JP4375048B2 - Machine Tools - Google Patents

Description

  The present invention relates to a machine tool provided with a coolant supply means.

In a machine tool equipped with a coolant supply means for supplying coolant for cooling the tool, when the tool holder is mounted on the tool holder mounting portion of the spindle, the coolant supply port portion of the spindle-side coolant channel of the spindle is has a configuration Engineering tool side coolant channel of the tool holder is connected, coolant supply means is operated in this state, to supply coolant to the engineering tool side coolant channel from the spindle side coolant channel, the tool Coolant is supplied to a tool such as a drill attached to the holder. This coolant is recovered and fine cutting waste is removed and used again. In this case, the supply pressure of the coolant is set to be quite high so that good supply is achieved.

In such a machine tool, the connection part between the spindle side coolant channel and the tool holder side channel is liquid-tightly pressed by packing or the like, but the coolant supply pressure is high or the packing hardens over time. Otherwise, liquid leakage may occur.
When such a liquid leak occurs, a high pressure of the coolant is applied to the inside of the main shaft, which may affect the seals and bearings of each part.

  In consideration of this, conventionally, the main shaft is provided with a coolant retraction passage in which one end opening communicates with a space portion where the coolant supply port portion of the main shaft side coolant passage faces and the other end opening communicates with the outside of the main shaft. Even if leaks from the connection between the spindle side coolant flow path and the tool holder side flow path, the coolant is configured to flow out through the coolant escape passage, thereby preventing an increase in internal pressure inside the spindle. .

However, since the coolant itself is likely to separate and harden, and there is a possibility that fine cutting scraps are included, the coolant adheres in a solid state to the escape passage itself, and this attachment causes the passage to become There is also a risk of narrowing or clogging.
Assuming that the coolant leaking around the connecting portion between the spindle-side coolant passage and the tool holder-side passage is discharged outside the spindle, an air supply passage communicating with the spindle around the connecting portion, and There is a configuration in which an air discharge path is formed and the coolant leaking around the connection portion is discharged by air pressure when the coolant is supplied (for example, Patent Document 1). In this case, there is no problem when the amount of coolant leakage is small. However, if the amount of coolant leakage increases, high-pressure coolant may flow backward to the air supply passage side (air pump side), which may adversely affect the air pump or the like. Considering this, a considerably high-pressure air supply device is required. However, if high-pressure air is to be obtained, the device becomes considerably large. Further, in this case, there is a possibility that coolant may remain on the air discharge path.
Japanese Patent Laid-Open No. 5-25801

As described above, the configuration disclosed in Patent Document 1 requires a large air supply device, which increases the size of the machine tool. Moreover, there is a possibility that coolant may remain attached to the air discharge path.
In addition, if a coolant retreat passage is simply provided, it is difficult to remove deposits attached to the coolant retraction passage.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a machine tool that can reliably remove deposits in the coolant escape passage without increasing the overall size.

The invention of claim 1 has a tool holder mounting portion that opens at a lower portion to which a tool holder is mounted , has a space portion that communicates with the upper portion of the tool holder mounting portion , and further communicates with the upper portion of the space portion. A spindle having a coolant supply port connected to a tool-side coolant channel provided in the tool holder;
Coolant supply means for supplying coolant to the coolant supply port;
Formed in the main shaft, and the coolant evacuation passage having one end opening communicates with and the other end opening spindle external communication before Symbol space,
Bei example and the coolant supply port of the coolant evacuation passage communicated to channel switching means to one end opening of
The flow path switching means is detachably mounted on the tool holder mounting portion of the spindle, has the same outer shape as the tool holder, has the same outer shape as the pull stud included in the tool holder, and is placed in the space portion when mounted. Consists of a holder-like member having a pull stud-like portion located,
In this holder-like member, one end opening communicates with the coolant supply port portion, and the other end opening faces the one end opening of the coolant retracting passage through the space portion to the pull stud-like portion located in the space portion. It is characterized by forming a communicating path .

  According to this, when the coolant supply port portion of the main shaft is communicated with one end opening of the coolant retracting passage by the flow path switching means, the coolant supplied from the coolant supplying means passes through the coolant retracting passage. Can be cleaned with coolant. In this case, since the coolant retracting passage can be cleaned using the existing coolant supply means, the machine tool is not increased in size. Moreover, since the coolant supply means itself has a higher pressure than the air supply device, the cleaning effect is also improved. In general, it is possible to reliably remove the deposits in the coolant retracting passage without increasing the overall size, and it is possible to reliably eliminate the narrowing and clogging of the coolant retracting passage.

Further, the holder-like member constituting the flow path switching means can be attached to and detached from the main shaft. According to this, the flow path switching means can be detached from the main shaft when the coolant retracting passage is not required to be cleaned.
Further, the flow path shifting unit, characterized in that forms a tool holder and the same external shape and a holder member to be attached to the tool holder mounting portion of the main shaft. According to this, the flow path switching means can be handled in the same manner as the tool holder, and for example, it can be used in the required time by attaching it to the tool magazine in the same manner as other tool holders. It is also possible to use it for channel switching by mounting it on the holder mounting part.

Furthermore, the flow path switching means made of a holder-like member has a communication passage that communicates the coolant supply port portion with one end opening of the coolant retraction passage. According to this, when the flow path switching means made of a holder-like member is mounted on the spindle tool holder mounting portion, the coolant supply port of the spindle-side coolant flow path and the one end opening of the coolant retracting path are communicated with each other by the communication path. .

The invention of claim 2 is characterized in that the flow path switching means is formed in a tool holder of a tool that does not require coolant . According to this, the tool holder can be used also as the flow path switching means. Thereby, it is not necessary to newly provide a flow path switching means, and cost reduction and increase in the number of parts can be suppressed.
Moreover, the tool holder has a holder main body and a pull stud provided at the tip of the holder, and the communication path is formed in the pull stud. According to this, it is not necessary to newly provide the flow path switching means, and the flow path switching means can also be used as a tool holder by replacing only the pull stud.

According to a third aspect of the present invention, there is provided a judging means for judging the time required for cleaning the main shaft. According to this, it is possible to determine when the main shaft needs to be cleaned, and accordingly, it is possible to execute the cleaning of the coolant escape passage by the flow path switching means at the necessary time.
The invention according to claim 4 is characterized in that the determining means determines that it is time to clean when the coolant supply integrated time reaches a predetermined time. Narrowing or clogging of the coolant retreat passage often occurs when the cumulative coolant supply time exceeds a certain time. Therefore, according to the tenth aspect of the present invention, it is possible to appropriately determine the time required for cleaning.

The invention according to claim 5 is characterized in that the judging means judges that it is time for cleaning when the integrated usage time of the tool reaches a predetermined time. The coolant supply amount is also known from the integrated value of the tool usage time, and as a result, the time of passage narrowing or clogging in the coolant escape passage is known. Therefore, according to the eleventh aspect of the present invention, it is possible to appropriately determine the time required for cleaning.

The invention according to claim 6 is characterized in that when the determining means determines the time when cleaning is necessary, the flow path switching means is automatically mounted on the main shaft and the coolant is supplied. According to this, it is possible to automatically perform from the determination of the cleaning necessary time to the execution of cleaning of the coolant escape passage.
The invention according to claim 7 is provided with a notification means, and when the determination means determines the cleaning necessary time, the notification means causes a notification operation. According to this, the user can know when the cleaning is necessary.

  According to the machine tool of the present invention, the coolant retracting passage can be cleaned using the existing coolant supply means, and the cleaning effect can be improved without increasing the size.

  A first embodiment of the present invention will be described below with reference to FIGS. 1 to 7 by applying the present invention to a machining center. 2 and 3 showing the entire configuration, a housing 2 is provided on the base 1. A column 3 is provided at the rear portion of the base 1 so as to be movable in the X direction (left-right direction) and the Y direction (front-rear direction). The column 3 is provided with a Z-direction slide body 4 so as to be movable in the Z-direction (vertical direction). The Z-direction slide body 4 is provided with a spindle head 5, and the spindle 6 rotates on the spindle head 5. It is provided as possible. Accordingly, the main shaft 6 can move in the X, Y, and Z directions. A tool holder 7 for holding a tool is detachably mounted on the main shaft 6.

  A frame 8 is fixed to the front surface of the Z-direction slide body 4, and a tool magazine 9 is provided on the frame 8. The tool magazine 9 is provided with a plurality of grip arms for holding the tool holder 7 individually. When a tool magazine motor 40 (see FIG. 5) as a drive source is driven, the grip arms are sequentially It is moved to the tool change position. The tool is exchanged by exchanging a tool holder holding the corresponding tool, and although detailed description is omitted, the spindle 6 is moved up and down (moved in the axial direction).

A work table 10 to which a work is attached is provided on the front surface of the base 1, and the work is processed by moving the spindle 6 in the X, Y, and Z directions relative to the work on the work table 10. It is the composition to do.
Now, the configuration of the main shaft 6 will be described with reference to FIG. As shown in FIG. 1, the main shaft 6 is rotatably provided to the main shaft head 5 via a bearing 11. Inside the main shaft 6, a tool holder mounting hole 6 a that is penetrated along the central axis and is positioned at the lower end on the axial end side of the main shaft 6 is formed as a tool holder mounting portion.

  Further, the inside of the main shaft 6 is formed in a hollow shape along the axial direction, and a draw bar 12 is provided in the hollow portion so as to be movable in the axial direction. The draw bar 12 is urged upward by a spring 12a. A collet chuck 13 including a plurality of steel balls 13 a and the like is formed at the front end (lower end) of the draw bar 12. In the collect chuck 13, the draw ball 12 is moved downward against the spring force of the spring 12a, so that the steel ball 13a continues from the lower sliding hole 6b of the main shaft 6 to the upper part of the tool holder mounting hole 6a. When the draw bar 12 is moved upward from the lower position, the steel ball 13a is moved from the space portion 6c to the lower sliding hole when the tool bar 7 is released from chucking with respect to the pull stud 7b. 6b and the pull stud 7b is chucked.

  A coolant passage 12 b is formed in the shaft core portion of the draw bar 12. Further, a coolant nozzle 14 is disposed inside the collect chuck 13, and a coolant passage 14 a communicating with the coolant passage 12 b is formed in the axial center portion of the coolant nozzle 14. These coolant passages 12b and 14a constitute a spindle-side coolant passage 15. The coolant supply port 15 a (the lower end opening of the coolant passage 14 a) of the main shaft side coolant channel 15 faces the space 6 c when the tool holder 7 is detached. The coolant nozzle 14 is urged downward by a spring 14b (in the direction of the tool side coolant passage 17 described later).

In the main shaft 6, for example, two coolant retreat passages 16 are formed symmetrically. The coolant retreat passage 16 has one end opening 16 a communicating with the space 6 c facing the coolant supply port 15 a of the main shaft side coolant passage 15, and the other end opening 16 b communicating with the outside on the lower end side of the main shaft 6. It is formed as follows.
The tool holder 7 includes a holder main body 7a and a pull stud 7b, and coolant passages 7c and 7d are formed in the holder main body 7a and the pull stud 7b, respectively. 17 is configured. A tool (illustrated) such as a drill or a tap is attached to the tool holder 7.

FIG. 1 shows a state in which a flow path switching member 18 as a flow path switching means is attached to the main shaft 6. The flow path switching member 18 has substantially the same outer shape as the tool holder 7, and is composed of a holder-like member that is detachably mounted in the tool holder mounting hole 6 a of the main shaft 6.
The pull stud-like portion 18a that is the upper end portion of the flow path switching member 18 communicates with the coolant supply port portion 15a of the spindle-side coolant flow path 15 and one end opening 16a of the coolant retreat passage 16, for example, T-shape. A communication path 18b having a shape is formed. Since the flow path switching member 18 has the same outer shape as the tool holder 7, it can be attached to the tool magazine 9.

  The other end opening 15b of the main shaft side coolant passage 15 is connected to a coolant pump 19 (see FIG. 5) constituting a part of the coolant supply means. The coolant supply means includes the coolant pump 19, a coolant pressure regulator, a coolant supply pipe, a coolant recovery device, a filter, and the like. This coolant supply means supplies coolant at a pressure of 7 MPa, for example.

  This machine is controlled by the control device 20 shown in FIG. The control device 20 is mainly a computer 24 having a CPU 21, ROM 22, RAM 23 and a bus 24a for connecting them. The computer 24 also functions as a determination unit. An input interface 25 is connected to the bus 24a, and an operating device 26 and an input device 27 are connected. The operation device 26 is used for inputting tool data and the like, and includes a number of keys. The input device 27 receives NC data from the NC data storage medium.

  An output interface 28 is connected to the bus 24a. The output interface 28 is connected to the X-axis direction drive motor 36, the Y-axis direction drive motor 37, and the Z-axis via drive circuits 29 to 34 and a control circuit 35, respectively. An axial drive motor 38, a spindle drive motor 39, a tool magazine motor 40, a coolant pump 19 and a display device 41 are connected. The X axis direction drive motor 36 and the Y axis direction drive motor 37 are motors for driving the column 3 in the X direction and the Y direction, respectively. The Z axis direction drive motor 38 is a motor for driving the Z direction slide body 4. It is a motor for driving in the Z direction. The spindle drive motor 39 is a motor for driving the spindle 6, and the tool magazine motor 40 is a motor for driving a grip arm of the tool magazine 9.

  4 shows a state in which the tool holder 7 holding a tool (not shown) is mounted in the tool holder mounting hole 6a of the spindle 6. Although not shown, it is assumed that the flow path switching member 18 is attached to the tool magazine 9. In this state, the coolant supply port 15 a of the spindle side coolant channel 15 is connected to the tool side coolant channel 17.

  In this state, when the machining of the workpiece is started, the computer 24 of the control device 20 executes the control related to the coolant supply as shown in the flowchart of FIG. First, a predetermined initialization is performed (step S1), and if there is a coolant pump activation command (“YES” in step S2), the coolant pump 19 is activated, and an operating time integration timer for this coolant pump 19 is activated. (Step S3). When the coolant pump 19 is started, the coolant is supplied to the tool from the coolant supply port portion 15a of the main shaft side coolant passage 15. At this time, it is supplied at a pressure of 7 MPa. The operating time integration timer is composed of a soft timer by the computer 24. However, a separate mechanic timer or digital timer may be used.

  Next, the accumulated time by the operating time integrating timer of the coolant pump 19 is read (step S4), and if the accumulated time of the operating time integrating timer does not exceed the set time (cleaning required time) (“NO” in step S5). Then, normal processing is executed (step S6). This normal processing includes editing of a machining program that is the basis of the machine tool, control for machining according to the machining program, and power-off processing.

When there is no coolant pump start command or when a coolant pump stop command is issued (“YES” in step S7), the coolant pump 19 is stopped and the operating time integration timer is stopped (step S8). The process proceeds to step S4.
Here, when the operating time integration timer of the coolant pump 19 exceeds the set time (“YES” in step S5), a cleaning process (step S10) of the coolant retreat passage 16 is executed. The contents of this cleaning process are shown in FIG. 7 shown as a subroutine.

In the cleaning process shown in FIG. 7, the flow path switching member 18 is automatically attached to the main shaft 6 to supply the coolant. First, the flow path switching member 18 is searched (step R1). That is, the magazine number in which the flow path switching member 18 is mounted in the tool magazine 9 is searched. If the coolant pump 19 is being activated at this time (“YES” in step R2), the coolant pump 19 is stopped and the operating time integration timer is stopped (step R3), and then the flow path switching member 18 and the spindle The tool holder 7 attached to 6 is exchanged (step R4). This state is shown in FIG. In this state, the coolant switching port 15 a of the main shaft side coolant channel 15 communicates with the one end opening 16 a of the coolant retracting passage 16 by the channel switching member 18. Specifically, as can be seen from FIG. 1, one end opening of the communication passage 18b communicates with the coolant supply port portion 15a, and the other end opening of the communication passage 18b passes through the space portion 6c. To one end opening 16a.

And the coolant pump 19 is started (step R5). As a result, the high-pressure (7 MPa in this case) coolant passes through the coolant retreat passage 16 via the space 6c. Thereby, the coolant escape passage 16 is reliably cleaned.
When the preset cleaning time has elapsed ("YES" in step R6), the coolant pump 19 is stopped (step R7), and the flow path switching member 18 is returned to the tool magazine 9 (step R8). The accumulated value of the operating time integration timer is cleared (step R9), and this cleaning process is terminated.

  As described above, according to the present embodiment, the flow path switching member 18 that connects the coolant supply port portion 15a of the spindle side coolant flow path 15 to the one end opening 16a of the coolant retracting path 16 is provided. When the main shaft 6 is mounted, the coolant supplied from the coolant pump 19 passes through the coolant retracting passage 16, and the coolant retracting passage 16 can be cleaned with the coolant. In this case, the coolant retracting passage 16 can be cleaned using the existing coolant supply means (coolant pump 19 or the like), so that the size of the machine tool is not increased. Moreover, since the coolant supply means itself supplies the coolant at a high pressure, it is possible to reliably remove the deposits in the coolant retreat passage 16 and improve the cleaning effect. Therefore, the narrowing and clogging of the coolant escape passage 16 can be eliminated.

In addition, since the flow path switching member 18 is detachable from the main shaft 6, the flow path switching member 18 can be detached from the main shaft 6 when the coolant retracting passage 16 is not required to be cleaned.
Furthermore, since the flow path switching member 18 is formed of a holder-like member that has substantially the same outer shape as the tool holder 7 and is mounted in the tool holder mounting hole 6 a of the main shaft 6, the flow path switching member 18 is configured with the tool holder 7. It can be handled similarly. For example, it can be mounted on the tool magazine 9 in the same manner as other tool holders, and can be used when cleaning is required, and can be mounted on the spindle 6 using the tool holder mounting hole 6a.

  Further, according to the present embodiment, the flow path switching member 18 made of a holder-like member has a communication path 18b that communicates the coolant supply port 15a and the one end opening 16a of the coolant retraction path 16 inside. Thus, when the flow path switching member 18 formed of a holder-like member is mounted in the tool holder mounting hole 6a of the main shaft 6, the coolant supply port portion 15a of the main shaft side coolant flow path 15 and the one end opening 16a of the coolant retracting passage 16 are naturally formed. It communicates with the communication path.

Furthermore, according to the present embodiment, since the computer 24 constitutes a determination means for determining the cleaning necessity time for the main shaft 6, the cleaning of the coolant retracting passage 16 by the flow path switching member 18 is executed at the necessary time. Can do.
In addition, in this case, since the computer 24 as the determination means determines that the cleaning is necessary time when the cumulative coolant supply time has reached a predetermined time, it is possible to appropriately determine the necessary cleaning time.

Furthermore, when the computer 24 as the determining means determines the cleaning necessary time, it automatically attaches the flow path switching member 18 to the main shaft 6 and supplies the coolant. until execution of the cleaning, it can be done automatically, whereby Ru can contribute greatly to labor savings users.

FIG. 8 shows a second embodiment of the present invention. In the second embodiment, although not shown, the display device 41 in the first embodiment is used as a notification means. When the operation time integration timer of the coolant pump 19 determines a predetermined time (cleaning required time) (step S5), a warning that cleaning is necessary is displayed (notification operation) on the display device 41 (step S20). . According to this, the user can know when the cleaning is necessary. The notification means may be a buzzer, a light emitting element, an audio output device, or the like.

FIG. 9 shows a third embodiment of the present invention . In this embodiment, the flow path switching means 51 is formed in the tool holder 52. That is, the tool holder 52 has a holder main body 52a and a pull stud 52b provided at the tip of the holder body 52a, and a T-shaped communication path 51a constituting the flow path switching means 51 is formed in the pull stud 52b. .
According to the third embodiment, since the flow path switching means 51 is formed on the tool holder 52, the tool holder 52 can be used also as the flow path switching means 51. Thereby, it is not necessary to newly provide the flow path switching means 51, and the cost reduction and the increase in the number of parts can be suppressed. In this case, the tool holder 52 is preferably a tool holder for a tool that does not require coolant.

Furthermore, according to the third embodiment, the pull stud 52b can also be used as the flow path switching means 51. Thus, it is not necessary provided the flow path shifting unit newly, moreover, in the exchange of only the pull stud 52 b, Ru can also serves as the flow path switching means and the tool holder 52.

In the first embodiment, the operating time of the coolant pump is integrated, and when the integrated time exceeds a predetermined time, it is determined that it is time for cleaning. When the accumulated usage time value reaches a predetermined time, it may be determined that it is time for cleaning. In this case, as shown in FIG. 10 shown as the fourth embodiment of the present invention, the type of tool using the coolant pump is stored in relation to the magazine number of the tool magazine, and the tool of that magazine number is used. The time is also stored as an integrated value. FIG. 10 is a conceptual diagram showing the contents stored in the RAM 23 of the computer 24. In this case, since there are a plurality of tools, it is determined that the cleaning is necessary time when the total value (total integrated value) of the usage time integrated values of the tools exceeds a predetermined time. As a result, the coolant supply amount can be determined, and as a result, the time of passage narrowing or clogging in the coolant escape passage can be determined. When there is only one tool that uses the coolant pump, the use time integrated value of the tool may be used.

  Further, it may be determined that the cleaning is necessary when the number of times of use of the tool to which the coolant is supplied reaches a predetermined number. The coolant supply pressure may be changed between using the tool and cleaning. In this case, the pressure may be slightly reduced during cleaning. Moreover, it is good also as a structure which not the main shaft side but the worktable side moves to a X, Y, Z direction. Further, the main shaft may be configured to be oriented in the horizontal direction and movable in that direction.

  In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

Sectional drawing of the principal-axis part of the flow-path switching member mounting state which shows 1st Example of this invention. Front view of the entire machine tool Side view showing the internal configuration of the entire machine tool Cross-sectional view of the main spindle with the tool holder installed Block diagram showing the controller Flow chart showing control contents related to coolant supply Flow chart showing control contents of cleaning process FIG. 6 equivalent view showing a second embodiment of the present invention. FIG. 1 equivalent view showing a third embodiment of the present invention. A fourth embodiment of the present invention shows a conceptual diagram illustrating the contents stored in the RAM

In the drawings, 5 is a spindle head, 6 is a spindle, 6a is a tool holder mounting hole (tool holder mounting portion), 6c is a space, 7 is a tool holder, 7a is a holder body, 7b is a pull stud, 9 is a tool magazine, 10 is a work table, 12 is a draw bar, 13 is a collet chuck, 14 is a coolant nozzle, 14a is a coolant passage, 15 is a spindle side coolant passage, 15a is a coolant supply port, 16 is a coolant retreat passage, and 17 is a tool side coolant. The flow path, 18 is a flow path switching member (flow path switching means), 18a is a pull stud-like portion, 18b is a communication path, 19 is a coolant pump (coolant supply means), 20 is a control device, and 24 is a computer (determination means). , 41 display device (notification means), the flow path switching unit 51, 52 is a tool holder, 52b denotes a Purusuta' de.

Claims (7)

The tool holder has a tool holder mounting portion that is open at the bottom and to which the tool holder is mounted , and has a space portion that communicates with the upper portion of the tool holder mounting portion , and further communicates with the upper portion of the space portion and is provided with the tool holder. A spindle having a coolant supply port connected to the side coolant channel;
Coolant supply means for supplying coolant to the coolant supply port;
Formed in the main shaft, and the coolant evacuation passage having one end opening communicates with and the other end opening spindle external communication before Symbol space,
Bei example and the coolant supply port of the coolant evacuation passage communicated to channel switching means to one end opening of
The flow path switching means is detachably mounted on the tool holder mounting portion of the spindle, has the same outer shape as the tool holder, has the same outer shape as the pull stud included in the tool holder, and is placed in the space portion when mounted. Consists of a holder-like member having a pull stud-like portion located,
In this holder-like member, one end opening communicates with the coolant supply port portion, and the other end opening faces the one end opening of the coolant retracting passage through the space portion to the pull stud-like portion located in the space portion. A machine tool characterized by forming a communicating path . The tool holder has a tool holder mounting portion that is open at the bottom and to which the tool holder is mounted, and has a space portion that communicates with the upper portion of the tool holder mounting portion, and further communicates with the upper portion of the space portion and is provided with the tool holder. A spindle having a coolant supply port connected to the side coolant channel;
Coolant supply means for supplying coolant to the coolant supply port;
A coolant retraction passage formed in the main shaft, with one end opening communicating with the space and the other end opening communicating with the outside of the main shaft;
A flow path switching means for communicating the coolant supply port portion with one end opening of the coolant escape passage,
The flow path switching means comprises a tool holder for a tool that does not require coolant,
This tool holder has a holder body and a pull stud provided at the tip of the holder body,
One end opening communicates with the coolant supply port portion and the other end opening faces the one end opening of the coolant retracting passage through the space portion with the pull stud located in the space portion in the tool holder. A machine tool characterized by forming The machine tool according to claim 1, further comprising a determination unit that determines when the main shaft needs to be cleaned . 4. The machine tool according to claim 3, wherein the determining means determines that it is time for cleaning when the cumulative coolant supply time reaches a predetermined time . 4. The machine tool according to claim 3, wherein the determining means determines that it is time for cleaning when the accumulated usage time of the tool reaches a predetermined time . The machine tool according to any one of claims 3 to 5, wherein when the determining means determines the time for cleaning, the flow path switching means is automatically attached to the main shaft to supply the coolant . The machine tool according to any one of claims 3 to 5, further comprising a notification unit, wherein when the determination unit determines a cleaning-needed time, the notification unit performs a notification operation .

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