Coolant tank, and machine tool

Abstract

To provide a coolant tank which allows an operator to easily grasp an amount of a solid component separated from processing object liquid including floating oil, the solid component, and a coolant, and allows disposal work or the like of the solid component or the like separated at proper timing.SOLUTION: A coolant tank comprises: a storage tank TN2 which stores a coolant passed through a processing region where processing of a workpiece is performed; a liquid circulation pipe 1 which includes a suction port 11 for sucking processing object liquid including floating oil, a solid component and the coolant from a liquid surface or the vicinity of the liquid surface of the coolant in the storage tank TN2, and a discharge port 12 for discharging the processing object liquid; a filter 41 which filters the solid component from the processing object liquid discharged from the discharge port 12 of the liquid circulation pipe 1; and a separation tank 5 which separates the processing object liquid passed through the filter 41 into the floating oil and the coolant. The discharge port 12 of the liquid circulation pipe 1 is opened to atmosphere, and the filter 41 is separated to an external side with respect to the discharge port.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a coolant tank used in a machine tool.

Background Art

[0002] For example, when performing metal processing, a coolant is used to cool the workpiece during cutting, improve the lubricity between the tool and the workpiece to improve the machinability, or discharge chips from the processing area to the outside for automation. In a machine tool, a coolant is supplied to the processing area and other places by a device called a coolant tank, and the coolant used in the processing area is refluxed to the coolant tank. The coolant tank separates components such as chips and machine oil used for the sliding parts of the machine tool from the used coolant, makes it a clean coolant, and reuses it for supply to the processing area.

[0003] Here, when the used coolant is stored in the storage tank, a part of the components such as machine oil with a low specific gravity floats on the liquid surface. Such oil components are called floating oil, etc., and for example, a float-type recovery mechanism as shown in Patent Document 1 is used. This device includes a float floating on the liquid surface of the stored used coolant and a pipe having a suction port opening at or near the liquid surface, and the floating oil floating on the coolant liquid surface is recovered using a pump.

[0004] By the way, not only floating oil but also floating sludge composed of fine metal particles, etc. exists on the coolant liquid surface. For this reason, a processing target liquid containing floating oil, floating sludge, and coolant is sucked from the suction port. These components need to be separated individually and reused or discarded. For this reason, a mechanism such as a Y-type strainer is provided in the liquid flow pipe through which the processing target liquid flows, and first, the floating sludge is separated from the processing target liquid.

[0005] When a strainer is used to collect floating sludge in a liquid flow pipe in this way, clogging occurs, so maintenance such as removing the strainer from the pipe and discarding the floating sludge collected inside becomes necessary. However, since the state inside the pipe is not visible, it is difficult for the operator to grasp when maintenance should be performed. For example, depending on the processing content, the amount of floating sludge generated may increase rapidly. In such a case, even if maintenance is performed regularly, it becomes difficult to recover floating oil, etc. before that, and the quality of the coolant supplied to the processing area may deteriorate. On the other hand, if the maintenance frequency is excessively high, it can also become an obstacle when automating processing by a machine tool.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the above-described problems, and makes it easy for an operator to grasp the amount of solid components separated from a processing target liquid containing floating oil, solid components, and coolant, and enables waste disposal operations, etc. of the separated solid components, etc. at an appropriate timing. An object is to provide a coolant tank and a machine tool using the same.

Means for Solving the Problems

[0008] That is, the coolant tank according to the present invention includes a storage tank for storing coolant that has passed through the processing area where the workpiece is processed, a suction port for sucking floating oil, solid components, and a processing target liquid containing coolant from the liquid level or near the liquid level of the coolant in the storage tank, a liquid flow distribution pipe having a discharge port through which the processing target liquid is discharged, a filter for filtering solid components from the processing target liquid discharged from the discharge port of the liquid flow distribution pipe, and a separation tank for separating the processing target liquid that has passed through the filter into floating oil and coolant, wherein the discharge port of the liquid flow distribution pipe is open to the atmosphere, and the filter is provided at a distance outside the discharge port.

[0009] If it is such a thing, since the said filter can be provided outside a pipe | tube, the quantity of the solid content on the said filter isolate | separated from the process target liquid can be grasped easily. For this reason, an operator can judge correctly the necessity of maintenance of the said filter, and can implement maintenance at an appropriate timing.

[0010] In order to make it difficult for the processing target liquid discharged from the discharge port to scatter around and to easily visually recognize the clogging state of the filter, etc., the filter is provided on the lower side, and an opening through which the processing target liquid discharged from the discharge port of the liquid flow distribution pipe flows in is provided on the upper side. It suffices if it is provided with a recovery container having the above.

[0011] In order to make it difficult for the processing target liquid to generate droplets, etc. with respect to the liquid level of the separation tank, to easily maintain the separation state of the floating oil and the coolant, and to prevent the droplets from flowing into the discharge part where droplets are not assumed and the separation accuracy from decreasing, the recovery container is detachably provided with respect to the separation tank, and a cylindrical wall for guiding the processing target liquid passing through the filter to the separation tank side is formed on the outlet side of the filter.

[0012] When the liquid to be processed after the solid components are separated is used as floating oil and coolant, for example, the difference in their specific gravities is utilized to separate them vertically. That is, at the reference water level, a drain outlet for the coolant is formed below the interface between the floating oil and the coolant, and a drain outlet for the floating oil is formed above the interface, and they are discharged in a separated state. By the way, in recent years, the purpose of using the coolant has become various things such as not only cooling the workpiece and tool during processing but also discharging chips, and the amount used per unit time has also increased. Along with this, the amount of the liquid to be processed that is refluxed in the coolant tank and sucked to separate the floating oil and solid components has also increased. For this reason, the fluctuation of the flow rate of the liquid to be processed also becomes large. Therefore, if the gap between the height of the drain outlet for the coolant and the height of the drain outlet for the floating oil is made the same as in the past, a situation may occur where the coolant also flows out from the drain outlet for the floating oil. On the other hand, if the gap is made too large, the time until the floating oil is separated and discharged to the outside will also become long, and the period during which the floating oil recovery mechanism in the coolant tank seems not to be operating will become long. Then, even if the separation function of the floating oil and the coolant is actually operating normally, it may be suspected that some kind of failure has occurred, and it is conceivable that the user's trust in the coolant tank will be damaged.

[0013] To solve such problems, another aspect of the coolant tank according to the present invention is configured to be able to shorten the time until each component is separated from the separation tank and discharged even when the flow rate of the liquid to be processed and its fluctuation amount are large. That is, the separation tank includes a storage section where the liquid to be processed that has passed through the filter is stored, a first discharge section through which the coolant separated in the storage section flows out to the outside, and a second discharge section through which the floating oil separated in the storage section flows out to the outside. The first discharge section is formed so as to extend in the horizontal direction with respect to the main body partition forming the storage section, and includes a first inflow opening through which the coolant flows in, a buffer section where the coolant flowing in from the inflow opening stays, and a first discharge port formed with respect to an outer partition forming the buffer section outside the main body partition, through which the coolant is discharged to the outside. With such a structure, even if the first discharge port is fixed in a shape and size determined by standards such as a socket for connecting a pipe, the height at which the coolant is discharged to the outside and its flow rate can be formed by the first inflow opening. Therefore, even when the flow rate of the liquid to be processed and its fluctuation are large, it is easy to reduce the gap between the height at which the floating oil is discharged and the height at which the coolant is discharged in the separation tank.

[0014] Even when the flow rate of the liquid to be processed is large, in order to make it difficult for the water level of the coolant to rise rapidly and to easily reduce the gap between the heights at which the floating oil and the coolant are discharged, the flow path cross-sectional area of the first inflow opening may be larger than the flow path cross-sectional area of the first discharge opening.

[0015] In order to be able to easily construct a pipe configuration for reusing the separated coolant within the processing area, the first discharge port may be formed by a socket to which a pipe is connected.

[0016] As a specific aspect in which the floating oil is discharged from the separation tank, the second discharge portion is formed to extend in the horizontal direction with respect to the main body partition wall forming the storage portion, and includes a second inflow opening into which the floating oil flows. The lower end height of the second inflow opening is set higher than the height of the lower end of the first inflow opening.

[0017] In order to prevent the droplets of the liquid to be treated discharged from the discharge port of the liquid flow pipe and the droplets generated on the liquid surface in the separation tank from flowing into the second discharge portion, and to prevent a decrease in the separation accuracy of the floating oil and the coolant, the separation tank further includes a support portion that supports the recovery container. The recovery container is configured such that the filter is disposed on the side of the first discharge portion rather than the second discharge portion in a state of being supported by the support portion.

[0018] In order to prevent the liquid to be treated from continuously flowing out from the discharge port of the liquid flow pipe due to the water head in the tank even when the pump suddenly stops, it is sufficient to further include a pump provided in the middle of the liquid flow pipe and a ventilation pipe connecting between the discharge side of the pump in the liquid flow pipe and the upper air layer in the storage tank. In such a case, when the pump stops, air naturally flows into the discharge side, and the outflow of the liquid to be treated due to siphon can be prevented.

[0019] In order to be able to stop the temporary outflow of the liquid to be treated from the discharge port during maintenance of the filter or the like, it is sufficient to further include an on-off valve provided between the pump and the discharge port with respect to the liquid flow pipe.

[0020] In the case of a machine tool including the coolant tank according to the present invention and a splash guard in which the machining area is formed inside, the operator can easily visually recognize the degree of clogging of the filter or the like, so that maintenance can be performed at an appropriate timing, and it is easy to realize a highly automated machining process.

Effects of the Invention

[0021] Thus, in the coolant tank according to the present invention, since the discharge port of the liquid flow pipe is open to the atmosphere and the filter is provided at a distance from the discharge port to the outside, the filter can be exposed to the atmosphere, and the clogging state of the filter can be checked as appropriate. For this reason, even if there are fluctuations in the processing process, the filter can be maintained at an appropriate timing, and the separation accuracy of floating oil and floating sludge can be kept high.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0023] Hereinafter, a coolant tank 100 according to an embodiment of the present invention and a machine tool 200 using the same will be described with reference to the drawings.

[0024] Figure 1 shows the appearance of the machine tool 200. The "machine tool" referred to in this specification is a concept that encompasses various devices having a function of processing workpieces. In this specification, as an example of the machine tool 200, a horizontal machining center will be described as an example, but the machine tool 200 is not limited thereto. For example, the machine tool 200 may be a vertical machining center. Further, the machine tool 200 may be a turning center, a 5-axis machining machine, or a composite machining machine. In addition, the machine tool 200 may be a grinding machine or other cutting machine. Also, the processing is not a concept that includes only subtractive processing, but may also include additive processing.

[0025] As shown in FIG. 1, the machine tool 200 includes a cover body that partitions the inside and outside of the machine and an operation panel. In this machine tool 200, a processing area where cutting processing is performed is provided inside the machine, and a standby area partitioned by an inner door and where the next workpiece waiting for processing is placed on a pallet is set inside.

[0026] The cover body is also called a splash guard, forms the appearance of the machine tool 200, and separates the inside and outside of the machine.

[0027] The operation panel is constituted by, for example, a general-purpose computer, and includes an upper housing and a lower housing that are rotatably connected to each other by a hinge mechanism at the central part.

[0028] Next, a configuration regarding a coolant circuit formed by a coolant tank 100 used in the machine tool 200 of the present embodiment will be described with reference to FIG. 2. In FIG. 2, in order to make the functional connection clear, there may be descriptions different from the actual arrangement of the devices. Therefore, FIG. 2 may not accurately represent the structure, size, position, etc. of each device. Also, descriptions of mechanisms usually used in machine tools such as the table, ATC, and CNC in the machine tool 200 are omitted, but for example, existing ones can be used.

[0029] As shown in Fig. 2, this coolant circuit circulates coolant between the inside and outside of the machine tool 200. It collects the coolant (hereinafter also referred to as dirty coolant) used inside the machine tool and containing chips, lubricating oil, etc. and contaminated, removes the chips and lubricating oil to make the coolant (hereinafter also referred to as clean coolant), and is configured to supply it back into the machine tool again.

[0030] This coolant circuit includes a discharge mechanism 2 that discharges coolant inside the machine tool, a chip conveyor 3 that removes chips and the like from the dirty coolant used and collected inside the machine tool and discards them to the outside, a planar recovery tank TN1 in which the coolant from which chips have been removed in the chip conveyor 3 is stored, a vertical storage tank TN2 to which the dirty coolant from which chips have been removed from the recovery tank TN1 is transferred and stored, and a pump device PP that pumps the clean coolant purified by various separation mechanisms (not shown) provided in the storage tank TN2 or at a subsequent stage thereof to each discharge mechanism 2. And the coolant is configured to circulate within such a coolant circuit. Further, the coolant tank 100 of the present embodiment further includes an oil separation mechanism OS that recovers and separates floating oil, such as lubricating oil or machine oil, which is a different type of oil from the coolant and floats on the liquid level of the dirty coolant stored in the storage tank TN2.

[0031] Each part will be described in detail. The discharge mechanism 2 provided inside the machine tool 200 is provided in a manner corresponding to various usage purposes. To represent and explain some of them, the discharge mechanism 2 includes one provided on the ceiling part to supply a shower coolant, one for flowing the chips in the chip receiver provided at the lower part of the machine tool 200 to the chip conveyor 3, one for discharging the coolant from the tip of the tool TL to lubricate and cool during machining, and so on. There are also various uses in applications not described, and the discharge mechanism 2 is provided at corresponding positions accordingly. The discharge mechanism 2 is configured as a nozzle, for example, and the coolant pressurized by the pump device PP is sprayed into the machine. In the following description, the through-spindle coolant mechanism ST among the discharge mechanisms 2 will be described as an example. The through-spindle coolant mechanism ST is provided with a through-passage for the tool TL and the main spindle S, and the coolant is directly discharged from the tip of the tool TL to the machining point and the like. In the first embodiment, for example, the operator can adjust the pressure so that the coolant is discharged from the tip of the tool TL at an appropriate pressure according to the machining process and machining conditions.

[0032] The chip conveyor 3 scrapes out the chips contained in the coolant by a conveyor housed in the housing and discharges them to, for example, a chip bucket arranged outside the machine. Further, a cylindrical metal drum filter 31 for filtering out minute metal pieces and the like is provided inside the chip conveyor 3. The coolant that has passed through the drum filter 31 is configured to flow into the recovery tank TN1.

[0033] The recovery tank TN1 is provided side by side in the width direction (the back side of the paper surface) of the chip conveyor 3 at the lower part of the machine tool 200. For clarity, in FIG. 2, it is shown as being continuous in the longitudinal direction of the chip conveyor 3. The coolant recovered in the recovery tank TN1 is pumped up to the upper side of the subsequent storage tank TN2 by a transfer pump.

[0034] The storage tank TN2 functions as a buffer for the coolant, and the clean coolant that has passed through the storage tank TN2 is pumped by the pump device PP to each discharge mechanism 2. Note that for clarity, FIG. 2 shows only the flow path L between the through spindle mechanism ST and the pump device PP, but the other discharge mechanisms 2 and the storage tank TN2 are connected. A pressure sensor PS and a flow rate sensor FM are respectively provided on the flow path L as fluid sensors for measuring the pressure or flow rate of the coolant discharged as the through spindle coolant.

[0035] The rotation speed of the pump device PP is controlled by changing the frequency of the current input from the inverter 5. In the present embodiment, the frequency output by the inverter (not shown) is controlled by pressure feedback control so that the deviation between the measured pressure measured by the pressure sensor PS and the set pressure which is the set value becomes small.

[0036] Next, the details of the oil separation mechanism OS will be described with reference to FIGS. 2 to 5. The oil separation mechanism OS sucks floating oil and floating sludge such as fine metal powder that floats on the liquid surface of the dirty coolant in the storage tank TN2, and is responsible for part of the separation operation necessary to make the clean coolant. This oil separation mechanism OS sucks the floating oil, floating sludge, and the liquid to be treated including the coolant from the liquid surface or near the liquid surface of the coolant stored in the storage tank TN2. Then, first, the floating sludge which is a solid component is separated from the sucked liquid to be treated, and further, the floating oil and the coolant are separated from the liquid to be treated from which the floating sludge has been separated. More specifically, the oil separation mechanism OS includes a suction port 11 for sucking the liquid to be treated from the liquid surface or near the liquid surface of the coolant in the storage tank TN2, and a discharge port 12 from which the sucked liquid to be treated is discharged, a liquid flow distribution pipe 1 through which the liquid to be treated flows, and a recovery container 4 provided at a predetermined distance from the discharge port 12 of the liquid flow distribution pipe 1 and including a filter 41 for separating solid components such as floating sludge from the liquid to be treated, and a separation tank 5 in which the liquid to be treated that has passed through the filter 41 of the recovery container 4 is stored and the floating oil and the coolant are separated due to the difference in their specific gravities.

[0037] The liquid circulation pipe 1 is made of a flexible material at least on the side of the storage tank TN2, and the position of the suction port 11 can be changed according to the liquid level of the coolant in the storage tank TN2. A float 1F is provided near the suction port 11 of the liquid circulation pipe 1, and the suction port 11 is configured to be maintained near the liquid surface of the coolant in the storage tank TN2. The discharge port 12 is open to the atmosphere vertically downward, and the liquid to be treated discharged from the discharge port 12 is configured to enter the filter 41 after moving a predetermined distance in the air. Further, a pump 13 for generating a suction force for sucking the liquid to be treated from the suction port 11 is provided in the middle of the liquid circulation pipe 1. This pump 13 is, for example, a diaphragm pump, and a predetermined amount of air is mixed into the sucked liquid to be treated.

[0038] In addition, a ventilation pipe AL is further provided, the tip side of which is connected between the discharge side of the pump 13 and the discharge port 12 of the liquid circulation pipe 1, and the base end side of which is connected to a portion of the storage tank TN2 where there is an upper air layer that the coolant cannot reach. When the pump 13 suddenly stops, for example, air flows into the discharge side of the pump 13 through the ventilation pipe AL. After that, air flows into the space between the discharge side of the pump 13 and the discharge port 12 of the liquid circulation pipe 1, and the coolant in the storage tank TN2 does not flow out from the lower discharge port 12 due to siphon action. In addition, a manually operable on-off valve V is provided between the pump 13 and the discharge port 12 in the liquid circulation pipe 1.

[0039] With reference to FIGS. 3 to 5, the configuration on the downstream side of the discharge port 12 of the liquid distribution pipe 1 will be described in further detail. The liquid to be treated discharged from the discharge port 12 moves in the air and flows into the inside through the inlet opening to the upper side of the recovery container 4. The recovery container 4 has a substantially box shape with an open upper side 42, and a filter 41 formed of a metal mesh is provided on the bottom surface side thereof. Further, a cylindrical wall 43 extends from the lower peripheral side of the filter 41 toward the separation tank 5. Solid components such as floating sludge in the liquid to be treated flowing into the filter 41 are filtered by the filter 41, and floating oil and coolant, which are liquid components, flow into the separation tank along the cylindrical wall 43. Here, the tip of the cylindrical wall 43 is configured to be immersed near the liquid level of the liquid to be treated in a state where a specified amount of the liquid to be treated capable of separating the floating oil and the coolant is stored in the separation tank 5. Further, in a state where the maintenance hatch of the coolant tank 100 is opened, the operator can visually recognize the flow of the liquid to be treated flowing out into the air from the discharge port 12, and can also visually recognize the state of the filter 41 exposed to the air from the opening of the upper part 42 of the recovery container 4. For example, by closing the valve V and temporarily stopping the flow of the liquid to be treated, the filter 41 can also be in a state of not being exposed to the suspended liquid, so that it is easy to evaluate the clogging state of the filter 41. Therefore, before the function of the filter 41 is not sufficiently exerted, the recovery container 4 can be removed from the separation tank 5, and maintenance such as removing and discarding the solid components on the filter 41 can be appropriately performed.

[0040] The separation tank 5 includes a storage section 5T in which the liquid to be treated that has passed through the filter 41 and from which solid components such as floating sludge have been removed is stored, a first discharge section 51 through which the coolant that separates downward due to the difference in specific gravity in the storage section 5T is discharged to the outside of the separation tank 5, a second discharge section 52 through which the floating oil that separates upward due to the difference in specific gravity in the storage section 5T is discharged to the outside of the separation tank 5, and a support section 53 that supports the recovery container 4. The first discharge section 51 and the second discharge section 52 are provided separately on the left and right of the storage section 5T.

[0041] The first discharge part 51 includes a first inflow opening 511 formed in a rectangular shape extending horizontally in the main body partition wall 5W forming the storage part 5T, a buffer part 513 where the coolant flowing in from the first inflow opening 511 stays, and a first discharge port 512 formed in the outer partition wall BW forming the buffer part 513. The first discharge port 512 is provided on the outside thereof and is defined in shape by a socket for connecting a pipe for returning the coolant into the machine. In this embodiment, the opening shape is generally circular, and in a state where the liquid level is low, the flow path area is small. The flow path cross-sectional area of the first inflow opening 511 is configured to be larger than the flow path cross-sectional area of the first discharge port 512. Therefore, even when the flow rate of the coolant flowing in increases, compared with the case where the coolant directly flows into the opening formed by the socket, the liquid level does not increase rapidly and can be increased or decreased proportionally.

[0042] The second discharge part 52 includes a second inflow opening 521 which is a slit formed in the main body partition wall 5W forming the storage part 5T. The horizontal length of the second inflow opening 521 is shorter than that of the first inflow opening 511, and the lower end of the second inflow opening 521 determining the discharge liquid level of the floating oil is set higher than the lower end of the first inflow opening 511 determining the discharge liquid level of the coolant. In this embodiment, since the first inflow opening 511 is formed in a rectangular shape with a larger flow path cross-sectional area than the socket, even when the flow rate of the liquid to be treated and its variation are large, the liquid level of the liquid to be treated in the storage part 5T is less likely to increase or decrease rapidly. For this reason, the margin of the gap between the coolant discharge liquid level and the floating oil discharge liquid level can be set small, so that the time required until the floating oil is discharged from the second discharge part 52 to the oil receiver 6 can be made shorter than before. Therefore, it is possible to reduce the possibility of misunderstanding that the time taken until the floating oil is discharged to the oil receiver 6 is long and there may be some failure or the like.

[0043] Other embodiments will be described. The vertical storage tank may be omitted, and the coolant may be pumped from the recovery tank to each discharge mechanism. Further, the oil separation mechanism according to the present invention may be configured to recover the floating oil from a flat recovery tank. Also, various pumps with known operating principles may be used. The filter may be other than a metal mesh, such as a perforated plate or a non-woven fabric mesh. In short, anything that can filter out solid components may be used. The liquid to be treated discharged from the discharge port does not necessarily flow directly into the filter. For example, it may be applied to the wall surface of the recovery container and then flow into the filter along the wall surface.

[0044] In addition, various modifications and combinations of parts of each embodiment may be made as long as they do not contravene the spirit of the present invention.

Description of Reference Numerals

[0045] 200 Machine tool, 100 Coolant tank, 1 Liquid flow distribution pipe, 11 Suction port, 12 Discharge port, 41 Filter, 5 Separation tank, 51 First discharge part, 52 Second discharge part, 5T Storage part

Claims

1. A storage tank for storing coolant that has passed through a processing area where a workpiece is processed, a liquid flow distribution pipe having a suction port for sucking a liquid to be treated including floating oil, solid components, and coolant from the liquid surface or near the liquid surface of the coolant in the storage tank, and a discharge port through which the liquid to be treated is discharged, a filter for filtering solid components from the liquid to be treated discharged from the discharge port of the liquid flow distribution pipe, a recovery container provided with the filter on the lower side and having an opening through which the liquid to be treated discharged from the discharge port of the liquid flow distribution pipe flows into the upper side, a separation tank for separating the liquid to be treated that has passed through the filter into floating oil and coolant, and the discharge port of the liquid flow distribution pipe is open to the atmosphere, and the filter is provided at a distance outside the discharge port, the recovery container is detachably provided with respect to the separation tank, and a cylindrical wall for guiding the liquid to be treated passing through the filter to the separation tank side is formed on the outlet side of the filter. A coolant tank.

2. The separation tank is a storage section for storing the liquid to be treated that has passed through the filter, a first discharge section through which the coolant separated in the storage section flows out to the outside, a second discharge section through which the floating oil separated in the storage section flows out to the outside, and the first discharge section is formed so as to extend horizontally with respect to the main body partition wall forming the storage section, and has a first inflow opening through which coolant flows in, a buffer section in which the coolant flowing in from the first inflow opening stays, The coolant tank according to claim 1, further comprising a first discharge port formed with respect to an outer partition wall forming the buffer section outside the main body partition wall and through which coolant is discharged to the outside.

3. The coolant tank according to claim 2, wherein a flow path cross-sectional area of the first inflow opening is larger than a flow path cross-sectional area of the first discharge port.

4. The coolant tank according to claim 3, wherein the first discharge port is formed by a socket to which a pipe is connected.

5. The second discharge section is formed so as to extend horizontally with respect to the main body partition wall forming the storage section and includes a second inflow opening through which floating oil flows in, The coolant tank according to claim 3, wherein a lower end of the second inflow opening is set higher than a lower end of the first inflow opening.

6. The separation tank further includes a support portion for supporting the recovery container. The coolant tank according to claim 2, wherein in a state where the recovery container is supported by the support portion, the filter is configured to be disposed closer to the first discharge portion than the second discharge portion.

7. a pump provided in the middle of the liquid flow pipe, The coolant tank according to claim 1, further comprising a ventilation pipe connecting between the discharge side of the pump in the liquid flow pipe and the upper air layer in the storage tank.

8. The coolant tank according to claim 7, further comprising an on-off valve provided between the pump and the discharge port with respect to the liquid flow pipe.

9. A coolant tank according to any one of claims 1 to 8, a machine tool comprising a splash guard in which the processing area is formed inside.

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