Rotary table unit and machine tool

Abstract

A rotary table unit (100) includes a rotary table (21) rotatable about a predetermined axis (101), a tailstock (41) disposed opposite the rotary table (21) in an axial direction of the predetermined axis (101), and a holding member (31) that includes a first support portion (36) supporting the rotary table (21), a second support portion (32) supporting the tailstock (41), and a connection portion (38) connecting the first support portion (36) and the second support portion (32), holds the rotary table (21) and the tailstock (41), and is stationary in a circumferential direction of the predetermined axis (101) when the rotary table (21) is rotating.

Description

ROTARY TABLE UNIT AND MACHINE TOOL

[0001] The present invention relates to a rotary table unit and a machine tool.

[0002] For example, Japanese Patent Laying-Open No. 2017-013140 (PTL 1) discloses a vertical lathe that includes a cutter base portion movable freely and a rotary table rotatable about a rotation central axis extending in the vertical direction and performs turning on a workpiece placed on and fixed to the rotary table using a turning tool held by the cutter base portion.

[0003] Japanese Patent Laying-Open No. 2017-013140

[0004] As disclosed in PTL 1 mentioned above, it is known to perform turning for machining a workpiece using a fixed tool, with the workpiece being rotated, in a machine tool including a rotary table, such as a five-axis machine tool. When turning is performed on a long workpiece in such a machine tool, the amount of deflection of the workpiece relative to the rotational center of the rotary table becomes large, and the precision of the machining on the workpiece may decrease accordingly.

[0005] In view of the above, the present invention is aimed at providing a rotary table unit that enables it to increase the precision of machining on a workpiece, and a machine tool including such a rotary table unit.

[0006] A rotary table unit according to the present invention includes a rotary table rotatable about a predetermined axis, a tailstock disposed opposite the rotary table in an axial direction of the predetermined axis, and a holding member that includes a first support portion supporting the rotary table, a second support portion supporting the tailstock, and a connection portion connecting the first support portion and the second support portion, holds the rotary table and the tailstock, and is stationary in a circumferential direction of the predetermined axis when the rotary table is rotating.

[0007] A machine tool according to the present invention includes the rotary table unit, and a transfer unit that transfers the rotary table unit between the inside and outside of a machining area.

[0008] According to the present invention, a rotary table unit that enables it to increase the precision of workpiece machining and a machine tool including such a rotary table unit can be provided.

[0009] Fig. 1 is a perspective view illustrating a rotary table unit according to an embodiment of the present invention.Fig. 2 is a top view illustrating an internal structure of a machine tool including the rotary table unit in Fig. 1.Fig. 3 is a cross-sectional view illustrating the machine tool, which is taken along a line with arrows III-III in Fig. 2.Fig. 4 is a cross-sectional view illustrating the machine tool in Fig. 3 (at the time of transferring the rotary table unit).Fig. 5 is a diagram schematically illustrating an internal structure of a tailstock (at the time of clamping a workpiece).Fig. 6 is a diagram schematically illustrating the internal structure of the tailstock (at the time of unclamping the workpiece).Fig. 7 is a cross-sectional view of the machine tool for explaining a rotation stop mechanism for a holding member.Fig. 8 is another cross-sectional view of the machine tool for explaining the rotation stop mechanism for the holding member.Fig. 9 is a cross-sectional view illustrating a variation of the rotation stop mechanism in Fig. 7.

[0010] Embodiments of the present invention are described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference characters.

[0011] Fig. 1 is a perspective view illustrating a rotary table unit according to an embodiment of the present invention. Fig. 2 is a top view illustrating an internal structure of a machine tool including the rotary table unit in Fig. 1.

[0012] Referring to Figs. 1 and 2, machine tool 10 is a machining center that performs workpiece machining by causing a rotating tool to come into contact with a workpiece in a still state. Machine tool 10 includes a rotary table 21. Machine tool 10 is further provided with a turning function of performing workpiece machining by causing a tool to come into contact with a workpiece while the workpiece is being rotated using rotary table 21.

[0013] Machine tool 10 is a numerical control (NC) machine tool where various kinds of operations for workpiece machining are automated through numerical control by a computer.

[0014] Herein, the axis that is parallel to the direction of the rotation axis of a workpiece and extends in the up-and-down direction is referred to as a "Z axis", the axis that is parallel to the direction in which a tool approaches the workpiece rotating and extends in the horizontal direction is referred to as an "X axis", and the axis that is in the direction orthogonal to the X axis and extends in the horizontal direction is referred to as a "Y axis". Although the X axis, the Y axis, and the Z axis are set as stated above for convenience in describing the structures of machine tool 10 and rotary table unit 100, these do not necessarily agree with the X axis, the Y axis, and the Z axis defined in a machining center.

[0015] First, the structure of machine tool 10 is described. Machine tool 10 includes a cover body 18, a tool spindle 12, rotary table unit 100, and a base member 51.

[0016] Cover body 18 defines a machining area 16 and forms the outer appearance of machine tool 10. Machining area 16 is a space where a workpiece is machined, and is sealed so that a foreign substance caused in the workpiece machining, such as chips or cutting oil, will not leak out of machining area 16.

[0017] Tool spindle 12 is provided in machining area 16. Driven by a motor, tool spindle 12 is rotatable about a rotation central axis 103 parallel to the X axis. A clamp mechanism for holding a tool so that the tool is detachable is provided on tool spindle 12. One of a rotary tool, such as a drill, a reamer, or a milling cutter, and a fixed tool T for turning is selectively held by tool spindle 12. In Fig. 2, tool spindle 12 holds fixed tool T.

[0018] Rotary table unit 100 is an apparatus for fixing a workpiece W. Rotary table unit 100 includes rotary table 21. Rotary table 21 is rotatable about a predetermined axis 101 parallel to the Z axis (the up-and-down direction).

[0019] Rotary table 21 includes a surface plate portion 26. Surface plate portion 26 is a palette made of metal. Surface plate portion 26 is constituted of a circular plate that has a thickness direction corresponding to the axial direction of predetermined axis 101 and is centered on predetermined axis 101. Workpiece W is placed on surface plate portion 26. Workpiece W is constituted of a long body that has a longitudinal direction corresponding to the axial direction of predetermined axis 101. Workpiece W has a shape of a cylinder centered on predetermined axis 101. The entire length of workpiece W may be larger than the diameter of workpiece W, may be larger than or equal to double the diameter of workpiece W, or may be larger than or equal to quadruple the diameter of workpiece W. With the rotation of rotary table 21, workpiece W rotates about predetermined axis 101.

[0020] Base member 51 is provided in machining area 16. Rotary table unit 100 is placed on base member 51. Base member 51 is fixed in machining area 16.

[0021] The axial configuration of machine tool 10 described above is an example and is not particularly limited. For example, the axial configuration may allow tool spindle 12 to move in the Y axis direction and the Z axis direction and allow base member 51 to move in the X axis direction. Base member 51 may be structured so as to be rotatable (tiltable) about a rotation central axis parallel to the Y axis so that the tilt of predetermined axis 101 corresponding to the rotation central axis of rotary table 21 varies within an X-Z axes plane.

[0022] Machine tool 10 further includes a transfer unit 61 and a turn cover 66. Transfer unit 61 transfers rotary table unit 100 between the inside and outside of machining area 16. An external space outside machining area 16 corresponds to a set-up station 17.

[0023] Set-up station 17 is a space for attaching a workpiece to be machined in machining area 16 to rotary table unit 100 and removing the workpiece after the machining in machining area 16 from rotary table unit 100. A set-up-side placement base 56 for placing rotary table unit 100 is provided in set-up station 17.

[0024] In Fig. 2, a boundary surface 110 is illustrated, which is parallel to a Y-Z axes plane and forms the boundary between machining area 16 and set-up station 17. Turn cover 66 is provided, overlapping boundary surface 110. Machining area 16 and set-up station 17 are separated from each other by turn cover 66.

[0025] Transfer unit 61 includes a first arm member 62A, a second arm member 62B, and a joint portion 63.

[0026] First arm member 62A is constituted of a pair of arms, which are provided with a clearance left between each other in the Y axis direction and extend from joint portion 63 in one direction along the X axis direction. Second arm member 62B is constituted of a pair of arms, which are provided with a clearance left between each other in the Y axis direction and extend from joint portion 63 in the opposite direction along the X axis direction.

[0027] Joint portion 63 joins first arm member 62A and second arm member 62B together. An end portion of first arm member 62A in the X axis direction is connected to joint portion 63. An end portion of second arm member 62B in the X axis direction is connected to joint portion 63. Joint portion 63 is provided immediately under turn cover 66. Turn cover 66 is connected to joint portion 63.

[0028] First arm member 62A and second arm member 62B are provided so as to be slidable in the Z axis direction (the up-and-down direction) and turnable about a turn central axis 102 by 180° via an arm driving mechanism (not illustrated) connected to joint portion 63. Turn central axis 102 extends in the Z axis direction, overlapping boundary surface 110.

[0029] First arm member 62A and second arm member 62B move reversely between machining area 16 and set-up station 17 by turning about turn central axis 102 by 180°. Turn cover 66 turns about turn central axis 102 by 180° together with first arm member 62A and second arm member 62B.

[0030] In Fig. 2, first arm member 62A and second arm member 62B are disposed in machining area 16 and set-up station 17, respectively. First arm member 62A lifts a first rotary table unit 100A from base member 51 by sliding upward. Second arm member 62B lifts a second rotary table unit 100B from set-up-side placement base 56 by sliding upward.

[0031] First arm member 62A transfers first rotary table unit 100A from machining area 16 to set-up station 17 by turning about turn central axis 102 by 180°. Second arm member 62B transfers second rotary table unit 100B from set-up station 17 to machining area 16 by turning about turn central axis 102 by 180°. First arm member 62A places first rotary table unit 100A on set-up-side placement base 56 by sliding downward. Second arm member 62B places second rotary table unit 100B on base member 51 by sliding downward.

[0032] The structure of rotary table unit 100 is described in detail next. Fig. 3 is a cross-sectional view illustrating the machine tool, which is taken along a line with arrows III-III in Fig. 2. Fig. 4 is a cross-sectional view illustrating the machine tool in Fig. 3 (at the time of transferring the rotary table unit).

[0033] Referring to Figs. 1 to 4, rotary table 21 further includes a bearing housing 24, a shaft 22, and a bearing 29. Shaft 22 extends on predetermined axis 101. Surface plate portion 26 is connected to one end portion of shaft 22 in the axial direction of predetermined axis 101. Surface plate portion 26 extends outward from an end portion of shaft 22 in the radial direction of predetermined axis 101.

[0034] Bearing housing 24 is provided on the outer periphery of shaft 22. Bearing 29 is interposed between bearing housing 24 and shaft 22 in the radial direction of predetermined axis 101. Bearing 29 tolerates rotary motion of shaft 22 in relation to bearing housing 24 on the fixed side.

[0035] Shaft 22 includes a clutch shaft 25. Clutch shaft 25 extends on predetermined axis 101. Clutch shaft 25 projects from the other end portion of shaft 22 in the axial direction of predetermined axis 101.

[0036] Machine tool 10 further includes a motor 52. Motor 52 is provided inside base member 51. As illustrated in Fig. 3, when rotary table unit 100 is placed on base member 51, clutch shaft 25 is coupled to an output shaft 53 of motor 52. The rotary motion transferred from motor 52 to shaft 22 causes surface plate portion 26 to rotate about predetermined axis 101.

[0037] Rotary table unit 100 further includes a tailstock 41. Tailstock 41 is disposed opposite rotary table 21 (surface plate portion 26) in the axial direction of predetermined axis 101. Workpiece W is placed between tailstock 41 and surface plate portion 26 in the axial direction of predetermined axis 101.

[0038] Tailstock 41 includes an exterior body 42 and a center 46. Exterior body 42 has a shape of a cylinder centered on predetermined axis 101 as a whole and forms the outer appearance of tailstock 41. The diameter of exterior body 42 centered on predetermined axis 101 is smaller than the diameter of surface plate portion 26 centered on predetermined axis 101.

[0039] Center 46 extends on predetermined axis 101. Center 46 has a shape of a pin projecting toward rotary table 21. Center 46 is provided so that center 46 can approach or recede from workpiece W placed on rotary table 21 by sliding in the axial direction of predetermined axis 101. Tailstock 41 is a quill type, where center 46 is attached to a quill (not illustrated). Tailstock 41 is not limited to this but may be a rotary center type, where center 46 is supported by a bearing.

[0040] Fig. 5 is a diagram schematically illustrating an internal structure of the tailstock (at the time of clamping the workpiece). Fig. 6 is a diagram schematically illustrating the internal structure of the tailstock (at the time of unclamping the workpiece).

[0041] Referring to Figs. 5 and 6, tailstock 41 further includes a slide mechanism 70 and a lock mechanism 71.

[0042] Slide mechanism 70 slides center 46 in the axial direction of predetermined axis 101 by being supplied with hydraulic pressure. Slide mechanism 70 is constituted of a hydraulic cylinder and provided adjacent, in the axial direction of predetermined axis 101, to the quill (not illustrated) to which center 46 is attached. Slide mechanism 70 moves center 46 to a position in which center 46 abuts on workpiece W placed on rotary table 21 by being supplied with hydraulic oil for clamping. Slide mechanism 70 moves center 46 to a position located away from workpiece W placed on rotary table 21 by being supplied with hydraulic oil for unclamping.

[0043] Lock mechanism 71 is structured so that center 46 is fixed in the position in which center 46 abuts on workpiece W placed on rotary table 21 even when no hydraulic pressure is being supplied to slide mechanism 70.

[0044] More specifically, lock mechanism 71 includes a piston cylinder 74, a housing 72, a wedge member 73, and a spring member 75. In piston cylinder 74, a piston (not illustrated) is provided, which can execute strokes in the axial direction of predetermined axis 101 using the hydraulic pressure. Wedge member 73 is connected to the piston of piston cylinder 74. Wedge member 73 is disposed inside housing 72. Wedge member 73 has a tapering surface 73a. Housing 72 has a tapering surface 72a. Tapering surface 72a faces tapering surface 73a. Tapering surface 72a and tapering surface 73a are each inclined in relation to predetermined axis 101. On wedge member 73, spring member 75 exerts elastic force in the direction in which tapering surface 73a comes closer to tapering surface 72a along predetermined axis 101.

[0045] As illustrated in Fig. 5, center 46 abuts on workpiece W placed on rotary table 21 by slide mechanism 70 being supplied with the hydraulic oil for clamping. Accordingly, the clamped state of workpiece W is obtained, in which workpiece W is clamped between center 46 and rotary table 21 (surface plate portion 26).

[0046] At this time, in lock mechanism 71, wedge member 73 is pulled into housing 72 due to the elastic force of spring member 75. As a result of tapering surface 73a being pressed against tapering surface 72a, wedge force occurs. The wedge force acts on slide mechanism 70 (or the quill to which center 46 is attached) so that the position of center 46 in the axial direction of predetermined axis 101 is fixed. Accordingly, even when the supply of the hydraulic pressure to slide mechanism 70 is stopped, center 46 is fixed in the position in which center 46 abuts on workpiece W and the clamped state of workpiece W is maintained.

[0047] As illustrated in Fig. 6, the hydraulic oil for unclamping is supplied to slide mechanism 70 and the hydraulic oil is supplied to piston cylinder 74 in lock mechanism 71, and accordingly, center 46 moves away from workpiece W placed on rotary table 21. Thus, the unclamped state of workpiece W is obtained, in which workpiece W is released between center 46 and rotary table 21 (surface plate portion 26).

[0048] At this time, in lock mechanism 71, the piston of piston cylinder 74 executes strokes in the axial direction of predetermined axis 101 so that wedge member 73 is pushed out of housing 72. By tapering surface 73a moving away from tapering surface 72a, the occurrence of the wedge force is stopped.

[0049] Referring to Figs. 1 to 4, rotary table unit 100 further includes a holding member 31. Holding member 31 holds rotary table 21 and tailstock 41. Holding member 31 holds rotary table 21 and tailstock 41 in an integral manner. Holding member 31 is stationary (still) in the circumferential direction of predetermined axis 101 when rotary table 21 is rotating. Holding member 31 holds rotary table 21 and tailstock 41 without rotating about predetermined axis 101 together with rotary table 21. During the rotation of rotary table 21, the whole of rotary table unit 100 does not rotate about predetermined axis 101.

[0050] Holding member 31 includes a first support portion 36, a second support portion 32, and a connection portion 38. First support portion 36 supports rotary table 21. Second support portion 32 supports tailstock 41. Connection portion 38 connects first support portion 36 and second support portion 32.

[0051] Holding member 31 is made of metal. First support portion 36, second support portion 32, and connection portion 38 are formed in an integral manner by casting for example.

[0052] First support portion 36 is provided in a bottom portion of holding member 31. First support portion 36 has a shape of a floor that is disposed in parallel to an X-Y axes plane and has a thickness direction corresponding to the Z axis direction. First support portion 36 is provided so as to cover bearing housing 24 from the outer side in the radial direction of predetermined axis 101.

[0053] Second support portion 32 is positioned above and away from first support portion 36. Second support portion 32 is provided so as to support exterior body 42 from one side in the X axis direction. Second support portion 32 and exterior body 42 are formed in an integral manner by casting for example.

[0054] Center 46 is disposed between first support portion 36 and second support portion 32 in the axial direction of predetermined axis 101. Surface plate portion 26 is disposed between first support portion 36 and second support portion 32 in the axial direction of predetermined axis 101.

[0055] Connection portion 38 extends like a column in the Z axis direction (the up-and-down direction). A lower end portion of connection portion 38 is contiguous to first support portion 36. An upper end portion of connection portion 38 is contiguous to second support portion 32. In a top view, connection portion 38 is provided so as to surround rotary table 21 (surface plate portion 26) from the one side in the X axis direction. In a top view, connection portion 38 extends while bending along the outer peripheral edge of rotary table 21.

[0056] A plurality of opening portions 33 are provided in connection portion 38. Opening portion 33 is constituted of a through hole extending through connection portion 38 in the radial direction of predetermined axis 101. Opening portion 33 is positioned so as to face rotary table 21 (surface plate portion 26) in the radial direction of predetermined axis 101. The plurality of opening portions 33 are provided at intervals in the circumferential direction of predetermined axis 101. When workpiece W is being machined, a chip or a coolant present on surface plate portion 26 is led through opening portion 33 to a predetermined discharge path provided in a bed (not illustrated).

[0057] In the present embodiment, the turning of workpiece W is performed by causing fixed tool T held at tool spindle 12 to come into contact with workpiece W while workpiece W is being rotated about predetermined axis 101 using rotary table 21. In this case, the amount of deflection of workpiece W centered on predetermined axis 101 can be controlled so as to be small by tailstock 41 (center 46) pressing and supporting workpiece W placed on rotary table 21 in the axial direction of predetermined axis 101. Accordingly, the precision of the machining on workpiece W can be raised.

[0058] In addition, tailstock 41 and rotary table 21 are transferred in an integral manner between the inside and outside of machining area 16. Accordingly, tailstock 41 can be used as a clamper for fixing workpiece W on rotary table 21.

[0059] Referring to Figs. 3 and 4, machine tool 10 further includes a coupler 91. When rotary table unit 100 is placed on base member 51, coupler 91 connects a fluid passage 120 (120p, 120q) between base member 51 and rotary table unit 100. In Figs. 3 and 4, a case where the hydraulic oil for clamping to be supplied to tailstock 41 flows in fluid passage 120 is assumed.

[0060] Base member 51 includes a seat surface 51j. Rotary table unit 100 is seated on seat surface 51j. Fluid passage 120p is provided in base member 51. Rotary table unit 100 (holding member 31) includes a facing surface 31j. Facing surface 31j faces seat surface 51j in the Z axis direction. Fluid passage 120q is provided in rotary table unit 100 (holding member 31).

[0061] Coupler 91 includes a first coupler piece 92 and a second coupler piece 93. First coupler piece 92 is provided in base member 51. First coupler piece 92 is provided in seat surface 51j. Fluid passage 120p communicates with first coupler piece 92. Second coupler piece 93 is provided in rotary table unit 100 (holding member 31). Second coupler piece 93 is provided in facing surface 31j. Second coupler piece 93 is provided so as to face first coupler piece 92 in the Z axis direction. Fluid passage 120q communicates with second coupler piece 93.

[0062] When rotary table unit 100 is placed on base member 51, first coupler piece 92 and second coupler piece 93 are coupled to each other. By fluid passage 120p and fluid passage 120q mutually communicating via coupler 91, fluid passage 120 is connected between base member 51 and rotary table unit 100.

[0063] A plurality of couplers for supplying various kinds of fluids such as the hydraulic oil for unclamping and lubricating oil are provided in base member 51 and rotary table unit 100. Further, in order to enable workpiece W to be clamped and unclamped in set-up station 17, set-up-side placement base 56 is also provided with a coupler for supplying the hydraulic oil to tailstock 41.

[0064] With this structure, various kinds of fluids used in rotary table unit 100 can be supplied to rotary table unit 100 via coupler 91 from the main body side of machine tool 10.

[0065] In contrast, when transfer unit 61 transfers rotary table unit 100, the coupled state of the coupler is canceled, and the supply of the hydraulic pressure to tailstock 41 (slide mechanism 70) is stopped accordingly. Even in such a case, lock mechanism 71 causes center 46 to be fixed in the position in which center 46 abuts on workpiece W, and thus, the state where workpiece W is pressed and supported by tailstock 41 in the axial direction of predetermined axis 101 can be maintained.

[0066] Figs. 7 and 8 are each a cross-sectional view of the machine tool for explaining a rotation stop mechanism for the holding member. Referring to Figs. 7 and 8, machine tool 10 further includes rotation stop mechanism 80.

[0067] When rotary table unit 100 is placed on base member 51, rotation stop mechanism 80 engages between base member 51 and rotary table unit 100 and restricts the rotary movement of holding member 31 relative to base member 51.

[0068] Rotation stop mechanism 80 is made up of a pin member 81 and a pin insertion hole 82. Pin member 81 is provided in base member 51. Pin member 81 projects from seat surface 51j. Pin insertion hole 82 is provided in holding member 31 (first support portion 36). Pin insertion hole 82 is constituted of a bottomed hole, which is opened toward facing surface 31j. Pin insertion hole 82 is provided so as to face pin member 81 in the Z axis direction (the up-and-down direction).

[0069] When rotary table unit 100 is placed on base member 51, rotation stop mechanism 80 is brought into engagement between base member 51 and rotary table unit 100 by pin member 81 being inserted into pin insertion hole 82. Accordingly, when rotary table 21 (surface plate portion 26) is rotating, holding member 31 can be prevented from rotating together with rotary table 21.

[0070] Machine tool 10 may include a plurality of rotation stop mechanisms 80 disposed at respective distances from each other in the plane direction of an X-Y axes plane.

[0071] Fig. 9 is a cross-sectional view illustrating a variation of the rotation stop mechanism in Fig. 7. Referring to Fig. 9, in the present variation, a connection passage 86 is provided in pin member 81. Connection passage 86 is constituted of a through hole extending through pin member 81 in the Z axis direction (the up-and-down direction) and opened toward the space in pin insertion hole 82. Fluid passage 120p communicates with connection passage 86. Fluid passage 120q communicates with the space in pin insertion hole 82.

[0072] With this structure, when rotation stop mechanism 80 engages between base member 51 and rotary table unit 100, the hydraulic oil from fluid passage 120p is led to fluid passage 120q through connection passage 86. As a result, rotation stop mechanism 80 also exerts a function as a coupler for allowing a fluid to pass in addition to the function of stopping the rotation of holding member 31 and thus, the number of components can be reduced.

[0073] To sum up the above-described structure of rotary table unit 100 according to an embodiment of the present invention, rotary table unit 100 in the present embodiment includes rotary table 21 rotatable about predetermined axis 101, tailstock 41 disposed opposite rotary table 21 in the axial direction of predetermined axis 101, and holding member 31 that includes first support portion 36 supporting rotary table 21, second support portion 32 supporting tailstock 41, and connection portion 38 connecting first support portion 36 and second support portion 32, holds rotary table 21 and tailstock 41, and is stationary in the circumferential direction of predetermined axis 101 when rotary table 21 is rotating.

[0074] In another aspect, rotary table unit 100 includes rotary table 21 rotatable about predetermined axis 101, tailstock 41 disposed opposite rotary table 21 in the axial direction of predetermined axis 101, and holding member 31 that includes first support portion 36 supporting rotary table 21, second support portion 32 supporting tailstock 41, and connection portion 38 connecting first support portion 36 and second support portion 32, and holds rotary table 21 and tailstock 41.

[0075] It should be understood that the herein-disclosed embodiments are presented by way of illustration and example in every respect and are not to be taken by way of limitation. The scope of the present invention is not defined by the description above but is defined by the claims, and is intended to include all changes within the purport and scope equivalent to the claims.

[0076] This application is based on Japanese Patent Application No. 2023-116432 filed on July 18, 2023 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

[0077] 10 machine tool; 12 tool spindle; 16 machining area; 17 set-up station; 18 cover body; 21 rotary table; 22 shaft; 24 bearing housing; 25 clutch shaft; 26 surface plate portion; 29 bearing; 31 holding member; 31j facing surface; 32 second support portion; 33 opening portion; 36 first support portion; 38 connection portion; 41 tailstock; 42 exterior body; 46 center; 51 base member; 51j seat surface; 52 motor; 53 output shaft; 56 set-up-side placement base; 61 transfer unit; 62A first arm member; 62B second arm member; 63 joint portion; 66 turn cover; 70 slide mechanism; 71 lock mechanism; 72 housing; 72a, 73a tapering surface; 73 wedge member; 74 piston cylinder; 75 spring member; 80 rotation stop mechanism; 81 pin member; 82 pin insertion hole; 86 connection passage; 91 coupler; 92 first coupler piece; 93 second coupler piece; 100 rotary table unit; 100A first rotary table unit; 100B second rotary table unit; 101 predetermined axis; 102 turn central axis; 103 rotation central axis; 110 boundary surface; 120, 120p, 120q fluid passage.

Claims

1. A rotary table unit comprising: a rotary table that a workpiece is placed on and is rotatable about a predetermined axis; a tailstock disposed opposite the rotary table in an axial direction of the predetermined axis; and a holding member that includes a first support portion supporting the rotary table, a second support portion supporting the tailstock, and a connection portion connecting the first support portion and the second support portion, holds the rotary table and the tailstock, and is stationary in a circumferential direction of the predetermined axis when the rotary table is rotating.

2. The rotary table unit according to claim 1, wherein the tailstock includes a center extending on the predetermined axis, a slide mechanism that slides the center in the axial direction of the predetermined axis by being supplied with hydraulic pressure, and a lock mechanism that causes the center to be fixed in a position in which the center abuts on the workpiece placed on the rotary table when no hydraulic pressure is being supplied to the slide mechanism.

3. A machine tool comprising: the rotary table unit according to claim 1; and a transfer unit that transfers the rotary table unit between inside and outside of a machining area.

4. The machine tool according to claim 3, further comprising: a base member provided in the machining area; a coupler that connects a fluid passage between the base member and the rotary table unit when the rotary table unit is placed on the base member; and a rotation stop mechanism that, when the rotary table unit is placed on the base member, engages between the base member and the rotary table unit and restricts rotary movement of the holding member relative to the base member.

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