Machine tool, compressed fluid supply device, compressed fluid supply method, and compressed fluid supply program

Abstract

The purpose of the present invention is to provide a machine tool capable of suppressing an increase in environmental load when supplying compressed fluid into a main spindle device after completing machining.　A machine tool 1 comprises: a main spindle device 11 including a main spindle 11a, a housing 11b that accommodates the main spindle 11a, and bearings 11c, 11d that are disposed inside the housing 11b and rotatably support the main spindle 11a; and a compressed fluid supply device 30 for supplying compressed fluid into the main spindle device 11. After machining using the main spindle device 11 is completed, the compressed fluid supply device 30 executes initial supply processing for supplying the compressed fluid into the main spindle device 11 until a predetermined first temperature condition is satisfied, when the first temperature condition is satisfied, the compressed fluid supply device 30 executes first reduction supply processing for supplying the compressed fluid into the main spindle device 11 while reducing the amount of the compressed fluid supplied per unit time, and when a predetermined completion temperature condition is satisfied, the compressed fluid supply device 30 executes supply completion processing for completing the supply of the compressed fluid.

Description

Machine tool, compressed fluid supply device, compressed fluid supply method, and compressed fluid supply program

[0001] This disclosure relates to a machine tool, a compressed fluid supply device, a compressed fluid supply method, and a compressed fluid supply program.

[0002] In machine tools, there is a known technique for supplying compressed fluid, such as compressed air, into the spindle while the internal temperature of the spindle is higher than the external temperature of the spindle after the machining process is completed (see, for example, Patent Document 1). In the technique described in Patent Document 1, the control device determines the amount and duration of compressed fluid to be supplied into the spindle based on the difference between the internal and external temperatures of the spindle, and supplies the compressed fluid into the spindle at the determined amount for the determined duration.

[0003] The technology described in Patent Document 1 prevents foreign matter from entering the spindle by supplying a fixed amount of compressed fluid to the spindle for a determined supply time at a determined supply rate after the machining process is completed. Furthermore, the technology described in Patent Document 1 can achieve energy savings by stopping the power supply to the temperature sensors that detect the internal and external temperatures of the spindle used when determining the supply rate and supply time, after the supply rate and supply time have been determined.

[0004] Patent No. 4938419

[0005] However, the technology described in Patent Document 1 supplies a certain amount of compressed fluid into the spindle after the machining process is completed. Therefore, when the internal temperature of the spindle has decreased, there is a risk of supplying more compressed fluid than necessary into the spindle, thereby increasing the environmental burden.

[0006] This disclosure aims to solve these problems and to provide a machine tool that can suppress the increase in environmental load when compressed fluid is supplied to the inside of the spindle device after the machining process is completed.

[0007] The machine tool according to this disclosure comprises a spindle unit having a spindle, a housing for the spindle, and bearings disposed inside the housing that rotatably support the spindle, and a compressed fluid supply unit that supplies compressed fluid into the spindle unit. The compressed fluid supply unit performs an initial supply process to supply compressed fluid into the spindle unit after machining by the spindle unit is completed, until a predetermined first temperature condition is met. When the first temperature condition is met, it performs a first reduction supply process to supply compressed fluid into the spindle unit by reducing the amount of compressed fluid supplied per unit time. When a predetermined end temperature condition is met, it performs a supply termination process to terminate the supply of compressed fluid.

[0008] Furthermore, in the machine tool according to the present disclosure, in the first reduced supply process, it is preferable that the compressed fluid supply device performs a first supply process in which it supplies compressed fluid at a first supply amount for a first supply time, and after performing the first supply process, it performs a second supply process in which it supplies compressed fluid at a second supply amount greater than the first supply amount for a second supply time.

[0009] Furthermore, in the machine tool according to the present disclosure, it is preferable that the compressed fluid supply device further performs a second reduction supply process in which, when a second temperature condition is further met indicating that the internal temperature of the spindle device is lower than the internal temperature corresponding to the first temperature condition, the amount of compressed fluid supplied per unit time is reduced compared to the first reduction supply process and compressed fluid is supplied to the inside of the spindle device.

[0010] Furthermore, in the machine tool according to this disclosure, if the compressed fluid supply device is performing the first supply process when the second temperature condition is further satisfied, it is preferable that the second supply process be performed after the first supply process is performed.

[0011] Furthermore, in the machine tool according to the present disclosure, in the second reduction supply process, it is preferable that the compressed fluid supply device performs a third supply process in which it supplies compressed fluid at a first supply amount for a third supply time that is longer than the first supply time, and then performs the second supply process after performing the third supply process.

[0012] Furthermore, in the machine tool according to this disclosure, if the compressed fluid supply device is performing the third supply process when the termination temperature condition is further satisfied, it is preferable to perform the second supply process after performing the third supply process.

[0013] Furthermore, in the machine tool according to this disclosure, it is preferable that the compressed fluid supply device sets the first supply amount to zero in the first supply process and the third supply process.

[0014] Furthermore, in the machine tool according to this disclosure, the initial supply process is preferably a continuous supply process in which compressed fluid is continuously supplied at a second supply rate.

[0015] Furthermore, in the machine tool according to this disclosure, the first temperature condition, the second temperature condition, and the final temperature condition are the time elapsed since the spindle stopped rotating, and it is preferable that the time corresponding to the second temperature condition is longer than the time corresponding to the first temperature condition, and the time corresponding to the final temperature condition is longer than the time corresponding to the second temperature condition.

[0016] Furthermore, in the machine tool according to this disclosure, it is preferable that the compressed fluid supply device is positioned on the outside of the direction of extension of the main spindle relative to the bearing and has a nozzle for ejecting compressed fluid.

[0017] Furthermore, in the machine tool according to the present disclosure, the bearing preferably includes a front bearing located at the front of the spindle and a rear bearing located at the rear of the spindle, and the nozzle preferably includes a front nozzle located outward in the direction of extension of the spindle relative to the front bearing and a rear nozzle located outward in the direction of extension of the spindle relative to the front bearing.

[0018] The compressed fluid supply device according to this disclosure is a compressed fluid supply device that supplies compressed fluid to the inside of a spindle device having a spindle, a housing that accommodates the spindle, and bearings disposed inside the housing that rotatably support the spindle, and after machining by the spindle device is completed, it performs an initial supply process to supply compressed fluid to the inside of the spindle device until a predetermined first temperature condition is met, when the first temperature condition is met, it performs a first reduction supply process to supply compressed fluid to the inside of the spindle device by reducing the amount of compressed fluid supplied per unit time, and when a predetermined termination temperature condition is met, it performs a supply termination process to terminate the supply of compressed fluid.

[0019] The compressed fluid supply method according to this disclosure relates to a machine tool having a spindle, a housing for the spindle, a spindle device disposed inside the housing and having bearings that rotatably support the spindle, and a compressed air supply device that supplies compressed fluid to the inside of the spindle device. After machining by the spindle device is completed, an initial supply process is performed to supply compressed fluid to the inside of the spindle device until a predetermined first temperature condition is met. When the first temperature condition is met, a first reduction supply process is performed to supply compressed fluid to the inside of the spindle device by reducing the amount of compressed fluid supplied per unit time. When a predetermined termination temperature condition is met, a supply termination process is performed to terminate the supply of compressed fluid.

[0020] The compressed fluid supply program according to this disclosure is for a machine tool having a spindle, a housing for the spindle, a spindle device disposed inside the housing and having bearings that rotatably support the spindle, and a compressed air supply device that supplies compressed fluid to the inside of the spindle device. The program causes a computer to perform the following processes: after machining by the spindle device is completed, an initial supply process is performed to supply compressed fluid to the inside of the spindle device until a predetermined first temperature condition is met; when the first temperature condition is met, a first reduction supply process is performed to supply compressed fluid to the inside of the spindle device by reducing the amount of compressed fluid supplied per unit time; and when a predetermined termination temperature condition is met, a supply termination process is performed to terminate the supply of compressed fluid.

[0021] The machine tool relating to this disclosure can suppress an increase in environmental load when supplying compressed fluid into the spindle unit after the machining process is completed.

[0022] This is a perspective view of a machine tool according to an embodiment. This is a block diagram of the front spindle unit, rear spindle unit, NC unit and supply unit shown in Figure 1. This is a flowchart of the compressed air supply process performed by the machine tool shown in Figure 1. This is a timing chart of the compressed air supply process shown in Figure 3. (a) is a diagram showing the change in internal temperature of the front spindle unit shown in Figure 1 after the machining process is completed, and (b) is a diagram showing the relationship between the internal temperature of the front spindle unit shown in Figure 1 and the volume of air retained inside the front spindle unit. This is a block diagram of the front spindle unit, rear spindle unit, NC unit and supply unit that a machine tool according to a modified example has. This is a flowchart of the compressed air supply process according to the first modified example. This is a timing chart of the compressed air supply process shown in Figure 7. (a) is a timing chart of the compressed air supply process according to the second modified example, and (b) is a timing chart of the compressed air supply process according to the third modified example. (a) is a timing chart of the compressed air supply process according to the fourth modified example, and (b) is a timing chart of the compressed air supply process according to the fifth modified example. This is a timing chart of the compressed air supply process according to the sixth modified example.

[0023] The machine tool, compressed fluid supply device, compressed fluid supply method, and compressed fluid supply program relating to this disclosure will be described below with reference to the drawings. However, it should be noted that the technical scope of this disclosure is not limited to those embodiments, but extends to the disclosures described in the claims and their equivalents.

[0024] (Configuration and Function of the Machine Tool According to the Embodiment) Figure 1 is a perspective view of the machine tool according to the embodiment, and Figure 2 is a block diagram of the front spindle unit 11, the rear spindle unit 12, the NC unit 20, and the compressed air supply unit 30.

[0025] Machine tool 1 comprises a bed 10, a front spindle unit 11, a rear spindle unit 12, a guide bushing device 13, a tool post 14, a numerical control (NC) device 20, a compressed air supply device 30, and a control device 40. Machine tool 1 processes a workpiece W, which is held by the front spindle unit 11 and the rear spindle unit 12 respectively, using a tool 14a held by the tool post 14. The bed 10 is equipped with the front spindle unit 11, the rear spindle unit 12, the guide bushing device 13, and the tool post 14. The front spindle unit 11 and the rear spindle unit 12 are also simply referred to as spindle units.

[0026] The front spindle unit 11 has a hollow front spindle 11a capable of gripping a cylindrical workpiece W supplied from a material feeder (not shown), and is movable in the Z1 direction by being mounted on a moving mechanism that moves along rails 15. The rear spindle unit 12, similar to the front spindle unit 11, has a hollow rear spindle 12a capable of gripping a workpiece W, and is movable in the Z2 and X2 directions by being mounted on a moving mechanism that moves along rails 16 and 17. The guide bush unit 13 supports the vicinity of the tip of the workpiece W gripped by the front spindle 11a.

[0027] The NC device 20 is electrically connected to control mechanisms such as a moving mechanism and a rotating mechanism that control the operation of the front spindle 11, the rear spindle 12, and the tool post 14. The NC device 20 controls the rotation and movement of the front spindle 11 and the rear spindle 12, as well as the movement of the tool post 14, based on a computer program stored in a memory unit (not shown) of the NC device 20. For example, the NC device 20 controls the rotation and movement of the front spindle 11 and the rear spindle 12, as well as the movement of the tool post 14, based on a workpiece machining program stored in the memory unit, to perform a machining process to machine the workpiece W.

[0028] The front spindle unit 11, also simply called the spindle unit 11, comprises a front spindle 11a, a front housing 11b, a front front bearing 11c, a front rear bearing 11d, and a front motor 11e. The front spindle 11a, front housing 11b, front front bearing 11c, front rear bearing 11d, and front motor 11e are each simply referred to as the spindle 11a, housing 11b, front bearing 11c, rear bearing 11d, and motor 11e, respectively. The front spindle unit 11 rotates the workpiece W held by the front spindle 11a using the front motor 11e when the workpiece W held by the front spindle 11a is machined by a tool 14a held on the tool post 14. A temperature sensor (not shown) for measuring the internal temperature is located near the front spindle unit 11.

[0029] The front spindle 11a grips the workpiece W with a collet chuck (not shown). The front housing 11b is a housing that accommodates the front spindle 11a, the front front bearing 11c, the front rear bearing 11d, and the front motor 11e, and has multiple gaps formed therein that allow internal air to be released to the outside. The front front bearing 11c is a rolling bearing located near the tip of the front spindle 11a, i.e., at the front, and rotatably supports the front spindle 11a. The front rear bearing 11d is a rolling bearing located near the rear end of the front spindle 11a, i.e., at the rear, and rotatably supports the front spindle 11a. The front motor 11e is electrically connected to the NC device 20 and rotates and stops the front spindle 11a based on instructions from the NC device 20.

[0030] The rear spindle unit 12, also simply called the spindle unit 12, comprises a rear spindle 12a, a rear housing 12b, a rear front bearing 12c, a rear rear bearing 12d, and a rear motor 12e. The rear spindle 12a, rear housing 12b, rear front bearing 12c, rear rear bearing 12d, and rear motor 12e are each simply referred to as the spindle 12a, housing 12b, front bearing 12c, rear bearing 12d, and motor 12e, respectively. The rear spindle unit 12 rotates the workpiece W held by the rear spindle 12a using the rear motor 12e when the workpiece W held by the rear spindle 12a is machined by a tool 14a held on the tool post 14.

[0031] The rear spindle 12a grips the workpiece W with a collet chuck (not shown). The rear housing 12b is a housing that accommodates the rear spindle 12a, the rear front bearing 12c, the rear rear bearing 12d, and the rear motor 12e, and has multiple gaps formed therein that allow internal air to be released to the outside. The rear front bearing 12c is a rolling bearing located near the tip of the rear spindle 12a that rotatably supports the rear spindle 12a, and the rear rear bearing 12d is a rolling bearing located near the rear end of the rear spindle 12a that rotatably supports the rear spindle 12a. The rear motor 12e is electrically connected to the NC device 20 and rotates and stops the rear spindle 12a based on instructions from the NC device 20.

[0032] The compressed air supply device 30 includes a compressor 31, a pressure tank 32, a front discharge valve 33, a rear discharge valve 34, a front front nozzle 35, a front rear nozzle 36, a rear front nozzle 37, a rear rear nozzle 38, piping 39, and a control device 40. The compressed air supply device 30 is also called a compressed fluid supply device, and it generates compressed air from the atmosphere and supplies the generated compressed air to the inside of the front spindle device 11 and the rear spindle device 12.

[0033] After the machining of the workpiece W is completed and the front spindle 11a and rear spindle 12a stop rotating, the compressed air supply device 30 performs an initial supply process to supply a predetermined amount of compressed air to the front spindle device 11 and the rear spindle device 12 until a predetermined first temperature condition is met. After the first temperature condition is met, the compressed air supply device 30 performs a first reduction supply process to supply compressed air to the interior of the front spindle device 11 and the rear spindle device 12 by reducing the amount of compressed air supplied per unit time. When a predetermined second temperature condition is further met, the compressed air supply device 30 further performs a second reduction supply process to supply compressed air to the interior of the front spindle device 11 and the rear spindle device 12 by further reducing the amount of compressed air supplied per unit time compared to the first reduction supply process. When a predetermined end temperature condition is met, the compressed air supply device 30 performs a supply termination process to terminate the supply of compressed air.

[0034] The compressor 31 inhales air, compresses the inhaled air to generate compressed air with a predetermined pressure, and discharges the generated compressed air to the pressure tank 32 via piping 39. The pressure tank 32 is a storage tank that stores the compressed air discharged from the compressor 31, and its internal pressure is detected by a pressure sensor 32a. The pressure sensor 32a outputs the detected internal pressure of the pressure tank 32 to the compressor 31. The compressor 31 starts generating compressed air when the internal pressure of the pressure tank 32 reaches a predetermined starting pressure, and stops generating compressed air when the internal pressure of the pressure tank 32 reaches a predetermined ending pressure.

[0035] The front discharge valve 33 and the rear discharge valve 34 are solenoid valves whose opening and closing operations are controlled by the control device 40, and are connected to the pressure tank 32 via piping 39. The front front nozzle 35 is positioned outside the front main shaft 11a in the direction of extension relative to the front front bearing 11c, and the front rear nozzle 36 is positioned outside the front main shaft 11a in the direction of extension relative to the front rear bearing 11d. The front front nozzle 35 and the front rear nozzle 36 are connected to the front discharge valve 33 via piping 39, and when the front discharge valve 33 is open, it discharges compressed air stored in the pressure tank 32.

[0036] The rear front nozzle 37 is positioned on the outside of the rear main shaft 12a in the direction of extension relative to the rear front bearing 12c, and the rear rear nozzle 38 is positioned on the outside of the rear main shaft 12a in the direction of extension relative to the rear rear bearing 12d. The rear front nozzle 37 and the rear rear nozzle 38 are connected to the rear discharge valve 34 via piping 39, and when the rear discharge valve 34 is open, compressed air stored in the pressure tank 32 is ejected.

[0037] The control device 40 is an electronic computer such as a personal computer, having a communication unit 41, a storage unit 42, an operation unit 43, a display unit 44, and a processing unit 45.

[0038] The communication unit 41 has a communication interface circuit for connecting the control device 40 to the NC device 20, the front discharge valve 33, and the rear discharge valve 34 via electrical wiring 46. The communication unit 41 supplies data received from the NC device 20 via electrical wiring 46 to the processing unit 45. The communication unit 41 also transmits data supplied from the processing unit 45 to the NC device 20, the front discharge valve 33, and the rear discharge valve 34 via electrical wiring 46.

[0039] The storage unit 42 includes, for example, at least one of a semiconductor memory device, a magnetic tape device, a magnetic disk device, or an optical disk device. The storage unit 42 stores operating system programs, driver programs, application programs, data, etc., used for processing in the processing unit 45. For example, the storage unit 42 stores a compressed air supply program, etc., which causes the processing unit 45 to execute a compressed air supply process that supplies compressed air to the inside of the front spindle device 11 and the rear spindle device 12. The compressed air supply program may be installed in the storage unit 42 from a computer-readable portable storage medium such as a CD-ROM or DVD-ROM using a known setup program, etc.

[0040] The operation unit 43 can be any device that allows data input, such as a touch panel or keyboard. An operator using the control device 40 can input characters, numbers, symbols, etc., using the operation unit 43. When the operation unit 43 is operated by the operator, it generates a signal corresponding to that operation. The generated signal is then supplied to the processing unit 45 as an instruction from the operator.

[0041] The display unit 44 can be any device capable of displaying video or images, such as a liquid crystal display or an organic EL display. The display unit 44 displays video corresponding to video data supplied from the processing unit 45, or images corresponding to image data. The display unit 44 may also be an output device that prints video, images, or characters onto a display medium such as paper. The display unit 44 may also display a graphical user interface (GUI) for operating the control device 40.

[0042] The processing unit 45 comprises one or more processors and their peripheral circuits. The processing unit 45 comprehensively controls the overall operation of the control device 40 and is, for example, a CPU. The processing unit 45 executes processing based on programs (driver programs, operating system programs, application programs, etc.) stored in the storage unit 42. The processing unit 45 can also execute multiple programs (application programs, etc.) in parallel.

[0043] (Compressed air supply process performed by a machine tool according to the embodiment) Figure 3 is a flowchart of the compressed air supply process performed by the machine tool 1, and Figure 4 is a timing chart of the compressed air supply process shown in Figure 3. In Figure 4, the horizontal axis represents time, and the vertical axis represents the opening degree of the front discharge valve 33. The compressed air supply process shown in Figures 3 and 4 is performed mainly by the control device 40 in cooperation with each element of the machine tool 1, based on a compressed air supply process program stored in the storage unit 42 in advance. The compressed air supply process shown in Figures 3 and 4 includes the process performed in the compressed fluid supply method according to the embodiment. The compressed air supply process shown in Figures 3 and 4 shows the process of supplying compressed air to the inside of the front spindle device 11, but the process of supplying compressed air to the inside of the rear spindle device 12 is performed in the same way as the compressed air supply process shown in Figures 3 and 4. The flowchart shown in Figure 3 shows the process after the start of the machining process.

[0044] Furthermore, the compressed air supply process shown in Figures 3 and 4 is performed after the machining process of processing the workpiece W using the front spindle unit 11 and the tool post 14 is completed. While the machining process is being performed, the front discharge valve 33 is open, and compressed air stored in the pressure tank 32 is ejected from the front front outlet 35 and the front rear outlet 36 via the front discharge valve 33. As compressed air is ejected from the front front outlet 35 and the front rear outlet 36, the internal pressure of the front spindle unit 11 becomes higher than the external pressure, and the inside of the front spindle unit 11 becomes a positive pressure state.

[0045] First, the processing unit 45 determines whether a machining completion signal has been input from the NC device 20 indicating that the machining process of processing the workpiece W using the front spindle device 11 and the tool post 14 has been completed (S101). When the NC device 20 completes the machining process and outputs a machining completion signal to the control device 40, and the machining completion signal is input to the processing unit 45 via the communication unit 41, the processing unit 45 determines that a machining completion signal has been input from the NC device 20 (S101-YES). The processing unit 45 repeats the process shown in S101 until it determines that a machining completion signal has been input from the NC device 20 (S101-YES). While the processing unit 45 repeats the process shown in S101, it continues the machining process and continues the machining supply process, which supplies compressed air to the inside of the front spindle device 11 by ejecting compressed air from the front front nozzle 35 and the front rear nozzle 36. Compressed air is supplied to the inside of the front spindle device 11 by ejecting compressed air. The processing unit 45 maintains a positive pressure state inside the front spindle unit 11 while the machining supply process is ongoing. The machining supply process may also be a continuous supply process that continuously supplies a predetermined amount of compressed air.

[0046] When the processing unit 45 determines that a machining completion signal has been input from the NC device 20 at time t0 (S101-YES), it starts an initial supply process to supply compressed air into the front spindle device 11 from the front front nozzle 35 and the front rear nozzle 36, and starts a timing process to measure the time since the machining process was completed (S102).

[0047] Next, the processing unit 45 performs the first threshold time T after the processing is completed.th1 Determine whether the time has elapsed (S103). The first threshold time T th1 is an example of the first temperature condition indicating the change in the internal temperature of the front spindle device 11 after the machining process is completed, and is determined from an empirical rule, for example, 30 minutes. Note that the temperature inside the front spindle device 11 after the machining process is completed is acquired by a temperature sensor arranged near the front spindle device 11, and the first threshold time T th1 may be determined according to the acquired temperature.

[0048] The processing unit 45 executes the initial supply process until it is determined that the first threshold time T th1 has elapsed after the machining process is completed (S103 - YES), that is, until the first temperature condition is satisfied. In the initial supply process, compressed air is supplied into the front spindle device 11 from the front front nozzle 35 and the front rear nozzle 36 to maintain the inside of the front spindle device 11 in a positive pressure state. Note that the initial supply process may be a continuous supply process in which a predetermined amount of compressed air is continuously supplied. Also, the initial supply process may be a continuous supply process in which the same predetermined amount of compressed air as the supply process during machining is continuously supplied.

[0049] At time t1, when the processing unit 45 determines that the first threshold time T th1 has elapsed after the machining process is completed (S103 - YES), the initial supply process is terminated and the first intermittent supply process is started (S104). The first intermittent supply process is a process of periodically supplying compressed air in pulses of the second supply time T<00S103 - YES), the initial supply process is terminated and the first intermittent supply process is started (S104). The first intermittent supply process is a process of periodically supplying compressed air in pulses of the second supply time T P2 P1 + T P2 ). The duty ratio in the first intermittent supply process is T P2 / (T P1 + T P2 ). In the first intermittent supply process, the processing unit 45 performs a first supply process in which the supply of compressed air is stopped for the first supply time T P1 , and after performing the first supply process, a second supply process in which compressed air is supplied for the second supply time T P2 is sequentially executed.

[0050] [[ID=3S103 - YES), the initial supply process is terminated and the first intermittent supply process is started (S\ The first supply time T P1 and the second supply time T P2This is determined by empirical rules, for example, the first supply time T P1 The first is 5 minutes, and the second supply time T P2 This is 1 minute. In other examples, the first supply time T P1 This is 50 seconds, and the second supply time T P2 This is 10 seconds. First supply time T P1 Let this be 50 seconds, and the second supply time T P2 By setting this to 10 seconds, the first supply time T P1 Let this be 5 minutes, and the second supply time T P2 The number of times the second supply process, which supplies compressed air, can be increased sixfold compared to when the first supply is set to one minute.

[0051] First supply time T P1 or 2 supply time T P2 This is determined according to the amount of air flowing from the outside to the inside of the spindle unit 11 and the compressed air supply capacity, as the internal temperature of the spindle unit 11 decreases during the first intermittent supply process. That is, the first supply time T P1 or 2 supply time T P2 It is determined that the amount of compressed air supplied will exceed the amount of air flowing from the outside to the inside of the spindle device 11 during the first intermittent supply process.

[0052] First supply time T in the first intermittent supply process P1 Next, a closing signal is output to the front discharge valve 33 to indicate that it is closing. The front discharge valve 33 transitions to the closed state in response to the input of the closing signal, and the amount of compressed air supplied to the inside of the front spindle device 11 becomes zero. As the front discharge valve 33 transitions to the closed state, the first supply process, which stops the supply of compressed air, begins. The first supply time T begins from the start of the first supply process. P1 The second supply time T after the elapsed time P2 The processing unit 45 then outputs an open signal to the front discharge valve 33 to indicate that it is to open. The front discharge valve 33 transitions to the open state in response to the input of the open signal. As the front discharge valve 33 transitions to the open state, the first supply process ends and the second supply process begins. The second supply time T begins after the start of the second supply process. P2After the specified time has elapsed, the processing unit 45 outputs a closing signal to the front discharge valve 33 to indicate that it is closing. The front discharge valve 33 transitions to the closed state in response to the input of the closing signal. As the front discharge valve 33 transitions to the closed state, the second supply process ends and the first supply process begins.

[0053] Thereafter, the compressed air supply device 30 continuously performs a first intermittent supply process, which involves sequentially repeating a first supply process, which sets the first supply amount (the amount of compressed air supplied) to zero, and a second supply process, which sets the amount of compressed air supplied to a second supply amount (greater than the first supply amount). It is preferable that the first and second supply processes be repeated multiple times. First supply time T P1 and second supply time T P2 The ratio, i.e., the amount of compressed air supplied during the first intermittent supply process, is determined according to the type of cutting fluid used in the machining process, as well as the flow rate and pressure of the cutting fluid. When the viscosity of the cutting fluid used is low, and when the flow rate and pressure of the cutting fluid are high, the first supply time T P1 The length is shortened to increase the amount of compressed air supplied.

[0054] Next, the processing unit 45 performs the first threshold time T after the processing is completed. th1 A second threshold time T that is longer than the second threshold time T th2 It is determined whether the time has elapsed (S105). Second threshold time T th2 This indicates the change in the internal temperature of the front spindle unit 11 after the machining process is completed, and is an example of a second temperature condition that indicates the internal temperature of the front spindle unit 11 is lower than the internal temperature corresponding to the first temperature condition. This condition is determined empirically and is, for example, 60 minutes. The internal temperature of the front spindle unit 11 after the initial feed process is completed is obtained by a temperature sensor placed near the front spindle unit 11, and the second threshold time T is determined according to the obtained temperature. th2 You may decide to do so.

[0055] The processing unit 45 completes the processing after the second threshold time T has elapsed since the completion of the processing. th2When it is determined that the time has elapsed (S105-YES), the first intermittent supply process shown in S104 is executed until the second temperature condition is met. During this time, the first intermittent supply process is executed, and the first and second supply processes are repeated. As a result, any foreign matter that enters the interior of the front spindle device 11 during the first supply process is expelled to the outside of the front spindle device 11 by the compressed air ejected during the second supply process.

[0056] The processing unit 45 completes the processing after the second threshold time T has elapsed since the completion of the processing. th2 When it is determined that the time has elapsed (S105-YES), if the second supply process is being executed, the first intermittent supply process is terminated by terminating the second supply process without executing the first supply process. The processing unit 45 terminates the second threshold time T after the processing is completed. th2 When it is determined that the time has elapsed (S105-YES), if the first supply process is being executed, the second supply process may be executed to terminate the first intermittent supply process. By executing the second supply process to terminate the first intermittent supply process, the processing unit 45 ensures that any foreign matter that entered the interior of the front spindle device 11 during the first supply process is discharged to the outside of the front spindle device 11 by the compressed air ejected during the second supply process.

[0057] The processing unit 45, at time t2, after the completion of the processing, until the second threshold time T th2 When it is determined that the time has elapsed (S105-YES), the first intermittent supply process is terminated and the second intermittent supply process is started (S106). The second intermittent supply process is performed for the second supply time T P2 The pulsed compressed air (T P3 +T P2 This is a process of supplying periodically at a cycle of ). The duty cycle in the second intermittent supply process is T P2 / (T P3 +T P2 ) In the second intermittent supply process, the processing unit 45 performs the first supply time T P1 Third supply time T is longer than P3 A third supply process, which involves stopping the supply of compressed air for a specified period, is performed instead of the first supply process. Third supply time T P3 The first supply time T is determined by empirical rules, for example, 5 minutes. P1This is 10 minutes, which is twice the length of the previous one. The third supply time T P3 This is the first supply time T P1 It is not required to specify that the length be twice as long, but rather that it be specified to be an integer multiple of three or more times that length.

[0058] The processing unit 45 completes the processing after the second threshold time T has elapsed since the completion of the processing. th2 The system determines that the time has elapsed (S105-YES), and after completing the first intermittent supply process, it starts the second intermittent supply process (S106). When the second intermittent supply process starts, the processing unit 45 outputs a closing signal to the front discharge valve 33 to indicate that it is closing. The front discharge valve 33 transitions to a closed state in response to the input of the closing signal, and the amount of compressed air supplied to the inside of the front spindle device 11 becomes zero. As the front discharge valve 33 transitions to a closed state, the third supply process, which stops the supply of compressed air, begins.

[0059] From the start of the third supply process until the third supply time T P3 After the specified time has elapsed, the processing unit 45 outputs an open signal to the front discharge valve 33 to indicate that it is to open. The front discharge valve 33 transitions to the open state in response to the input of the open signal. As the front discharge valve 33 transitions to the open state, the third supply process ends and the second supply process begins. The second supply time T begins after the start of the second supply process. P2 After the specified time has elapsed, the processing unit 45 outputs a closing signal to the front discharge valve 33 to indicate that it is closing. The front discharge valve 33 transitions to the closed state in response to the input of the closing signal. As the front discharge valve 33 transitions to the closed state, the second supply process ends and the third supply process begins. Thereafter, the compressed air supply device 30 continuously executes the second intermittent supply process, which sequentially repeats the third supply process and the second supply process. It is preferable that the third supply process and the second supply process be repeated multiple times. Furthermore, the third supply time T P3 This is the first supply time T P1 The third supply time T is not specified to be twice the length of the previous one. P3 and second supply time T P2 The total time for the second intermittent supply process is the first supply time T. P1 and second supply time T P2The time may be specified to be an integer multiple, such as twice the time of the first intermittent supply process, which is the sum of the two times.

[0060] Next, the processing unit 45 performs the second threshold time T after the processing is completed. th2 A termination threshold time T longer than this is required. thf Determine whether the time has elapsed (S107). Termination threshold time T thf This indicates the change in the internal temperature of the front spindle unit 11 after the machining process is completed, and is an example of a completion temperature condition that shows that the internal temperature of the front spindle unit 11 is lower than the internal temperature corresponding to the second temperature condition. This condition is determined empirically and is, for example, 93 minutes. The internal temperature of the front spindle unit 11 after the second intermittent feeding process is completed is obtained by a temperature sensor placed near the front spindle unit 11, and the completion threshold time T is determined according to the obtained temperature. th2 You may decide to do so.

[0061] The processing unit 45 completes the processing after the completion of the machining process, and the completion threshold time T thf When it is determined that the time has elapsed (S107-YES), the second intermittent supply process is executed until the termination temperature condition is met. During this time, the second intermittent supply process is executed, and the third supply process and the second supply process are repeated, so that any foreign matter that has entered the interior of the front spindle device 11 during the third supply process is discharged to the outside of the front spindle device 11 by the compressed air that is ejected during the second supply process.

[0062] The processing unit 45, at time t3, has completed the processing and a predetermined termination threshold time T has passed. thf When it is determined that the time has elapsed (S107-YES), the second intermittent supply process is terminated and the supply termination process is executed (S108). The processing unit 45 determines the termination threshold time T after the processing is completed. thf When it is determined that the time has elapsed (S107-YES), if the third supply process is being executed, the second intermittent supply process is terminated without executing the second supply process. The processing unit 45 determines the termination threshold time T after the processing is completed. thfWhen it is determined that the time has elapsed (S107-YES), if the second supply process is being executed, the second intermittent supply process is terminated by ending the second supply process without executing the third supply process. The processing unit 45 terminates the second intermittent supply process after the processing is completed, which is the termination threshold time T. thf When it is determined that the time has elapsed (S107-YES), if the third supply process is being executed, the second supply process may be executed to terminate the second intermittent supply process. By executing the second supply process to terminate the second intermittent supply process, the processing unit 45 ensures that any foreign matter that entered the interior of the front spindle device 11 during the third supply process is discharged to the outside of the front spindle device 11 by the compressed air ejected during the second supply process.

[0063] (Effects of the machine tool according to the embodiment) When the machine tool 1 supplies compressed air into the spindle unit 11 after the machining process is completed, the first threshold time T of the initial supply process th1 After a certain period has elapsed, the first intermittent supply process is executed to reduce the amount of compressed air supplied to the spindle unit 11 in accordance with the decrease in the internal temperature of the spindle unit 11. By reducing the amount of compressed air supplied to the spindle unit 11 in accordance with the decrease in the internal temperature of the spindle unit 11, the machine tool 1 can reduce the total amount of compressed air supplied to the spindle unit 11 after the machining process is completed. By reducing the total amount of compressed air supplied to the spindle unit 11 after the machining process is completed, the machine tool 1 can reduce the operating time of the compressor 31 that generates the compressed air, thereby suppressing an increase in environmental load.

[0064] Furthermore, the machine tool 1 has a second threshold time T. th2 After the specified time has elapsed, a second intermittent supply process is performed in which the time during which compressed air is not supplied is longer than that of the first intermittent supply process, thereby further reducing the amount of compressed air supplied to the spindle unit 11. By performing the second intermittent supply process, the machine tool 1 reduces the total amount of compressed air supplied to the spindle unit 11 after the machining process is completed, further reducing the operating time of the compressor 31 that generates the compressed air, and further suppressing the increase in environmental load.

[0065] Figure 5(a) shows the change in internal temperature of the front spindle unit 11 after the machining process is completed, and Figure 5(b) shows the relationship between the internal temperature of the front spindle unit 11 and the volume of air retained inside the front spindle unit 11. In Figure 5(a), the horizontal axis represents the elapsed time since the machining process was completed, and the vertical axis represents the internal temperature of the front spindle unit 11. In Figure 5(b), the horizontal axis represents the internal temperature of the front spindle unit 11, and the vertical axis represents the volume of air retained inside the front spindle unit 11.

[0066] Furthermore, in Figures 5(a) and 5(b), T0 represents the internal temperature of the front spindle unit 11 at time 0 when the machining process is completed, and T1, T2, and T3 represent the first threshold time T after the machining process is completed. th1 , second threshold time T th2 and termination threshold time T thf The internal temperature of the front spindle unit 11 is shown for each of the following conditions. Also, in Figure 5(b), V0 represents the volume of air remaining inside the front spindle unit 11 when the internal temperature of the front spindle unit 11 is temperature T0. In Figure 5(b), V1, V2, and V3 represent the volume of air that was remaining inside the front spindle unit 11 when the internal temperature of the front spindle unit 11 was temperature T0, and the volume of air that was remaining inside the front spindle unit 11 when the internal temperature of the front spindle unit 11 is T1, T2, and T3, respectively.

[0067] As shown in Figure 5(a), the internal temperature of the front spindle unit 11 after the machining process is completed changes exponentially according to a predetermined time constant. Also, as shown in Figure 5(b), the volume of air retained inside the front spindle unit 11 changes in proportion to the change in the internal temperature of the front spindle unit 11, according to Charles's Law. Because the internal temperature of the front spindle unit 11 changes exponentially after the machining process is completed, the rate at which the internal temperature of the front spindle unit 11 decreases from temperature T0 at the end of the machining process to temperature T1 is much faster than the rate at which the internal temperature of the front spindle unit 11 decreases from temperature T1 to temperature T2. From the time the machining process is completed until the first threshold time T th1Because the rate of change in the internal temperature of the front spindle unit 11 is rapid until the time elapsed, when the machining process is completed the volume of gas that was retained inside the front spindle unit 11 contracts, creating negative pressure inside the front spindle unit 11, and there is a risk that foreign matter may enter the front spindle unit 11 from the outside. From the time the machining process is completed until the first threshold time T th1 Until that time has elapsed, in order to prevent foreign matter from entering the interior of the front spindle unit 11, the machine tool 1 performs an initial supply process of supplying compressed air to the interior of the front spindle unit 11.

[0068] The rate at which the internal temperature of the front spindle 11 decreases from temperature T1 to temperature T2 is slower than the rate at which the internal temperature of the front spindle 11 decreases from temperature T0 to temperature T1. Because the rate at which the internal temperature of the front spindle 11 decreases from temperature T1 to temperature T2 is relatively slow, the first threshold time T th1 After the time has elapsed, although the inside of the front spindle unit 11 will be under negative pressure, the risk of foreign matter entering the front spindle unit 11 from the outside will be reduced. The machine tool 1 will have a first threshold time T th1 After the period has elapsed, the second threshold time T th2 Until the time elapses, the machine tool 1 performs a first intermittent supply process, which intermittently supplies compressed air into the front spindle device 11. th1 After the period has elapsed, the second threshold time T th2 By performing the first intermittent supply process until the specified time has elapsed, the operating time of the compressor that generates compressed air is reduced, thereby suppressing the increase in environmental burden.

[0069] The rate at which the internal temperature of the front spindle 11 decreases from temperature T2 to temperature T3 is even slower than the rate at which the internal temperature of the front spindle 11 decreases from temperature T1 to temperature T2. Because the rate at which the internal temperature of the front spindle 11 decreases from temperature T2 to temperature T3 is very slow, the second threshold time T th2 After the time has elapsed, although the inside of the front spindle unit 11 will be under negative pressure, the risk of foreign matter entering the inside of the front spindle unit 11 from the outside will be further reduced. The machine tool 1 will reach the second threshold time T th2After a certain period has elapsed, a second intermittent supply process is performed in which compressed air is not supplied to the inside of the front spindle device 11 for a longer period than the first intermittent supply process. By performing the second intermittent supply process after the first intermittent supply process has elapsed, the machine tool 1 can further reduce the operating time of the compressor that generates compressed air, thereby further suppressing the increase in environmental load.

[0070] Furthermore, the machine tool 1 reduces the amount of compressed air supplied to the front spindle unit 11 by an intermittent supply process that includes a period of time when no compressed air is supplied to the front spindle unit 11. Therefore, the amount of compressed air supplied can be reduced without using a relatively expensive flow control valve. Because the machine tool 1 reduces the amount of compressed air supplied without using a relatively expensive flow control valve, manufacturing costs can be reduced compared to when a flow control valve is used.

[0071] Furthermore, the machine tool 1 has a first threshold time T. th1 , second threshold time T th2 and termination threshold time T thf Since the supply state of compressed air to the spindle unit 11 is switched based on this, the machine tool 1 does not have detection sensors such as temperature sensors and pressure sensors to detect the temperature conditions inside the spindle unit 11. Because the machine tool 1 does not have sensors to detect the temperature conditions inside the spindle unit 11, manufacturing costs can be reduced compared to when the temperature conditions inside the spindle unit 11 are detected by detection sensors.

[0072] In the machine tool 1, the front - part front jet outlet 35 is arranged outside the front - spindle 11a's extending direction with respect to the front - part front bearing 11c, and the front - part rear jet outlet 36 is arranged outside the front - spindle 11a's extending direction with respect to the front - part rear bearing 11d. In the machine tool 1, the front - part front jet outlet 35 and the front - part rear jet outlet 36 are arranged so as to sandwich the front - part front bearing 11c, the front - part rear bearing 11d, and the front motor 11e. The machine tool 1 arranges the front - part front jet outlet 35 and the front - part rear jet outlet 36 so as to sandwich the front - part front bearing 11c to the front motor 11e, so that the pressure around the front - part front bearing 11c to the front motor 11e when compressed air is ejected can be increased. The machine tool 1 can efficiently discharge foreign matter around the front - part front bearing 11c to the front motor 11e to the outside of the front - spindle device 11 by increasing the pressure around the front - part front bearing 11c to the front motor 11e when compressed air is ejected. Note that the internal temperatures T0, T1, T2, and T3, the volumes of air V0, V1, V2, and V3, the first threshold time T th1 , the second threshold time T th2 and the end threshold time T thf shown in FIGS. 5(a) and 5(b) are examples, and are actually determined based on empirical rules or the temperature of the front - spindle device 11, etc.

[0073] (Modification example of the machine tool according to the embodiment) In the machine tool 1, the compressed - air supply device 30 supplies compressed air, but in the machine tool according to the embodiment, the supply device may be a compressed - fluid supply device that supplies a compressed fluid other than compressed air, such as compressed gas containing compressed nitrogen.

[0074] Also, in the machine tool 1, the compressed - air supply device 30 has a control device 4 that executes a compressed - air supply process, but in the machine tool according to the embodiment, the compressed - air supply device may not have a control device, and the compressed - air supply process may be executed by the NC device 20.

[0075] Furthermore, while the machine tool 1 has a front spindle unit 11 and a rear spindle unit 12, the machine tool according to this embodiment may have only the front spindle unit 11 and not the rear spindle unit 12. Also, while the machine tool 1 has a guide bushing device 13, the machine tool according to this embodiment may not have a guide bushing device 13.

[0076] Furthermore, in the machine tool 1, the compressed air supply device 30 has a front front nozzle 35 and a front rear nozzle 36 located inside the front spindle unit 11, and a rear front nozzle 37 and a rear rear nozzle 38 located inside the rear spindle unit 12. However, in the machine tool 1 according to this embodiment, the compressed air supply device 30 only needs to have at least one front nozzle located inside the front spindle unit 11 and at least one rear nozzle located inside the rear spindle unit 12. For example, in the machine tool 1 according to this embodiment, the compressed air supply device 30 may have a single front nozzle located near the front motor 11e of the front spindle unit 11, and a single rear nozzle located near the rear motor 12e of the rear spindle unit 12.

[0077] Furthermore, in the machine tool 1, the front nozzle 35 is positioned outside the extension direction of the front spindle 11a relative to the front bearing 11c, and the rear nozzle 36 is positioned outside the extension direction of the front spindle 11a relative to the rear bearing 11d. Also, the rear front nozzle 37 is positioned outside the extension direction of the rear spindle 12a relative to the rear front bearing 12c, and the rear rear nozzle 38 is positioned outside the extension direction of the rear spindle 12a relative to the rear rear bearing 12d. However, in the machine tool 1 according to this embodiment, the front nozzle 35 and the rear nozzle 36 may be positioned inside the front spindle device 11, including the vicinity of the front bearing 11c and the rear bearing 11d. Also, the rear front nozzle 37 and the rear rear nozzle 38 may be positioned inside the rear spindle device 12, including the vicinity of the rear front bearing 12c and the rear rear bearing 12d.

[0078] Furthermore, while the machine tool 1 has a front discharge valve 33 and a rear discharge valve 34 which are solenoid valves, the machine tool according to this embodiment may have a front discharge valve and a rear discharge valve that are flow control valves instead of the front discharge valve 33 and the rear discharge valve 34.

[0079] Figure 6 is a block diagram of the front spindle unit, rear spindle unit, NC unit, and feed unit of the modified machine tool.

[0080] The modified machine tool differs from machine tool 1 in that it has a compressed supply device 50 instead of a compressed air supply device 30. The compressed supply device 50 differs from the compressed air supply device 30 in that it has a front discharge valve 53, a rear discharge valve 54, and a control device 60 instead of a front discharge valve 33, a rear discharge valve 34, and a control device 40. The control device 60 differs from the control device 40 in that it has a processing unit 65 instead of a processing unit 45. The configuration and function of the components of the modified machine tool other than the front discharge valve 53, the rear discharge valve 54, and the processing unit 65 are the same as the configuration and function of the components of machine tool 1, so a detailed explanation is omitted here.

[0081] Each of the front discharge valve 53 and the rear discharge valve 54 is a flow control valve whose opening and closing operation is controlled by the control device 60 to enable operation at intermediate openings set by the control device 60, and is connected to the pressure tank 32 via piping 39. Each of the front discharge valve 53 and the rear discharge valve 54 supplies compressed air in an amount corresponding to the opening degree set by the control device 60 to the front front nozzle 35 and the front rear nozzle 36, and the rear front nozzle 37 and the rear rear nozzle 38.

[0082] The processing unit 65 has one or more processors and their peripheral circuits. The processing unit 65 comprehensively controls the overall operation of the control device 60 and is, for example, a CPU. The processing unit 65 executes processing based on programs (driver programs, operating system programs, application programs, etc.) stored in the storage unit 42. The processing unit 65 can also execute multiple programs (application programs, etc.) in parallel.

[0083] (Compressed air supply process performed by the modified machine tool) Figure 7 is a flowchart of the compressed air supply process for the first modified machine tool performed by the modified machine tool, and Figure 8 is a timing chart of the compressed air supply process shown in Figure 7. The compressed air supply processes shown in Figures 7 and 8 are performed mainly by the control device 60 in cooperation with each element of the modified machine tool, based on a work processing program stored in the storage unit 42 in advance. The compressed air supply processes shown in Figures 7 and 8 show the process of supplying compressed air around the front spindle 11a, but the process of supplying compressed air around the rear spindle 12a is performed in the same way as the compressed air supply processes shown in Figures 7 and 8. In addition, the compressed air supply processes shown in Figures 7 and 8 are performed after the processing process of machining the workpiece W using the front spindle device 11 and the tool post 14 is completed. The flowchart shown in Figure 7 shows the processes after the start of the processing. The processes shown in S201 to S203 are the same as the processes shown in S101 to S103, so a detailed explanation is omitted here.

[0084] The processing unit 65, at time t1, has completed the processing and the first threshold time T of the initial supply process has passed. th1 The initial supply process is performed until it is determined that the specified time has elapsed (S203-YES), that is, until the first temperature condition is met. During the initial supply process, compressed air is supplied to the interior of the front spindle device 11 from the front front nozzle 35 and the front rear nozzle 36 to maintain a positive pressure state inside the front spindle device 11. The initial supply process may also be a continuous supply process in which a predetermined amount of compressed air is supplied continuously. Alternatively, the initial supply process may also be a continuous supply process in which compressed air is supplied continuously at the same predetermined amount as the supply process during machining.

[0085] The processing unit 65, at time t1, after the completion of the processing, the first threshold time T th1 When it is determined that the time has elapsed (S203-YES), the initial supply process is terminated and the first reduction supply process is started (S204). In the first reduction supply process, the processing unit 65 determines the first supply time T P1 A first supply process involves supplying compressed air with a reduced supply rate over a certain period of time, and after the first supply process is performed, a second supply time T P2The second supply process for supplying compressed air with an increased supply amount is sequentially executed over a certain period.

[0086] In the first reduced supply process, the first supply time T P1 In this case, a closing operation signal indicating that the opening degree is set to a predetermined opening and closing degree such as 20% or 30% is output to the front discharge valve 53. The front discharge valve 53 transitions to a state where the opening degree is the predetermined opening and closing degree in response to the input of the closing operation signal. When the front discharge valve 53 transitions to a state where the opening degree is the predetermined opening and closing degree, the first supply process for reducing the supply amount of compressed air is started. After the first supply time T P1 has elapsed, in the second supply time T P2 In this case, the processing unit 65 outputs an opening operation signal indicating that the opening degree is set to 100% to the front discharge valve 53. The front discharge valve 53 transitions to a state where the opening degree is 100% in response to the input of the opening operation signal. When the front discharge valve 53 transitions to a state where the opening degree is 100%, the first supply process ends and the second supply process starts. After the second supply time T P2 has elapsed, the processing unit 65 outputs a closing operation signal indicating that the opening degree is set to the predetermined opening and closing degree to the front discharge valve 53. The front discharge valve 53 transitions to a state where the opening degree is the predetermined opening and closing degree in response to the input of the closing operation signal. When the front discharge valve 53 transitions to a state where the opening degree is the predetermined opening and closing degree, the second supply process ends and the first supply process starts. Thereafter, the compressed air supply device 50 continuously executes the first reduced supply process in which the first supply process with the supply amount of compressed air being the first supply amount and the second supply process with the supply amount of compressed air being the second supply amount greater than the first supply amount are sequentially repeated.

[0087] Next, the processing unit 65 determines, in the same manner as the process shown in S105, whether or not a second threshold time T th1 longer than the first threshold time T th2 has elapsed after the processing is completed (S205). The processing unit 65 executes the first reduced supply process shown in S204 until it is determined that the second threshold time T th2 has elapsed after the processing is completed (S205 - YES).

[0088] At time t2, the processing unit 65 has completed the machining process and the second threshold time T th2 When it is determined that the time has elapsed (S205-YES), the first reduced supply process is terminated and the second reduced supply process is started (S206). In the second reduced supply process, the processing unit 65 determines the first supply time T P1 Third supply time T is longer than P3 A third supply process, which reduces the amount of compressed air supplied over a certain period, is performed instead of the first supply process.

[0089] The processing unit 65 completes the processing after the second threshold time T th2 The system determines that the time has elapsed (S205-YES), and after completing the first reduction supply process, it starts the second reduction supply process (S206). When the second reduction supply process starts, the processing unit 65 outputs a closing operation signal to the front discharge valve 53 indicating that the opening degree should be set to a predetermined closed opening degree, such as 20% or 30%. The front discharge valve 53 transitions to a state where the opening degree is a predetermined closed opening degree in response to the input of the closing operation signal. As the front discharge valve 53 transitions to a state where the opening degree is a predetermined closed opening degree, the third supply process, which reduces the amount of compressed air supplied, starts. From the start of the third supply process until the third supply time T P3 After the time has elapsed, the processing unit 65 outputs an open operation signal to the front discharge valve 53 indicating that the opening degree should be set to 100%. The front discharge valve 53 transitions to a state where the opening degree is 100% in response to the input of the open operation signal. As the front discharge valve 33 transitions to a state where the opening degree is 100%, the third supply process ends and the second supply process begins. The second supply time T begins after the start of the second supply process. P2 After the specified time has elapsed, the processing unit 65 outputs a closing operation signal to the front discharge valve 53 indicating that the opening degree should be set to a predetermined closed opening degree. The front discharge valve 53 transitions to a state where the opening degree is a predetermined closed opening degree in response to the input of the closing operation signal. As the front discharge valve 53 transitions to a state where the opening degree is a predetermined closed opening degree, the second supply process ends and the third supply process begins. Thereafter, the compressed air supply device 50 continuously executes the second reduction supply process, which sequentially repeats the third supply process and the second supply process.

[0090] Next, the processing unit 65, similar to the process shown in S107, performs the processing after the completion of the machining process until the second threshold time T th2 A termination threshold time T longer than this is required. thf The processing unit 65 determines whether the time has elapsed (S207). thf The second reduction supply process shown in S206 is executed until it is determined that the time has elapsed (S207-YES).

[0091] The processing unit 65, at time t3, has completed the processing and a predetermined termination threshold time T has passed. thf When it is determined that the time has elapsed (S207-YES), the second reduction supply process is terminated and the supply termination process is executed (S208). When the processing unit 65 determines that the termination threshold time has elapsed since the end of the processing process (S207-YES), it outputs a fully closed signal to the front discharge valve 53 indicating that the opening degree is 0%. In response to the input of the fully closed signal, the front discharge valve 53 transitions to a state where the opening degree is 0%.

[0092] In the modified machine tool, by continuously supplying compressed air during the first and third supply processes, the risk of foreign matter entering the interior of the front spindle device 11 is reduced compared to machine tool 1, which completely stops the supply of compressed air during the first and third supply processes.

[0093] In the compressed air supply process according to the first modified example, the opening of the front discharge valve 53 in the second supply process is 100% in both the first and second reduced supply processes. However, in the compressed air supply process according to the embodiment, as shown in Figure 9(a), in the compressed air supply process according to the second modified example, the opening of the front discharge valve 53 in the second supply process may be 100% or less. Figure 9(a) is a timing chart of the compressed air supply process according to the second modified example.

[0094] Furthermore, in the compressed air supply process according to the first modified example, in the third supply process of the second reduction supply process, the third supply time T P3 The first supply time T is the length of the first supply process of the first reduction supply process. P1By making it longer than this, the amount of compressed air supplied is reduced. However, in the compressed air supply process according to the embodiment, as shown in Figure 9(b), in the compressed air supply process according to the third modified example, the length of the third supply process of the second reduction supply process is set to the first supply time T which is the length of the first supply process of the first reduction supply process. P1 The supply amount in the third supply process may be reduced while maintaining the same configuration. In the compressed air supply process according to this embodiment, the length of the third supply process in the second reduction supply process may be made shorter than the length of the first supply process in the first reduction supply process, and the supply amount in the third supply process in the second reduction supply process may be made less than the supply amount in the first supply process in the first reduction supply process. Figure 9(b) is a timing chart of the compressed air supply process according to the third modified example.

[0095] Furthermore, in the compressed air supply process according to the first modified example, the amount of compressed air supplied in the first reduction supply process and the second supply process of the second reduction supply process are the same. However, in the compressed air supply process according to the embodiment, as shown in Figure 10(a), in the compressed air supply process according to the fourth modified example, the amount of compressed air supplied in the second supply process of the second reduction supply process may be less than the amount of compressed air supplied in the second supply process of the first reduction supply process. Figure 10(a) is a timing chart of the compressed air supply process according to the fourth modified example.

[0096] Furthermore, in the compressed air supply process according to the embodiment, the supply amounts for the first reduction supply process and the second reduction supply process should be set such that the supply amount per unit time over the second reduction supply process period is less than the supply amount per unit time over the first reduction supply process period. For example, in the compressed air supply process according to the embodiment, as shown in Figure 10(b), in the compressed air supply process according to the fifth modified example, the pulse width and height in the second reduction supply process may be made smaller than the pulse width and height in the first reduction supply process, and the duty cycle in the second reduction supply process may be made smaller than the duty cycle in the first reduction supply process, while the supply amount of the third supply process of the second reduction supply process may be made smaller than the supply amount of the first supply process of the first reduction supply process. Figure 10(b) is a timing chart of the compressed air supply process according to the fifth modified example.

[0097] Furthermore, in the compressed air supply process according to the first modified example, the supply amounts in the first and third supply processes differ from the supply amounts in the second supply process in the first and second reduction supply processes. However, in the compressed air supply process according to the embodiment, as shown in Figure 11, in the compressed air supply process according to the sixth modified example, if the supply amount per unit time of the second reduction supply process is less than the supply amount per unit time of the first reduction supply process, the supply amounts in the first and second reduction supply processes may be constant. Figure 11 is a timing chart of the compressed air supply process according to the sixth modified example.

[0098] Furthermore, the machine tool 1 has a first threshold time T. th1 , second threshold time T th2 and termination threshold time T thf In other words, the supply state of compressed air to the spindle device 11 is switched based on the time elapsed since the machining process was completed and the front spindle 11a stopped rotating. However, in the machine tool 1 according to this embodiment, the supply state of compressed air to the spindle device 11 may be switched when the number of times the second supply process for supplying compressed air has been performed reaches a predetermined threshold number.

[0099] Furthermore, the machine tool 1 has a first threshold time T. th1 , second threshold time T th2 and termination threshold time T thf In other words, the supply state of compressed air to the spindle device 11 is switched based on the time elapsed since the machining process was completed and the front spindle 11a stopped rotating. However, in the machine tool 1 according to this embodiment, the supply state of compressed air to the spindle device 11 may also be switched based on a first temperature condition, a second temperature condition, and a completion temperature condition indicating the internal temperature of the spindle device 11, other than the time elapsed since the machining process was completed.

[0100] For example, the machine tool 1 according to the embodiment may switch the supply state of compressed air to the spindle device 11 based on the internal temperature detected by a temperature sensor that detects the internal temperature of the spindle device 11. When the internal temperature detected by the temperature sensor drops to a first threshold temperature, the machine tool 1 according to the embodiment switches from an initial supply process that supplies compressed air to the spindle device 11 to a first intermittent supply process that intermittently supplies compressed air to the spindle device 11. Furthermore, when the internal temperature detected by the temperature sensor drops to a second threshold temperature, the machine tool 1 according to the embodiment switches from the first intermittent supply process to a second intermittent supply process in which the time during which compressed air is not supplied to the spindle device 11 is longer than that of the first intermittent supply process. Finally, when the internal temperature detected by the temperature sensor drops to a termination threshold temperature, the machine tool 1 according to the embodiment terminates the supply of compressed air to the spindle device 11. The first threshold temperature is another example of the first temperature condition, the second threshold temperature is another example of the second temperature condition, and the termination threshold temperature is another example of the termination temperature condition. Furthermore, the machine tool 1 according to this embodiment may have a pressure sensor for detecting the internal pressure of the spindle device 11, and the supply state of compressed air to the inside of the spindle device 11 may be switched based on the internal pressure detected by the pressure sensor.

[0101] Furthermore, the machine tool 1 performs two intermittent supply processes, a first intermittent supply process and a second intermittent supply process, but the machine tool according to the embodiment may perform one or three or more intermittent supply processes. Also, in the compressed air supply process according to the first modified example described with reference to Figures 8 and 7, two reduction supply processes, a first reduction supply process and a second reduction supply process, are performed, but in the compressed air supply process according to the embodiment, one or three or more reduction supply processes may be performed.

[0102] Furthermore, although the description above assumes that the machine tool 1 has a compressed air supply device 30, the machine tool 1 is not limited to this, and compressed air may be supplied from a separate compressed air supply device 30 without the machine tool 1 having its own compressed air supply device 30.

[0103] 1. Machine tool 11. Front spindle unit (spindle unit) 12. Rear spindle unit (spindle unit) 13. Guide bush unit 14. Tool post 20. NC unit 30, 50. Compressed air supply unit (compressed fluid supply unit)

Claims

1. A machine tool comprising: a spindle device having a spindle, a housing for the spindle, and bearings disposed inside the housing for rotatably supporting the spindle; and a compressed fluid supply device for supplying compressed fluid to the spindle device, wherein the compressed fluid supply device performs an initial supply process to supply compressed fluid to the spindle device until a predetermined first temperature condition is met after machining by the spindle device is completed; performs a first reduction supply process to supply compressed fluid to the spindle device by reducing the amount of compressed fluid supplied per unit time when the first temperature condition is met; and performs a supply termination process to terminate the supply of compressed fluid when a predetermined termination temperature condition is met.

2. The machine tool according to claim 1, wherein in the first reduced supply process, the compressed fluid supply device performs a first supply process of supplying compressed fluid at a first supply amount for a first supply time, and after performing the first supply process, performs a second supply process of supplying compressed fluid at a second supply amount greater than the first supply amount for a second supply time.

3. The machine tool according to claim 2, wherein the compressed fluid supply device further performs a second reduction supply process in which, when a second temperature condition is further met indicating that the internal temperature of the spindle device is lower than the internal temperature corresponding to the first temperature condition, the amount of compressed fluid supplied per unit time is reduced compared to the first reduction supply process and compressed fluid is supplied to the inside of the spindle device.

4. The machine tool according to claim 3, wherein the compressed fluid supply device, when the second temperature condition is further satisfied, performs the second supply process after performing the first supply process.

5. The machine tool according to claim 3, wherein in the second reduction supply process, the compressed fluid supply device performs a third supply process in which it supplies compressed fluid at the first supply amount for a third supply time longer than the first supply time, and after performing the third supply process, it performs the second supply process.

6. The machine tool according to claim 5, wherein the compressed fluid supply device, when the termination temperature condition is further satisfied, performs the second supply process after performing the third supply process.

7. The machine tool according to claim 5, wherein the compressed fluid supply device sets the first supply amount to zero in the first supply process and the third supply process.

8. The machine tool according to claim 6, wherein the initial supply process is a continuous supply process in which compressed fluid is continuously supplied at the second supply rate.

9. The machine tool according to claim 7, wherein the first temperature condition, the second temperature condition, and the termination temperature condition are the time elapsed since the spindle stopped rotating, the time corresponding to the second temperature condition is longer than the time corresponding to the first temperature condition, and the time corresponding to the termination temperature condition is longer than the time corresponding to the second temperature condition.

10. The machine tool according to any one of claims 1 to 9, wherein the compressed fluid supply device is positioned on the outside of the extension direction of the main shaft with respect to the bearing and has a nozzle for ejecting compressed fluid.

11. The machine tool according to claim 10, wherein the bearing includes a front bearing disposed at the front of the main shaft and a rear bearing disposed at the rear of the main shaft, and the nozzle includes a front nozzle disposed outward in the direction of extension of the main shaft relative to the front bearing and a rear nozzle disposed outward in the direction of extension of the main shaft relative to the rear bearing.

12. A compressed fluid supply device for supplying compressed fluid to the interior of a spindle device having a spindle, a housing for the spindle, and bearings disposed inside the housing and rotatably supporting the spindle, characterized in that, after machining by the spindle device is completed, an initial supply process is performed to supply compressed fluid to the interior of the spindle device until a predetermined first temperature condition is met; when the first temperature condition is met, a first reduction supply process is performed to supply compressed fluid to the interior of the spindle device by reducing the amount of compressed fluid supplied per unit time; and when a predetermined termination temperature condition is met, a supply termination process is performed to terminate the supply of compressed fluid.

13. A machine tool comprising a spindle, a housing for the spindle, a spindle device disposed inside the housing and having bearings that rotatably support the spindle, and a compressed air supply device for supplying compressed fluid to the inside of the spindle device, wherein after machining by the spindle device is completed, an initial supply process is performed to supply compressed fluid to the inside of the spindle device until a predetermined first temperature condition is met; when the first temperature condition is met, a first reduction supply process is performed to supply compressed fluid to the inside of the spindle device by reducing the amount of compressed fluid supplied per unit time; and when a predetermined termination temperature condition is met, a supply termination process is performed to terminate the supply of compressed fluid.

14. A compressed fluid supply program for a machine tool comprising: a spindle device having a spindle, a housing for the spindle, a bearing disposed inside the housing and rotatably supporting the spindle; and a compressed air supply device for supplying compressed fluid to the inside of the spindle device, wherein after machining by the spindle device is completed, an initial supply process is performed to supply compressed fluid to the inside of the spindle device until a predetermined first temperature condition is met; when the first temperature condition is met, a first reduction supply process is performed to supply compressed fluid to the inside of the spindle device by reducing the amount of compressed fluid supplied per unit time; and when a predetermined termination temperature condition is met, a supply termination process is performed to terminate the supply of compressed fluid, the program being controlled by a computer.

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