimated from the value of the arrival time when the spindle motor is rotated at a predetermined command speed without limiting the driving torque of the spindle motor.

4. The aforementioned value relating to inertia is, This is the weight of the chuck mechanism, The control device is The machine tool according to claim 1 or 2, wherein the weight of the chuck mechanism attached to the spindle is estimated from at least one of the magnitude of the drive torque of the spindle motor in the test operation and the time it takes for the spindle motor to reach the commanded speed, the parameter corresponding to the weight of the chuck mechanism estimated by the test operation is detected from correspondence data where the weight of the chuck mechanism and the parameter are associated, and the detected parameter is set as the parameter for controlling the spindle motor in the spindle orientation.

5. The aforementioned main shaft motor includes: An encoder is attached that outputs position information corresponding to the rotational position of the main shaft motor. The control device is In the spindle orientation operation, the spindle motor is controlled using the parameter set based on the inertia value of the spindle, and the spindle motor is also controlled based on the position information output from the encoder. The machine tool according to claim 1 or claim 2, wherein, in controlling the rotation of the spindle motor when machining the workpiece, the spindle motor is controlled without using the position information output from the encoder.

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