Working machinery

Abstract

A machine tool according to an aspect of the present disclosure comprises: a plurality of servo motors; a plurality of servo amplifiers that drive the servo motors, respectively; and a numerical value control device that inputs a command value to the plurality of servo amplifiers in accordance with a processing program. The numerical value control device has: a motor classification unit that classifies the plurality of servo motors into continuous drive motors which require continuous excitation during execution of the processing program and intermittent drive motors in which excitation can be stopped at least temporarily during the execution of processing program; and a stop control unit that stops the excitation of at least one of the intermittent drive motors during the execution of the processing program.

Description

Technical Field

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

Background Art

[0002] In a machine tool, a plurality of servo motors cooperate to perform machining of a workpiece. Generally, a servo motor is driven by current supplied from a servo amplifier corresponding one-to-one. Even when the output shaft is not displaced, the servo motor is excited and its output is adjusted so that the rotational position coincides with the target position at that time.

[0003] As described above, usually, the servo motors of a machine tool are in a state of being constantly excited and consuming power. Exceptionally, in order to prevent the feed shaft from colliding (interfering with other shafts or movable limits) when a power failure occurs or the like, a technique has been proposed to cut off the power supply to the servo motors when an abnormality is detected (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, the demand for energy conservation has been increasing, and further energy conservation of machine tools is required. Therefore, a technique capable of suppressing the power consumption of servo motors is desired.

Means for Solving the Problems

[0006] A machine tool according to one aspect of the present disclosure comprises a plurality of servo motors, a plurality of servo amplifiers that drive each of the servo motors, and a numerical control device that inputs command values ​​to the plurality of servo amplifiers according to a machining program, wherein the numerical control device includes a motor classification unit that classifies the plurality of servo motors into continuous drive motors that require continuous excitation during the execution of the machining program and intermittent drive motors that can be temporarily stopped from being excited during the execution of the machining program, and a stop control unit that stops the excitation of at least one of the intermittent drive motors during the execution of the machining program. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the configuration of a machine tool according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of a machine tool 1 according to one embodiment of the present disclosure.

[0009] The machine tool 1 comprises a plurality of servo motors 11, 12, 13, 14, a plurality of servo amplifiers 21, 22, 23, 24 that drive the servo motors 11, 12, 13, 14 respectively, a state sensor 30 that detects the operating state of a workpiece driven by the fourth servo motor 14, and a numerical control device 40 that inputs command values ​​to the plurality of servo amplifiers 21, 22, 23, 24 according to a machining program.

[0010] The servo motors 11, 12, 13, and 14 include a spindle motor 11 that rotates the tool and workpiece relative to each other, multiple positioning axis motors 12 and 13 that move the tool and workpiece relative to each other, and an auxiliary motor 14 that drives peripheral equipment (for example, a servo motor that drives a door). In the simplified Figure 1, the number of servo motors 11, 12, 13, and 14 and servo amplifiers 21, 22, 23, and 24 shown are each four, but the actual number is not limited and is usually more than four.

[0011] Furthermore, as will be explained in detail later, in this embodiment, the spindle motor 11 and the positioning axis motors 12 and 13 are treated as continuous drive motors that require continuous excitation during the execution of the machining program, while the auxiliary motor 14 is treated as an intermittent drive motor that can be stopped at least temporarily during the execution of the machining program.

[0012] The servo amplifiers 21, 22, 23, and 24 are provided in one-to-one correspondence with the servo motors 11, 12, 13, and 14, and supply excitation current to excite the windings of the corresponding servo motors 11, 12, 13, and 14. The servo amplifiers 21, 22, 23, and 24 may be configured to adjust the current input to the servo motors 11, 12, 13, and 14 so that their speed matches the speed indicated by the command value input from the numerical control device 40.

[0013] Servo amplifiers 21, 22, 23, and 24 are supplied with power for operation from a high-voltage power supply 25 and control power from a low-voltage power supply 26, respectively. The circuits supplying power for operation from the high-voltage power supply 25 to the servo amplifiers 21, 22, 23, and 24 are equipped with primary breakers 211, 221, 231, and 241, respectively, which are operated by the numerical control device 40. In addition, the circuits supplying control power from the low-voltage power supply 26 to the servo amplifiers 21, 22, 23, and 24 are equipped with relays 212, 222, 232, and 242, respectively, which are operated by the numerical control device 40.

[0014] Furthermore, the servo amplifiers 21, 22, 23, and 24 are configured to shut off their output and stop the excitation of the servo motors 11, 12, 13, and 14 when a stop signal is input from the numerical control device 40. The mechanism for stopping the excitation may also be a secondary breaker capable of interrupting the circuit connecting the main bodies of the servo amplifiers 21, 22, 23, and 24 to the servo motors 11, 12, 13, and 14.

[0015] The state sensor 30 may be configured to detect the position of a component driven by the auxiliary motor 14, such as a door. The state sensor 30 may be, for example, a photoelectric sensor, a limit switch, or the like.

[0016] The numerical control device 40 comprises a look-ahead control unit 41, a command value generation 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 include, for example, memory, a processor (CPU), an input / output interface, etc., and execute an appropriate control program. The above-described components of the numerical control device 40 are classifications of the functions of the numerical control device 40 and do not necessarily need to be clearly distinguishable in terms of physical configuration and program configuration.

[0017] The look-ahead control unit 41 looks up the machining program before actually operating the servo motors 11, 12, 13, and 14, and corrects the operations described in the machining program. More specifically, the look-ahead control unit 41 takes into account the mechanical limitations of the servo motors 11, 12, 13, and 14, such as maximum speed, maximum acceleration, and maximum jerk, and calculates in advance the speed and other parameters to be instructed to the servo motors 11, 12, 13, and 14 at each given time, so that machining can be performed as accurately as possible according to the machining program. The unit stores the calculated operation-related information until the servo motors 11, 12, 13, and 14 are actually operated.

[0018] The command value generation unit 42 generates command values ​​to be input to the servo amplifiers 21, 22, 23, and 24 based on the operation-related information corrected by the look-ahead control unit 41. The command value generation unit 42 may be configured to correct the command values ​​to be input to the servo amplifiers 21, 22, 23, and 24, taking into account the feedback signals indicating the actual speed of the servo motors 11, 12, 13, and 14.

[0019] The motor classification unit 43 classifies the multiple servo motors 11, 12, 13, and 14 into continuous drive motors 11, 12, and 13 that require continuous excitation during the execution of the machining program, and intermittent drive motors 14 that can be temporarily stopped from being excited during the execution of the machining program.

[0020] The motor classification unit 43 may classify the continuous drive motor and the intermittent drive motor according to the settings at the time of installation of the machine tool 1, but is preferably configured to be able to classify the continuous drive motor and the intermittent drive motor according to an external input. The input for classifying the continuous drive motor and the intermittent drive motor may be performed by a user's operation, or may be performed by the numerical control device 40 communicating with an external server or the like.

[0021] Also, the motor classification unit 43 may be configured to classify the continuous drive motor and the intermittent drive motor for each machining program. For example, in a machine tool equipped with a tool changer, the servo motor of the tool changer is preferably treated as a continuous drive motor to prevent machining delays when executing a machining program that frequently performs tool changes, and is preferably treated as an intermittent drive motor to suppress energy consumption when executing a machining program that does not perform tool changes. Therefore, the motor classification unit 43 may store information specifying the classification of the continuous drive motor and the intermittent drive motor in association with the machining program.

[0022] The motor classification unit 43 may be configured to check information related to the classification of the continuous drive motor and the intermittent drive motor additionally described in the machining program. However, the motor classification unit 43 is preferably configured to classify the continuous drive motor and the intermittent drive motor by analyzing the machining content described in the machining program so that a conventional machining program without such information can be reused. Specifically, the motor classification unit 43 can be configured to classify a servo motor determined not to need to be driven for a predetermined stop period or longer in the machining program as an intermittent drive motor. Note that the "stop period" can be specified not only in units of time, but also, for example, in units of the number of blocks in the machining program. As a specific stop period, it can be set within a range such as, for example, 3 minutes or more and 10 minutes or less, 1000 blocks or more and 5000 blocks or less.

[0023] The motor classification unit 43 may be configured to check the content of the machining program in advance before the execution of the machining program and identify the intermittent drive motor. Further, the motor classification unit 43 may be configured to classify a servo motor, which is determined based on the content of the machining program pre-read by the pre-read control unit 41 not to need to be driven for a period longer than the stop period from now on, as an intermittent drive motor in order to reduce the waiting time for machining. In this case, the classification of the continuous drive motor and the intermittent drive motor may be dynamically changed during the execution of the machining program.

[0024] 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 to the servo amplifier 24 that drives the intermittent drive motor 14 not used for machining. Thereby, it is possible to suppress the power consumption while preventing the delay of machining.

[0025] The stop control unit 44 may not only stop the output of the excitation current to the servo amplifier 24 that drives the intermittent drive motor 14, but also cut off the supply of the power supply power to the servo amplifier 24, that is, open the primary breaker 241. Thereby, the power consumption can be further suppressed. The stop control unit 44 may further cut off the supply of the control power supply power to the servo amplifier 24 that drives the intermittent drive motor 14, that is, open the relay 242. Thereby, the power consumption in the control circuit of the servo amplifier 24 can also be suppressed. Note that it is preferable to perform the stop of the output of the excitation current, the cut-off of the supply of the power supply power, and the cut-off of the supply of the control power supply power in this order in order to prevent malfunction. Further, when starting the excitation of the intermittent drive motor 14, it is preferable to energize in the reverse order.

[0026] When the motor classification unit 43 dynamically classifies the intermittent drive motor based on the content of the machining program pre-read, it is preferable for the stop control unit 44 to suppress the power consumption by immediately stopping the excitation of the identified intermittent drive motor when the motor classification unit 43 identifies the intermittent drive motor.

[0027] The stop control unit 44 may, in synchronization with the excitation stop of the intermittent drive motor 14, cut off the power supply to other devices that have been previously linked to the intermittent drive motor 14. For example, when the excitation of the auxiliary motor that drives the door is stopped, the power supply to the switch for opening and closing the door, the lights that are linked to the door, etc., may be cut off.

[0028] Preferably, the stop control unit 44 is configured to excite the intermittent drive motor 14 when it determines, based on the contents of the machining program looked up by the look-ahead control unit 41, that the intermittent drive motor 14 needs to be driven within a predetermined start-up period from the present. The "start-up period" is set as a sufficient amount of time to start the intermittent drive motor 14 or the number of blocks that can secure such time. This avoids delays that would occur if the intermittent drive motor 14 were started only when its operation is required in actual machining.

[0029] The intermittent drive monitoring unit 45 checks whether the intermittent drive motor (auxiliary motor) 14 is operating unintentionally while the stop control unit has stopped exciting the intermittent drive motor 14. The intermittent drive monitoring unit 45 may be configured to monitor the detected value of the state sensor 30, and may also be configured to monitor the feedback from the encoder inside the stopped intermittent drive motor 14 if that encoder is active. This ensures the safety of the operation of the intermittent drive motor 14 even while the machine tool 1 has stopped controlling the intermittent drive motor 14.

[0030] As described above, the machine tool 1 includes a motor classification unit 43 that classifies the multiple servo motors 11, 12, 13, and 14 into continuous drive motors 11, 12, and 13 and intermittent drive motor 14, and a stop control unit 44 that stops the excitation of the intermittent drive motor 14 during the execution of the machining program. Therefore, power consumption due to the excitation of the intermittent drive motor 14 can be suppressed.

[0031] The following additional information is disclosed regarding the above embodiments and modifications. (Note 1) The machine tool (1) comprises a plurality of servo motors (11, 12, 13, 14), a plurality of servo amplifiers (21, 22, 23, 24) that drive the servo motors (11, 12, 13, 14), and a numerical control device (40) that inputs command values ​​to the plurality of servo amplifiers (21, 22, 23, 24) according to a machining program. The numerical control device (40) includes a motor classification unit (43) that classifies the plurality of servo motors (11, 12, 13, 14) into continuous drive motors (11, 12, 13) that require continuous excitation during the execution of the machining program and intermittent drive motors (14) that can be temporarily stopped from being excited during the execution of the machining program, and a stop control unit (44) that stops the excitation of at least one of the intermittent drive motors (14) during the execution of the machining program.

[0032] (Note 2) In the machine tool (1) described in Appendix 1, the stop control unit (44) may cut off the power supply to the servo amplifier (24) that drives at least one of the intermittent drive motors (14).

[0033] (Note 3) In the machine tool (1) described in Appendix 2, the stop control unit (44) may further interrupt the supply of control power to the servo amplifier (24) that drives at least one of the intermittent drive motors (14).

[0034] (Note 4) The machine tool (1) described in Appendix 1 to 3 may further include a state sensor (30) for detecting the operating state of a member driven by an intermittent drive motor (14).

[0035] (Note 5) In the machine tool (1) described in Appendix 1 to 4, the motor classification unit (43) may classify the intermittent drive motors (14) according to external input.

[0036] (Note 6) In the machine tool (1) described in Appendix 1 to 5, the motor classification unit (43) may classify servo motors (11, 12, 13, 14) that are determined not to need to be driven for a predetermined stop period or longer in the machining program as intermittent drive motors (14).

[0037] (Note 7) In the machine tool (1) of Appendix 6, the numerical control device (40) further includes a look-ahead control unit (41) that looks up the machining program and corrects the operations described in the machining program, and the motor classification unit (43) classifies servo motors (11, 12, 13, 14) that are determined not to need to be driven for more than the stop period from now as intermittent drive motors (14) based on the contents of the machining program looked up by the look-ahead control unit (41), and the stop control unit (44) may immediately stop the excitation of the identified intermittent drive motor (14) when the motor classification unit (43) has identified an intermittent drive motor (14).

[0038] (Note 8) In the machine tool (1) of Appendix 7, the stop control unit (44) may energize the intermittent drive motor (14) if it determines, based on the contents of the machining program looked up by the look-ahead control unit (41), that it is necessary to drive the intermittent drive motor (14) within a predetermined start period from the present.

[0039] (Note 9) In the machine tool (1) described in Appendix 1 to 8, the stop control unit (44) may cut off the power supply to other equipment in synchronization with the excitation stop of the intermittent drive motor (14).

[0040] Although the present disclosure has been described in detail above, this disclosure is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents.

[0041] For example, the machine tool relating to this disclosure may include other configurations independent of the stop control unit for achieving energy saving, such as activating a screen saver or turning off the power to a pump. [Explanation of Symbols]

[0042] 1 Machine tools 11, 12, 13, 14 Servo motors 21, 22, 23, 24 Servo amplifier 211, 221, 231, 241 Primary breaker 212,222,232,242 Relay 25 High-voltage power supply 26 Low-voltage power supply 30 State Sensors 40 Numerical control devices 41 Look-ahead control unit 42 Command Value Generation Unit 43 Motor Classification Section 44 Stop Control Unit 45 Intermittent drive monitoring unit

Claims

1. The system comprises a plurality of servo motors, a plurality of servo amplifiers that drive each of the servo motors, and a numerical control device that inputs command values ​​to the plurality of servo amplifiers according to a machining program. The numerical control device is A motor classification unit classifies the plurality of servo motors into continuous drive motors that require continuous excitation during the execution of the machining program and intermittent drive motors that can be temporarily stopped from being excited during the execution of the machining program. A stop control unit that stops the excitation of at least one of the intermittent drive motors during the execution of the machining program, It has, A machine tool wherein the stop control unit cuts off the supply of power and control power to the servo amplifier that drives at least one of the intermittent drive motors.

2. The machine tool according to claim 1, further comprising a state sensor for detecting the operating state of a member driven by the intermittent drive motor.

3. The machine tool according to claim 1 or 2, wherein the motor classification unit classifies the intermittent drive motors according to an external input.

4. The machine tool according to claim 1 or 2, wherein the motor classification unit classifies the servo motors that are determined not to need to be driven for a predetermined stop period or longer in the machining program as intermittent drive motors.

5. The numerical control device further includes a look-ahead control unit that looks up the machining program and corrects the operations described in the machining program, The motor classification unit classifies the servo motors that it determines do not need to be driven for longer than the stop period from the present, based on the contents of the machining program that the look-ahead control unit has looked up, into intermittent drive motors. The machine tool according to claim 4, wherein the stop control unit immediately stops the excitation of the identified intermittent drive motor when the motor classification unit identifies the identified intermittent drive motor.

6. The machine tool according to claim 5, wherein the stop control unit energizes the intermittent drive motor when it determines, based on the contents of the machining program looked up by the look-ahead control unit, that the intermittent drive motor needs to be driven within a predetermined start period from the present.

7. The machine tool according to claim 1 or 2, wherein the stop control unit cuts off the power supply to other equipment in synchronization with the excitation stop of the intermittent drive motor.

8. A machine tool comprising a plurality of servo motors, a plurality of servo amplifiers for driving each of the servo motors, and a numerical control device for inputting command values ​​to the plurality of servo amplifiers according to a machining program, The numerical control device is A motor classification unit classifies the plurality of servo motors into continuous drive motors that require continuous excitation during the execution of the machining program and intermittent drive motors that can be temporarily stopped during the execution of the machining program, according to the settings made when the machine tool was installed. A stop control unit that stops the excitation of at least one of the intermittent drive motors during the execution of the machining program, A machine tool having

9. A device comprising: a plurality of servo motors; a plurality of servo amplifiers that drive each of the servo motors; and a numerical control device that inputs command values ​​to the plurality of servo amplifiers according to a machining program, The numerical control device is A motor classification unit classifies the plurality of servo motors into continuous drive motors that require continuous excitation during the execution of the machining program and intermittent drive motors that can be temporarily stopped from being excited during the execution of the machining program. A stop control unit that stops the excitation of at least one of the intermittent drive motors during the execution of the machining program, It has, A machine tool wherein the motor classification unit stores information that identifies the classification of the continuous drive motor and the intermittent drive motor in association with the machining program.

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