Working machinery

Abstract

A machine tool according to one aspect of the present disclosure is provided with: a plurality of servo motors; a plurality of servo amplifiers that respectively drive the servo motors; and a control device that inputs a command value to the plurality of servo amplifiers according to a machining program, wherein the control device has a safety information acquisition unit that acquires safety information indicating the safety on excitation stop of the servo motors, and a stop control unit that, when the machining program is not running, stops the excitation of the servo motors indicated to be safe by the safety information.

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 to it one by 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 the movable limit) when a power failure occurs or the like, a technique has been proposed to cut off the power supply to the servo motor 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 saving has been increasing, and further energy saving 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 control device that inputs command values ​​to the plurality of servo amplifiers according to a machining program, wherein the control device includes a safety information acquisition unit that acquires safety information indicating the safety of stopping the excitation of the servo motors, and a stop control unit that stops the excitation of the servo motors that the safety information indicates are safe when the machining program is not being executed. [Brief explanation of the drawing]

[0007] [Figure 1] This is a block 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, one or more auxiliary devices 30 that are not servo-driven, driven members 41, 42, 43, 44, 45 that are driven by the servo motors 11, 12, 13, 14 or the auxiliary devices 30 respectively, a plurality of state sensors 51, 52, 53, 54, 55, 56 that detect safety against excitation stoppage of the servo motors 11, 12, 13, 14, and a control device 60 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 may include a spindle motor that rotates the tool and workpiece relative to each other, multiple positioning axis motors that move the tool and workpiece relative to each other, and servo motors that drive peripheral devices such as doors. 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] 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 control device 60.

[0012] The servo amplifiers 21, 22, 23, and 24 are each supplied with power from the power supply unit 25. The circuits supplying power from the power supply unit 25 to the servo amplifiers 21, 22, 23, and 24 may be provided with primary breakers 211, 221, 231, and 241, which are operated by the control device 60.

[0013] 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 control device 60. 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.

[0014] Furthermore, the servo amplifiers 21, 22, 23, and 24 may be configured to stop communication according to the value of the communication control signal input from the control device 60, and it is preferable that they are configured to reduce the communication speed according to the communication control signal input from the control device 60.

[0015] The auxiliary devices 30 are, for example, one or more power-consuming devices such as a door opening / closing motor that is not servo-driven, a hydraulic pump, a cooling fan, a refrigerator, an air compressor, lighting, and a display device. The auxiliary devices 30 can be controlled by the control device 60 via, for example, a relay circuit (not shown).

[0016] The driven members 41, 42, 43, 44, and 45 are driven by servo motors 11, 12, 13, and 14 or ancillary devices 30. Specific examples of the driven members 41, 42, 43, 44, and 45 include tool chucks, workpiece holding tables, and door panels. Furthermore, the driven members 41, 42, 43, 44, and 45 may include other servo motors 11, 12, 13, and 14 for multi-axis positioning.

[0017] The state sensors 51, 52, 53, 54, 55, and 56 may be configured to detect the operating state (position, orientation, etc.) of the driven members 41, 42, 43, 44, and 45, or a manually operated safety cover. The state sensors 51, 52, 53, 54, 55, and 56 may also be sensors that confirm the absence of people or objects in a particular space. The state sensors 51, 52, 53, 54, 55, and 56 may be, for example, photoelectric tubes, limit switches, etc.

[0018] The control device 60 can be implemented by one or more computer devices that include, for example, memory, a processor (CPU), an input / output interface, a display, etc., and execute an appropriate control program. Specifically, the control device 60 may be, for example, a numerical control device, a programmable logic controller, a personal computer, etc. The control device 60 includes a command value generation unit 61, a safety information acquisition unit 62, a stop control unit 63, a restart control unit 64, and an activation setting unit 65. These components of the control device 60 are classifications of the functions of the control device 60 and do not necessarily need to be clearly distinguishable in terms of physical configuration and program configuration.

[0019] The command value generation unit 61 generates command values ​​to be input to the servo amplifiers 21, 22, 23, and 24 based on the machining program. The command value generation unit 61 may be configured to correct the command values ​​to be input to the servo amplifiers 21, 22, 23, and 24, taking into account feedback signals indicating the actual speed of the servo motors 11, 12, 13, and 14.

[0020] The safety information acquisition unit 62 acquires one or more safety information indicating the safety of stopping the excitation of the servo motors 11, 12, 13, and 14. Each safety information indicates the safety of one or more servo motors 11, 12, 13, and 14, and multiple safety information may indicate the safety of the same servo motor 11, 12, 13, and 14. If multiple safety information indicates the safety of the same servo motor 11, 12, 13, and 14, safety can be guaranteed even if the excitation of the corresponding servo motor 11, 12, 13, and 14 is stopped when all safety information values ​​indicate safety. "Safety against stopping excitation" means that no harm is expected even if the driven members 41, 42, 43, and 44 descend due to the loss of torque against gravity, or if the driven members 41, 42, 43, and 44 overshoot due to the loss of braking force. The safety information preferably includes detection values ​​from state sensors 51, 52, 53, 54, 55, and 56, and may further include encoder information for servo motors 11, 12, 13, and 14, brake operation information for servo motors 11, 12, 13, and 14 that have brakes, and the status of manual switches operated by the user.

[0021] The stop control unit 63 stops the excitation of servo motors 11, 12, 13, and 14 that are deemed safe by safety information when the machining program is not being executed. In other words, the stop control unit 63 stops the output of excitation current to the servo amplifiers 21, 22, 23, and 24 that drive servo motors 11, 12, 13, and 14, which are determined to be safe to do so based on safety information. This reduces the power consumption of servo motors 11, 12, 13, and 14 when the machining program is not being executed.

[0022] When the stop control unit 63 stops the excitation of the servo motors 11, 12, 13, and 14, it is preferable to display that the excitation is stopped so that the user can confirm the stop of the excitation.

[0023] The stop control unit 63 not only stops the output of the excitation current to the servo amplifiers 21, 22, 23, and 24 that drive the servo motors 11, 12, 13, and 14, but may also cut off the power supply to the servo amplifiers 21, 22, 23, and 24, that is, open the primary breakers 211, 221, 231, and 241. Thereby, the power consumption can be further suppressed.

[0024] The stop control unit 63 may stop the communication of the servo amplifiers 21, 22, 23, and 24 that drive the servo motors 11, 12, 13, and 14 indicating safety or reduce the communication speed when the safety information indicates safety. Thereby, the power for the communication of the servo amplifiers 21, 22, 23, and 24 can also be suppressed.

[0025] The stop control unit 63 may cut off the power supply to the accessory device 30 linked to the servo motors 11, 12, 13, and 14 in advance in synchronization with the stop of the excitation of the servo motors 11, 12, 13, and 14. Examples of the device that can cut off the power supply in synchronization with the servo motors 11, 12, and 13, and 14 include a display device that displays information on the servo motors 11, 12, 13, and 14, lighting for improving the visibility of the servo motors 11, 12, 13, and 14, the driven members 41, 42, 43, 44, 45, etc., and a cooling fan that cools the servo motors 11, 12, 13, and 14.

[0026] The restart control unit 64 monitors the detection values of the state sensors 51, 52, 53, 54, 55, and 56 while the stop control unit 63 stops the excitation of the servo motors 11, 12, 13, and 14. When it is determined based on the detection values of the state sensors 51, 52, 53, 54, 55, and 56 that the stop of the excitation of the servo motors 11, 12, 13, and 14 may cause harm, the restart control unit 64 causes the stop control unit 63 to restart the excitation of the servo motors 11, 12, 13, and 14.

[0027] The activation setting unit 65 activates or deactivates the stop control unit 63 according to an external signal. If the machining program is started while the stop control unit 63 has stopped the excitation of the servo motors 11, 12, 13, and 14, there may be a waiting time required to restart the excitation of the servo motors 11, 12, 13, and 14. Therefore, if the execution interval of the machining program is short, a decrease in operating efficiency can be prevented by deactivating the stop control unit 63 using an external signal, for example, from a management computer.

[0028] As described above, the machine tool 1 is equipped with a stop control unit 63 that stops the excitation of the servo motors 11, 12, 13, and 14 when the machining program is not being executed, thereby suppressing the power consumption caused by the excitation of the servo motors 11, 12, 13, and 14.

[0029] 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 control device (60) that inputs command values ​​to the plurality of servo amplifiers (21, 22, 23, 24) according to a machining program. The control device (60) includes a safety information acquisition unit (62) that acquires safety information indicating the safety of stopping the excitation of the servo motors (11, 12, 13, 14), and a stop control unit (63) that stops the excitation of the servo motors (11, 12, 13, 14) for which the safety information indicates safety when the machining program is not being executed.

[0030] (Note 2) The stop control unit (63) may cut off the power supply to the servo amplifiers (21, 22, 23, 24) that drive the servo motors (11, 12, 13, 14) for which safety information indicates safety.

[0031] (Note 3) The stop control unit (63) may stop or reduce the communication speed of the servo amplifiers (21, 22, 23, 24) that drive the servo motors (11, 12, 13, 14) for which safety information indicates safety.

[0032] (Note 4) The machine tool (1) may further include state sensors (51, 52, 53, 54) for detecting the operating state of members (41, 42, 43, 44) driven by servo motors (11, 12, 13, 14).

[0033] (Note 5) The control device (60) may further include a restart control unit (64) that restarts the excitation of the servo motors (11, 12, 13, 14) based on the detected values ​​of the state sensors (51, 52, 53, 54).

[0034] (Note 6) The control device (60) may further include an activation setting unit (65) that activates or deactivates the stop control unit (63) according to an external signal.

[0035] (Note 7) The stop control unit (63) may indicate that the servo motors (11, 12, 13, 14) are stopped when the excitation of them is stopped.

[0036] (Note 8) The stop control unit (63) may shut off the power supply to other devices (30) in synchronization with the excitation stop of the servo motors (11, 12, 13, 14).

[0037] 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.

[0038] For example, in the machine tool relating to this disclosure, auxiliary equipment is not mandatory, and a state sensor for detecting the operating state of a driven member not driven by a servo motor is also an optional configuration. Furthermore, the machine tool relating to this disclosure may include other configurations independent of the stop control unit to achieve energy saving, such as activating a screen saver or turning off the pump power. [Explanation of Symbols]

[0039] 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 Power supply 30 Ancillary equipment 41, 42, 43, 44, 45 Driven members 51, 52, 53, 54, 55, 56 State Sensors 60 Control device 61 Command Value Generation Unit 62 Safety Information Acquisition Department 63 Stop control unit 64 Restart Control Unit 65 Activation Settings Section

Claims

1. The system comprises a plurality of servo motors, a plurality of servo amplifiers that drive each of the servo motors, and a control device that inputs command values ​​to the plurality of servo amplifiers according to a machining program. The control device is A safety information acquisition unit acquires safety information indicating the safety of stopping the excitation of the servo motor, When the aforementioned machining program is not being executed, a stop control unit stops the excitation of the servo motor that the safety information indicates is safe, and stops or reduces the communication speed of the servo amplifier that drives the servo motor that the safety information indicates is safe. A machine tool having

2. The machine tool according to claim 1, wherein the stop control unit cuts off the power supply to the servo amplifier that drives the servo motor in which the safety information indicates safety.

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

4. The machine tool according to claim 3, wherein the control device further comprises a restart control unit that restarts the excitation of the servo motor based on the value detected by the state sensor.

5. The machine tool according to claim 1 or 2, wherein the control device further comprises an activation setting unit that activates or deactivates the stop control unit according to an external signal.

6. The machine tool according to claim 1 or 2, wherein the stop control unit indicates that the servo motor is stopped when the excitation of the servo motor is stopped.

7. The machine tool according to claim 1 or 2, wherein the stop control unit shuts off the power supply to other devices in synchronization with the excitation stop of the servo motor.

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