Rotating Table Device

Abstract

To inhibit shifting of a rotation angle from a predetermined rotation angle when a table is stopped.SOLUTION: A rotary table device 30 includes: a base part 40 having a slide contacted surface 140; a table part 50 which has a slide contact surface 150 which makes slide contact with the slide contacted surface and is rotatably supported by the base part; a rotation driving part 200 which rotates the table part; a rotation brake part 300 which presses the slide contact surface to the slide contacted surface to brake rotation of the table part; and a fluid supply part which supplies a lubrication oil to a space between the slide contact surface and the slide contacted surface when the table part is rotated by the rotation driving part and supplies compressed air to the space between the slide contact surface and the slide contacted surface to discharge the lubrication oil from the space between the slide contact surface and the slide contacted surface when rotation of the table part is braked by the rotation brake part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a rotary table device. [Background technology]

[0002] Patent Document 1 discloses a rotary table device for a machine tool. In this rotary table device, a disk is fixed to the rotation axis of a table that rotates relative to a frame, and when braking the table, the disk is pinched between the friction surface of the frame and a piston, thereby braking the rotation of the table. When the table rotates, a lubricating oil is supplied to the gap between the friction surface of the frame and the disk, thereby suppressing wear of the friction surface and the disk. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-030302 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a rotary table device that brakes the rotation of the table by friction, as in Patent Document 1, the timing at which the desired braking torque is obtained may be delayed due to lubricating oil remaining on the friction surface, and the rotation angle when the table stops may deviate from the desired rotation angle. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a rotary table device comprising: a base portion having a sliding contact surface, a table portion having a sliding contact surface that comes into sliding contact with the sliding contact surface and rotatably supported by the base portion, a rotation drive portion that rotates the table portion, a rotation braking portion that brakes the rotation of the table portion by pressing the sliding contact surface against the sliding contact surface, and a fluid supply portion that supplies lubricating oil between the sliding contact surface and the sliding contact surface when the table portion is rotated by the rotation drive portion, and supplies compressed air between the sliding contact surface and the sliding contact surface to discharge the lubricating oil from between the sliding contact surface and the sliding contact surface when the rotation braking portion brakes the rotation of the table portion. According to this embodiment of the rotary table device, when the rotation of the table part is braked by the rotation brake part, the fluid supply part supplies compressed air between the sliding contact surface and the slidable contact surface to discharge the lubricating oil from between the sliding contact surface and the slidable contact surface, thereby preventing the rotation angle of the rotary table from deviating from the desired rotation angle when the rotary table is stopped. (2) In the rotary table device of the above aspect, when the table portion is rotated by the rotary drive unit, the fluid supply unit may supply oil air, which is a mixture of the lubricating oil and the compressed air, between the sliding contact surface and the slidable contact surface, thereby supplying the lubricating oil between the sliding contact surface and the slidable contact surface. According to the rotary table device of this embodiment, it is possible to increase the ease with which the lubricating oil can be discharged from between the sliding contact surface and the slidably contacted surface. (3) In the rotary table device of the above aspect, the lubricating oil may have a kinetic viscosity of 35.2 square millimeters per second or less at 40 degrees Celsius. According to the rotary table device of this embodiment, it is possible to increase the ease with which the lubricating oil can be discharged from between the sliding contact surface and the slidably contacted surface. The present disclosure may be realized in various forms other than a rotary table device, for example, a machine tool, a machining center, a gear skiving machine, or the like. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a schematic configuration of a machine tool according to a first embodiment. [Diagram 2] FIG. 1 is a cross-sectional view showing a schematic configuration of a rotary table device according to a first embodiment. [Diagram 3] FIG. 1 is an explanatory diagram illustrating a schematic configuration of a rotary table device according to a first embodiment. [Figure 4] FIG. 3 is a first partial enlarged view of part P in FIG. 2 . [Diagram 5] FIG. 3 is a second partially enlarged view of part P in FIG. 2 . [Figure 6] FIG. 2 is a top view showing the configuration of a sliding contact surface of the rotary table device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. First embodiment: FIG. 1 is a perspective view showing a schematic configuration of a machine tool 11 equipped with a rotary table device 30 in the first embodiment. In this embodiment, the machine tool 11 is configured as a horizontal machining center. The machine tool 11 has three coordinate axes, X, Y, and Z axes, which are perpendicular to each other. The X axis is a coordinate axis along the left-right direction of the machine tool 11, the Y axis is a coordinate axis along the up-down direction of the machine tool 11, and the Z axis is a coordinate axis along the front-rear direction of the machine tool 11. FIG. 1 shows arrows representing the coordinate axes of the machine tool 11, a character "+" representing the positive direction of the coordinate axes of the machine tool 11, and a character "-" representing the negative direction of the coordinate axes of the machine tool 11.

[0009] The machine tool 11 includes a bed 20, a rotary table device 30, a workpiece spindle device 70, a column 80, a saddle 90, a tool spindle device 91, and a control device 100. The bed 20 has a pair of first rails 21 provided along the Z axis, and a pair of second rails 26 provided along the X axis. The second rails 26 are provided in the -Z direction with respect to the first rails 21. The first rails 21 and the second rails 26 are provided on the upper surface of the bed 20. The upper surface means the surface facing the +Y direction. In the following description, the +Y direction may be referred to as "upper" and the -Y direction may be referred to as "lower."

[0010] The rotary table device 30 is disposed on the second rail 26. The rotary table device 30 moves along the X-axis while being guided by the second rail 26. In this embodiment, the rotary table device 30 moves along the X-axis by a servo motor (not shown). The servo motor that moves the rotary table device 30 is driven under the control of the control device 100. In this embodiment, each servo motor, such as a servo motor 82 described later, is also driven under the control of the control device 100 unless otherwise specified.

[0011] The rotary table device 30 includes a base portion 40 and a table portion 50. The base portion 40 has a portion that is connected to the second rail 26 of the rotary table device 30. The table portion 50 is disposed on the base portion 40, and is supported by the base portion 40 so as to be rotatable about a rotation axis parallel to the Y axis. In the following description, the rotation axis of the table portion 50 may be referred to as the B axis. A more specific configuration of the rotary table device 30 will be described later.

[0012] The work spindle device 70 is disposed on the table portion 50 and is fixed to the table portion 50. The work spindle device 70 has a work spindle, and the work spindle has a chuck device that grips the workpiece WK. In this embodiment, the work spindle device 70 rotates the workpiece WK gripped by the chuck device together with the work spindle by a servo motor (not shown). In the following description, the rotation axis of the workpiece WK may be referred to as the A-axis.

[0013] The column 80 is disposed on the first rail 21. The column 80 is connected to the first rail 21, and moves along the Z axis while being guided by the first rail 21. In this embodiment, the column 80 moves along the Z axis by a servo motor (not shown). The column 80 has a pair of third rails 81 provided along the Y axis. The third rails 81 are provided on the surface of the column 80 facing the -Z direction.

[0014] The saddle 90 is disposed in the -Z direction with respect to the third rail 81. The saddle 90 is connected to the third rail 81, and moves along the Y axis while being guided by the third rail 81. In this embodiment, the saddle 90 is moved along the Y axis by the servo motor 82.

[0015] The tool spindle device 91 is disposed in the -Z direction relative to the saddle 90 and is fixed to the saddle 90. A tool TL for machining a workpiece WK is attached to a tool spindle 92 of the tool spindle device 91. In this embodiment, the tool spindle 92 rotates the tool TL about a rotation axis parallel to the Z axis by a servo motor (not shown). In the following description, the rotation axis of the tool TL may be referred to as the C axis.

[0016] The control device 100 has a drive circuit that controls each servo motor, a programmable logic controller that controls a hydraulic oil pump 352, a first oil passage switching unit 353, a second oil passage switching unit 354, an air compressor 451, and a lubricating oil pump 453, which will be described later, and an NC control device that issues commands to the drive circuit and the programmable logic controller. In this embodiment, the control device 100 machines a workpiece WK using a tool TL by controlling each part of the machine tool 11, such as a servo motor that drives the tool spindle device 91 and a servo motor that drives the workpiece spindle device 70.

[0017] In the machine tool 11 of this embodiment, a skiving cutter is used as the tool TL, and the tool TL and the workpiece WK are moved relative to each other while the rotation of the tool TL and the rotation of the workpiece WK are linked, thereby performing skiving to form tooth grooves on the workpiece WK. As described later, in the machine tool 11 of this embodiment, deviation in the rotation angle of the table portion 50 of the rotary table device 30 is suppressed, and tooth grooves can be formed in the workpiece WK with good dimensional accuracy.

[0018] Fig. 2 is a cross-sectional view showing a schematic configuration of the turntable device 30 in this embodiment. Fig. 3 is an explanatory diagram showing a schematic configuration of the turntable device 30 in this embodiment. Fig. 4 is a first partial enlarged view of the part P in Fig. 2. Fig. 5 is a second partial enlarged view of the part P in Fig. 2. Fig. 6 is a top view showing the configuration of the sliding contact surface 140 of the turntable device 30 in this embodiment.

[0019] 2, in this embodiment, the rotary table device 30 includes, in addition to the above-mentioned base unit 40 and table unit 50, a thrust bearing 60, an encoder 110, and a rotary drive unit 200. As shown in FIG. 3, in this embodiment, the rotary table device 30 further includes a rotary braking unit 300 and a fluid supply unit 400.

[0020] As shown in Fig. 2, the base portion 40 includes a housing 41, a center shaft 45, and an encoder mount 46. The housing 41 includes a bottom portion 42, a side portion 43, and a partition portion 44. The bottom portion 42 includes the bottom surface of the rotary table device 30. The side portion 43 includes the side surface of the rotary table device 30, and is provided from the bottom portion 42 upward. The inner wall surface of the side portion 43 is configured in a cylindrical shape centered on the B axis.

[0021] The partition wall portion 44 is disposed between the B axis and the side surface portion 43. The partition wall portion 44 is configured in a cylindrical shape centered on the B axis, and is provided from the bottom surface portion 42 upward. The height of the partition wall portion 44 is lower than the height of the side surface portion 43. The partition wall portion 44 has a first convex portion 47 and a second convex portion 48. The first convex portion 47 is provided so as to protrude outward from the upper end portion of the partition wall portion 44. The second convex portion 48 is provided so as to protrude outward from between the first convex portion 47 and the bottom surface portion 42. The first convex portion 47 and the second convex portion 48 are configured in an annular shape centered on the B axis. A cylinder chamber that accommodates a part of a piston member 57 described later is provided between the first convex portion 47 and the second convex portion 48. The lower surface of the first convex portion 47 forms the upper wall surface of the cylinder chamber, and the upper surface of the second convex portion 48 forms the lower wall surface of the cylinder chamber. The surface of the partition wall 44 that connects the first protrusion 47 and the second protrusion 48 forms a side wall surface of the cylinder chamber.

[0022] The center shaft 45 is disposed between the B axis and the partition wall portion 44. The center shaft 45 is configured in a cylindrical shape centered on the B axis. The lower end portion of the center shaft 45 is configured in a flange shape and is fixed to the bottom surface portion 42. In this embodiment, the respective members of the rotary table device 30 are fixed to each other by screws, press fitting, or welding, unless otherwise specified.

[0023] The encoder mount 46 is disposed on the center shaft 45 and is fixed to the upper end of the center shaft 45. The encoder mount 46 is configured in a circular ring shape with the B axis as its center.

[0024] The encoder 110 is disposed on the encoder mount 46. In this embodiment, the encoder 110 is a rotary encoder and detects the rotation angle of the table portion 50. The encoder 110 includes a fixed portion 111 and a rotating portion 112. The fixed portion 111 is fixed to the encoder mount 46. The rotating portion 112 is fixed to the table portion 50 and rotates together with the table portion 50. An output signal from the encoder 110 is transmitted to the control device 100 via wiring (not shown) passing through the inside of the center shaft 45. The output signal from the encoder 110 is used by the control device 100 to control the rotation drive portion 200.

[0025] The table portion 50 includes a table main body 51, a table support portion 52, a center sleeve 53, a bearing holder 54, a collar 55, a first connecting member 56, a piston member 57, and a second connecting member 58.

[0026] The table main body 51 has an upper surface of the rotary table device 30. The above-mentioned workpiece spindle device 70 is fixed to the table main body 51. In this embodiment, the table main body 51 is configured in a disk shape centered on the B-axis. The table main body 51 is fixed to a table support portion 52.

[0027] The table support part 52 is configured in a cylindrical shape centered on the B-axis. The lower end part of the table support part 52 is accommodated inside the side part 43 of the housing 41. The table support part 52 has a through hole provided along the B-axis, and the upper end part of the center shaft 45, the encoder mount 46, and the encoder 110 described above are accommodated in the through hole of the table support part 52.

[0028] The center sleeve 53 is inserted into a through hole in the table support portion 52. The center sleeve 53 is configured in a cylindrical shape centered on the B axis. The upper end portion of the center sleeve 53 is configured in a flange shape and is fixed to the table support portion 52. The center shaft 45 is housed inside the center sleeve 53. The encoder mount 46 and the encoder 110 are disposed on the upper end portion of the center sleeve 53.

[0029] The bearing holder 54 is disposed below the table support portion 52, and between the center sleeve 53 and the partition portion 44 of the housing 41. The bearing holder 54 is configured in a cylindrical shape centered on the B axis. The upper end portion of the bearing holder 54 is configured in a flange shape, and is fixed to the table support portion 52. A thrust bearing 60 is disposed on the outer periphery of the bearing holder 54.

[0030] The thrust bearing 60 is configured in an annular shape centered on the B-axis. In this embodiment, the thrust bearing 60 is a ball bearing. The thrust bearing 60 may be, for example, a roller bearing instead of a ball bearing. The upper surface of an upper race 61 of the thrust bearing 60 contacts the downward surface of the partition wall portion 44, and the lower surface of a lower race 62 of the thrust bearing 60 contacts the upper surface of a collar 55. The collar 55 is fixed to the bearing holder 54 by a screw.

[0031] The first connecting member 56, the piston member 57, and the second connecting member 58 are disposed below the table support portion 52 and between the side portion 43 and the partition wall portion 44 of the housing 41. The first connecting member 56, the piston member 57, and the second connecting member 58 are disposed in this order downward from the table support portion 52. The first connecting member 56, the piston member 57, and the second connecting member 58 are configured in a cylindrical shape centered on the B axis. The first connecting member 56, the piston member 57, and the second connecting member 58 are fixed to each other.

[0032] As shown in Fig. 4, the base portion 40 has a sliding contact surface 140, and the table portion 50 has a sliding contact surface 150. The sliding contact surface 150 and the sliding contact surface 140 are arranged facing each other vertically. The sliding contact surface 150 is in sliding contact with the sliding contact surface 140. The sliding contact does not only mean that one object rotates so as to slide on the other object in a state where the one object is in direct contact with the other object, but also means that one object rotates so as to slide on the other object in a state where the one object is in contact with the other object via a fluid such as lubricating oil.

[0033] In this embodiment, the sliding contact surface 150 is provided on the bottom surface of the table support portion 52 in an annular shape centered on the B axis. More specifically, the sliding contact surface 150 is provided on a portion of the bottom surface of the table support portion 52 between a portion to which the first connecting member 56 is fixed and the outer periphery of the bottom surface of the table support portion 52. The housing 41 of the base portion 40 has a step portion on the upper end portion of the side surface portion 43, and the sliding contact surface 140 is provided on the step portion of the side surface portion 43 in an annular shape centered on the B axis.

[0034] As shown in FIG. 6, in this embodiment, the sliding contact surface 140 is provided with four first openings 141, four second openings 142, and four grooves 145. Each first opening 141 is provided in an inner portion of the sliding contact surface 140. The four first openings 141 are arranged at equal intervals along the circumferential direction centered on the B axis. Each second opening 142 is provided in an outer portion of the sliding contact surface 140. The four second openings 142 are arranged at equal intervals along the circumferential direction centered on the B axis. Each groove 145 is provided so as to connect each first opening 141 and each second opening 142. The number of first openings 141 provided in the sliding contact surface 140 is not limited to four, and may be any number of one or more. The number of second openings 142 provided in the sliding contact surface 140 is not limited to four, and may be any number of one or more. The number of grooves 145 provided on the sliding contact surface 140 is not limited to four, and may be any number equal to or greater than one. Also, the sliding contact surface 140 may not have any grooves 145 at all.

[0035] As shown in Fig. 4, each first opening 141 communicates with a fluid inlet 411 provided on the outer wall surface of the housing 41 shown in Fig. 2 via a first fluid passage 410 provided in the housing 41. Each second opening 142 communicates with a fluid outlet 421 provided on the outer wall surface of the housing 41 shown in Fig. 2 via a second fluid passage 420 provided in the housing 41.

[0036] The inner part of the piston member 57 is disposed in the cylinder chamber between the first convex portion 47 and the second convex portion 48. The thickness of the inner part of the piston member 57 is smaller than the distance between the first convex portion 47 and the second convex portion 48. The first hydraulic chamber HR1 is provided in the gap between the piston member 57 and the first convex portion 47, and the second hydraulic chamber HR2 is provided in the gap between the piston member 57 and the second convex portion 48. The first hydraulic chamber HR1 has an upper wall surface formed by the first convex portion 47, a side wall surface formed by the first connecting member 56, and a lower wall surface formed by the piston member 57. The second hydraulic chamber HR2 has an upper wall surface formed by the piston member 57, a side wall surface formed by a portion of the piston member 57 protruding downward, and a lower wall surface formed by the second convex portion 48. The first hydraulic chamber HR1 and the second hydraulic chamber HR2 are chambers formed by partitioning the cylinder chamber by the piston member 57.

[0037] The first hydraulic chamber HR1 communicates with a first hydraulic oil supply / discharge port 311 provided on the outer wall surface of the housing 41 shown in Fig. 2 via a first hydraulic oil passage 310 provided in the housing 41. The second hydraulic chamber HR2 communicates with a second hydraulic oil supply / discharge port 321 provided on the outer wall surface of the housing 41 shown in Fig. 2 via a second hydraulic oil passage 320 provided in the housing 41.

[0038] As shown in FIG. 2, the rotary drive unit 200 rotates the table unit 50 around the B axis. In this embodiment, the rotary drive unit 200 includes a worm gear mechanism 210 and a servo motor 220. The worm gear mechanism 210 includes a worm wheel 211 configured as a helical gear and a worm shaft 212 configured as a screw gear. The worm wheel 211 is configured in an annular shape and is arranged to surround the partition wall portion 44 of the housing 41. The worm wheel 211 is fixed to the second connection member 58 of the table unit 50. The worm shaft 212 is configured in a cylindrical shape and is arranged so that the teeth of the worm wheel 211 and the teeth of the worm shaft 212 mesh with each other. The servo motor 220 is connected to an end of the worm shaft 212. The servo motor 220 rotates the worm shaft 212 to rotate the worm wheel 211 and the table unit 50. The servo motor 220 is driven under the control of the control device 100. In another embodiment, the rotation drive unit 200 may be configured by a direct drive motor, and the output shaft of the direct drive motor may be fixed to the second connection member 58.

[0039] As shown in FIG. 3, in this embodiment, the rotation braking unit 300 includes a hydraulic oil supply / discharge unit 350. The hydraulic oil supply / discharge unit 350 has a function of supplying hydraulic oil to the first hydraulic chamber HR1 and the second hydraulic chamber HR2 described above, and a function of discharging hydraulic oil from the first hydraulic chamber HR1 and the second hydraulic chamber HR2. As shown in FIG. 5, the rotation braking unit 300 presses the sliding contact surface 150 against the sliding contact surface 140 by supplying hydraulic oil from the hydraulic oil supply / discharge unit 350 to the first hydraulic chamber HR1. The rotation braking unit 300 brakes the rotation of the table unit 50 by friction between the sliding contact surface 150 and the sliding contact surface 140 generated by pressing the sliding contact surface 150 against the sliding contact surface 140.

[0040] As shown in FIG. 3, in this embodiment, the hydraulic oil supply / discharge unit 350 includes a hydraulic oil tank 351, a hydraulic oil pump 352, a first oil passage switching unit 353, and a second oil passage switching unit 354. The hydraulic oil tank 351 stores hydraulic oil. The hydraulic oil tank 351 is connected to an intake port of the hydraulic oil pump 352 via a pipe. The discharge port of the hydraulic oil pump 352 is connected to the first oil passage switching unit 353 and the second oil passage switching unit 354 by a branched pipe. The hydraulic oil pump 352 pumps hydraulic oil from the hydraulic oil tank 351 through the discharge port. In this embodiment, the hydraulic oil pump 352 is driven under the control of the programmable logic controller of the control device 100.

[0041] The first oil passage switching unit 353 and the second oil passage switching unit 354 are driven under the control of the programmable logic controller of the control device 100 to switch the path through which the hydraulic oil flows. The first oil passage switching unit 353 and the second oil passage switching unit 354 are configured by, for example, a three-way valve. The first oil passage switching unit 353 is connected to the first hydraulic oil supply / discharge port 311 and the hydraulic oil tank 351 by different piping. The second oil passage switching unit 354 is connected to the second hydraulic oil supply / discharge port 321 and the hydraulic oil tank 351 by different piping. The first oil passage switching unit 353 switches between a state in which the first hydraulic chamber HR1 and the hydraulic oil tank 351 communicate with each other via the hydraulic oil pump 352 and a state in which the first hydraulic chamber HR1 and the hydraulic oil tank 351 communicate with each other without the hydraulic oil pump 352. The second oil passage switching unit 354 switches between a state in which the second hydraulic chamber HR2 and the hydraulic oil tank 351 are connected via the hydraulic oil pump 352 and a state in which the second hydraulic chamber HR2 and the hydraulic oil tank 351 are connected without passing through the hydraulic oil pump 352.

[0042] FIG. 4 shows a state in which braking of the table section 50 by the rotation braking section 300 is released. In a state in which the second hydraulic chamber HR2 and the hydraulic oil tank 351 communicate with each other via the hydraulic oil pump 352 and the first hydraulic chamber HR1 and the hydraulic oil tank 351 communicate with each other without the hydraulic oil pump 352, the hydraulic oil pump 352 is driven to supply hydraulic oil to the second hydraulic chamber HR2. When hydraulic oil is supplied to the second hydraulic chamber HR2, the piston member 57 is pressed upward by the hydraulic oil in the second hydraulic chamber HR2, and the table section 50 rises. At this time, hydraulic oil is discharged from the first hydraulic chamber HR1 to the hydraulic oil tank 351. As the table section 50 rises and the gap between the sliding contact surface 150 and the slidable contact surface 140 increases, braking of the table section 50 by the rotation braking section 300 is released. In this embodiment, the gap between the sliding contact surface 150 and the slidable contact surface 140 is widened to about 50 micrometers. Note that, in this embodiment, the thrust bearing 60 is provided, so that the gap between the sliding contact surface 150 and the slidable contact surface 140 can be prevented from becoming too wide.

[0043] 5 shows a state in which the rotation of the table section 50 is braked by the rotation brake section 300. In a state in which the first hydraulic chamber HR1 and the hydraulic oil tank 351 communicate with each other via the hydraulic oil pump 352 and the second hydraulic chamber HR2 and the hydraulic oil tank 351 communicate with each other without the hydraulic oil pump 352, the hydraulic oil pump 352 is driven to supply hydraulic oil to the first hydraulic chamber HR1. When hydraulic oil is supplied to the first hydraulic chamber HR1, the piston member 57 is pressed downward by the hydraulic oil in the first hydraulic chamber HR1, and the table section 50 descends. At this time, hydraulic oil is discharged from the second hydraulic chamber HR2 to the hydraulic oil tank 351. The table section 50 descends and the sliding contact surface 150 is pressed against the sliding contact surface 140, thereby applying a braking torque to the table section 50.

[0044] 3, in this embodiment, the fluid supply unit 400 includes an air compressor 451, a lubricating oil tank 452, a lubricating oil pump 453, and a mixing valve 454. The fluid supply unit 400 has a function of supplying lubricating oil between the sliding contact surface 150 and the slidable contact surface 140, and a function of supplying compressed air between the sliding contact surface 150 and the slidable contact surface 140.

[0045] The air compressor 451 generates compressed air by drawing in the atmosphere from an intake port, and pressure-feeds the compressed air from an exhaust port. In this embodiment, a filter for collecting dust contained in the atmosphere is provided at the intake port of the air compressor 451. The air compressor 451 is driven under the control of the programmable logic controller of the control device 100.

[0046] The lubricant tank 452 stores a lubricant. In this embodiment, the lubricant tank 452 stores a lubricant with an ISO viscosity grade number of "ISO VG 32", that is, a lubricant with a kinetic viscosity of 28.8 mm2 / s or more and 35.2 mm2 / s or less at 40 degrees Celsius. The lubricant tank 452 is connected to an intake port of a lubricant pump 453 via a pipe. The lubricant pump 453 pumps the lubricant from the lubricant tank 452 through a discharge port. In this embodiment, the lubricant pump 453 is driven under the control of a programmable logic controller of the control device 100.

[0047] The mixing valve 454 has two inlets and one discharge port. One inlet of the mixing valve 454 is connected to the air compressor 451 via a pipe, and the other inlet of the mixing valve 454 is connected to the discharge port of the lubricating oil pump 453 via a pipe. The discharge port of the mixing valve 454 is connected to the fluid inlet 411 shown in FIG. 2 via a pipe.

[0048] When compressed air is supplied to the mixing valve 454 from the air compressor 451 and lubricating oil is supplied to the mixing valve 454 from the lubricating oil pump 453, the mixing valve 454 generates oil air in which the compressed air and lubricating oil are mixed by intermittently supplying a fixed amount of lubricating oil to the jet of compressed air, and discharges the oil air from the discharge port.

[0049] When compressed air is supplied to the mixing valve 454 from the air compressor 451 and lubricating oil is not supplied to the mixing valve 454 from the lubricating oil pump 453, the mixing valve 454 discharges compressed air from a discharge port. In the following description, the compressed air discharged from the mixing valve 454 when compressed air is supplied to the mixing valve 454 from the air compressor 451 and lubricating oil is not supplied to the mixing valve 454 from the lubricating oil pump 453 is referred to as dry air.

[0050] The oil-air and dry air discharged from the mixing valve 454 flow through the fluid inlet 411, the first fluid passage 410, and the first opening 141 shown in FIG. 2 in this order, and are supplied between the sliding contact surface 150 and the sliding contact surface 140. The oil-air and dry air that flow into the second opening 142 from between the sliding contact surface 150 and the sliding contact surface 140 flow through the second opening 142, the second fluid passage 420, and the fluid discharge port 421 in this order. As shown in FIG. 3, in this embodiment, the lubricant oil recovery container 460 is connected to the fluid discharge port 421 via a pipe. The oil-air and dry air discharged from the fluid discharge port 421 are collected in the lubricant oil recovery container 460. In this embodiment, the lubricant oil recovery container 460 is provided with an air vent hole, and the compressed air and dry air contained in the oil-air are discharged to the outside of the lubricant oil recovery container 460 through the air vent hole.

[0051] In this embodiment, the control device 100 can switch between a state in which oil air is discharged from the mixing valve 454 and a state in which dry air is discharged from the mixing valve 454 by controlling the air compressor 451 and the lubricating oil pump 453.

[0052] As shown in FIG. 4, when the control device 100 rotates the table portion 50 by the rotation drive unit 200, the control device 100 supplies lubricating oil between the sliding contact surface 150 and the slidable contact surface 140 by supplying oil air from the mixing valve 454 to between the sliding contact surface 150 and the slidable contact surface 140 through the first opening 141. The lubricating oil supplied from the first opening 141 between the sliding contact surface 150 and the slidable contact surface 140 flows along the groove portion 145. By the rotation of the table portion 50, the lubricating oil in the groove portion 145 is spread over the entire area of ​​the sliding contact surface 150 and the entire area of ​​the slidable contact surface 140. Therefore, the lubricating oil contained in the oil air can suppress wear of the sliding contact surface 150 and the slidable contact surface 140 due to the rotation of the table portion 50.

[0053] Further, in this embodiment, as shown in FIG. 3, the piping connecting the mixing valve 454 and the fluid inlet 411 is branched, and the piping branched from between the mixing valve 454 and the fluid inlet 411 is connected to the work spindle device 70. The oil-air discharged from the mixing valve 454 is supplied not only to the rotary table device 30 but also to the work spindle device 70. Therefore, the lubricating oil contained in the oil-air can suppress wear of the work spindle device 70 when the work spindle device 70 rotates the work WK around the A-axis. The oil-air discharged from the work spindle device 70 is collected in the lubricating oil recovery container 460 via the piping connecting the work spindle device 70 and the lubricating oil recovery container 460.

[0054] 5, when the control device 100 brakes the rotation of the table portion 50 by the rotation braking portion 300, the control device 100 supplies dry air from the mixing valve 454 to between the sliding contact surface 150 and the sliding-receiving contact surface 140 through the first opening 141, thereby pushing the lubricating oil between the sliding contact surface 150 and the sliding-receiving contact surface 140 toward the second opening 142, thereby discharging the lubricating oil from between the sliding contact surface 150 and the sliding-receiving contact surface 140. The timing at which the dry air is supplied between the sliding contact surface 150 and the sliding-receiving contact surface 140 is preferably before the sliding contact surface 150 comes into contact with the sliding-receiving contact surface 140.

[0055] In the machine tool 11 of the present embodiment described above, when the rotation of the table portion 50 is braked by the rotation braking portion 300, the fluid supply portion 400 supplies dry air between the sliding contact surface 150 and the slidable contact surface 140 from the mixing valve 454, thereby discharging lubricating oil from between the sliding contact surface 150 and the slidable contact surface 140. Therefore, it is possible to suppress the rotation angle of the table portion 50 at the time of stopping from deviating from the desired rotation angle due to a delay in the timing at which the desired braking torque is obtained. In particular, when skiving is performed on the workpiece WK, the machine tool 11 repeats a cycle in which the braking of the table portion 50 by the rotation braking portion 300 is released, the rotation angle of the table portion 50 is changed by the rotation drive portion 200, the table portion 50 is braked by the rotation braking portion 300, the rotary table device 30 is moved along the X-axis, and the workpiece WK is machined. When the rotary table device 30 is moved along the X-axis, a moment of force that rotates the table part 50 may occur. If lubricating oil remains between the sliding contact surface 150 and the slidable contact surface 140, the moment of force that occurs when the rotary table device 30 is moved along the X-axis may cause the rotation angle of the table part 50 to shift. In this embodiment, when the rotation of the table part 50 is braked by the rotation braking part 300, the fluid supply part 400 supplies dry air between the sliding contact surface 150 and the slidable contact surface 140 to discharge the lubricating oil from between the sliding contact surface 150 and the slidable contact surface 140, so that the moment of force that occurs when the rotary table device 30 is moved along the X-axis can also be suppressed from causing the rotation angle of the table part 50 to shift.

[0056] In addition, in this embodiment, when the table part 50 is rotated by the rotation braking part 300, the mixing valve 454 of the fluid supply part 400 generates oil air by intermittently supplying a fixed amount of lubricating oil to the jet of compressed air, and supplies the oil air between the sliding contact surface 150 and the sliding contact surface 140. In the form in which the lubricating oil is supplied by the oil air, it is easier to supply the desired amount of lubricating oil than in the form in which the lubricating oil is supplied by the oil mist generated by atomizing the lubricating oil using the Venturi effect. Therefore, it is possible to suppress the lubricating oil from being difficult to be discharged from between the sliding contact surface 150 and the sliding contact surface 140 due to the lubricating oil being supplied between the sliding contact surface 150 and the sliding contact surface 140 in an amount greater than the desired supply amount.

[0057] In this embodiment, the fluid supply unit 400 supplies lubricating oil having a kinetic viscosity of 35.2 square millimeters per second or less at 40 degrees Celsius between the sliding contact surface 150 and the sliding-receiving contact surface 140 by oil air. Therefore, compared to a configuration in which lubricating oil having a kinetic viscosity of more than 35.2 square millimeters per second at 40 degrees Celsius is supplied between the sliding contact surface 150 and the sliding-receiving contact surface 140, it is possible to increase the ease with which the lubricating oil is discharged from between the sliding contact surface 150 and the sliding-receiving contact surface 140.

[0058] B. Other embodiments: (B1) In the above-described embodiment, when the table portion 50 is rotated by the rotation braking portion 300, the fluid supply portion 400 supplies lubricating oil between the sliding contact surface 150 and the slidable contact surface 140 by supplying oil air between the sliding contact surface 150 and the slidable contact surface 140. In contrast to this, when the table portion 50 is rotated by the rotation braking portion 300, the fluid supply portion 400 may supply lubricating oil between the sliding contact surface 150 and the slidable contact surface 140 by, for example, supplying oil mist between the sliding contact surface 150 and the slidable contact surface 140.

[0059] (B2) In the above-described embodiment, when the table part 50 is rotated by the rotation braking part 300, the fluid supply part 400 supplies a lubricant having a kinetic viscosity of 35.2 square millimeters per second or less at 40 degrees Celsius between the sliding contact surface 150 and the sliding contact surface 140. In contrast, when the table part 50 is rotated by the rotation braking part 300, the fluid supply part 400 may supply a lubricant having a kinetic viscosity of more than 35.2 square millimeters per second at 40 degrees Celsius between the sliding contact surface 150 and the sliding contact surface 140. For example, a lubricant having an ISO viscosity grade number of "ISO VG 68", that is, a lubricant having a kinetic viscosity of 61.2 square millimeters per second or more and 74.8 square millimeters per second or less at 40 degrees Celsius, may be supplied between the sliding contact surface 150 and the sliding contact surface 140.

[0060] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention column can be appropriately replaced or combined to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0061] 11...machine tool, 20...bed, 30...rotary table device, 40...base portion, 41...housing, 45...center shaft, 47...first convex portion, 48...second convex portion, 50...table portion, 51...table body, 52...table support portion, 53...center sleeve, 57...piston member, 60...thrust bearing, 70...work spindle rotation device, 80...column, 90...saddle, 91...tool spindle rotation device, 92...tool spindle, 100...control device, 140...sliding contact surface, 150...sliding contact surface, 200...rotation drive portion, 210...worm gear mechanism, 220...servo motor, 300...rotation braking portion, 350...hydraulic oil supply / discharge portion, 400...fluid supply portion, HR1...first hydraulic chamber, HR2...second hydraulic chamber, TL...tool, WK...work

Claims

1. A rotary table device, A base portion having a sliding contact surface; a table portion having a sliding contact surface that is in sliding contact with the sliding contact surface and rotatably supported by the base portion; A rotation drive unit that rotates the table unit; a rotation braking portion that brakes the rotation of the table portion by pressing the sliding contact surface against the sliding contact surface; a fluid supply section which supplies lubricating oil between the sliding contact surface and the slidable contact surface when the table section is rotated by the rotation drive section, and which discharges the lubricating oil from between the sliding contact surface and the slidable contact surface by supplying compressed air between the sliding contact surface and the slidable contact surface when the rotation of the table section is braked by the rotation brake section; a control device that controls the fluid supply unit such that the compressed air is supplied between the sliding contact surface and the sliding contact surface before the sliding contact surface comes into contact with the sliding contact surface; A rotary table device comprising:

2. 2. The rotary table device according to claim 1, A rotary table device in which, when the table portion is rotated by the rotary drive portion, the fluid supply portion supplies oil air, which is a mixture of the lubricating oil and the compressed air, between the sliding contact surface and the slidable contact surface, thereby supplying the lubricating oil between the sliding contact surface and the slidable contact surface.

3. 3. The rotary table device according to claim 1, The lubricating oil has a kinetic viscosity of 35.2 square millimeters per second or less at 40 degrees Celsius.

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