JP6511802B2 - Machine Tools - Google Patents

Description

  The present invention relates to a machine tool that processes a workpiece with a spindle on which a tool is mounted.

  A machine tool holds a work on a table and processes the work with a tool attached to a spindle (see, for example, Patent Document 1). The plurality of bearings rotatably support the main shaft. In order to maintain high processing accuracy for workpieces, bearings need to have high accuracy. Since the bearing supports the main shaft, the cutting resistance generated at the time of work processing acts via the main shaft. Since the bearing is relatively close to the work, the cutting resistance acting on the bearing is large. Therefore, there is a problem that the accuracy of the bearing decreases in a short time. A way to prevent the problem is to maintain the lubricity of the bearing.

  Patent Document 2 discloses a spacer having an outer ring and an inner ring. A spacer is provided between two axially spaced bearings of the main shaft. An oil passage through which the lubricating oil (lubricating fluid) passes is formed between the outer ring and the inner ring. The oil passage leads to each bearing. A passage communicating the oil supply port and the oil passage is formed in the outer ring. Each bearing is connected to an oil outlet. The lubricating oil passes through the oil inlet and oil passage to reach the bearing and lubricates the bearing. Excess lubricating oil is discharged from the oil outlet.

JP, 2013-252573, A Unexamined-Japanese-Patent No. 4-54313

  The configuration for discharging excess lubricating oil is complex. Another way to lubricate the bearings is to apply grease to the bearings. The grease loses its lubricity over long-term use.

  This invention is made in view of such a situation, and it aims at providing the machine tool which maintains the lubricity of a bearing.

  A machine tool according to the present invention comprises: a spindle for mounting a tool to machine a workpiece; a spindle head for housing the spindle; and rotatably supporting the spindle with respect to the spindle head and in the axial direction of the spindle A plurality of bearings spaced apart from each other, a spacer having an inner ring arranged between the bearings on the outer periphery of the main shaft and rotatable with the main shaft and an outer ring fixed to the main shaft head; In a machine tool provided with a guide path for guiding lubricating oil supplied to the bearing, grease composed of a thickener and a lubricating oil is applied to the bearing, and the bearing or the guide path is provided from the outside of the spindle head And a lubricating oil supply unit for supplying lubricating oil to the thickener of the grease through the communication path.

  In the present invention, the spindle mounts a tool to process a workpiece. The bearings rotatably support the main shaft, are spaced apart in the axial direction of the main shaft, and are coated with grease. The spacer is located on the outer periphery of the main shaft between the bearings, and has an inner ring rotating with the main shaft and an outer ring fixed to the main shaft head. Guideways will be provided in the space. The lubricating oil supply unit supplies the lubricating oil from the outside of the spindle head through the connecting path and the guiding path. The lubricating oil passing through the connecting path and the guiding path leads to a thickener of grease applied to the bearing. The grease can absorb lubricating oil and maintain lubricity.

  In the machine tool according to the present invention, the lubricating oil supply unit includes a lubricating container having a storage chamber for storing the lubricating oil, and the lubricating container has an outlet for discharging the lubricating oil, and the communication with the outlet. And a discharge passage connecting the passages, and a discharge mechanism intermittently discharging the lubricating oil from the discharge passage.

  In the present invention, the discharge mechanism intermittently discharges the lubricating oil from the lubricating container from the discharge passage. When the lubricating oil is constantly supplied, the thickener may flow out of the spindle head together with the lubricating oil, but since the lubricating oil is intermittently supplied, the thickener does not flow out.

  In the machine tool according to the present invention, the lubricating container is provided with an inlet for injecting compressed air of an air source, a communication passage connecting the inlet and the outlet, and an outer diameter smaller than the outlet and the inlet. An air passage having the communication passage and the connection passage connecting the storage chamber, the air passage connected to the air source and the inlet, and the compressed air of the air source leading to the inlet; And a control unit for controlling the solenoid valve, and the discharge mechanism includes the air passage, the solenoid valve, and the control unit.

  In the present invention, the inlet injects the compressed air of the air source. The communication passage has a venturi effect since the communication passage communicates the discharge port and the injection port and the outer diameter is smaller than that of the discharge port and the injection port. The connection passage connects the communication passage and the storage chamber, so that the lubricating fluid in the storage chamber is discharged from the discharge passage as it is mixed with compressed air by the Venturi effect. Since the machine tool supplies misty lubricating oil to the inside of the spindle head, a small amount of lubricating oil can be supplied regularly. Therefore, the machine tool can supply lubricating oil efficiently.

  The machine tool according to the present invention is characterized in that the guide path is formed between the inner ring and the outer ring, and the outer diameter of the inner ring increases from the location facing the connection path toward the bearing side. I assume.

  In the present invention, the guide path is formed between the inner ring and the outer ring, and the outer diameter of the inner ring increases from the location facing the connection path toward the bearings. Therefore, since the inner ring side of the guide path forms an inclined surface from the location facing the communication path toward both bearings, the lubricating fluid adhering to the guide surface moves to each bearing side by the rotation of the main shaft.

  The machine tool according to the present invention is characterized in that an end portion of the spindle head has a bearing retainer for supporting the bearing, and the communication path is provided in the bearing retainer.

  In the present invention, when adding a mechanism for supplying lubricating oil later to a machine tool having no mechanism for supplying lubricating oil, it is not necessary to drill the spindle head to form a communication path. It is only necessary to replace the bearing retainer.

  In the machine tool according to the present invention, the bearing rotatably supports the main shaft, is spaced apart in the axial direction of the main shaft, and is coated with grease. The spacer is located on the outer periphery of the main shaft between the bearings, and has an inner ring rotating with the main shaft and an outer ring fixed to the main shaft head. Guideways will be provided in the space. The lubricating oil supply unit supplies the lubricating oil from the outside of the spindle head through the connecting path and the guiding path. The lubricating oil passing through the connecting path and the guiding path leads to a thickener of grease applied to the bearing. The grease can absorb lubricating oil and maintain lubricity.

It is a perspective view which briefly displays the machine tool concerning an embodiment. It is a front view which briefly displays a machine tool. It is a right side view which briefly displays a machine tool. It is a perspective view of a machine tool which omitted a cover etc. which cover a guide rail. FIG. 2 is a plan view schematically showing the configuration in the vicinity of a main axis. It is sectional drawing and piping schematic which briefly show the structure of the main-axis | shaft vicinity. It is a table | surface which shows the ejection result of lubricating oil. It is sectional drawing and piping schematic which briefly show the structure of main-axis | shaft vicinity of a modification.

  A machine tool according to an embodiment of the present invention will be described below based on the drawings. 1 is a perspective view schematically showing a machine tool according to the embodiment, FIG. 2 is a front view schematically showing the machine tool, FIG. 3 is a right side view schematically showing the machine tool, FIG. FIG. 5 is a plan view schematically showing the configuration in the vicinity of the main spindle.

  In the following description, upper and lower, right and left, and front and back indicated by arrows in the drawings are used. As shown in FIGS. 1 to 4, the machine tool 100 includes a base 10, a Y-direction moving device 20, an X-direction moving device 21, a column 22, a Z-direction moving device 23, a spindle head 25, a workpiece support device 30, and the like. The machine tool 100 supports a work by a work support device 30 and processes the work by a tool 26 mounted on a main shaft 28. The tool 26 is detachably mounted to the lower end portion of the main shaft 28 and can be replaced by a tool changer (not shown).

  The spindle head 25 is movable in the X direction, the Y direction, and the Z direction. Each axis of X, Y and Z is an axis indicating the moving direction of the spindle head 25. When the workpiece is rotated about an axis parallel to the X, Y, and Z axes, the rotational axis of the workpiece is referred to as an A axis, a B axis, and a C axis respectively corresponding to the X, Y, and Z axes. The work rotates about the A axis by the rocking motion of the rocking body 31, and rotates about the C axis by the drive of the C-axis drive unit 32 fixed to the rocking body 31. The workpiece is rotatable about two axes.

  The base 10 includes a gantry 11, a spindle base 13, a pair of work bases 14 and the like. The gantry 11 is a substantially rectangular parallelepiped long structure in the front-rear direction. The spindle base 13 has a substantially rectangular parallelepiped shape that is long in the front-rear direction, and is disposed at a rear portion on the gantry 11. The spindle base 13 has an X-direction moving device 21 and a Y-direction moving device 20. The X direction moving device 21 drives the column 22 in the X direction. The Y-direction moving device 20 drives the column 22 in the Y-direction.

  The pair of work bases 14 are disposed on the left and right of the front portion on the gantry 11. Each work base 14 is provided with a front support 14a and a rear support 14b. Each support base 14a, 14b has a columnar shape, and fixes the workpiece support device 30 on the upper surface. The column 22 has a Z-direction moving device 23 at the front. The Z-direction moving device 23 drives the spindle head 25 in the vertical direction. The spindle head 25 rotatably accommodates a spindle 28 (see FIG. 6) extending in the vertical direction. The spindle 28 is connected to a spindle motor 27 provided at the upper end of the spindle head 25. The main spindle 28 is rotated about the axis by the drive of the main spindle motor 27, and the tool 26 mounted at the lower end of the main spindle 28 is rotated. Therefore, the machine tool 100 can cut the workpiece fixed to the workpiece support device 30.

  FIG. 6 is a cross-sectional view and a piping diagram schematically showing the configuration near the main shaft. As shown in FIG. 6, the machine tool 100 is connectable to an air source 60 that generates compressed air. The air source 60 is connected to the main shaft 28 via the first pipe 61. A first solenoid valve 67 for opening and closing the first pipe 61 is provided in the first pipe 61. The first solenoid valve 67 opens and closes according to the command of the control unit 101. When the first solenoid valve 67 is opened, the machine tool 100 supplies compressed air around the main shaft 28 to prevent foreign matter from entering around the main shaft 28.

  The machine tool 100 comprises a container 73 for storing a coolant for cooling the tool. The upper part of the container 73 is connected to the air source 60 via the second pipe 62. The pressurizing valve 69 is provided in the second pipe 62. The pressurization valve 69 opens at the pressure of air.

  An injection nozzle 72 for injecting the coolant is provided near the lower end of the main shaft 28. The injection nozzle 72 is connected to the container 73 via a flow path 71 through which the coolant flows. The liquid supply valve 70 is provided in the flow path 71. The liquid supply valve 70 opens at the pressure of air.

  The third pipe 63 has one end connected between the air source 60 of the second pipe 62 and the pressurizing valve 69, and the other end connected to the liquid supply valve 70. The second solenoid valve 68 (electromagnetic valve) is provided in the third pipe 63. The fourth pipe 64 has one end connected between the second solenoid valve 68 and the liquid supply valve 70 of the third pipe 63, and the other end connected to the pressurizing valve 69.

  The lubricating container 50 is provided on the left side of the spindle head 25. The fifth pipe 65 connects the lubrication container 50 and the fourth pipe 64.

  The second solenoid valve 68 opens and closes in accordance with a command from the control unit 101. When the second solenoid valve 68 is opened, the compressed air of the air source 60 passes through the second pipe 62 and the third pipe 63 and acts on the liquid supply valve 70, so the liquid supply valve 70 is opened.

  When the second solenoid valve 68 is opened, the compressed air passes through the fourth pipe 64 and the pressurizing valve 69 is opened. Since the pressurizing valve 69 is opened, the compressed air acts on the inside of the container 73, and the coolant stored in the container 73 is discharged to the flow path 71. As described above, since the liquid supply valve 70 is open, the coolant is injected from the injection nozzle 72.

  For example, when replacing the tool, the control unit 101 sprays the coolant from the spray nozzle 72 to clean the tool being replaced. The control unit 101 closes the second solenoid valve 68 and does not inject the coolant from the injection nozzle 72 except when necessary. Therefore, the injection nozzle 72 intermittently injects the coolant.

  When the compressed air flows through the fourth pipe 64, the compressed air passes through the fifth pipe 65 and reaches the lubrication container 50. Since the fifth pipe 65 is connected to the fourth pipe 64, the timing of supplying compressed air to the lubricating container 50 depends on the time of injection of the coolant. Therefore, compressed air is supplied to the lubricating container 50 intermittently.

  A storage chamber 51 for storing lubricating oil (lubricating fluid) is formed inside the lubricating container 50. The upper surface of the storage chamber 51 is in the shape of a cone whose apex is on the upper side. An inlet 52 for injecting compressed air is provided on the left side of the lubricating container 50 and above the reservoir 51. The inlet 52 has a tubular shape extending leftward and rightward in the left portion of the lubrication container 50 and communicates with the storage chamber 51. The connecting pipe 53 is fitted into the left end of the inlet 52. The connecting pipe 53 connects the inlet 52 and the fifth pipe 65.

An outlet 54 for discharging the compressed air and the lubricating oil is provided on the right side surface of the lubricating container 50 above the storage chamber 51. The outlet 54 has a tubular shape extending in the right and left direction in the right portion of the lubricating container 50. The lubrication nozzle 57 (discharge passage) is fitted into the right end of the discharge port 54. The lubricating oil has a kinematic viscosity of 0.4 mm ² / s to 200 mm ² / s. The kinematic viscosity is a value at 40 ° C. based on JIS K2283.

  The right portion of the inlet 52 and the left portion of the outlet 54 communicate with each other via a communication passage 55. The diameter of the communication passage 55 is smaller than the diameters of the inlet 52 and the outlet 54 respectively. In other words, the communication passage 55 squeezes the passage formed between the inlet 52 and the outlet 54. The connection passage 56 connects the communication passage 55 with the top of the storage chamber 51. The diameter of the connection passage 56 is smaller than that of the communication passage 55.

  A plurality of bearings 40 disposed at the upper and lower sides of the spindle head 25 so as to be vertically separated, rotatably supports the spindle 28. As shown in FIG. 6, two bearings 40 are disposed at the top and the bottom, respectively. The rolling elements are provided between the inner and outer rings of the bearing 40. The grease is previously applied around the rolling elements.

  Grease is a thickener comprising metal soap (eg lithium soap, aluminum soap, calcium soap, lithium complex soap, aluminum complex soap, calcium complex soap etc.) or non-soap (eg urea, fine silica, organic bentonite) (Porous material), Base oil (lubricating oil), Additives (for example, various polymers such as structural stabilizers or thickeners, antioxidants, extreme pressure agents, rust inhibitors, corrosion inhibitors, molybdenum disulfide, graphite , Melamine cyanurate, PTFE, boron nitride, fluorinated graphite, and various metal powders).

  Use grease No. 2 to 3 for grease. The consistency is based on JIS K2220. The consistency is a unit representing the hardness of grease, and consistency 2-3 indicates that it is harder than the above-mentioned lubricating oil. Therefore, the flowability of the lubricating oil is higher than the flowability of grease.

  Spacers 41 are disposed between the upper and lower bearings 40 and provided to adjust the preload on the bearings 40 or to adjust the dimensions between the bearings 40. The spacer 41 includes a cylindrical inner ring 42 and an outer ring 43 which are relatively rotatable.

  The main shaft 28 is inserted inside the inner ring 42. The inner rings of the bearings 40 located above and below press the inner ring 42 of the spacer 41 from above and below. The inner ring 42 rotates with the inner ring of the bearing 40.

  The outer rings of the bearings 40 located at the upper and lower positions press the outer ring 43 of the spacer 41 from the upper and lower positions, and are fixed in the spindle head 25. The opening 25a is provided on the left side of the spindle head 25 and at a position where the spacer 41 is opposed. The left side surface of the outer ring 43 of the spacer 41 is exposed from the opening 25a. The outer ring 43 is provided with a communication path 43a penetrating on the left side surface.

  A guide surface 42 a for guiding the lubricating oil is formed on the outer peripheral surface of the inner ring 42 of the spacer 41. The guide surface 42a has an inclined surface. Specifically, as shown in FIG. 6, the outer diameter of the inner ring 42 is smallest at the portion 42b opposed to the connection path 43a, and largest at the portions 42c and 42d axially separated from the portion 42b. The outer diameter of the inner ring 42 increases from the point 42b to the points 42c and 42d.

  When the compressed air flows through the fourth pipe 64, the compressed air also passes through the fifth pipe 65 and reaches the lubrication container 50. The machine tool 100 intermittently supplies compressed air to the lubrication container 50.

  The compressed air passes through the connection pipe 53 (inlet 52), the communication passage 55, and the lubrication nozzle 57 (discharge outlet 54), and is injected between the inner ring 42 and the outer ring 43 of the spacer 41 from the communication passage 43a. The diameter of the communication passage 55 is smaller than the diameters of the inlet 52 and the outlet 54 respectively. The communication passage 55 squeezes the passage formed between the inlet 52 and the outlet 54. Therefore, the pressure in the communication passage 55 is lower than that in the inlet 52 and the outlet 54 due to the Venturi effect. The communication passage 55 sucks up the lubricating oil stored in the storage chamber 51 via the connection passage 56.

  The lubricating nozzle 57 sprays the suctioned lubricating oil together with the compressed air, so that the lubricating oil is in the form of a mist. The mist of lubricating oil adheres to the guide surface 42 a of the inner ring 42. When the inner ring 42 rotates, gravity, centrifugal force and Coriolis force mainly act on the lubricating oil. The lubricating oil moves upward when the centrifugal force is larger than the gravity and the Coriolis force on the upper inclined surface of the guide surface 42a. On the lower side of the guide surface 42a, the lubricating oil moves downward by the action of gravity. When the inner ring 42 rotates, the lubricating oil adhering to the outer peripheral surface of the inner ring 42 moves in the axial direction on the guide surface 42 a and reaches between the inner ring and the outer ring of the bearing 40. A space between the inner ring 42 and the outer ring 43 of the spacer 41 constitutes a guide path 44 for guiding the lubricating oil.

  The lubricating oil reaches, for example, rolling elements positioned between the inner ring and the outer ring of the bearing 40 when the main shaft 28 rotates and the work is processed. The bearings 40 maintain smooth rotation for a long time by supplying the lubricating oil.

  Since the grease is previously applied around the rolling elements, the bearing 40 rotates smoothly in the initial state. The grease loses the base oil (lubricating oil) from the thickener (porous material) of the grease applied around the rolling elements at high speed rotation of the bearing 40 and rotation for a long time. Therefore, the lubricity of grease decreases. The lubricating oil enters the thickener with the above-described lubricating oil supply, and the lubricity of the grease is restored. The grease absorbs lubricating oil and suppresses the generation of excess lubricating oil. Since lubricating oil is more fluid than grease, it realizes smooth supply of lubricating oil to grease.

  The machine tool 100 intermittently supplies lubricating oil to the bearing 40 by intermittently supplying compressed air to the inlet 52. Therefore, the lubricant can be prevented from leaking from the bearing 40. When the lubricating oil is continuously supplied, the lubricating oil leaks from the bearing 40 in a large amount.

  The machine tool 100 can supply the lubricating oil to the bearing 40 simply by adding the fifth pipe 65 and the lubricating container 50 to the existing structure in which the coolant is intermittently blown from the injection nozzle 72 using the air source 60. Therefore, no major design change and no increase in manufacturing costs occur.

  The fifth pipe 65 is connected to the fourth pipe 64, and the fifth pipe 65 is connected to the first pipe 61, and the fifth pipe 65 is provided with a solenoid valve, and the solenoid valve is opened and closed by an appropriate timing to The spacer 41 may be supplied continuously or intermittently. For example, at the time of tool replacement, in order to prevent foreign matter from invading, the machine tool 100 performs air exclusion by continuously supplying air from the first pipe 61 to the main shaft 28. When air is removed, the solenoid valve is opened and closed at an appropriate timing to supply lubricating oil to the spacer 41 continuously or intermittently. The control unit 101, the second pipe 62, the third pipe 63, the second solenoid valve 68, the fifth pipe 65, and the lubrication container 50 correspond to a discharge mechanism. The second pipe 62, the third pipe 63, and the fifth pipe 65 correspond to an air passage.

FIG. 7 is a table showing the results of ejection of the lubricating oil. When the kinematic viscosity (a value in the case of temperature 40 ° C based on JIS K2283) of 0.4mm ² / s~200mm ² / s, the lubricating oil went around efficiently bearing 40 becomes atomized. When the kinematic viscosity exceeds 220 mm ² / s, the lubricating oil is less likely to form a mist. The kinematic viscosity of the lubricating oil is preferably 0.4mm ² / s~200mm ² / s. The higher the kinematic viscosity, the less susceptible to temperature changes, so it is suitable for bearing lubrication. However, when the kinematic viscosity is high, the lubricating oil is easy to flow, so it needs to be replenished constantly. Thus kinematic viscosity is most preferably 5.0mm ² / s~50mm ² / s. The lubricating oil may be a base oil used for grease. The lubricating oil is an example of a lubricating fluid. The lubricating oil may partially contain a liquid other than oil (eg, acetone or water). Further, instead of the lubricating oil, a liquid other than the oil may be used as the lubricating liquid. The operator may directly pour the lubricating oil contained in the container into the communication path 43a.

(Modification)
FIG. 8 is a cross-sectional view and a piping diagram schematically showing the configuration in the vicinity of the main shaft of the modified example. In the modification, the communication path is provided in the bearing retainer. The same components as those in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted. At the lower end of the spindle head 250, a bearing retainer 251 supporting the outer ring of the bearing 40 is fixed. The bearing presser 251 is provided with a stop hole 252 from the outer periphery toward the axial center of the main shaft 28, and a through hole 253 in communication with the stop hole 252 and obliquely upward from the end of the stop hole 252. One end of the through hole 253 communicates with the bearing 40, and the other end communicates with the stop hole 252. The locking hole 252 forms a female screw inside. The outlet 57 has a tube 254 at one end. The pipe 254 is made of metal with a male screw formed on the outer periphery. The tube 254 is fastened with the female screw of the locking hole 252. The locking hole 252 and the through hole 253 correspond to a communication path.

  The sixth pipe 600 connects the connecting pipe 53 and the air source 60. A third solenoid valve 670 for opening and closing the sixth pipe 600 is provided in the sixth pipe 600. The third solenoid valve 670 opens and closes according to the command of the control unit 500. When the third solenoid valve 670 is opened, the compressed air of the air source 60 passes through the sixth pipe 600 and reaches the lubrication container 50. The controller 500 opens and closes the third solenoid valve 670 at predetermined time intervals. The sixth pipe 600 corresponds to an air passage.

  The spacer 410 differs only in the inner ring 420. The inner ring 420 and the outer ring 43 form a space 440 having a rectangular cross section at the axial center of the main shaft 28. Upper and lower ends of the space portion 440 have gaps 441 respectively communicating with the bearings 40.

  The lubricating oil in the form of mist in the lubricating container 50 reaches the bearing 40 through the pipe 254 and the through hole 252. The sixth pipe 600, the third solenoid valve 670, and the control unit 500 correspond to a discharge mechanism. The discharge mechanism may have a configuration in which the lubricating container 50 is provided with a pump. The controller 500 repeatedly drives and stops the pump at a predetermined cycle.

25, 250 Spindle head 251 Bearing retainer 26 Tool 28 Spindle 40 Bearing 41 Spacer 42 Inner ring 43 Outer ring 43 a Connection path 44, 440 Guide path 50 Lubricant container (lubricating oil supply part)
51 storage chamber 52 inlet 54 exhaust 55 communication passage 56 connection passage 57 lubrication nozzle (discharge passage)
60 air source 61 first piping 62 second piping 63 third piping 64 fourth piping 65 fifth piping 101 control section 253 through hole (communication path)
600 Sixth piping (air passage, discharge mechanism)
670 3rd solenoid valve (solenoid valve, discharge mechanism)
500 control unit (discharge mechanism)

Claims (2)

A spindle for mounting a tool to machine a workpiece; a spindle head for housing the spindle; and a plurality of bearings rotatably supported on the spindle head and spaced from each other in the axial direction of the spindle. A spacer having an inner ring disposed on the outer periphery of the main shaft between the bearings and rotatable with the main shaft and an outer ring fixed to the main shaft head, and lubricating oil provided on the spacer and supplied to the bearings In a machine tool provided with a guiding path,
Grease consisting of thickener and lubricating oil is applied to the bearing,
A communication passage communicating with the bearing or the guide passage from the outside of the spindle head;
A lubricant oil supply unit for supplying a lubricant oil to the grease thickener through the communication path;
The end of the spindle head on which the tool is mounted has a bearing holder for supporting the bearing,
The communication path is provided on the bearing presser ,
The lubricating oil supply unit includes a lubricating container having a storage chamber for storing the lubricating oil,
The lubricating container is
An outlet for discharging the lubricating oil;
A discharge path connecting the discharge port and the communication path;
An inlet for injecting compressed air from an air source;
A communication passage communicating the inlet and the outlet and having an outer diameter smaller than the outlet and the inlet;
A connection passage connecting the communication passage and the storage chamber;
Have
A first air valve which is interposed between the injection nozzle for injecting the coolant to the tool and the container for storing the coolant, and which is opened by air pressure;
A first pipe connecting the air source and the container;
A second air valve interposed in the first pipe and opened by air pressure;
The first air valve, and a second pipe connecting between the air source and the second air valve in the first pipe;
A solenoid valve interposed in the second pipe;
A third pipe connecting between the second air valve and the solenoid valve and the first air valve in the second pipe;
A fourth pipe connecting the inlet and the third pipe;
A control unit that controls the opening and closing of the solenoid valve;
Equipped with
The control unit controls the opening and closing of the solenoid valve to control the opening and closing of the first air valve and the second air valve, and from the discharge passage in synchronization with the injection of the coolant from the injection nozzle. A machine tool characterized in that the lubricating oil is intermittently discharged . The guide path is formed between the inner ring and the outer ring,
The machine tool according to claim 1 , wherein the outer diameter of the inner ring increases from the location facing the connection path toward the bearing.

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