Main shaft lubricating device of machine tool, machine tool and use method of machine tool

Abstract

The invention provides a spindle lubricating device of a machine tool, the machine tool and a method for using the machine tool. A spindle lubrication device for a machine tool includes a rotating body that holds a tool, a plurality of bearings, a housing, a mixed fluid supply device, and a recovery device that recovers an oil-containing fluid. The recovery device is provided with a plurality of recovery channels, a plurality of ejectors, and a plurality of flow control valves. The plurality of ejectors include: a first ejector that sucks a first oil-containing fluid from a first recovery flow path by generating a negative pressure using first air supplied from a first air flow path; and a second ejector that generates a negative pressure by using second air supplied from the second air flow path, thereby suctioning the second oil-containing fluid from the second recovery flow path. The plurality of flow rate control valves include: a first flow rate control valve that adjusts the flow rate of the first air supplied from the first air flow passage to the first ejector; and a second flow rate control valve that adjusts the flow rate of the second air supplied from the second air flow passage to the second ejector.

Description

Technical Field

[0001] The invention relates to a spindle lubricating device for a machine tool, the machine tool and a method for using the machine tool. Background Art

[0002] A lubricating device for a spindle of a machine tool is known.

[0003] As a related technology, Patent Document 1 discloses a spindle lubrication device. In the spindle lubrication device described in Patent Document 1, a rotating shaft is rotatably supported by a housing via bearings, and the bearings are lubricated by externally supplied lubricating oil. Furthermore, in the spindle lubrication device described in Patent Document 1, the drained oil is sucked under negative pressure by a negative pressure generating device or recovered by natural fall.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-002622 Summary of the Invention

[0005] An object of the present invention is to provide a technology that prevents lubrication failure from occurring in each of a plurality of bearings.

[0006] In some embodiments, a spindle lubrication device for a machine tool includes: a rotating body that holds a tool; a plurality of bearings, including a first bearing and a second bearing; a housing that supports the rotating body rotatably about a first axis via the bearings; a mixed fluid supply device that supplies a mixed fluid comprising oil and air to the bearings; and a recovery device that recovers an oil-containing fluid containing the oil. The recovery device includes: a plurality of recovery channels disposed in the housing that recover the oil-containing fluid from the bearings; a plurality of ejectors disposed outside the housing; and a plurality of flow control valves. The plurality of recovery channels include: a first recovery channel that primarily recovers a first oil-containing fluid discharged from at least one bearing, including the first bearing; and a second recovery channel that primarily recovers a second oil-containing fluid discharged from at least one bearing, including the second bearing. The plurality of ejectors include: a first ejector that uses first air supplied from a first air channel to generate negative pressure, thereby drawing the first oil-containing fluid from the first recovery channel; and a second ejector that uses second air supplied from a second air channel to generate negative pressure, thereby drawing the second oil-containing fluid from the second recovery channel. The plurality of flow control valves include a first flow control valve that adjusts the flow rate of the first air supplied from the first air flow passage to the first ejector; and a second flow control valve that adjusts the flow rate of the second air supplied from the second air flow passage to the second ejector.

[0007] In some embodiments, a machine tool includes: a machining head having: a rotating body for holding a tool; a plurality of bearings, including a first bearing and a second bearing; a housing for rotatably supporting the rotating body via the plurality of bearings; a first rotary drive device for rotating the rotating body about a first axis; a mixed fluid supply device for supplying a mixed fluid comprising oil and air to the plurality of bearings; a recovery device for recovering an oil-containing fluid containing the oil; a workpiece support device for supporting a workpiece; a moving device for moving the machining head relative to the workpiece support device; and a control device for controlling at least the first rotary drive device, the mixed fluid supply device, and the moving device. The recovery device includes: a plurality of recovery flow channels disposed in the housing for recovering the oil-containing fluid from the plurality of bearings; a plurality of ejectors disposed outside the housing; and a plurality of flow control valves. The plurality of recovery flow channels include: a first recovery flow channel for primarily recovering a first oil-containing fluid discharged from at least one bearing, including the first bearing; and a second recovery flow channel for primarily recovering a second oil-containing fluid discharged from at least one bearing, including the second bearing. The plurality of ejectors include: a first ejector that generates negative pressure using first air supplied from a first air flow channel, thereby drawing the first oil-containing fluid from the first recovery flow channel; and a second ejector that generates negative pressure using second air supplied from a second air flow channel, thereby drawing the second oil-containing fluid from the second recovery flow channel. The plurality of flow control valves include: a first flow control valve that adjusts the flow rate of the first air supplied from the first air flow channel to the first ejector; and a second flow control valve that adjusts the flow rate of the second air supplied from the second air flow channel to the second ejector.

[0008] The method for using a machine tool in some embodiments is the method for using the above-mentioned machine tool. The method for using comprises: a process of deriving the first discharge flow rate by measuring or simulating when the flow rate of the first oil-containing fluid discharged from the first recovery flow channel to the outside of the first recovery flow channel is defined as a first discharge flow rate under the second condition that the multiple pipes are separated from the multiple recovery flow channel fluids and the mixed fluid of the first flow rate is supplied from the mixed fluid supply device to the multiple bearings; a process of deriving the second discharge flow rate by measuring or simulating when the flow rate of the second oil-containing fluid discharged from the second recovery flow channel to the outside of the second recovery flow channel is defined as a second discharge flow rate; a process of deriving the second discharge flow rate by measuring or simulating when the flow rate of the first oil-containing fluid flowing in the first pipe is defined as a first recovery flow rate under the first condition that the multiple pipes are respectively connected to the multiple recovery flow channel fluids and the mixed fluid of the first flow rate is supplied from the mixed fluid supply device to the multiple bearings. A process for deriving the first recovery flow rate by simulation; a process for deriving the second recovery flow rate by measurement or simulation when the flow rate of the second oil-containing fluid flowing in the second pipe is defined as the second recovery flow rate under the first condition; a process for deriving the first opening of the first flow control valve so that the ratio of the first recovery flow rate to the first discharge flow rate is within a predetermined range; a process for deriving the second opening of the second flow control valve so that the ratio of the second recovery flow rate to the second discharge flow rate is within a predetermined range; a process for supplying the mixed fluid to the multiple bearings using the mixed fluid supply device; a process for operating the recovery device when the opening of the first flow control valve is set to the first opening and the opening of the second flow control valve is set to the second opening; and a process for processing the workpiece by the tool held on the rotating body and rotating around the first axis.

[0009] According to the present invention, it is possible to provide a technique for preventing lubrication failure from occurring in each of a plurality of bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic cross-sectional view schematically showing a main spindle lubrication device for a machine tool according to a first embodiment. Figure 2 It is a schematic cross-sectional view schematically showing a spindle lubrication device for a machine tool in a comparative example. Figure 3 This is a schematic cross-sectional view schematically showing a spindle lubrication device for a machine tool according to a first modification of the first embodiment. Figure 4 It is a diagram schematically showing how the first recovery flow rate and the second recovery flow rate are measured. Figure 5It is a diagram schematically showing how the oil-containing fluid is discharged from the first recovery flow path and the second recovery flow path to the outside of the housing. Figure 6 It is a schematic cross-sectional view schematically showing a main spindle lubrication device for a machine tool according to a first embodiment. Figure 7 It is a schematic cross-sectional view schematically showing a spindle lubricating device for a machine tool according to a second embodiment. Figure 8 It is a diagram schematically showing how the first recovery flow rate and the second recovery flow rate are measured. Figure 9 It is a diagram schematically showing how the oil-containing fluid is discharged from the first recovery flow path and the second recovery flow path to the outside of the housing. Figure 10 It is a schematic cross-sectional view schematically showing a spindle lubricating device for a machine tool according to a second embodiment. Figure 11 This is a schematic cross-sectional view schematically showing a portion of a spindle lubricating device for a machine tool according to a second embodiment. Figure 12 This is a diagram for explaining an example of the structure of an ejector. Figure 13 This is a schematic cross-sectional view schematically showing a spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 14 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 15 It is a diagram schematically showing how the first recovery flow rate and the second recovery flow rate are measured. Figure 16 It is a diagram schematically showing how the oil-containing fluid is discharged from the first recovery flow path, the second recovery flow path, and the third recovery flow path to the outside of the housing. Figure 17 This is a schematic cross-sectional view schematically showing a spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 18 This is a diagram schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 19 It is a schematic cross-sectional view schematically showing an example of a machining head. Figure 20 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 21 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 22 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 23 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a second modified example of the second embodiment. Figure 24 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 25 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubrication device for a machine tool in a first modified example of the second embodiment. Figure 26 It is a diagram for explaining the first annular groove and the second annular groove. Figure 27 It is a schematic perspective view schematically showing an example of a machine tool in a third embodiment. Figure 28 It is a schematic perspective view schematically showing another example of the machine tool in the third embodiment. Figure 29 This is a diagram schematically showing a case where a control device can control a plurality of control target devices. Figure 30 This is a diagram for explaining an example of the arrangement of the collection container. Figure 31 This is a diagram for explaining another example of the arrangement of the collection container. Figure 32 This is a flowchart showing an example of a method of using a machine tool in the embodiment. DETAILED DESCRIPTION

[0011] Hereinafter, a spindle lubrication device 1 for a machine tool, a machine tool 100, and a method for using the machine tool according to an embodiment will be described with reference to the accompanying drawings. In the following description of the embodiment, parts and components having the same functions are denoted by the same reference numerals, and repeated description of parts and components denoted by the same reference numerals will be omitted.

[0012] (Definition of direction) In this specification, a direction from the rear end portion 22 of the rotating body 2 toward the front end portion 24 of the rotating body 2 is defined as a “first direction DR1 ,” and a direction opposite to the first direction DR1 is defined as a “second direction DR2 .”

[0013] In this specification, a direction approaching the first axis AX1 serving as the rotation axis of the rotating body 2 is defined as a “radially inward direction DR3” or “inward.” Furthermore, a direction away from the first axis AX1 serving as the rotation axis of the rotating body 2 is defined as a “radially outward direction DR4” or “outward.”

[0014] The direction from the rear end 22 of the rotating body 2 toward the front end 24 of the rotating body 2 is, for example, downward or lateral. If the posture of the machining head 10 can be changed, the direction from the rear end 22 of the rotating body 2 toward the front end 24 of the rotating body 2 changes according to the change in the posture of the machining head 10. In this specification, regardless of the actual posture of the machining head 10, the direction from the rear end 22 of the rotating body 2 toward the front end 24 of the rotating body is referred to as the "downward direction," and the direction from the front end 24 of the rotating body 2 toward the rear end 22 of the rotating body is referred to as the "upward direction." Furthermore, in this specification, regardless of the actual posture of the machining head 10, the surface on the side of the first direction DR1 is referred to as the "lower surface," and the surface on the side of the second direction DR2 is referred to as the "upper surface."

[0015] (First embodiment) Reference Figures 1 to 6 Next, a spindle lubricating device 1A for a machine tool according to a first embodiment will be described. Figure 1 It is a schematic cross-sectional view schematically showing a main spindle lubricating device 1A for a machine tool according to the first embodiment. Figure 2 It is a schematic cross-sectional view schematically showing a spindle lubricating device 1A' for a machine tool in a comparative example. Figure 3 This is a schematic cross-sectional view schematically showing a spindle lubricating device 1A for a machine tool according to a first modified example of the first embodiment. Figure 4 It is a diagram schematically showing how the first recovery flow rate and the second recovery flow rate are measured. Figure 5 Schematically shows how the oil-containing fluid is discharged from the first recovery flow path 71 and the second recovery flow path 72 to the outside of the housing 4 . Figure 6 It is a schematic cross-sectional view schematically showing a main spindle lubricating device 1A for a machine tool according to the first embodiment.

[0016] like Figure 1 As illustrated, the spindle lubricating device 1A for a machine tool in the first embodiment includes a rotating body 2 for holding a tool T, a plurality of bearings 3, a housing 4, a mixed fluid supply device 6, and a recovery device 7. The spindle lubricating device 1A for a machine tool may also include a controller 8 for controlling at least the mixed fluid supply device 6.

[0017] exist Figure 1In the example described, the rotating body 2 is a rotating shaft 20. The rotating body 2 is capable of rotating around a first axis AX1. The rotating body 2 (more specifically, the rotating shaft 20) has a rear end portion 22 and a front end portion 24 for holding a tool T. In addition, a tool holder HD for holding the tool T is sometimes mounted on the front end portion 24. In this case, the tool T is held by the front end portion 24 with the aid of the tool holder HD. Therefore, in this specification, the "front end portion 24 for holding the tool" includes both the front end portion 24 for directly holding the tool T and the front end portion 24 for holding the tool T with the aid of the tool holder HD. In other words, in this specification, the front end portion 24 can be configured to directly hold the tool T or to hold the tool T with the aid of the tool holder HD.

[0018] The housing 4 supports the rotating body 2 via a plurality of bearings 3 so as to be rotatable around the first axis AX1. Figure 1 In the described example, the housing 4 is composed of an assembly of a plurality of parts.

[0019] exist Figure 1 In the example described, the spindle lubrication device 1A includes a plurality of bearings 3, and the plurality of bearings 3 include a first bearing 31a and a second bearing 36b. Figure 1 In the example described, the first bearing 31a is the front bearing 31 supporting the front end 24 of the rotating body 2. The second bearing 36b is the rear bearing 36 supporting the rear end 22 of the rotating body 2. Alternatively, the second bearing 36b may be a bearing supporting the middle portion of the rotating body.

[0020] exist Figure 1 In the example described, the spindle lubrication device 1A for a machine tool includes a front bearing 31 that supports the front end portion 24 of the rotating body 2, and a rear bearing 36 that supports the rear end portion 22 of the rotating body 2. The front bearing 31 includes at least one bearing including a first bearing 31a. The front bearing 31 may also include the first bearing 31a and a third bearing 31c. Figure 1 In the example described, the rear bearing 36 includes at least one bearing including the second bearing 36b. The rear bearing 36 may include a plurality of bearings including the second bearing 36b.

[0021] The mixed fluid supply device 6 supplies a mixed fluid consisting of oil and air to the multiple bearings 3. This mixed fluid is sometimes referred to as oil-air. In the oil-air, the air transports the oil. In other words, the air in the oil-air serves as the transport fluid that transports the oil. More specifically, by supplying oil-air to the multiple bearings 3, the flow of compressed air is utilized to continuously supply a small amount of oil to the multiple bearings 3.

[0022] The recovery device 7 recovers the oily fluid containing oil. Figure 1In the example described, the recovery device 7 includes: a plurality of recovery channels (71, 72) disposed in the housing 4; a plurality of ejectors (75a, 75b) disposed outside the housing 4; and a plurality of flow control valves (76a, 76b). The recovery device 7 may also include a plurality of pipes (74a, 74b) fluidically connecting the plurality of recovery channels (71, 72) and the plurality of ejectors (75a, 75b). Alternatively, when the plurality of recovery channels (71, 72) and the plurality of ejectors (75a, 75b) are directly connected, the plurality of pipes (74a, 74b) may be omitted.

[0023] A plurality of recovery channels (71, 72) are provided in the housing 4 to recover the oil-containing fluid from the plurality of bearings 3. Figure 1 In the described example, the plurality of recovery flow channels ( 71 , 72 ) include a first recovery flow channel 71 and a second recovery flow channel 72 .

[0024] The first recovery flow channel 71 is provided in the housing 4 and mainly recovers the oil-containing fluid discharged from at least one bearing including the first bearing 31a. Hereinafter, the oil-containing fluid recovered through the first recovery flow channel 71 is referred to as the "first oil-containing fluid". Figure 1 In the example described, the first recovery flow path 71 mainly recovers the first oil-containing fluid discharged from the front bearing 31. Figure 1 In the described example, all or most of the first recovery flow path 71 is disposed in the housing 4. All or most of the first recovery flow path 71 may be formed of a through hole formed in the housing 4.

[0025] The second recovery flow channel 72 is provided in the housing 4 and mainly recovers the oil-containing fluid discharged from at least one bearing including the second bearing 36b. Hereinafter, the oil-containing fluid recovered through the second recovery flow channel 72 is referred to as the "second oil-containing fluid". Figure 1 In the example described, the second recovery flow path 72 mainly recovers the second oil-containing fluid discharged from the rear bearing 36. Figure 1 In the example described, all or most of the second recovery flow path 72 is disposed in the housing 4. All or most of the second recovery flow path 72 may also be formed by a through hole formed in the housing 4. Figure 1 In the described example, the second recovery flow path 72 is a flow path independent of the first recovery flow path 71 .

[0026] exist Figure 1 In the described example, the plurality of pipes ( 74 a , 74 b ) include a first pipe 74 a and a second pipe 74 b .

[0027] The first pipe 74a connects the first recovery channel 71 to the first ejector 75a disposed outside the housing 4. Figure 1In the example described, the entire first conduit 74a is disposed outside the housing 4. Alternatively, a portion of the first conduit 74a may be disposed inside the housing 4, and most of the first conduit 74a may be disposed outside the housing 4. Figure 1 In the described example, the first ejector 75 a is an ejector that corresponds one-to-one with the first recovery flow channel 71 via the first pipe 74 a .

[0028] The second pipe 74b connects the second recovery flow channel 72 to the second ejector 75b disposed outside the housing 4. Figure 1 In the example described, the entire second conduit 74b is disposed outside the housing 4. Alternatively, a portion of the second conduit 74b may be disposed inside the housing 4, and most of the second conduit 74b may be disposed outside the housing 4. Figure 1 In the described example, the second ejector 75 b is an ejector that corresponds one-to-one with the second recovery flow channel 72 via the second pipe 74 b.

[0029] A plurality of injectors (75a, 75b) are arranged outside the housing. Figure 1 In the described example, the plurality of injectors ( 75 a , 75 b ) include a first injector 75 a and a second injector 75 b .

[0030] The first ejector 75a generates negative pressure by using the air supplied from the first air flow passage 77a, thereby sucking the first oil-containing fluid from the first recovery flow passage 71. Hereinafter, the air supplied from the first air flow passage 77a to the first ejector 75a is referred to as "first air". Figure 1 In the described example, the first ejector 75 a generates negative pressure in the first pipe 74 a using the first air supplied from the first air flow path 77 a , thereby sucking the first oil-containing fluid from the first recovery flow path 71 through the first pipe 74 a .

[0031] The second ejector 75b generates negative pressure by using the air supplied from the second air flow passage 77b, thereby sucking the second oil-containing fluid from the second recovery flow passage 72. Hereinafter, the air supplied from the second air flow passage 77b to the second ejector 75b is referred to as "second air". Figure 1 In the described example, the second ejector 75b generates negative pressure in the second pipe 74b using the second air supplied from the second air flow path 77b, thereby sucking the second oil-containing fluid from the second recovery flow path 72 via the second pipe 74b.

[0032] exist Figure 1In the example described, the plurality of flow control valves (76a, 76b) include a first flow control valve 76a and a second flow control valve 76b. The first flow control valve 76a adjusts the flow rate of the first air supplied from the first air flow passage 77a to the first ejector 75a. The second flow control valve 76b adjusts the flow rate of the second air supplied from the second air flow passage 77b to the second ejector 75b.

[0033] exist Figure 1 In the example described, controller 8 sends control instructions to mixed fluid supply device 6. Upon receiving the control instructions, mixed fluid supply device 6 supplies a mixed fluid containing oil and air (more specifically, oil-air) to the plurality of bearings 3. Alternatively, controller 8 may also control recovery device 7. More specifically, controller 8 sends control instructions to recovery device 7. Upon receiving the control instructions, recovery device 7 recovers the oil-containing fluid.

[0034] In the comparative example, the spindle lubrication device 1A' of the machine tool (refer to Figure 2 ), multiple bearings 3 are fluidically connected to a negative pressure generating device 75' via a pipe 74. Figure 2 In the example described, the flow rate of the oil-containing fluid recovered from the multiple bearings 3 cannot be adjusted for each bearing or each bearing group. Therefore, it is difficult to prevent poor lubrication in each of the multiple bearings. For example, Figure 2 The example described above assumes that the lubrication of the second bearing 36b is adequate, but the recovery of the oil-containing fluid from the first bearing 31a is insufficient. In this case, oil may leak from the gap between the housing 4 and the rotating body 2. Therefore, to prevent this leakage, it is necessary to increase the suction capacity of the negative pressure generating device 75'. However, increasing the suction capacity of the negative pressure generating device 75' will result in excessive recovery of the oil-containing fluid from the second bearing 36b, resulting in poor lubrication of the second bearing 36b.

[0035] exist Figure 2 The example described above assumes a case where the number of bearings included in the front bearing 31 differs from the number of bearings included in the rear bearing 36. Alternatively or additionally, it is assumed that the length of the first conduit 74a differs from the length of the second conduit 74b. In this case, if equal attraction forces are applied to the first and second conduits 74a, 74b to prevent oil leakage from all bearings, bearings may be more likely to be poorly lubricated.

[0036] In this regard, the spindle lubrication device 1A of the machine tool in the first embodiment includes: multiple injectors, including a first injector 75a and a second injector 75b; and multiple flow control valves, including a first flow control valve 76a for adjusting the flow of the first air supplied to the first injector 75a and a second flow control valve 76b for adjusting the flow of the second air supplied to the second injector 75b.

[0037] Therefore, by adjusting the flow rates of the first air and the second air, the flow rate of the recovered oil-containing fluid can be adjusted for each bearing or each bearing group. As a result, lubrication failure can be prevented in each of the plurality of bearings 3 .

[0038] Furthermore, in the first embodiment, oil leakage is suppressed around the machining head 10, thereby preventing or suppressing contamination of the working environment by oil. Therefore, the working environment is improved and the environmental load is reduced.

[0039] (arbitrary additional structure) Next, refer to Figures 1 to 6 Optional additional configurations that may be employed in the spindle lubricating device 1A for a machine tool according to the first embodiment will be described.

[0040] (Air source AS) exist Figure 1 In the example described, the spindle lubrication device 1A for a machine tool has at least one air source AS (e.g., an air compressor). The at least one air source AS supplies first air to the first air flow passage 77a and second air to the second air flow passage 77b. Figure 1 In the example described, the air source AS1 that supplies the first air to the first air passage 77a and the air source AS2 that supplies the second air to the second air passage 77b are the same air source. Alternatively, the air source AS2 that supplies the second air to the second air passage 77b may be a different air source from the air source AS1 that supplies the first air to the first air passage 77a.

[0041] (First air flow passage 77a and second air flow passage 77b) exist Figure 1 In the example described, the recovery device 7 includes a first air flow path 77a for supplying the first air to the first ejector 75a and a second air flow path 77b for supplying the second air to the second ejector 75b. Figure 1 In the described example, the first flow control valve 76 a is disposed in the first air flow passage 77 a , and the second flow control valve 76 b is disposed in the second air flow passage 77 b .

[0042] (Main air flow channel 12) exist Figure 1In the example described, the spindle lubrication device 1A for a machine tool includes a main air flow path 12 that fluidically connects an air source AS to a first air flow path 77a and a second air flow path 77b. Figure 1 In the described example, the main air flow path 12 is branched into a plurality of air flow paths including a first air flow path 77 a and a second air flow path 77 b .

[0043] (On / off valve 13) exist Figure 1 In the example described, the spindle lubrication device 1A for a machine tool includes an on-off valve 13 disposed between the air source AS and the first flow control valve 76a. When the on-off valve 13 is closed, air is not supplied to the first flow control valve 76a. Figure 1 In the example described, the on-off valve 13 is disposed in the main air flow passage 12. In this case, when the on-off valve 13 is open, air is supplied to the first flow control valve 76a and the second flow control valve 76b, and when the on-off valve 13 is closed, air is not supplied to the first flow control valve 76a and the second flow control valve 76b.

[0044] Alternatively, if Figure 3 As illustrated, the spindle lubrication device 1A for a machine tool may include a first on-off valve 13a disposed between the air source AS and the first flow control valve 76a, and a second on-off valve 13b disposed between the air source AS and the second flow control valve 76b. Figure 3 In the example described, the first on-off valve 13a is located in the first air flow passage 77a, and the second on-off valve 13b is located in the second air flow passage 77b. In this case, when the first on-off valve 13a is open, air is supplied to the first flow control valve 76a; when the first on-off valve 13a is closed, air is not supplied to the first flow control valve 76a. Furthermore, when the second on-off valve 13b is open, air is supplied to the second flow control valve 76b; when the second on-off valve 13b is closed, air is not supplied to the second flow control valve 76b.

[0045] (Exhaust duct 78 and exhaust purifier 791) exist Figure 1 In the example described, the recovery device 7 includes an exhaust pipe 78 and a recovery container 792. Additionally, the recovery device 7 may also include an exhaust gas purifier 791.

[0046] The exhaust pipe 78 receives exhaust gas (more specifically, oil-containing fluid) from the plurality of injectors (75a, 75b). Figure 1 In the example described, the exhaust duct 78 fluidically connects the plurality of injectors (75a, 75b) and the exhaust purifier 791. The exhaust duct 78 is composed of, for example, a plurality of pipes.

[0047] The recovery container 792 is fluidly connected to the exhaust pipe 78. Figure 1 In the example described, the recovery container 792 receives the liquid oil contained in the oil-containing fluid from the exhaust pipe 78 via the exhaust purifier 791. Alternatively, the recovery container 792 may receive the oil-containing fluid directly from the exhaust pipe 78 without passing through the exhaust purifier 791.

[0048] exist Figure 1 In the example described, exhaust gas purifier 791 receives oil-containing fluid from multiple ejectors ( 75 a , 75 b ) via exhaust pipe 78 . Furthermore, exhaust gas purifier 791 separates the oil-containing fluid received from exhaust pipe 78 into liquid oil and air. The liquid oil separated from the oil-containing fluid by exhaust gas purifier 791 is stored in a recovery container 792 .

[0049] exist Figure 1 In the example described, most of the oil used to lubricate the multiple bearings 3 is recovered into a recovery container 792 via an exhaust purifier 791. This prevents or suppresses oil contamination around the machining head 10, thereby improving the working environment and reducing the environmental impact.

[0050] (Second embodiment) Reference Figures 7 to 26 Next, a spindle lubricating device 1B for a machine tool according to a second embodiment will be described. Figure 7 It is a schematic cross-sectional view schematically showing a spindle lubricating device 1B for a machine tool according to a second embodiment. Figure 8 It is a diagram schematically showing how the first recovery flow rate and the second recovery flow rate are measured. Figure 9 Schematically shows how the oil-containing fluid is discharged from the first recovery flow path 71 and the second recovery flow path 72 to the outside of the housing 4 . Figure 10 It is a schematic cross-sectional view schematically showing a spindle lubricating device 1B for a machine tool according to a second embodiment. Figure 11 This is a schematic cross-sectional view schematically showing a portion of a spindle lubricating device 1B for a machine tool according to a second embodiment. Figure 12 This is a diagram for explaining an example of the structure of the ejector 75 . Figure 13 This is a schematic cross-sectional view schematically showing a spindle lubricating device 1B for a machine tool in a first modified example of the second embodiment. Figure 14 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubricating device 1B for a machine tool according to a first modified example of the second embodiment. Figure 15 It is a diagram schematically showing how the first recovery flow rate and the second recovery flow rate are measured. Figure 16 Schematically shows how the oil-containing fluid is discharged from the first recovery flow path 71 , the second recovery flow path 72 , and the third recovery flow path 73 to the outside of the housing 4 . Figure 17This is a schematic cross-sectional view schematically showing a spindle lubricating device 1B for a machine tool in a first modified example of the second embodiment. Figure 18 This is a diagram schematically showing a portion of a main spindle lubricating device 1B for a machine tool according to a first modified example of the second embodiment. Figure 19 It is a schematic cross-sectional view schematically showing an example of the machining head 10 . Figures 20 to 22 、 Figure 24 、 Figure 25 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubricating device 1B for a machine tool according to a first modified example of the second embodiment. Figure 23 This is a schematic cross-sectional view schematically showing a portion of a main spindle lubricating device 1B for a machine tool according to a second modified example of the second embodiment. Figure 26 It is a diagram for explaining the first annular groove V1 and the second annular groove V2.

[0051] The second embodiment will be described primarily with respect to the differences from the first embodiment. Furthermore, in the second embodiment, repeated descriptions of matters already described in the first embodiment will be omitted. Therefore, even if not explicitly stated, matters already described in the first embodiment can of course be applied to the second embodiment. Conversely, all matters described in the second embodiment can be applied to the first embodiment.

[0052] like Figure 7 As illustrated, the spindle lubricating device 1B for a machine tool in the second embodiment includes: (1) a rotating body 2 for holding a tool T; (2) a plurality of bearings 3 including a first bearing 31a and a second bearing 36b; (3) a housing 4 for supporting the rotating body 2 so as to be rotatable about a first axis AX1 via the plurality of bearings 3; (4) a mixed fluid supply device 6 for supplying a mixed fluid containing oil and air to the plurality of bearings 3; and (5) a recovery device 7 for recovering an oil-containing fluid containing oil. Alternatively, the spindle lubricating device 1B for a machine tool may also include a controller 8 for controlling at least the mixed fluid supply device 6. The recovery device 7 includes: (6A) a plurality of recovery flow paths (71, 72, 73) provided in the housing 4 for recovering the oil-containing fluid from the plurality of bearings 3; (6B) a plurality of ejectors (75a, 75b, 75c) disposed outside the housing 4; and (6C) a plurality of flow control valves (76a, 76b, 76c). Additionally, the recovery device 7 may also include a plurality of pipes ( 74 a , 74 b , 74 c ) fluidly connecting the plurality of recovery flow passages ( 71 , 72 , 73 ) and the plurality of ejectors ( 75 a , 75 b , 75 c ).

[0053] exist Figure 7In the described example, the plurality of recovery channels (71, 72, 73) include: a first recovery channel 71, which mainly recovers a first oil-containing fluid discharged from at least one bearing including the first bearing 31a; and a second recovery channel 72, which mainly recovers a second oil-containing fluid discharged from at least one bearing including the second bearing 36b.

[0054] exist Figure 7 In the described example, the plurality of pipes ( 74 a , 74 b , 74 c ) include a first pipe 74 a fluidly connecting the first recovery channel 71 to the first ejector 75 a , and a second pipe 74 b fluidly connecting the second recovery channel 72 to the second ejector 75 b .

[0055] exist Figure 7 In the described example, the plurality of ejectors (75a, 75b, 75c) include: a first ejector 75a, which generates a negative pressure in a first pipe 74a by using first air supplied from a first air flow passage 77a, thereby drawing a first oil-containing fluid from a first recovery flow passage 71 via the first pipe 74a; and a second ejector 75b, which generates a negative pressure in a second pipe 74b by using second air supplied from a second air flow passage 77b, thereby drawing a second oil-containing fluid from a second recovery flow passage 72 via the second pipe 74b.

[0056] exist Figure 7 In the described example, the plurality of flow control valves ( 76 a , 76 b , 76 c ) include a first flow control valve 76 a for adjusting the flow rate of the first air supplied from the first air flow passage 77 a to the first ejector 75 a , and a second flow control valve 76 b for adjusting the flow rate of the second air supplied from the second air flow passage 77 b to the second ejector 75 b .

[0057] Based on the above, the main spindle lubricating device 1B for a machine tool in the second embodiment achieves the same effects as the main spindle lubricating device 1A for a machine tool in the first embodiment.

[0058] (arbitrary additional structure) Next, refer to Figures 1 to 26 Optional additional configurations that may be employed in the spindle lubricating device 1B for a machine tool in the second embodiment (or the spindle lubricating device 1A for a machine tool in the first embodiment) will be described.

[0059] (Setting of the First Recovery Flow Rate, the First Discharge Flow Rate, and the Opening Degree of the First Flow Control Valve 76a) exist Figure 4 、 Figure 5 、 Figure 8 、 Figure 9 In the embodiment, it is assumed that the mixed fluid at a first flow rate is supplied from the mixed fluid supply device 6 to each of the plurality of bearings 3 (see arrow AR1 ).

[0060] exist Figure 4 or Figure 8 , it is shown that a plurality of pipes (74a, 74b, ...) are respectively connected to a plurality of recovery channels (71, 72, ...). More specifically, in Figure 4 and Figure 8 In the example described, the first pipe 74a is fluidically connected to the first recovery channel 71, and the second pipe 74b is fluidically connected to the second recovery channel 72. Figure 8 In the described example, the third pipe 74 c is fluidically connected to the third recovery flow channel 73 .

[0061] exist Figure 5 or Figure 9 , a state in which a plurality of pipes (74a, 74b, ...) are separated from a plurality of recovery flow paths (71, 72, ...) is shown. More specifically, Figure 5 and Figure 9 In the example described, the first pipe 74a is separated from the first recovery flow channel 71, and the second pipe 74b is separated from the second recovery flow channel 72. Figure 9 In the described example, the third conduit 74 c is fluidically separated from the third recovery flow path 73 .

[0062] like Figure 4 or Figure 8 As shown in the example, the plurality of pipes (74a, 74b, ...) are fluidically connected to the plurality of recovery flow paths (71, 72, ...), and under the first condition CD1, a first flow rate of the mixed fluid is supplied from the mixed fluid supply device 6 to the plurality of bearings 3. The flow rate of the first oil-containing fluid flowing in the first pipe 74a is defined as the first recovery flow rate (refer to Figure 4 、 Figure 8 The first recovery flow rate is derived, for example, by measurement. Figure 4 or Figure 8 In the example described, the spindle lubrication device 1 for a machine tool includes a first flowmeter 11a disposed in the first conduit 74a. In this case, the first flowmeter 11a can be used to measure the first recovery flow rate. Alternatively, the first flowmeter 11a can be removed from the first conduit 74a after measuring the first recovery flow rate. Alternatively, the first flowmeter 11a can remain installed in the first conduit 74a after measuring the first recovery flow rate.

[0063] like Figure 5 or Figure 9 As shown in the example, under the second condition CD2 which is different from the first condition CD1 in that only the plurality of pipes (74a, 74b, ...) are separated from the plurality of recovery channels (71, 72, ...), the flow from the first recovery channel 71 to the outside of the first recovery channel 71 (at Figure 5 or Figure 9 In the example described, the flow rate of the first oil-containing fluid discharged from the first recovery flow channel 71 and the housing 4 is defined as the first discharge flow rate (refer to Figure 5 、 Figure 9 The first discharge flow rate can be derived through measurement or simulation. For example, the first oil-containing fluid ejected from the first recovery channel 71 to the outside of the housing 4 can be recovered in a bag, and the first discharge flow rate can be derived by dividing the volume of the recovered first oil-containing fluid by the recovery time. Alternatively, another spindle lubrication device of the same type as the spindle lubrication device 1 described above, except that it lacks the recovery device 7, can be used to measure the first discharge flow rate.

[0064] The first condition CD1 may include a condition that the rotation angle of the rotating body 2 relative to the housing 4 about the first axis AX1 is maintained. In this case, the second condition CD2 includes a condition that the rotation angle of the rotating body 2 relative to the housing 4 about the first axis AX1 is maintained. Alternatively, the first condition CD1 may include a condition that the rotating body 2 rotates relative to the housing 4 about the first axis AX1 at a predetermined rotation speed (e.g., 20,000 rpm or the maximum rotation speed specified in the design specifications of the spindle lubrication device). In this case, the second condition CD2 includes a condition that the rotating body 2 rotates relative to the housing 4 about the first axis AX1 at the predetermined rotation speed (e.g., 20,000 rpm or the maximum rotation speed specified in the design specifications of the spindle lubrication device).

[0065] The flow rate (i.e., first flow rate) of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 under the first condition CD1 is equal to the flow rate (i.e., first flow rate) of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 under the second condition CD2. Assume that, during operation of the spindle lubrication device 1, the upper limit and lower limit of the flow rate of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 are predetermined. In this case, under both the first condition CD1 and the second condition CD2, the first flow rate of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 is set to any value within a range between the lower limit and the upper limit. Under both the first condition CD1 and the second condition CD2, the first flow rate of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 can be set to the upper limit, the lower limit, or a value smaller than the upper limit and larger than the lower limit.

[0066] exist Figure 6 or Figure 10In the example described above, the opening of the first flow control valve 76a is set so that the first recovery flow rate is within a range of 1 to 1.5 times the first discharge flow rate (more preferably, the first recovery flow rate is within a range of 1 to 1.2 times the first discharge flow rate). The opening of the first flow control valve 76a can be set manually or by the controller 8.

[0067] When the opening of the first flow control valve 76a is manually set, the operator adjusts the opening of the first flow control valve 76a while referring to the value of the first recovery flow indicated by the first flow meter 11a. In this way, the operator manually sets the opening of the first flow control valve 76a so that the first recovery flow is within a range of more than 1 times and less than 1.5 times the first discharge flow. When the opening of the first flow control valve 76a is set by the controller 8, the controller 8 can also automatically adjust the opening of the first flow control valve 76a so that the value of the first recovery flow indicated by the first flow meter 11a is within a range of more than 1 times and less than 1.5 times the first discharge flow. In addition, the first flow meter 11a can be removed from the first pipe 74a after adjusting the first recovery flow, or it can remain installed in the first pipe 74a.

[0068] By setting the first recovery flow rate to at least 1 times the first discharge flow rate, insufficient recovery of the first oil-containing fluid is prevented. This prevents oil from leaking out of the machine tool's spindle lubrication device 1 through the gap between the rotating body 2 and the housing 4. Furthermore, by setting the first recovery flow rate to no more than 1.5 times the first discharge flow rate, excessive recovery of the first oil-containing fluid is prevented. This prevents lubrication problems in at least one bearing, including the first bearing 31a.

[0069] (Setting of the Second Recovery Flow Rate, the Second Discharge Flow Rate, and the Opening Degree of the Second Flow Control Valve 76b) like Figure 4 or Figure 8 As illustrated, under the first condition CD1, the flow rate of the second oil-containing fluid flowing in the second pipe 74b is defined as the second recovery flow rate (refer to Figure 4 、 Figure 8 The second recovery flow rate is derived, for example, by measurement. Figure 4 or Figure 8In the example described, the spindle lubrication device 1 for the machine tool includes a second flowmeter 11b disposed in the second pipe 74b. In this case, the second flowmeter 11b can be used to measure the second recovery flow rate. Alternatively, the second flowmeter 11b can remain installed in the second pipe 74b after measuring the second recovery flow rate.

[0070] like Figure 5 or Figure 9 As shown in the example, under the second condition CD2, the second recovery flow channel 72 is directed to the outside of the second recovery flow channel 72 (at Figure 5 or Figure 9 In the example described, the flow rate of the second oil-containing fluid discharged from the second recovery flow channel 72 and the housing 4 is defined as the second discharge flow rate (refer to Figure 5 、 Figure 9 The second discharge flow rate can be derived through measurement or simulation. For example, the second oil-containing fluid ejected from the second recovery channel 72 to the outside of the housing 4 can be recovered in a bag, and the second discharge flow rate can be derived by dividing the volume of the recovered second oil-containing fluid by the recovery time. Alternatively, another spindle lubrication device of the same type as the spindle lubrication device 1 described above, except that it lacks the recovery device 7, can be used to measure the second discharge flow rate.

[0071] exist Figure 6 or Figure 10 In the example described above, the opening of the second flow control valve 76b is set so that the second recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the second discharge flow rate (more preferably, the second recovery flow rate is within a range of not less than 1 times and not more than 1.2 times the second discharge flow rate). The opening of the second flow control valve 76b can be set manually or by the controller 8.

[0072] When the opening of the second flow control valve 76b is manually set, the operator adjusts the opening of the second flow control valve 76b while referring to the value of the second recovery flow indicated by the second flow meter 11b. In this way, the operator manually sets the opening of the second flow control valve 76b so that the second recovery flow is within a range of more than 1 times and less than 1.5 times the second discharge flow. When the opening of the second flow control valve 76b is set by the controller 8, the controller 8 can also automatically adjust the opening of the second flow control valve 76b so that the value of the second recovery flow indicated by the second flow meter 11b is within a range of more than 1 times and less than 1.5 times the second discharge flow. In addition, the second flow meter 11b can be removed from the second pipe 74b after adjusting the second recovery flow, or it can remain installed in the second pipe 74b.

[0073] By setting the second recovery flow rate to at least 1 times the second discharge flow rate, insufficient recovery of the second oil-containing fluid is prevented. This prevents oil from leaking out of the machining head 10 through the gap between the rotating body 2 and the housing 4. Furthermore, by setting the second recovery flow rate to no more than 1.5 times the second discharge flow rate, excessive recovery of the second oil-containing fluid is prevented. This prevents lubrication problems in at least one bearing, including the second bearing 36b.

[0074] For example, if the multiple pipes (74a, 74b, ...) are long, or if the exhaust pipe 78 is long, the pressure loss of the oil-containing fluid flowing through the pipes increases. In this case, the suction force of the multiple ejectors (75a, 75b, ...) needs to be increased. However, increasing the suction force of the multiple ejectors (75a, 75b, ...) can easily lead to poor lubrication of the bearings. Furthermore, if the number of bearings included in the front bearing 31 differs from the number of bearings included in the rear bearing 36, or if the length of the first pipe 74a differs from the length of the second pipe 74b, lubrication imbalances can easily occur among the multiple bearings. By appropriately setting the openings of the first and second flow control valves 76a, 76b, as described above, poor lubrication of the multiple bearings can be avoided.

[0075] (Multiple bearings 3) The plurality of bearings 3 include a first bearing 31a and a second bearing 36b. Additionally, the plurality of bearings 3 may also include a third bearing 31c. Figure 6 、 Figure 10 In the example described, the third bearing 31c is arranged between the first bearing 31a and the second bearing 36b in the direction along the first axis AX1. The third bearing 31c is, for example, a ball bearing.

[0076] The first bearing 31a constitutes at least a portion of the front bearing 31 that supports the front end portion 24 of the rotating body 2. The first bearing 31a is, for example, a ball bearing. Figure 6 、 Figure 10 In the example described, the first bearing 31a is the bearing that is located closest to the first direction DR1 (in other words, the front end) among the plurality of bearings 3 supporting the rotating body 2. The front bearing 31 supporting the front end portion 24 of the rotating body 2 may also include a plurality of bearings. Figure 6 、 Figure 10 In the described example, the front bearing 31 includes a first bearing 31 a and a third bearing 31 c .

[0077] exist Figure 11 In the example described, the first bearing 31a includes an inner ring 32a, an outer ring 33a, and rolling elements 34a disposed between the inner and outer rings 32a and 33a, respectively. Furthermore, the third bearing 31c includes an inner ring 32c, an outer ring 33c, and rolling elements 34c disposed between the inner and outer rings 32c and 33c, respectively.

[0078] exist Figure 6 、 Figure 10 In the example described, the second bearing 36b constitutes at least a portion of the rear bearing 36 that supports the rear end portion 22 of the rotating body 2. The second bearing 36b is, for example, a roller bearing.

[0079] (Recovery device 7) exist Figure 10 In the example described, the recovery device 7 includes: (1) multiple recovery channels, including a first recovery channel 71, a second recovery channel 72, and a third recovery channel 73; (2) multiple pipes, including a first pipe 74a, a second pipe 74b, and a third pipe 74c; (3) multiple injectors, including a first injector 75a, a second injector 75b, and a third injector 75c; and (4) multiple flow control valves, including a first flow control valve 76a, a second flow control valve 76b, and a third flow control valve 76c.

[0080] The first recovery flow channel 71, the second recovery flow channel 72, the first pipe 74a, the second pipe 74b, the first injector 75a, the second injector 75b, the first flow control valve 76a and the second flow control valve 76b have been described in the first embodiment, so repeated description of their structures is omitted.

[0081] The third recovery channel 73 is provided in the housing 4. Figure 11 In the described example, all or most of the third recovery flow path 73 is disposed in the housing 4. All or most of the third recovery flow path 73 may be formed by a through hole formed in the housing 4.

[0082] The third recovery flow path 73 recovers the oil-containing fluid that has not been recovered by the first recovery flow path 71 but has passed through the first bearing 31a. Hereinafter, the oil-containing fluid recovered through the third recovery flow path 73 is referred to as the "third oil-containing fluid". Figure 10 In the described example, the third recovery flow path 73 is a flow path independent of the first recovery flow path 71 and the second recovery flow path 72 .

[0083] like Figure 10 As shown, the third pipe 74c fluidically connects the third recovery channel 73 to the third ejector 75c disposed outside the housing 4. Figure 10 In the example described, the entire third duct 74c is arranged outside the housing 4. Alternatively, a portion of the third duct 74c may be arranged inside the housing 4, and most of the third duct 74c may be arranged outside the housing 4.

[0084] The third ejector 75c generates negative pressure by using the air supplied from the third air flow passage 77c, thereby sucking the third oil-containing fluid from the third recovery flow passage 73. Hereinafter, the air supplied from the third air flow passage 77c to the third ejector 75c is referred to as "third air". Figure 10 In the example described, the third ejector 75c generates negative pressure in the third pipe 74c by using the third air supplied from the third air flow passage 77c, and sucks the third oil-containing fluid from the third recovery flow passage 73 via the third pipe 74c. Figure 10 In the described example, the third ejector 75 c is an ejector that corresponds one-to-one with the third recovery flow channel 73 via the third pipe 74 c.

[0085] The third flow control valve 76c adjusts the flow rate of the third air supplied from the third air flow passage 77c to the third ejector 75c. The opening of the third flow control valve 76c can be set manually or by the controller 8.

[0086] exist Figure 11 In the example described, the spindle lubrication device 1 for a machine tool includes a third recovery flow channel 73. This third recovery flow channel 73 recovers a third oil-containing fluid containing oil that has not been recovered by the first recovery flow channel 71 but has passed through the first bearing 31a. This effectively prevents the oil that has passed through the first bearing 31a from leaking out of the gap between the rotating body 2 and the front end portion 46 of the housing 4.

[0087] For example, consider a case where it is undesirable for oil to adhere to a workpiece being machined by the tool T. More specifically, consider a case where a workpiece made of a carbon material, which causes problems when oil adheres, is being machined. In this case, the embodiment including the third recovery flow path 73 is useful.

[0088] Furthermore, when machining resin materials, etc., using a tool T, dry machining is sometimes employed. In embodiments including the third recovery flow channel 73, oil leakage from the gap between the rotating body 2 and the front end portion 46 of the housing 4 is suppressed, effectively preventing oil from adhering to the workpiece (e.g., resin material). Therefore, embodiments including the third recovery flow channel 73 are also useful when dry machining is employed.

[0089] In the embodiment including the third recovery flow channel 73, oil leakage from the gap between the rotating body 2 and the front end portion 46 of the housing 4 is suppressed. Therefore, when a coolant is used during workpiece machining (in other words, when machining is not dry), oil is prevented from mixing with the coolant. This reduces the environmental impact.

[0090] exist Figure 10 In the example described, the recovery device 7 includes an exhaust duct 78, an exhaust purifier 791, and a recovery container 792. Figure 10 In the depicted example, the exhaust pipe 78 fluidly connects the first injector 75 a , the second injector 75 b , and the third injector 75 c to the exhaust gas purifier 791 .

[0091] Exhaust purifier 791 receives oil-containing fluid from multiple ejectors ( 75 a , 75 b , 75 c ) via exhaust pipe 78 . Furthermore, exhaust purifier 791 separates the oil-containing fluid received from exhaust pipe 78 into liquid oil and air. The liquid oil separated from the oil-containing fluid by exhaust purifier 791 is recovered in recovery container 792 .

[0092] (Structure of the Injector 75) Figure 12 FIG. 7 shows an example of the structure of the ejector 75. The ejector 75 includes an inlet port 751, an outlet port 752, and a vacuum port 753. When compressed air is supplied to the inlet port 751 of the ejector 75, the fluid to be attracted is drawn into the ejector 75 via the vacuum port 753 of the ejector 75. The compressed air and the fluid to be attracted are discharged from the ejector 75 via the outlet port 752. When the flow rate of the compressed air supplied to the inlet port 751 increases, the flow rate of the fluid to be attracted drawn into the ejector 75 increases. On the other hand, when the flow rate of the compressed air supplied to the inlet port 751 decreases, the flow rate of the fluid to be attracted drawn into the ejector 75 decreases.

[0093] The first ejector 75a has its inlet port 751a connected to the first air flow channel 77a, its outlet port 752a connected to the exhaust duct 78, and its vacuum port 753a connected to the first duct 74a. The second ejector 75b has its inlet port 751b connected to the second air flow channel 77b, its outlet port 752b connected to the exhaust duct 78, and its vacuum port 753b connected to the second duct 74b. The third ejector 75c has its inlet port 751c connected to the third air flow channel 77c, its outlet port 752c connected to the exhaust duct 78, and its vacuum port 753c connected to the third duct 74c.

[0094] (Air supply device 9) like Figure 13 As illustrated, the spindle lubrication system 1 for a machine tool may also include an air supply device 9. The air supply device 9 includes an air source AS (e.g., an air compressor) disposed outside the housing 4; an air supply passage 93 disposed within the housing 4; an air supply pipe 91 connecting the air source AS and the air supply passage 93; and a fourth flow control valve 96.

[0095] exist Figure 13 In the example described, the air supply pipe 91 is arranged outside the housing 4. The air supply pipe 91 supplies air to the air supply passage 93. Hereinafter, the air supplied from the air supply pipe 91 to the air supply passage 93 will be referred to as "fourth air". The fourth flow control valve 96 adjusts the flow rate of the fourth air supplied from the air supply pipe 91 to the air supply passage 93. Figure 13 In the example described, the fourth flow control valve 96 is disposed in the air supply pipe 91. The opening degree of the fourth flow control valve 96 may be set manually or by the controller 8.

[0096] exist Figure 14 In the described example, an air injection port OP1 is formed between the rotating body 2 (more specifically, the rotating shaft 20) and the front end portion 46 of the housing 4. Furthermore, a nozzle 49 is formed in the housing 4. This nozzle 49 ejects fourth air received from the air supply flow path 93 into the gap G between the rotating body 2 and the housing 4. The fourth air ejected from the nozzle 49 forms both a first flow from the gap G toward the third recovery flow path 73 and a second flow from the gap G toward the air injection port OP1.

[0097] The fourth air injected from the air injection port OP1 prevents foreign matter such as chips from entering the housing 4 through the gap G. More specifically, Figure 13In the example described, the fourth air ejected from the air ejection port OP1 forms an air curtain AC around the tool T or the tool holder HD. The air curtain AC prevents foreign matter such as chips from entering the housing 4 through the gap G.

[0098] exist Figure 14 In the example described, the first flow from the gap G toward the third recovery flow passage 73 (more specifically, the flow of the fourth air from the gap G toward the third recovery flow passage 73) pushes the oil E1 that has entered the gap G back toward the third recovery flow passage 73. Therefore, oil leakage from the gap between the rotor 2 and the front end portion 46 of the housing 4 is more effectively suppressed.

[0099] The third recovery flow path 73 contains a relatively large amount of the fourth air (in other words, the fourth air ejected from the ejection port 49) compared to the other recovery flow paths (71, 72). Figure 13 In the example described, the third pipe 74c contains a relatively large amount of the fourth air (in other words, the fourth air ejected from the ejection port 49) compared to the other pipes (74a, 74b). In this case, if equal attraction is applied to the first pipe 74a, the second pipe 74b, and the third pipe 74c, an imbalance in oil recovery is likely to occur among the multiple bearings. Figure 13 In the example described, the suction force acting on the first duct 74a, the suction force acting on the second duct 74b, and the suction force acting on the third duct 74c can be adjusted independently. Therefore, by individually and appropriately setting these suction forces, lubrication failure can be prevented in each of the multiple bearings.

[0100] (Setting the Opening Degree of the First Flow Control Valve 76a and the Opening Degree of the Second Flow Control Valve 76b) exist Figure 15 、 Figure 16 In FIG, it is assumed that the mixed fluid at a first flow rate is supplied from the mixed fluid supply device 6 to the plurality of bearings 3 (see arrow AR1). Figure 15 、 Figure 16 In each case, the fourth air of the second flow rate is supplied to the air supply passage 93 (see arrow AR7). Figure 15 、 Figure 16 In the embodiment, it is assumed that air is injected from the air injection port OP1 (see arrow AR6 ).

[0101] exist Figure 15 In FIG, a plurality of pipes (74a, 74b, 74c) are shown to be fluidically connected to a plurality of recovery channels (71, 72, 73). More specifically, in FIG. Figure 15In the described example, the first pipe 74 a is fluidically connected to the first recovery channel 71 , the second pipe 74 b is fluidically connected to the second recovery channel 72 , and the third pipe 74 c is fluidically connected to the third recovery channel 73 .

[0102] exist Figure 16 , a state where a plurality of pipes (74a, 74b, 74c) are separated from a plurality of recovery flow channels (71, 72, 73) is shown. More specifically, Figure 16 In the described example, the first pipe 74 a is fluidically separated from the first recovery flow channel 71 , the second pipe 74 b is fluidically separated from the second recovery flow channel 72 , and the third pipe 74 c is fluidically separated from the third recovery flow channel 73 .

[0103] like Figure 15 As illustrated, under the third condition CD3 in which the plurality of pipes (74a, 74b, 74c) are fluidically connected to the plurality of recovery flow paths (71, 72, 73), the mixed fluid at a first flow rate is supplied from the mixed fluid supply device 6 to the plurality of bearings 3, and the fourth air at a second flow rate is supplied to the air supply flow path 93, the flow rate of the first oil-containing fluid flowing in the first pipe 74a is defined as the first recovery flow rate (refer to Figure 15 In addition, under the third condition CD3, the flow rate of the second oil-containing fluid flowing in the second pipe 74b is defined as the second recovery flow rate (refer to Figure 15 In addition, the measurement methods of the first recovery flow rate and the second recovery flow rate have been described above, and thus repeated description of these measurement methods will be omitted.

[0104] like Figure 16 As illustrated, under the fourth condition CD4, which is different from the third condition CD3 in that only the plurality of pipes (74a, 74b, 74c) are fluidically separated from the plurality of recovery flow paths (71, 72, 73), the flow rate of the first oil-containing fluid discharged from the first recovery flow path 71 to the outside of the first recovery flow path 71 (for example, outside the housing 4) is defined as the first discharge flow rate (refer to Figure 16 In addition, under the fourth condition CD4, the flow rate of the second oil-containing fluid discharged from the second recovery flow channel 72 to the outside of the second recovery flow channel 72 (for example, outside the housing 4) is defined as the second discharge flow rate (refer to Figure 16 In addition, the measurement method (or derivation method) of the first recovery flow rate and the second recovery flow rate has been described above, and therefore repeated description of these measurement methods (or derivation methods) will be omitted.

[0105] The third condition CD3 may also include a condition that the rotation angle of the rotating body 2 relative to the housing 4 about the first axis AX1 is maintained. In this case, the fourth condition CD4 includes a condition that the rotation angle of the rotating body 2 relative to the housing 4 about the first axis AX1 is maintained. Alternatively, the third condition CD3 may include a condition that the rotating body 2 rotates relative to the housing 4 about the first axis AX1 at a predetermined rotation speed (e.g., 20,000 rpm or the maximum rotation speed specified in the design specifications of the spindle lubrication device). In this case, the fourth condition CD4 includes a condition that the rotating body 2 rotates relative to the housing 4 about the first axis AX1 at the predetermined rotation speed (e.g., 20,000 rpm or the maximum rotation speed specified in the design specifications of the spindle lubrication device).

[0106] The flow rate (i.e., first flow rate) of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 under the third condition CD3 is equal to the flow rate (i.e., first flow rate) of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 under the fourth condition CD4. Assume that during operation of the spindle lubrication device 1, the upper limit and lower limit of the flow rate of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 are predetermined. In this case, under the third condition CD3 and the fourth condition CD4, the first flow rate of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 is set to any value within a range between the lower limit and the upper limit. Under the third condition CD3 and the fourth condition CD4, the first flow rate of the mixed fluid supplied from the mixed fluid supply device 6 to the plurality of bearings 3 can be set to the upper limit, the lower limit, or a value smaller than the upper limit and larger than the lower limit.

[0107] The flow rate of the fourth air supplied to the air supply passage 93 under the third condition CD3 (i.e., the second flow rate) is equal to the flow rate of the fourth air supplied to the air supply passage 93 under the fourth condition CD4 (i.e., the second flow rate). Under the fourth condition CD4, the flow rate of the air ejected from the air ejection port OP1 is defined as the "third flow rate." Under the fourth condition CD4 (see Figure 16 ), it is preferred to set the flow rate of the fourth air supplied to the air supply flow channel 93 (i.e., the second flow rate) in such a manner that the third flow rate becomes the flow rate required to form an air curtain (e.g., the flow rate of the design lower limit for forming an air curtain).

[0108] exist Figure 17In the example described, the opening of the first flow control valve 76a is set so that the first recovery flow rate is within a range of 1 to 1.5 times the first discharge flow rate (more preferably, the first recovery flow rate is within a range of 1 to 1.2 times the first discharge flow rate). The opening of the first flow control valve 76a can be set manually or by the controller 8. Furthermore, the opening of the second flow control valve 76b is set so that the second recovery flow rate is within a range of 1 to 1.5 times the second discharge flow rate (more preferably, the second recovery flow rate is within a range of 1 to 1.2 times the second discharge flow rate). The opening of the second flow control valve 76b can be set manually or by the controller 8.

[0109] Furthermore, the third condition CD3 is one aspect of the first condition CD1, and the fourth condition CD4 is one aspect of the second condition CD2.

[0110] (Setting the Opening Degree of the Third Flow Control Valve 76c and the Opening Degree of the Fourth Flow Control Valve 96) exist Figure 17 : shows the state after the opening degree of the first flow control valve 76a and the opening degree of the second flow control valve 76b are set. Figure 17 In the example described, the opening degree of the third flow control valve 76c and the opening degree of the fourth flow control valve 96 are set so that the discharge port 49 (see Figure 14 ) is larger than the flow rate of the fourth air ejected from the air ejection port OP1 (refer to Figure 14 ) The flow rate of the injected air. Figure 14 In the example described, the flow rate of the fourth air ejected from the ejection port 49 is set to be greater than the flow rate of the air ejected from the air ejection port OP1 , thereby preventing or suppressing the ejection of oil E1 from the air ejection port OP1 along with the ejection of air from the air ejection port OP1 .

[0111] For example, if the opening degree of the third flow control valve 76c is small, the recovery of the third oil-containing fluid from the third recovery flow path 73 becomes insufficient. Figure 14 In the example described, oil E1 may flow from the gap between the housing 4 and the rotating body 2 toward the air injection port OP1. More specifically, because the flow rate of air injected from the air injection port OP1 is greater than the flow rate of the fourth air ejected from the ejection port 49, oil E1 may be ejected from the air injection port OP1 in conjunction with the air ejected from the air injection port OP1. Therefore, it is preferable to appropriately set the relationship between the openings of the third flow control valve 76c and the fourth flow control valve 96 so that the flow rate of air injected from the air injection port OP1 does not exceed the flow rate of the fourth air ejected from the ejection port 49.

[0112] exist Figure 17 In the example described, the openings of the third flow control valve 76c and the fourth flow control valve 96 are preferably set so that the flow rate of air ejected from the air ejection port OP1 is equal to or greater than the third flow rate (more specifically, equal to or greater than the design lower limit flow rate for forming an air curtain). This setting effectively forms an air curtain that prevents foreign matter from entering the machining head 10 from the front end portion thereof.

[0113] exist Figure 17 In the example described above, a portion of the fourth air ejected from the ejection port 49 is recovered through the third recovery flow path 73, thereby reducing the flow rate of the air ejected from the air ejection port OP1. Figure 17 In the example described, by making the opening of the fourth flow control valve 96 sufficiently large, the flow rate of the air ejected from the air ejection port OP1 can be made equal to or greater than the third flow rate while a portion of the fourth air ejected from the ejection port 49 is being recovered via the third recovery flow path 73. By recovering a portion of the fourth air ejected from the ejection port 49 via the third recovery flow path 73, the oil E1 (see, if necessary) is prevented from being Figure 14 ) toward the air injection port OP1. In addition, by injecting air having a flow rate greater than or equal to the third flow rate from the air injection port OP1, foreign matter is prevented from entering the machining head 10 from the front end portion of the machining head 10.

[0114] exist Figure 17 In the example described above, the openings of the third flow control valve 76c and the fourth flow control valve 96 can also be set so that the flow rate of air ejected from the air ejection port OP1 is not less than 1 times and not more than 1.5 times the third flow rate (more specifically, the flow rate at the lower limit designed for forming the air curtain). By setting the flow rate of air ejected from the air ejection port OP1 to not more than 1.5 times the third flow rate, the amount of air ejected from the air ejection port OP1 is prevented from becoming excessive.

[0115] (Mixed fluid supply device 6) exist Figure 17 In the described example, the mixed fluid supply device 6 includes an air source AT (e.g., an air compressor), an oil tank 61 , a pump 62 , a second air supply pipe 63 , a mixer 64 , a supply flow channel 66 , and a mixed fluid supply pipe 68 connecting the mixer 64 and the supply flow channel 66 .

[0116] Air source AT supplies air to mixer 64 via second air supply pipe 63. Hereinafter, the air supplied to mixer 64 via second air supply pipe 63 will be referred to as "fifth air." Pump 62 supplies oil from oil tank 61 to mixer 64. Mixer 64 mixes the fifth air received from air source AT via second air supply pipe 63 with oil received from oil tank 61 to form a mixed fluid containing oil and air. Furthermore, mixer 64 delivers this mixed fluid to supply flow path 66 via mixed fluid supply pipe 68.

[0117] exist Figure 17 In the example described, the mixed fluid supply pipe 68 is arranged outside the housing 4, and the supply flow path 66 is arranged inside the housing 4. The supply flow path 66 supplies a mixed fluid containing oil and air (more specifically, oil and air) to the plurality of bearings 3. Figure 17 In the described example, the supply flow path 66 supplies a mixed fluid containing oil and air to the first bearing 31 a , the second bearing 36 b , and the third bearing 31 c .

[0118] exist Figure 17 In the example described, the air source AT that supplies air to the mixer 64 and the air source AS that supplies air to the multiple ejectors (75a, 75b, 75c) are the same air source. Sharing the air source AT for the mixer 64 and the air source AS for the multiple ejectors (75a, 75b, 75c) allows for space savings. This also reduces manufacturing costs and energy consumption. Alternatively, the air source AT for the mixer 64 and the air source AS for the multiple ejectors (75a, 75b, 75c) may be separate air sources.

[0119] The mixed fluid supply device 6 may also include a fifth flow control valve 67 for adjusting the flow rate of air supplied from the second air supply pipe 63 to the mixer 64. Figure 17 In the example described, the fifth flow control valve 67 is disposed in the second air supply pipe 63. The opening degree of the fifth flow control valve 67 may be set manually or by the controller 8.

[0120] (First air flow passage 77a, second air flow passage 77b, and third air flow passage 77c) The first air flow passage 77a and the second air flow passage 77b have been described in the first embodiment, so repeated description of these flow passages will be omitted. Figure 17 In the example described, the recovery device 7 includes a third air flow path 77c for supplying the third air to the third ejector 75c. Figure 17 In the example described, the third flow control valve 76 c is disposed in the third air flow path 77 c.

[0121] (Main air flow channel 12) exist Figure 17 In the example described, the spindle lubricating device 1 for a machine tool includes a main air flow passage 12 that connects the first air flow passage 77a, the second air flow passage 77b, and the third air flow passage 77c to the air source AS. Figure 17 In the described example, the main air flow path 12 is branched into a plurality of air flow paths including a first air flow path 77 a , a second air flow path 77 b , and a third air flow path 77 c .

[0122] The main air flow passage 12 may be connected to an air supply pipe 91 that supplies air to an air supply flow passage 93 provided in the housing 4. The main air flow passage 12 may be connected to a second air supply pipe 63 that supplies fifth air to the mixer 64.

[0123] (On / off valve 13) exist Figure 18 In the described example, the spindle lubricating device 1 for a machine tool includes a plurality of on-off valves 13 arranged between an air source AS and a plurality of flow control valves ( 76 a , 76 b , 76 c , 67 , 96 ).

[0124] exist Figure 18 In the example described, the recovery device 7 includes the first on-off valve 13a and the second on-off valve 13b. Alternatively, the recovery device 7 may include the third on-off valve 13c.

[0125] The first on-off valve 13a is disposed between the air source AS and the first flow control valve 76a. More specifically, the first on-off valve 13a is disposed in the first air flow passage 77a. The first on-off valve 13a opens and closes the first air flow passage 77a between the air source AS and the first flow control valve 76a.

[0126] The second on-off valve 13b is disposed between the air source AS and the second flow control valve 76b. More specifically, the second on-off valve 13b is disposed in the second air flow passage 77b. The second on-off valve 13b opens and closes the second air flow passage 77b between the air source AS and the second flow control valve 76b.

[0127] The third on-off valve 13c is disposed between the air source AS and the third flow control valve 76c. More specifically, the third on-off valve 13c is disposed in the third air flow passage 77c. The third on-off valve 13c opens and closes the third air flow passage 77c between the air source AS and the third flow control valve 76c.

[0128] exist Figure 18In the example described, the air supply device 9 includes a fourth on-off valve 13d. The fourth on-off valve 13d is positioned between the air source AS and the fourth flow control valve 96. More specifically, the fourth on-off valve 13d is positioned in the air supply pipe 91. The fourth on-off valve 13d opens and closes the flow path of the air supply pipe 91 between the air source AS and the fourth flow control valve 96.

[0129] exist Figure 18 In the example described, the mixed fluid supply device 6 includes a fifth on-off valve 13e. The fifth on-off valve 13e is disposed between the air source AS and the fifth flow control valve 67. More specifically, the fifth on-off valve 13e is disposed in the second air supply pipe 63. The fifth on-off valve 13e opens and closes the flow path of the second air supply pipe 63 between the air source AS and the fifth flow control valve 67.

[0130] (Controller 8) The controller 8 controls the mixed fluid supply device 6 and the recovery device 7. Additionally, the controller 8 may also control the air supply device 9.

[0131] exist Figure 18 In the example described, the controller 8 includes a processor 80, a memory 82 storing programs and data, and a communication circuit 84. Figure 18 In the depicted example, the processor 80 , the memory 82 , and the communication circuit 84 are connected via a bus 88 .

[0132] The controller 8 can be composed of a microcontroller or a computer. The microcontroller integrates the processor 80, memory 82 and communication circuit 84 into an integrated circuit, and the computer is respectively provided with a CPU as the processor 80, a storage unit as the memory 82 and a communication unit as the communication circuit 84.

[0133] The controller 8 controls the air source AS by sending a driving instruction C to the air source AS (eg, an air compressor).

[0134] The controller 8 controls the mixed fluid supply device 6. More specifically, the controller 8 sends a first set of control commands C1 to the mixed fluid supply device 6. Upon receiving the first set of control commands C1, the mixed fluid supply device 6 supplies a first flow rate of the mixed fluid to the plurality of bearings 3. For example, the controller 8 sends the first set of control commands C1 to the fifth on-off valve 13e and the pump 62, thereby using the mixed fluid supply device 6 to supply a mixed fluid containing oil and air to the plurality of bearings 3.

[0135] The controller 8 controls the recovery device 7. The controller 8 sends a second set of control commands C2 to the recovery device 7. Upon receiving the second set of control commands C2, the recovery device 7 recovers the oil-containing fluid. For example, the controller 8 sends the second set of control commands C2 to the first on-off valve 13a, the second on-off valve 13b, and the third on-off valve 13c, thereby using the recovery device 7 to recover the oil-containing fluid. When the opening of the first flow control valve 76a is set to the first opening, the suction force of the first ejector 75a does not cause poor lubrication of the bearings. When the opening of the second flow control valve 76b is set to the second opening, the suction force of the second ejector 75b does not cause poor lubrication of the bearings.

[0136] The controller 8 can also control the air supply device 9 to eject air from the air ejection port OP1. The controller 8 sends a third set of control commands C3 to the air supply device 9. Upon receiving the third set of control commands C3, the air supply device 9 supplies the fourth air to the ejection port 49 formed in the housing 4. For example, the controller 8 sends a control command C3 to the fourth on-off valve 13d, thereby using the air supply device 9 to supply the fourth air to the ejection port 49. A portion of the fourth air supplied to the ejection port 49 is ejected from the air ejection port OP1, and a portion of the fourth air supplied to the ejection port 49 is recovered by the recovery device 7 via the third recovery flow path 73.

[0137] By appropriately setting the opening of the third flow control valve 76c and the opening of the fourth flow control valve 96, (1) the third oil-containing fluid containing oil that has not been recovered by the first recovery channel 71 but has passed through the first bearing 31a is recovered via the third recovery channel 73, (2) the oil is prevented from or suppressed from mixing into the air injected from the air injection port OP1, and (3) an air curtain is appropriately formed by the air injected from the air injection port OP1.

[0138] (First Rotation Driving Device 5) exist Figure 17 In the example described, the spindle lubricating device 1 for a machine tool includes a first rotation drive device 5 that rotates a rotating body 2 (more specifically, a rotating shaft 20 ) about a first axis AX1 . The first rotation drive device 5 may also be a first motor. Figure 17 In the example described, the first rotation drive device 5 (more specifically, the first motor) includes a stator 51 and a rotor 53. In this case, when current is supplied to the stator 51, the rotor 53 rotates around the first axis AX1 by electromagnetic action. Figure 17 In the described example, the stator 51 is fixed to the housing 4 , and the rotor 53 is fixed to the rotating body 2 (more specifically, the rotating shaft 20 ).

[0139] exist Figure 17In the example described, the rotor 53 is arranged in the intermediate portion 23 of the rotating shaft 20. The rotor 53 is arranged on the second direction DR2 side relative to the first bearing 31a and on the first direction DR1 side relative to the second bearing 36b.

[0140] exist Figure 17 In the example described above, the first rotational drive device 5 is disposed inside the housing 4. Alternatively, the first rotational drive device 5 may be disposed outside the housing 4. For example, the first rotational drive device 5 disposed outside the housing 4 may be configured to rotate the rotating body 2 via any power transmission mechanism (e.g., gears, a transmission belt, etc.).

[0141] (Processing head 10) The spindle lubrication device 1 of the machine tool includes a machining head 10. Figure 19 In the example described, the machining head 10 includes: (1) a rotating body 2 for holding a tool T; (2) a plurality of bearings 3, including a first bearing 31a and a second bearing 36b; (3) a housing 4, which supports the rotating body 2 by means of the plurality of bearings 3 so as to be rotatable about a first axis AX1; and (4) a first rotation drive device 5 for rotating the rotating body 2 about the first axis AX1.

[0142] (rotating body 2) exist Figure 19 In the example described, the rotating body 2 has a rear end portion 22 and a front end portion 24 for holding a tool T. More specifically, the rotating body 2 (more specifically, the rotating shaft 20) has a rotating shaft body 21, a mounting portion 28 for mounting the tool T, and a rod-shaped member 291 connected to the mounting portion 28. The rod-shaped member 291 is arranged inside the rotating shaft body 21. Figure 19 In the example described, when the mounting portion drive device 14 of the machining head 10 presses the rod-shaped member 291 in the first direction DR1, the rod-shaped member 291 and the mounting portion 28 move relative to the rotating shaft body 21 in the first direction DR1. In this state, the tool T mounted on the mounting portion 28 can be replaced with another tool. After the tool is replaced, the biasing member 293 (e.g., a disc spring) disposed on the rotating shaft 20 presses the rod-shaped member 291 in the second direction DR2. This causes the rod-shaped member 291 and the mounting portion 28 to move relative to the rotating shaft body 21 in the second direction DR2.

[0143] exist Figure 20 In the example described, the rotating body 2 (more specifically, the rotating shaft body 21 ) has an inner peripheral surface 21 n that contacts the tool holder HD. The inner peripheral surface 21 n is, for example, a tapered surface whose diameter increases as it goes toward the first direction DR1 .

[0144] exist Figure 21In the described example, the rotating body 2 (more specifically, the rotating shaft 20 ) includes the first portion 25 , the second portion 26 , and the stepped surface 25 a .

[0145] The first portion 25 supports the inner ring 32a of the first bearing 31a. The first portion 25 has a first outer peripheral surface 25u.

[0146] The second portion 26 has a second outer peripheral surface 26u having a smaller diameter than the first outer peripheral surface 25u. In other words, the diameter of the second outer peripheral surface 26u of the second portion 26 is smaller than the diameter of the first outer peripheral surface 25u of the first portion 25. The second portion 26 is arranged further to the first direction DR1 than the first portion 25.

[0147] The step surface 25 a connects the first outer peripheral surface 25 u of the first portion 25 and the second outer peripheral surface 26 u of the second portion 26 .

[0148] exist Figure 21 In the example described, the first portion 25 of the rotating body 2 and the second portion 26 of the rotating body 2 are each formed from a portion of the rotating shaft body 21. Alternatively, at least a portion of the first portion 25 of the rotating body 2 and the second portion 26 of the rotating body 2 may be formed from a component other than the rotating shaft body 21 (e.g., an inner ring retainer that is separate from the rotating shaft body 21).

[0149] (Shell 4) exist Figure 19 In the described example, the housing 4 includes a front end portion 4 a , a rear end portion 4 b , and an intermediate portion 4 c between the front end portion 4 a and the rear end portion 4 b .

[0150] like Figure 20 As shown in the example, the front end portion 4a of the housing 4 supports the outer ring of the front bearing 31. Figure 20 In the example described, the front end portion 4 a of the housing 4 supports the outer ring 33 a of the first bearing 31 a and the outer ring 33 c of the third bearing 31 c .

[0151] The housing 4 may also include an outwardly projecting flange 47. Figure 20 In the example described above, the flange 47 is disposed on the front end portion 4a of the housing 4. Alternatively, the flange 47 may be provided with the outlet port 71p of the first recovery flow path 71. Figure 20 In the example described above, the first pipe 74a is connected to the outlet port 71p. Alternatively, the outlet port 73p of the third recovery flow path 73 may be provided on the flange 47. Figure 20 In the example described above, the third duct 74c is connected to the outlet port 73p. Alternatively, the inlet port 93p of the air supply passage 93 may be provided on the flange 47. Figure 20In the example described, the air supply pipe 91 is connected to the inlet port 93p. Figure 20 In the example described, the housing 4 is provided with a supply flow path 66. Figure 20 In the described example, the supply flow path 66 supplies a mixed fluid containing oil and air (more specifically, oil-air) to the front bearing including the first bearing 31 a and the third bearing 31 c .

[0152] The rear end side portion 4b of the housing 4 supports the outer ring of the rear bearing 36. Figure 19 In the example described, the rear end portion 4b of the housing 4 supports the outer ring 37b of the second bearing 36b. The rear end portion 4b may include an end plate 40b disposed at the end of the housing 4 on the second direction DR2 side.

[0153] exist Figure 19 In the example described, the intermediate portion 4 c of the housing 4 has a cylindrical side wall 40 c . The intermediate portion 4 c of the housing 4 (more specifically, the cylindrical side wall 40 c ) can also support the stator 51 .

[0154] exist Figure 21 In the described example, the housing 4 (more specifically, the front end portion 4 a of the housing 4 ) includes a third portion 41 and a fourth portion 42 .

[0155] The third portion 41 supports the outer ring 33a of the first bearing 31a. Figure 22 As shown in the example, a first gap G1 is formed between the first portion 25 of the rotating body 2 and the third portion 41 of the housing. Figure 22 In the example described, the oil E that has passed through the first bearing 31a exists in the first gap G1. In the first gap G1, the oil E may exist in the form of oil gas, oil mist, or liquid oil. Figure 22 In the example described, the first gap G1 is linear in the longitudinal section including the first axis AX1. Alternatively, the first gap G1 may also have a maze shape in the longitudinal section including the first axis AX1. Alternatively or additionally, Figure 23 As illustrated, a notch CT may be formed in a portion of the surface defining the first gap G1 . The notch CT may be formed in the first outer peripheral surface 25 u of the rotating body 2 or in the surface of the third portion 41 of the housing 4 .

[0156] The fourth portion 42 defines an annular accommodation space SP that receives the oil E from the first gap G1. Within the annular accommodation space SP, the oil E can exist in the form of oil vapor, oil mist, or liquid oil. The shape of the annular accommodation space SP is not limited and can be any shape.

[0157] exist Figure 23 In the example described, the first gap G1 and the annular accommodating space SP are arranged on a straight line LN parallel to the first axis AX1. In this case, the oil E in the first gap G1 is smoothly guided to the annular accommodating space SP.

[0158] exist Figure 23 In the example described, the fourth portion 42 includes the opening 45 that guides the oil E from the annular accommodation space SP to the third recovery flow path 73 .

[0159] exist Figure 24 In the example described, a second gap G2 in fluid communication with the first gap G1 is formed between the housing 4 and the stepped surface 25a of the rotating body 2. Furthermore, a third gap G3 in fluid communication with the second gap G2 is formed between the housing 4 and the second outer peripheral surface 26u of the rotating body 2.

[0160] Consider a path from the first gap G1 to the outside of the machining head 10. This path may cause oil leakage. Figure 24 In the example described, the second gap G2 between the housing 4 and the stepped surface 25a exists in the path from the first gap G1 to the outside of the machining head 10. Therefore, the existence of the second gap G2 suppresses oil leakage to the outside of the machining head 10 through the above path.

[0161] exist Figure 24 In the example described, the extending direction of the first gap G1 is different from the extending direction of the second gap G2. Therefore, the oil in the first gap G1 is prevented from flowing into the second gap G2. For example, the oil moving downward from the first gap G1 is prevented from entering the second gap G2. Figure 24 In the described example, the first gap G1 extends in the first direction DR1 , and the second gap G2 extends in the radial direction DR3 (more specifically, a direction perpendicular to and toward the first axis AX1 ).

[0162] exist Figure 24 In the example described, the third gap G3 is connected to the second gap G2 via the corner CN. In addition, the extending direction of the third gap G3 is different from the extending direction of the second gap G2. Figure 24 In the described example, the third gap G3 extends in the first direction DR1 , and the second gap G2 extends in the radial direction DR3 (more specifically, a direction perpendicular to and toward the first axis AX1 ).

[0163] (Annular protrusion 44) exist Figure 25 In the example described, the fourth portion 42 includes a base portion 43 connected to the third portion 41 and an annular protrusion 44 protruding from the base portion 43 toward the first axis AX1. Figure 25 In the figure, in order to make the shape of the annular protrusion 44 easier to understand, the annular protrusion 44 is shaded with dots.

[0164] like Figure 24 As illustrated, the annular protrusion 44 has a first surface 44 a facing the stepped surface 25 a and a second surface 44 b facing the outer peripheral surface of the second portion 26 of the rotating body 2 (in other words, the second outer peripheral surface 26 u ).

[0165] Alternatively, the annular protrusion 44 may include an annular protrusion 441 that projects away from the first axis AX1. The annular protrusion 441 faces both the stepped surface 25a and the annular accommodation space SP. When the fourth portion 42 (more specifically, the annular protrusion 44 of the fourth portion 42) includes the annular protrusion 441 that projects away from the first axis AX1, oil E entering the annular accommodation space SP is less likely to flow back toward the second gap G2. Consequently, oil leakage from the gap between the rotating body 2 and the front end 46 of the housing 4 to the outside of the machining head 10 is effectively suppressed.

[0166] exist Figure 25 In the example described, the housing 4 includes a first component CP1 (more specifically, an annular first component CP1) that includes the annular protrusion 441, and a second component CP2 (more specifically, an annular second component CP2) that supports the first component CP1. When the first component CP1 that includes the annular protrusion 441 is a separate component from the second component CP2, the degree of freedom in designing the internal shape of the housing 4 (for example, the degree of freedom in the shape of the annular accommodation space SP) is increased.

[0167] exist Figure 25 In the described example, the first component CP1 and the second component CP2 each have a portion facing the annular accommodation space SP. In a longitudinal cross-section passing through the first axis AX1, the first component CP1 may have a substantially L-shaped shape or another shape. The second component CP2 may also be an end plate disposed at the end of the housing 4 on the first direction DR1 side.

[0168] exist Figure 24 In the described example, the annular protrusion 44 has a first wall 440a that defines the bottom surface of the annular accommodating space SP (in other words, the end surface of the annular accommodating space SP on the first direction DR1 side) and a second wall 440b that defines the second surface 44b, which faces the second outer peripheral surface 26u of the rotating body 2.

[0169] exist Figure 24In the example described, the first wall 440a is an annular wall connected to the base 43 of the fourth portion 42 and extending from the base 43 in the radially inward direction DR3. Furthermore, the second wall 440b is an annular wall connected to the inner edge of the first wall 440a and extending from the inner edge in the second direction DR2. Furthermore, the annular protrusion 441 is connected to the end of the second wall 440b on the side in the second direction DR2 and protrudes from this end in the radially outward direction DR4.

[0170] The annular protrusion 44 may also have a first annular groove V1. Figure 24 In the example described, the first annular groove V1 is a groove facing the annular accommodation space SP and recessed in the radially inward direction DR3 . The first annular groove V1 prevents or suppresses the oil in the annular accommodation space SP from flowing back to the second gap G2 .

[0171] exist Figure 24 In the example described, the fourth portion 42 of the housing 4 has a second annular groove V2. The second annular groove V2 is a groove facing the annular accommodation space SP and recessed in the radially outward direction DR4 (in other words, in a direction away from the first axis AX1). Figure 24 In the described example, the second annular groove V2 is arranged in the fourth portion 42 of the housing 4 so as to face the first annular groove V1 .

[0172] exist Figure 26 In order to easily understand the shapes of the first annular groove V1 and the second annular groove V2, the portions other than the first annular groove V1 and the second annular groove V2 are indicated by dotted lines, and the first annular groove V1 and the second annular groove V2 are indicated by solid lines. Figure 26 In the example described, oil can be contained in both the first annular groove V1 and the second annular groove V2. In this case, the annular accommodating space SP includes the space defined by the first annular groove V1 and the space defined by the second annular groove V2, thereby increasing the overall volume of the annular accommodating space SP.

[0173] exist Figure 26 In the example described, the annular protrusion 44 has a third surface 44f constituting a portion of the end surface 4f on the first direction DR1 side of the housing 4. The third surface 44f is a surface on the first direction DR1 side of the first wall 440a.

[0174] (Air injection port OP1 and air injection port 49) exist Figure 24 In the described example, the air injection port OP1 communicating with the third gap G3 is formed between the front end portion 46 of the housing 4 and the rotating body 2 .

[0175] Furthermore, the housing 4 is provided with an air supply flow path 93 through which the fourth air supplied from the air supply pipe 91 flows, and an air outlet 49 through which the fourth air is ejected. The air outlet 49 ejects the fourth air received from the air supply flow path 93 toward the third gap G3 in such a manner as to form a first air flow from the third gap G3 toward the second gap G2 and a second air flow from the third gap G3 toward the air ejection port OP1.

[0176] The fourth air ejected from the air ejection port OP1 prevents foreign matter such as chips from entering the machining head 10 through the third gap G3 and the like. More specifically, the fourth air ejected from the air ejection port OP1 forms an air curtain AC around the tool T or the tool holder HD. This air curtain prevents foreign matter such as chips from entering the machining head 10 through the third gap G3 and the like.

[0177] exist Figure 24 In the example described, the fourth air flowing from the third gap G3 toward the second gap G2 prevents the oil E from entering the second gap G2 from the first gap G1 or the annular accommodation space SP. Furthermore, the fourth air flowing from the third gap G3 toward the second gap G2 pushes the oil that has entered the second gap G2 back toward the annular accommodation space SP.

[0178] At least a portion of the fourth air flowing from the third gap G3 toward the second gap G2 reaches the annular accommodating space SP. The air reaching the annular accommodating space SP is recovered through the third recovery flow path 73.

[0179] The air (or air containing a small amount of oil) that is not recovered by the first recovery flow channel 71, the second recovery flow channel 72, and the third recovery flow channel 73 is discharged from the gap of the machining head 10 to the outside of the machining head 10 (see Figure 19 dashed arrow in the figure).

[0180] (Third embodiment) Reference Figures 1 to 31 , a machine tool 100 according to a third embodiment will be described. Figure 27 It is a schematic perspective view schematically showing an example of a machine tool 100 according to the third embodiment. Figure 28 It is a schematic perspective view schematically showing another example of the machine tool 100 in the third embodiment. Figure 29 Schematically illustrates a case where the control device 140 can control a plurality of control target devices. Figure 30 This is a diagram for explaining an example of the arrangement of the recovery container 792. Figure 31 This is a diagram for explaining another example of the arrangement of the recovery container 792.

[0181] The third embodiment will be described primarily with respect to the differences from the first and second embodiments. Furthermore, in the third embodiment, repeated descriptions of matters already described in the first or second embodiment will be omitted. Therefore, even if not explicitly described in the third embodiment, matters already described in the first or second embodiment can of course be applied to the third embodiment.

[0182] like Figure 27 and Figure 29 As illustrated, the machine tool 100 in the third embodiment includes a machining head 10, a mixed fluid supply device 6, a recovery device 7, a workpiece support device 110 that supports the workpiece W, a moving device 120 that moves the machining head 10 relative to the workpiece support device 110, and a control device 140.

[0183] The machining head 10 , the mixed fluid supply device 6 , and the recovery device 7 have already been described in the first embodiment or the second embodiment, and therefore, repeated description of their structures will be omitted.

[0184] (Workpiece support device 110) exist Figure 27 In the example described, the workpiece support device 110 includes a support member 111 (more specifically, a table 111a) that supports the workpiece W, and a second rotation drive device 112 that rotates the support member 111 (more specifically, the table 111a) about a second axis AX2. The workpiece support device 110 may also include a tilting device 113 that tilts the table 111a about an axis AX3 that is perpendicular to the second axis AX2.

[0185] Alternatively, if Figure 28 As illustrated, the workpiece support device 110 may include a chuck 111 b for holding the workpiece W and a second rotation drive device 112 for rotating the chuck 111 b around the second axis AX2.

[0186] (Mobile device 120) The moving device 120 moves the machining head 10 relative to the workpiece support device 110. The moving device 120 may also be a device that can move the machining head 10 in three dimensions. The moving device 120 may also be capable of moving the machining head 10 along a Z-axis parallel to the vertical direction. The moving device 120 may also be capable of moving the machining head 10 along an X-axis parallel to the horizontal direction. In addition, the moving device 120 may also be capable of moving the machining head 10 along a Y-axis perpendicular to both the X-axis and the Z-axis. Figure 27 and Figure 28 In the described example, the machining head 10 is supported by the base 130 via the moving device 120 .

[0187] (Control device 140) The control device 140 controls at least the first rotation driving device 5, the mixed fluid supply device 6, and the moving device 120. Additionally, the control device 140 may also control the recovery device 7.

[0188] like Figure 29 As shown, control device 140 includes a hardware processor 141 (hereinafter referred to as "processor 141"), memory 142, communication circuit 144, and input device 146 (e.g., display 146a with a touch panel). Processor 141, memory 142, communication circuit 144, and input device 146 are interconnected via bus 148.

[0189] The memory 142 stores data 142a required for machining a workpiece and a program 142b for operating the various components of the machine tool 100. The memory 142 is a storage medium readable by the processor 141 of the control device 140. The memory 142 may be, for example, a nonvolatile or volatile semiconductor memory such as RAM, ROM, or flash memory, a magnetic disk, or other memory formats.

[0190] The input device 146 is not limited to the display 146a with a touch panel. For example, the control device 140 may include an input device 146 such as a button, switch, joystick, pointing device, or keyboard, as well as a display for displaying data or other information input to the input device 146. Furthermore, the memory 142 may be distributed across multiple locations. For example, a portion of the memory 142 may be stored in cloud storage.

[0191] Alternatively, a plurality of computers may cooperate to function as the control device 140. Figure 29 In the example described, the control device 140 includes a main control device 140a and the aforementioned controller 8. In other words, the main control device 140a and the controller 8 cooperate to function as the control device 140. The controller 8 operates based on instructions received from the main control device 140a. Furthermore, if the functions of the controller 8 described in the first or second embodiment are integrated into the main control device 140a, the controller 8 is omitted. In other words, the main control device 140a itself functions as the controller 8.

[0192] exist Figure 29 In the example described, if the control device 14 sends a first set of control instructions C1 to the mixed fluid supply device 6, the mixed fluid supply device 6, upon receiving the first set of control instructions C1, supplies a first flow rate of the mixed fluid to the plurality of bearings 3. In this manner, a mixed fluid containing oil and air is supplied to the plurality of bearings 3.

[0193] exist Figure 29In the described example, if the control device 140 sends the second set of control instructions C2 to the recovery device 7 , the recovery device 7 receiving the second set of control instructions C2 recovers the oil-containing fluid.

[0194] For example, the recovery device 7, receiving the second set of control commands C2, supplies the first air to the first ejector 75a. The first air generates a negative pressure in the first conduit 74a, which in turn draws the first oil-containing fluid from the first recovery flow path 71 via the first conduit 74a. When the opening of the first flow control valve 76a is set to the first opening, the suction force of the first ejector 75a does not cause poor lubrication of the bearing.

[0195] For example, the recovery device 7, receiving the second set of control commands C2, supplies the second air to the second ejector 75b. The second air generates a negative pressure in the second conduit 74b, which in turn draws the second oil-containing fluid from the second recovery flow path 72 via the second conduit 74b. When the second flow control valve 76b is set to the second opening, the suction force of the second ejector 75b does not cause poor lubrication of the bearing.

[0196] For example, the recovery device 7 receiving the second set of control instructions C2 supplies third air to the third ejector 75c. The third air generates negative pressure in the third pipe 74c, which in turn draws the third oil-containing fluid from the third recovery flow path 73 via the third pipe 74c.

[0197] exist Figure 29 In the described example, when the control device 140 transmits the control command C3 to the air supply device 9 , the air supply device 9 receiving the control command C3 supplies the fourth air to the discharge port 49 formed in the housing 4 .

[0198] Part of the fourth air ejected from the ejection port 49 is ejected from the air ejection port OP1 . The air ejected from the air ejection port OP1 forms an air curtain. Part of the fourth air ejected from the ejection port 49 is recovered by the recovery device 7 via the third recovery flow path 73 .

[0199] exist Figure 29 In the example described, when the control device 140 sends the first movement command J1 to the moving device 120, the moving device 120 moves the machining head 10 relative to the workpiece support 110. In this way, the tool T held by the rotating body 2 can be moved toward the workpiece W.

[0200] exist Figure 29In the example described, when the control device 140 sends the first rotation command R1 to the first rotation drive device 5, the first rotation drive device 5 rotates the rotating body 2 about the first axis AX1. In this way, the tool T held by the rotating body 2 can machine the workpiece W.

[0201] The control device 140 may be capable of controlling the second rotation drive device 112. For example, if the control device 140 sends a second rotation command R2 to the second rotation drive device 112, the second rotation drive device 112 receives the second rotation command R2 and rotates the support 111 supporting the workpiece W about the second axis AX2.

[0202] The processor 141 of the control device 140 executes the program 142b stored in the memory 142, thereby generating a control command. Furthermore, the communication circuit 144 transmits this control command to the controlled devices (more specifically, the first rotational drive device 5, the moving device 120, the mixed fluid supply device 6, the recovery device 7, the air supply device 9, and the second rotational drive device 112). Thus, by executing the program 142b on the processor 141, the control device 140 can control the first rotational drive device 5, the moving device 120, the mixed fluid supply device 6, the recovery device 7, the air supply device 9, and the second rotational drive device 112.

[0203] (Configuration of Recovery Container 792) exist Figure 30 In the described example, the machine tool 100 includes: an outer wall 171 that surrounds the workpiece support device 110 and the machining head 10 when viewed from above; an opening 173 formed in the outer wall 171 for allowing the workpiece carried into the workpiece support device 110 to pass through; and a door 175 that opens and closes the opening 173.

[0204] exist Figure 30 In the example described, the recovery container 792 is arranged at a position that can be reached by the operator's hand from outside the machine tool through the opening 173. In other words, the recovery container 792 is arranged near the opening 173. In this case, the operator can easily remove the drain oil recovered in the recovery container 792 from the machine tool 100. Alternatively, Figure 31 As illustrated, the recovery container 792 may be arranged outside the outer wall 171 .

[0205] When the recovery container 792 is located near the opening 173 or further outward from the outer wall 171, the pipe from the machining head 10 to the recovery container 792 becomes longer. If the pipe becomes longer, the pressure loss of the fluid flowing through the pipe becomes greater, making it more difficult to optimize lubrication for each of the multiple bearings. In the third embodiment, the suction force acting on each ejector can be set individually. Therefore, even if the pipe to the recovery container 792 is long, lubrication can be optimized for each of the multiple bearings by appropriately setting each suction force. In particular, by setting the opening of each flow control valve (75a, 75b, ...) in consideration of the first and second conditions CD1 and CD2 (or the third and fourth conditions CD3 and CD4), the suction force acting on each ejector can be easily and appropriately set.

[0206] (How to use the machine tool) Reference Figures 1 to 32 , the method of using the machine tool in the implementation method is explained. Figure 32 This is a flowchart showing an example of a method of using a machine tool in the embodiment.

[0207] The machine tool used in the method of using a machine tool is, for example, machine tool 100 in the third embodiment. Machine tool 100 and its components have been described in the first to third embodiments, and therefore, repeated description thereof will be omitted.

[0208] In the first step ST1, the first discharge flow rate and the second discharge flow rate are derived. The first step ST1 is a discharge flow rate deriving step.

[0209] The discharge flow rate derivation step (first step ST1) is included in the second condition CD2 (see Figure 5 or Figure 9 ) is defined as a first discharge flow rate, and the first discharge flow rate is derived by measurement or simulation.

[0210] The discharge flow rate derivation step (first step ST1) is included in the second condition CD2 (see Figure 5 or Figure 9 ) is defined as a second discharge flow rate of the second oil-containing fluid discharged from the second recovery flow channel 72 to the outside of the second recovery flow channel 72 (for example, outside the housing 4), the second discharge flow rate is derived by measurement or simulation.

[0211] In addition, when the machine tool 100 includes the third recovery flow path 73, the air supply flow path 93, and the air injection port OP1, the exhaust flow rate derivation step (first step ST1) may also be included in the fourth condition CD4 (see Figure 16 In addition, when the flow rate of the first oil-containing fluid discharged from the first recovery flow channel 71 to the outside of the first recovery flow channel 71 (for example, outside the housing 4) is defined as the first discharge flow rate under the fourth condition CD4 (one embodiment of the second condition CD2), the first discharge flow rate is derived by measurement or simulation. In addition, the discharge flow rate deriving step (first step ST1) may also be included in the fourth condition CD4 (see Figure 16 ) is defined as a second discharge flow rate of the second oil-containing fluid discharged from the second recovery flow channel 72 to the outside of the second recovery flow channel 72 (for example, outside the housing 4), the second discharge flow rate is derived by measurement or simulation.

[0212] In the second step ST2, the first recovery flow rate and the second recovery flow rate are derived. The second step ST2 is a recovery flow rate deriving step.

[0213] The recovery flow rate derivation step (second step ST2) is included in the first condition CD1 (see Figure 4 or Figure 8 ) When the flow rate of the first oil-containing fluid flowing in the first pipe 74a is defined as the first recovery flow rate, the first recovery flow rate is derived through measurement or simulation.

[0214] The recovery flow rate derivation step (second step ST2) is included in the first condition CD1 (see Figure 4 or Figure 8 ) When the flow rate of the second oil-containing fluid flowing in the second pipe 74b is defined as the second recovery flow rate, the second recovery flow rate is derived through measurement or simulation.

[0215] In addition, when the machine tool 100 includes the third recovery flow path 73, the air supply flow path 93, and the air injection port OP1, the recovery flow rate derivation step (second step ST2) may also be included in the third condition CD3 (see Figure 15 In addition, when the flow rate of the first oil-containing fluid flowing in the first pipe 74a is defined as the first recovery flow rate under the third condition CD3 (one embodiment of the first condition CD1), the first recovery flow rate is derived by measurement or simulation. In addition, the recovery flow rate derivation step (second step ST2) may also be included in the third condition CD3 (see Figure 15 ) When the flow rate of the second oil-containing fluid flowing in the second pipe 74b is defined as the second recovery flow rate, the second recovery flow rate is derived through measurement or simulation.

[0216] In the third step ST3, the opening degree of the first flow control valve 76a and the opening degree of the second flow control valve 76b are derived. The third step ST3 is an opening degree deriving step.

[0217] The opening derivation step (third step ST3) includes deriving a first opening of the first flow control valve 76a such that the ratio of the first recovery flow rate to the first discharge flow rate falls within a predetermined range. For example, the opening derivation step includes deriving the first opening of the first flow control valve 76a such that the first recovery flow rate falls within a range of 1 to 1.5 times the first discharge flow rate (more preferably, the first recovery flow rate falls within a range of 1 to 1.2 times the first discharge flow rate). Alternatively, a correlation between the opening of the first flow control valve 76a and the first recovery flow rate can be determined, and the first opening can be derived based on this correlation. Alternatively, the first opening can be derived through trial and error.

[0218] The opening derivation step (third step ST3) includes deriving the second opening of the second flow control valve 76b so that the ratio of the second recovery flow rate to the second discharge flow rate falls within a predetermined range. For example, the opening derivation step includes deriving the second opening of the second flow control valve 76b so that the second recovery flow rate falls within a range of 1 to 1.5 times the second discharge flow rate (more preferably, the second recovery flow rate falls within a range of 1 to 1.2 times the second discharge flow rate). Alternatively, a correlation between the opening of the second flow control valve 76b and the second recovery flow rate can be determined, and the second opening can be derived based on this correlation. Alternatively, the second opening can be derived through trial and error.

[0219] In addition, when the machine tool 100 includes the third recovery flow path 73, the air supply flow path 93 and the air ejection port OP1, the opening derivation step (third step ST3) may also include derivation of the air ejection port 49 (see Figure 14 ) is larger than the flow rate of the fourth air ejected from the air ejection port OP1 (refer to Figure 14 ) The opening degree of the third flow control valve 76c (hereinafter referred to as the “third opening degree”) and the opening degree of the fourth flow control valve 96 (hereinafter referred to as the “fourth opening degree”) that control the flow rate of the injected air.

[0220] More specifically, the opening leading-out process (third step ST3) may also include leading-out (1) so that the opening from the discharge port 49 (refer to Figure 14 ) is larger than the flow rate of the fourth air ejected from the air ejection port OP1 (refer to Figure 14) the flow rate of the air injected, and (2) the third opening of the third flow control valve 76c and the fourth opening of the fourth flow control valve 96 so that the flow rate of the air injected from the air injection port OP1 is greater than the above-mentioned third flow rate (more specifically, greater than the flow rate of the design lower limit for forming the air curtain).

[0221] For example, steps 1 through 3 ST3 are performed before the spindle lubrication device 1 (or machine tool 100) is shipped to a customer. More specifically, steps 1 through 3 ST3 are performed before the machine tool 100 is installed at the customer's factory. Furthermore, steps 4 through 6 ST6, described below, are performed after the machine tool 100 is installed at the customer's factory. More specifically, steps 4 through 6 ST6, described below, are performed while the machine tool 100 is machining a workpiece.

[0222] In the fourth step ST4, a mixed fluid containing oil and air is supplied to the plurality of bearings 3. The fourth step ST4 is a mixed fluid supplying step. The mixed fluid supplying step is performed using the mixed fluid supplying device 6.

[0223] In the fifth step ST5, the recovery device 7 is activated. The fifth step ST5 is the recovery device activation step. The recovery device activation step includes activating the recovery device 7 with the first flow control valve 76a set to the first opening and the second flow control valve 76b set to the second opening. Furthermore, if the machine tool 100 includes a third recovery flow channel 73, the recovery device activation step includes recovering the third oil-containing fluid, which has not been recovered by the first recovery flow channel 71 but has passed through the first bearing 31a, via the third recovery flow channel 73. More specifically, the recovery device activation step may also include activating the recovery device 7 with the third flow control valve 76c set to the third opening.

[0224] In the sixth step ST6 , the workpiece is machined. The sixth step ST6 is a workpiece machining step. In the workpiece machining step, the workpiece W is machined by the tool T held by the rotating body 2 and rotating around the first axis AX1 .

[0225] Steps 4 to 6 ST6 are executed in parallel. More specifically, during the workpiece machining process, the recovery device 7 operates while the mixed fluid supply device 6 is supplying a mixed fluid containing oil and air to the plurality of bearings 3, and the opening of the first flow control valve 76a is set to the first opening and the opening of the second flow control valve 76b is set to the second opening.

[0226] When the recovery device 7 is operating with the first flow control valve 76a set to the first opening, the first oil-containing fluid is properly recovered via the first recovery flow path 71 and the first pipe 74a. Furthermore, the suction force of the first ejector 75a does not cause poor lubrication of the bearings. Furthermore, the first oil-containing fluid, having passed through the first ejector 75a, is preferably delivered to the exhaust gas purifier 791 via the exhaust pipe 78.

[0227] When the recovery device 7 is operating with the second flow control valve 76b set to the second opening, the second oil-containing fluid is properly recovered via the second recovery flow path 72 and the second pipe 74b. Furthermore, the suction force of the second ejector 75b does not cause poor lubrication of the bearings. Furthermore, the second oil-containing fluid, after passing through the second ejector 75b, is preferably delivered to the exhaust gas purifier 791 via the exhaust pipe 78.

[0228] In addition, in the case where the machine tool 100 includes an air supply flow channel 93 and an air injection port OP1, the workpiece processing process (sixth step ST6) is preferably performed under the following conditions: (1) the fourth air is supplied to the air supply flow channel 93 provided in the shell, (2) a part of the fourth air is injected as an air curtain from the air injection port OP1 formed between the rotating body 2 and the front end portion 46 of the shell 4, and (3) the flow rate of the fourth air supplied to the air supply flow channel 93 is greater than the flow rate of the air injected from the air injection port OP1.

[0229] More specifically, it is preferred that the recovery device 7 is operated in a state where the opening of the third flow control valve 76c is set to the third opening, and the air supply device 9 is operated in a state where the opening of the fourth flow control valve 96 is set to the fourth opening. When the recovery device 7 is operated in a state where the opening of the third flow control valve 76c is set to the third opening, when the workpiece processing step (sixth step ST6) is performed, the third oil-containing fluid containing oil that has not been recovered by the first recovery flow path 71 but has passed through the first bearing 31a is recovered via the third recovery flow path 73. In addition, when the recovery device 7 is operated in a state where the opening of the third flow control valve 76c is set to the third opening, and the air supply device 9 is operated in a state where the opening of the fourth flow control valve 96 is set to the fourth opening, (1) oil is prevented or suppressed from mixing into the air ejected from the air ejection port OP1, and (2) an air curtain is appropriately formed using the air ejected from the air ejection port OP1.

[0230] The present invention is not limited to the above-described embodiments or variations. It is apparent that the embodiments or variations may be appropriately modified or altered within the scope of the technical concept of the present invention. Furthermore, the various techniques employed in the embodiments or variations may also be applied to other embodiments or variations, as long as no technical contradictions arise. Furthermore, any additional structures in the embodiments or variations may be appropriately omitted.

[0231] For example, in Figure 27 In the example described, the machine tool 100 is a vertical machining center. Alternatively, the machine tool 100 in the embodiment may be a horizontal machining center. Furthermore, the machine tool 100 may be a multi-processor capable of performing machining other than cutting. Description of Reference Numerals

[0232] 1, 1A, 1A', 1B spindle lubrication device, 2 rotating body, 3 bearing, 4 housing, 4a front end portion of the housing, 4b rear end portion of the housing, 4c middle portion of the housing, 4f end surface of the housing, 5 first rotary drive device, 6 mixed fluid supply device, 7 recovery device, 8 controller, 9 air supply device, 10 machining head, 11a first flow meter, 11b second flow meter, 12 main air flow channel, 13 on-off valve, 13a first on-off valve, 13b second on-off valve, 13c third on-off valve, 13d fourth on-off valve, 13e fifth on-off valve, 14 mounting portion drive device, 20 rotating shaft, 21 rotating shaft main body, 21n inner circumferential surface of the rotating body, 22 rear end portion of the rotating body, 23 middle portion of the rotating body, 24 front end portion of the rotating body, 25 first portion of the rotating body, 25a step surface of the rotating body, 25u First outer peripheral surface, 26 Second portion of the rotating body, 26u Second outer peripheral surface, 28 Mounting portion, 31 Front bearing, 31a First bearing, 31c Third bearing, 32a, 32c Inner ring, 33a, 33c Outer ring, 34a, 34c Rolling element, 36 Rear bearing, 36b Second bearing, 37b Outer ring, 40b End plate of the housing, 40c Side wall of the housing, 41 Third portion of the housing, 42 Fourth portion of the housing, 43 Base of the fourth portion, 44 Annular protrusion, 44a First surface, 44b Second surface, 44f Third surface, 45 Opening, 46 Front end portion of the housing, 47 Flange, 49 Spray port, 51 Stator, 53 Rotor, 61 Oil tank, 62 Pump, 63 Second air supply pipe, 64 Mixer, 66 Supply flow path, 67 Fifth flow control valve, 68 Mixed fluid supply pipe, 71 first recovery flow channel, 71p outlet port, 72 second recovery flow channel, 73 third recovery flow channel, 73p outlet port, 74 pipeline, 74a first pipeline, 74b second pipeline, 74c third pipeline, 75 ejector, 75' negative pressure generating device, 75a first ejector, 75b second ejector, 75c third ejector, 76a first flow control valve, 76b second flow control valve, 76c third flow control valve, 77a first air flow channel, 77b second air flow channel, 77c third air flow channel, 78 exhaust pipe, 80 processor, 82 memory, 84 communication circuit, 88 bus, 91 air supply pipe, 93 air supply flow channel, 93p inlet port, 96 fourth flow control valve, 100 machine tool, 110 workpiece support device, 111 support member, 111a workbench, 111b chuck, 112 Second rotary drive device, 113 tilt movement device, 120 movement device, 130 base, 140 control device, 140a main control device,141 Hardware processor, 142 Memory, 142a Data, 142b Program, 144 Communication circuit, 146 Input device, 146a Display with touch panel, 148 Bus, 171 Outer wall, 173 Opening, 175 Door, 291 Rod-shaped member, 293 Force-applying member, 440a First wall, 440b Second wall, 441 Annular protrusion, 751, 751a, 751b, 751c Inlet port, 752, 752a, 752b, 752c Outlet port, 753, 753a, 753b, 753c Vacuum port, 791 Exhaust purifier, 792 Recovery container, AC air curtain, AS, AS1, AS2, AT Air source, C Drive command, C1, C2, C3 Control command, CN Corner, CP1 First component, CP2 Second component, CT cut, E, E1 oil, G gap, G1 first gap, G2 second gap, G3 third gap, HD tool holder, J1 first movement command, OP1 air injection port, R1 first rotation command, R2 second rotation command, SP annular accommodation space, T tool, V1 first annular groove, V2 second annular groove, W workpiece.

Claims

1. A spindle lubrication device for a machine tool, comprising: a rotating body, holding the cutting tool; a plurality of bearings, including a first bearing and a second bearing; a housing that supports the rotating body so as to be rotatable about a first axis via the plurality of bearings; a mixed fluid supply device for supplying a mixed fluid containing oil and air to the plurality of bearings; as well as a recovery device for recovering the oily fluid containing the oil, The recovery device comprises: a plurality of recovery flow channels, provided in the housing, for recovering the oil-containing fluid from the plurality of bearings; a plurality of injectors disposed outside the housing; and Multiple flow control valves, The plurality of recycling channels include: a first recovery flow channel, mainly recovering a first oil-containing fluid discharged from at least one bearing including the first bearing; and The second recovery flow channel mainly recovers the second oil-containing fluid discharged from at least one bearing including the second bearing. The plurality of injectors comprises: a first ejector that generates negative pressure using first air supplied from a first air flow channel, thereby sucking the first oil-containing fluid from the first recovery flow channel; and The second ejector generates negative pressure by using the second air supplied from the second air flow channel, thereby sucking the second oil-containing fluid from the second recovery flow channel. The plurality of flow control valves include: a first flow control valve for adjusting a flow rate of the first air supplied from the first air flow passage to the first ejector; and The second flow control valve adjusts the flow rate of the second air supplied from the second air flow passage to the second ejector.

2. The spindle lubrication device for a machine tool according to claim 1, wherein: The spindle lubricating device of the machine tool further includes a plurality of pipes, the plurality of pipes including a first pipe connecting the first recovery flow channel and the first ejector fluid, and a second pipe connecting the second recovery flow channel and the second ejector fluid. Under a first condition in which the plurality of pipes are fluidically connected to the plurality of recovery flow passages, respectively, and a first flow rate of the mixed fluid is supplied from the mixed fluid supply device to the plurality of bearings, the flow rate of the first oil-containing fluid flowing in the first pipe is defined as a first recovery flow rate. Under a second condition that differs from the first condition in that only the plurality of pipes are fluidically separated from the plurality of recovery flow passages, the flow rate of the first oil-containing fluid discharged from the first recovery flow passage to the outside of the first recovery flow passage is defined as a first discharge flow rate, and the opening degree of the first flow control valve is set so that the first recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the first discharge flow rate. When the flow rate of the second oil-containing fluid flowing in the second pipe under the first condition is defined as a second recovery flow rate, and the flow rate of the second oil-containing fluid discharged from the second recovery flow channel to the outside of the second recovery flow channel under the second condition is defined as a second discharge flow rate, the opening of the second flow control valve is set so that the second recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the second discharge flow rate.

3. The spindle lubrication device for a machine tool according to claim 2, wherein: The plurality of recovery flow channels include a third recovery flow channel, the third recovery flow channel recovering a third oil-containing fluid containing the oil that has not been recovered by the first recovery flow channel but has passed through the first bearing. The plurality of pipes include a third pipe fluidically connecting the third recovery flow channel to a third ejector. The plurality of ejectors include the third ejector, which generates negative pressure in the third pipe by using the third air supplied from the third air flow channel, and draws the third oil-containing fluid from the third recovery flow channel through the third pipe. The plurality of flow control valves include a third flow control valve that adjusts a flow rate of the third air supplied from the third air flow passage to the third ejector.

4. The spindle lubrication device for a machine tool according to claim 1, wherein: The plurality of recovery flow channels include a third recovery flow channel, the third recovery flow channel recovering a third oil-containing fluid containing the oil that has not been recovered by the first recovery flow channel but has passed through the first bearing. The plurality of ejectors include a third ejector that generates negative pressure using third air supplied from a third air flow channel, thereby sucking the third oil-containing fluid from the third recovery flow channel. The plurality of flow control valves include a third flow control valve that adjusts a flow rate of the third air supplied from the third air flow passage to the third ejector.

5. The spindle lubrication device for a machine tool according to claim 4, wherein: The rotating body has: rear end; a front end portion for holding the cutting tool; A first portion, supporting an inner ring of the first bearing, having a first outer peripheral surface; a second portion having a second outer peripheral surface having a smaller diameter than the first outer peripheral surface and being arranged closer to the first direction side than the first portion when a direction from the rear end portion toward the front end portion is defined as a first direction; and a stepped surface connecting the first peripheral surface and the second peripheral surface, The housing has: a third part, supporting the outer ring of the first bearing; and a fourth portion defining an annular accommodation space for receiving the oil from a first gap between the first portion and the third portion, The fourth portion has an opening for guiding the oil from the annular accommodation space to the third recovery flow path. A second gap is formed between the housing and the step surface and is in fluid communication with the first gap. A third gap is formed between the housing and the second outer peripheral surface and is in fluid communication with the second gap.

6. The spindle lubrication device for a machine tool according to claim 5, wherein: The fourth portion has an annular protrusion protruding in a direction away from the first axis, The annular protrusion faces both the step surface and the annular accommodation space.

7. The spindle lubrication device for a machine tool according to any one of claims 4 to 6, wherein: The spindle lubrication device of the machine tool also has an air supply device, The air supply device comprises: an air source, disposed outside the housing; an air supply channel, disposed in the housing; an air supply pipe connecting the air source with the air supply flow channel and supplying fourth air to the air supply flow channel; and a fourth flow control valve for adjusting the flow rate of the fourth air supplied from the air supply pipe to the air supply flow channel; An air injection port is formed between the rotating body and the front end portion of the housing. A nozzle is formed in the shell, and the nozzle ejects the fourth air received from the air supply flow path into the gap in a manner that forms a first flow from the gap between the rotating body and the shell toward the third recovery flow path and a second flow from the gap toward the air injection port.

8. The spindle lubrication device for a machine tool according to claim 7, wherein: The spindle lubrication device of the machine tool further includes a plurality of pipes, the plurality of pipes including: a first pipe connecting the first recovery flow channel and the first injector fluid; a second pipe connecting the second recovery flow channel and the second injector fluid; and a third pipe connecting the third recovery flow channel and the third injector fluid. Under a third condition in which the plurality of pipes are fluidically connected to the plurality of recovery flow passages, a first flow rate of the mixed fluid is supplied from the mixed fluid supply device to the plurality of bearings, and a second flow rate of the fourth air is supplied to the air supply flow passage, the flow rate of the first oil-containing fluid flowing in the first pipe is defined as a first recovery flow rate. Under a fourth condition that is different from the third condition in that only the plurality of pipes are fluidically separated from the plurality of recovery flow passages, the flow rate of the first oil-containing fluid discharged from the first recovery flow passage to the outside of the first recovery flow passage is defined as a first discharge flow rate, and the opening degree of the first flow control valve is set so that the first recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the first discharge flow rate. When the flow rate of the second oil-containing fluid flowing in the second pipe is defined as a second recovery flow rate under the third condition, and the flow rate of the second oil-containing fluid discharged from the second recovery flow channel to the outside of the second recovery flow channel is defined as a second discharge flow rate under the fourth condition, the opening degree of the second flow control valve is set so that the second recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the second discharge flow rate.

9. The spindle lubrication device for a machine tool according to claim 8, wherein: The opening degrees of the third flow control valve and the fourth flow control valve are set so that the flow rate of the fourth air ejected from the ejection port is greater than the flow rate of the air ejected from the air ejection port.

10. A machine tool comprising: A machining head comprises: a rotating body for holding a tool; a plurality of bearings including a first bearing and a second bearing; a housing for rotatably supporting the rotating body via the plurality of bearings; and a first rotation drive device for rotating the rotating body about a first axis; a mixed fluid supply device for supplying a mixed fluid containing oil and air to the plurality of bearings; a recovery device for recovering the oily fluid containing the oil; a workpiece supporting device, supporting the workpiece; a moving device for moving the machining head relative to the workpiece supporting device; as well as a control device for controlling at least the first rotation drive device, the mixed fluid supply device, and the moving device; The recovery device comprises: a plurality of recovery flow channels, provided in the housing, for recovering the oil-containing fluid from the plurality of bearings; a plurality of injectors disposed outside the housing; and Multiple flow control valves, The plurality of recycling channels include: a first recovery flow channel, mainly recovering a first oil-containing fluid discharged from at least one bearing including the first bearing; and The second recovery flow channel mainly recovers the second oil-containing fluid discharged from at least one bearing including the second bearing. The plurality of injectors comprises: a first ejector that generates negative pressure using first air supplied from a first air flow channel, thereby sucking the first oil-containing fluid from the first recovery flow channel; and The second ejector generates negative pressure by using the second air supplied from the second air flow channel, thereby sucking the second oil-containing fluid from the second recovery flow channel. The plurality of flow control valves include: a first flow control valve for adjusting a flow rate of the first air supplied from the first air flow passage to the first ejector; and The second flow control valve adjusts the flow rate of the second air supplied from the second air flow passage to the second ejector.

11. The machine tool according to claim 10, further comprising: an outer wall surrounding the workpiece support device and the machining head when viewed from above; an opening formed in the outer wall for allowing the workpiece carried into the workpiece support device to pass therethrough; as well as a door for opening and closing the opening, The recovery device comprises: an exhaust conduit receiving exhaust gas from the plurality of injectors; as well as a recovery container, fluidly connected to the exhaust pipe, The recovery container is arranged at a position accessible to an operator's hand from outside the machine tool through the opening, or is arranged outside the outer wall.

12. The machine tool according to claim 10 or 11, wherein: The machine tool further includes a plurality of pipes including a first pipe fluidically connecting the first recovery flow channel and the first ejector, and a second pipe fluidically connecting the second recovery flow channel and the second ejector.

13. The machine tool according to claim 12, wherein: Under a first condition in which the plurality of pipes are fluidically connected to the plurality of recovery flow passages, respectively, and a first flow rate of the mixed fluid is supplied from the mixed fluid supply device to the plurality of bearings, the flow rate of the first oil-containing fluid flowing in the first pipe is defined as a first recovery flow rate. Under a second condition that differs from the first condition in that only the plurality of pipes are fluidically separated from the plurality of recovery flow passages, the flow rate of the first oil-containing fluid discharged from the first recovery flow passage to the outside of the first recovery flow passage is defined as a first discharge flow rate, and the opening degree of the first flow control valve is set so that the first recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the first discharge flow rate. When the flow rate of the second oil-containing fluid flowing in the second pipe under the first condition is defined as a second recovery flow rate, and the flow rate of the second oil-containing fluid discharged from the second recovery flow channel to the outside of the second recovery flow channel under the second condition is defined as a second discharge flow rate, the opening of the second flow control valve is set so that the second recovery flow rate is within a range of not less than 1 times and not more than 1.5 times the second discharge flow rate.

14. A method for using a machine tool, the method for using the machine tool according to claim 12, comprising: a step of deriving the first discharge flow rate by measurement or simulation under a second condition in which the plurality of pipes are fluidically separated from the plurality of recovery flow channels and a first flow rate of the mixed fluid is supplied from the mixed fluid supply device to the plurality of bearings, defining a flow rate of the first oil-containing fluid discharged from the first recovery flow channel to the outside of the first recovery flow channel as a first discharge flow rate; a step of deriving the second discharge flow rate by measurement or simulation when the flow rate of the second oil-containing fluid discharged from the second recovery flow channel to the outside of the second recovery flow channel under the second condition is defined as a second discharge flow rate; A step of deriving the first recovery flow rate by measurement or simulation under a first condition in which the plurality of pipes are fluidically connected to the plurality of recovery flow channels, respectively, and the mixed fluid at the first flow rate is supplied from the mixed fluid supply device to the plurality of bearings, defining the flow rate of the first oil-containing fluid flowing in the first pipe as a first recovery flow rate; A step of deriving the second recovery flow rate by measurement or simulation when the flow rate of the second oil-containing fluid flowing in the second pipe under the first condition is defined as a second recovery flow rate; a step of deriving a first opening degree of the first flow control valve so that a ratio of the first recovery flow rate to the first discharge flow rate falls within a predetermined range; a step of deriving a second opening degree of the second flow control valve so that a ratio of the second recovery flow rate to the second discharge flow rate falls within a predetermined range; supplying the mixed fluid to the plurality of bearings using the mixed fluid supply device; a step of operating the recovery device in a state where the opening of the first flow control valve is set to the first opening and the opening of the second flow control valve is set to the second opening; and The step of machining the workpiece using the tool held by the rotating body and rotating about the first axis.

15. The method for using a machine tool according to claim 14, wherein: The step of operating the recovery device includes recovering, via a third recovery flow path, a third oil-containing fluid containing the oil that has not been recovered by the first recovery flow path but has passed through the first bearing, The process of processing the workpiece is performed under the following conditions: A state in which the fourth air is supplied to the air supply flow path provided in the housing, A portion of the fourth air is ejected as an air curtain from an air ejection port formed between the rotating body and the front end portion of the housing, and A state in which a flow rate of the fourth air supplied to the air supply flow path is greater than a flow rate of the air ejected from the air ejection port.

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