CUTTING FLUID CIRCULATION DEVICE

A cutting fluid circulation device includes a tank reservoir, a drum filter, and a pump. The tank reservoir stores cutting fluid discharged from a machine tool. The drum filter is disposed in the tank reservoir. The drum filter performs as a primary filter that filters cutting fluid. The pump pumps up cutting fluid in the tank reservoir. An annular flow channel in which the cutting fluid filtered by the drum filter circulates is formed in the tank reservoir. A part of the cutting fluid pumped up by the pump is fed to the drum filter, used for cleaning the drum filter, and then returned to the annular flow channel, and a part of the remaining cutting fluid is fed to a secondary filter disposed outside the tank reservoir, filtered by the secondary filter, and then returned to the annular flow channel.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Patent Application Number 2022-176668 filed on Nov. 2, 2022, the entirety of which is incorporated by reference.

FIELD OF THE INVENTION

The disclosure relates to a cutting fluid circulation device that stores and filters cutting fluid discharged from a machine tool and resupply the cutting fluid to the machine tool. Note that cutting fluid is also referred to as coolant, and a cutting fluid circulation device is also referred to as a sludgeless tank.

BACKGROUND OF THE INVENTION

There has been known a cutting fluid circulation device as a device attached to a machine tool. The cutting fluid circulation device separates sludge, which is impurities such as chips, from cutting fluid supplied to a work chamber of the machine tool and discharged from the machine tool and supplies the cutting fluid after filtration again to the machine tool for reuse. The cutting fluid circulation device requires cleaning and maintenance by human hands. If the cleaning and maintenance are neglected, the cleaning effect in the work chamber cannot sufficiently be obtained, leading to breakage of the machine in the worst-case scenario.

Therefore, as an example of the cutting fluid circulation device, Japanese Patent No. 5930938 discloses a coolant system in which after coolant discharged from a machine tool to a collecting reservoir is supplied to a primary filtering device with a pump to remove chips and the like, the coolant is stored in a primary reservoir, has fine chips and the like removed by a secondary filtering device, and is returned to the machine tool. The primary reservoir has a bottomed cylindrical shape that is circular in plan view. While the coolant is rotated along the outer periphery of the primary reservoir, the coolant is pumped up by the pump disposed in a central partition member to supply it to the secondary filtering device.

Japanese Patent No. 6196409 discloses a coolant supply device in which coolant discharged from a machine tool is filtered with a drum filter and then returned to a return reservoir. The return reservoir includes first and second coolant reservoirs arranged in parallel with a predetermined space therebetween and a communicating part that allows both coolant reservoirs to communicate with one another. The return reservoir returns the coolant pumped up by a pump disposed in the second coolant reservoir to the first coolant reservoir and assists a flow of the coolant by an agitating nozzle body disposed in each coolant reservoir to suppress deposition and retention of foreign substances.

In the coolant system of Japanese Patent No. 5930938, in addition to the primary and secondary reservoirs, a reservoir is disposed for each filtering device, and pumps are needed at three positions for supplying the coolant from the primary reservoir to the primary filtering device, for supplying the coolant from the secondary reservoir to the secondary filtering device, and for supplying the coolant from the secondary filtering device to the machine tool. Accordingly, the device is complicated, leading to a cost increase.

While the coolant supply device of Japanese Patent No. 6196409 includes one return reservoir, the coolant supply device has a U-shape in plan view, and therefore, the agitating nozzle bodies are required so that the flow does not stagnate. In addition, since five pumps are disposed and each used for cleaning the drum filter, for filtering by another filter device, for forming the flow in the return reservoir, and the like, a cost increase is eventually inevitable.

Therefore, it is an object of the disclosure to provide a cutting fluid circulation device that can ensure cost reduction while maintaining collection performance of sludge with a simple configuration.

SUMMARY OF THE INVENTION

In order to achieve the above-described object, the disclosure provides a cutting fluid circulation device includes a tank reservoir, a drum filter, and a pump. The tank reservoir stores cutting fluid discharged from a machine tool. The drum filter is disposed in the tank reservoir. The drum filter performs as a primary filter that filters cutting fluid. The pump pumps up cutting fluid in the tank reservoir. An annular flow channel in which the cutting fluid filtered by the drum filter circulates is formed in the tank reservoir. A part of the cutting fluid pumped up by the pump is fed to the drum filter, used for cleaning the drum filter, and then returned to the annular flow channel, and a part of the remaining cutting fluid is fed to a secondary filter disposed outside the tank reservoir, filtered by the secondary filter, and then returned to the annular flow channel.

In another aspect of the disclosure, in the above-described configuration, an assist nozzle is disposed in the tank reservoir, and the assist nozzle ejects the cutting fluid to be returned to the annular flow channel in a direction to assist a circulation flow in the annular flow channel.

In another aspect of the disclosure, in the above-described configuration, a straightening vane is disposed in the tank reservoir, the straightening vane straightening the circulation flow in the annular flow channel.

Another aspect of the disclosure, in the above-described configuration, further includes a conveyor installed in the tank reservoir. The conveyor collects sludge from the cutting fluid discharged from the machine tool. The drum filter is installed at a lower portion of the conveyor. The annular flow channel is formed around the conveyor.

Another aspect of the disclosure, in the above-described configuration, further includes a second tank reservoir installed adjacently to the tank reservoir. The cutting fluid filtered by the secondary filter is selectively suppliable via a return flow channel switching unit to any one of a first return flow channel and a second return flow channel. The first return flow channel causes the cutting fluid to return to the annular flow channel. The second return flow channel causes the cutting fluid to return to the second tank reservoir after filtration by a tertiary filter.

With the disclosure, by activating only one pumping-up pump in a simple annular flow channel, cleaning of the drum filter and filtration by the secondary filter can be simultaneously performed. Accordingly, the simple configuration can ensure cost reduction while maintaining collection performance of sludge by the drum filter and the secondary filter.

According to another aspect of the disclosure, the assist nozzle that ejects the cutting fluid to be returned to the annular flow channel in a direction to assist the circulation flow in the annular flow channel is disposed in the tank reservoir. Therefore, in addition to the above effects, the circulation flow in the annular flow channel is assisted, thereby allowing more effective avoidance of retention and accumulation of sludge inside the tank reservoir.

According to another aspect of the disclosure, the straightening vane that straightens the circulation flow in the annular flow channel is disposed in the tank reservoir. Therefore, in addition to the above effects, the smooth circulation flow in the annular flow channel can be maintained, leading to more effective avoidance of retention and accumulation of sludge.

According to another aspect of the disclosure, the conveyor that collects sludge from the cutting fluid discharged from the machine tool is installed in the tank reservoir, the drum filter is installed at the lower portion of the conveyor, and the annular flow channel is formed around the conveyor. Therefore, in addition to the above effects, the annular flow channel centering around the conveyor can easily be formed, allowing the cutting fluid to circulate in the entire tank reservoir.

According to another aspect of the disclosure, the cutting fluid filtered by the secondary filter is selectively suppliable via the return flow channel switching unit to any one of the first return flow channel causing the cutting fluid to return to the annular flow channel and the second return flow channel causing the cutting fluid to return to the second tank reservoir after filtration by the tertiary filter. Therefore, in addition to the above effects, by returning the cutting fluid to the annular flow channel when it is not supplied to a spindle, maintenance of the tertiary filter is required less frequently, leading to prolonged service life of the tertiary filter. On the other hand, by further filtering the cutting fluid by the tertiary filter when the cutting fluid is supplied to the spindle, prolonged service life of a spindle rotary joint unit can be expected.

DETAILED DESCRIPTION OF THE INVENTION

The following describes embodiments of the disclosure based on the drawings.

Embodiment 1 of the disclosure is described below.

FIG.1is a schematic diagram illustrating an exemplary cutting fluid circulation device. A cutting fluid circulation device1includes a first tank reservoir2, a second tank reservoir3, a drum filter4as a primary filter, a pumping-up pump5, a secondary filter6, a pipe switching unit7, a tertiary filter8, and a through pump9.

The first tank reservoir2is a bottomed reservoir having a circumference surrounded by an outer wall10. A conveyor11is installed in the first tank reservoir2. Cutting fluid used in a machine tool and including sludge, such as chips, is discharged to the conveyor11.

The second tank reservoir3, which is installed adjacently to the first tank reservoir2, is a bottomed reservoir having a circumference surrounded by an outer wall12. However, the second tank reservoir3is formed to have an area in plan view smaller than that of the first tank reservoir2. The outer wall12of the second tank reservoir3is formed to be higher than the outer wall10of the first tank reservoir2. Cutting fluid overflowing from the second tank reservoir3flows into the first tank reservoir2.

The drum filter4is installed at a lower portion in the conveyor11. The drum filter4filters cutting fluid at a filter portion on an outer peripheral surface to remove pieces of sludge larger than a predetermined size. The cutting fluid after the filtration is discharged from both ends in an axial direction of the drum filter4into the first tank reservoir2.

The pumping-up pump5is disposed in the first tank reservoir2and connected to a cleaning nozzle, which is not illustrated, in the drum filter4via a first pipe15. Accordingly, the cutting fluid pumped up by the pumping-up pump5is ejected from inside of the drum filter4from the cleaning nozzle to an outer peripheral surface of the drum filter4to clean the drum filter4.

The first pipe15includes a second pipe16branched in its course. The second pipe16is connected to the secondary filter6.

The secondary filter6is a cyclone filter installed outside the first tank reservoir2and the second tank reservoir3. The secondary filter6is connected to the pipe switching unit7via a third pipe17. The cutting fluid from which sludge is removed by the secondary filter6is fed to the pipe switching unit7.

The pipe switching unit7includes a first branch pipe18and a second branch pipe19that are branched into two ways, a first valve20disposed on the first branch pipe18, and a second valve21disposed on the second branch pipe19. The first branch pipe18is connected to the first tank reservoir2via a fourth pipe22. The second branch pipe19is connected to the tertiary filter8via a fifth pipe23.

The tertiary filter8is a bag filter installed outside the first and second tank reservoirs2and3. The cutting fluid filtered by the tertiary filter8is fed into the second tank reservoir3.

The through pump9is installed in the second tank reservoir3. The through pump9supplies the cutting fluid in the second tank reservoir3to a spindle of the machine tool.

FIG.2andFIG.3illustrate details of the first tank reservoir2. Here, the first tank reservoir2has a quadrangular shape in plan view. InFIG.2andFIG.3, front to rear and right to left directions are defined using the right side inFIG.3as the front for convenience. A longitudinal direction of the first tank reservoir2is the front-rear direction.

The first tank reservoir2has respective corner portions in which corner portion straightening vanes30,30inclined in a style of chamfering inner shape corner portions are disposed. The conveyor11is arranged approximately at the center in the first tank reservoir2and in the front-rear direction parallel to the longitudinal direction of the first tank reservoir2. Note that an upper portion of the conveyor11is omitted inFIGS.2and3.

Accordingly, in the first tank reservoir2, an annular flow channel40circulating outside the conveyor11is formed between the outer wall10with the corner portion straightening vanes30; and the conveyor11. The drum filter4is arranged at a rear portion of the conveyor11and includes outlets13,13for filtered cutting fluid disposed at its right and left to allow the drum filter4to communicate with the annular flow channel40.

A straightening vane31is disposed on the right side of the rear portion of the conveyor11and in the first tank reservoir2. The straightening vane31extends to the right side from the rear of the outlet13on the right side, then inclines obliquely toward the right front, and extends forward on the right side of the outlet13. The straightening vane31allows the cutting fluid discharged from the outlet13on the right side to change direction and be biased forward.

The pumping-up pump5is arranged at the front of the straightening vane31and on the right side of the conveyor11. A first pump32is arranged at the front of the pumping-up pump5and on the right side of the conveyor11, and a second pump33is arranged on an opposite side of the first pump32across the conveyor11. The first pump32and the second pump33pump up the cutting fluid in the first tank reservoir2and supply the cutting fluid to a work chamber of the machine tool via pipes that are not illustrated.

Three first to third assist nozzles34to36are disposed in the first tank reservoir2. The first assist nozzle34and the second assist nozzle35are connected to two respective sixth pipes24,24, only one of which is illustrated inFIG.1, branched from the first pipe15. The third assist nozzle36is connected to the fourth pipe22. The first assist nozzle34is arranged on the left side of the flow channel on the rear side of the conveyor11and ejects the cutting fluid toward the right side. The second assist nozzle35is arranged on the right side of the flow channel on the front side of the conveyor11and ejects the cutting fluid toward the left side. The third assist nozzle36is arranged approximately at the center of the flow channel on the left side of the conveyor11and ejects the cutting fluid toward the rear side.

In the cutting fluid circulation device1configured as described above, the cutting fluid collected from the machine tool by the conveyor11passes through the drum filter4to be filtered and then is discharged to the annular flow channel40from the right and left outlets13,13. Since the straightening vane31is disposed on the right side of the drum filter4, the cutting fluid discharged from the outlet13on the right side is biased forward by the straightening vane31. Accordingly, as illustrated by solid arrows inFIGS.2and3, a circulation flow, that is, swirl flow, that allows the cutting fluid to flow counterclockwise in the annular flow channel40is generated in the first tank reservoir2.

Then, when the pumping-up pump5is activated, the cutting fluid in the annular flow channel40is pumped up and supplied to the first pipe15and the second pipe16.

The cutting fluid flowing through the first pipe15is ejected inside the drum filter4from the cleaning nozzle to clean the drum filter4and then returned to the annular flow channel40. Meanwhile, a part of the cutting fluid branched to each sixth pipe24is ejected in a flow direction in the annular flow channel40from the first and second assist nozzles34and35. Accordingly, the flow in the annular flow channel40is assisted.

The cutting fluid flowing through the second pipe16is filtered by the secondary filter6and fed to the third pipe17. At this time, when the cutting fluid is not ejected from a tool mounted to the spindle in the machine tool, the first valve20is turned ON, that is, the valve is opened, and the second valve21is turned OFF, that is, the valve is closed, in the pipe switching unit7. Accordingly, the cutting fluid supplied from the third pipe17passes through the first branch pipe18, travels through the fourth pipe22, and is returned from the third assist nozzle36to the annular flow channel40. The cutting fluid ejected from the third assist nozzle36biases the flow at a left portion of the annular flow channel40to the rear side. Accordingly, the circulation flow in the annular flow channel40is assisted.

By thus activating the pumping-up pump5, the cutting fluid is fed to each of the drum filter4and the secondary filter6to simultaneously perform cleaning of the drum filter4and filtration by the secondary filter6, and the circulation flow in the annular flow channel40is maintained. Accordingly, the flow in one direction can be formed while keeping a flow rate at a certain level or more, allowing avoidance of retention and accumulation of sludge inside the first tank reservoir2.

When machining is performed with the machine tool, the first and second pumps32and33are activated to pump up the cutting fluid in the first tank reservoir2and supply the cutting fluid into the work chamber. At this time, when the cutting fluid is ejected from the tool mounted to the spindle in the machine tool, the first valve20is turned OFF, that is, the valve is closed, and the second valve21is turned ON, that is, the valve is opened, in the pipe switching unit7. Accordingly, the cutting fluid supplied from the third pipe17passes through the second branch pipe19, travels through the fifth pipe23, and is fed to the tertiary filter8. The cutting fluid further filtered by the tertiary filter8is discharged into the second tank reservoir3and pumped up by the through pump9to be fed to the spindle.

Thus, the cutting fluid circulation device1of Embodiment 1 described above includes the first tank reservoir2as one example of a tank reservoir, the drum filter4, and the pumping-up pump5as one example of a pump. The first tank reservoir2stores cutting fluid discharged from a machine tool. The drum filter4is disposed in the first tank reservoir2and filters the cutting fluid. The pumping-up pump5pumps up the cutting fluid in the first tank reservoir2. In the first tank reservoir2, the annular flow channel40in which the cutting fluid filtered by the drum filter4circulates is formed.

Then, a part of the cutting fluid pumped up from the pumping-up pump5is fed to the drum filter4, used for cleaning the drum filter4, and then returned to the annular flow channel40. Meanwhile, a part of the remaining cutting fluid is fed to the secondary filter6disposed outside the first tank reservoir2, filtered by the secondary filter6, and then returned to the annular flow channel40.

With the configuration, by activating only one pumping-up pump5in the simple annular flow channel40, cleaning of the drum filter4and filtration by the secondary filter6can be simultaneously performed. Accordingly, the simple configuration can ensure cost reduction while maintaining collection performance of sludge by the drum filter4and the secondary filter6.

The first to third assist nozzles34to36as one example of an assist nozzle are disposed in the first tank reservoir2. The first to third assist nozzles34to36eject the cutting fluid returned to the annular flow channel40in a direction to assist the circulation flow in the annular flow channel40.

Accordingly, the circulation flow in the annular flow channel40is assisted, allowing more effective avoidance of retention and accumulation of sludge inside the first tank reservoir2.

The corner portion straightening vanes30and the straightening vane31, each of which is one example of a straightening vane, are disposed in the first tank reservoir2. The corner portion straightening vanes30and the straightening vane31straighten the circulation flow in the annular flow channel40.

Accordingly, the smooth circulation flow can be maintained in the annular flow channel40, leading to more effective avoidance of retention and accumulation of sludge.

In the first tank reservoir2, the conveyor11that collects sludge from the cutting fluid discharged from the machine tool is installed, the drum filter4is installed at the lower portion of the conveyor11, and the annular flow channel40is formed around the conveyor11.

Accordingly, the annular flow channel40centering around the conveyor11can be easily formed, allowing the cutting fluid to circulate in the entire first tank reservoir2.

The second tank reservoir3as one example of a second tank reservoir is installed adjacently to the first tank reservoir2. The cutting fluid filtered by the secondary filter6is selectively suppliable via the pipe switching unit7as one example of a return flow channel switching unit to any one of the fourth pipe22as one example of a first return flow channel and the fifth pipe23as one example of a second return flow channel. The fourth pipe22causes the cutting fluid to return to the annular flow channel40. The fifth pipe23causes the cutting fluid to return to the second tank reservoir3after filtration by the tertiary filter8.

Accordingly, by returning the cutting fluid from the fourth pipe22to the annular flow channel40when it is not supplied to a spindle, maintenance of the tertiary filter8is required less frequently, leading to prolonged service life of the tertiary filter8. On the other hand, by further filtering the cutting fluid by the tertiary filter8when the cutting fluid is supplied to the spindle, prolonged service life of a spindle rotary joint unit can be expected.

In Embodiment 1, the position of the pumping-up pump can be changed as necessary. The number and positions of the pumps other than the pumping-up pump can also be changed as necessary.

The number and positions of the assist nozzles and the pipes connected to the assist nozzles can also be changed as necessary. A plurality of assist nozzles may be arranged alongside of one another in a width direction of the flow channel. However, the assist nozzles may be omitted as long as the circulation flow in the annular flow channel is possible.

The shape in plan view of the first tank reservoir may also be changed as necessary. The shape in plan view may be a rectangular shape with the right-left direction being longitudinal instead of the front-rear direction or may be a square shape, polygonal shape, circular shape, or the like.

The straightening vane may be disposed at the outlet on the left side of the primary filter instead of the outlet on the right side or may be disposed at both left and right sides. The shape and position of the straightening vane itself can be changed as necessary.

The following describes other Embodiments 2 and 3 of the first tank reservoir based onFIG.4toFIG.7. However, the same parts as those of Embodiment 1 are denoted by the same reference numerals, and overlapped description will be omitted. In Embodiments 2 and 3, front to rear and right to left directions are defined using the right side inFIG.5andFIG.7as the front for convenience.

Embodiment 2 of the disclosure is described below.

A first tank reservoir2A of a cutting fluid circulation device1A illustrated inFIG.4andFIG.5has a vertically elongate rectangular shape having a length in the front-rear direction longer than the length in the right-left direction, and the conveyor11is disposed on the rear side of the first tank reservoir2A. A rear side flow channel41extending in the right-left direction is formed on the rear side of the conveyor11. A right side flow channel42communicated with a right end of the rear side flow channel41and extending in the front-rear direction is formed on the right side of the conveyor11. The annular flow channel40in a vertically elongate rectangular shape in plan view is formed on the front side of the conveyor11and in the first tank reservoir2A. The right side flow channel42is joined to the annular flow channel40.

In the first tank reservoir2A, the corner portion straightening vanes30,30are disposed at the front and rear on the left side of the annular flow channel40. The drum filter4includes the outlets13,13that allow the drum filter4to communicate with the rear side flow channel41and the annular flow channel40and discharge filtered cutting fluid. A right side straightening vane50is disposed on the rear side of the annular flow channel40. The right side straightening vane50extends forward in a straight line from between the right side flow channel42and the outlet13on the front side of the drum filter4.

An inner side straightening vane51is disposed at the center of the annular flow channel40. The inner side straightening vane51is formed into a vertically elongate rectangular shape in plan view that is one size smaller than the front side of the first tank reservoir2A, and has four corners chamfered. A space surrounded by the inner side straightening vane51is a quasi-clean reservoir52partitioned from the annular flow channel40. However, a communication port53communicated with the annular flow channel40is cut out and formed at a lower end on the right side of a rear portion of the inner side straightening vane51. An extending plate54projecting in an inclined manner from a rear end of the communication port53toward the front right side is foil ted at the chamfering portion on the right side of the rear portion of the inner side straightening vane51adjacent to the communication port53.

The pumping-up pump5is arranged at a corner portion on the right side of a front portion of the annular flow channel40. The first pump32is arranged on the rear side in the quasi-clean reservoir52.

The first assist nozzle34is arranged toward the front side at a communicating portion between the rear side flow channel41and the right side flow channel42. The second assist nozzle35is arranged toward the rear side on the left side of the front portion of the annular flow channel40. The third assist nozzle36is arranged toward the rear side on the front side in the quasi-clean reservoir52.

As illustrated by a two-dot chain line inFIG.5, a temperature regulator55is disposed outside the first tank reservoir2A and at the proximity of the communicating portion between the rear side flow channel41and the right side flow channel42. The temperature regulator55suctions cutting fluid from a suction opening56disposed in the communicating portion to adjust the temperature of the cutting fluid to a predetermined temperature and then delivers the cutting fluid from a delivery opening57. A delivery direction from the delivery opening57is facing forward similarly to the first assist nozzle34.

In the cutting fluid circulation device1A configured as described above, the cuffing fluid collected from the machine tool by the conveyor11passes through the drum filter4to be filtered and then is discharged to the rear side flow channel41and the annular flow channel40from the front and rear outlets13,13. The cutting fluid discharged from the outlet13on the rear side flows to the right side flow channel42and flows facing forward into a right portion of the annular flow channel40by the right side straightening vane50. The cutting fluid discharged from the outlet13on the front side flows facing forward into the right portion of the annular flow channel40by the right side straightening vane50and the extending plate54of the inner side straightening vane51. Accordingly, as illustrated by solid arrows inFIGS.4and5, a circulation flow that allows the cutting fluid to flow counterclockwise in the annular flow channel40is generated in the first tank reservoir2A.

Then, when the pumping-up pump5is activated, the cutting fluid in the annular flow channel40is pumped up and supplied to the first pipe15and the second pipe16.

The cutting fluid flowing through the first pipe15is ejected inside the drum filter4from the cleaning nozzle to clean the drum filter4and then returned to the rear side flow channel41and the annular flow channel40from the front and rear outlets13,13.

Additionally, a part of the cutting fluid branched from the first pipe15to each sixth pipe24is ejected from the first and second assist nozzles34and35into the first tank reservoir2A. The cutting fluid ejected from the first assist nozzle34biases the flow in the right side flow channel42to the front side. The cutting fluid delivered from the delivery opening57of the temperature regulator55also biases the flow in the right side flow channel42to the front side. The cutting fluid ejected from the second assist nozzle35biases the flow at a left portion of the annular flow channel40to the rear side. Accordingly, the circulation flow in the annular flow channel40is assisted.

Meanwhile, the cutting fluid flowing through the second pipe16is further filtered by the secondary filter6and fed to the third pipe17. At this time, when the cutting fluid is not ejected from a tool mounted to a spindle in the machine tool, the first valve20is turned ON, that is, the valve is opened, and the second valve21is turned OFF, that is, the valve is closed, in the pipe switching unit7. Accordingly, the cutting fluid supplied from the third pipe17passes through the first branch pipe18, travels through the fourth pipe22, and is returned from the third assist nozzle36to the first tank reservoir2A. The cutting fluid ejected from the third assist nozzle36biases the cutting fluid in the quasi-clean reservoir52to the rear side. Accordingly, the cutting fluid in the quasi-clean reservoir52flows from the communication port53along the extending plate54into the right portion of the annular flow channel40to assist the circulation flow in the annular flow channel40.

By thus activating the pumping-up pump5, the cutting fluid is fed to each of the drum filter4and the secondary filter6to simultaneously perform cleaning of the drum filter4and filtration by the secondary filter6, and the circulation flow in the annular flow channel40is maintained. Accordingly, the flow in one direction can be formed while keeping a flow rate at a certain level or more, allowing avoidance of retention and accumulation of sludge inside the first tank reservoir2A.

When machining is performed with the machine tool, the first pump32is activated to pump up the cutting fluid in the quasi-clean reservoir52and supply the cutting fluid into a work chamber. At this time, when the cutting fluid is ejected from the tool mounted to the spindle in the machine tool, the first valve20is turned OFF, that is, the valve is closed, and the second valve21is turned ON, that is, the valve is opened, in the pipe switching unit7. Accordingly, the cutting fluid supplied from the third pipe17passes through the second branch pipe19, travels through the fifth pipe23, and is fed to the tertiary filter8. The cutting fluid further filtered by the tertiary filter8is discharged into the second tank reservoir3and pumped up by the through pump9to be fed to the spindle. The cutting fluid overflowing from the second tank reservoir3crosses over the outer wall12and flows into the adjacent first tank reservoir2A.

Thus, the cutting fluid circulation device1A of Embodiment 2 described above also includes the first tank reservoir2A as one example of a tank reservoir, the drum filter4, and the pumping-up pump5as one example of a pump. The first tank reservoir2A stores cutting fluid discharged from a machine tool. The drum filter4is disposed in the first tank reservoir2A and filters the cutting fluid. The pumping-up pump5pumps up the cutting fluid in the first tank reservoir2A. In the first tank reservoir2A, the annular flow channel40in which the cutting fluid filtered by the drum filter4circulates is formed.

Then, a part of the cutting fluid pumped up from the pumping-up pump5is fed to the drum filter4, used for cleaning the drum filter4, and then returned to the annular flow channel40. Meanwhile, the part of the remaining cutting fluid is fed to the secondary filter6disposed outside the first tank reservoir2A, filtered by the secondary filter6, and then returned to the annular flow channel40.

With the configuration, by activating only one pumping-up pump5in the simple annular flow channel40, cleaning of the drum filter4and filtration by the secondary filter6can be simultaneously performed. Accordingly, the simple configuration can ensure cost reduction while maintaining collection performance of sludge by the drum filter4and the secondary filter6, and similar effects to those of the cutting fluid circulation device1of Embodiment 1 can be obtained.

In Embodiment 2, the position of the pumping-up pump can be changed as necessary. The number and positions of the pumps other than the pumping-up pump can also be changed as necessary. For example, a second pump may be arranged in the annular flow channel or the quasi-clean reservoir.

The number and positions of the assist nozzles and the pipes connected to the assist nozzles can also be changed as necessary. A plurality of assist nozzles may be arranged alongside of one another in a width direction of the flow channel. However, the assist nozzles may be omitted as long as the circulation flow in the annular flow channel is possible.

The shape in plan view of the first tank reservoir may also be changed as necessary. The shape in plan view may be a rectangular shape with the right-left direction being longitudinal instead of the front-rear direction. The shape in plan view of the quasi-clean reservoir can also be changed to fit the shape in plan view of the first tank reservoir. The communication port with the annular flow channel may be provided at a different position from the above embodiment.

The conveyor may be arranged on the front side of the first tank reservoir instead of the rear side.

The shape and position of the right side straightening vane can be changed as necessary. The right side straightening vane may be omitted as long as the circulation flow in the annular flow channel is possible.

Embodiment 3 of the disclosure is described below.

A first tank reservoir2B of a cutting fluid circulation device1B illustrated inFIG.6andFIG.7also has a rectangular shape in plan view, which is long in the front-rear direction, and the conveyor11is arranged to be biased to the rear of the first tank reservoir2B.

A left side straightening vane60and a right side straightening vane61that extend in the front-rear direction are disposed at the front of the conveyor11and inside the outer wall10. The left side straightening vane60inclines in parallel with the corner portion straightening vane30on an inner side of the corner portion straightening vane30on the left side of a front portion of the first tank reservoir2B and is joined to a front side straightening vane62parallel to the outer wall10on the front side of the first tank reservoir2B. The front side straightening vane62has a right end that inclines in parallel with the corner portion straightening vane30on the inner side of the corner portion straightening vane30on the right side of the front portion of the first tank reservoir2B. The left side straightening vane60has a rear end portion joined to a partition plate63in the right-left direction that partitions a boundary with the conveyor11excluding the outlet13on the front side of the drum filter4. An inclined straightening vane64is disposed at a corner portion formed by the partition plate63and the left side straightening vane60.

The right side straightening vane61extends in parallel with the left side straightening vane60. The right side straightening vane61has a front end portion interrupted on a near side with respect to the inclined portion of the front side straightening vane62to form a communication port65between the right side straightening vane61and the front side straightening vane62.

A center plate66extending in the front-rear direction on the front side with respect to the outlet13of the drum filter4is arranged between the left side straightening vane60and the right side straightening vane61. Both front and rear ends of the center plate66are away from both the partition plate63and the front side straightening vane62.

Accordingly, in the first tank reservoir2B, an outside annular flow channel70and an inside annular flow channel71are formed. The outside annular flow channel70circulates around the conveyor11, the left side straightening vane60, the right side straightening vane61, and the front side straightening vane62. The inside annular flow channel71circulates on the inner side of the left side straightening vane60, the right side straightening vane61, and the front side straightening vane62centering around the center plate66. The outside annular flow channel70is communicated with the inside annular flow channel71via the communication port65.

A division straightening vane72that divides a flow channel width into right and left is disposed in the front-rear direction at a left portion of the outside annular flow channel70. The division straightening vane72has a rear end that inclines along the corner portion straightening vane30on the inner side of the corner portion straightening vane30. The division straightening vane72divides the left portion of the outside annular flow channel70into an outer divided flow channel73and an inner divided flow channel74.

The pumping-up pump5is arranged to be biased to the rear in the communication port65. The first pump32is arranged on the rear side of the center plate66in the inside annular flow channel71.

The first assist nozzle34is arranged facing rearward on the front side of the division straightening vane72. The second assist nozzle35is arranged facing rearward on the inner side of the left side straightening vane60in the inside annular flow channel71. Here, the third assist nozzle36is connected to the sixth pipe24and arranged facing forward at a corner portion on the right side of a rear portion of the outside annular flow channel70. A fourth assist nozzle37connected to the fourth pipe22is arranged facing forward on the right side of the center plate66in the inside annular flow channel71.

In the cutting fluid circulation device1B configured as described above, the cutting fluid collected from the machine tool by the conveyor11passes through the drum filter4to be filtered and then flows into the outside annular flow channel70and the inside annular flow channel71from the front and rear outlets13,13.

Then, when the pumping-up pump5is activated, the cutting fluid in the outside annular flow channel70is pumped up and supplied to the first pipe15and the second pipe16. The cutting fluid flowing through the first pipe15is ejected inside the drum filter4from the cleaning nozzle to clean the drum filter4and then returned to the outside annular flow channel70and the inside annular flow channel71from the front and rear outlets13,13.

Additionally, a part of the cutting fluid branched from the first pipe15to each sixth pipe24is ejected from the first to third assist nozzles34to36into the first tank reservoir2B. The cutting fluid ejected from the first assist nozzle34biases the flows in the outer divided flow channel73and the inner divided flow channel74to the rear side.

The cutting fluid ejected from the third assist nozzle36biases the flow at the rear portion of the outside annular flow channel70to the front side. Accordingly, a counterclockwise circulation flow is generated in the outside annular flow channel70.

Meanwhile, in the inside annular flow channel71, the cutting fluid discharged from the outlet13on the front side of the drum filter4along the right side straightening vane61to the front side generates a counterclockwise circulation flow. Since the inside annular flow channel71is communicated with the outside annular flow channel70via the communication port65, a part of the flow at a right portion of the outside annular flow channel70joins up with the inside annular flow channel71from the communication port65, thereby assisting the flow.

In addition, the cutting fluid ejected from the second assist nozzle35biases the flow at a left portion of the inside annular flow channel71to the rear side.

The cutting fluid flowing through the second pipe16is further filtered by the secondary filter6and fed to the third pipe17. At this time, when the cutting fluid is not ejected from a tool mounted to a spindle in the machine tool, the first valve20is turned ON, that is, the valve is opened, and the second valve21is turned OFF, that is, the valve is closed, in the pipe switching unit7. Accordingly, the cutting fluid supplied from the third pipe17passes through the first branch pipe18, travels through the fourth pipe22, and is returned from the fourth assist nozzle37to the first tank reservoir2B. The cutting fluid ejected from the fourth assist nozzle37biases the flow at a right portion of the inside annular flow channel71to the front side. Accordingly, the flow in the inside annular flow channel71is assisted.

By thus activating the pumping-up pump5, the cutting fluid is fed to each of the drum filter4and the secondary filter6to simultaneously perform cleaning of the drum filter4and filtration by the secondary filter6, and the circulation flows in the outside annular flow channel70and the inside annular flow channel71are maintained. Accordingly, the flow in one direction can be formed while keeping a flow rate at a certain level or more, allowing avoidance of retention and accumulation of sludge inside the first tank reservoir2B.

When machining is performed with the machine tool, the first pump32is activated to pump up the cutting fluid in the inside annular flow channel71and supply the cutting fluid into a work chamber. At this time, when the cutting fluid is ejected from the tool mounted to the spindle in the machine tool, the first valve20is turned OFF, that is, the valve is closed, and the second valve21is turned ON, that is, the valve is opened, in the pipe switching unit7. Accordingly, the cutting fluid supplied from the third pipe17passes through the second branch pipe19, travels through the fifth pipe23, and is fed to the tertiary filter8. The cutting fluid further filtered by the tertiary filter8is discharged into the second tank reservoir3and pumped up by the through pump9to be fed to the spindle. The cutting fluid overflowing from the second tank reservoir3crosses over the outer wall12and flows into the adjacent first tank reservoir2B.

Thus, the cutting fluid circulation device1B of Embodiment 3 described above also includes the first tank reservoir2B as one example of a tank reservoir, the drum filter4, and the pumping-up pump5as one example of a pump. The first tank reservoir2B stores cutting fluid discharged from a machine tool. The drum filter4is disposed in the first tank reservoir2B and filters the cutting fluid. The pumping-up pump5pumps up the cutting fluid in the first tank reservoir2B. In the first tank reservoir2B, the outside annular flow channel70as one example of an annular flow channel in which the cutting fluid filtered by the drum filter4circulates is formed.

Then, a part of the cutting fluid pumped up from the pumping-up pump5is fed to the drum filter4, used for cleaning the drum filter4, and then returned to the outside annular flow channel70. Meanwhile, the part of the remaining cutting fluid is fed to the secondary filter6disposed outside the first tank reservoir2B, filtered by the secondary filter6, and then returned to the outside annular flow channel70.

With the configuration, by activating only one pumping-up pump5in the simple outside annular flow channel70, cleaning of the drum filter4and filtration by the secondary filter6can be simultaneously performed. Accordingly, the simple configuration can ensure cost reduction while maintaining collection performance of sludge by the drum filter4and the secondary filter6, and similar effects to those of the cutting fluid circulation device1of Embodiment 1 can be obtained.

In Embodiment 3, the position of the pumping-up pump can be changed as necessary. The number and positions of the pumps other than the pumping-up pump can also be changed as necessary. A second pump may be arranged in the outside annular flow channel or the inside annular flow channel.

The number and positions of the assist nozzles and the pipes connected to the assist nozzles can also be changed as necessary. A plurality of assist nozzles may be arranged in the inner divided flow channel. However, the assist nozzles may be omitted as long as the circulation flow in the annular flow channel is possible.

The shape in plan view of the first tank reservoir may also be changed as necessary. The shape in plan view may be a rectangular shape with the right-left direction being longitudinal instead of the front-rear direction. The shape in plan view may be a square shape, polygonal shape, circular shape, or the like. The communication port between the outside annular flow channel and the inside annular flow channel may be provided at a different position from the above embodiment.

The conveyor may be arranged on the front side of the first tank reservoir instead of the rear side.

The following describes modification examples in common between the respective embodiments.

Filters other than those of the above embodiments can be used for the respective filters. The drum filter is not limited to a type built into a conveyor.

The second tank reservoir can be omitted. In this case, the pipe switching unit and the tertiary filter are also omitted, and the cutting fluid is returned from the third pipe to the first tank reservoir.

The temperature regulator of Embodiment 2 may also be disposed in the first tank reservoirs of Embodiments 1 and 3 to be used for assisting the flow of the cutting fluid. However, the temperature regulator can be omitted.