Machine tool and calculation method for reduced power consumption by machine tool

Abstract

To provide a machine tool and a method for calculating the amount of reduced power consumption for the machine tool, which can accurately and easily calculate the amount of reduced power consumption.SOLUTION: An NC lathe 1 includes: an energization signal switching unit 111 that switches an energization signal set for each electrically-driven device between an energization request state that requests energization of the electrically-driven device and an energization unnecessary state that does not request energization; an inhibition signal switching unit 112 that switches an energization inhibition signal set for each electrically-driven device between an inhibition state that prohibits energization of the electrically-driven device and an authorization state that permits energization; a signal determination unit 13 that determines for each electrically-driven device whether the energization signal for the electrically-driven device is in the energization request state and the energization inhibition signal is in the inhibition state, that is, whether the electrically-driven device is in a reduced power state; and a reduction amount calculation unit 14 that calculates the amount of reduced power by finding an accumulated time of the reduced power state, calculating the amount of reduced power for each electrically-driven device based on the accumulated time, and adding up the amounts of reduced power for each device.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a machine tool including a plurality of electrically-driven devices that consume power while energized, and a method for calculating an amount of reduced power consumption of the machine tool. [Background technology]

[0002] A machine tool is equipped with various electric devices such as servo motors for moving the front headstock, front tool rest, rear headstock, and rear tool rest, as well as coolant pumps, cooling fans, product conveyors, and lighting devices. Some of these electric devices are energized and consume power not only when they are in operation but also when they are stopped. The operation of these electric devices is mainly controlled by an NC (Numerical Control) device or a PLC (Programmable Logic Controller) included in the NC device. In recent years, there has been an increasing demand to reduce the amount of power consumed by electric devices as part of measures against global warming and rising fuel costs. In response to this, a machine tool has been proposed that aims to reduce power consumption by cutting off the power supply to electric devices that do not need to operate (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5846607 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the machine tool described in Patent Document 1 has a problem in that it is not clear how much power has been reduced by cutting off the power supply to the electric equipment. As a method for solving this problem, a method is considered in which the difference between the power consumption when the machine tool is operated without cutting off the power supply and the power consumption when cutting off the power supply to the electric equipment that does not need to be operated is calculated as the reduced power amount. However, with this method, since the operation when the power supply is not cut off and the operation when the power supply is cut off are not necessarily all performed under the same conditions, there is a problem in that it is not clear whether the correct reduced power amount has been calculated. In addition, there is also a problem in that the work for calculating the reduced power amount is complicated because the machine tool must be operated without cutting off the power supply and its power consumption must be measured. In response to these problems, there is a need to develop a technology that can easily and accurately calculate the reduced power amount of the machine tool.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a machine tool and a method for calculating the amount of reduced power consumption of a machine tool that can accurately and easily calculate the amount of reduced power consumption. [Means for solving the problem]

[0006] The machine tool of the present invention which solves the above problems comprises: In a machine tool having a plurality of electrically-driven devices that consume power while energized, an energization signal switching unit that switches an energization signal set for each of the electrically-driven devices between an energization request state that requests energization of the electrically-driven devices and an energization non-request state that does not request energization; a prohibition signal switching unit that switches a current-passing prohibition signal set for each of the electrically-driven devices between a prohibition state that prohibits current from being passed to the electrically-driven device and an permission state that permits current to be passed to the electrically-driven device; a signal determination unit that determines, for each of the electrically-driven devices, whether the energization signal for the electrically-driven devices is in the energization request state and the energization prohibition signal is in the prohibition state, that is, a reduced power state; The power saving device is characterized in that it includes a reduction amount calculation unit that calculates a cumulative time of the power reduction state, calculates an amount of reduced power for each of the electrically-driven devices based on the cumulative time, and calculates the amount of reduced power by adding up the amounts of reduced power for each device.

[0007] According to this machine tool, the reduced power amount can be calculated by calculating the reduced power amount for each device based on the accumulated time and adding up the reduced power amounts for each device, so that the reduced power amount can be calculated accurately. Also, since it is not necessary to operate the machine tool in a state where power supply to the electrically-driven devices is not prohibited (cut off) in order to calculate the reduced power amount, the reduced power amount can be calculated easily.

[0008] Here, the machine tool may have an ECO mode for reducing the power consumption of the electric equipment, and may be switchable between the ECO mode and a normal mode in which the power consumption of the electric equipment is not reduced. The reduction amount calculation unit may calculate the amount of power reduction in the ECO mode. The prohibition signal switching unit may switch the power prohibition signal to a prohibited state with at least one of the conditions being that the electric equipment is a power reduction target. Furthermore, the prohibition signal switching unit may switch the power prohibition signal for the electric equipment associated with a predetermined command to a prohibited state during a predetermined period in which a processing state based on the command continues. Furthermore, the energization signal switching unit may switch the energization signal to the energization request state when a process is executed to energize the electric equipment if the electric equipment is not a power reduction target.

[0009] In this machine tool, The signal determination unit may monitor the energization signal and the energization prohibition signal to determine whether or not each of the electrically-powered devices is in the reduced power state.

[0010] This allows the signal determination unit to accurately determine whether or not the device is in the reduced power consumption state.

[0011] Here, the signal determination unit may monitor the energization signal and the energization prohibition signal at a predetermined time interval, or may constantly monitor the energization signal and the energization prohibition signal.

[0012] In this machine tool, The inhibition signal switching unit may switch the power supply inhibition signal for the electrically-powered device associated with a predetermined macro program to the inhibition state on condition that the macro program is being executed.

[0013] This makes it possible to reduce the amount of power consumed by the electrically-driven devices that do not require power supply during execution of the macro program.

[0014] In this machine tool, The motor is an electrically powered device. The inhibition signal switching unit may switch the current inhibition signal to the inhibition state in which current for exciting the motor is inhibited on condition that the motor is not rotating.

[0015] In this way, unnecessary excitation of the motor is prohibited, and the amount of power consumed by the motor can be reduced.

[0016] In this machine tool, The prohibition signal switching unit may set the current prohibition signal for the electric device to the prohibited state on condition that a product discharge operation is being performed or a tool other than a rotating tool is selected.

[0017] This makes it possible to reduce the amount of power consumed by the electrically-driven device that is not required for the product discharge operation, and the amount of power consumed by the electrically-driven device that does not require current flow when a tool other than the rotating tool is selected.

[0018] In this machine tool, A spindle having a chuck for gripping a workpiece; a spindle motor which is the electric device that rotates the main shaft, The inhibition signal switching section may set the current supply inhibition signal for the spindle motor to the inhibition state on condition that the spindle is located at a predetermined position or the chuck is released.

[0019] This reduces the power consumption of the spindle motor.

[0020] In this machine tool, a power consumption storage unit that stores an average power consumption per unit time while the electric device is energized for each of the electric devices; The reduction amount calculation unit may calculate the device-specific power reduction amount by multiplying the cumulative time by the average power consumption.

[0021] In this way, the amount of power reduction for each device can be calculated accurately.

[0022] In addition, in this machine tool, The power supply may be provided with an instantaneous reduced power display command unit that displays the power obtained by adding up the average power consumption of the electrically-driven devices that the signal determination unit has determined to be in the reduced power state among the multiple electrically-driven devices as an instantaneous reduced power.

[0023] The operator of the machine tool can recognize the instantaneous reduced power.

[0024] Furthermore, in this machine tool, The power saving device may further include an apparatus-specific reduced power amount display command unit that displays the apparatus-specific reduced power amount calculated by the reduction amount calculation unit for each electrically-powered apparatus.

[0025] The operator of this machine tool can recognize the device-specific power reduction amount for each of the electrically-driven devices.

[0026] In addition, in this machine tool, The power saving device may further include a graph display command unit for displaying the reduced power amount calculated by the reduction amount calculation unit in a graph with an axis representing the reduced power amount and an elapsed time.

[0027] The operator of this machine tool can recognize the relationship between the elapsed time and the reduced amount of power.

[0028] Here, the graph display command unit may display a time series graph showing the elapsed time from an arbitrary timing and the reduced power amount during the elapsed time.

[0029] The present invention relates to a method for calculating a reduced amount of electric power used in a machine tool, the method comprising the steps of: A method for calculating an amount of reduced power consumption of a machine tool having a plurality of electrically-driven devices that consume power while energized, comprising: an energization signal detection step of detecting whether the energization signal indicates a power supply request state that requests power supply or a power supply non-required state that does not request power supply for each of the electrically-driven devices; a prohibition signal detection step of detecting whether a current conduction prohibition signal is in a prohibition state that prohibits current conduction or in an permission state that permits current conduction for each of the electrically-driven devices; a signal determination step of determining, for each electrically-driven device, whether or not the electrically-driven signal for the electrically-driven device is in the electrically-driven request state and the electrically-driven prohibition signal is in the prohibition state, in the electrically-driven signal detection step and the prohibition signal detection step; The power reduction method further comprises a reduction amount calculation step of calculating a cumulative time of the power reduction state, calculating an amount of reduced power for each of the electrically-driven devices based on the cumulative time, and adding up the amount of reduced power for each device to calculate the amount of reduced power.

[0030] According to this method for calculating the amount of reduced power consumption for a machine tool, the amount of reduced power consumption can be calculated accurately. Moreover, since it is not necessary to operate the machine tool in a state in which power supply to the electrically-driven device is not prohibited in order to calculate the amount of reduced power consumption, the amount of reduced power consumption can be calculated easily. Moreover, even when the machine tool is operated by changing a part of an existing machining program or when the machine tool is operated by a new machining program, the amount of reduced power consumption can be calculated easily. Effect of the Invention

[0031] According to the present invention, a machine tool and a cutting method for the machine tool that can accurately and easily calculate the amount of reduced power are provided. A method for calculating the amount of power reduction can be provided. [Brief description of the drawings]

[0032] [Figure 1] FIG. 2 is a diagram showing a hardware configuration of a machine tool according to the present embodiment. [Diagram 2] FIG. 2 is a diagram showing a main functional configuration of the NC apparatus shown in FIG. [Diagram 3] 3 is a ladder diagram showing the energization operation of a coolant pump related to this embodiment among the operations of the PLC shown in FIG. 2. [Figure 4] 3 is a ladder diagram showing the energization operation of the spindle motor related to the present embodiment among the operations of the PLC shown in FIG. 2. [Diagram 5] 3 is a ladder diagram showing a current supply operation of a rotary tool motor related to this embodiment among the operations of the PLC shown in FIG. 2. [Figure 6] 3 is a flowchart showing an operation of a signal determination unit shown in FIG. 2. [Figure 7] 3 is a flowchart showing an operation of a reduction amount calculation unit shown in FIG. 2. [Figure 8] 3 is a diagram showing a display screen of the reduced power consumption and the like displayed on the display unit in response to an instruction from the display command unit shown in FIG. 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the present invention will be described by taking an example in which the present invention is applied to an NC lathe.

[0034] FIG. 1 is a diagram showing a hardware configuration of an NC lathe 1 according to this embodiment.

[0035] 1, the NC lathe 1 of this embodiment includes an NC device 2, an operation panel 3, a drive control device 4, a spindle 5, a rotary tool 6, and a coolant pump 7. The NC device 2 includes a CPU 21, a memory 22, and a timer 23. The memory 22 includes a non-volatile memory and a volatile memory. The CPU 21 temporarily stores programs and data stored in the non-volatile memory as well as data in the calculation process in the volatile memory, and executes processing by using the volatile memory as a working area.

[0036] The memory 22 stores a control program PR1, a macro program PR2, a machining program PR3, and average power consumption data AD. The control program PR1 is a basic program for executing NC control of servo motors and PLC control of various electrically powered devices. The control program PR1 also includes programs for displaying images on the display unit 32 and calculating the amount of reduced power consumption. These functions will be described in detail later.

[0037] The macro program PR2 is a program in which predetermined operations are written in advance by the manufacturer of the NC lathe 1. A plurality of macro programs PR2 are stored in the memory 22. In addition, the operator of the NC lathe 1 can also create a macro program PR2 and store it in the memory 22.

[0038] The machining program PR3 is a program also called an NC program, and is mainly created by the operator of the NC lathe 1. The machining program PR3 is a program having a code system such as G-codes representing movement commands for the headstock, tool rest, etc., T-codes representing commands for calling tools to be used, and M-codes representing commands for auxiliary functions. The NC device 2 controls the operation of the tool rest and spindle according to the machining program PR3, so that the workpiece, which is the object to be machined, is machined into a desired shape, and the machined workpiece is separated. The separated machined workpiece becomes a product manufactured by the NC lathe 1. The manufactured product is discharged to a specified position by a product discharge operation. This machining, separation, and discharge constitute one cycle, and by executing multiple cycles, the same number of products as the number of cycles are manufactured. The NC device 2 reads the machining program PR3 line by line, interprets the commands, and sequentially executes the commands described in the machining program PR3 while referring to data required for executing the commands. If the execution of a macro program PR2 is specified in the read block, the CPU 21 executes the specified macro program PR2.

[0039] The average power consumption data AD is data on the average power consumption per unit time when the coolant pump 7, the spindle motor 42, and the rotary tool motor 44 are energized. The spindle motor 42, the rotary tool motor 44, and the coolant pump 7 correspond to examples of electric devices. The NC lathe 1 is equipped with many other electric devices such as servo motors for moving the front headstock, the front tool rest, the back headstock, and the back tool rest, as well as a cooling fan, a product conveyor, a door lock switch, a spindle cooling device, and lighting equipment, but these are omitted from FIG. 1 for simplification. Hereinafter, the spindle motor 42, the rotary tool motor 44, and the coolant pump 7 are referred to as the target electric devices, and the other electric devices are referred to as the other electric devices. For the coolant pump 7, the power consumption, which is the power consumed when discharging the coolant, is stored in the memory 22 as the average power consumption data AD. On the other hand, for the spindle motor 42 and the rotary tool motor 44, the power consumption, which is the power consumed when the motor output shaft is excited to maintain a non-rotating state, is stored in the memory 22 as the average power consumption data AD. For the coolant pump 7, the average power consumption value in the average power consumption data AD is stored in the memory 22 as the catalog value of the pump. However, the coolant pump 7 may be operated to measure the power consumption of each motor using a wattmeter, and the measured value may be used as the average power consumption data AD of the coolant pump 7. For the spindle motor 42 and the rotary tool motor 44, the power consumption of each motor in a non-rotating excited state is measured using a wattmeter (not shown), and the measured value is stored in the memory 22 as the average power consumption data AD before shipping from the factory. However, for the spindle motor 42 and the rotary tool motor 44, if the power consumption of each motor in a non-rotating excited state exists as a catalog value of the motor, the catalog value may be used as the average power consumption data AD. The average power consumption data AD stored in the memory 22 can be changed as appropriate regardless of whether it is before or after shipping from the factory.

[0040] The timer 23 is used to measure the passage of time. For example, the timer 23 is used to measure the elapsed time after the power of the NC lathe 1 is turned on, and to operate the signal determination unit 13 (see FIG. 2) and the reduction amount calculation unit 14 (see FIG. 2) described later at predetermined intervals.

[0041] The operation panel 3 includes an operation unit 31 and a display unit 32. The operation unit 31 is composed of a plurality of buttons, keys, etc. that accept input operations by the operator of the NC lathe 1. The operation unit 31 may be a touch panel integrated with the display unit 32. The operator can store the machining program PR3 created using the operation unit 31 or an external computer in the memory 22. The operator can also use the operation unit 31 to modify the machining program PR3 and store the modified machining program PR3 in the memory 22. Furthermore, the operator can use the operation unit 31 to switch between an ECO mode and a normal mode, which will be described later, and select electric devices to be targeted for power reduction.

[0042] The display unit 32 is a display that displays various information related to the NC lathe 1, such as the macro program PR2, the machining program PR3, various setting values, error contents, and the amount of reduced power consumption commanded by the display command unit 15 (see FIG. 2) described later.

[0043] The drive control device 4 includes a spindle amplifier 41, a spindle motor 42, a rotary tool amplifier 43, and a rotary tool motor 44. The spindle motor 42 and the rotary tool motor 44 correspond to an example of a motor. Although not shown here for simplification, the drive control device 4 includes servo motors and servo amplifiers for moving the front headstock, the front tool rest, the back headstock, and the back tool rest for each moving axis. The spindle amplifier 41 and the spindle motor 42 in this embodiment are an amplifier and a motor for rotating the back spindle (spindle 5). The drive control device 4 also includes an amplifier and a motor for rotating the front spindle, but these are omitted here. Furthermore, the rotary tool amplifier 43 and the rotary tool motor 44 are provided for each tool rest to which the rotary tool 6 can be attached.

[0044] The spindle 5 is a part rotated by the spindle motor 42. The spindle 5 is provided on the back headstock. This spindle 5 corresponds to an example of a spindle. Note that a front spindle is provided on the front headstock, but is omitted here. The rotating tool 6 is a tool rotated by the rotating tool motor 44, and is arranged in a machining chamber where a workpiece is machined. Many NC lathes 1 are configured so that multiple rotating tools 6 can be attached to one tool rest. And, the multiple rotating tools 6 attached to one tool rest are rotated by one rotating tool motor 44. The coolant pump 7 is a pump used to circulate the coolant liquid. This coolant pump 7 discharges the coolant liquid into the machining chamber when energized.

[0045] FIG. 2 is a diagram showing a main functional configuration of the NC device 2 shown in FIG.

[0046] As shown in FIG. 2, the NC device 2 has a PLC 11, a signal judgment unit 13, a reduction amount calculation unit 14, a display command unit 15, and a graph creation unit 16 as functional configurations. These are functional configurations mainly achieved by the CPU 21 and the control program PR1 shown in FIG. 1. The PLC 11 has an energization signal switching unit 111 and a prohibition signal switching unit 112. The energization signal switching unit 111 switches the energization signal set for each target electric device provided in the NC lathe 1 (see FIG. 1) between an energization request state that requests energization for each target electric device and an energization unnecessary state that does not request energization. The PLC 11 also controls signals that switch the energization and operation of other electric devices provided in the NC lathe 1, but FIG. 2 shows only those related to this embodiment. In the normal mode, energization and de-energization of the target electric devices are controlled only by the energization signal switched by the energization signal switching unit 111. That is, when the power supply is required, the target electric device is powered, and when the power supply is not required, power supply to the target electric device is stopped. In this embodiment, the PLC 11 switches between the power supply required state and the power supply not required state by switching the signal voltage between H level and L level. However, the power supply required state and the power supply not required state may be switched by other methods. The power supply signal switching unit 111 in this embodiment includes a coolant power supply signal switching unit 111a, a spindle power supply signal switching unit 111b, and a rotating tool power supply signal switching unit 111c.

[0047] The coolant energization signal switching unit 111a switches an energization signal for the coolant pump 7 between a coolant energization request state which is a state in which energization is requested for the coolant pump 7 (see FIG. 1) and a coolant energization not required state which is a state in which energization is not required for the coolant pump 7. The spindle energization signal switching unit 111b switches an energization signal for the spindle motor 42 between a spindle energization request state which is a state in which energization is requested for the spindle motor 42 (see FIG. 1) and a spindle energization not required state which is a state in which energization is not required for the spindle motor 42. The rotating tool energization signal switching unit 111c switches an energization signal for the rotating tool motor 44 between a rotating tool energization request state which is a state in which energization is requested for the rotating tool motor 44 (see FIG. 1) and a rotating tool energization not required state which is a state in which energization is not required for the rotating tool motor 44. The energization signals switched by the coolant energization signal switching unit 111a, the spindle energization signal switching unit 111b, and the rotating tool energization signal switching unit 111c are monitored by the signal determination unit 13 at predetermined time intervals such as 8 msec or constantly. Instead of the signal determination unit 13 directly monitoring the state of the energization signal, the signal determination unit 13 may be configured to store state information of the energization signal in a predetermined area of ​​the memory 22 and acquire state information of the communication signal stored in the predetermined area. In other words, the signal determination unit 13 may indirectly monitor the state of the energization signal.

[0048] The prohibition signal switching unit 112 switches the power supply prohibition signal set for each target electric device of the NC lathe 1 (see FIG. 1) between a prohibited state that prohibits power supply to each target electric device and an permitted state that permits power supply to each target electric device. The PLC 11 of this embodiment switches between the prohibited state and the permitted state by switching the signal voltage between H level and L level. However, the prohibited state and the permitted state may be switched by other methods. The prohibition signal switching unit 112 of this embodiment includes a coolant prohibition signal switching unit 112a, a spindle prohibition signal switching unit 112b, and a rotary tool prohibition signal switching unit 112c.

[0049] The coolant inhibition signal switching unit 112a switches an electric current inhibition signal for the coolant pump 7 between a coolant inhibition state which is an inhibition state for the coolant pump 7 (see FIG. 1) and a coolant permitted state which is an permitted state for the coolant pump 7. The spindle inhibition signal switching unit 112b switches an electric current inhibition signal for the spindle motor 42 between a spindle inhibition state which is an inhibition state for the spindle motor 42 (see FIG. 1) and a spindle permitted state which is an permitted state for the spindle motor 42. The rotary tool inhibition signal switching unit 112c switches an electric current inhibition signal for the rotary tool motor 44 between a rotary tool inhibition state which is an inhibition state for the rotary tool motor 44 (see FIG. 1) and a rotary tool permitted state which is an permitted state for the rotary tool motor 44. The electric current inhibition signals switched by the coolant inhibition signal switching unit 112a, the spindle inhibition signal switching unit 112b, and the rotary tool inhibition signal switching unit 112c are monitored by the signal determination unit 13 at predetermined time intervals such as 8 msec or constantly. Instead of directly monitoring the state of the energization signal, the signal determination unit 13 may be configured to store state information of the energization prohibition signal in a predetermined area of ​​the memory 22, and the signal determination unit 13 may acquire the state information of the communication prohibition signal stored in the predetermined area. In other words, the signal determination unit 13 may indirectly monitor the state of the energization prohibition signal.

[0050] The signal determination unit 13 receives the signals switched by the energization signal switching unit 111 and the prohibition signal switching unit 112, and determines for each target electric device whether the energization signal for the target electric device is in an energization request state and the energization prohibition signal is in a prohibition state. Hereinafter, the state in which the energization signal is in an energization request state and the energization prohibition signal is in a prohibition state may be referred to as a power reduction state. The signal determination unit 13 constantly obtains information on the elapsed time since the power of the NC lathe 1 (see FIG. 1) is turned on from the timer 23. The signal determination unit 13 determines whether the target electric device is in a power reduction state, for example, every 8 msec after the power of the NC lathe 1 is turned on. The timing of this determination may be other than 8 msec, and the next determination work may be started immediately after the previous determination is completed, so that the target electric device is constantly monitored. Then, when the signal determination unit 13 determines that the target electric device is in a power reduction state, the signal determination unit 13 stores information indicating that the target electric device is in a power reduction state in the reduction time storage unit 221 provided in the memory 22. Here, the signal judgment unit 13 may compare the previous judgment result with the current judgment result, and store the changed state information in the reduction time storage unit 221 only if there is a change. In this way, the area occupied by the memory 22 for storing the judgment result can be reduced. The signal judgment unit 13 may store the judgment result in the reduction time storage unit 221 at a time interval different from the judgment time interval, for example, every minute. It is also preferable that this time interval is matched with the time interval at which the display command unit 15 updates the display of the display unit 32. In this way, it is also possible to reduce the area occupied by the memory 22 for storing the judgment result. The information stored in the reduction time storage unit 221 includes information on the elapsed time since the power supply of the NC lathe 1 was turned on. It is also possible that the signal judgment unit 13 stores information indicating that the power reduction state is not in the reduction time storage unit 221 provided in the memory 22 together with information on the elapsed time, even if the power reduction state is not in the reduction power reduction state. Furthermore, when the signal determination unit 13 determines that the power consumption is reduced, the signal determination unit 13 transmits information indicating that the power consumption is reduced to the reduction amount calculation unit 14 for each determination.

[0051] The reduction amount calculation unit 14 executes the following process every 8 msec, the same as the signal determination unit 13. First, the reduction amount calculation unit 14 accumulates the time of the reduced power state stored in the reduction time storage unit 221 for each target electric device to obtain the accumulated time of the time when each target electric device was in the reduced power state. Then, the reduction amount calculation unit 14 calculates the amount of reduced power for each device by multiplying the accumulated time by the average power consumption for each target electric device. Here, the average power consumption for each target electric device is a value obtained by referring to the average power consumption data AD (see FIG. 1). Next, the reduction amount calculation unit 14 calculates the amount of reduced power by adding up the amount of reduced power calculated for all target electric devices. Furthermore, the reduction amount calculation unit 14 calculates the instantaneous reduced power, which is the power being reduced at that time, by adding up the average power consumption of the target electric devices in the reduced power state received from the signal determination unit 13 during the past 8 msec. Thereafter, the reduction amount calculation unit 14 stores the obtained amount of reduced power for each device, the amount of reduced power, and the instantaneous reduced power in the reduction amount storage unit 223. In addition, as shown by the dashed arrow in Figure 2, the reduction amount calculation unit 14 may calculate, calculate or create only those requested by the display command unit 15 out of the reduced power amount by device, the reduced power amount, the instantaneous reduced power, and the time series graph, and store them in the reduced power amount memory unit 223.

[0052] When a request is received from the graph display command unit 153, the graph creation unit 16 creates a time series graph showing the transition of the reduced power amount with respect to the elapsed time since the power of the NC lathe 1 was turned on, using the data stored in the reduced power amount storage unit 223, with the elapsed time and the reduced power amount as axes. Then, the graph creation unit 16 stores the created time series graph in the reduced power amount storage unit 223. The graph creation unit 16 may transmit the created time series graph to the graph display command unit 153.

[0053] The display command unit 15 displays information requested by an input operation of the operation unit 31 by the operator of the NC lathe 1 on the display unit 32. The display command unit 15 has an equipment-specific reduced power display command unit 151, a reduced power display command unit 152, a graph display command unit 153, and an instantaneous reduced power display command unit 154. The equipment-specific reduced power display command unit 151 calls the equipment-specific reduced power amount stored in the reduced power amount storage unit 223 by the reduction amount calculation unit 14 and displays it on the display unit 32 for each target electric device. The reduced power amount display command unit 152 calls the reduced power amount stored in the reduced power amount storage unit 223 by the reduction amount calculation unit 14 and displays it on the display unit 32. The graph display command unit 153 calls the time series graph stored in the reduced power amount storage unit 223 by the graph creation unit 16 and displays it on the display unit 32. The graph display command unit 153 also has a function of extracting the elapsed time of a period designated by the operator and the amount of reduced power during that elapsed time from the time series graph created by the reduction amount calculation unit 14, and displaying it on the display unit 32. The instantaneous reduced power display command unit 154 calls up the instantaneous reduced power stored in the reduced power amount memory unit 223 by the reduction amount calculation unit 14, and displays it on the display unit 32.

[0054] The memory 22 has a reduction time storage section 221, a power consumption storage section 222, and a reduced power amount storage section 223. As described above, the reduction time storage section 221 stores, for each target electric device, information every 8 msec on whether or not the target electric device has been in a reduced power state since the NC lathe 1 (see FIG. 1) was powered on, in association with information on the elapsed time since the NC lathe 1 was powered on. The power consumption storage section 222 stores average power consumption data AD for each target electric device. The reduced power amount storage section 223 stores information on the reduced power amount by device, the reduced power amount, and the instantaneous reduced power calculated or computed by the reduction amount calculation section 14, as well as the time series graph created by the graph creation section 16.

[0055] FIG. 3 is a ladder diagram showing the energization operation of the coolant pump 7 related to this embodiment among the operations of the PLC 11 shown in FIG.

[0056] The contacts R20.1, R30.1, R30.2, R30.3 and α0 shown in the ladder diagram of FIG. 3 are so-called A contacts, and the contact β0 is so-called B contact. When the contact R20.1 is ON, the signal α0 is ON (H level), and when the contact R20.1 is OFF, the signal α0 is OFF (L level). This signal α0 corresponds to an example of an energization signal for the coolant pump 7. The contact R20.1 that switches ON / OFF of this signal α0 corresponds to the coolant energization signal switching unit 111a. The ON state of the signal α0 is a coolant energization request state, and the OFF state of the signal α0 is a coolant energization unnecessary state. The contact R20.1 is a contact that is ON when the command described in the machining program PR3 (see FIG. 1) is executed in sequence, if the command is a command to drive the coolant pump 7, and is OFF when the command is a command to stop driving the coolant pump 7.

[0057] Moreover, when all of the contacts R30.1, R30.2, and R30.3 are ON, the signal β0 is ON, and when any one of the contacts R30.1, R30.2, and R30.3 is OFF, the signal β0 is OFF. This signal β0 corresponds to an example of a power supply prohibition signal for the coolant pump 7. Furthermore, the contacts R30.1, R30.2, and R30.3 that switch the ON / OFF of this signal β0 correspond to the coolant prohibition signal switching unit 112a. Then, the ON of the signal β0 is a coolant prohibition state, and the OFF of the signal β0 is a coolant permission state. The contact R30.1 is ON when the ECO mode is selected, and is OFF when the normal mode is selected. The contact R30.2 is ON when the coolant pump 7 is included in the power reduction target, and is OFF when the coolant pump 7 is not included. The operator of the NC lathe 1 (see FIG. 1) can arbitrarily change whether or not the coolant pump 7 is included in the power reduction target by using the operation unit 31 (see FIG. 1). The contact R30.3 is a contact that is turned ON when the command described in the machining program PR3 (see FIG. 1) is executed in sequence and the command is a command that specifies the execution of the macro program PR2 that performs the product discharge operation, and is turned OFF when the execution of the macro program PR2 that performs the product discharge operation is completed. The operation from the start to the end of the product discharge operation corresponds to an example of a predetermined period, and whether or not the predetermined period is reached corresponds to an example of a predetermined condition that determines whether or not the prohibition signal switching unit 112 switches to a prohibited state that prohibits power supply. The coolant pump 7 is associated with the macro program PR2 that performs the product discharge operation or the command that calls the macro program PR2. When the product discharge operation is not performed by the macro program PR2, the PLC 11 determines the start and end of the product discharge operation, for example, as follows. The back spindle has an openable and closable chuck that grips the workpiece by closing it. When the PLC 11 executes a command to move the rear spindle to the first position for product discharge or a command to open the chuck holding the machined workpiece, it determines that the product discharge operation has started and turns ON contact R30.3.In addition, when the back spindle moves to a second position for gripping the product and executes a command to close the chuck that grips the workpiece, the PLC 11 determines that the product discharge operation is completed and turns off contact R30.3.

[0058] As described above, the contact α0 is an A contact, and is turned ON when the signal α0 is ON (H level), and is turned OFF when the signal α0 is OFF (L level). The contact β0 is a B contact, and is turned ON when the signal β0 is OFF (L level), and is turned OFF when the signal β0 is ON (H level). The PLC 11 turns the contact α0 ON when the signal α0 is ON, indicating a coolant current supply request state. On the other hand, the PLC 11 turns the contact α0 OFF when the signal α0 is OFF, indicating a coolant current supply unnecessary state. The process in which the PLC 11 detects the signal α0 corresponds to an example of a current supply signal detection process. The PLC 11 turns the contact β0 ON when the signal β0 is OFF, indicating a coolant permitted state. On the other hand, the PLC 11 turns the contact β0 OFF when the signal β0 is ON, indicating a coolant prohibited state. The process in which the PLC 11 detects the signal α0 corresponds to an example of a prohibition signal detection process. The PLC 11 turns the contact β0 ON when the signal β0 is OFF, indicating a coolant permitted state. On the other hand, the PLC 11 turns the contact β0 OFF when the signal β0 is ON, indicating a coolant prohibited state. The process in which the PLC 11 detects the signal β0 corresponds to an example of a prohibition signal detection process. When the contact α0 is ON and the contact β0 is ON, the signal ε0 is ON, current is supplied to the coolant pump 7 and the coolant pump 7 is driven. On the other hand, when the contact α0 is OFF or the contact β0 is OFF, the signal ε0 is OFF, current is not supplied to the coolant pump 7 and the coolant pump 7 is stopped. As described above, the state in which the signal α0 is in the coolant current request state and the signal β0 is in the coolant current prohibition state is the power reduction state of the coolant pump 7.

[0059] FIG. 4 is a ladder diagram showing the energization operation of the spindle motor 42 related to this embodiment among the operations of the PLC 11 shown in FIG.

[0060] The contacts R21.1, R31.1, R31.2, R31.3, ε1, R41.1, γ1, and α1 shown in the ladder diagram of FIG. 4 are so-called A contacts, and the contacts Δ1 and β1 are so-called B contacts. When the contact R21.1 is ON, the signal α1 is ON, and when the contact R21.1 is OFF, the signal α1 is OFF. This signal α1 corresponds to an example of an energization signal for the spindle motor 42. The contact R21.1 that switches the ON / OFF of this signal α1 corresponds to the spindle energization signal switching unit 111b. When the signal α1 is ON, it indicates a spindle energization request state, and when the signal α1 is OFF, it indicates a spindle energization not required state. Contact R21.1 is a contact that turns ON when the commands written in the machining program PR3 (see Figure 1) are executed sequentially and that turns OFF when the command is a command to excite the spindle motor 42 and a command to stop the excitation of the spindle motor 42.

[0061] Moreover, when all of the contacts R31.1, R31.2, R31.3, and Δ1 are ON, the signal β1 is ON, and when any one of the contacts R31.1, R31.2, R31.3, and Δ1 is OFF, the signal β1 is OFF. This signal β1 corresponds to an example of a current prohibition signal for the spindle motor 42. Furthermore, the contacts R31.1, R31.2, R31.3, and Δ1 that switch the ON / OFF of this signal β1 correspond to the spindle prohibition signal switching unit 112b. Then, ON of the signal β1 is a spindle prohibition state, and OFF of the signal β1α is a spindle permission state. The contact R31.1 is ON when the ECO mode is selected, and OFF when the normal mode is selected. The contact R31.2 is ON when the spindle motor 42 is included in the power reduction target, and OFF when the spindle motor 42 is not included. Whether or not the spindle motor 42 is included in the power reduction target can be arbitrarily changed by the operator of the NC lathe 1 (see FIG. 1) using the operation unit 31 (see FIG. 1). The contact R31.3 is a contact that, like the contact R30.3, turns ON when the command described in the machining program PR3 (see FIG. 1) is executed in sequence and the command is a command that specifies the execution of the macro program PR2 that performs the product discharge operation, and turns OFF when the execution of the macro program PR2 that performs the product discharge operation is completed. That is, the spindle motor 42 is associated with the macro program PR2 that performs the product discharge operation or the command that calls the macro program PR2. As described above, the spindle motor 42 here is a motor for rotating the back spindle (spindle 5 in FIG. 1) mounted on the back spindle stock. When the product discharge operation is not performed by the macro program PR2, the PLC 11 judges the start and end of the product discharge operation using a judgment method similar to that described for the contact R30.3.

[0062] Then, the PLC 11 turns on the contact α1 when the signal α1 is ON and the spindle current is requested. On the other hand, the PLC 11 turns off the contact α1 when the signal α1 is OFF and the spindle current is not required. The process of the PLC 11 detecting the signal α1 corresponds to an example of a current-signal detection process. The PLC 11 turns on the contact β1 when the signal β1 is OFF and the spindle is permitted. On the other hand, the PLC 11 turns off the contact β1 when the signal β1 is ON and the spindle is prohibited. The process of the PLC 11 detecting the signal β1 corresponds to an example of a prohibition signal detection process. When the contact α1 is ON and the contact β1 is ON, the signal ε1 turns ON, and the spindle motor 42 is energized and excited. When the spindle motor 42 is excited, the spindle motor 42 is not rotating and the output shaft does not rotate even if an external force in the rotation direction is applied (signal Δ1 described later is OFF), or the output shaft is rotating (signal Δ1 described later is ON). On the other hand, when contact α1 or contact β1 is OFF, signal ε1 is OFF, and no current is applied to the spindle motor 42, so the spindle motor 42 is not excited. When the spindle motor 42 is not excited, it is in a state where it is not rotating, and when an external force in the rotational direction is applied, the output shaft rotates. As described above, the state where signal α1 is in the spindle current request state and signal β1 is in the spindle inhibit state is the state where the spindle motor 42 is in a power reduction state.

[0063] The above-mentioned contact Δ1 is a contact that is OFF when the signal Δ1 is ON and is ON when the signal Δ1 is OFF. When the signal Δ1 is ON, the output shaft of the spindle motor 42 rotates, and when the signal Δ1 is OFF, the output shaft of the spindle motor 42 stops. That is, the signal Δ1 corresponds to the rotation signal of the spindle motor 42. The signal Δ1 is a signal that is ON when the contact γ1 is ON and is OFF when the contact γ1 is OFF. Furthermore, the contact γ1 is a contact that is ON when the signal γ1 is ON and is OFF when the signal γ1 is OFF. The signal γ1 is ON when the contact ε1 is ON and is ON when the contact R41.1 is ON, and is OFF when either the contact ε1 or the contact R41.1 is OFF. The contact ε1 is ON when the signal ε1 is ON and is OFF when the signal ε1 is OFF. Contact R41.1 is a contact that turns ON when the commands written in the machining program PR3 (see Figure 1) are executed sequentially and that turns OFF when the command is to rotate the spindle motor 42 and to stop the rotation of the spindle motor 42.

[0064] FIG. 5 is a ladder diagram showing the energization operation of the rotary tool motor 44 related to this embodiment among the operations of the PLC 11 shown in FIG.

[0065] The contacts R22.1, R32.1, R32.2, R32.3, ε2, R42.1, γ2 and α2 shown in the ladder diagram of FIG. 5 are so-called A contacts, and the contacts Δ2 and β2 are so-called B contacts. When the contact R22.1 is ON, the signal α2 is ON, and when the contact R22.1 is OFF, the signal α2 is OFF. This signal α2 corresponds to an example of an energization signal for the rotating tool motor 44. The contact R22.1 that switches ON / OFF of this signal α2 corresponds to the rotating tool energization signal switching unit 111c. When the signal α2 is ON, it indicates a rotating tool energization request state, and when the signal α2 is OFF, it indicates a rotating tool energization not required state. Contact R22.1 is a contact that is turned ON when the commands written in the machining program PR3 (see Figure 1) are executed sequentially, if the command is to excite the rotating tool motor 44, and is turned OFF when the command is to stop the excitation of the rotating tool motor 44.

[0066] Moreover, when all of the contacts R32.1, R32.2, R32.3, and Δ2 are ON, the signal β2 is ON, and when any one of the contacts R32.1, R32.2, R32.3, and Δ2 is OFF, the signal β2 is OFF. This signal β2 corresponds to an example of a power supply prohibition signal for the rotary tool motor 44. Furthermore, the contacts R32.1, R32.2, R32.3, and Δ2 that switch the ON / OFF of this signal β2 correspond to the rotary tool prohibition signal switching unit 112c. Then, the ON of the signal β2 is a rotary tool prohibition state, and the OFF of the signal β2α is a rotary tool permission state. The contact R32.1 is ON when the ECO mode is selected, and is OFF when the normal mode is selected. The contact R32.2 is ON when the rotary tool motor 44 is included in the power reduction target, and is OFF when the rotary tool motor 44 is not included. Whether or not the rotating tool motor 44 is included in the power reduction target can be arbitrarily changed by the operator of the NC lathe 1 (see FIG. 1) using the operation unit 31 (see FIG. 1). The contact R32.3 is a contact that is turned ON when the command described in the machining program PR3 (see FIG. 1) is executed in sequence and the command is a command for specifying the execution of the macro program PR2 for selecting a tool other than a rotating tool, and is turned OFF when the execution of the macro program PR2 for selecting a tool other than a rotating tool is completed. That is, the rotating tool motor 44 is associated with the macro program PR2 for selecting a tool other than a rotating tool or the command for calling the macro program PR2. Note that the end of the execution of the macro program PR2 for selecting a tool other than a rotating tool here means that the execution of the macro program PR2 for selecting a rotating tool is started. That is, the period during which the selection state of a tool other than a rotating tool continues by the execution of the macro program PR2 for selecting a tool other than a rotating tool corresponds to an example of a predetermined period, and whether or not the period is the predetermined period corresponds to an example of a predetermined condition for determining whether or not the prohibition signal switching unit 112 switches to a prohibition state for prohibiting energization.

[0067] The PLC 11 turns the contact α2 ON when the signal α2 is ON, indicating that the rotary tool is energized. On the other hand, the PLC 11 turns the contact α2 OFF when the signal α2 is OFF, indicating that the rotary tool is not energized. The process by which the PLC 11 detects the signal α2 corresponds to an example of an energization signal detection process. The PLC 11 turns the contact β2 ON when the signal β2 is OFF, indicating that the rotary tool is permitted to be used. On the other hand, the PLC 11 turns the contact β2 OFF when the signal β2 is ON, indicating that the rotary tool is prohibited to be used. The process by which the PLC 11 detects the signal β2 corresponds to an example of an inhibition signal detection process. When the contact α2 is ON and the contact β2 is ON, the signal ε2 turns ON, and the rotary tool motor 44 is energized and excited. When the rotary tool motor 44 is excited, the rotary tool motor 44 is not rotating and the output shaft does not rotate even when an external force in the rotation direction is applied (a signal Δ2 described later is OFF) or the output shaft rotates (a signal Δ2 described later is ON). On the other hand, when the contact α2 is OFF or the contact β2 is OFF, the signal ε2 is OFF, and the rotating tool motor 44 is not energized and is not excited. When the rotating tool motor 44 is not excited, it is not rotating, and when an external force in the rotation direction is applied, the output shaft rotates. As described above, the rotating tool motor 44 is in a reduced power state when the signal α2 is in the rotating tool energization request state and the signal β2 is in the rotating tool inhibition state.

[0068] The contact Δ2 described above is a contact that is OFF when the signal Δ2 is ON and is ON when the signal Δ2 is OFF. When the signal Δ2 is ON, the output shaft of the rotary tool motor 44 rotates, and when the signal Δ2 is OFF, the output shaft of the rotary tool motor 44 stops. That is, the signal Δ2 corresponds to the rotation signal of the rotary tool motor 44. The signal Δ2 is a signal that is ON when the contact γ2 is ON and is OFF when the contact γ2 is OFF. Furthermore, the contact γ2 is a contact that is ON when the signal γ2 is ON and is OFF when the signal γ2 is OFF. The signal γ2 is ON when the contact ε2 is ON and is ON and is OFF when either the contact ε2 or the contact R42.1 is OFF. The contact ε2 is ON when the signal ε2 is ON and is OFF when the signal ε2 is OFF. Contact R42.1 is a contact that is turned ON when the command written in the machining program PR3 (see Figure 1) is executed sequentially to rotate the rotating tool motor 44, and is turned OFF when the command is to stop the rotation of the rotating tool motor 44.

[0069] Fig. 6 is a flow chart showing the operation of the signal determination unit 13 shown in Fig. 2. The operation shown in Fig. 6 is executed, for example, every 8 msec after the power supply of the NC lathe 1 (see Fig. 1) is turned on.

[0070] As shown in FIG. 6, the signal determination unit 13 determines whether the signal α0 is in a coolant current request state (step S31). If the signal α0 is in a coolant current request state (YES in step S31), the signal determination unit 13 determines whether the signal β0 is in a coolant prohibition state (step S32). If the signal β0 is in a coolant prohibition state (YES in step S32), the signal determination unit 13 stores information that the coolant pump 7 is in a power reduction state in the reduction time storage unit 221 together with information on the elapsed time from when the power of the NC lathe 1 is turned on until the current determination is performed (step S33). Note that when both steps S31 and S32 are YES, the coolant pump 7 is in a power reduction state, and the coolant pump 7 is stopped while the command to drive the coolant pump 7 is still in effect. These steps S31 and S32 correspond to an example of a signal determination process. Next, the signal determination unit 13 outputs information that the coolant pump 7 is in a power reduction state to the reduction amount calculation unit 14 (step S34). If the signal α0 is not in a coolant current request state (NO in step S31), if the signal β0 is not in a coolant prohibition state (NO in step S32), or if execution of step S34 is completed, the process proceeds to step S35. Here, if the signal α0 is not in a coolant current request state (NO in step S31) or if the signal β0 is not in a coolant prohibition state (NO in step S32), the signal determination unit 13 may store information that the coolant pump 7 is not in a power reduction state together with information on the elapsed time since the NC lathe 1 was powered on in the reduction time storage unit 221, or may output the information to the reduction amount calculation unit 14.

[0071] In step S35, the signal determination unit 13 determines whether the signal α1 is in a spindle current request state. If the signal α1 is in a spindle current request state (YES in step S35), the signal determination unit 13 determines whether the signal β1 is in a spindle prohibited state (step S36). If the signal β1 is in a spindle prohibited state (YES in step S36), the signal determination unit 13 stores information that the spindle motor 42 is in a power reduction state in the reduction time storage unit 221 together with information on the elapsed time from when the power of the NC lathe 1 is turned on until the current determination is performed (step S37). Note that when both steps S35 and S36 are YES, the spindle motor 42 is in a power reduction state, and the spindle motor 42 is not excited even though the command to excite the spindle motor 42 is still in effect. These steps S35 and S36 correspond to an example of a signal determination process. Next, the signal determination unit 13 outputs information that the spindle motor 42 is in a power reduction state to the reduction amount calculation unit 14 (step S38). If the signal α1 is not in a spindle current request state (NO in step S35), if the signal β1 is not in a spindle inhibition state (NO in step S36), or if the execution of step S38 is completed, the process proceeds to step S39. Here, if the signal α1 is not in a spindle current request state (NO in step S35) or if the signal β1 is not in a spindle inhibition state (NO in step S36), the signal determination unit 13 may store information that the spindle motor 42 is not in a power reduction state in the reduction time storage unit 221 together with information on the elapsed time since the power was turned on for the NC lathe 1, or may output the information to the reduction amount calculation unit 14.

[0072] In step S39, the signal determination unit 13 determines whether the signal α2 is in a rotating tool energization request state. If the signal α2 is in a rotating tool energization request state (YES in step S39), the signal determination unit 13 determines whether the signal β2 is in a rotating tool prohibited state (step S40). If the signal β2 is in a rotating tool prohibited state (YES in step S40), the signal determination unit 13 stores information that the rotating tool motor 44 is in a reduced power state in the reduced time storage unit 221 together with information on the elapsed time from when the power of the NC lathe 1 is turned on until the current determination is performed (step S41). Note that when both steps S39 and S40 are YES, the rotating tool motor 44 is in a reduced power state, and the rotating tool motor 44 is not excited even though the command to excite the rotating tool motor 44 is still in effect. These steps S39 and S40 correspond to an example of a signal determination process. Next, the signal determination unit 13 outputs information that the rotating tool motor 44 is in a power reduction state to the reduction amount calculation unit 14 (step S42). If the signal α2 is not in a rotating tool energization request state (NO in step S39), if the signal β2 is not in a rotating tool inhibition state (NO in step S40), or if the execution of step S38 is completed, the signal determination unit 13 ends the process. Here, if the signal α2 is not in a rotating tool energization request state (NO in step S39) or if the signal β2 is not in a rotating tool inhibition state (NO in step S40), the signal determination unit 13 may store information that the rotating tool motor 44 is not in a power reduction state in the reduction time storage unit 221 together with information on the elapsed time since the power was turned on for the NC lathe 1, or may output the information to the reduction amount calculation unit 14.

[0073] Fig. 7 is a flowchart showing the operation of the reduction amount calculation unit 14 shown in Fig. 2. The operation shown in Fig. 7 is executed, for example, every 8 msec after the power of the NC lathe 1 (see Fig. 1) is turned on. However, the operation shown in Fig. 7 may be executed only when requested by the display command unit 15. Furthermore, the reduction amount calculation unit 14 may execute only the operation required for the information requested by the display command unit 15.

[0074] 7, the reduction amount calculation unit 14 obtains data on the time during which the coolant pump 7 was in the reduced power state from the reduction time storage unit 221, and obtains the average power consumption data AD of the coolant pump 7 from the power consumption storage unit 222 (step S51). Then, the reduction amount calculation unit 14 obtains an accumulated time by accumulating the time during which the coolant pump 7 was in the reduced power state, and multiplies the accumulated time by the average power consumption of the coolant pump 7 obtained from the average power consumption data AD to calculate the reduced amount of power of the coolant pump 7, and stores the reduced amount of power in the reduced power storage unit 223 (step S52).

[0075] Furthermore, reduction amount calculation unit 14 obtains data on the time during which spindle motor 42 was in the reduced power state from reduction time storage unit 221, and obtains average power consumption data AD of spindle motor 42 from power consumption storage unit 222 (step S53). Then, reduction amount calculation unit 14 obtains an accumulated time by accumulating the time during which spindle motor 42 was in the reduced power state, and multiplies the accumulated time by the average power consumption of spindle motor 42 obtained from the average power consumption data AD to calculate the reduced power amount of spindle motor 42, and stores the reduced power amount in reduced power amount storage unit 223 (step S54).

[0076] Furthermore, the reduction amount calculation unit 14 obtains data on the time during which the rotating tool motor 44 was in the reduced power state from the reduction time storage unit 221, and obtains the average power consumption data AD of the rotating tool motor 44 from the power consumption storage unit 222 (step S55). Then, the reduction amount calculation unit 14 obtains an accumulated time by accumulating the time during which the rotating tool motor 44 was in the reduced power state, multiplies the accumulated time by the average power consumption of the rotating tool motor 44 obtained from the average power consumption data AD, calculates the reduced power amount of the rotating tool motor 44, and stores the reduced power amount in the reduced power amount storage unit 223 (step S56). Each of the reduced power amount of the coolant pump 7, the reduced power amount of the spindle motor 42, and the reduced power amount of the rotating tool motor 44 corresponds to an example of the reduced power amount by device.

[0077] Next, the reduction amount calculation unit 14 calculates the amount of reduced power by adding up the calculated reduced power amount of the coolant pump 7, the reduced power amount of the spindle motor 42, and the reduced power amount of the rotary tool motor 44, and stores the amount of reduced power in the reduced power amount storage unit 223 together with the calculation time (step S57). These steps S51 to S57 are an example of a reduction amount calculation process. Furthermore, the graph creation unit 16 creates a time series graph showing the transition of the reduced power amount with respect to the elapsed time since the power of the NC lathe 1 was turned on, with the elapsed time and the reduced power amount as axes, and stores the graph in the reduced power amount storage unit 223 (step S58). This step S58 is executed by the graph creation unit 16 in response to a request from the graph display command unit 153 while the graph display command unit 153 is causing the display unit 32 to display the time series graph, but is omitted when the time series graph is not displayed. In addition, the reduction amount calculation unit 14 calculates the instantaneous reduced power, which is the power being reduced at that time, by adding up the average power consumption of the target electric devices received from the signal determination unit 13 as the target electric devices in the power reduction state during the past 8 msec. Then, the reduction amount calculation unit 14 stores the calculated instantaneous reduced power in the reduced power storage unit 223 (step S59). Here, if the reduced power storage unit 223 already has past data, the reduction amount calculation unit 14 overwrites the past data and stores the new data. Note that the reduction amount calculation unit 14 may read the past data stored in the reduced power storage unit 223 and calculate the device-specific reduced power amount and the reduced power amount by adding the information newly received from the signal determination unit 13 to the past data, or update the time series graph and store it in the reduced power storage unit 223.

[0078] FIG. 8 is a diagram showing a display screen of the reduced power consumption amount and the like displayed on the display unit 32 in response to an instruction from the display command unit 15 shown in FIG.

[0079] As described above, the display command unit 15 displays information requested by the operator of the NC lathe 1 through the input operation of the operation unit 31 on the display unit 32. FIG. 8 shows an example of a screen when the operator performs an input operation to display the reduced power amount by device, the reduced power amount, the time series graph (change in reduced power amount), and the instantaneous reduced power. These are displayed on the display unit 32 by the device-specific reduced power amount display command unit 151, the reduced power amount display command unit 152, the graph display command unit 153, and the instantaneous reduced power display command unit 154 using information stored in the reduced power amount storage unit 223 by the reduction amount calculation unit 14. While these are displayed, the displayed contents are updated as needed. By updating, the operator of the NC lathe 1 can check the reduced power amount and its change in real time. FIG. 8 shows an example of a screen in which the reduced power amount by device is arranged on the right side of the lower row, the time series graph is arranged on the left side of the lower row, the reduced power amount is arranged second from the left in the upper row, and the instantaneous reduced power is arranged at the right end of the upper row. FIG. 8 shows an example of a screen in which the power consumption amount from when the NC lathe 1 is turned on is placed at the left end of the upper row, and the power reduction rate, which is the ratio of the power consumption amount that would have been consumed in normal mode to the power reduction amount that has been reduced, is placed at the second from the right of the upper row. The time series graph shown in FIG. 8 shows the power reduction amount from when the NC lathe 1 is turned on, but only the time specified by the operator's input operation may be displayed as a time series graph. The transition of the power consumption amount may be added to the transition of the reduced power amount and displayed as a time series graph, and the time series graph of the transition of the power consumption amount and the time series graph of the transition of the reduced power amount may be made switchable. The elapsed time used as the axis of the time series graph may be changed to any unit such as seconds or hours. The elapsed time used as the axis of the time series graph may be made switchable between the elapsed time from a reference time (1 min, 2 min, etc.) and the actual time (10:00, 10:01, etc.).

[0080] In the NC lathe 1 described above, the time during which each target electric device was in a power reduction state is accumulated to obtain the cumulative time during which each target electric device was in a power reduction state, and the cumulative time is multiplied by the average power consumption to calculate the amount of power reduction for each device. The amount of power reduction is calculated by adding up the amount of power reduction for each target electric device, so that the amount of power reduction can be calculated accurately and easily. In addition, since no data is required for comparison, it is not necessary to operate the NC lathe 1 in normal mode to check the amount of power consumption. This is because the signal determination unit 13 grasps the state information of the energization request signal from the energization signal switching unit 111, and the reduction amount calculation unit 14 calculates the amount of power reduction, which is the difference between the amount of power in the normal mode and the amount of power in the ECO mode, by using the state information. In other words, it can be said that the signal determination unit 13 creates a state when the NC lathe 1 is virtually operated in the normal mode. It can also be said that the reduction amount calculation unit 14 calculates the amount of power reduction by comparing the amount of power in that state with the amount of power in the ECO mode. Therefore, even if the NC lathe 1 is operated in the ECO mode from the beginning, the amount of power reduction can be calculated.

[0081] Moreover, by setting the signals β0 and β1 to a prohibited state on the condition that the macro program PR2 for performing the product discharge operation is being executed, the supply of current to the coolant pump 7 and the spindle motor 42 is cut off to prevent unnecessary power consumption. Similarly, by setting the signal β2 to a prohibited state on the condition that the macro program PR2 for selecting a tool other than a rotating tool is being executed, the supply of current to the rotating tool motor 44 is cut off to prevent unnecessary power consumption. Furthermore, by displaying the instantaneous reduced power, the operator of the NC lathe 1 can recognize the instantaneous reduced power, which is essentially the reduced power at that moment. Furthermore, by displaying the reduced power amount by device, the operator can recognize the reduced power amount by device, which is the reduced power amount for each target electric device. Furthermore, by displaying a time series graph, the operator can recognize the relationship between the elapsed time and the reduced power amount.

[0082] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the claims. For example, in the present embodiment, the present invention is applied to the NC lathe 1, but the present invention may be applied to other machine tools such as a machining center or a milling machine. In the present embodiment, the spindle motor 42, the rotary tool motor 44, and the coolant pump 7 are used as the target electric devices to calculate the reduced power amount. However, instead of a part or all of these, other electric devices may be used as the target electric devices to calculate the reduced power amount. In addition, other electric devices may be added in addition to the target electric devices in the present embodiment to calculate the reduced power amount. In addition, the switching conditions between the energization request state and the energization unnecessary state and the switching conditions between the prohibited state and the permitted state may be changed as appropriate. Furthermore, the NC lathe 1 of the present embodiment is capable of switching between the ECO mode and the normal mode, but the ECO mode may always be selected without switching.

[0083] Even if a constituent element is included only in the description of each of the modified examples described above, that constituent element may be applied to other modified examples. [Explanation of symbols]

[0084] 1 NC lathe (machine tool) 13 Signal Judgment Section 14 Reduction amount calculation section 111 Power signal switching unit 112 Prohibition signal switching section

Claims

1. In a machine tool having a plurality of electrically-driven devices that consume power while energized, an energization signal switching unit that switches an energization signal set for each of the electrically-driven devices between an energization request state that requests energization of the electrically-driven devices and an energization non-request state that does not request energization; a prohibition signal switching unit that switches a current-passing prohibition signal set for each of the electrically-driven devices between a prohibition state that prohibits current from being passed to the electrically-driven device and an permission state that permits current to be passed to the electrically-driven device; a signal determination unit that determines, for each of the electrically-driven devices, whether the energization signal for the electrically-driven devices is in the energization request state and the energization prohibition signal is in the prohibition state, that is, a reduced power state; a reduction amount calculation unit that calculates a cumulative time of the power reduction state, calculates an amount of reduced power for each of the electrically-driven devices based on the cumulative time, and calculates an amount of reduced power by adding up the amounts of reduced power for each device.

2. 2. The machine tool according to claim 1, wherein the signal determination unit monitors the energization signal and the energization prohibition signal to determine whether or not each of the electrically-driven devices is in the reduced power state.

3. The machine tool according to claim 1, characterized in that the prohibition signal switching unit switches the power supply prohibition signal for the electric equipment associated with a macro program to the prohibited state on the condition that a predetermined macro program is being executed.

4. The motor is an electrically powered device.

2. The machine tool according to claim 1, wherein the inhibition signal switching unit switches the current inhibition signal to the inhibition state in which current to excite the motor is inhibited on the condition that the motor is not rotating.

5. The machine tool according to claim 1, characterized in that the prohibition signal switching unit sets the power supply prohibition signal to the electric equipment to the prohibited state under the condition that a product discharge operation is being performed or a tool other than a rotating tool is selected.

6. A spindle having a chuck for gripping a workpiece; a spindle motor which is the electric device that rotates the main shaft, 2. The machine tool according to claim 1, wherein the inhibition signal switching unit sets the current supply inhibition signal for the spindle motor to the inhibition state on condition that the spindle is located at a predetermined position or the chuck is released.

7. a power consumption storage unit that stores an average power consumption per unit time while the electric device is energized for each of the electric devices; 2. The machine tool according to claim 1, wherein the reduction amount calculation unit calculates the amount of power reduction for each device by multiplying the accumulated time by the average power consumption.

8. The machine tool according to claim 7, further comprising an instantaneous reduced power display command unit that displays as instantaneous reduced power the power obtained by adding up the average power consumption of the electric devices among the plurality of electric devices that the signal determination unit has determined to be in the reduced power state.

9. A machine tool according to any one of claims 1 to 7, further comprising an equipment-specific reduced power amount display command unit that displays the equipment-specific reduced power amount calculated by the reduction amount calculation unit for each electrically-driven device.

10. 8. A machine tool according to claim 1, further comprising a graph display command unit for displaying the reduced power amount calculated by the reduction amount calculation unit on a graph with elapsed time as an axis.

11. A method for calculating an amount of reduced power consumption of a machine tool having a plurality of electrically-driven devices that consume power while energized, comprising: an energization signal detection step of detecting whether the energization signal indicates a power supply request state that requests power supply or a power supply non-required state that does not request power supply for each of the electrically-driven devices; a prohibition signal detection step of detecting whether a current conduction prohibition signal is in a prohibition state that prohibits current conduction or in an permission state that permits current conduction for each of the electrically-driven devices; a signal determination step of determining, for each electrically-driven device, whether or not the electrically-driven signal for the electrically-driven device is in the electrically-driven request state and the electrically-driven prohibition signal is in the prohibition state, in the electrically-driven signal detection step and the prohibition signal detection step; and a reduction amount calculation step of determining an accumulated time of the reduced power state, calculating an amount of reduced power for each of the electrically-driven devices based on the accumulated time, and adding up the amount of reduced power for each device to calculate the amount of reduced power.

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