Machine tool and tank

Abstract

To provide an art for dealing with a foam coolant occurring in various positions.SOLUTION: A machine tool may process a workpiece and includes: a first tank for storing a coolant used in machining the workpiece; a pump for pumping up the coolant stored in the first tank; a second tank for storing the coolant pumped up by the pump; and a controller for controlling the pump to send bubbles generated inside the first tank together with the coolant, to the second tank.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a machine tool and a tank.

Background Art

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2005-177900) discloses a machine tool equipped with a chip conveyor. The chip conveyor is a transport mechanism for discharging chips of a workpiece generated during machining outside the machine tool. The chips are flowed from the machining area to the chip conveyor by a coolant.

[0003] A filtration drum is provided inside the chip conveyor disclosed in Patent Document 1. The filtration drum is configured to remove chips of the workpiece from the coolant flowing into the filtration drum from the outside to the inside.

[0004] In addition, a plurality of coolant injection mechanisms are provided inside the filtration drum. Each injection mechanism injects a cleaning coolant from the inside of the filtration drum toward the filter on the outer peripheral surface to blow off the chips clogged in the filter. As a result, the filtration drum is backwashed, and the filtration drum is prevented from being clogged with chips. The filtration drum disclosed in Patent Document 1 suppresses foaming generated during backwashing by ejecting the coolant ejected from each injection mechanism without interfering with each other.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When the coolant foams, it may leak outside the machine tool. Such foaming of the coolant can occur not only during backwashing of the filter drum but also in various places. When the coolant foams in various places, it is difficult to suppress the foaming itself. Therefore, a technique for dealing with the foamy coolant generated in various places is desired.

Means for Solving the Problems

[0007] In an example of the present disclosure, a machine tool capable of machining a workpiece is provided. The machine tool includes a first tank for storing the coolant used for machining the workpiece, a pump for pumping up the coolant stored in the first tank, a second tank for storing the coolant pumped up by the pump, and a control device for controlling the pump so as to send the foam and the coolant generated inside the first tank to the second tank. Execute the process.

[0008] In an example of the present disclosure, the machine tool further includes a filter mechanism provided inside the first tank for removing foreign matters contained in the coolant.

[0009] In an example of the present disclosure, the filter mechanism is a drum filter configured to remove the foreign matters from the coolant flowing from the outside to the inside.

[0010] In an example of the present disclosure, the process of controlling includes controlling the pump so that the liquid level of the liquid coolant stored inside the first tank passes through the suction port of the pump.

[0011] In an example of the present disclosure, the machine tool includes a sensor for detecting the height of the upper surface of the foamy coolant stored in the second tank. The control device executes a predetermined abnormality countermeasure process based on the fact that the height of the upper surface of the foamy coolant has reached a predetermined threshold value.

[0012] In one example of the present disclosure, the machine tool further includes a float-type pump configured to float on the liquid coolant stored inside the second tank.

[0013] In another example of the present disclosure, a tank capable of storing the coolant used for machining the workpiece by the machine tool is provided. The machine tool includes a pump for pumping up the coolant stored in the tank and another tank for storing the coolant pumped up by the pump. The tank is configured such that when the pump is controlled, the bubbles and the coolant generated inside the tank are sent to the other tank.

[0014] In another example of the present disclosure, a tank used in a machine tool is provided. The machine tool includes another tank for storing the coolant used for machining the workpiece and a pump for sending the coolant stored in the other tank to the tank. The tank is configured such that when the pump is controlled, the bubbles and the coolant generated inside the other tank are sent.

[0015] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention understood in connection with the accompanying drawings.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0017] Hereinafter, each embodiment according to the present invention will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

[0018] <A. Appearance of Machine Tool 100> First, with reference to FIG. 1, a machine tool 100 according to an embodiment will be described. FIG. 1 is a diagram showing the appearance of the machine tool 100.

[0019] As used in this specification, the “machine tool” is a concept encompassing various devices having a function of processing a workpiece. The machine tool 100 may be a horizontal machining center, or may be a vertical machining center. Alternatively, the machine tool 100 may be a lathe, or may be other cutting machines, grinding machines, multi-tasking machines, 5-axis machining machines, etc. Further, the machine tool 100 is not limited to performing only removal machining, and may perform addition machining in addition to removal machining.

[0020] The machine tool 100 includes, for example, a cover body 130, a chip conveyor 150, and an operation panel 300. The cover body 130, also called a splash guard, forms the appearance of the machine tool 100 and partitions the machining area AR of the workpiece.

[0021] The machine tool 100 processes the workpiece while discharging coolant into the machining area AR. The coolant used in the machining causes the chips of the workpiece to flow from the machining area AR to the chip conveyor 150. The chip conveyor 150 separates the chips of the workpiece from the coolant and discharges the chips outside the machine tool 100 through the discharge port 27. The coolant from which the chips of the workpiece have been removed is reused for machining the workpiece. Details of the chip conveyor 150 will be described later.

[0022] The operation panel 300 is a general-purpose computer and has a display 306 for displaying various information related to machining. The display 306 is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or other display device. Further, the display 306 is provided with a touch panel and accepts various operations on the machine tool 100 by touch operation.

[0023] <B. Collection mechanism for foamy coolant> The machine tool 100 processes the workpiece while discharging coolant into the machining area AR. At this time, the coolant foams due to various factors. As an example, the coolant becomes foamy when discharged onto the wall or the workpiece, or becomes foamy during the process of flowing inside the machine. Such foaming of the coolant can occur in various places. Therefore, the machine tool 100 according to the embodiment has a mechanism for collecting the foamy coolant in one place.

[0024] FIG. 2 is a conceptual diagram schematically showing the collection mechanism for foamy coolant. As shown in FIG. 2, the machine tool 100 includes the above-described machining area AR, a tank 11 (first tank), a tank 12 (second tank), a control device 50, and pumps 152 and 160.

[0025] The tank 11 is configured to store the coolant used for machining the workpiece. Since the coolant foams during machining of the workpiece, not only the liquid coolant CLL but also the foamy coolant CLB accumulates in the tank 11.

[0026] The pump 152 is provided inside the tank 11 and is configured to pump up the coolant stored in the tank 11. The coolant pumped up by the pump 152 is sent to the tank 12. The tank 12 is configured to store the coolant sent from the tank 11.

[0027] The control device 50 is a device for controlling the machine tool 100. The control device 50 controls the pump 152 so as to send the foamy coolant CLB generated inside the tank 11 to the tank 12. As a result, the foamy coolant CLB is collected in the tank 12. Therefore, the operator only needs to deal with the foamy coolant CLB in the tank 12 in order to prevent the foamy coolant from leaking outside the machine tool 100. The operator can, for example, make the foamy coolant CLB disappear by adding an antifoaming agent into the tank 12.

[0028] Preferably, the machine tool 100 controls the pump 152 so that the liquid level LS of the liquid coolant CLL stored inside the tank 11 passes through the suction port SP of the pump 152. The liquid level LS corresponds to the interface between the liquid coolant CLL and the foamy coolant CLB.

[0029] Note that the control device 50 may control the pump 152 so that the liquid level LS changes from the upper side to the lower side of the suction port SP, or may control the pump 152 so that the liquid level LS changes from the lower side to the upper side of the suction port SP. In the example of FIG. 2, the control device 50 controls the pump 152 so that the liquid level LS changes from the upper side to the lower side of the suction port SP.

[0030] When the liquid level LS of the liquid coolant CLL passes through the suction port SP of the pump 152, the foamy coolant CLB floating on the liquid coolant CLL is sucked in from the suction port SP. As a result, the foamy coolant CLB is surely sent from the tank 11 to the tank 12.

[0031] In addition, when the machine tool 100 is provided with only one tank 11, if the liquid level LS of the liquid coolant CLL is below the suction port SP, the liquid coolant CLL will not be supplied to the machining area AR. In this case, it is necessary to stop the machining of the workpiece.

[0032] On the other hand, by providing two tanks 11 and 12 in the machine tool 100, even if the liquid level LS of the liquid coolant CLL is below the suction port SP, the machine tool 100 can continue to supply the liquid coolant CLL from the tank 12 to the machining area AR. Therefore, the machine tool 100 can concentrate the foamed coolant CLB in the tank 12 while continuously supplying the coolant to the machining area AR.

[0033] <C. Configuration of Chip Conveyor 150> Next, with reference to FIGS. 3 and 4, the chip conveyor 150 shown in FIG. 1 described above will be explained. FIG. 3 is a view showing the appearance of the chip conveyor 150. FIG. 4 is a view showing a cross section of the chip conveyor 150.

[0034] The chip conveyor 150 is provided, for example, in a cover body 130 that partitions the machining area. The chip conveyor 150 receives the chips and coolant of the workpiece discharged from the machining area.

[0035] The chip conveyor 150 has the above-described tank 11. The tank 11 is configured to be able to store the coolant. The chip conveyor 150 conveys the chips of the workpiece contained in the coolant to a chip bucket (not shown) and discharges the clean coolant to the tank 11 by filtering the coolant.

[0036] The chip conveyor 150 further has a cover body 21. The cover body 21 forms the appearance of the chip conveyor 150. The cover body 21 has a housing shape that forms a space inside.

[0037] The cover body 21 has, as its constituent parts, a horizontal part 22, a chip receiving part 23, a rising part 26, and a discharge port 27.

[0038] The horizontal part 22 is placed inside the tank 11. The horizontal part 22 has an appearance in the shape of a plate extending in the horizontal direction. The rising part 26 rises from one end in the longitudinal direction of the horizontal part 22 and extends obliquely upward.

[0039] The chip receiving part 23 is provided on the horizontal part 22. The chip receiving part 23 is composed of a housing provided on the top surface of the horizontal part 22. A connection port 24 is provided in the chip receiving part 23. The connection port 24 consists of a through hole penetrating the chip receiving part 23. A chip conveying device 13 is connected to the chip receiving part 23 through the connection port 24. The chip conveying device 13 includes, for example, a trough extending in one direction and a spiral conveyor installed in the trough.

[0040] The discharge port 27 is provided at the end of the rising part 26 extending obliquely upward from the horizontal part 22. The discharge port 27 consists of an opening of the cover body 21 opening vertically downward. Below the discharge port 27, a chip bucket (not shown) for collecting chips is installed. The chips of the workpiece discharged from the processing area are received into the cover body 21 from the chip receiving part 23. The chips are subsequently conveyed inside the cover body 21 by the chip conveying mechanism described below, discharged from the discharge port 27, and collected in the chip bucket.

[0041] The chip conveyor 150 further has a chip conveying part 35. The chip conveying part 35 is housed in the cover body 21. The chip conveying part 35 is a device for conveying chips inside the cover body 21.

[0042] More specifically, the chip conveying part 35 has a pair of endless chains 34, a driving sprocket 37, and a driven sprocket 38.

[0043] The drive sprocket 37 is provided at the end of the rising portion 26 that extends obliquely upward from the horizontal portion 22. The drive sprocket 37 is disposed above the discharge port 27. The drive sprocket 37 is rotatably supported about an axis extending in a direction orthogonal to the plane of FIG. 4 (hereinafter, this direction is also referred to as the "width direction of the chip conveyor 150"). An output shaft of a motor MD (see FIG. 8), which will be described later, is connected to the drive sprocket 37. The drive sprocket 37 rotates when power is transmitted from the motor MD.

[0044] The driven sprocket 38 is provided at the bent portion between the horizontal portion 22 and the rising portion 26. The driven sprocket 38 is rotatably supported about an axis (axis AX1) extending in the width direction of the chip conveyor 150.

[0045] A pair of endless chains 34 are arranged in parallel at a distance in the width direction of the chip conveyor 150. The endless chains 34 are looped around the drive sprocket 37 and the driven sprocket 38 and are guided by a plurality of guide members. When the drive sprocket 37 rotates, the endless chains 34 rotate in the direction indicated by arrow A (hatched arrow) in FIG. 4.

[0046] The chip conveyor 150 further has a filter mechanism 39. The filter mechanism 39 is provided inside the tank 11 and removes foreign matters such as chips of the workpiece from the coolant that has flowed into the tank 11 from the processing area. Thereby, the coolant received from the processing area is filtered, and the clean coolant is discharged from inside the cover body 21 into the tank 11.

[0047] The filter mechanism 39 has, for example, a drum filter 46. The drum filter 46 is housed in the cover body 21. The drum filter 46 is provided at the bent portion between the horizontal portion 22 and the rising portion 26. The drum filter 46 is configured to remove foreign matters such as chips from the coolant flowing in from the outside to the inside. The drum filter 46 has, for example, a cylindrical shape and forms an internal space 47 inside thereof.

[0048] The drum filter 46 is arranged such that its central axis extends in the width direction of the chip conveyor 150. The drum filter 46 is arranged such that its central axis coincides with the axis AX1 which is the rotation center of the driven sprocket 38. The drum filter 46 is connected to the driven sprocket 38 at both ends in the axial direction of the axis AX1.

[0049] In the above description, an example in which the filter mechanism 39 has the drum filter 46 has been described, but the filter mechanism 39 is not limited to the drum filter 46. As an example, the filter mechanism 39 may be composed of a rectangular filter or a circular filter.

[0050] A coolant discharge portion 28 is formed in the cover body 21. The coolant discharge portion 28 is composed of a through hole penetrating the cover body 21. The coolant discharge portion 28 is provided so as to communicate the internal space 47 of the drum filter 46 with the external space outside the cover body 21. The coolant received into the cover body 21 through the chip receiving portion 23 enters the internal space 47 of the drum filter 46 and is filtered. The filtered coolant is discharged to the tank 11 through the coolant discharge portion 28.

[0051] <D. Coolant Circulation Mechanism> Next, with reference to FIG. 5, the coolant circulation mechanism will be described. FIG. 5 is a diagram showing an example of the coolant circulation mechanism.

[0052] The machine tool 100 includes, as a configuration of a coolant circulation mechanism, a tank 11, a tank 12, a discharge unit 125, a chip conveyor 150, a water level sensor 151, a pump 152, a water level sensor 155, a pump 160, and flow paths R1, R2A to R2C, R3.

[0053] The discharge unit 125 is provided inside the machining area AR and discharges coolant to the workpiece and the machining area AR. As a result, the discharge unit 125 discharges the chips generated by machining the workpiece to the chip conveyor 150. The discharge unit 125 is composed of one or more discharge mechanisms. In the example of FIG. 5, the discharge unit 125 is composed of discharge mechanisms 125A to 125C.

[0054] Coolant is stored in the tank 12. The tank 12 is connected to one end of the flow path R1. The other end of the flow path R1 branches into flow paths R2A to R2C.

[0055] The flow path R2A is connected to the discharge mechanism 125A. The discharge mechanism 125A has, for example, a coolant nozzle (not shown) connected to the flow path R2A and discharges the coolant pumped to the flow path R2A from the coolant nozzle toward the spindle. The spindle may be a tool spindle that rotates a tool or a workpiece spindle that rotates a workpiece. When the coolant is discharged onto the spindle, the chips of the workpiece adhering to the spindle are discharged to the chip conveyor 150.

[0056] The flow path R2B is connected to the discharge mechanism 125B. The discharge mechanism 125B is provided on the ceiling of the machining area AR. The discharge mechanism 125B discharges the coolant pumped to the flow path R2B toward the entire machining area AR. As a result, the chips of the workpiece in the machining area AR are discharged to the chip conveyor 150.

[0057] The flow path R2C is connected to the discharge mechanism 125C. The discharge mechanism 125C discharges the coolant pumped to the flow path R2C toward the wall surface of the bed BD. As a result, the chips accumulated on the bed BD are discharged to the chip conveyor 150.

[0058] When the pump 160 is driven, it pumps the coolant stored in the above-described tank 12 into the flow path R1. Thereby, the pump 160 sends the coolant from the tank 12 to the discharge part 125.

[0059] Valves may be provided in each of the flow paths R2A to R2C. The valve is a control valve that controls the flow rate of the coolant pumped from the tank 12 toward the discharge mechanisms 125A to 125C. Note that the valve does not necessarily have to be provided on the flow paths R2A to R2C and may be integrally configured with the pump 160.

[0060] As described above, the chip conveyor 150 has the tank 11 and the filter mechanism 39. The filter mechanism 39 is configured to be able to capture foreign matters such as chips contained in the coolant. The coolant that has passed through the filter mechanism 39 is discharged from inside the cover body 21 of the chip conveyor 150 to the tank 11. Thereby, the tank 11 receives the coolant discharged to the processing area AR.

[0061] A water level sensor 151 is provided inside the tank 11. Preferably, the water level sensor 151 is arranged on the downstream side of the filter mechanism 39 in the direction of the flow of the coolant passing through the filter mechanism 39. As the water level sensor 151, any type of sensor can be adopted as long as it can detect a physical quantity correlated with the water level of the liquid coolant in the tank 11. As an example, the water level sensor 151 may be a float switch, a weight sensor, or other sensors.

[0062] Further, the tank 11 is provided with a pump 152 for pumping up the coolant. Preferably, the pump 152 is configured to pump up the coolant on the downstream side of the filter mechanism 39 in the flow direction of the coolant passing through the filter mechanism 39. The pump 152 pumps up the coolant that has passed through the filter mechanism 39 and sends the coolant to the tank 12 through the flow path R3. The coolant in the tank 12 is pumped again through the flow path R1 by the pump 160.

[0063] Inside the tank 12, a water level sensor 155 is provided. The water level sensor 155 is a sensor for detecting the height of the upper surface of the foamed coolant in the tank 12. As the water level sensor 155, any type of sensor can be adopted as long as it can detect a physical quantity correlated with the height of the upper surface of the foamed coolant in the tank 12. As an example, the water level sensor 155 may be a distance sensor or other sensors.

[0064] <E. Control Mode of Pump 152> Next, with reference to FIG. 6, the control mode of the above-described pump 152 will be described. FIG. 6 is a diagram for explaining an ON / OFF control mode which is an example of the control mode of the pump 152.

[0065] In the ON / OFF control mode, the control device 50 controls the pump 152 so that the water level CH in the tank 11 increases and decreases between the threshold values th1 and th2.

[0066] More specifically, first, the control device 50 turns off the pump 152. As a result, the discharge of the coolant from the tank 11 to the tank 12 stops. On the other hand, during machining, the control device 50 continues to drive the pump 160 described above. As a result, the coolant in the tank 12 is discharged into the machining area AR in the machine tool 100, and the coolant used for machining the workpiece is stored in the tank 11. As a result, the amount of coolant in the tank 11 increases, and the amount of coolant in the tank 12 decreases. At this time, the control device 50 periodically obtains the water level CH in the tank 11 from the water level sensor 151 described above, and determines whether or not the water level CH exceeds the threshold value th1. The threshold value th1 is set at a position higher than the position of the suction port SP of the pump 152. The threshold value th1 may be set in advance or may be arbitrarily set by the user.

[0067] When the control device 50 determines that the water level CH has exceeded the threshold value th1, it drives the pump 152. At this time, the control device 50 controls the pump 152 so that the discharge amount of the coolant from the tank 11 to the tank 12 is larger than the discharge amount of the coolant from the tank 12 to the machining area AR. As an example, the control device 50 drives the pump 152 at the maximum rotational speed (for example, 50 Hz to 60 Hz) that can be set. As a result, the amount of coolant in the tank 11 decreases, and the amount of coolant in the tank 12 increases.

[0068] Next, the control device 50 determines whether or not the water level CH in the tank 11 has fallen below the threshold value th2 based on the output value of the water level sensor 151 described above. The threshold value th2 is set at a position lower than the position of the suction port SP of the pump 152. The threshold value th2 may be set in advance or may be arbitrarily set by the user. When the control device 50 determines that the amount of coolant in the tank 11 has fallen below the threshold value th2, it stops driving the pump 152.

[0069] As described above, in the ON / OFF control mode, the control device 50 controls the pump 152 so that the water level CH in the tank 11 increases and decreases between the threshold values th1 and th2. As a result, the height of the liquid level in the tank 11 fluctuates, and the oil floating on the liquid level in the tank 11 and the bubbly coolant CLB are discharged from the suction port SP of the pump 152 to the tank 12.

[0070] <F. Float pump 170> Next, with reference to FIG. 7, the float pump 170 provided in the tank 12 will be described. FIG. 7 is a diagram for explaining the float pump 170.

[0071] As shown in FIG. 7, a float pump 170 is provided inside the tank 12. The float pump 170 is a float-type pump configured to float on the liquid coolant CLL stored inside the tank 12. Since the float pump 170 floats on the liquid level of the liquid coolant CLL, it can suck the oil floating on the liquid coolant CLL and the bubbly coolant CLB.

[0072] The sucked oil and bubbly coolant CLB are discharged to the outside of the machine tool 100 through a discharge pipe (not shown) connected to the float pump 170. Preferably, the sucked oil and bubbly coolant CLB are discharged to a foreign matter separation device. The coolant from which foreign matters have been separated is reused for workpiece processing.

[0073] <G. Drive mechanism> Next, with reference to FIG. 8, various drive mechanisms in the machine tool 100 will be described. FIG. 8 is a diagram showing a configuration example of the drive mechanism in the machine tool 100.

[0074] As shown in FIG. 8, the machine tool 100 includes, as a configuration related to the drive mechanism, a control device 50, motor drivers 111A to 111D, motors MA to MD, the above-described pumps 152 and 160, the above-described float pump 170, and the above-described chip conveyor 150.

[0075] As described above, the pump 152 is a device for pumping the coolant through the flow path R3 (see FIG. 5). A motor MA is connected to the pump 152. The motor MA may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0076] The motor MA is driven by a motor driver 111A. The motor driver 111A is composed of a control circuit, an inverter, and the like. The motor driver 111A receives an input of a control signal from the control device 50 and outputs an alternating current with a frequency corresponding to the control signal to the motor MA. Thereby, the rotational speed of the motor MA changes, and the flow rate of the coolant pumped through the above-described flow path R3 is controlled.

[0077] As described above, the pump 160 is a device for pumping the coolant through the flow path R1 (see FIG. 5). A motor MB is connected to the pump 160. The motor MB may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0078] The motor MB is driven by a motor driver 111B. The motor driver 111B is composed of a control circuit, an inverter, and the like. The motor driver 111B receives an input of a control signal from the control device 50 and outputs an alternating current with a frequency corresponding to the control signal to the motor MB. Thereby, the rotational speed of the motor MB changes, and the flow rate of the coolant pumped through the above-described flow path R1 is controlled.

[0079] As described above, the float pump 170 is a float-type pump configured to float on the liquid coolant CLL stored inside the tank 12. A motor MC is connected to the float pump 170. The motor MC may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0080] The motor MC is driven by the motor driver 111C. The motor driver 111C is composed of a control circuit, an inverter, and the like. The motor driver 111C receives an input of a control signal from the control device 50 and outputs an alternating current with a frequency corresponding to the control signal to the motor MC. Thereby, the rotational speed of the motor MC changes, and the flow rate of the coolant sucked up from the tank 12 is controlled.

[0081] A motor MD is connected to the above-described chip conveyor 150 (see FIG. 4). The motor MD may be an AC motor, a stepping motor, a servo motor, or other types of motors.

[0082] The motor MD is driven by the motor driver 111D. The motor driver 111D is composed of a control circuit, an inverter, and the like. The motor driver 111D receives an input of a control signal from the control device 50 and outputs an alternating current with a frequency corresponding to the control signal to the motor MD. Thereby, the rotational speed of the motor MD changes, and the rotational speed of the conveyor in the chip conveyor 150 is controlled.

[0083] <H. Control device 50> Next, with reference to FIG. 9, the above-described control device 50 will be described. FIG. 9 is a diagram showing an example of the hardware configuration of the control device 50.

[0084] The control device 50 is a device for controlling the machine tool 100. The device configuration of the control device 50 is arbitrary. The control device 50 may be composed of a single control unit or a plurality of control units. As an example, the control device 50 includes at least one of a PLC (Programmable Logic Controller) and a CNC (Computer Numerical Control).

[0085] The control device 50 includes a control circuit 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, communication interfaces 204 and 205, and an auxiliary storage device 220. These components are connected to an internal bus 209.

[0086] The control circuit 201 is constituted by, for example, at least one integrated circuit. The integrated circuit can be constituted by, for example, at least one CPU, at least one GPU (Graphics Processing Unit), at least one ASIC (Application Specific Integrated Circuit), at least one FPGA (Field Programmable Gate Array), or a combination thereof.

[0087] The control circuit 201 controls the operation of the CPU unit 20 by executing various programs such as a control program 222. The control program 222 defines instructions for controlling various devices within the machine tool 100. Based on receiving an execution instruction of the control program 222, the control circuit 201 reads the control program 222 from the auxiliary storage device 220 or the ROM 202 into the RAM 203. The RAM 203 functions as a working memory and temporarily stores various data necessary for the execution of the control program 222.

[0088] The communication interface 204 is an interface for realizing communication using a LAN (Local Area Network) cable, WLAN (Wireless LAN), or Bluetooth (registered trademark), etc.

[0089] The communication interface 205 is an interface for performing periodic communication with external devices using a field network. As the field network, for example, EtherCAT (registered trademark), EtherNet / IP (registered trademark), CC-Link (registered trademark), or CompoNet (registered trademark) is adopted. The control device 50 realizes communication with the above-described pump 152, the above-described pump 160, and the above-described float pump 170, etc., via the communication interface 305, for example.

[0090] The auxiliary storage device 220 is a storage medium such as a hard disk or a flash memory, for example. The auxiliary storage device 220 stores various information such as a control program 222 and setting parameters 224. The setting parameters 224 define various parameters that are referred to during the execution of the control program 222. As an example, the setting parameters 224 define the above-described threshold values th1, th2 (see FIG. 6) and the threshold value th3 (see FIG. 11) described later, etc.

[0091] The storage locations of the control program 222 and the setting parameters 224 are not limited to the auxiliary storage device 220, and may be stored in the storage area of the control circuit 201 (for example, cache memory), ROM 202, RAM 203, an external device (for example, a server), etc.

[0092] Note that the control program 222 may be provided not as a single program but incorporated as part of an arbitrary program. In this case, various processes according to the present embodiment are realized in cooperation with an arbitrary program. Even a program that does not include such a part of the module does not deviate from the gist of the control program 222 according to the present embodiment. Further, part or all of the functions provided by the control program 222 may be realized by dedicated hardware. Further, the CPU unit 20 may be configured in a form such as a so-called cloud service in which at least one server executes part of the processing of the control program 222.

[0093] <I. Flowchart related to pump control processing> Next, with reference to FIG. 10, the ON / OFF control flow described in FIG. 6 above will be described. FIG. 10 is a flowchart showing the flow of ON / OFF control.

[0094] The process shown in FIG. 10 is performed by the control device 50 executing the above-described control program 222. Note that part or all of the process shown in FIG. 10 may be executed by a circuit element or other hardware.

[0095] In step S110, the control device 50 turns off the above-described pump 152. As a result, the discharge of the coolant from the tank 11 to the tank 12 stops. On the other hand, the control device 50 continues to drive the above-described pump 160 during processing. As a result, the amount of coolant in the tank 11 increases, and the amount of coolant in the tank 12 decreases.

[0096] In step S120, the control device 50 determines whether or not the water level CH in the tank 11 exceeds the threshold value th1 based on the output value of the above-described water level sensor 151. As described above, the threshold value th1 is set at a position higher than the position of the suction port SP of the pump 152. When the control device 50 determines that the water level CH in the tank 11 exceeds the threshold value th1 (YES in step S120), the control is switched to step S122. Otherwise (NO in step S120), the control device 50 repeats the process of step S120.

[0097] In step S122, the control device 50 turns on the above-described pump 152. As a result, the coolant in the tank 11 is discharged to the tank 12. On the other hand, the control device 50 continues to drive the above-described pump 160 during processing. At this time, the control device 50 controls the pump 152 so that the discharge amount of the coolant from the tank 11 to the tank 12 is larger than the discharge amount of the coolant from the tank 12 to the processing area AR. As a result, the amount of coolant in the tank 11 decreases, and the amount of coolant in the tank 12 increases.

[0098] In step S130, the control device 50 determines whether or not the water level CH in the tank 11 has fallen below the threshold value th2 based on the output value of the water level sensor 151 described above. As described above, the threshold value th2 is set at a position lower than the position of the suction port SP of the pump 152. When the control device 50 determines that the water level CH in the tank 11 has fallen below the threshold value th2 (YES in step S130), the control returns to step S110. Otherwise (NO in step S130), the control device 50 executes the process of step S130 again.

[0099] <J. Flowchart related to abnormal monitoring process> As described above, the machine tool 100 aggregates the foamy coolant CLB from the tank 11 to the tank 12. At this time, the machine tool 100 monitors the amount of the foamy coolant CLB in the tank 12, and when the amount of the foamy coolant CLB reaches a threshold value, executes a predetermined abnormality countermeasure process.

[0100] Hereinafter, with reference to FIG. 11, the control flow related to the abnormal monitoring process will be described. FIG. 11 is a flowchart showing the flow of the abnormal monitoring process.

[0101] The process shown in FIG. 11 is performed by the control device 50 executing the control program 222 described above. Note that part or all of the process shown in FIG. 11 may be executed by a circuit element or other hardware.

[0102] In step S150, the control device 50 determines whether or not the height of the upper surface of the foamy coolant in the tank 12 has reached a predetermined threshold value th3 based on the output value of the water level sensor 155 described above. When the control device 50 determines that the height of the upper surface of the foamy coolant in the tank 12 has reached a predetermined threshold value th3 (YES in step S150), the control switches to step S152. Otherwise (NO in step S150), the control device 50 executes the process of step S150 again.

[0103] In step S152, the control device 50 executes predetermined abnormality handling processes. As an example, the abnormality handling processes include a notification process for notifying an operator that the amount of the foamed coolant in the tank 12 has exceeded the allowable amount. The notification process is realized, for example, by displaying a message indicating the occurrence of an abnormality on the display 306 described above. Alternatively, the notification process is realized by lighting an abnormality lamp (not shown) provided in the machine tool 100.

[0104] As another example of the abnormality handling processes, the control device 50 includes a process of starting the drive of the float pump 170 (see FIG. 7) described above. Thereby, the foamed coolant accumulated in the tank 12 is discharged to the outside of the tank 12. Note that the float pump 170 may be driven only during the abnormality handling processes, or may be driven constantly.

[0105] As another example of the abnormality handling processes, the control device 50 includes a process of stopping the machine tool 100. Thereby, the machine tool 100 can prevent the foamed coolant from overflowing from the tank 12.

[0106] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0107] 11 tank, 12 tank, 13 chip conveyor, 20 CPU unit, 21 cover body, 22 horizontal part, 23 chip receiving part, 24 connection port, 26 rising part, 27 discharge port, 28 coolant discharge part, 34 endless chain, 35 chip conveying part, 37 drive sprocket, 38 driven sprocket, 39 filter mechanism, 46 drum filter, 47 internal space, 50 control device, 100 machine tool, 111A motor driver, 111B motor driver, 111C motor driver, 111D motor driver, 125 discharge part, 125A discharge mechanism, 125B discharge mechanism, 125C discharge mechanism, 130 cover body, 150 chip conveyor, 151 water level sensor, 152 pump, 155 water level sensor, 160 pump, 170 float pump, 201 control circuit, 202 ROM, 203 RAM, 204 communication interface, 205 communication interface, 209 internal bus, 220 auxiliary storage device, 222 control program, 224 setting parameter, 300 operation panel, 305 communication interface, 306 display, AR machining area, AX1 axis, BD bed, CH water level, CLB foamy coolant, CLL liquid coolant, LS liquid level, MA motor, MB motor, MC motor, MD motor, R1 flow path, R2A flow path, R2B flow path, R2C flow path, R3 flow path, SP suction port, th1 threshold value, th2 threshold value, th3 threshold value.

Claims

1. A machine tool capable of machining a workpiece, a first tank for storing coolant used for machining the workpiece, a pump for pumping up the coolant stored in the first tank, a second tank for storing the coolant pumped up by the pump, and a control device for controlling the pump so as to send the bubbles and the coolant generated inside the first tank to the second tank. A machine tool.

2. The machine tool according to claim 1, further comprising a filter mechanism provided inside the first tank for removing foreign matters contained in the coolant.

3. The machine tool according to claim 2, wherein the filter mechanism is a drum filter configured to remove the foreign matters from the coolant flowing from the outside to the inside.

4. The machine tool according to any one of claims 1 to 3, wherein the control process includes controlling the pump so that the liquid level of the liquid coolant stored inside the first tank passes through the suction port of the pump.

5. The machine tool includes a sensor for detecting the height of the upper surface of the foamy coolant stored in the second tank, and the control device executes a predetermined abnormality countermeasure process based on the fact that the height of the upper surface of the foamy coolant has reached a predetermined threshold value. The machine tool according to any one of claims 1 to 3.

6. The machine tool according to any one of claims 1 to 3, further comprising a float type pump configured to float on the liquid coolant stored inside the second tank.

7. A tank capable of storing coolant used for machining a workpiece by a machine tool, The machine tool includes a pump for pumping up the coolant stored in the tank, and another tank for storing the coolant pumped up by the pump, and the tank is configured such that when the pump is controlled, the bubbles and the coolant generated inside the tank are sent to the other tank.

8. A tank used in a machine tool, the machine tool includes another tank for storing the coolant used for machining the workpiece, and a pump for sending the coolant stored in the other tank to the tank, and the tank is configured such that when the pump is controlled, the bubbles and the coolant generated inside the other tank are sent.

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