Machine tool
Patent Information
- Application Number
- PCT/JP2026/006582
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-12
- Filing Date
- 2026-02-24
- Publication Date
- 2026-09-17
Smart Images
Figure JP2026006582_17092026_PF_FP_ABST
Abstract
Description
MACHINE TOOL
[0001] The present invention relates to a machine tool capable of identifying the type of a coolant.
[0002] Water-soluble coolants and oil-based coolants are known as coolants used in machine tools. Generally, the water-soluble coolants are often used in machine tools, but the oil-based coolants may be used, for example, when high-load machining is performed. Since the oil-based coolant and the water-soluble coolant have different characteristics, it is necessary to prevent the oil-based coolant from being supplied to a machine tool designed for use in the water-soluble coolant.
[0003] Regarding such a problem, PTL 1 discloses a device that prevents mixing of different types of coolants in a machine tool. This device uses a sensor as quality detection means for detecting whether the coolant flowing into a waste tank, in which the used coolant is stored, is water-soluble or oil-based.
[0004] [PTL 1] Japanese Patent Laying-Open No. H07-60600
[0005] PTL 1 discloses that the type of a coolant is identified by the quality sensing means but does not disclose a specific method by which the quality sensing means identifies the type of a coolant.
[0006] The present invention aims to identify the type of a coolant used in a machine tool.
[0007] A machine tool according to an aspect of the present invention is a machine tool capable of machining while supplying a coolant. The machine tool includes: a machining unit that performs machining; a tank including (i) a first tank portion in which the coolant that has flowed from the machining unit flows toward a drum filter, and (ii) a second tank portion located beyond a position at which the coolant that has flowed to the drum filter and flowed while changing a flow direction toward an end of the drum filter flows through the end; and a sensor that senses the coolant in the tank for identifying whether the coolant is a water-soluble coolant or an oil-based coolant.
[0008] A machine tool according to another aspect of the present invention includes a sensor unit that transmits a signal wave toward a coolant and receives a reflection thereof, and an identification device that identifies a type of the coolant based on a signal received by the sensor unit. The machine tool is configured to obtain different measurement results based on the signal from the sensor unit between a case where a water-soluble coolant is stored in a coolant tank and a case where an oil-based coolant is stored in the coolant tank. The machine tool identifies a type of the coolant based on the measurement result.
[0009] A machine tool according to still another aspect of the present invention is a machine tool that identifies a type of a coolant stored in a coolant tank. The machine tool includes a sensor unit that emits a first transmission wave and a second transmission wave toward a bottom surface of the coolant tank and receives a reflected wave of the first transmission wave and a reflected wave of the second transmission wave, and an identification device that identifies a type of a coolant from a measurement result obtained based on a signal intensity of the reflected wave of the first transmission wave and a signal intensity of the reflected wave of the second transmission wave received by the sensor unit. The identification device obtains a measurement result based on a signal intensity of a first liquid level reflected wave, which is a reflected wave generated by the first transmission wave being reflected off a liquid level of a water-soluble coolant and a signal intensity of a second liquid level reflected wave, which is a reflected wave generated by the second transmission wave being reflected off the liquid level of the water-soluble coolant when the water-soluble coolant is stored in the coolant tank, and obtains a measurement result based on a signal intensity of a first liquid level reflected wave, which is a reflected wave generated by the first transmission wave being reflected off a liquid level of an oil-based coolant and a signal intensity of a second bottom surface reflected wave, which is a reflected wave generated by the second transmission wave being reflected off the bottom surface of the oil-based coolant, such that a measurement result when the water-soluble coolant is stored in the coolant tank is different from a measurement result when the oil-based coolant, which has a lower relative dielectric constant than that of the water-soluble coolant, is stored in the coolant tank,. When the oil-based coolant is stored in the coolant tank, the identification device.
[0010] A machine tool according to still another aspect of the present invention is a machine tool capable of machining while supplying a coolant. The machine tool includes a machining unit that performs machining, a tank that contains the coolant for supplying the coolant to the machining unit, and a sensor that senses the coolant with the coolant in the tank, for identifying whether the coolant is a water-soluble coolant or an oil-based coolant.
[0011] The machine tool according to the present invention can identify the type of a coolant used in a machine tool.
[0012] Fig. 1 is a schematic diagram showing a machine tool of Embodiment 1.Fig. 2 is a diagram schematically showing measurement by a sensor unit when a coolant is a water-soluble coolant in Embodiment 1.Fig. 3 is a diagram schematically showing measurement by the sensor unit when the coolant is an oil-based coolant in Embodiment 1.Fig. 4 is a diagram showing measurement results for the water-soluble coolant and the oil-based coolant in Embodiment 1.Fig. 5 is a flowchart of determination leading to the execution of first abnormality processing in the machine tool.Fig. 6 is a flowchart of determination leading to the execution of second abnormality processing in the machine tool.Fig. 7 is a flowchart of determination leading to the execution of third abnormality processing in the machine tool.Fig. 8 is a diagram schematically showing measurement by a sensor unit when the coolant is a water-soluble coolant in a machine tool of Embodiment 2.Fig. 9 is a diagram schematically showing measurement by the sensor unit when the coolant is an oil-based coolant in the machine tool of Embodiment 2.Fig. 10 is a diagram showing measurement results for the water-soluble coolant and the oil-based coolant in the machine tool of Embodiment 2.Fig. 11 is a top view schematically showing the machine tool.Fig. 12 is a block diagram schematically showing a coolant flow in a machine tool in Embodiment 3.Fig. 13 is a top view showing a tank and a chip conveyor in the machine tool of Fig. 12.Fig. 14 is a perspective view partially showing the tank and the chip conveyor in the machine tool of Fig. 12.Fig. 15 is a block diagram schematically showing a coolant flow in a machine tool in Embodiment 4.Fig. 16 is a top view showing a tank and a chip conveyor in the machine tool of Fig. 15.Fig. 17 is a sectional view showing a secondary tank in the machine tool of Fig. 15.
[0013] Embodiments of the present invention will be described below with reference to the drawings.
[0014] <Embodiment 1> Fig. 1 is a schematic diagram showing a machine tool of Embodiment 1. A machine tool 100 includes a machine tool body 1 and a coolant tank 2. A coolant C is stored in coolant tank 2 and supplied to machine tool body 1. Coolant C used in machine tool body 1 returns to coolant tank 2. Machine tool 100 further includes a sensor unit 3 and an identification device 4. Sensor unit 3 emits a first transmission wave and a second transmission wave toward coolant C in coolant tank 2 and receives reflected waves thereof. Identification device 4 obtains measurement results based on the signal intensities of the received reflected waves. The first transmission wave and the second transmission wave are set such that the measurement results differ between the case where the coolant stored in coolant tank 2 is a water-soluble coolant and the case where the coolant is an oil-based coolant. Identification device 4 identifies the type of coolant C stored in coolant tank 2 based on the obtained measurement results. Identification device 4 identifies the type of the coolant when machine tool body 1 is powered on. Each component will be described below in detail.
[0015] Machine tool body 1 is not particularly limited and may be, for example, a multi-tasking machine, for example, a numerically controlled (NC) machine tool. Further, machine tool body 1 is a machine tool designed for a water-soluble coolant. Machine tool body 1 is configured to spray the coolant, supplied from coolant tank 2, into a machining chamber.
[0016] Fig. 11 is a top view schematically showing the machine tool. In Fig. 11, components constituting machine tool body 1 are appropriately omitted such that the interior of a machining chamber 11 are visible. Coolant tank 2 is provided near machine tool body 1. Coolant tank 2 has an L shape in top view. Coolant tank 2 includes a primary tank 22, in which the coolant used in machine tool body 1 is stored, and a secondary tank 23, in which the coolant in the primary tank has been purified by a filter or the like is stored. Part of primary tank 22 is provided at the lower portion of machine tool body 1. Part of primary tank 22 is provided below machining chamber 11. Primary tank 22 recovers the coolant used in the machining chamber. A chip conveyor 25, which conveys chips, is provided in primary tank 22. The chips conveyed by chip conveyor 25 are discharged through a discharge port 26 of chip conveyor 25. Secondary tank 23 is connected to primary tank 22 and is configured to allow the coolant stored in primary tank 22 to flow thereinto. The coolant from which chips have been removed by chip conveyor 25 flows into secondary tank 23. Secondary tank 23 is provided beside machine tool body 1. The coolant in secondary tank 23 is supplied to machine tool body 1 by a pump 24 or the like. The bottom surface of coolant tank 2 is formed of a metal plate. The metal plate is made of, for example, steel.
[0017] Sensor unit 3 includes a first sensor 31 and a second sensor 32. First sensor 31 and second sensor 32 are radar sensors. First sensor 31 and second sensor 32 are configured to emit high-frequency radar and receive the reflected wave thereof. First sensor 31 and second sensor 32 are arranged in close proximity. First sensor 31 and second sensor 32 are disposed above the liquid level of coolant C stored in coolant tank 2. First sensor 31 and second sensor 32 do not come into contact with coolant C. In the present embodiment, first sensor 31 and second sensor 32 are positioned above the coolant stored in secondary tank 23. However, first sensor 31 and second sensor 32 may be positioned above the coolant stored in primary tank 22. In short, first sensor 31 and second sensor 32 are only required to be positioned so as to apply radar toward the coolant supplied to machine tool body 1. First sensor 31 and second sensor 32 are provided in secondary tank 23 near the portion of connection with primary tank 22. First sensor 31 and second sensor 32 are provided near pump 24. First sensor 31 and second sensor 32 are, for example, attached to the outer peripheral edge of coolant tank 2 (secondary tank 23) and emit radar toward the coolant near the outer peripheral edge. However, first sensor 31 and second sensor 32 are not limited to being attached to the outer peripheral edge and may be supported via a support member and disposed above the center of coolant tank 2. A line 40 is the extension line of the upper wall surface of machining chamber 11 in the paper, and a line 41 is the extension line of the lower wall surface of machining chamber 11 in the paper. Herein, first sensor 31 and second sensor 32 are disposed within the range bounded by line 40 and line 41.
[0018] Referring to Fig. 1, first sensor 31 and second sensor 32 are disposed to emit radar toward the bottom surface of coolant tank 2. First sensor 31 and second sensor 32 are disposed such that the emitted radar extends along the vertical direction. First sensor 31 and second sensor 32 are disposed adjacent to each other. First sensor 31 and second sensor 32 are disposed in close proximity. First sensor 31 and second sensor 32 emit radar toward substantially the same location of coolant tank 2. First sensor 31 and second sensor 32 are each connected to machine tool body 1 in a wired or wireless manner. The signal intensity emitted by each of first sensor 31 and second sensor 32 is set in machine tool body 1.
[0019] Fig. 2 is a diagram schematically showing measurement by the sensor unit when the coolant is a water-soluble coolant in Embodiment 1. Part (A) of the figure shows measurement by first sensor 31, and part (B) of the figure shows measurement by second sensor 32. Referring to (A), first sensor 31 functions as a water level sensor that measures the water level of the coolant stored in coolant tank 2. First sensor 31 emits a first transmission wave 311 toward a bottom surface 21 of coolant tank 2. First transmission wave 311 is, for example, a high-frequency millimeter-wave radar of approximately 60 GHz. First transmission wave 311 is reflected off the liquid level of a water-soluble coolant C1. A first liquid level reflected wave 312, which is a reflected wave of first transmission wave 311, travels toward first sensor 31, and first sensor 31 receives first liquid level reflected wave 312. First sensor 31 transmits, to identification device 4, information on the signal intensity of the received first liquid level reflected wave 312.
[0020] Herein, the relative dielectric constant of water-soluble coolant C1 is approximately 70. Consequently, the reflection coefficient on the liquid level is high, and first transmission wave 311 is reflected as first liquid level reflected wave 312 of a strong signal intensity. In other words, first liquid level reflected wave 312 maintains a signal intensity close to that of first transmission wave 311. Part of first transmission wave 311 is not reflected off the liquid level but passes through water-soluble coolant C1. The part of first transmission wave 311 that has passed through water-soluble coolant C1 is reflected off bottom surface 21 of coolant tank 2, and first sensor 31 receives a reflected wave thereof. However, the machine tool of the present embodiment is configured to ignore the reflected wave (hereinafter referred to as a first bottom surface reflected wave) of first transmission wave 311 reflected off bottom surface 21. Specifically, the identification device, which will be described later, identifies whether the received reflected wave is first liquid level reflected wave 312 based on the reception time for first liquid level reflected wave 312 that is a reflected wave reflected off the liquid level (the distance from the first sensor to the reflection position) and the reception time for the first bottom surface reflected wave that has passed through water-soluble coolant C1 and has been reflected off the bottom surface (the distance from the first sensor to the reflection position), and then, excludes the first bottom surface reflected wave, which has been reflected off the bottom surface, from computation processing.
[0021] Referring to (B), second sensor 32 emits a second transmission wave 321 toward bottom surface 21 of coolant tank 2. Second transmission wave 321 is, similarly to first transmission wave 311, a high-frequency millimeter-wave radar of, for example, approximately 60 GHz. However, the signal intensity of second transmission wave 321 is weaker than that of first transmission wave 311. The signal intensity of second transmission wave 321 is set to be weaker than that of first transmission wave 311 by, for example, adjusting the gain of second sensor 32. Second transmission wave 321 is reflected off the liquid level of water-soluble coolant C1. A second liquid level reflected wave 322, which is a reflected wave of second transmission wave 321, travels toward second sensor 32, and second sensor 32 receives second liquid level reflected wave 322. Second transmission wave 321 is, similarly to first transmission wave 311, reflected as second liquid level reflected wave 322 of a strong signal intensity. In other words, second liquid level reflected wave 322 maintains a signal intensity close to that of second transmission wave 321. Second sensor 32 transmits, to identification device 4, information on the signal intensity of the received second liquid level reflected wave 322. Similarly to first transmission wave 311, the reflected wave (hereinafter referred to as a second bottom surface reflected wave) generated by second transmission wave 321 being reflected off the bottom surface is excluded from computation processing.
[0022] Identification device 4 obtains measurement results for the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322. Specifically, identification device 4 has a preset threshold for the signal intensity. Identification device 4 compares the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 with the threshold. Identification device 4 determines whether the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 are each greater than or equal to the threshold or less than the threshold.
[0023] Herein, when the coolant is water-soluble coolant C1, both the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 are equal to or greater than the threshold. In other words, in both first sensor 31 and second sensor 32, the signal intensity of first transmission wave 311 and the signal intensity of second transmission wave 321 are set in advance such that the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 exceed the threshold. Next, the case of an oil-based coolant will be described.
[0024] Fig. 3 is a diagram schematically showing measurement by the sensor unit when the coolant is an oil-based coolant in Embodiment 1. Part (A) of the figure shows measurement by first sensor 31, and Part (B) of the figure shows measurement by second sensor 32. Referring to (A), first sensor 31, as in the case of the water-soluble coolant described above, emits first transmission wave 311 toward bottom surface 21 of coolant tank 2 and receives first liquid level reflected wave 312. First transmission wave 311 when the coolant is an oil-based coolant is a signal of the same signal intensity as that of the first transmission wave in the case of the water-soluble coolant. Referring to Part (B), second sensor 32 emits second transmission wave 321 toward bottom surface 21 of coolant tank 2, as in the case of the water-soluble coolant described above, and receives second liquid level reflected wave 322. Second transmission wave 321 when the coolant is an oil-based coolant is a signal of the same signal intensity as that of the second transmission wave in the case of the water-soluble coolant. Thus, even when the coolant is an oil-based coolant, the signal intensity of second transmission wave 321 is set to be weaker than that of first transmission wave 311.
[0025] Herein, the relative dielectric constant of an oil-based coolant C2 is approximately 2, which is lower than that of water-soluble coolant C1. Consequently, the reflection coefficient on the liquid level is lower than that of water-soluble coolant C1, and accordingly, compared to the case of water-soluble coolant C1, first transmission wave 311 and second transmission wave 321 are reflected as first liquid level reflected wave 312 and second liquid level reflected wave 322 of weaker signal intensities, respectively. In other words, when the coolant is an oil-based coolant, each of first liquid level reflected wave 312 and second liquid level reflected wave 322 has a signal intensity attenuated more than that of the water-soluble coolant.
[0026] Identification device 4 obtains measurement results for the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322, respectively, as in the case of the water-soluble coolant. In other words, identification device 4 determines whether the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 are each greater than or equal to the threshold or less than the threshold.
[0027] When the coolant is oil-based coolant C2, first liquid level reflected wave 312 is greater than or equal to the threshold, and second liquid level reflected wave 322 is less than the threshold. In other words, in first sensor 31 and second sensor 32, the signal intensity of first transmission wave 311 and the signal intensity of second transmission wave 321 are set in advance such that the signal intensity of first liquid level reflected wave 312 is greater than or equal to the threshold and the signal intensity of second liquid level reflected wave 322 is less than the threshold.
[0028] Fig. 4 is a diagram showing measurement results for a water-soluble coolant and an oil-based coolant in Embodiment 1. As described above, when the coolant is a water-soluble coolant, both the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 received by sensor unit 3 are greater than or equal to the threshold. Identification device 4 determines the measurement result as "OK" when the signal intensity of the reflected wave is greater than or equal to the threshold. Thus, when the coolant is a water-soluble coolant, the measurement results are "OK-OK" as shown in the figure.
[0029] In contrast, when the coolant is an oil-based coolant, the signal intensity of first liquid level reflected wave 312 received by sensor unit 3 is greater than or equal to the threshold, but the signal intensity of second liquid level reflected wave 322 is less than the threshold. Identification device 4 determines the measurement result as "NG" when the signal intensity of the reflected wave is less than the threshold. Thus, when the coolant is an oil-based coolant, the measurement results are "OK-NG" as shown in the figure, which are different from the measurement results for the water-soluble coolant.
[0030] When the measurement results are "OK-OK", identification device 4 determines that the coolant stored in coolant tank 2 is a water-soluble coolant. When the measurement results are "OK-NG", identification device 4 determines that the coolant stored in coolant tank 2 is an oil-based coolant.
[0031] Thus, in machine tool 100, sensor unit 3 emits two different transmission waves of different signal intensities toward the coolant stored in the coolant tank. The signal intensities of first transmission wave 311 and second transmission wave 321 are set such that the measurement results based on the respective reflected waves thereof, that is, the first liquid level reflected wave and the second liquid level reflected wave, differ between the water-soluble coolant and the oil-based coolant. Thus, machine tool 100 can identify the type of the coolant used in machine tool body 1.
[0032] In machine tool 100, first sensor 31 also functions as a water level sensor. Thus, machine tool 100 can not only identify the type of a coolant but also measure the water level of the coolant.
[0033] <Modifications> When machine tool 100 identifies the coolant stored in coolant tank 2 as a water-soluble coolant, machine tool 100 may instruct machine tool body 1 to machine a workpiece according to a predetermined machining program. In contrast, when machine tool 100 identifies the coolant stored in coolant tank 2 as an oil-based coolant, machine tool 100 may instruct machine tool body 1 to perform at least one of the following various pieces of abnormality processing. The various pieces of abnormality processing will be described below.
[0034] Fig. 5 is a flowchart of the determination leading to the execution of first abnormality processing in the machine tool. First, identification device 4 in machine tool 100 identifies the type of the coolant stored in coolant tank 2 (step S11).
[0035] When determining that the coolant stored in coolant tank 2 is a water-soluble coolant (YES in step S11), identification device 4 permits machine tool body 1 to machine a workpiece (step S15). When determining that the coolant stored in coolant tank 2 is an oil-based coolant (NO in step S11), identification device 4 determines whether machine tool body 1 is a machine tool designed for a water-soluble coolant or a machine tool designed for an oil-based coolant (step S12).
[0036] The machine tool designed for an oil-based coolant is equipped with fire prevention equipment. The fire prevention equipment is, for example, an automatic fire extinguisher. In contrast, the machine tool designed for a water-soluble coolant is generally not equipped with fire prevention equipment but may be equipped with individually designed fire prevention equipment. Information regarding the specifications of the machine tool are stored in, for example, a memory installed on the machine tool. Identification device 4 communicates with machine tool body 1 in a wireless or wired manner. Identification device 4 acquires information regarding the specifications of machine tool body by communicating with the machine tool. Steps S11 and S12 may be performed in a reverse order or performed simultaneously. Furthermore, identification device 4 may possess information in advance regarding the specifications of machine tool body 1. In this case, step S12 is omitted.
[0037] When determining that machine tool body 1 is a machine tool designed for an oil-based coolant (YES in step S12), identification device 4 permits machine tool body 1 to machine the workpiece (step S15). When determining that machine tool body 1 is a machine tool designed for a water-soluble coolant (NO in step S12), identification device 4 determines whether machine tool body 1 is equipped with an automatic fire extinguisher (step S13). The automatic fire extinguisher supplies, for example, water mist, a fire extinguishing agent, carbon dioxide, or the like, into the machining chamber. Information regarding the presence or absence of the automatic fire extinguisher is stored in, for example, the memory installed in machine tool body 1. Identification device 4 acquires the information regarding the presence or absence of the automatic fire extinguisher by communicating with machine tool body 1. Identification device 4 may possess the information in advance regarding the presence or absence of the automatic fire extinguisher. In this case, step S13 is omitted.
[0038] When determining that machine tool body 1 includes an automatic fire extinguisher (YES in step S13), identification device 4 permits machine tool body 1 to machine the workpiece (step S15). When determining that machine tool body 1 does not include an automatic fire extinguisher (NO in step S13), identification device 4 instructs machine tool body 1 to perform first abnormality processing (step S14).
[0039] The first abnormality processing is warning display. Upon receipt of the instruction to perform the first abnormality processing from identification device 4, machine tool body 1 displays a warning on the panel of the control board. Machine tool body 1 may also turn on a warning light. The warning display is not limited thereto and is performed to notify a surrounding person of an abnormality.
[0040] The first abnormality processing may be the execution of interlock control, in addition to or instead of the warning display. Upon receipt of an instruction to perform interlock control from identification device 4, machine tool body 1 stops the execution of the machining program.
[0041] The machine tool can perform the first abnormality processing in this manner to notify a person around machine tool body 1 that an oil-based coolant is used or has been used in machine tool body 1, which is designed for a water-soluble coolant. Furthermore, the execution of interlock control suppresses start of machining using an oil-based coolant even if the oil-based coolant is stored in the coolant tank.
[0042] Fig. 6 is a flowchart of the determination leading to the execution of second abnormality processing in the machine tool. First, identification device 4 identifies the type of the coolant stored in coolant tank 2 (step S21).
[0043] When determining that the coolant stored in coolant tank 2 is a water-soluble coolant (YES in step S21), identification device 4 permits machine tool body 1 to machine the workpiece (step S24). When determining that the coolant stored in coolant tank 2 is an oil-based coolant (NO in step S21), identification device 4 determines whether machine tool body 1 is a machine tool designed for a water-soluble coolant or a machine tool designed for an oil-based coolant (step S22). Steps S21 and S22 may be performed in a reverse order or performed simultaneously. Furthermore, identification device 4 may possess information in advance regarding the specifications of the machine tool body. In this case, step S22 is omitted.
[0044] When determining that machine tool body 1 is a machine tool designed for an oil-based coolant (YES in step S22), identification device 4 permits machine tool body 1 to machine the workpiece (step S24). When determining that machine tool body 1 is a machine tool designed for a water-soluble coolant (NO in step S22), identification device 4 instructs machine tool body 1 to perform the second abnormality processing (step S23).
[0045] The second abnormality processing is processing for suppressing an unattended operation of machine tool body 1. Upon receipt of an instruction from identification device 4 to perform the second abnormality processing, machine tool body 1 stops the machining program at fixed time intervals and restarts the stopped machining program via an input operation by the operator. The input operation by the operator is, for example, a button operation on the control panel.
[0046] As the machine tool performs the second abnormality processing in this manner, start or continuation of machining is suppressed without an operator around machine tool body 1 even though the oil-based coolant is used or has been used in machine tool body 1 designed for a water-soluble coolant.
[0047] Fig. 7 is a flowchart of the determination leading to the execution of third abnormality processing in the machine tool. First, identification device 4 identifies the type of the coolant stored in coolant tank 2 (step S31).
[0048] When determining that the coolant stored in coolant tank 2 is a water-soluble coolant (YES in step S31), identification device 4 permits machine tool body 1 to machine the workpiece (step S34). When determining that the coolant stored in coolant tank 2 is an oil-based coolant (NO in step S31), identification device 4 determines whether machine tool body 1 is a machine tool designed for a water-soluble coolant or a machine tool designed for an oil-based coolant (step S32). Steps S31 and S32 may be performed in a reversed order or performed simultaneously. Furthermore, identification device 4 may possess information in advance regarding the specifications of the machine tool body. In this case, step S32 is omitted.
[0049] When determining that machine tool body 1 is a machine tool designed for an oil-based coolant (YES in step S32), identification device 4 permits machine tool body 1 to machine the workpiece (step S34). When determining that machine tool body 1 is a machine tool designed for a water-soluble coolant (NO in step S32), identification device 4 instructs machine tool body 1 to perform the third abnormality processing (step S33).
[0050] The third abnormality processing is processing for reducing a machining load. Upon receipt of the instruction to perform the third abnormality processing from identification device 4, machine tool body 1 monitors the load of the spindle. The spindle referred to herein means a spindle holding a tool in a machining center, a spindle holding a workpiece in a turning center, and a spindle holding a tool and / or a spindle holding a workpiece in a multi-tasking machine. Machine tool body 1 changes the monitored load of the spindle to a limit value lower than a normal value. The normal value of the load is a preset value. The normal value of the load is appropriately set based on the type of a workpiece, the type of a tool used, machining conditions, or the like.
[0051] As the machine tool performs the third abnormality processing in this manner, machining is performed suitably even when an oil-based coolant is used or has been used in machine tool body 1 designed for a water-soluble coolant.
[0052] <Embodiment 2> For the machine tool according to Embodiment 1 described above, description has been given of the configuration in which the first transmission wave and the second emission wave emitted from the sensor unit are different in signal intensity. For the machine tool according to Embodiment 2, description will be given of the configuration in which the first transmission wave and the second transmission wave have the same signal intensity. In the description below, the components similar to those of Embodiment 1 will be omitted as appropriate.
[0053] Fig. 8 is a diagram schematically showing measurement by the sensor unit when the coolant is a water-soluble coolant in the machine tool of Embodiment 2. Part (A) of the figure shows measurement by first sensor 31, and Part (B) of the figure shows measurement by second sensor 32. Referring to Part (A), sensor unit 3 includes first sensor 31 and second sensor 32, both of which are radar sensors.
[0054] First sensor 31 emits first transmission wave 311 toward bottom surface 21 of coolant tank 2 and receives first liquid level reflected wave 312 reflected off the liquid level of water-soluble coolant C1. First sensor 31 transmits information on the signal intensity of the received first liquid level reflected wave 312 to identification device 4. Herein, part (indicated by the dashed downward arrow in the figure) of first transmission wave 311 is not reflected off the liquid level but passes through water-soluble coolant C1 and is reflected off bottom surface 21 of coolant tank 2. First sensor 31 receives the first bottom surface reflected wave reflected off bottom surface 21. First sensor 31 transmits information on the signal intensity of a received first bottom surface reflected wave 313 to identification device 4.
[0055] Identification device 4 uses information on the signal intensity of first liquid level reflected wave 312, not first bottom surface reflected wave 313, for coolant identification processing. Thus, identification device 4 performs mask processing M1. For example, it is assumed that the height of coolant tank 2 is 300 mm and the liquid level height of water-soluble coolant C1 is 250 mm. Identification device 4 is set in advance to exclude, from coolant identification processing, reflected waves reflected within a height range of 30 mm from bottom surface 21 of coolant tank 2. In other words, identification device 4 is configured such that the information on the signal intensity of first bottom surface reflected wave 313 is not used for coolant identification processing. When the coolant is a water-soluble coolant, identification device 4 is configured such that information on the signal intensity of first liquid level reflected wave 312 is used for coolant identification processing.
[0056] The mask processing method by identification device 4 is not particularly limited. For example, identification device 4 identifies first liquid level reflected wave 312 and first bottom surface reflected wave 313 based on the reception time for the received reflected wave (the distance from the first sensor to the reflection position). Identification device 4 performs mask processing on the identified first bottom surface reflected wave 313. Alternatively, for example, in the case of water-soluble coolant C1, the signal intensity of first liquid level reflected wave 312, which is reflected off the liquid level, is stronger than that of first bottom surface reflected wave 313, which is reflected off bottom surface 21. Thus, identification device 4 may also identify first liquid level reflected wave 312 and first bottom surface reflected wave 313 based on the signal intensity of the received reflected wave.
[0057] Referring to Part (B), second sensor 32 emits second transmission wave 321 toward bottom surface 21 of coolant tank 2. The signal intensity of second transmission wave 321 is the same as that of first transmission wave 311. Second sensor 32 receives second liquid level reflected wave 322, which is a reflected wave generated by second transmission wave 321 being reflected off the liquid level of water-soluble coolant C1. Second sensor 32 transmits, to identification device 4, information on the signal intensity of the received second liquid level reflected wave 322.
[0058] Part (indicated by the dashed downward arrow in the figure) of second transmission wave 321 is not reflected off the liquid level but passes through water-soluble coolant C1 and is reflected off bottom surface 21 of coolant tank 2. Second sensor 32 receives the second bottom surface reflected wave reflected off bottom surface 21, similarly to first sensor 31. First sensor 31 transmits, to identification device 4, information on the signal intensity of the received second bottom surface reflected wave 323.
[0059] Identification device 4 performs processing on the signal received from second sensor 32 ,which is different from processing on the signal received from first sensor 31. Specifically, for the signal received from first sensor 31, identification device 4 performs mask processing to exclude first bottom surface reflected wave 313 reflected off bottom surface 21 of coolant tank 2. In contrast, for the signal received from second sensor 32, identification device 4 does not exclude second bottom surface reflected wave 323 reflected off bottom surface 21 of coolant tank 2.
[0060] However, identification device 4 is set to use the reflected wave of the strongest signal intensity for coolant identification processing, when receiving a plurality of reflected waves. In other words, identification device 4 is set to use one reflected wave for coolant identification processing. Identification device 4 receives both the information on the signal intensity of second liquid level reflected wave 322 and the information on the signal intensity of second bottom surface reflected wave 323 from second sensor 32. Identification device 4 compares the received signal intensity of second liquid level reflected wave 322 with the received signal intensity of second bottom surface reflected wave 323. When the coolant is water-soluble coolant C1, the signal intensity of second liquid level reflected wave 322 is stronger than the signal intensity of second bottom surface reflected wave 323. Thus, although identification device 4 receives both the information on the signal intensity of second liquid level reflected wave 322 and the information on the signal intensity of second bottom surface reflected wave 323, identification device 4 is configured to use the information on the signal intensity of second liquid level reflected wave 322 for coolant identification processing.
[0061] When the same product as first sensor 31 is used as second sensor 32, identification device 4 can set mask processing for second sensor 32, similarly to first sensor 31. It is assumed that the bottom surface of coolant tank 2 is a zero point and the height of coolant tank 2 is +300 mm. In such a case, identification device 4 is set in advance to exclude, from coolant identification processing, reflected waves reflected within the height range of -100 mm from bottom surface 21 (zero point) of coolant tank 2. In other words, identification device 4 sets a virtual region outside coolant tank 2 and performs mask processing on that region. Thus, identification device 4 is set not to ignore (not to mask) reflected waves reflected within coolant tank 2, particularly second bottom surface reflected wave 323.
[0062] Identification device 4 obtains measurement results for the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322. Identification device 4 determines whether the signal intensity of first liquid level reflected wave 312 and the signal intensity of second liquid level reflected wave 322 are each greater than or equal to a threshold or less than the threshold. This threshold is, differently from the threshold in Embodiment 1, a value for the identification device to recognize whether first sensor 31 and second sensor 32 have received the respective reflected waves. In other words, when the coolant is water-soluble coolant C1, identification device 4 recognizes the signal intensities of first liquid level reflected wave 312 and second liquid level reflected wave 322. Specifically, identification device 4 determines, as the measurement result, that both first sensor 31 and second sensor 32 have detected the liquid level of water-soluble coolant C1. Next, the case of an oil-based coolant will be described.
[0063] Fig. 9 is a diagram schematically showing measurement by a sensor unit when the coolant is an oil-based coolant in the machine tool of Embodiment 2. Part (A) of the figure shows measurement by first sensor 31, and Part (B) of the figure shows measurement by second sensor 32. Referring to Part (A), first sensor 31 emits first transmission wave 311 toward bottom surface 21 of coolant tank 2 and receives first liquid level reflected wave 312 reflected off the liquid level of water-soluble coolant C1. First sensor 31 transmits, to identification device 4, information on the signal intensity of the received first liquid level reflected wave 312. First sensor 31 also receives first bottom surface reflected wave 313 reflected off bottom surface 21 of coolant tank 2. First sensor 31 transmits, to identification device 4, information on the signal intensity of the received first bottom surface reflected wave 313.
[0064] As in the case of water-soluble coolant C1 described above, identification device 4 performs mask processing M1 to prevent the information on the signal intensity of first bottom surface reflected wave 313 from being used for coolant identification processing. When the coolant is water-soluble coolant C1, identification device 4 is configured to use the information on the signal intensity of first liquid level reflected wave 312 for coolant identification processing.
[0065] Referring to Part (B), second sensor 32 emits second transmission wave 321 toward bottom surface 21 of coolant tank 2. The signal intensity of second transmission wave 321 is the same as that of first transmission wave 311. Second sensor 32 receives second liquid level reflected wave 322, which is the reflected wave generated by second transmission wave 321 being reflected off the liquid level of oil-based coolant C2. Second sensor 32 transmits, to identification device 4, the information on the signal intensity of the received second liquid level reflected wave 322. Second sensor 32 also receives second bottom surface reflected wave 323 reflected off bottom surface 21 of coolant tank 2. Second sensor 32 transmits, to identification device 4, the information on the signal intensity of the received second bottom surface reflected wave 323.
[0066] As in the case of the water-soluble coolant described above, identification device 4 does not perform mask processing on second bottom surface reflected wave 323. Furthermore, identification device 4 is set to use, when a plurality of reflected waves are received, the reflected wave of the strongest signal intensity for coolant identification processing. Identification device 4 compares the signal intensity of the received second liquid level reflected wave 322 with the signal intensity of second bottom surface reflected wave 323. When the coolant is oil-based coolant C2, the signal intensity of second bottom surface reflected wave 323 is stronger than the signal intensity of second liquid level reflected wave 322. Thus, identification device 4 is configured to use the information on the signal intensity of the received second bottom surface reflected wave 323 for coolant identification processing.
[0067] Identification device 4 obtains measurement results for the signal intensity of first liquid level reflected wave 312 and the signal intensity of second bottom surface reflected wave 323. Identification device 4 determines whether the signal intensity of first liquid level reflected wave 312 and the signal intensity of second bottom surface reflected wave 323 are each greater than or equal to a threshold or less than the threshold. This threshold is, differently from the threshold in Embodiment 1, a value for the identification device to recognize whether first sensor 31 and second sensor 32 have received the respective reflected waves. In other words, when the coolant is oil-based coolant C2, identification device 4 recognizes the signal intensities of first liquid level reflected wave 312 and second bottom surface reflected wave 323. Specifically, identification device 4 determines, as a measurement result, that first sensor 31 has detected the liquid level of oil-based coolant C2 and second sensor 32 has detected the bottom surface of oil-based coolant C2 (bottom surface 21 of coolant tank 2).
[0068] Fig. 10 is a diagram showing the measurement results for a water-soluble coolant and an oil-based coolant in the machine tool of Embodiment 2. When the coolant is a water-soluble coolant, for the signal received from first sensor 31, identification device 4 uses first liquid level reflected wave 312, which is reflected off the liquid level of the water-soluble coolant for identification processing, and excludes first bottom surface reflected wave 313 from bottom surface 21 of coolant tank 2 by mask processing. Thus, identification device 4 recognizes the liquid level of water-soluble coolant C1 based on the signal received from first sensor 31 (the signal intensity of first liquid level reflected wave 312).
[0069] For the signals received from second sensor 32, identification device 4 sets mask processing to be performed outside the coolant tank. Thus, when the coolant is a water-soluble coolant, identification device 4 receives, from second sensor 32, second liquid level reflected wave 322 reflected off the liquid level of the water-soluble coolant and the second bottom surface reflected wave from bottom surface 21 of coolant tank 2. However, identification device 4 uses the reflected wave of the stronger intensity between second liquid level reflected wave 322 and the second bottom surface reflected wave, that is, second liquid level reflected wave 322, for coolant identification processing. Thus, when the coolant is a water-soluble coolant, the measurement results are "LIQUID LEVEL" for first sensor 31 and "LIQUID LEVEL" for second sensor 32, as shown in the figure.
[0070] When the coolant is an oil-based coolant, for the signal received from first sensor 31, identification device 4 uses first liquid level reflected wave 312, which is reflected off the liquid level of the oil-based coolant, for identification processing, and excludes the first bottom surface reflected wave from bottom surface 21 of coolant tank 2 by mask processing. Thus, identification device 4 recognizes the liquid level of oil-based coolant C2 based on the signal received from first sensor 31 (the signal intensity of first liquid level reflected wave 312).
[0071] For the signals received from second sensor 32, identification device 4 sets mask processing to be performed outside the coolant tank. Thus, when the coolant is an oil-based coolant, identification device 4 receives, from second sensor 32, second liquid level reflected wave 322 reflected off the liquid level of the oil-based coolant and second bottom surface reflected wave 323 from bottom surface 21 of coolant tank 2. However, identification device 4 uses the reflected wave of the stronger intensity between second liquid level reflected wave 322 and the second bottom surface reflected wave, that is, second bottom surface reflected wave 323, for coolant identification processing. Thus, when the coolant is an oil-based coolant, the measurement results are "LIQUID LEVEL" for first sensor 31 and "TANK BOTTOM SURFACE" for second sensor 32, as shown in the figure.
[0072] Identification device 4 determines that the coolant stored in coolant tank 2 is a water-soluble coolant when the measurement results are "LIQUID LEVEL-LIQUID LEVEL". Identification device 4 determines that the coolant stored in coolant tank 2 is an oil-based coolant when the measurement results are "LIQUID LEVEL-TANK BOTTOM SURFACE".
[0073] In this way, in the machine tool of Embodiment 2, sensor unit 3 emits two transmission waves of the same signal intensity toward the coolant stored in the coolant tank. Identification device 4 is configured to detect, for the information regarding the reflected waves received from first sensor 31, the liquid level of the coolant. Identification device 4 is configured to detect, for the information regarding the reflected waves received from second sensor 32, the liquid level for a water-soluble coolant and bottom surface 21 of coolant tank 2 for an oil-based coolant. Therefore, machine tool 100 can identify the type of the coolant used in machine tool body 1.
[0074] The machine tool of Embodiment 2 can also perform various pieces of abnormality processing described in the modification of Embodiment 1.
[0075] The embodiments described above have been presented for the purpose of illustration and non-restrictive in every respect. Modifications and variations are readily apparent to a person skilled in the art. The scope of the present invention is defined by claims, rather than the description above. Further, the scope of the present invention encompasses all modifications and variations equivalent in meaning and scope to the claims.
[0076] For example, Embodiments 1 and 2 have described the configuration in which sensor unit 3 includes two sensors, that is, first sensor 31 and second sensor 32. Alternatively, sensor unit 3 may have a configuration including a single sensor. In this case, the single sensor performs the functions of both first sensor 31 and second sensor 32. For example, first, the single sensor may be caused to function as first sensor 31, and after the completion of measurement by first sensor 31, the single sensor may be caused to function as second sensor 32. After being caused to function as second sensor 32, the single sensor may be again caused to function as first sensor 31.
[0077] For example, Embodiments 1 and 2 have described the configuration in which identification device 4 is included in machine tool body 1. However, identification device 4 does not need to be included in machine tool body 1. Identification device 4 may be included in sensor unit 3. Identification device 4 may be provided separately from machine tool body 1 and sensor unit 3.
[0078] For example, Embodiments 1 and 2 have described the configuration in which first sensor 31 and second sensor 32 are radar sensors. However, first sensor 31 and second sensor 32 are not limited thereto. The first sensor and the second sensor may be, for example, guide pulse sensors, ultrasonic sensors, electromagnetic wave sensors, laser light sensors, microwave sensors, or the like. In short, the first sensor and the second sensor may be any sensors utilizing wave properties. The first sensor may be a sensor of the same type as, or different type from, the second sensor.
[0079] For example, Embodiments 1 and 2 have described the configuration in which first sensor 31 functions as a water level sensor. Alternatively, first sensor 31 does not need to function as the water level sensor. First sensor 31 may be a sensor provided separately from the water level sensor.
[0080] For example, description has been given of the configuration in which the signal intensities of first sensor 31 and second sensor 32 in Embodiment 1, and mask processing for first sensor 31 and second sensor 32 in Embodiment 2 are set in machine tool body 1. However, these settings are not limited to the configuration in which they are set in machine tool body 1. These settings may be, for example, set in sensor unit 3 when identification device 4 is mounted in sensor unit 3.
[0081] For example, in Embodiments 1 and 2, the machine tool identifies the coolant type when machine tool body 1 is powered on. However, the machine tool is not limited thereto. The machine tool may identify the coolant type at any timing.
[0082] For example, Embodiments 1 and 2 have described the configuration in which water-soluble coolant C1 or oil-based coolant C2 is stored in coolant tank 2. However, neither of the above coolants may be stored in coolant tank. In other words, coolant tank 2 may be empty. In this case, the measurement results are "NG-NG" in Embodiment 1, and the measurement results are " TANK BOTTOM SURFACE- TANK BOTTOM SURFACE" in Embodiment 2. Thus, in both Embodiments 1 and 2, not only can the type of the coolant stored in coolant tank 2 be identified, but it can also be determined that coolant tank 2 is empty.
[0083] <Embodiment 3> The present embodiment and Embodiment 4, which will be described later, will describe various configurations of machine tool 100 including sensor unit 3.
[0084] Fig. 12 is a block diagram schematically showing a coolant flow in a machine tool in Embodiment 3. Fig. 13 is a top view showing a tank and a chip conveyor in the machine tool of Fig. 12. Fig. 14 is a perspective view partially showing the tank and the chip conveyor in the machine tool of Fig. 12.
[0085] Referring to Figs. 12 to 14, machine tool 100 in the present embodiment is capable of machining while supplying a coolant.
[0086] Machine tool 100 includes a machining unit 510. Machining unit 510 performs machining. Machining unit 510 is the portion of machine tool 100 which machines a workpiece and corresponds to machine tool body 1 described in Embodiments 1 and 2. Machining unit 510 is a machining center that machines a workpiece by bringing a rotating tool into contact with the workpiece. Machining unit 510 is a horizontal machining center, which will be described later, with the rotational center axis of the tool spindle extending horizontally. Machining unit 510 is a numerically controlled (NC) machine tool in which various operations for machining a workpiece are automated through numerical control by a computer.
[0087] Machining unit 510 defines a machining area and includes a cover body constituting the exterior of machining unit 510, a tool spindle disposed in the machining area for rotating a tool, a table disposed in the machining area for holding the workpiece, and a bed forming a foundation supporting the tool spindle and the table.
[0088] Machine tool 100 further includes a chip conveyor 520 and a tank 600. Chip conveyor 520 discharges chips and a coolant generated due to machining (workpiece machining) in machining unit 510 to the outside of machining unit 510. Tank 600 is formed of a box body capable of storing a coolant. Tank 600 is provided on the floor surface of a factory or the like where machining unit 510 is provided. Tank 600 is provided adjacent to machining unit 510. Chip conveyor 520 is housed in tank 600.
[0089] As shown in Fig. 14, chip conveyor 520 includes a cover portion 521. Cover portion 521 forms the exterior of chip conveyor 520. A conveyance device (not shown) for conveying chips is housed in cover portion 521.
[0090] Cover portion 521 is provided with a reception port 531 and a discharge port 532. Reception port 531 is open upward. Discharge port 532 is open downward at a position offset horizontally from reception port 531. Discharge port 532 is offset from tank 600 in top view. A chip bucket (not shown) for collecting chips is provided directly below discharge port 532.
[0091] Fig. 13 shows a first direction 210 and a second direction 220 indicated by the arrows. First direction 210 is parallel to the horizontal direction. Second direction 220 is parallel to the horizontal direction and perpendicular to first direction 210. When tank 600 is provided adjacent to machining unit 510, first direction 210 corresponds to the axial direction of the rotation axis of the tool spindle.
[0092] As shown in Fig. 13, tank 600 includes a first tank portion 610, a second tank portion 620, and a third tank portion 630. First tank portion 610, second tank portion 620, and third tank portion 630 correspond to a plurality of regions obtained by dividing tank 600 in top view.
[0093] First tank portion 610 is in communication with second tank portion 620. Third tank portion 630 is isolated from first tank portion 610 and second tank portion 620. First tank portion 610 extends in first direction 210. The length of first tank portion 610 in first direction 210 is larger than the length of first tank portion 610 in second direction 220. In top view, first tank portion 610 has a rectangular shape in which first direction 210 corresponds to the longitudinal direction and second direction 220 corresponds to the transverse direction.
[0094] Chip conveyor 520 is housed in first tank portion 610. In Fig. 13 and Fig. 16, which will be referred to later, reception port 531 is indicated by the chain double-dashed line. Reception port 531 overlaps first tank portion 610 in top view. Reception port 531 has a rectangular shape in top view, in which first direction 210 corresponds to the longitudinal direction and second direction 220 corresponds to the transverse direction.
[0095] As shown in Figs. 13 and 14, chip conveyor 520 further includes a drum filter 522. Drum filter 522 is housed in cover portion 521.
[0096] Drum filter 522 has a cylindrical shape centered on a rotation center axis 101. Rotation center axis 101 extends in the horizontal direction (second direction 220). Drum filter 522 has a first end 522p and a second end 522q. Drum filter 522 extends cylindrically between first end 522p and second end 522q.
[0097] Drum filter 522 is supported inside cover portion 521 so as to rotate about rotation center axis 101. Drum filter 522 is driven to rotate about rotation center axis 101 by power transmitted from a conveyance device (not shown).
[0098] Drum filter 522 is provided in the path for a coolant flow from first tank portion 610 to second tank portion 620. Drum filter 522 is disposed in first tank portion 610. Drum filter 522 is provided in second direction 220 closer to the second end (the right end in the paper of Fig. 13) of first tank portion 610 in second direction 220 than to the first end (the left end in the paper of Fig. 13) of first tank portion 610 in second direction 220. In top view, drum filter 522 is provided side by side with reception port 531 in first direction 210.
[0099] Second tank portion 620 is provided side by side with first tank portion 610 in second direction 220. Second tank portion 620 is positioned closer to the second end of first tank portion 610 in second direction 220 than to the first end of first tank portion 610 in second direction 220.
[0100] Tank 600 has a first side wall 641j and a second side wall 641k. First side wall 641j and second side wall 641k rise from the bottom surface of tank 600 to form wall shapes. First side wall 641j and second side wall 641k are spaced apart from each other in first direction 210.
[0101] Second tank portion 620 is defined between first side wall 641j and second side wall 641k. Tank 600 further has a partition wall 642. Partition wall 642 forms the boundary between first tank portion 610 and second tank portion 620. Partition wall 642 extends in first direction 210 from first side wall 641j toward second side wall 641k. An opening 643 is provided between partition wall 642 and first side wall 641j. Opening 643 faces first end 522p of drum filter 522 in second direction 220 (the axial direction of rotation center axis 101). First end 522p is positioned in second direction 220 between opening 643 and second end 522q. First tank portion 610 is in communication with second tank portion 620 through opening 643.
[0102] Third tank portion 630 is provided side by side with first tank portion 610 in second direction 220. Third tank portion 630 is provided side by side with second tank portion 620 in first direction 210 and second direction 220. Second tank portion 620 is provided between first tank portion 610 and third tank portion 630 in second direction 220. The length of third tank portion 630 in first direction 210 is the same as the length of third tank portion 630 in first direction 210. The length of third tank portion 630 in first direction 210 may be larger or smaller than the length of third tank portion 630 in first direction 210. First tank portion 610 and third tank portion 630 are provided around second tank portion 620.
[0103] As shown in Figs. 12 and 13, machine tool 100 further includes a first pump 710, a foreign matter treatment device 760, and a second pump 720.
[0104] First pump 710 is provided in second tank portion 620. First pump 710 may be positioned so as to face partition wall 642 or face opening 643 in second direction 220. First pump 710, which is an immersion pump, includes a pump portion (not shown) immersed in the coolant stored in second tank portion 620. First pump 710 pumps the coolant stored in second tank portion 620 toward foreign matter treatment device 760.
[0105] Foreign matter treatment device 760 is a device for treating a foreign matter such as chips or sludge contained in the coolant. Foreign matter treatment device 760 captures a foreign matter contained in the coolant from first pump 710. Foreign matter treatment device 760 may be of a filterless type that does not include a filtration filter. Foreign matter treatment device 760 may be a cyclone separator that captures a foreign matter by centrifugal force.
[0106] An inflow portion 270 is set in third tank portion 630. The coolant with the foreign matter treated by foreign matter treatment device 760 flows into inflow portion 270. Inflow portion 270 is connected with a hose or a pipe, such as a steel pipe, which extends from foreign matter treatment device 760 and through which the coolant with the foreign matter treated by foreign matter treatment device 760 flows.
[0107] Second pump 720 is provided in third tank portion 630. Second pump 720, which is an immersion pump, includes a pump portion (not shown) immersed in the coolant stored in third tank portion 630. Second pump 720 pumps the coolant stored in third tank portion 630 toward machining unit 510.
[0108] The chips and coolant generated in machining unit 510 are received inside cover portion 521 through reception port 531. The chips are conveyed by the conveyance device from reception port 531 toward discharge port 532. The chips are discharged to the outside of cover portion 521 through discharge port 532 and are collected in the chip bucket.
[0109] On the other hand, the coolant received inside cover portion 521 flows in first direction 210 in first tank portion 610. The coolant flows from the first end of first tank portion 610 in first direction 210 toward the second end of first tank portion 610 in first direction 210. The coolant flows toward drum filter 522. The coolant is filtered by entering the interior of drum filter 522 from the outside thereof. Inside drum filter 522, the coolant changes the flow direction from first direction 210 to second direction 220 and flows toward first end 522p. The coolant exits drum filter 522 through first end 522p. The coolant flows from first tank portion 610 through opening 643 to second tank portion 620 located beyond the position at which the coolant passes through first end 522p.
[0110] First pump 710 pumps the coolant that has flowed to second tank portion 620 toward foreign matter treatment device 760. Foreign matter treatment device 760 treats a foreign matter contained in the coolant from first pump 710. The coolant with the foreign matter treated by foreign matter treatment device 760 is supplied to third tank portion 630 through inflow portion 270. Second pump 720 supplies the coolant stored in third tank portion 630 toward machining unit 510.
[0111] As shown in Fig. 13, machine tool 100 further incudes sensor unit 3 (first sensor 31, second sensor 32) described in Embodiments 1 and 2.
[0112] Sensor unit 3 (first sensor 31, second sensor 32) is provided in tank 600. First sensor 31 and second sensor 32 are capable of sensing the coolant in tank 600. First sensor 31 and second sensor 32 are capable of applying a laser toward the coolant stored in tank 600.
[0113] Sensor unit 3 (first sensor 31, second sensor 32) is provided in third tank portion 630. First sensor 31 and second sensor 32 are capable of sensing the coolant in third tank portion 630. First sensor 31 and second sensor 32 are capable of applying a laser toward the coolant stored in third tank portion 630.
[0114] Sensor unit 3 (first sensor 31, second sensor 32) is provided between inflow portion 270 and second pump 720 in top view. First sensor 31 and second sensor 32 are capable of applying a laser toward the coolant flowing from inflow portion 270 toward second pump 720. In top view, the distance between sensor unit 3 and inflow portion 270 may be larger than or equal to the distance between sensor unit 3 and second pump 720, or may be less than the distance between sensor unit 3 and second pump 720.
[0115] <Embodiment 4 > Fig. 15 is a block diagram schematically showing a coolant flow in a machine tool in Embodiment 4. Fig. 16 is a top view showing a tank and a chip conveyor in the machine tool of Fig. 15. Fig. 17 is a sectional view showing a secondary tank in the machine tool of Fig. 15.
[0116] Machine tool 100 in the present embodiment has a structure basically similar to that of machine tool 100 in Embodiment 3. An overlapping structure will not be repeatedly described below.
[0117] Referring to Figs. 15 to 17, in the present embodiment, machining unit 510 is a multi-tasking machine having a turning function and a milling function.
[0118] Machining unit 510 includes a cover body that defines a machining area and constitutes the exterior of machining unit 510, a tool spindle disposed in the machining area for rotating a tool, a workpiece spindle disposed in the machining area for rotating a workpiece, a tool rest disposed in the machining area for holding a tool, and a bed that forms a foundation supporting the tool spindle, the workpiece spindle, and the tool rest.
[0119] In Fig. 16, first direction 210 and second direction 220 are indicated by the arrows. With a primary tank 600A, which will be described later, being provided adjacent to machining unit 510, first direction 210 corresponds to the axial direction of the rotation axis of the workpiece spindle.
[0120] The machining unit in the present invention is not limited to the machining center and the multi-tasking machine described in Embodiments 3 and 4, respectively. The machining unit in the present invention may be, for example, a lathe that machines a workpiece by bringing a tool into contact with a rotating workpiece, or an additive manufacturing (AM) / subtractive manufacturing (SM) hybrid processing machine capable of additive manufacturing of workpieces and subtractive manufacturing of workpieces.
[0121] Tank 600 includes primary tank 600A and a secondary tank 600B. Each tank of primary tank 600A and secondary tank 600B is formed of a box body capable of storing the coolant.
[0122] Primary tank 600A is provided on the floor surface of a factory or the like where machining unit 510 is provided. Primary tank 600A is provided adjacent to machining unit 510. Chip conveyor 520 is housed in primary tank 600A. Secondary tank 600B is provided as a separate tank from primary tank 600A. Secondary tank 600B is provided above primary tank 600A. In top view, secondary tank 600B may be positioned so as to overlap primary tank 600A or may be positioned so as to be offset from primary tank 600A.
[0123] As shown in Figs. 15 and 16, primary tank 600A includes a first tank portion 810 and a second tank portion 820. First tank portion 810 and second tank portion 820 correspond to a plurality of regions obtained by dividing primary tank 600A in top view. First tank portion 810 and second tank portion 820 correspond to first tank portion 610 and second tank portion 820, respectively, in Embodiment 3. Chip conveyor 520 (drum filter 522) is housed in first tank portion 610.
[0124] As shown in Fig. 17, secondary tank 600B has a side wall 811 and an inclined wall 812. Inclined wall 812 forms a wall shape inclined relative to the vertical direction such that the area of the opening of secondary tank 600B, which is obtained by cutting along a horizontal plane, becomes smaller from top to bottom. The lower end of inclined wall 812 is connected with pipe 731. Side wall 811 rises from the upper end of inclined wall 812 to form a wall shape.
[0125] Secondary tank 600B includes a fourth tank portion 840 and a third tank portion 830. Fourth tank portion 840 and third tank portion 830 correspond to a plurality of regions obtained by dividing secondary tank 600B in top view. Third tank portion 830 is provided in top view so as to surround fourth tank portion 840. Fourth tank portion 840 is provided above pipe 731.
[0126] Secondary tank 600B further has a partition wall 813. Partition wall 813 is provided for partitioning into fourth tank portion 840 and third tank portion 830. Partition wall 813 extends vertically directly above inclined wall 812. A gap is provided between the lower end of partition wall 813 and inclined wall 812.
[0127] Machine tool 100 further includes a first pump 910, a second pump 920, and foreign matter treatment device 760.
[0128] First pump 910 is provided in primary tank 600A. First pump 910 is provided in second tank portion 820. First pump 910 may be positioned 220 so as to face partition wall 642 or face opening 643 in second direction. First pump 910 is an immersion pump and includes a pump portion (not shown) immersed in the coolant stored in second tank portion 820. First pump 910 pumps the coolant stored in the second tank portion 820 toward secondary tank 600B (fourth tank portion 840).
[0129] Second pump 920 is provided below secondary tank 600B. Second pump 920 is provided in the coolant pipeline connecting secondary tank 600B to foreign matter treatment device 760. Second pump 920 is provided below secondary tank 600B. Pipe 731 is connected to second pump 920. Second pump 920 pumps the coolant from secondary tank 600B toward foreign matter treatment device 760.
[0130] Foreign matter treatment device 760 is provided above secondary tank 600B. Foreign matter treatment device 760 is connected with a pipe 761. The coolant with the foreign matter treated by foreign matter treatment device 760 is supplied to third tank portion 830 through pipe 761.
[0131] Third pump 930 is provided in third tank portion 830. Third pump 930 is an immersion pump and includes a pump portion (not shown) immersed in the coolant stored in third tank portion 830. Third pump 930 pumps the coolant stored in third tank portion 830 toward machining unit 510.
[0132] First pump 910 supplies the coolant that has flowed to second tank portion 820 toward fourth tank portion 840 of secondary tank 600B. The foreign matter contained in the coolant stored in secondary tank 600B sinks along inclined wall 812 and collects in pipe 731. Second pump 920 supplies the coolant stored in secondary tank 600B toward foreign matter treatment device 760. Foreign matter treatment device 760 treats the foreign matter contained in the coolant from second pump 920. The coolant with the foreign matter treated by foreign matter treatment device 760 is returned to third tank portion 830 of secondary tank 600B through pipe 761. Third pump 930 supplies the coolant stored in third tank portion 830 toward machining unit 510.
[0133] Machine tool 100 further includes sensor unit 3 (first sensor 31, second sensor 32) as described in Embodiments 1 and 2.
[0134] Sensor unit 3 (first sensor 31, second sensor 32) is provided in tank 600. Sensor unit 3 (first sensor 31, second sensor 32) is provided in secondary tank 600B. First sensor 31 and second sensor 32 are capable of sensing the coolant in tank 600 (secondary tank 600B). First sensor 31 and second sensor 32 are capable of applying a laser toward the coolant stored in tank 600 (secondary tank 600B).
[0135] Sensor unit 3 (first sensor 31, second sensor 32) is provided in third tank portion 830. First sensor 31 and second sensor 32 are capable of sensing the coolant in third tank portion 830. First sensor 31 and second sensor 32 are capable of applying a laser toward the coolant stored in third tank portion 830.
[0136] The position at which the sensor is provided in the present invention is not particularly limited. In Embodiment 3, sensor unit 3 (first sensor 31, second sensor 32) may be provided in second tank portion 620 into which the coolant flows from drum filter 522. Alternatively, in Embodiment 4, sensor unit 3 (first sensor 31, second sensor 32) may be provided in second tank portion 820 into which the coolant from drum filter 522 flows or may be provided in fourth tank portion 840 into which the coolant from second tank portion 820 flows.
[0137] To summarize the configuration of machine tool 100 in each of Embodiments 3 and 4 described above, a machine tool (100) in the present embodiment is a machine tool capable of machining while supplying a coolant. The machine tool (100) includes: a machining unit (510) that performs machining; a tank (600) including (i) a first tank portion (610, 810) in which the coolant that has flowed from the machining unit (510) flows toward a drum filter (522), and (ii) a second tank portion (620, 820) located beyond a position at which the coolant that has flowed to the drum filter (522) and flowed while changing a flow direction toward an end (522) of the drum filter (522) flows through the end (522p); and a sensor (31, 32) that senses the coolant in the tank (600) for identifying whether the coolant is a water-soluble coolant or an oil-based coolant.
[0138] With this configuration, whether the coolant in the tank (600) is a water-soluble coolant or an oil-based coolant can be identified through sensing by the sensor (31, 32).
[0139] The sensor (31, 32) may sense the coolant that has flowed through the drum filter (522). With this configuration, the sensor (31, 32) can sense a cleaner coolant, thereby identifying more accurately whether the coolant is a water-soluble coolant or an oil-based coolant.
[0140] The machine tool (100) may further include a foreign matter treatment device (760) that treats a foreign matter contained in the coolant. The sensor (31, 32) may sense the coolant that has flowed through the foreign matter treatment device (760). With this configuration, the sensor (31, 32) can sense a cleaner coolant, thereby identifying more accurately whether the coolant is a water-soluble coolant or an oil-based coolant.
[0141] This nonprovisional application is based on Japanese Patent Application No. 2025-039075 filed on March 12, 2025 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.
[0142] 1 machine tool body; 2 coolant tank; 3 sensor unit; 4 identification device; 11 machining chamber; 21 bottom surface; 22 primary tank; 23 secondary tank; 24 pump; 25 chip conveyor; 26 discharge port; 31 first sensor; 32 second sensor; 100 machine tool; 101 rotation center axis; 210 first direction; 220 second direction; 270 inflow portion; 311 first transmission wave; 312 first liquid level reflected wave; 313 first bottom surface reflected wave; 321 second transmission wave; 322 second liquid level reflected wave; 323 second bottom surface reflected wave; 510 machining unit; 520 chip conveyor; 532 discharge port; 521 cover portion; 522 drum filter; 522p first end; 522q second end; 531 reception port; 600 tank; 600A primary tank; 600B secondary tank; 610, 810 first tank portion; 620, 820 second tank portion; 630, 830 third tank portion; 641j first side wall; 641k second side wall; 642, 813 partition wall; 643 opening; 710, 910 first pump; 720, 920 second pump; 731, 761 pipe; 760 foreign matter treatment device; 811 side wall; 812 inclined wall; 840 fourth tank portion; 930 third pump; C coolant; C1 water-soluble coolant; C2 oil-based coolant.
Claims
1. A machine tool that performs machining while supplying a coolant, the machine tool comprising: a machining unit that performs machining; a tank including (i) a first tank portion in which the coolant that has flowed from the machining unit flows toward a drum filter, and (ii) a second tank portion located beyond a position at which the coolant that has flowed to the drum filter and flowed while changing a flow direction toward an end of the drum filter flows through the end; and a sensor that senses the coolant in the tank for identifying whether the coolant is a water-soluble coolant or an oil-based coolant.