Machine tool

Abstract

A machine tool according to one embodiment of the present disclosure is provided with: a plurality of servomotors; a plurality of servo amplifiers which respectively drive the servo motors; the numerical controller inputs command values to the plurality of servo amplifiers in accordance with a machining program, and includes a motor classification unit, a control unit, and a control unit. A classification unit that classifies the plurality of servo motors into a continuous drive motor that requires continuous excitation during execution of the machining program and an intermittent drive motor that can at least temporarily stop excitation during execution of the machining program; and a stop control unit that stops excitation of at least one of the intermittent drive motors during execution of the machining program.

Description

Technical Field

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

[0002] In machine tools, multiple servo motors are coordinated to process workpieces. Generally speaking, servo motors are driven by current supplied from a one-to-one corresponding servo amplifier. Even when the output shaft is not displaced, the servo motor is still excited and the output is adjusted so that the rotation position matches the target position at that time.

[0003] As described above, generally, the servo motor of a machine tool is set to be always excited and consume power. Exceptionally, in order to prevent the feed axis from colliding (interfering with other axes or movable limits) when a power outage occurs, a technology has been proposed to cut off the power supply to the servo motor when an abnormality is detected (see, for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-96929 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In recent years, the demand for energy saving has increased, and machine tools are required to be more energy-efficient. Therefore, a technology that can suppress the power consumption of a servo motor is desired.

[0009] Means for solving problems

[0010] A machine tool according to one embodiment of the present invention comprises: a plurality of servo motors; a plurality of servo amplifiers, which respectively drive the servo motors; a numerical control device, which inputs instruction values ​​to the plurality of servo amplifiers according to a machining program, the numerical control device comprising: a motor classification unit, which classifies the plurality of servo motors into continuously driven motors which require continuous excitation during the execution of the machining program and intermittently driven motors which can at least temporarily stop excitation during the execution of the machining program; and a stop control unit, which stops the excitation of at least one of the intermittently driven motors during the execution of the machining program. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram showing the structure of a machine tool according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1It is a schematic diagram showing the structure of a machine tool 1 according to one embodiment of the present disclosure.

[0013] The machine tool 1 comprises: a plurality of servo motors 11, 12, 13, 14; a plurality of servo amplifiers 21, 22, 23, 24, which respectively drive the servo motors 11, 12, 13, 14; a state sensor 30, which detects the operating state of the component driven by the fourth servo motor 14; and a numerical control device 40, which inputs instruction values ​​to the plurality of servo amplifiers 21, 22, 23, 24 according to a machining program.

[0014] The servo motors 11, 12, 13, and 14 include: a spindle motor 11 that rotates the tool and the workpiece relative to each other; a plurality of positioning axis motors 12 and 13 that move the tool and the workpiece relative to each other; and an auxiliary motor 14 that drives peripheral devices (e.g., a servo motor that drives a door). Figure 1 Although the number of the servo motors 11 , 12 , 13 , 14 and the servo amplifiers 21 , 22 , 23 , 24 shown in the figure is four respectively, the actual number is not limited and is usually greater than four.

[0015] In addition, as described in detail later, in this embodiment, the spindle motor 11 and the positioning axis motors 12 and 13 are operated as continuous drive motors that require continuous excitation during the execution of the machining program, and the auxiliary motor 14 is operated as an intermittent drive motor that can at least temporarily stop excitation during the execution of the machining program.

[0016] The servo amplifiers 21, 22, 23, 24 are provided in one-to-one correspondence with the servo motors 11, 12, 13, 14, and supply excitation currents for exciting the windings of the corresponding servo motors 11, 12, 13, 14. The servo amplifiers 21, 22, 23, 24 may be configured to adjust the current input to the servo motors 11, 12, 13, 14 so that the speed of the servo motors 11, 12, 13, 14 matches the speed indicated by the command value input from the numerical controller 40.

[0017] The servo amplifiers 21, 22, 23, 24 are respectively supplied with power from the high voltage power supply 25, and with control power from the low voltage power supply 26. Primary circuit breakers 211, 221, 231, 241 are respectively provided on the electrical path for supplying power from the high voltage power supply 25 to the servo amplifiers 21, 22, 23, 24, and are operated by the numerical control device 40. In addition, relays 212, 222, 232, 242 are respectively provided on the electrical path for supplying control power from the low voltage power supply 26 to the servo amplifiers 21, 22, 23, 24, and are operated by the numerical control device 40.

[0018] In addition, the servo amplifiers 21, 22, 23, 24 are configured to block output when a stop signal is input from the numerical controller 40, and to stop the excitation of the servo motors 11, 12, 13, 14. The mechanism for stopping the excitation may be a secondary circuit breaker that can block the electrical path connecting the main body of the servo amplifiers 21, 22, 23, 24 and the servo motors 11, 12, 13, 14.

[0019] The state sensor 30 may be configured to detect the position of a component, such as a door, driven by the auxiliary motor 14. The state sensor 30 may be, for example, a photoelectric cell, a limit switch, or the like.

[0020] The numerical control device 40 includes: a pre-reading control unit 41, a command value generating unit 42, a motor classification unit 43, a stop control unit 44, and an intermittent drive monitoring unit 45. The numerical control device 40 can be implemented by one or more computer devices that have a memory, a processor (CPU), an input / output interface, etc., and execute an appropriate control program. The above-mentioned components of the numerical control device 40 are components that classify the functions of the numerical control device 40, and may not be clearly distinguished in terms of physical structure and program structure.

[0021] The pre-reading control unit 41 pre-reads the machining program before actually operating the servomotors 11, 12, 13, 14, and corrects the motion described in the machining program. More specifically, in order to perform machining according to the machining program as accurately as possible, the pre-reading control unit 41 considers the mechanical limitations of the servomotors 11, 12, 13, 14, such as the maximum speed, the maximum acceleration, the maximum jerk, etc., and calculates the speed and the like at each moment to be instructed to the servomotors 11, 12, 13, 14 in advance, and stores the information related to the calculated motion until the servomotors 11, 12, 13, 14 are actually operated.

[0022] The command value generating unit 42 generates a command value input to the servo amplifiers 21, 22, 23, and 24 based on the information related to the operation corrected by the look-ahead control unit 41. The command value generating unit 42 may be configured to correct the command value input to the servo amplifiers 21, 22, 23, and 24 in consideration of a feedback signal indicating the actual speed of the servo motors 11, 12, 13, and 14.

[0023] The motor classification unit 43 classifies the plurality of servo motors 11 , 12 , 13 , 14 into continuous drive motors 11 , 12 , 13 that need to be continuously excited during execution of a machining program and intermittent drive motors 14 that can at least temporarily stop excitation during execution of a machining program.

[0024] The motor classification unit 43 may also classify the continuous drive motor and the intermittent drive motor according to the setting when the machine tool 1 is installed, but it is preferably configured to be able to classify the continuous drive motor and the intermittent drive motor according to the input from the outside. The input for classifying the continuous drive motor and the intermittent drive motor may be performed by the user's operation or by the communication between the numerical control device 40 and an external server or the like.

[0025] In addition, the motor classification unit 43 may also be configured to classify the continuous drive motor and the intermittent drive motor according to each processing program. For example, in a machine tool equipped with a tool changer, when the servo motor of the tool changer executes a processing program in which the tool is frequently changed, it is preferably treated as a continuous drive motor in order to prevent processing delays, and when the servo motor of the tool changer executes a processing program in which the tool is not changed, it is preferably treated as an intermittent drive motor in order to suppress energy consumption. Therefore, the motor classification unit 43 may also store information that determines the classification of the continuous drive motor and the intermittent drive motor in association with the processing program.

[0026] The motor classification unit 43 may also be configured to confirm information related to the classification of the continuous drive motor and the intermittent drive motor additionally described in the processing program. However, preferably, the motor classification unit 43 is configured to classify the continuous drive motor and the intermittent drive motor by analyzing the processing content described in the processing program, so that the existing processing program that does not record such information can be used. Specifically, the motor classification unit 43 may be configured to classify the servo motors that are judged as not needing to be driven for more than a predetermined stop period in the processing program as intermittent drive motors. In addition, the "stop period" may be determined not only as a time unit, but also as a unit, for example, the number of program blocks in the processing program. As a specific stop period, it can be set to, for example, within a range of more than 3 minutes and less than 10 minutes, more than 1000 program blocks and less than 5000 program blocks, and the like.

[0027] The motor classification unit 43 may also be configured to confirm the content of the machining program in advance before the execution of the machining program to determine the intermittent drive motor. In addition, in order to reduce the waiting time for machining, the motor classification unit 43 may also be configured to classify the servo motors that are judged to be unnecessary to drive for more than the stop period from now on based on the content of the machining program pre-read by the pre-reading control unit 41 as intermittent drive motors. In this case, the classification of the continuous drive motor and the intermittent drive motor can be dynamically changed during the execution of the machining program.

[0028] The stop control unit 44 stops the excitation of at least one of the intermittent drive motors during the execution of the machining program. That is, the stop control unit 44 stops the output of the excitation current of the servo amplifier 24 driving the intermittent drive motor 14 that is not useful for machining. In this way, it is possible to prevent machining delays while suppressing power consumption.

[0029] The stop control unit 44 not only stops the output of the excitation current of the servo amplifier 24 driving the intermittent drive motor 14, but also blocks the supply of power to the servo amplifier 24, that is, disconnects the primary circuit breaker 241. In this way, power consumption can be further suppressed. The stop control unit 44 can also further block the supply of control power to the servo amplifier 24 driving the intermittent drive motor 14, that is, disconnects the relay 242. In this way, the power consumption of the servo amplifier 24 in the control circuit can also be suppressed. In addition, in order to prevent malfunction, it is preferred that the output of the excitation current is stopped, the supply of power is blocked, and the supply of control power is blocked in this order. In addition, it is preferred that when starting the excitation of the intermittent drive motor 14, power is turned on in the opposite order.

[0030] When the intermittent drive motors are dynamically classified based on the contents of the machining program pre-read by the motor classification unit 43, it is preferred that the stop control unit 44 immediately stops the excitation of the identified intermittent drive motor when the motor classification unit 43 identifies the intermittent drive motor, thereby suppressing power consumption.

[0031] The stop control unit 44 may also preliminarily block the power supply to other devices associated with the intermittent drive motor 14 in synchronization with the excitation stop of the intermittent drive motor 14. As an example, when the excitation of the auxiliary motor driving the door is stopped, the power supply to the switch for opening and closing the door and the lighting linked to the door may be blocked.

[0032] Preferably, the stop control unit 44 is configured to excite the intermittent drive motor 14 when it is determined that the intermittent drive motor 14 needs to be driven within a predetermined start-up period from now on based on the content of the machining program pre-read by the pre-read control unit 41. The "start-up period" is set to a time sufficient for starting the intermittent drive motor 14, or the number of program blocks that can ensure such time. In this way, the delay caused by starting the intermittent drive motor 14 after the action that requires the intermittent drive motor 14 in actual machining can be avoided.

[0033] The intermittent drive monitoring unit 45 checks whether the intermittent drive motor 14 performs unexpected actions during the period when the stop control unit stops the excitation of the intermittent drive motor (auxiliary motor) 14. The intermittent drive monitoring unit 45 can be configured to monitor the detection value of the state sensor 30, or it can be confirmed by monitoring the feedback from the encoder when the encoder inside the intermittent drive motor 14 that stops the excitation is valid. In this way, the machine tool 1 can still ensure the safety of the actions related to the intermittent drive motor 14 during the period when the control of the intermittent drive motor 14 is stopped.

[0034] As described above, since the machine tool 1 includes a motor classification unit 43 that classifies multiple servo motors 11, 12, 13, and 14 into continuous drive motors 11, 12, 13 and intermittent drive motors 14, and a stop control unit 44 that stops the excitation of the intermittent drive motor 14 during the execution of the machining program, the power consumption caused by the excitation of the intermittent drive motor 14 can be suppressed.

[0035] The following supplementary notes are further disclosed regarding the above-mentioned embodiment and modified examples.

[0036] (Note 1)

[0037] A machine tool (1) comprises: a plurality of servo motors (11, 12, 13, 14); a plurality of servo amplifiers (21, 22, 23, 24) which respectively drive the servo motors (11, 12, 13, 14); a numerical control device (40) which inputs instruction values ​​to the plurality of servo amplifiers (21, 22, 23, 24) according to a machining program, the numerical control device (40) comprising: a motor classification unit (43) which classifies the plurality of servo motors (11, 12, 13, 14) into continuously driven motors (11, 12, 13) which require continuous excitation during the execution of the machining program and intermittently driven motors (14) which can at least temporarily stop excitation during the execution of the machining program; and a stop control unit (44) which stops the excitation of at least one of the intermittently driven motors (14) during the execution of the machining program.

[0038] (Note 2)

[0039] In the machine tool (1) of Supplementary Note 1, the stop control unit (44) may block the supply of power for driving at least one servo amplifier (24) of the intermittent drive motor (14).

[0040] (Note 3)

[0041] In the machine tool (1) of Supplementary Note 2, the stop control unit (44) may also block the supply of control power to at least one servo amplifier (24) that drives the intermittent drive motor (14).

[0042] (Note 4)

[0043] In the machine tool (1) of Supplementary Notes 1 to 3, it may also be provided with: a state sensor (30) that detects the operating state of a component driven by the intermittent drive motor (14).

[0044] (Note 5)

[0045] In the machine tool (1) of Supplementary Notes 1 to 4, the motor classification unit (43) may classify the intermittent drive motors (14) according to input from the outside.

[0046] (Note 6)

[0047] In the machine tool (1) of Supplementary Notes 1 to 5, the motor classification unit (43) may classify the servo motors (11, 12, 13, 14) judged in the machining program as not needing to be driven for more than a predetermined stop period as intermittent drive motors (14).

[0048] (Note 7)

[0049] In the machine tool (1) of Appendix 6, the numerical control device (40) may also include: a pre-reading control unit (41) which pre-reads the machining program and corrects the actions described in the machining program; a motor classification unit (43) which classifies servo motors (11, 12, 13, 14) that are judged to be unnecessary to be driven for a stop period of more than a period from now on based on the contents of the machining program pre-read by the pre-reading control unit (41) as intermittent drive motors (14); and a stop control unit (44) which immediately stops the excitation of the intermittent drive motor (14) determined by the motor classification unit (43) as an intermittent drive motor (14).

[0050] (Note 8)

[0051] In the machine tool (1) of Note 7, the stop control unit (44) may also excite the intermittent drive motor (14) when it is determined that the intermittent drive motor (14) needs to be driven within a predetermined start-up period from now on based on the content of the machining program pre-read by the pre-read control unit (41).

[0052] (Note 9)

[0053] In the machine tool (1) of Supplementary Notes 1 to 8, the stop control unit (44) may block the power supply to other devices in synchronization with the excitation stop of the intermittent drive motor (14).

[0054] Although the present disclosure is described in detail above, the present disclosure is not limited to the above-mentioned embodiments. These embodiments may be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the present disclosure or the scope of the present disclosure derived from the contents recorded in the claims and their equivalents.

[0055] As an example, the machine tool of the present disclosure may include other configurations for realizing energy saving, such as activating a screen saver or turning off the power of a pump, independently of the stop control unit.

[0056] Description of Reference Numerals

[0057] 1Machine Tools

[0058] 11, 12, 13, 14 spindle motor

[0059] 21, 22, 23, 24 Servo amplifier

[0060] 211, 221, 231, 241 primary circuit breakers

[0061] 212, 222, 232, 242 relays

[0062] 25 High voltage power supply

[0063] 26 Low voltage power supply

[0064] 30 Status Sensor

[0065] 40 Numerical control device

[0066] 41 Pre-reading control unit

[0067] 42 Command value generation unit

[0068] 43 Motor Classification Department

[0069] 44 Stop control unit

[0070] 45 Intermittent drive monitoring unit.

Claims

1. A machine tool, characterized in that: have: a plurality of servo motors; a plurality of servo amplifiers, which respectively drive the servo motors; a numerical control device, which inputs command values ​​to the plurality of servo amplifiers according to a machining program, The numerical control device comprises: a motor classification unit that classifies the plurality of servo motors into continuous drive motors that need to be continuously excited during execution of the machining program and intermittent drive motors that can at least temporarily stop excitation during execution of the machining program; A stop control unit stops excitation of at least one of the intermittent drive motors during execution of the machining program.

2. The machine tool according to claim 1, characterized in that: The stop control unit blocks supply of motive power to the servo amplifier that drives at least one of the intermittent drive motors.

3. The machine tool according to claim 2, characterized in that: The stop control unit further blocks supply of control power to the servo amplifier that drives at least one of the intermittent drive motors.

4. The machine tool according to any one of claims 1 to 3, characterized in that The machine tool further includes a state sensor that detects an operating state of a component driven by the intermittent drive motor.

5. The machine tool according to any one of claims 1 to 4, characterized in that The motor classification unit classifies the intermittent drive motors according to an input from the outside.

6. The machine tool according to any one of claims 1 to 5, characterized in that The motor classification unit classifies the servo motor, which is determined not to be driven for a predetermined stop period or longer in the machining program, into the intermittent drive motor.

7. The machine tool according to claim 6, characterized in that The numerical control device further comprises: a pre-reading control unit which pre-reads the machining program and corrects the operation described in the machining program. The motor classification unit classifies the servo motor, which is determined not to be driven for more than the stop period from now on based on the content of the machining program pre-read by the pre-reading control unit, as the intermittent drive motor. When the motor classification unit identifies the intermittent drive motor, the stop control unit immediately stops excitation of the identified intermittent drive motor.

8. The machine tool according to claim 7, characterized in that: The stop control unit excites the intermittent drive motor when determining that the intermittent drive motor needs to be driven within a predetermined start-up period from now on based on the content of the machining program pre-read by the pre-read control unit.

9. The machine tool according to any one of claims 1 to 8, characterized in that The stop control unit blocks power supply to other devices in synchronization with the excitation stop of the intermittent drive motor.

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